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'4' == Outdated reference: A later version (-05) exists of draft-ietf-policy-qos-info-model-04 == Outdated reference: A later version (-06) exists of draft-ietf-ipsp-config-policy-model-03 -- Possible downref: Normative reference to a draft: ref. '7' ** Obsolete normative reference: RFC 2234 (ref. '8') (Obsoleted by RFC 4234) ** Obsolete normative reference: RFC 2373 (ref. '10') (Obsoleted by RFC 3513) ** Obsolete normative reference: RFC 2252 (ref. '11') (Obsoleted by RFC 4510, RFC 4512, RFC 4517, RFC 4523) -- Possible downref: Non-RFC (?) normative reference: ref. '12' -- Possible downref: Non-RFC (?) normative reference: ref. '13' -- Possible downref: Non-RFC (?) normative reference: ref. '14' Summary: 8 errors (**), 0 flaws (~~), 11 warnings (==), 12 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Policy Framework Working Group B. Moore 2 INTERNET-DRAFT L. Rafalow 3 Updates: 3060 IBM 4 Category: Standards Track Y. Ramberg 5 Y. Snir 6 A. Westerinen 7 Cisco Systems 8 R. Chadha 9 Telcordia Technologies 10 M. Brunner 11 NEC 12 R. Cohen 13 Ntear LLC 14 J. Strassner 15 INTELLLIDEN, Inc. 16 September 2001 18 Policy Core Information Model Extensions 20 21 Tuesday, September 04, 2001, 2:35 PM 23 Status of this Memo 25 This document is an Internet-Draft and is in full conformance with all 26 provisions of Section 10 of RFC2026. 28 Internet-Drafts are working documents of the Internet Engineering Task 29 Force (IETF), its areas, and its working groups. Note that other groups 30 may also distribute working documents as Internet-Drafts. 32 Internet-Drafts are draft documents valid for a maximum of six months and 33 may be updated, replaced, or obsoleted by other documents at any time. 34 It is inappropriate to use Internet-Drafts as reference material or to 35 cite them other than as "work in progress." 37 The list of current Internet-Drafts can be accessed at 38 http://www.ietf.org/ietf/1id-abstracts.txt 40 The list of Internet-Draft Shadow Directories can be accessed at 41 http://www.ietf.org/shadow.html 43 Copyright Notice 45 Copyright (C) The Internet Society (2001). All Rights Reserved. 47 Abstract 49 This document proposes a number of changes to the Policy Core Information 50 Model (PCIM, RFC 3060). These changes include both extensions of PCIM 51 into areas that it did not previously cover, and changes to the existing 52 PCIM classes and associations. Both sets of changes are done in a way 53 that, to the extent possible, preserves interoperability with 54 implementations of the original PCIM model. 56 Table of Contents 58 1. Introduction......................................................5 59 2. Overview of the Changes...........................................5 60 2.1. How to Change an Information Model...........................5 61 2.2. List of Changes to the Model.................................6 62 2.2.1. Changes to PolicyRepository................................6 63 2.2.2. Additional Associations and Additional Reusable Elements...6 64 2.2.3. Priorities and Decision Strategies.........................6 65 2.2.4. Policy Roles...............................................7 66 2.2.5. CompoundPolicyConditions and CompoundPolicyActions.........7 67 2.2.6. Variables and Values.......................................7 68 2.2.7. Domain-Level Packet Filtering..............................8 69 2.2.8. Device-Level Packet Filtering..............................8 70 3. The Updated Class and Association Class Hierarchies...............8 71 4. Areas of Extension to PCIM.......................................12 72 4.1. Policy Scope................................................13 73 4.1.1. Levels of Abstraction: Domain- and Device-Level Policies..13 74 4.1.2. Administrative and Functional Scopes......................13 75 4.2. Reusable Policy Elements....................................14 76 4.3. Policy Sets.................................................15 77 4.4. Nested Policy Rules.........................................15 78 4.4.1. Usage Rules for Nested Rules..............................15 79 4.4.2. Motivation................................................16 80 4.5. Priorities and Decision Strategies..........................17 81 4.5.1. Structuring Decision Strategies...........................18 82 4.5.2. Side Effects..............................................19 83 4.5.3. Multiple PolicySet Trees For a Resource...................20 84 4.5.4. Deterministic Decisions...................................21 85 4.6. Policy Roles................................................21 86 4.6.1. Comparison of Roles in PCIM with Roles in snmpconf........22 87 4.6.2. Addition of PolicyRoleCollection to PCIMe.................22 88 4.6.3. Roles for PolicyGroups....................................23 89 4.7. Compound Policy Conditions and Compound Policy Actions......25 90 4.7.1. Compound Policy Conditions................................25 91 4.7.2. Compound Policy Actions...................................25 92 4.8. Variables and Values........................................26 93 4.8.1. Simple Policy Conditions..................................26 94 4.8.2. Using Simple Policy Conditions............................27 95 4.8.3. The Simple Condition Operator.............................28 96 4.8.4. SimplePolicyActions.......................................31 97 4.8.5. Policy Variables..........................................32 98 4.8.6. Explicitly Bound Policy Variables.........................33 99 4.8.7. Implicitly Bound Policy Variables.........................34 100 4.8.8. Structure and Usage of Pre-Defined Variables..............34 101 4.8.9. Rationale for Modeling Implicit Variables as Classes......35 102 4.8.10. Policy Values............................................36 103 4.9. Packet Filtering............................................37 104 4.9.1. Domain-Level Packet Filters...............................37 105 4.9.2. Device-Level Packet Filters...............................39 106 4.10. Conformance to PCIM and PCIMe..............................39 107 5. Class Definitions................................................40 108 5.1. The Abstract Class "PolicySet"..............................40 109 5.2. Update PCIM's Class "PolicyGroup"...........................41 110 5.3. Update PCIM's Class "PolicyRule"............................41 111 5.4. The Class "SimplePolicyCondition"...........................42 112 5.5. The Class "CompoundPolicyCondition".........................42 113 5.6. The Class "CompoundFilterCondition".........................43 114 5.7. The Class "SimplePolicyAction"..............................43 115 5.8. The Class "CompoundPolicyAction"............................44 116 5.9. The Abstract Class "PolicyVariable".........................45 117 5.10. The Class "PolicyExplicitVariable".........................46 118 5.10.1. The Single-Valued Property "ModelClass"..................46 119 5.10.2. The Single-Valued Property ModelProperty.................46 120 5.11. The Abstract Class "PolicyImplicitVariable"................47 121 5.11.1. The Multi-Valued Property "ValueTypes"...................47 122 5.12. Subclasses of "PolicyImplicitVariable" Specified in PCIMe..47 123 5.12.1. The Class "PolicySourceIPv4Variable".....................47 124 5.12.2. The Class "PolicySourceIPv6Variable".....................48 125 5.12.3. The Class "PolicyDestinationIPv4Variable"................48 126 5.12.4. The Class "PolicyDestinationIPv6Variable"................48 127 5.12.5. The Class "PolicySourcePortVariable".....................49 128 5.12.6. The Class "PolicyDestinationPortVariable"................49 129 5.12.7. The Class "PolicyIPProtocolVariable".....................49 130 5.12.8. The Class "PolicyIPVersionVariable"......................50 131 5.12.9. The Class "PolicyIPToSVariable"..........................50 132 5.12.10. The Class "PolicyDSCPVariable"..........................50 133 5.12.11. The Class "PolicyFlowIdVariable"........................50 134 5.12.12. The Class "PolicySourceMACVariable".....................51 135 5.12.13. The Class "PolicyDestinationMACVariable"................51 136 5.12.14. The Class "PolicyVLANVariable"..........................51 137 5.12.15. The Class "PolicyCoSVariable"...........................51 138 5.12.16. The Class "PolicyEthertypeVariable".....................52 139 5.12.17. The Class "PolicySourceSAPVariable".....................52 140 5.12.18. The Class "PolicyDestinationSAPVariable"................52 141 5.12.19. The Class "PolicySNAPVariable"..........................52 142 5.12.20. The Class "PolicyFlowDirectionVariable".................53 143 5.13. The Abstract Class "PolicyValue"...........................53 144 5.14. Subclasses of "PolicyValue" Specified in PCIMe.............53 145 5.14.1. The Class "PolicyIPv4AddrValue"..........................53 146 5.14.2. The Class "PolicyIPv6AddrValue...........................55 147 5.14.3. The Class "PolicyMACAddrValue"...........................56 148 5.14.4. The Class "PolicyStringValue"............................56 149 5.14.5. The Class "PolicyBitStringValue".........................57 150 5.14.6. The Class "PolicyIntegerValue"...........................57 151 5.14.7. The Class "PolicyBooleanValue"...........................58 152 5.15. The Class "PolicyRoleCollection"...........................59 153 5.15.1. The Single-Valued Property "PolicyRole"..................59 154 5.16. The Class "ReusablePolicyContainer"........................59 155 5.17. Deprecate PCIM's Class "PolicyRepository"..................59 156 5.18. The Abstract Class "FilterEntryBase".......................60 157 5.19. The Class "IpHeadersFilter"................................60 158 5.19.1. The Property HdrIpVersion................................61 159 5.19.2. The Property HdrSrcAddress...............................61 160 5.19.3. The Property HdrSrcMask..................................61 161 5.19.4. The Property HdrDestAddress..............................61 162 5.19.5. The Property HdrDestMask.................................62 163 5.19.6. The Property HdrProtocolID...............................62 164 5.19.7. The Property HdrSrcPortStart.............................62 165 5.19.8. The Property HdrSrcPortEnd...............................62 166 5.19.9. The Property HdrDestPortStart............................63 167 5.19.10. The Property HdrDestPortEnd.............................63 168 5.19.11. The Property HdrDSCP....................................63 169 5.19.12. The Property HdrFlowLabel...............................64 170 5.20. The Class "8021Filter".....................................64 171 5.20.1. The Property 8021HdrSrcMACAddr...........................64 172 5.20.2. The Property 8021HdrSrcMACMask...........................64 173 5.20.3. The Property 8021HdrDestMACAddr..........................65 174 5.20.4. The Property 8021HdrDestMACMask..........................65 175 5.20.5. The Property 8021HdrProtocolID...........................65 176 5.20.6. The Property 8021HdrPriorityValue........................65 177 5.20.7. The Property 8021HdrVLANID...............................65 178 5.21. The Class FilterList.......................................66 179 5.21.1. The Property Direction...................................66 180 6. Association and Aggregation Definitions..........................67 181 6.1. The Aggregation "PolicySetComponent"........................67 182 6.2. Deprecate PCIM's Aggregation "PolicyGroupInPolicyGroup".....67 183 6.3. Deprecate PCIM's Aggregation "PolicyRuleInPolicyGroup"......68 184 6.4. The Abstract Association "PolicySetInSystem"................68 185 6.5. Update PCIM's Weak Association "PolicyGroupInSystem"........69 186 6.6. Update PCIM's Weak Association "PolicyRuleInSystem".........69 187 6.7. The Abstract Aggregation "PolicyConditionStructure".........70 188 6.8. Update PCIM's Aggregation "PolicyConditionInPolicyRule".....70 189 6.9. The Aggregation "PolicyConditionInPolicyCondition"..........70 190 6.10. The Abstract Aggregation "PolicyActionStructure"...........71 191 6.11. Update PCIM's Aggregation "PolicyActionInPolicyRule".......71 192 6.12. The Aggregation "PolicyActionInPolicyAction"...............71 193 6.13. The Aggregation "PolicyVariableInSimplePolicyCondition"....71 194 6.14. The Aggregation "PolicyValueInSimplePolicyCondition".......72 195 6.15. The Aggregation "PolicyVariableInSimplePolicyAction".......73 196 6.16. The Aggregation "PolicyValueInSimplePolicyAction"..........73 197 6.17. The Association "ReusablePolicy"...........................74 198 6.18. Deprecate PCIM's "PolicyConditionInPolicyRepository".......74 199 6.19. Deprecate PCIM's "PolicyActionInPolicyRepository"..........75 200 6.20. The Association ExpectedPolicyValuesForVariable............75 201 6.21. The Aggregation "ContainedDomain"..........................76 202 6.22. Deprecate PCIM's "PolicyRepositoryInPolicyRepository"......76 203 6.23. The Aggregation "EntriesInFilterList"......................76 204 6.23.1. The Reference GroupComponent.............................77 205 6.23.2. The Reference PartComponent..............................77 206 6.23.3. The Property EntrySequence...............................77 207 6.24. The Aggregation "ElementInPolicyRoleCollection"............77 208 6.25. The Weak Association "PolicyRoleCollectionInSystem"........78 209 7. Intellectual Property............................................78 210 8. Acknowledgements.................................................79 211 9. Security Considerations..........................................79 212 10. References......................................................79 213 11. Authors' Addresses..............................................80 214 12. Full Copyright Statement........................................82 215 13. Appendix A: Closed Issues.......................................82 217 1. Introduction 219 This document (PCIM Extensions, abbreviated here to PCIMe) proposes a 220 number of changes to the Policy Core Information Model (PCIM, RFC 3060 221 [3]). These changes include both extensions of PCIM into areas that it 222 did not previously cover, and changes to the existing PCIM classes and 223 associations. Both sets of changes are done in a way that, to the extent 224 possible, preserves interoperability with implementations of the original 225 PCIM model. 227 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 228 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 229 document are to be interpreted as described in RFC 2119, reference [1]. 231 2. Overview of the Changes 233 2.1. How to Change an Information Model 235 The Policy Core Information Model is closely aligned with the DMTF's CIM 236 Core Policy model. Since there is no separately documented set of rules 237 for specifying IETF information models such as PCIM, it is reasonable to 238 look to the CIM specifications for guidance on how to modify and extend 239 the model. Among the CIM rules for changing an information model are the 240 following. Note that everything said here about "classes" applies to 241 association classes (including aggregations) as well as to non- 242 association classes. 244 o Properties may be added to existing classes. 245 o Classes, and individual properties, may be marked as DEPRECATED. 246 If there is a replacement feature for the deprecated class or 247 property, it is identified explicitly. Otherwise the notation "No 248 value" is used. In this document, the notation "DEPRECATED FOR 249 " is used to indicate that a feature has been 250 deprecated, and to identify its replacement feature. 251 o Classes may be inserted into the inheritance hierarchy above 252 existing classes, and properties from the existing classes may 253 then be "pulled up" into the new classes. The net effect is that 254 the existing classes have exactly the same properties they had 255 before, but the properties are inherited rather than defined 256 explicitly in the classes. 257 o New subclasses may be defined below existing classes. 259 2.2. List of Changes to the Model 261 The following subsections provide a very brief overview of the changes to 262 PCIM defined in PCIMe. In several cases, the origin of the change is 263 noted, as QPIM [5], ICPM [6], or QDDIM [14]. 265 2.2.1. Changes to PolicyRepository 267 Because of the potential for confusion with the Policy Framework 268 component Policy Repository (from the four-box picture: Policy Management 269 Tool, Policy Repository, PDP, PEP), "PolicyRepository" is a bad name for 270 the PCIM class representing a container of reusable policy elements. 271 Thus the class PolicyRepository is being replaced with the class 272 ReusablePolicyContainer. To accomplish this change, it is necessary to 273 deprecate the PCIM class PolicyRepository and its three associations, and 274 replace them with a new class ReusablePolicyContainer and new 275 associations. 277 As a separate change, the associations for ReusablePolicyContainer are 278 being broadened, to allow a ReusablePolicyContainer to contain any 279 reusable policy elements. In PCIM, the only associations defined for a 280 PolicyRepository were for it to contain reusable policy conditions and 281 policy actions. 283 2.2.2. Additional Associations and Additional Reusable Elements 285 The PolicyRuleInPolicyRule and PolicyGroupInPolicyRule aggregations have, 286 in effect, been imported from QPIM. ("In effect" because these two 287 aggregations, as well as PCIM'e two aggregations PolicyGroupInPolicyGroup 288 and PolicyRuleInPolicyGroup, are all being combined into a single 289 aggregation PolicySetComponent.) These aggregations make it possible to 290 define larger "chunks" of reusable policy to place in a 291 ReusablePolicyContainer. These aggregations also introduce new semantics 292 representing the contextual implications of having one PolicyRule 293 executing within the scope of another PolicyRule. 295 2.2.3. Priorities and Decision Strategies 297 Drawing from both QPIM and ICPM, the Priority property has been 298 deprecated in PolicyRule, and placed instead on the aggregation 299 PolicySetComponent. The QPIM rules for resolving relative priorities 300 across nested PolicyGroups and PolicyRules have been incorporated into 301 PCIMe as well. With the removal of the Priority property from 302 PolicyRule, a new modeling dependency is introduced. In order to 303 prioritize a PolicyRule/PolicyGroup relative to other 304 PolicyRules/PolicyGroups, the elements being prioritized must all reside 305 in one of three places: in a common PolicyGroup, in a common PolicyRule, 306 or in a common System. 308 In the absence of any clear, general criterion for detecting policy 309 conflicts, the PCIM restriction stating that priorities are relevant only 310 in the case of conflicts is being removed. In its place, a 311 PolicyDecisionStrategy property has been added to the PolicyGroup and 312 PolicyRule classes. This property allows policy administrator to select 313 one of two behaviors with respect to rule evaluation: either perform the 314 actions for all PolicyRules whose conditions evaluate to TRUE, or perform 315 the actions only for the highest-priority PolicyRule whose conditions 316 evaluate to TRUE. (This is accomplished by placing the 317 PolicyDecisionStrategy property in an abstract class PolicySet, from 318 which PolicyGroup and PolicyRule are derived.) The QPIM rules for 319 applying decision strategies to a nested set of PolicyGroups and 320 PolicyRules have also been imported. 322 2.2.4. Policy Roles 324 The concept of policy roles is added to PolicyGroups (being present 325 already in the PolicyRule class). This is accomplished via a new 326 superclass for both PolicyRules and PolicyGroups - PolicySet. For nested 327 PolicyRules and PolicyGroups, any roles associated with the outer rule or 328 group are automatically "inherited" by the nested one. Additional roles 329 may be added at the level of a nested rule or group. 331 It was also observed that there is no mechanism in PCIM for assigning 332 roles to resources. For example, while it is possible in PCIM to 333 associate a PolicyRule with the role "FrameRelay&&WAN", there is no way 334 to indicate which interfaces match this criterion. A new 335 PolicyRoleCollection class has been defined in PCIMe, representing the 336 collection of resources associated with a particular role. The linkage 337 between a PolicyRule or PolicyGroup and a set of resources is then 338 represented by an instance of PolicyRoleCollection. Equivalent values 339 should be defined in the PolicyRoles property of PolicyRules and 340 PolicyGroups, and in the PolicyRole property in PolicyRoleCollection. 342 2.2.5. CompoundPolicyConditions and CompoundPolicyActions 344 The concept of a CompoundPolicyCondition has also been imported into 345 PCIMe from QPIM, and broadened to include a parallel 346 CompoundPolicyAction. In both cases the idea is to create reusable 347 "chunks" of policy that can exist as named elements in a 348 ReusablePolicyContainer. The "Compound" classes and their associations 349 incorporate the condition and action semantics that PCIM defined at the 350 PolicyRule level: DNF/CNF for conditions, and ordering for actions. 352 Compound conditions and actions are defined to work with any component 353 conditions and actions. In other words, while the components may be 354 instances, respectively, of SimplePolicyCondition and SimplePolicyAction 355 (discussed immediately below), they need not be. 357 2.2.6. Variables and Values 359 The SimplePolicyCondition / PolicyVariable / PolicyValue structure has 360 been imported into PCIMe from QPIM. A list of PCIMe-level variables is 361 defined, as well as a list of PCIMe-level values. Other variables and 362 values may, if necessary, be defined in submodels of PCIMe. For example, 363 QPIM defines a set of implicit variables corresponding to fields in RSVP 364 flows. 366 A corresponding SimplePolicyAction / PolicyVariable / PolicyValue 367 structure is also defined. While the semantics of a 368 SimplePolicyCondition are "variable matches value", a SimplePolicyAction 369 has the semantics "set variable to value". 371 2.2.7. Domain-Level Packet Filtering 373 For packet filtering specified at the domain level, a set of 374 PolicyVariables and PolicyValues are defined, corresponding to the fields 375 in an IP packet header plus the most common Layer 2 frame header fields. 376 It is expected that domain-level policy conditions that filter on these 377 header fields will be expressed in terms of CompoundPolicyConditions 378 built up from SimplePolicyConditions that use these variables and values. 379 An additional PolicyVariable, PacketDirection, is also defined, to 380 indicate whether a packet being filtered is traveling inbound or outbound 381 on an interface. 383 2.2.8. Device-Level Packet Filtering 385 For packet filtering expressed at the device level, including the packet 386 classifier filters modeled in QDDIM, the variables and values discussed 387 in Section 2.2.7 need not be used. Filter classes derived from the CIM 388 FilterEntryBase class hierarchy are available for use in these contexts. 389 These latter classes have two important differences from the domain-level 390 classes: 392 o They support specification of filters for all of the fields in a 393 particular protocol header in a single object instance. With the 394 domain-level classes, separate instances are needed for each 395 header field. 396 o They provide native representations for the filter values, as 397 opposed to the string representation used by the domain-level 398 classes. 400 Device-level filter classes for the IP-related headers (IP, UDP, and TCP) 401 and the 802 MAC headers are defined, respectively, in sections 5.19 and 402 5.20. 404 3. The Updated Class and Association Class Hierarchies 406 The following figure shows the class inheritance hierarchy for PCIMe. 407 Changes from the PCIM hierarchy are noted parenthetically. 409 ManagedElement (abstract) 410 | 411 +--Policy (abstract) 412 | | 413 | +---PolicySet (abstract -- new - 4.3) 414 | | | 415 | | +---PolicyGroup (moved - 4.3) 416 | | | 417 | | +---PolicyRule (moved - 4.3) 418 | | 419 | +---PolicyCondition (abstract) 420 | | | 421 | | +---PolicyTimePeriodCondition 422 | | | 423 | | +---VendorPolicyCondition 424 | | | 425 | | +---SimplePolicyCondition (new - 4.8.1) 426 | | | 427 | | +---CompoundPolicyCondition (new - 4.7.1) 428 | | | 429 | | +---CompoundFilterCondition (new - 4.9) 430 | | 431 | +---PolicyAction (abstract) 432 | | | 433 | | +---VendorPolicyAction 434 | | | 435 | | +---SimplePolicyAction (new - 4.8.4) 436 | | | 437 | | +---CompoundPolicyAction (new - 4.7.2) 438 | | 439 | +---PolicyVariable (abstract -- new - 4.8.5) 440 | | | 441 | | +---PolicyExplicitVariable (new - 4.8.6) 442 | | | 443 | | +---PolicyImplicitVariable (abstract -- new - 4.8.7) 444 | | | 445 | | +---(subtree of more specific classes -- new - 5.12) 446 | | 447 | +---PolicyValue (abstract -- new - 4.8.10) 448 | | 449 | +---(subtree of more specific classes -- new - 5.14) 450 | 451 +--Collection (abstract -- newly referenced) 452 | | 453 | +--PolicyRoleCollection (new - 4.6.2) 454 (continued on following page) 455 (continued from previous page) 456 ManagedElement(abstract) 457 | 458 +--ManagedSystemElement (abstract) 459 | 460 +--LogicalElement (abstract) 461 | 462 +--System (abstract) 463 | | 464 | +--AdminDomain (abstract) 465 | | 466 | +---ReusablePolicyContainer (new - 4.2) 467 | | 468 | +---PolicyRepository (deprecated - 4.2) 469 | 470 +--FilterEntryBase (abstract -- new - 5.18) 471 | | 472 | +--IpHeadersFilter (new - 5.19) 473 | | 474 | +--8021Filter (new - 5.20) 475 | 476 +--FilterList (new - 5.21) 478 Figure 1. Class Inheritance Hierarchy for PCIMe 479 The following figure shows the association class hierarchy for PCIMe. As 480 before, changes from PCIM are noted parenthetically. 482 [unrooted] 483 | 484 +---PolicyComponent (abstract) 485 | | 486 | +---PolicySetComponent (new - 4.3) 487 | | 488 | +---PolicyGroupInPolicyGroup (deprecated - 4.3) 489 | | 490 | +---PolicyRuleInPolicyGroup (deprecated - 4.3) 491 | | 492 | +---PolicyConditionStructure (abstract -- new - 4.7.1) 493 | | | 494 | | +---PolicyConditionInPolicyRule (moved - 4.7.1) 495 | | | 496 | | +---PolicyConditionInPolicyCondition (new - 4.7.1) 497 | | 498 | +---PolicyRuleValidityPeriod 499 | | 500 | +---PolicyActionStructure (abstract -- new - 4.7.2) 501 | | | 502 | | +---PolicyActionInPolicyRule (moved - 4.7.2) 503 | | | 504 | | +---PolicyActionInPolicyAction (new - 4.7.2) 505 | | 506 | +---PolicyVariableInSimplePolicyCondition (new - 4.8.2) 507 | | 508 | +---PolicyValueInSimplePolicyCondition (new - 4.8.2) 509 | | 510 | +---PolicyVariableInSimplePolicyAction (new - 4.8.4) 511 | | 512 | +---PolicyValueInSimplePolicyAction (new - 4.8.4) 514 (continued on following page) 515 (continued from previous page) 516 [unrooted] 517 | 518 +---Dependency (abstract) 519 | | 520 | +---PolicyInSystem (abstract) 521 | | | 522 | | +---PolicySetInSystem (abstract, new - 4.3) 523 | | | | 524 | | | +---PolicyGroupInSystem 525 | | | | 526 | | | +---PolicyRuleInSystem 527 | | | 528 | | +---ReusablePolicy (new - 4.2) 529 | | | 530 | | +---PolicyConditionInPolicyRepository (deprecated - 4.2) 531 | | | 532 | | +---PolicyActionInPolicyRepository (deprecated - 4.2) 533 | | 534 | +---ExpectedPolicyValuesForVariable (new - 4.8) 535 | | 536 | +---PolicyRoleCollectionInSystem (new - 4.6.2) 537 | 538 +---Component (abstract) 539 | | 540 | +---SystemComponent 541 | | | 542 | | +---ContainedDomain (new - 4.2) 543 | | | 544 | | +---PolicyRepositoryInPolicyRepository (deprecated - 4.2) 545 | | 546 | +---EntriesInFilterList (new - 6.23) 547 | 548 +---MemberOfCollection (newly referenced) 549 | 550 +--- ElementInPolicyRoleCollection (new - 4.6.2) 552 Figure 2. Association Class Inheritance Hierarchy for PCIMe 554 In addition to these changes that show up at the class and association 555 class level, there are other changes from PCIM involving individual class 556 properties. In some cases new properties are introduced into existing 557 classes, and in other cases existing properties are deprecated (without 558 deprecating the classes that contain them). 560 4. Areas of Extension to PCIM 562 The following subsections describe each of the areas for which PCIM 563 extensions are being defined. 565 4.1. Policy Scope 567 Policy scopes may be thought of in two dimensions: 1) the level of 568 abstraction of the policy specification and 2) the applicability of 569 policies to a set of managed resources. 571 4.1.1. Levels of Abstraction: Domain- and Device-Level Policies 573 Policies vary in level of abstraction, from the business-level expression 574 of service level agreements (SLAs) to the specification of a set of rules 575 that apply to devices in a network. Those latter policies can, 576 themselves, be classified into at least two groups: those policies 577 consumed by a Policy Decision Point (PDP) that specify the rules for an 578 administrative and functional domain, and those policies consumed by a 579 Policy Enforcement Point (PEP) that specify the device-specific rules for 580 a functional domain. The higher-level rules consumed by a PDP, called 581 domain-level policies, may have late binding variables unspecified, or 582 specified by a classification, whereas the device-level rules are likely 583 to have fewer unresolved bindings. 585 There is a relationship between these levels of policy specification that 586 is out of scope for this standards effort, but that is necessary in the 587 development and deployment of a usable policy-based configuration system. 588 An SLA-level policy transformation to the domain-level policy may be 589 thought of as analogous to a visual builder that takes human input and 590 develops a programmatic rule specification. The relationship between the 591 domain-level policy and the device-level policy may be thought of as 592 analogous to that of a compiler and linkage editor that translates the 593 rules into specific instructions that can be executed on a specific type 594 of platform. 596 PCIM and PCIMe may be used to specify rules at any and all of these 597 levels of abstraction. However, at different levels of abstraction, 598 different mechanisms may be more or less appropriate. 600 4.1.2. Administrative and Functional Scopes 602 Administrative scopes for policy are represented in PCIM and in these 603 extensions to PCIM as System subclass instances. Typically, a domain- 604 level policy would be scoped by an AdminDomain instance (or by a 605 hierarchy of AdminDomain instances) whereas a device-level policy might 606 be scoped by a System instance that represents the PEP (e.g., an instance 607 of ComputerSystem, see CIM [4]). In addition to collecting policies into 608 an administrative domain, these System classes may also aggregate the 609 resources to which the policies apply. 611 Functional scopes (sometimes referred to as functional domains) are 612 generally defined by the submodels derived from PCIM and PCIMe, and 613 correspond to the service or services to which the policies apply. So, 614 for example, Quality of Service may be thought of as a functional scope, 615 or Diffserv and Intserv may each be thought of as functional scopes. 616 These scoping decisions are represented by the structure of the submodels 617 derived from PCIM and PCIMe, and may be reflected in the number and types 618 of PEP policy client(s), services, and the interaction between policies. 619 Policies in different functional scopes are organized into disjoint sets 620 of policy rules. Different functional domains may share some roles, some 621 conditions, and even some actions. The rules from different functional 622 domains may even be enforced at the same managed resource, but for the 623 purposes of policy evaluation they are separate. See section 4.5.3 for 624 more information. 626 The functional scopes MAY be reflected in administrative scopes. That 627 is, deployments of policy may have different administrative scopes for 628 different functional scopes, but there is no requirement to do so. 630 4.2. Reusable Policy Elements 632 In PCIM, a distinction was drawn between reusable PolicyConditions and 633 PolicyActions and rule-specific ones. The PolicyRepository class was 634 also defined, to serve as a container for these reusable elements. The 635 name "PolicyRepository" has proven to be an unfortunate choice for the 636 class that serves as a container for reusable policy elements. This term 637 is already used in documents like the Policy Framework, to denote the 638 location from which the PDP retrieves all policy specifications, and into 639 which the Policy Management Tool places all policy specifications. 640 Consequently, the PolicyRepository class is being deprecated, in favor of 641 a new class ReusablePolicyContainer. 643 When a class is deprecated, any associations that refer to it must also 644 be deprecated. So replacements are needed for the two associations 645 PolicyConditionInPolicyRepository and PolicyActionInPolicyRepository, as 646 well as for the aggregation PolicyRepositoryInPolicyRepository. In 647 addition to renaming the PolicyRepository class to 648 ReusablePolicyContainer, however, PCIMe is also broadening the types of 649 policy elements that can be reusable. Consequently, rather than 650 providing one-for-one replacements for the two associations, a single 651 higher-level association ReusablePolicy is defined. This new association 652 allows any policy element (that is, an instance of any subclass of the 653 abstract class Policy) to be placed in a ReusablePolicyContainer. 655 Summarizing, the following changes in Sections 5 and 6 are the result of 656 this item: 658 o The class ReusablePolicyContainer is defined. 659 o PCIM's PolicyRepository class is deprecated. 660 o The association ReusablePolicy is defined. 661 o PCIM's PolicyConditionInPolicyRepository association is deprecated. 662 o PCIM's PolicyActionInPolicyRepository association is deprecated. 663 o The aggregation ContainedDomain is defined. 664 o PCIM's PolicyRepositoryInPolicyRepository aggregation is deprecated. 666 4.3. Policy Sets 668 A "policy" can be thought of as a coherent set of rules to administer, 669 manage, and control access to network resources ("Policy Terminology", 670 reference [12]). The structuring of these coherent sets of rules into 671 subsets is enhanced in this document. In Section 4.4, we discuss the new 672 options for the nesting of policy rules. 674 A new abstract class, PolicySet, is introduced to provide an abstraction 675 for a set of rules. It is derived from Policy, and it is inserted into 676 the inheritance hierarchy above both PolicyGroup and PolicyRule. This 677 reflects the additional structural flexibility and semantic capability of 678 both subclasses. 680 Two properties are defined in PolicySet: PolicyDecisionStrategy and 681 PolicyRoles. The PolicyDecisionStrategy property is included in 682 PolicySet to define the evaluation relationship among the rules in the 683 policy set. See Section 4.5 for more information. The PolicyRoles 684 property is included in PolicySet to characterize the resources to which 685 the PolicySet applies. See Section 4.6 for more information. 687 Along with the definition of the PolicySet class, a new concrete 688 aggregation class is defined that will also be discussed in the following 689 sections. PolicySetComponent is defined as a subclass of 690 PolicyComponent; it provides the containment relationship for a PolicySet 691 in a PolicySet. PolicySetComponent replaces the two PCIM aggregations 692 PolicyGroupInPolicyGroup and PolicyRuleInPolicyGroup, so these two 693 aggregations are deprecated. 695 A PolicySet's relationship to an AdminDomain or other administrative 696 scoping system (for example, a ComputerSystem) is represented by the 697 PolicySetInSystem abstract association. This new association is derived 698 from PolicyInSystem, and the PolicyGroupInSystem and PolicyRuleInSystem 699 associations are now derived from PolicySetInSystem instead of directly 700 from PolicyInSystem. The PolicySetInSystem.Priority property is 701 discussed in Section 4.5.3. 703 4.4. Nested Policy Rules 705 As previously discussed, policy is described by a set of policy rules 706 that may be grouped into subsets. In this section we introduce the 707 notion of nested rules, or the ability to define rules within rules. 708 Nested rules are also called sub-rules, and we use both terms in this 709 document interchangeably. The aggregation PolicySetComponent is used to 710 represent the nesting of a policy rule in another policy rule. 712 4.4.1. Usage Rules for Nested Rules 714 The relationship between rules and sub-rules is defined as follows: 716 o The parent rule's condition clause is a condition for evaluation 717 of all nested rules; that is, the conditions of the parent are 718 logically ANDed to the conditions of the sub-rules. If the parent 719 rule's condition clause evaluates to FALSE, sub-rules MAY be 720 skipped since they also evaluate to FALSE. 721 o If the parent rule's condition evaluates to TRUE, the set of sub- 722 rules SHALL BE evaluated according to the decision strategy and 723 priorities as discussed in Section 4.5. 724 o If the parent rule's condition evaluates to TRUE, the parent 725 rule's set of actions is executed BEFORE execution of the sub- 726 rules� actions. The parent rule's actions are not to be confused 727 with default actions. A default action is one that is to be 728 executed only if none of the more specific sub-rules are executed. 729 If a default action needs to be specified, it needs to be defined 730 as an action that is part of a catchall sub-rule associated with 731 the parent rule. The association linking the default action(s) in 732 this special sub-rule should have the lowest priority relative to 733 all other sub-rule associations: 735 if parent-condition then parent rule's action 736 if condA then actA 737 if condB then ActB 738 if True then default action 740 Such a default action functions as a default when FirstMatching 741 decision strategies are in effect (see section 4.5). If 742 AllMatching applies, the "default" action is always performed. 744 o Policy rules have a context in which they are executed. The rule 745 engine evaluates and applies the policy rules in the context of 746 the managed resource(s) that are identified by the policy roles 747 (or by an explicit association). Submodels MAY add additional 748 context to policy rules based on rule structure; any such 749 additional context is defined by the semantics of the action 750 classes of the submodel. 752 4.4.2. Motivation 754 Rule nesting enhances Policy readability, expressiveness and reusability. 755 The ability to nest policy rules and form sub-rules is important for 756 manageability and scalability, as it enables complex policy rules to be 757 constructed from multiple simpler policy rules. These enhancements ease 758 the policy management tools' task, allowing policy rules to be expressed 759 in a way closer to how humans think. 761 Although rule nesting can be used to suggest optimizations in the way 762 policy rules are evaluated, as discussed in section 4.5.2 "Side Effects," 763 nesting does not specify nor does it require any particular order of 764 evaluation of conditions. Optimization of rule evaluation can be done in 765 the PDP or in the PEP by dedicated code. This is similar to the relation 766 between a high level programming language like C and machine code. An 767 optimizer can create a more efficient machine code than any optimization 768 done by the programmer within the source code. Nevertheless, if the PEP 769 or PDP does not do optimization, the administrator writing the policy may 770 be able to influence the evaluation of the policy rules for execution 771 using rule nesting. 773 Nested rules are not designed for policy repository retrieval 774 optimization. It is assumed that all rules and groups that are assigned 775 to a role are retrieved by the PDP or PEP from the policy repository and 776 enforced. Optimizing the number of rules retrieved should be done by 777 clever selection of roles. 779 4.5. Priorities and Decision Strategies 781 A "decision strategy" is used to specify the evaluation method for the 782 policies in a PolicySet. Two decision strategies are defined: 783 "FirstMatching" and "AllMatching." The FirstMatching strategy is used to 784 cause the evaluation of the rules in a set such that the only actions 785 enforced on a given examination of the PolicySet are those for the first 786 rule (that is, the rule with the highest priority) that has its 787 conditions evaluate to TRUE. The AllMatching strategy is used to cause 788 the evaluation of all rules in a set; for all of the rules whose 789 conditions evaluate to TRUE, the actions are enforced. Implementations 790 MUST support the FirstMatching decision strategy; implementations MAY 791 support the AllMatching decision strategy. 793 As previously discussed, the PolicySet subclasses are PolicyGroup and 794 PolicyRule: either subclass may contain PolicySets of either subclass. 795 Loops, including the degenerate case of a PolicySet that contains itself, 796 are not allowed when PolicySets contain other PolicySets. The 797 containment relationship is specified using the PolicySetComponent 798 aggregation. 800 The relative priority within a PolicySet is established by the Priority 801 property of the PolicySetComponent aggregation of the contained 802 PolicyGroup and PolicyRule instances. The use of PCIM's 803 PolicyRule.Priority property is deprecated in favor of this new property. 804 The separation of the priority property from the rule has two advantages. 805 First, it generalizes the concept of priority, so that it can be used for 806 both groups and rules. Second, it places the priority on the 807 relationship between the parent policy set and the subordinate policy 808 group or rule. The assignment of a priority value then becomes much 809 easier, in that the value is used only in relationship to other 810 priorities in the same set. 812 Together, the PolicySet.PolicyDecisionStrategy and 813 PolicySetComponent.Priority determine the processing for the rules 814 contained in a PolicySet. As before, the larger priority value 815 represents the higher priority. Unlike the earlier definition, 816 PolicySetComponent.Priority MUST have a unique value when compared with 817 others defined for the same aggregating PolicySet. Thus, the evaluation 818 of rules within a set is deterministically specified. 820 For a FirstMatching decision strategy, the first rule (that is, the one 821 with the highest priority) in the set that evaluates to True, is the only 822 rule whose actions are enforced for a particular evaluation pass through 823 the PolicySet. 825 For an AllMatching decision strategy, all of the matching rules are 826 enforced. The relative priority of the rules is used to determine the 827 order in which the actions are to be executed by the enforcement point: 828 the actions of the higher priority rules are executed first. Since the 829 actions of higher priority rules are executed first, lower priority rules 830 that also match may get the "last word," and thus produce a counter- 831 intuitive result. So, for example, if two rules both evaluate to True, 832 and the higher priority rule sets the DSCP to 3 and the lower priority 833 rule sets the DSCP to 4, the action of the lower priority rule will be 834 executed later and, therefore, will "win," in this example, setting the 835 DSCP to 4. Thus, conflicts between rules are resolved by this execution 836 order. 838 An implementation of the rule engine need not provide the action 839 sequencing but the actions MUST be sequenced by the PEP or PDP on its 840 behalf. So, for example, the rule engine may provide an ordered list of 841 actions to be executed by the PEP and any required serialization is then 842 provided by the service configured by the rule engine. See section 4.5.2 843 for a discussion of side effects. 845 4.5.1. Structuring Decision Strategies 847 As discussed in Sections 4.3 and 4.4, PolicySet instances may be nested 848 arbitrarily. For a FirstMatching decision strategy on a PolicySet, any 849 contained PolicySet that matches satisfies the termination criteria for 850 the FirstMatching strategy. A PolicySet is considered to match if it is 851 a PolicyRule and its conditions evaluate to True, or if the PolicySet is 852 a PolicyGroup and at least one of its contained PolicyGroups or 853 PolicyRules match. The priority associated with contained PolicySets, 854 then, determines when to terminate rule evaluation in the structured set 855 of rules. 857 In the example shown in Figure 3, the relative priorities for the nested 858 rules, high to low, are 1A, 1B1, 1X2, 1B3, 1C, 1C1, 1X2 and 1C3. (Note 859 that PolicyRule 1X2 is included in both PolicyGroup 1B and PolicyRule 1C, 860 but with different priorities.) Of course, which rules are enforced is 861 also dependent on which rules, if any, match. 863 PolicyGroup 1: FirstMatching 864 | 865 +-- Pri=6 -- PolicyRule 1A 866 | 867 +-- Pri=5 -- PolicyGroup 1B: AllMatching 868 | | 869 | +-- Pri=5 -- PolicyGroup 1B1: AllMatching 870 | | | 871 | | +---- etc. 872 | | 873 | +-- Pri=4 -- PolicyRule 1X2 874 | | 875 | +-- Pri=3 -- PolicyRule 1B3: FirstMatching 876 | | 877 | +---- etc. 878 | 879 +-- Pri=4 -- PolicyRule 1C: FirstMatching 880 | 881 +-- Pri=4 -- PolicyRule 1C1 882 | 883 +-- Pri=3 -- PolicyRule 1X2 884 | 885 +-- Pri=2 -- PolicyRule 1C3 887 Figure 3. Nested PolicySets with Different Decision Strategies 889 o Because PolicyGroup 1 has a FirstMatching decision strategy, if 890 the conditions of PolicyRule 1A match, its actions are enforced 891 and the evaluation stops. 893 o If it does not match, PolicyGroup 1B is evaluated using an 894 AllMatching strategy. Since PolicyGroup 1B1 also has an 895 AllMatching strategy all of the rules and groups of rules 896 contained in PolicyGroup 1B1 are evaluated and enforced as 897 appropriate. PolicyRule 1X2 and PolicyRule 1B3 are also evaluated 898 and enforced as appropriate. If any of the sub-rules in the 899 subtrees of PolicyGroup 1B evaluate to True, then PolicyRule 1C is 900 not evaluated because the FirstMatching strategy of PolicyGroup 1 901 has been satisfied. 903 o If neither PolicyRule 1A nor PolicyGroup 1B yield a match, then 904 PolicyRule 1C is evaluated. Since it is first matching, rules 905 1C1, 1X2, and 1C3 are evaluated until the first match, if any. 907 4.5.2. Side Effects 909 Although evaluation of conditions is sometimes discussed as an ordered 910 set of operations, the rule engine need not be implemented as a 911 procedural language interpreter. Any side effects of condition evaluation 912 or the execution of actions MUST NOT affect the result of the evaluation 913 of other conditions evaluated by the rule engine in the same evaluation 914 pass. That is, an implementation of a rule engine MAY evaluate all 915 conditions in any order before applying the priority and determining 916 which actions are to be executed. 918 So, regardless of how a rule engine is implemented, it MUST NOT include 919 any side effects of condition evaluation in the evaluation of conditions 920 for either of the decision strategies. For both the AllMatching decision 921 strategy and for the nesting of rules within rules (either directly or 922 indirectly) where the actions of more than one rule may be enforced, any 923 side effects of the enforcement of actions MUST NOT be included in 924 condition evaluation on the same evaluation pass. 926 4.5.3. Multiple PolicySet Trees For a Resource 928 As shown in the example in Figure 3. , PolicySet trees are defined by the 929 PolicySet subclass instances and the PolicySetComponent aggregation 930 instances between them. Each PolicySet tree has a defined set of 931 decision strategies and evaluation priorities. In section 4.6 we discuss 932 some improvements in the use of PolicyRoles that cause the parent 933 PolicySet.PolicyRoles to be applied to all contained PolicySet instances. 934 However, a given resource may still have multiple, disjoint PolicySet 935 trees that are collected from different roles and role combinations. 936 These top-level PolicySet instances are called "unrooted". 938 A PolicySet instance is defined to be unrooted in the context of a 939 particular managed element; the relationship to the managed element is 940 usually established by the policy roles of the PolicySet instance and of 941 the managed element (see 4.6 "Policy Roles"). A PolicySet instance is 942 unrooted in that context if and only if there is no PolicySetComponent 943 association to a parent PolicySet that is also related to the same 944 managed element. Figure 4. shows an example where instance A has role A, 945 instance B has role B and so on. In this example, in the context of 946 interface X, B, and C are unrooted and, because roles are inherited, 947 instances D, E, and F are all rooted. 949 +---+ +-----------+ 950 | A | | I/F X | 951 +---+ | has roles | 952 / \ | B & C | 953 / \ +-----------+ 954 +---+ +---+ 955 | B | | C | 956 +---+ +---+ 957 / \ \ 958 / \ \ 959 +---+ +---+ +---+ 960 | D | | E | | F | 961 +---+ +---+ +---+ 963 Figure 4. Unrooted PolicySet Instances 965 For those cases where there are multiple unrooted PolicySet instances 966 that apply to the same managed resource (i.e., not in a common 967 PolicySetComponent tree), the decision strategy among these disjoint 968 PolicySet instances is the FirstMatching strategy. The priority used 969 with this FirstMatching strategy is defined in the PolicySetInSystem 970 association. 972 The FirstMatching strategy is used among all PolicySet instances that 973 apply to a given resource for a given functional domain. So, for 974 example, the PolicySet instances that are used for QOS policy and the 975 instances that are used for IKE policy, although they are disjoint, are 976 not joined in a FirstMatching decision strategy. Instead, they are 977 evaluated independently of one another. 979 4.5.4. Deterministic Decisions 981 As previously discussed, PolicySetComponent.Priority values MUST be 982 unique within a containing PolicySet and PolicySetInSystem.Priority 983 values MUST be unique for an associated System. Each PolicySet, then, has 984 a deterministic behavior based upon the decision strategy and uniquely 985 defined priority. 987 There are certainly cases where rules need not have a unique priority 988 value (i.e., where evaluation and execution priority is not important). 989 However, it is believed that the flexibility gained by this capability is 990 not sufficiently beneficial to justify the possible variations in 991 implementation behavior and the resulting confusion that might occur. 993 4.6. Policy Roles 995 A policy role is defined in [12] as "an administratively specified 996 characteristic of a managed element (for example, an interface). It is a 997 selector for policy rules and PRovisioning Classes (PRCs), to determine 998 the applicability of the rule/PRC to a particular managed element." 999 In PCIMe, PolicyRoles is defined as a property of PolicySet, which is 1000 inherited by both PolicyRules and PolicyGroups. In this draft, we also 1001 add PolicyRole as the identifying name of a collection of resources 1002 (PolicyRoleCollection), where each element in the collection has the 1003 specified role characteristic. 1005 4.6.1. Comparison of Roles in PCIM with Roles in snmpconf 1007 In the Configuration Management with SNMP (snmpconf) working group's 1008 Policy Based Management MIB [13], policy rules are of the form 1010 if then 1012 where is a set of conditions that are used to determine 1013 whether or not the policy applies to an object instance. The policy 1014 filter can perform comparison operations on SNMP variables already 1015 defined in MIBS (e.g., "ifType == ethernet"). 1017 The policy management MIB defined in [13] defines a Role table that 1018 enables one to associate Roles with elements, where roles have the same 1019 semantics as in PCIM. Then, since the policyFilter in a policy allows one 1020 to define conditions based on the comparison of the values of SNMP 1021 variables, one can filter elements based on their roles as defined in the 1022 Role group. 1024 This approach differs from that adopted in PCIM in the following ways. 1025 First, in PCIM, a set of role(s) is associated with a policy rule as the 1026 values of the PolicyRoles property of a policy rule. The semantics of 1027 role(s) are then expected to be implemented by the PDP (i.e. policies are 1028 applied to the elements with the appropriate roles). In [13], however, 1029 no special processing is required for realizing the semantics of roles; 1030 roles are treated just as any other SNMP variables and comparisons of 1031 role values can be included in the policy filter of a policy rule. 1033 Secondly, in PCIM, there is no formally defined way of associating a role 1034 with an object instance, whereas in [13] this is done via the use of the 1035 Role tables (pmRoleESTable and pmRoleSETable). The Role tables associate 1036 Role values with elements. 1038 4.6.2. Addition of PolicyRoleCollection to PCIMe 1040 In order to remedy the latter shortcoming in PCIM (the lack of a way of 1041 associating a role with an object instance), PCIMe has a new class 1042 PolicyRoleCollection derived from the CIM Collection class. Resources 1043 that share a common role are aggregated by a PolicyRoleCollection 1044 instance, via the ElementInPolicyRoleCollection aggregation. The role is 1045 specified in the PolicyRole property of the aggregating 1046 PolicyRoleCollection instance. 1048 A PolicyRoleCollection always exists in the context of a system. As was 1049 done in PCIM for PolicyRules and PolicyGroups, an association, 1050 PolicyRoleCollectionInSystem, captures this relationship. Remember that 1051 in CIM, System is a base class for describing network devices and 1052 administrative domains. 1054 The association between a PolicyRoleCollection and a system should be 1055 consistent with the associations that scope the policy rules/groups that 1056 are applied to the resources in that collection. Specifically, a 1057 PolicyRoleCollection should be associated with the same System as the 1058 applicable PolicyRules and/or PolicyGroups, or to a System higher in the 1059 tree formed by the SystemComponent association. When a PEP belongs to 1060 multiple Systems (i.e., AdminDomains), and scoping by a single domain is 1061 impractical, two alternatives exist. One is to arbitrarily limit domain 1062 membership to one System/AdminDomain. The other option is to define a 1063 more global AdminDomain that simply includes the others, and/or that 1064 spans the business or enterprise. 1066 As an example, suppose that there are 20 traffic trunks in a network, and 1067 that an administrator would like to assign three of them to provide 1068 "gold" service. Also, the administrator has defined several policy rules 1069 which specify how the "gold" service is delivered. For these rules, the 1070 PolicyRoles property (inherited from PolicySet) is set to "Gold Service". 1072 In order to associate three traffic trunks with "gold" service, an 1073 instance of the PolicyRoleCollection class is created and its PolicyRole 1074 property is also set to "Gold Service". Following this, the 1075 administrator associates three traffic trunks with the new instance of 1076 PolicyRoleCollection via the ElementInPolicyRoleCollection aggregation. 1077 This enables a PDP to determine that the "Gold Service" policy rules 1078 apply to the three aggregated traffic trunks. 1080 Note that roles are used to optimize policy retrieval. It is not 1081 mandatory to implement roles or, if they have been implemented, to group 1082 elements in a PolicyRoleCollection. However, if roles are used, then 1083 either the collection approach should be implemented, or elements should 1084 be capable of reporting their "pre-programmed" roles (as is done in 1085 COPS). 1087 4.6.3. Roles for PolicyGroups 1089 In PCIM, role(s) are only associated with policy rules. However, it may 1090 be desirable to associate role(s) with groups of policy rules. For 1091 example, a network administrator may want to define a group of rules that 1092 apply only to Ethernet interfaces. A policy group can be defined with a 1093 role-combination="Ethernet", and all the relevant policy rules can be 1094 placed in this policy group. (Note that in PCIMe, role(s) are made 1095 available to PolicyGroups as well as to PolicyRules by moving PCIM's 1096 PolicyRoles property up from PolicyRule to the new abstract class 1097 PolicySet. The property is then inherited by both PolicyGroup and 1098 PolicyRule.) Then every policy rule in this policy group implicitly 1099 inherits this role-combination from the containing policy group. A 1100 similar implicit inheritance applies to nested policy groups. 1102 There is no explicit copying of role(s) from container to contained 1103 entity. Obviously, this implicit inheritance of role(s) leads to the 1104 possibility of defining inconsistent role(s) (as explained in the example 1105 below); the handling of such inconsistencies is beyond the scope of 1106 PCIMe. 1108 As an example, suppose that there is a PolicyGroup PG1 that contains 1109 three PolicyRules, PR1, PR2, and PR3. Assume that PG1 has the roles 1110 "Ethernet" and "Fast". Also, assume that the contained policy rules have 1111 the role(s) shown below: 1113 +------------------------------+ 1114 | PolicyGroup PG1 | 1115 | PolicyRoles = Ethernet, Fast | 1116 +------------------------------+ 1117 | 1118 | +------------------------+ 1119 | | PolicyRule PR1 | 1120 |--------| PolicyRoles = Ethernet | 1121 | +------------------------+ 1122 | 1123 | +--------------------------+ 1124 | | PolicyRule PR2 | 1125 |--------| PolicyRoles = | 1126 | +--------------------------+ 1127 | 1128 | +------------------------+ 1129 | | PolicyRule PR3 | 1130 |--------| PolicyRoles = Slow | 1131 +------------------------+ 1133 Figure 5. Inheritance of Roles 1135 In this example, the PolicyRoles property value for PR1 is consistent 1136 with the value in PG1, and in fact, did not need to be redefined. The 1137 value of PolicyRoles for PR2 is undefined. Its roles are implicitly 1138 inherited from PG1. Lastly, the value of PolicyRoles for PR3 is "Slow". 1139 This appears to be in conflict with the role, "Fast," defined in PG1. 1140 However, whether these roles are actually in conflict is not clear. In 1141 one scenario, the policy administrator may have wanted only "Fast"- 1142 "Ethernet" rules in the policy group. In another scenario, the 1143 administrator may be indicating that PR3 applies to all "Ethernet" 1144 interfaces regardless of whether they are "Fast" or "Slow." Only in the 1145 former scenario (only "Fast"-"Ethernet" rules in the policy group) is 1146 there a role conflict. 1148 Note that it is possible to override implicitly inherited roles via 1149 appropriate conditions on a PolicyRule. For example, suppose that PR3 1150 above had defined the following conditions: 1152 (interface is not "Fast") and (interface is "Slow") 1153 This results in unambiguous semantics for PR3. 1155 4.7. Compound Policy Conditions and Compound Policy Actions 1157 Compound policy conditions and compound policy actions are introduced to 1158 provide additional reusable "chunks" of policy. 1160 4.7.1. Compound Policy Conditions 1162 A CompoundPolicyCondition is a PolicyCondition representing a Boolean 1163 combination of simpler conditions. The conditions being combined may be 1164 SimplePolicyConditions (discussed below in section 4.7), but the utility 1165 of reusable combinations of policy conditions is not necessarily limited 1166 to the case where the component conditions are simple ones. 1168 The PCIM extensions to introduce compound policy conditions are 1169 relatively straightforward. Since the purpose of the extension is to 1170 apply the DNF / CNF logic from PCIM's PolicyConditionInPolicyRule 1171 aggregation to a compound condition that aggregates simpler conditions, 1172 the following changes are required: 1174 o Create a new aggregation PolicyConditionInPolicyCondition, with the 1175 same GroupNumber and ConditionNegated properties as 1176 PolicyConditionInPolicyRule. The cleanest way to do this is to 1177 move the properties up to a new abstract aggregation superclass 1178 PolicyConditionStructure, from which the existing aggregation 1179 PolicyConditionInPolicyRule and a new aggregation 1180 PolicyConditionInPolicyCondition are derived. For now there is no 1181 need to re-document the properties themselves, since they are 1182 already documented in PCIM as part of the definition of the 1183 PolicyConditionInPolicyRule aggregation. 1184 o It is also necessary to define a concrete subclass 1185 CompoundPolicyCondition of PolicyCondition, to introduce the 1186 ConditionListType property. This property has the same function, 1187 and works in exactly the same way, as the corresponding property 1188 currently defined in PCIM for the PolicyRule class. 1190 The class and property definitions for representing compound policy 1191 conditions are below, in Section 5. 1193 4.7.2. Compound Policy Actions 1195 A compound action is a convenient construct to represent a sequence of 1196 actions to be applied as a single atomic action within a policy rule. In 1197 many cases, actions are related to each other and should be looked upon 1198 as sub-actions of one "logical" action. An example of such a logical 1199 action is "shape & mark" (i.e., shape a certain stream to a set of 1200 predefined bandwidth characteristics and then mark these packets with a 1201 certain DSCP value). This logical action is actually composed of two 1202 different QoS actions, which should be performed in a well-defined order 1203 and as a complete set. 1205 The CompoundPolicyAction construct allows one to create a logical 1206 relationship between a number of actions, and to define the activation 1207 logic associated with this logical action. 1209 The CompoundPolicyAction construct allows the reusability of these 1210 complex actions, by storing them in a ReusablePolicyContainer and reusing 1211 them in different policy rules. Note that a compound action may also be 1212 aggregated by another compound action. 1214 As was the case with CompoundPolicyCondition, the PCIM extensions to 1215 introduce compound policy actions are relatively straightforward. This 1216 time the goal is to apply the property ActionOrder from PCIM's 1217 PolicyActionInPolicyRule aggregation to a compound action that aggregates 1218 simpler actions. The following changes are required: 1220 o Create a new aggregation PolicyActionInPolicyAction, with the same 1221 ActionOrder property as PolicyActionInPolicyRule. The cleanest way 1222 to do this is to move the property up to a new abstract aggregation 1223 superclass PolicyActionStructure, from which the existing 1224 aggregation PolicyActionInPolicyRule and a new aggregation 1225 PolicyActionInPolicyAction are derived. 1226 o It is also necessary to define a concrete subclass 1227 CompoundPolicyAction of PolicyAction, to introduce the 1228 SequencedActions property. This property has the same function, 1229 and works in exactly the same way, as the corresponding property 1230 currently defined in PCIM for the PolicyRule class. 1231 o Finally, a new property ExecutionStrategy is needed for both the 1232 PCIM class PolicyRule and the new class CompoundPolicyAction. This 1233 property allows the policy administrator to specify how the PEP 1234 should behave in the case where there are multiple actions 1235 aggregated by a PolicyRule or by a CompoundPolicyAction. 1237 The class and property definitions for representing compound policy 1238 actions are below, in Section 5. 1240 4.8. Variables and Values 1242 The following subsections introduce several related concepts, including 1243 PolicyVariables and PolicyValues (and their numerous subclasses), 1244 SimplePolicyConditions, and SimplePolicyActions. 1246 4.8.1. Simple Policy Conditions 1248 The SimplePolicyCondition class models elementary Boolean expressions of 1249 the form: "( MATCH )". The relationship 'MATCH', which 1250 is implicit in the model, is interpreted based on the variable and the 1251 value. Section 4.8.3 explains the semantics of the 'MATCH' operator. 1252 Arbitrarily complex Boolean expressions can be formed by chaining 1253 together any number of simple conditions using relational operators. 1255 Individual simple conditions can be negated as well. Arbitrarily complex 1256 Boolean expressions are modeled by the class CompoundPolicyCondition 1257 (described in Section 4.7.1). 1259 For example, the expression "SourcePort == 80" can be modeled by a simple 1260 condition. In this example, 'SourcePort' is a variable, '==' is the 1261 relational operator denoting the equality relationship (which is 1262 generalized by PCIMe to a "MATCH" relationship), and '80' is an integer 1263 value. The complete interpretation of a simple condition depends on the 1264 binding of the variable. Section 4.8.5 describes variables and their 1265 binding rules. 1267 The SimplePolicyCondition class refines the basic structure of the 1268 PolicyCondition class defined in PCIM by using the pair (, 1269 ) to form the condition. Note that the operator between the 1270 variable and the value is always implied in PCIMe: it is not a part of 1271 the formal notation. 1273 The variable specifies the attribute of an object that should be matched 1274 when evaluating the condition. For example, for a QoS model, this object 1275 could represent the flow that is being conditioned. A set of predefined 1276 variables that cover network attributes commonly used for filtering is 1277 introduced in PCIMe, to encourage interoperability. This list covers 1278 layer 3 IP attributes such as IP network addresses, protocols and ports, 1279 as well as a set of layer 2 attributes (e.g., MAC addresses). 1281 The bound variable is matched against a value to produce the Boolean 1282 result. For example, in the condition "The source IP address of the flow 1283 belongs to the 10.1.x.x subnet", a source IP address variable is matched 1284 against a 10.1.x.x subnet value. 1286 4.8.2. Using Simple Policy Conditions 1288 Simple conditions can be used in policy rules directly, or as building 1289 blocks for creating compound policy conditions. 1291 Simple condition composition MUST enforce the following data-type 1292 conformance rule: The ValueTypes property of the variable must be 1293 compatible with the type of the value class used. The simplest (and 1294 friendliest, from a user point-of-view) way to do this is to equate the 1295 type of the value class with the name of the class. By ensuring that the 1296 ValueTypes property of the variable matches the name of the value class 1297 used, we know that the variable and value instance values are compatible 1298 with each other. 1300 Composing a simple condition requires that an instance of the class 1301 SimplePolicyCondition be created, and that instances of the variable and 1302 value classes that it uses also exist. Note that the variable and/or 1303 value instances may already exist as reusable objects in an appropriate 1304 ReusablePolicyContainer. 1306 Two aggregations are used in order to create the pair (, 1307 ). The aggregation PolicyVariableInSimplePolicyCondition relates 1308 a SimplePolicyCondition to a single variable instance. Similarly, the 1309 aggregation PolicyValueInSimplePolicyCondition relates a 1310 SimplePolicyCondition to a single value instance. Both aggregations are 1311 defined in this document. 1313 Figure 6. depicts a SimplePolicyCondition with its associated variable 1314 and value. Also shown are two PolicyValue instances that identify the 1315 values that the variable can assume. 1317 +-----------------------+ 1318 | SimplePolicyCondition | 1319 +-----------------------+ 1320 * @ 1321 * @ 1322 +------------------+ * @ +---------------+ 1323 | (PolicyVariable) |*** @@@| (PolicyValue) | 1324 +------------------+ +---------------+ 1325 # # 1326 # ooo # 1327 # # 1328 +---------------+ +---------------+ 1329 | (PolicyValue) | ooo | (PolicyValue) | 1330 +---------------+ +---------------+ 1332 Aggregation Legend: 1333 **** PolicyVariableInSimplePolicyCondition 1334 @@@@ PolicyValueInSimplePolicyCondition 1335 #### ExpectedPolicyValuesForVariable 1337 Figure 6. SimplePolicyCondition 1339 Note: The class names in parenthesis denote subclasses. The classes 1340 named in the figure are abstract, and thus cannot themselves be 1341 instantiated. 1343 4.8.3. The Simple Condition Operator 1345 A simple condition models an elementary Boolean expression of the form 1346 "variable MATCHes value". However, the formal notation of the 1347 SimplePolicyCondition, together with its associations, models only a 1348 pair, (, ). The 'MATCH' operator is not directly 1349 modeled -- it is implied. Furthermore, this implied 'MATCH' operator 1350 carries overloaded semantics. 1352 For example, in the simple condition "DestinationPort MATCH '80'", the 1353 interpretation of the 'MATCH' operator is equality (the 'equal' 1354 operator). Clearly, a different interpretation is needed in the 1355 following cases: 1357 o "DestinationPort MATCH {'80', '8080'}" -- operator is 'IS SET 1358 MEMBER' 1360 o "DestinationPort MATCH {'1 to 255'}" -- operator is 'IN INTEGER 1361 RANGE' 1363 o "SourceIPAddress MATCH 'MyCompany.com'" -- operator is 'IP ADDRESS 1364 AS RESOLVED BY DNS' 1366 The examples above illustrate the implicit, context-dependant nature of 1367 the 'MATCH' operator. The interpretation depends on the actual variable 1368 and value instances in the simple condition. The interpretation is 1369 always derived from the bound variable and the value instance associated 1370 with the simple condition. Text accompanying the value class and 1371 implicit variable definition is used for interpreting the semantics of 1372 the 'MATCH' relationship. In the following list, we define generic 1373 (type-independent) matching. 1375 PolicyValues may be multi-fielded, where each field may contain a range 1376 of values. The same equally holds for PolicyVariables. Basically, we 1377 have to deal with single values (singleton), ranges ([lower bound .. 1378 upper bound]), and sets (a,b,c). So independent of the variable and 1379 value type, the following set of generic matching rules for the 'MATCH' 1380 operator are defined. 1382 o singleton matches singleton -> the matching rule is defined in the 1383 type 1385 o singleton matches range [lower bound .. upper bound] -> the 1386 matching evaluates to true, if the singleton matches the lower 1387 bound or the upper bound or a value in between 1389 o singleton matches set -> the matching evaluates to true, if the 1390 value of the singleton matches one of the components in the set, 1391 where a component may be a singleton or range again 1393 o ranges [A..B] matches singleton -> is true if A matches B matches 1394 singleton 1396 o range [A..B] matches range [X..Y] -> the matching evaluates to 1397 true, if all values of the range [A..B] are also in the range 1398 [X..Y]. For instance, [3..5] match [1..6] evaluates to true, 1399 whereas [3..5] match [4..6] evaluates to false. 1401 o range [A..B] matches set (a,b,c, ...) -> the matching evaluates to 1402 true, if all values in the range [A..B] are part of the set. For 1403 instance, range [2..3] match set ([1..2],3) evaluates to true, as 1404 well as range [2..3] match set (2,3), and range [2..3] match set 1405 ([1..2],[3..5]). 1407 o set (a,b,c, ...) match singleton -> is true if a match b match c 1408 match ... match singleton 1409 o set match range -> the matching evaluates to true, if all values 1410 in the set are part of the range. For example, set (2,3) match 1411 range [1..4] evaluates to true. 1413 o set (a,b,c,...) match set (x,y,z,...) -> the matching evaluates to 1414 true, if all values in the set (a,b,c,...) are part of the set 1415 (x,y,z,...). For example, set (1,2,3) match set (1,2,3,4) 1416 evaluates to true. Set (1,2,3) match set (1,2) evaluates to 1417 false. 1419 Variables may contain various types (section 5.11.1). When not stated 1420 otherwise, the type of the value bound to the variable at condition 1421 evaluation time and the value type of the PolicyValue instance need to be 1422 of the same type. If they differ, then the condition evaluates to FALSE. 1424 The ExpectedPolicyValuesForVariable association specifies an expected set 1425 of values that can be matched with a variable within a simple condition. 1426 Using this association, a source or destination port can be limited to 1427 the range 0-200, a source or destination IP address can be limited to a 1428 specified list of IPv4 address values, etc. 1430 +-----------------------+ 1431 | SimplePolicyCondition | 1432 +-----------------------+ 1433 * @ 1434 * @ 1435 * @ 1436 +-----------------------------------+ +--------------------------+ 1437 | Name=SmallSourcePorts | | Name=Port300 | 1438 | Class=PolicySourcePortVariable | | Class=PolicyIntegerValue | 1439 | ValueTypes=[PolicyIntegerVariable]| | IntegerList = [300] | 1440 +-----------------------------------+ +--------------------------+ 1441 # 1442 # 1443 # 1444 +-------------------------+ 1445 |Name=SmallPortsValues | 1446 |Class=PolicyIntegerValue | 1447 |IntegerList=[1..200] | 1448 +-------------------------+ 1450 Aggregation Legend: 1451 **** PolicyVariableInSimplePolicyCondition 1452 @@@@ PolicyValueInSimplePolicyCondition 1453 #### ExpectedPolicyValuesForVariable 1455 Figure 7. An Invalid SimplePolicyCondition 1457 The ability to express these limitations appears in the model to support 1458 validation of a SimplePolicyCondition prior to its deployment to an 1459 enforcement point. A Policy Management Tool, for example SHOULD NOT 1460 accept the SimplePolicyCondition shown in Figure 7. If, however, a 1461 policy rule containing this condition does appear at an enforcement 1462 point, the expected values play no role in the determination of whether 1463 the condition evaluates to True or False. Thus in this example, the 1464 SimplePolicyCondition evaluates to True if the source port for the packet 1465 under consideration is 300, and it evaluates to False otherwise. 1467 4.8.4. SimplePolicyActions 1469 The SimplePolicyAction class models the elementary set operation. "SET 1470 TO ". The set operator MUST overwrite an old value of 1471 the variable. In the case where the variable to be updated is multi- 1472 valued, the only update operation defined is a complete replacement of 1473 all previous values with a new set. In other words, there are no Add or 1474 Remove [to/from the set of values] operations defined for 1475 SimplePolicyActions. 1477 For example, the action "set DSCP to EF" can be modeled by a simple 1478 action. In this example, 'DSCP' is an implicit variable referring to the 1479 IP packet header DSCP field. 'EF' is an integer or bit string value (6 1480 bits). The complete interpretation of a simple action depends on the 1481 binding of the variable. 1483 The SimplePolicyAction class refines the basic structure of the 1484 PolicyAction class defined in PCIM, by specifying the contents of the 1485 action using the (, ) pair to form the action. The 1486 variable specifies the attribute of an object. The value of this 1487 attribute is set to the value specified in . Selection of the 1488 object is a function of the type of variable involved. See Sections 1489 4.8.6 and 4.8.7, respectively, for details on object selection for 1490 explicitly bound and implicitly bound policy variables. 1492 SimplePolicyActions can be used in policy rules directly, or as building 1493 blocks for creating CompoundPolicyActions. 1495 The set operation is only valid if the list of types of the variable 1496 (ValueTypes property of PolicyImplicitVariable) includes the specified 1497 type of the value. Conversion of values from one representation into 1498 another is not defined. For example, a variable of IPv4Address type may 1499 not be set to a string containing a DNS name. Conversions are part of an 1500 implementation-specific mapping of the model. 1502 As was the case with SimplePolicyConditions, the role of expected values 1503 for the variables that appear in SimplePolicyActions is for validation, 1504 prior to the time when an action is executed. Expected values play no 1505 role in action execution. 1507 Composing a simple action requires that an instance of the class 1508 SimplePolicyAction be created, and that instances of the variable and 1509 value classes that it uses also exist. Note that the variable and/or 1510 value instances may already exist as reusable objects in an appropriate 1511 ReusablePolicyContainer. 1513 Two aggregations are used in order to create the pair (, 1514 ). The aggregation PolicyVariableInSimplePolicyAction relates a 1515 SimplePolicyAction to a single variable instance. Similarly, the 1516 aggregation PolicyValueInSimplePolicyAction relates a SimplePolicyAction 1517 to a single value instance. Both aggregations are defined in this 1518 document. 1520 Figure 8. depicts a SimplePolicyAction with its associated variable and 1521 value. 1523 +-----------------------+ 1524 | SimplePolicyAction | 1525 | | 1526 +-----------------------+ 1527 * @ 1528 * @ 1529 +------------------+ * @ +---------------+ 1530 | (PolicyVariable) |*** @@@| (PolicyValue) | 1531 +------------------+ +---------------+ 1532 # # 1533 # ooo # 1534 # # 1535 +---------------+ +---------------+ 1536 | (PolicyValue) | ooo | (PolicyValue) | 1537 +---------------+ +---------------+ 1539 Aggregation Legend: 1540 **** PolicyVariableInSimplePolicyAction 1541 @@@@ PolicyValueInSimplePolicyAction 1542 #### ExpectedPolicyValuesForVariable 1544 Figure 8. SimplePolicyAction 1546 4.8.5. Policy Variables 1548 A variable generically represents information that changes (or "varies"), 1549 and that is set or evaluated by software. In policy, conditions and 1550 actions can abstract information as "policy variables" to be evaluated in 1551 logical expressions, or set by actions. 1553 PCIMe defines two types of PolicyVariables, PolicyImplicitVariables and 1554 PolicyExplicitVariables. The semantic difference between these classes 1555 is based on modeling context. Explicit variables are bound to exact 1556 model constructs, while implicit variables are defined and evaluated 1557 outside of a model. For example, one can imagine a PolicyCondition 1558 testing whether a CIM ManagedSystemElement's Status property has the 1559 value "Error." The Status property is an explicitly defined 1560 PolicyVariable (i.e., it is defined in the context of the CIM Schema, and 1561 evaluated in the context of a specific instance). On the other hand, 1562 network packets are not explicitly modeled or instantiated, since there 1563 is no perceived value (at this time) in managing at the packet level. 1564 Therefore, a PolicyCondition can make no explicit reference to a model 1565 construct that represents a network packet's source address. In this 1566 case, an implicit PolicyVariable is defined, to allow evaluation or 1567 modification of a packet's source address. 1569 4.8.6. Explicitly Bound Policy Variables 1571 Explicitly bound policy variables indicate the class and property names 1572 of the model construct to be evaluated or set. The CIM Schema defines 1573 and constrains "appropriate" values for the variable (i.e., model 1574 property) using data types and other information such as class/property 1575 qualifiers. 1577 A PolicyExplicitVariable is "explicit" because its model semantics are 1578 exactly defined. It is NOT explicit due to an exact binding to a 1579 particular object instance. If PolicyExplicitVariables were tied to 1580 instances (either via associations or by an object identification 1581 property in the class itself), then we would be forcing element-specific 1582 rules. On the other hand, if we only specify the object's model context 1583 (class and property name), but leave the binding to the policy framework 1584 (for example, using policy roles), then greater flexibility results for 1585 either general or element-specific rules. 1587 For example, an element-specific rule is obtained by a condition 1588 ((, ) pair) that defines CIM LogicalDevice 1589 DeviceID="12345". Alternately, if a PolicyRule's PolicyRoles is "edge 1590 device" and the condition ((, ) pair) is Status="Error", 1591 then a general rule results for all edge devices in error. 1593 Currently, the only binding for a PolicyExplicitVariable defined in PCIMe 1594 is to the instances selected by policy roles. For each such instance, a 1595 SimplePolicyCondition that aggregates the PolicyExplicitVariable 1596 evaluates to True if and only if ALL of the following are true: 1598 o The instance selected is of the class identified by the variable's 1599 ModelClass property, or of a subclass of this class. 1600 o The instance selected has the property identified by the 1601 variable's ModelProperty property. 1602 o The value of this property in the instance matches the value 1603 specified in the PolicyValue aggregated by the condition. 1605 In all other cases, the SimplePolicyCondition evaluates to False. 1607 For the case where a SimplePolicyAction aggregates a 1608 PolicyExplicitVariable, the indicated property in the selected instance 1609 is set to the value represented by the PolicyValue that the 1610 SimplePolicyAction also aggregates. However, if the selected instance is 1611 not of the class identified by the variable's ModelClass property, or of 1612 a subclass of this class, then the action is not performed. In this case 1613 the SimplePolicyAction is not treated either as a successfully executed 1614 action (for the execution strategy Do Until Success) or as a failed 1615 action (for the execution strategy Do Until Failure). Instead, the 1616 remaining actions for the policy rule, if any, are executed as if this 1617 SimplePolicyAction were not present at all in the list of actions 1618 aggregated by the rule. 1620 Explicit variables would be more powerful if they could reach beyond the 1621 instances selected by policy roles, to related instances. However, to 1622 represent a policy rule involving such variables in any kind of general 1623 way requires something that starts to resemble very much a complete 1624 policy language. Clearly such a language is outside the scope of PCIMe, 1625 although it might be the subject of a future draft. 1627 By restricting much of the generality, it would be possible for explicit 1628 variables in PCIMe to reach slightly beyond a selected instance. For 1629 example, if a selected instance were related to exactly one instance of 1630 another class via a particular association class, and if the goal of the 1631 policy rule were both to test a property of this related instance and to 1632 set a property of that same instance, then it would be possible to 1633 represent the condition and action of the rule using 1634 PolicyExplicitVariables. Rather than handling this one specific case 1635 with explicit variables, though, it was decided to lump them with the 1636 more general case, and deal with them if and when a policy language is 1637 defined. 1639 Refer to Section 5.10 for the formal definition of the class 1640 PolicyExplicitVariable. 1642 4.8.7. Implicitly Bound Policy Variables 1644 Implicitly bound policy variables define the data type and semantics of a 1645 variable. This determines how the variable is bound to a value in a 1646 condition or an action. Further instructions are provided for specifying 1647 data type and/or value constraints for implicitly bound variables. 1649 PCIMe introduces an abstract class, PolicyImplicitVariable, to model 1650 implicitly bound variables. This class is derived from the abstract 1651 class PolicyVariable also defined in PCIMe. Each of the implicitly bound 1652 variables introduced by PCIMe (and those that are introduced by domain- 1653 specific sub-models) MUST be derived from the PolicyImplicitVariable 1654 class. The rationale for using this mechanism for modeling is explained 1655 below in Section 4.8.9. 1657 A domain-specific policy information model that extends PCIMe may define 1658 additional implicitly bound variables either by deriving them directly 1659 from the class PolicyImplicitVariable, or by further refining an existing 1660 variable class such as SourcePort. When refining a class such as 1661 SourcePort, existing binding rules, type or value constraints may be 1662 narrowed. 1664 4.8.8. Structure and Usage of Pre-Defined Variables 1666 A class derived from PolicyImplicitVariable to model a particular 1667 implicitly bound variable SHOULD be constructed so that its name depicts 1668 the meaning of the variable. For example, a class defined to model the 1669 source port of a TCP/UDP flow SHOULD have 'SourcePort' in its name. 1671 PCIMe defines one association and one general-purpose mechanism that 1672 together characterize each of the implicitly bound variables that it 1673 introduces: 1675 1. The ExpectedPolicyValuesForVariable association defines the set of 1676 value classes that could be matched to this variable. 1678 2. The list of constraints on the values that the PolicyVariable can 1679 hold (i.e., values that the variable must match) are defined by 1680 the appropriate properties of an associated PolicyValue class. 1682 In the example presented above, a PolicyImplicitVariable represents the 1683 SourcePort of incoming traffic. The ValueTypes property of an instance 1684 of this class will hold the class name PolicyIntegerValue. This by 1685 itself constrains the data type of the SourcePort instance to be an 1686 integer. However, we can further constrain the particular values that 1687 the SourcePort variable can hold by entering valid ranges in the 1688 IntegerList property of the PolicyIntegerValue instance (0 - 65535 in 1689 this document). 1691 The combination of the VariableName and the 1692 ExpectedPolicyValuesForVariable association provide a consistent and 1693 extensible set of metadata that define the semantics of variables that 1694 are used to form policy conditions. Since the 1695 ExpectedPolicyValuesForVariable association points to a PolicyValue 1696 instance, any of the values expressible in the PolicyValue class can be 1697 used to constrain values that the PolicyImplicitVariable can hold. For 1698 example: 1700 o The ValueTypes property can be used to ensure that only proper 1701 classes are used in the expression. For example, the SourcePort 1702 variable will not be allowed to ever be of type 1703 PolicyIPv4AddrValue, since source ports have different semantics 1704 than IP addresses and may not be matched. However, integer value 1705 types are allowed as the property ValueTypes holds the string 1706 "PolicyIntegerValue", which is the class name for integer values. 1708 o The ExpectedPolicyValuesForVariable association also ensures that 1709 variable-specific semantics are enforced (e.g., the SourcePort 1710 variable may include a constraint association to a value object 1711 defining a specific integer range that should be matched). 1713 4.8.9. Rationale for Modeling Implicit Variables as Classes 1715 An implicitly bound variable can be modeled in one of several ways, 1716 including a single class with an enumerator for each individual 1717 implicitly bound variable and an abstract class extended for each 1718 individual variable. The reasons for using a class inheritance mechanism 1719 for specifying individual implicitly bound variables are these: 1721 1. It is easy to extend. A domain-specific information model can 1722 easily extend the PolicyImplicitVariable class or its subclasses 1723 to define domain-specific and context-specific variables. For 1724 example, a domain-specific QoS policy information model may 1725 introduce an implicitly bound variable class to model applications 1726 by deriving a qosApplicationVariable class from the 1727 PolicyImplicitVariable abstract class. 1729 2. Introduction of a single structural class for implicitly bound 1730 variables would have to include an enumerator property that 1731 contains all possible individual implicitly bound variables. This 1732 means that a domain-specific information model wishing to 1733 introduce an implicitly bound variable must extend the enumerator 1734 itself. This results in multiple definitions of the same class, 1735 differing in the values available in the enumerator class. One 1736 definition, in this document, would include the common implicitly 1737 bound variables' names, while a second definition, in the domain- 1738 specific information model document, may include additional values 1739 ('qosApplicationVariable' in the example above). It wouldn�t even 1740 be obvious to the application developer that multiple class 1741 definitions existed. It would be harder still for the application 1742 developer to actually find the correct class to use. 1744 3. In addition, an enumerator-based definition would require each 1745 additional value to be registered with IANA to ascertain adherence 1746 to standards. This would make the process cumbersome. 1748 4. A possible argument against the inheritance mechanism would cite 1749 the fact that this approach results in an explosion of class 1750 definitions compared to an enumerator class, which only introduces 1751 a single class. While, by itself, this is not a strike against 1752 the approach, it may be argued that data models derived from this 1753 information model may be more difficult to optimize for 1754 applications. This argument is rejected on the grounds that 1755 application optimization is of lesser value for an information 1756 model than clarity and ease of extension. In addition, it is hard 1757 to claim that the inheritance model places an absolute burden on 1758 the optimization. For example, a data model may still use 1759 enumeration to denote instances of pre-defined variables and claim 1760 PCIMe compliance, as long as the data model can be mapped 1761 correctly to the definitions specified in this document. 1763 4.8.10. Policy Values 1765 The abstract class PolicyValue is used for modeling values and constants 1766 used in policy conditions. Different value types are derived from this 1767 class, to represent the various attributes required. Extensions of the 1768 abstract class PolicyValue, defined in this document, provide a list of 1769 values for basic network attributes. Values can be used to represent 1770 constants as named values. Named values can be kept in a reusable policy 1771 container to be reused by multiple conditions. Examples of constants 1772 include well-known ports, well-known protocols, server addresses, and 1773 other similar concepts. 1775 The PolicyValue subclasses define three basic types of values: scalars, 1776 ranges and sets. For example, a well-known port number could be defined 1777 using the PolicyIntegerValue class, defining a single value (80 for 1778 HTTP), a range (80-88), or a set (80, 82, 8080) of ports, respectively. 1779 For details, please see the class definition for each value type in 1780 Section 5.14 of this document. 1782 PCIMe defines the following subclasses of the abstract class PolicyValue: 1784 Classes for general use: 1786 - PolicyStringValue, 1787 - PolicyIntegerValue, 1788 - PolicyBitStringValue 1789 - PolicyBooleanValue. 1791 Classes for layer 3 Network values: 1793 - PolicyIPv4AddrValue, 1794 - PolicyIPv6AddrValue. 1796 Classes for layer 2 Network values: 1798 - PolicyMACAddrValue. 1800 For details, please see the class definition section of each class in 1801 Section 5.14 of this document. 1803 4.9. Packet Filtering 1805 PCIMe contains two mechanisms for representing packet filters. The more 1806 general of these, termed here the domain-level model, expresses packet 1807 filters in terms of policy variables and policy values. The other 1808 mechanism, termed here the device-level model, expresses packet filters 1809 in a way that maps more directly to the packet fields to which the 1810 filters are being applied. While it is possible to map between these two 1811 representations of packet filters, no mapping is provided in PCIMe 1812 itself. 1814 4.9.1. Domain-Level Packet Filters 1816 In addition to filling in the holes in the overall Policy infrastructure, 1817 PCIMe proposes a single mechanism for expressing domain-level packet 1818 filters in policy conditions. This is being done in response to concerns 1819 that even though the initial "wave" of submodels derived from PCIM were 1820 all filtering on IP packets, each was doing it in a slightly different 1821 way. PCIMe proposes a common way to express IP packet filters. The 1822 following figure illustrates how packet-filtering conditions are 1823 expressed in PCIMe. 1825 +---------------------------------+ 1826 | CompoundFilterCondition | 1827 | - IsMirrored boolean | 1828 | - ConditionListType (DNF|CNF) | 1829 +---------------------------------+ 1830 + + + 1831 + + + 1832 + + + 1833 SimplePC SimplePC SimplePC 1834 * @ * @ * @ 1835 * @ * @ * @ 1836 * @ * @ * @ 1837 FlowDirection "In" SrcIP DstIP 1839 Aggregation Legend: 1840 ++++ PolicyConditionInPolicyCondition 1841 **** PolicyVariableInSimplePolicyCondition 1842 @@@@ PolicyValueInSimplePolicyCondition 1844 Figure 9. Packet Filtering in Policy Conditions 1846 In Figure 9. , each SimplePolicyCondition represents a single field to be 1847 filtered on: Source IP address, Destination IP address, Source port, etc. 1848 An additional SimplePolicyCondition indicates the direction that a packet 1849 is traveling on an interface: inbound or outbound. Because of the 1850 FlowDirection condition, care must be taken in aggregating a set of 1851 SimplePolicyConditions into a CompoundFilterCondition. Otherwise, the 1852 resulting CompoundPolicyCondition may match all inbound packets, or all 1853 outbound packets, when this is probably not what was intended. 1855 Individual SimplePolicyConditions may be negated when they are aggregated 1856 by a CompoundFilterCondition. 1858 CompoundFilterCondition is a subclass of CompoundPolicyCondition. It 1859 introduces one additional property, the Boolean property IsMirrored. The 1860 purpose of this property is to allow a single CompoundFilterCondition to 1861 match packets traveling in both directions on a higher-level connection 1862 such as a TCP session. When this property is TRUE, additional packets 1863 match a filter, beyond those that would ordinarily match it. An example 1864 will illustrate how this property works. 1866 Suppose we have a CompoundFilterCondition that aggregates the following 1867 three filters, which are ANDed together: 1869 o FlowDirection = "In" 1870 o Source IP = 9.1.1.1 1871 o Source Port = 80 1873 Regardless of whether IsMirrored is TRUE or FALSE, inbound packets will 1874 match this CompoundFilterCondition if their Source IP address = 9.1.1.1 1875 and their Source port = 80. If IsMirrored is TRUE, however, an outbound 1876 packet will also match the CompoundFilterCondition if its Destination IP 1877 address = 9.1.1.1 and its Destination port = 80. 1879 IsMirrored "flips" the following Source/Destination packet header fields: 1881 o FlowDirection "In" / FlowDirection "Out" 1882 o Source IP address / Destination IP address 1883 o Source port / Destination port 1884 o Source MAC address / Destination MAC address 1885 o Source [layer-2] SAP / Destination [layer-2] SAP. 1887 4.9.2. Device-Level Packet Filters 1889 At the device level, packet header filters are represented by two 1890 subclasses of the abstract class FilterEntryBase: IpHeadersFilter and 1891 8021Filter. Submodels of PCIMe may define other subclasses of 1892 FilterEntryBase in addition to these two; ICPM [6], for example, defines 1893 subclasses for IPsec-specific filters. 1895 Instances of the subclasses of FilterEntryBase are not used directly as 1896 filters. They are always aggregated into a FilterList, by the 1897 aggregation EntriesInFilterList. For PCIMe and its submodels, the 1898 EntrySequence property in this aggregation always takes its default value 1899 '0', indicating that the aggregated filter entries are ANDed together. 1901 The FilterList class includes an enumeration property Direction, 1902 representing the direction of the traffic flow to which the FilterList is 1903 to be applied. The value Mirrored(4) for Direction represents exactly 1904 the same thing as the IsMirrored boolean does in CompoundFilterCondition. 1905 See Section 4.9.1 for details. 1907 4.10. Conformance to PCIM and PCIMe 1909 Because PCIM and PCIMe provide the core classes for modeling policies, 1910 they are not in general sufficient by themselves for representing actual 1911 policy rules. Submodels, such as QPIM and ICPM, provide the means for 1912 expressing policy rules, by defining subclasses of the classes defined in 1913 PCIM and PCIMe, and/or by indicating how the PolicyVariables and 1914 PolicyValues defined in PCIMe can be used to express conditions and 1915 actions applicable to the submodel. 1917 A particular submodel will not, in general, need to use every element 1918 defined in PCIM and PCIMe. For the elements it does not use, a submodel 1919 SHOULD remain silent on whether its implementations must support the 1920 element, must not support the element, should support the element, etc. 1921 For the elements it does use, a submodel SHOULD indicate which elements 1922 its implementations must support, which elements they should support, and 1923 which elements they may support. 1925 PCIM and PCIMe themselves simply define elements that may be of use to 1926 submodels. These documents remain silent on whether implementations are 1927 required to support an element, should support it, etc. 1929 This model (and derived submodels) defines conditions and actions that 1930 are used by policy rules. While the conditions and actions defined 1931 herein are straightforward and may be presumed to be widely supported, as 1932 submodels are developed it is likely that situations will arise in which 1933 specific conditions or actions are not supported by some part of the 1934 policy execution system. Similarly, situations may also occur where 1935 rules contain syntactic or semantic errors. 1937 It should be understood that the behavior and effect of undefined or 1938 incorrectly defined conditions or actions is not prescribed by this 1939 information model. While it would be helpful if it were prescribed, the 1940 variations in implementation restrict the ability for this information 1941 model to control the effect. For example, if an implementation only 1942 detected that a PEP could not enforce a given action on that PEP, it 1943 would be very difficult to declare that such a failure should affect 1944 other PEPs, or the PDP process. On the other hand, if the PDP determines 1945 that it cannot properly evaluate a condition, that failure may well 1946 affect all applications of the containing rules. 1948 5. Class Definitions 1950 The following definitions supplement those in PCIM itself. PCIM 1951 definitions that are not DEPRECATED here are still current parts of the 1952 overall Policy Core Information Model. 1954 5.1. The Abstract Class "PolicySet" 1956 PolicySet is an abstract class that may group policies into a structured 1957 set of policies. 1959 NAME PolicySet 1960 DESCRIPTION An abstract class that represents a set of policies 1961 that form a coherent set. The set of contained 1962 policies has a common decision strategy and a common 1963 set of policy roles. Subclasses include PolicyGroup 1964 and PolicyRule. 1965 DERIVED FROM Policy 1966 ABSTRACT TRUE 1967 PROPERTIES PolicyDecisionStrategy 1968 PolicyRoles 1970 The PolicyDecisionStrategy property specifies the evaluation method for 1971 policy groups and rules contained within the policy set. 1973 NAME PolicyDecisionStrategy 1974 DESCRIPTION The evaluation method used for policies contained in 1975 the PolicySet. FirstMatching enforces the actions of 1976 the first rule that evaluates to TRUE; AllMatching 1977 enforces the actions of all rules that evaluate to 1978 TRUE. 1979 SYNTAX uint16 1980 VALUES 1 [FirstMatching], 2 [AllMatching] 1981 DEFAULT VALUE 1 [FirstMatching] 1983 The definition of PolicyRoles is unchanged from PCIM. It is, however, 1984 moved from the class Policy up to the superclass PolicySet. 1986 5.2. Update PCIM's Class "PolicyGroup" 1988 The PolicyGroup class is moved, so that it is now derived from PolicySet. 1990 NAME PolicyGroup 1991 DESCRIPTION A container for a set of related PolicyRules and 1992 PolicyGroups. 1993 DERIVED FROM PolicySet 1994 ABSTRACT FALSE 1995 PROPERTIES (none) 1997 5.3. Update PCIM's Class "PolicyRule" 1999 The PolicyRule class is moved, so that it is now derived from PolicySet. 2000 The Priority property is also deprecated in PolicyRule, and PolicyRoles 2001 is now inherited from the parent class PolicySet. Finally, a new 2002 property ExecutionStrategy is introduced, paralleling the property of the 2003 same name in the class CompoundPolicyAction. 2005 NAME PolicyRule 2006 DESCRIPTION The central class for representing the "If Condition 2007 then Action" semantics associated with a policy rule. 2008 DERIVED FROM PolicySet 2009 ABSTRACT FALSE 2010 PROPERTIES Enabled 2011 ConditionListType 2012 RuleUsage 2013 Priority DEPRECATED FOR PolicySetComponent.Priority 2014 AND FOR PolicySetInSystem.Priority 2015 Mandatory 2016 SequencedActions 2017 ExecutionStrategy 2019 The property ExecutionStrategy defines the execution strategy to be used 2020 upon the sequenced actions aggregated by this PolicyRule. (An equivalent 2021 ExecutionStrategy property is also defined for the CompoundPolicyAction 2022 class, to provide the same indication for the sequenced actions 2023 aggregated by a CompoundPolicyAction.) This draft defines three 2024 execution strategies: 2026 Do Until Success � execute actions according to predefined order, until 2027 successful execution of a single action. 2028 Do All - execute ALL actions which are part of the modeled 2029 set, according to their predefined order. Continue 2030 doing this, even if one or more of the actions 2031 fails. 2033 Do Until Failure - execute actions according to predefined order, until 2034 the first failure in execution of a single sub- 2035 action. 2037 The property definition is as follows: 2039 NAME ExecutionStrategy 2040 DESCRIPTION An enumeration indicating how to interpret the action 2041 ordering for the actions aggregated by this 2042 PolicyRule. 2043 SYNTAX uint16 (ENUM, {1=Do Until Success, 2=Do All, 3=Do 2044 Until Failure} ) 2045 DEFAULT VALUE Do All (2) 2047 5.4. The Class "SimplePolicyCondition" 2049 A simple policy condition is composed of an ordered triplet: 2051 MATCH 2053 No formal modeling of the MATCH operator is provided. The 'match' 2054 relationship is implied. Such simple conditions are evaluated by 2055 answering the question: 2057 Does match ? 2059 The 'match' relationship is to be interpreted by analyzing the variable 2060 and value instances associated with the simple condition. 2062 Simple conditions are building blocks for more complex Boolean 2063 Conditions, modeled by the CompoundPolicyCondition class. 2065 The SimplePolicyCondition class is derived from the PolicyCondition class 2066 defined in PCIM. 2068 A variable and a value must be associated with a simple condition to make 2069 it a meaningful condition, using, respectively, the aggregations 2070 PolicyVariableInSimplePolicyCondition and 2071 PolicyValueInSimplePolicyCondition. 2073 The class definition is as follows: 2075 NAME SimplePolicyCondition 2076 DERIVED FROM PolicyCondition 2077 ABSTRACT False 2078 PROPERTIES (none) 2080 5.5. The Class "CompoundPolicyCondition" 2082 This class represents a compound policy condition, formed by aggregation 2083 of simpler policy conditions. 2085 NAME CompoundPolicyCondition 2086 DESCRIPTION A subclass of PolicyCondition that introduces the 2087 ConditionListType property, used for assigning DNF / 2088 CNF semantics to subordinate policy conditions. 2089 DERIVED FROM PolicyCondition 2090 ABSTRACT FALSE 2091 PROPERTIES ConditionListType 2093 The ConditionListType property is used to specify whether the list of 2094 policy conditions associated with this compound policy condition is in 2095 disjunctive normal form (DNF) or conjunctive normal form (CNF). If this 2096 property is not present, the list type defaults to DNF. The property 2097 definition is as follows: 2099 NAME ConditionListType 2100 DESCRIPTION Indicates whether the list of policy conditions 2101 associated with this policy rule is in disjunctive 2102 normal form (DNF) or conjunctive normal form (CNF). 2103 SYNTAX uint16 2104 VALUES DNF(1), CNF(2) 2105 DEFAULT VALUE DNF(1) 2107 5.6. The Class "CompoundFilterCondition" 2109 This subclass of CompoundPolicyCondition introduces one additional 2110 property, the boolean IsMirrored. This property turns on or off the 2111 "flipping" of corresponding source and destination fields in a filter 2112 specification. 2114 NAME CompoundFilterCondition 2115 DESCRIPTION A subclass of CompoundPolicyCondition that introduces 2116 the IsMirrored property. 2117 DERIVED FROM CompoundPolicyCondition 2118 ABSTRACT FALSE 2119 PROPERTIES IsMirrored 2121 The IsMirrored property indicates whether packets that "mirror" a 2122 compound filter condition should be treated as matching the filter. The 2123 property definition is as follows: 2125 NAME IsMirrored 2126 DESCRIPTION Indicates whether packets that mirror the specified 2127 filter are to be treated as matching the filter. 2128 SYNTAX boolean 2129 DEFAULT VALUE FALSE 2131 5.7. The Class "SimplePolicyAction" 2133 The SimplePolicyAction class models the elementary set operation. "SET 2134 TO ". The set operator MUST overwrite an old value of 2135 the variable. 2137 Two aggregations are used in order to create the pair . 2138 The aggregation PolicyVariableInSimplePolicyAction relates a 2139 SimplePolicyAction to a single variable instance. Similarly, the 2140 aggregation PolicyValueInSimplePolicyAction relates a SimplePolicyAction 2141 to a single value instance. Both aggregations are defined in this 2142 document. 2144 NAME SimplePolicyAction 2145 DESCRIPTION A subclass of PolicyAction that introduces the notion 2146 of "SET variable TO value". 2147 DERIVED FROM PolicyAction 2148 ABSTRACT FALSE 2149 PROPERTIES (none) 2151 5.8. The Class "CompoundPolicyAction" 2153 The CompoundPolicyAction class is used to represent an expression 2154 consisting of an ordered sequence of action terms. Each action term is 2155 represented as a subclass of the PolicyAction class, defined in [PCIM]. 2156 Compound actions are constructed by associating dependent action terms 2157 together using the PolicyActionInPolicyAction aggregation. 2159 The class definition is as follows: 2161 NAME CompoundPolicyAction 2162 DESCRIPTION A class for representing sequenced action terms. Each 2163 action term is defined to be a subclass of the 2164 PolicyAction class. 2165 DERIVED FROM PolicyAction 2166 ABSTRACT FALSE 2167 PROPERTIES SequencedActions 2168 ExecutionStrategy 2170 This is a concrete class, and is therefore directly instantiable. 2172 The Property SequencedActions is identical to the SequencedActions 2173 property defined in PCIM for the class PolicyRule. 2175 The property ExecutionStrategy defines the execution strategy to be used 2176 upon the sequenced actions associated with this compound action. (An 2177 equivalent ExecutionStrategy property is also defined for the PolicyRule 2178 class, to provide the same indication for the sequenced actions 2179 associated with a PolicyRule.) This draft defines three execution 2180 strategies: 2182 Do Until Success � execute actions according to predefined order, until 2183 successful execution of a single sub-action. 2184 Do All - execute ALL actions which are part of the modeled 2185 set, according to their predefined order. Continue 2186 doing this, even if one or more of the sub-actions 2187 fails. 2189 Do Until Failure - execute actions according to predefined order, until 2190 the first failure in execution of a single sub- 2191 action. 2193 Since a CompoundPolicyAction may itself be aggregated either by a 2194 PolicyRule or by another CompoundPolicyAction, its success or failure 2195 will be an input to the aggregating entity's execution strategy. 2196 Consequently, the following rules are specified, for determining whether 2197 a CompoundPolicyAction succeeds or fails: 2199 If the CompoundPolicyAction's ExecutionStrategy is Do Until Success, 2200 then 2201 o If one component action succeeds, then the CompoundPolicyAction 2202 succeeds. 2203 o If all component actions fail, then the CompoundPolicyAction 2204 fails. 2206 If the CompoundPolicyAction's ExecutionStrategy is Do All, then 2207 o If all component actions succeed, then the CompoundPolicyAction 2208 succeeds. 2209 o If at least one component action fails, then the 2210 CompoundPolicyAction fails. 2212 If the CompoundPolicyAction's ExecutionStrategy is Do Until Failure, 2213 then 2214 o If all component actions succeed, then the CompoundPolicyAction 2215 succeeds. 2216 o If at least one component action fails, then the 2217 CompoundPolicyAction fails. 2219 The definition of the ExecutionStrategy property is as follows: 2221 NAME ExecutionStrategy 2222 DESCRIPTION An enumeration indicating how to interpret the action 2223 ordering for the actions aggregated by this 2224 CompoundPolicyAction. 2225 SYNTAX uint16 (ENUM, {1=Do Until Success, 2=Do All, 3=Do 2226 Until Failure} ) 2227 DEFAULT VALUE Do All (2) 2229 5.9. The Abstract Class "PolicyVariable" 2231 Variables are used for building individual conditions. The variable 2232 specifies the property of a flow or an event that should be matched when 2233 evaluating the condition. However, not every combination of a variable 2234 and a value creates a meaningful condition. For example, a source IP 2235 address variable can not be matched against a value that specifies a port 2236 number. A given variable selects the set of matchable value types. 2238 A variable can have constraints that limit the set of values within a 2239 particular value type that can be matched against it in a condition. For 2240 example, a source-port variable limits the set of values to represent 2241 integers to the range of 0-65535. Integers outside this range cannot be 2242 matched to the source-port variable, even though they are of the correct 2243 data type. Constraints for a given variable are indicated through the 2244 ExpectedPolicyValuesForVariable association. 2246 The PolicyVariable is an abstract class. Implicit and explicit context 2247 variable classes are defined as sub classes of the PolicyVariable class. 2248 A set of implicit variables is defined in this document as well. 2250 The class definition is as follows: 2252 NAME PolicyVariable 2253 DERIVED FROM Policy 2254 ABSTRACT TRUE 2255 PROPERTIES (none) 2257 5.10. The Class "PolicyExplicitVariable" 2259 Explicitly defined policy variables are evaluated within the context of 2260 the CIM Schema and its modeling constructs. The PolicyExplicitVariable 2261 class indicates the exact model property to be evaluated or manipulated. 2262 See Section 4.8.6 for a complete discussion of what happens when the 2263 values of the ModelClass and ModelProperty properties in an instance of 2264 this class do not correspond to the characteristics of the model 2265 construct being evaluated or updated. 2267 The class definition is as follows: 2269 NAME PolicyExplicitVariable 2270 DERIVED FROM PolicyVariable 2271 ABSTRACT False 2272 PROPERTIES ModelClass, ModelProperty 2274 5.10.1. The Single-Valued Property "ModelClass" 2276 This property is a string specifying the class name whose property is 2277 evaluated or set as a PolicyVariable. 2279 The property is defined as follows: 2281 NAME ModelClass 2282 SYNTAX String 2284 5.10.2. The Single-Valued Property ModelProperty 2286 This property is a string specifying the property name, within the 2287 ModelClass, which is evaluated or set as a PolicyVariable. The property 2288 is defined as follows: 2290 NAME ModelProperty 2291 SYNTAX String 2293 5.11. The Abstract Class "PolicyImplicitVariable" 2295 Implicitly defined policy variables are evaluated outside of the context 2296 of the CIM Schema and its modeling constructs. Subclasses specify the 2297 data type and semantics of the PolicyVariables. 2299 Interpretation and evaluation of a PolicyImplicitVariable can vary, 2300 depending on the particular context in which it is used. For example, a 2301 "SourceIP" address may denote the source address field of an IP packet 2302 header, or the sender address delivered by an RSVP PATH message. 2304 The class definition is as follows: 2306 NAME PolicyImplicitVariable 2307 DERIVED FROM PolicyVariable 2308 ABSTRACT True 2309 PROPERTIES ValueTypes[ ] 2311 5.11.1. The Multi-Valued Property "ValueTypes" 2313 This property is a set of strings specifying an unordered list of 2314 possible value/data types that can be used in simple conditions and 2315 actions, with this variable. The value types are specified by their 2316 class names (subclasses of PolicyValue such as PolicyStringValue). The 2317 list of class names enables an application to search on a specific name, 2318 as well as to ensure that the data type of the variable is of the correct 2319 type. 2321 The list of default ValueTypes for each subclass of 2322 PolicyImplicitVariable is specified within that variable's definition. 2324 The property is defined as follows: 2326 NAME ValueTypes 2327 SYNTAX String 2329 5.12. Subclasses of "PolicyImplicitVariable" Specified in PCIMe 2331 The following subclasses of PolicyImplicitVariable are defined in PCIMe. 2333 5.12.1. The Class "PolicySourceIPv4Variable" 2335 NAME PolicySourceIPv4Variable 2336 DESCRIPTION The source IPv4 address. of the outermost IP packet 2337 header. "Outermost" here refers to the IP packet as 2338 it flows on the wire, before any headers have been 2339 stripped from it. 2341 ALLOWED VALUE TYPES: 2342 - PolicyIPv4AddrValue 2343 DERIVED FROM PolicyImplicitVariable 2344 ABSTRACT FALSE 2345 PROPERTIES (none) 2347 5.12.2. The Class "PolicySourceIPv6Variable" 2349 NAME PolicySourceIPv6Variable 2350 DESCRIPTION The source IPv6 address of the outermost IP packet 2351 header. "Outermost" here refers to the IP packet as 2352 it flows on the wire, before any headers have been 2353 stripped from it. 2355 ALLOWED VALUE TYPES: 2356 - PolicyIPv6AddrValue 2358 DERIVED FROM PolicyImplicitVariable 2359 ABSTRACT FALSE 2360 PROPERTIES (none) 2362 5.12.3. The Class "PolicyDestinationIPv4Variable" 2364 NAME PolicyDestinationIPv4Variable 2365 DESCRIPTION The destination IPv4 address of the outermost IP 2366 packet header. "Outermost" here refers to the IP 2367 packet as it flows on the wire, before any headers 2368 have been stripped from it. 2370 ALLOWED VALUE TYPES: 2371 - PolicyIPv4AddrValue 2373 DERIVED FROM PolicyImplicitVariable 2374 ABSTRACT FALSE 2375 PROPERTIES (none) 2377 5.12.4. The Class "PolicyDestinationIPv6Variable" 2379 NAME PolicyDestinationIPv6Variable 2380 DESCRIPTION The destination IPv6 address of the outermost IP 2381 packet header. "Outermost" here refers to the IP 2382 packet as it flows on the wire, before any headers 2383 have been stripped from it. 2385 ALLOWED VALUE TYPES: 2386 - PolicyIPv6AddrValue 2388 DERIVED FROM PolicyImplicitVariable 2389 ABSTRACT FALSE 2390 PROPERTIES (none) 2391 5.12.5. The Class "PolicySourcePortVariable" 2393 NAME PolicySourcePortVariable 2394 DESCRIPTION Ports are defined as the abstraction that transport 2395 protocols use to distinguish among multiple 2396 destinations within a given host computer. For TCP 2397 and UDP flows, the PolicySourcePortVariable is 2398 logically bound to the source port field of the 2399 outermost UDP or TCP packet header. "Outermost" here 2400 refers to the IP packet as it flows on the wire, 2401 before any headers have been stripped from it. 2403 ALLOWED VALUE TYPES: 2404 - PolicyIntegerValue (0..65535) 2406 DERIVED FROM PolicyImplicitVariable 2407 ABSTRACT FALSE 2408 PROPERTIES (none) 2410 5.12.6. The Class "PolicyDestinationPortVariable" 2412 NAME PolicyDestinationPortVariable 2413 DESCRIPTION Ports are defined as the abstraction that transport 2414 protocols use to distinguish among multiple 2415 destinations within a given host computer. For TCP 2416 and UDP flows, the PolicyDestinationPortVariable is 2417 logically bound to the destination port field of the 2418 outermost UDP or TCP packet header. "Outermost" here 2419 refers to the IP packet as it flows on the wire, 2420 before any headers have been stripped from it. 2422 ALLOWED VALUE TYPES: 2423 - PolicyIntegerValue (0..65535) 2425 DERIVED FROM PolicyImplicitVariable 2426 ABSTRACT FALSE 2427 PROPERTIES (none) 2429 5.12.7. The Class "PolicyIPProtocolVariable" 2431 NAME PolicyIPProtocolVariable 2432 DESCRIPTION The IP protocol number. 2434 ALLOWED VALUE TYPES: 2435 - PolicyIntegerValue 2437 DERIVED FROM PolicyImplicitVariable 2438 ABSTRACT FALSE 2439 PROPERTIES (none) 2440 5.12.8. The Class "PolicyIPVersionVariable" 2442 NAME PolicyIPVersionVariable 2443 DESCRIPTION The IP version number. The well-known values are 4 2444 and 6. 2446 ALLOWED VALUE TYPES: 2447 - PolicyIntegerValue 2449 DERIVED FROM PolicyImplicitVariable 2450 ABSTRACT FALSE 2451 PROPERTIES (none) 2453 5.12.9. The Class "PolicyIPToSVariable" 2455 NAME PolicyIPToSVariable 2456 DESCRIPTION The IP TOS octet. 2458 ALLOWED VALUE TYPES: 2459 - PolicyIntegerValue (0..7) 2460 - PolicyBitStringValue 2462 DERIVED FROM PolicyImplicitVariable 2463 ABSTRACT FALSE 2464 PROPERTIES (none) 2466 5.12.10. The Class "PolicyDSCPVariable" 2468 NAME PolicyDSCPVariable 2469 DESCRIPTION The 6 bit Differentiated Service Code Point. 2471 ALLOWED VALUE TYPES: 2472 - PolicyIntegerValue (0..63) 2473 - PolicyBitStringValue 2475 DERIVED FROM PolicyImplicitVariable 2476 ABSTRACT FALSE 2477 PROPERTIES (none) 2479 5.12.11. The Class "PolicyFlowIdVariable" 2481 NAME PolicyFlowIdVariable 2482 DESCRIPTION The flow identifer of the outermost IPv6 packet 2483 header. "Outermost" here refers to the IP packet as 2484 it flows on the wire, before any headers have been 2485 stripped from it. 2487 ALLOWED VALUE TYPES: 2488 - PolicyIntegerValue 2489 - PolicyBitStringValue 2491 DERIVED FROM PolicyImplicitVariable 2492 ABSTRACT FALSE 2493 PROPERTIES (none) 2495 5.12.12. The Class "PolicySourceMACVariable" 2497 NAME PolicySourceMACVariable 2498 DESCRIPTION The source MAC address. 2500 ALLOWED VALUE TYPES: 2501 - PolicyMACAddrValue 2503 DERIVED FROM PolicyImplicitVariable 2504 ABSTRACT FALSE 2505 PROPERTIES (none) 2507 5.12.13. The Class "PolicyDestinationMACVariable" 2509 NAME PolicyDestinationMACVariable 2510 DESCRIPTION The destination MAC address. 2512 ALLOWED VALUE TYPES: 2513 - PolicyMACAddrValue 2515 DERIVED FROM PolicyImplicitVariable 2516 ABSTRACT FALSE 2517 PROPERTIES (none) 2519 5.12.14. The Class "PolicyVLANVariable" 2521 NAME PolicyVLANVariable 2522 DESCRIPTION The virtual Bridged Local Area Network Identifier, a 2523 12-bit field as defined in the IEEE 802.1q standard. 2525 ALLOWED VALUE TYPES: 2526 - PolicyIntegerValue 2527 - PolicyBitStringValue 2529 DERIVED FROM PolicyImplicitVariable 2530 ABSTRACT FALSE 2531 PROPERTIES (none) 2533 5.12.15. The Class "PolicyCoSVariable" 2535 NAME PolicyCoSVariable 2536 DESCRIPTION Class of Service, a 3-bit field, used in the layer 2 2537 header to select the forwarding treatment. Bound to 2538 the IEEE 802.1q user-priority field. 2540 ALLOWED VALUE TYPES: 2541 - PolicyIntegerValue 2542 - PolicyBitStringValue 2543 DERIVED FROM PolicyImplicitVariable 2544 ABSTRACT FALSE 2545 PROPERTIES (none) 2547 5.12.16. The Class "PolicyEthertypeVariable" 2549 NAME PolicyEthertypeVariable 2550 DESCRIPTION The Ethertype protocol number of Ethernet frames. 2552 ALLOWED VALUE TYPES: 2553 - PolicyIntegerValue 2554 - PolicyBitStringValue 2556 DERIVED FROM PolicyImplicitVariable 2557 ABSTRACT FALSE 2558 PROPERTIES (none) 2560 5.12.17. The Class "PolicySourceSAPVariable" 2562 NAME PolicySourceSAPVariable 2563 DESCRIPTION The Source Service Access Point (SAP) number of the 2564 IEEE 802.2 LLC header. 2566 ALLOWED VALUE TYPES: 2567 - PolicyIntegerValue 2568 - PolicyBitStringValue 2570 DERIVED FROM PolicyImplicitVariable 2571 ABSTRACT FALSE 2572 PROPERTIES (none) 2574 5.12.18. The Class "PolicyDestinationSAPVariable" 2576 NAME PolicyDestinationSAPVariable 2577 DESCRIPTION The Destination Service Access Point (SAP) number of 2578 the IEEE 802.2 LLC header. 2580 ALLOWED VALUE TYPES: 2581 - PolicyIntegerValue 2582 - PolicyBitStringValue 2584 DERIVED FROM PolicyImplicitVariable 2585 ABSTRACT FALSE 2586 PROPERTIES (none) 2588 5.12.19. The Class "PolicySNAPVariable" 2590 NAME PolicySNAPVariable 2591 DESCRIPTION The protocol number over a Sub-Network Access Protocol 2592 (SNAP) SAP encapsulation. 2594 ALLOWED VALUE TYPES: 2596 - PolicyIntegerValue 2597 - PolicyBitStringValue 2599 DERIVED FROM PolicyImplicitVariable 2600 ABSTRACT FALSE 2601 PROPERTIES (none) 2603 5.12.20. The Class "PolicyFlowDirectionVariable" 2605 NAME PolicyFlowDirectionVariable 2606 DESCRIPTION The direction of a flow relative to a network element. 2607 Direction may be "IN" and/or "OUT". 2609 ALLOWED VALUE TYPES: 2610 - PolicyStringValue 2612 DERIVED FROM PolicyImplicitVariable 2613 ABSTRACT FALSE 2614 PROPERTIES (none) 2616 To match on both inbound and outbound flows, the associated 2617 PolicyStringValue object has two entries in its StringList property: "IN" 2618 and "OUT". 2620 5.13. The Abstract Class "PolicyValue" 2622 This is an abstract class that serves as the base class for all 2623 subclasses that are used to define value objects in the PCIMe. It is 2624 used for defining values and constants used in policy conditions. The 2625 class definition is as follows: 2627 NAME PolicyValue 2628 DERIVED FROM Policy 2629 ABSTRACT True 2630 PROPERTIES (none) 2632 5.14. Subclasses of "PolicyValue" Specified in PCIMe 2634 The following subsections contain the PolicyValue subclasses defined in 2635 PCIMe. Additional subclasses may be defined in models derived from 2636 PCIMe. 2638 5.14.1. The Class "PolicyIPv4AddrValue" 2640 This class is used to provide a list of IPv4Addresses, hostnames and 2641 address range values to be matched against in a policy condition. The 2642 class definition is as follows: 2644 NAME PolicyIPv4AddrValue 2645 DERIVED FROM PolicyValue 2646 ABSTRACT False 2647 PROPERTIES IPv4AddrList[ ] 2649 The IPv4AddrList property provides an unordered list of strings, each 2650 specifying a single IPv4 address, a hostname, or a range of IPv4 2651 addresses, according to the ABNF definition [8] of an IPv4 address, as 2652 specified below: 2654 IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT 2655 IPv4prefix = IPv4address "/" 1*2DIGIT 2656 IPv4range = IPv4address"-"IPv4address 2657 IPv4maskedaddress = IPv4address","IPv4address 2658 Hostname (as defined in [9]) 2660 In the above definition, each string entry is either: 2662 1. A single IPv4address in dot notation, as defined above. Example: 2663 121.1.1.2 2665 2. An IPv4prefix address range, as defined above, specified by an 2666 address and a prefix length, separated by "/". Example: 2667 2.3.128.0/15 2669 3. An IPv4range address range defined above, specified by a starting 2670 address in dot notation and an ending address in dot notation, 2671 separated by "-". The range includes all addresses between the 2672 range's starting and ending addresses, including these two 2673 addresses. Example: 1.1.22.1-1.1.22.5 2675 4. An IPv4maskedaddress address range, as defined above, specified by 2676 an address and mask. The address and mask are represented in dot 2677 notation, separated by a comma ",". The masked address appears 2678 before the comma, and the mask appears after the comma. Example: 2679 2.3.128.0,255.255.248.0. 2681 5. A single Hostname. The Hostname format follows the guidelines and 2682 restrictions specified in [9]. Example: www.bigcompany.com. 2684 Conditions matching IPv4AddrValues evaluate to true according to the 2685 generic matching rules. Additionally, a hostname is matched against 2686 another valid IPv4address representation by resolving the hostname into 2687 an IPv4 address first, and then comparing the addresses afterwards. 2688 Matching hostnames against each other is done using a string comparison 2689 of the two names. 2691 The property definition is as follows: 2693 NAME IPv4AddrList 2694 SYNTAX String 2695 FORMAT IPv4address | IPv4prefix | IPv4range | 2696 IPv4maskedaddress | hostname 2697 5.14.2. The Class "PolicyIPv6AddrValue 2699 This class is used to define a list of IPv6 addresses, hostnames, and 2700 address range values. The class definition is as follows: 2702 NAME PolicyIPv6AddrValue 2703 DERIVED FROM PolicyValue 2704 ABSTRACT False 2705 PROPERTIES IPv6AddrList[ ] 2707 The property IPv6AddrList provides an unordered list of strings, each 2708 specifying an IPv6 address, a hostname, or a range of IPv6 addresses. 2709 IPv6 address format definition uses the standard address format defined 2710 in [10]. The ABNF definition [8] as specified in [10] is: 2712 IPv6address = hexpart [ ":" IPv4address ] 2713 IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT 2714 IPv6prefix = hexpart "/" 1*2DIGIT 2715 hexpart = hexseq | hexseq "::" [ hexseq ] | "::" [ hexseq ] 2716 hexseq = hex4 *( ":" hex4) 2717 hex4 = 1*4HEXDIG 2718 IPv6range = IPv6address"-"IPv6address 2719 IPv6maskedaddress = IPv6address","IPv6address 2720 Hostname (as defines in [NAMES]) 2722 Each string entry is either: 2724 1. A single IPv6address as defined above. 2726 2. A single Hostname. Hostname format follows guidelines and 2727 restrictions specified in [9]. 2729 3. An IPv6range address range, specified by a starting address in dot 2730 notation and an ending address in dot notation, separated by "-". 2731 The range includes all addresses between the range's starting and 2732 ending addresses, including these two addresses. 2734 4. An IPv4maskedaddress address range defined above specified by an 2735 address and mask. The address and mask are represented in dot 2736 notation separated by a comma ",". 2738 5. A single IPv6prefix as defined above. 2740 Conditions matching IPv6AddrValues evaluate to true according to the 2741 generic matching rules. Additionally, a hostname is matched against 2742 another valid IPv6address representation by resolving the hostname into 2743 an IPv6 address first, and then comparing the addresses afterwards. 2744 Matching hostnames against each other is done using a string comparison 2745 of the two names. 2747 5.14.3. The Class "PolicyMACAddrValue" 2749 This class is used to define a list of MAC addresses and MAC address 2750 range values. The class definition is as follows: 2752 NAME PolicyMACAddrValue 2753 DERIVED FROM PolicyValue 2754 ABSTRACT False 2755 PROPERTIES MACAddrList[ ] 2757 The property MACAddrList provides an unordered list of strings, each 2758 specifying a MAC address or a range of MAC addresses. The 802 MAC 2759 address canonical format is used. The ABNF definition [8] is: 2761 MACaddress = 1*4HEXDIG ":" 1*4HEXDIG ":" 1*4HEXDIG 2762 MACmaskedaddress = MACaddress","MACaddress 2764 Each string entry is either: 2766 1. A single MAC address. Example: 0000:00A5:0000 2768 2. A MACmaskedaddress address range defined specified by an address 2769 and mask. The mask specifies the relevant bits in the address. 2770 Example: 0000:00A5:0000,FFFF:FFFF:0000 defines a range of MAC 2771 addresses in which the first four octets are equal to 0000:00A5. 2773 The property definition is as follows: 2775 NAME MACAddrList 2776 SYNTAX String 2777 FORMAT MACaddress | MACmaskedaddress 2779 5.14.4. The Class "PolicyStringValue" 2781 This class is used to represent a single string value, or a set of string 2782 values. Each value can have wildcards. The class definition is as 2783 follows: 2785 NAME PolicyStringValue 2786 DERIVED FROM PolicyValue 2787 ABSTRACT False 2788 PROPERTIES StringList[ ] 2790 The property StringList provides an unordered list of strings, each 2791 representing a single string with wildcards. The asterisk character "*" 2792 is used as a wildcard, and represents an arbitrary substring replacement. 2793 For example, the value "abc*def" matches the string "abcxyzdef", and the 2794 value "abc*def*" matches the string "abcxxxdefyyyzzz". The syntax 2795 definition is identical to the substring assertion syntax defined in 2796 [11]. If the asterisk character is required as part of the string value 2797 itself, it MUST be quoted as described in section 4.3 of [11]. 2799 The property definition is as follows: 2801 NAME StringList 2802 SYNTAX String 2804 5.14.5. The Class "PolicyBitStringValue" 2806 This class is used to represent a single bit string value, or a set of 2807 bit string values. The class definition is as follows: 2809 NAME PolicyBitStringValue 2810 DERIVED FROM PolicyValue 2811 ABSTRACT False 2812 PROPERTIES BitStringList[ ] 2814 The property BitStringList provides an unordered list of strings, each 2815 representing a single bit string or a set of bit strings. The number of 2816 bits specified SHOULD equal the number of bits of the expected variable. 2817 For example, for a one-octet variable, 8 bits should be specified. If 2818 the variable does not have a fixed length, the bit string should be 2819 matched against the variable's most significant bit string. The formal 2820 definition of a bit string is: 2822 binary-digit = "0" / "1" 2823 bitString = 1*binary-digit 2824 maskedBitString = bitString","bitString 2826 Each string entry is either: 2828 1. A single bit string. Example: 00111010 2830 2. A range of bit strings specified using a bit string and a bit 2831 mask. The bit string and mask fields have the same number of bits 2832 specified. The mask bit string specifies the significant bits in 2833 the bit string value. For example, 110110, 100110 and 110111 2834 would match the maskedBitString 100110,101110 but 100100 would 2835 not. 2837 The property definition is as follows: 2839 NAME BitStringList 2840 SYNTAX String 2841 FORMAT bitString | maskedBitString 2843 5.14.6. The Class "PolicyIntegerValue" 2845 This class provides a list of integer and integer range values. Integers 2846 of arbitrary sizes can be represented. The class definition is as 2847 follows: 2849 NAME PolicyIntegerValue 2850 DERIVED FROM PolicyValue 2851 ABSTRACT False 2852 PROPERTIES IntegerList[ ] 2854 The property IntegerList provides an unordered list of integers and 2855 integer range values, represented as strings. The format of this 2856 property takes one of the following forms: 2858 1. An integer value. 2860 2. A range of integers. The range is specified by a starting integer 2861 and an ending integer, separated by '..'. The starting integer 2862 MUST be less than or equal to the ending integer. The range 2863 includes all integers between the starting and ending integers, 2864 including these two integers. 2866 To represent a range of integers that is not bounded, the reserved words 2867 -INFINITY and/or INFINITY can be used in place of the starting and ending 2868 integers. In addition to ordinary integer matches, INFINITY matches 2869 INFINITY and -INFINITY matches -INFINITY. 2871 The ABNF definition [8] is: 2873 integer = [-]1*DIGIT | "INFINITY" | "-INFINITY" 2874 integerrange = integer".."integer 2876 Using ranges, the operators greater-than, greater-than-or-equal-to, less- 2877 than, and less-than-or-equal-to can be expressed. For example, "X is- 2878 greater-than 5" (where X is an integer) can be translated to "X matches 2879 6-INFINITY". This enables the match condition semantics of the operator 2880 for the SimplePolicyCondition class to be kept simple (i.e., just the 2881 value "match"). 2883 The property definition is as follows: 2885 NAME IntegerList 2886 SYNTAX String 2887 FORMAT integer | integerrange 2889 5.14.7. The Class "PolicyBooleanValue" 2891 This class is used to represent a Boolean (TRUE/FALSE) value. The class 2892 definition is as follows: 2894 NAME PolicyBooleanValue 2895 DERIVED FROM PolicyValue 2896 ABSTRACT False 2897 PROPERTIES BooleanValue 2899 The property definition is as follows: 2901 NAME BooleanValue 2902 SYNTAX boolean 2903 5.15. The Class "PolicyRoleCollection" 2905 This class represents a collection of managed elements that share a 2906 common role. The PolicyRoleCollection always exists in the context of a 2907 system, specified using the PolicyRoleCollectionInSystem association. 2908 The value of the PolicyRole property in this class specifies the role, 2909 and can be matched with the value(s) in the PolicyRoles array in 2910 PolicyRules and PolicyGroups. ManagedElements that share the role 2911 defined in this collection are aggregated into the collection via the 2912 association ElementInPolicyRoleCollection. 2914 NAME PolicyRoleCollection 2915 DESCRIPTION A subclass of the CIM Collection class used to group 2916 together managed elements that share a role. 2917 DERIVED FROM Collection 2918 ABSTRACT FALSE 2919 PROPERTIES PolicyRole 2921 5.15.1. The Single-Valued Property "PolicyRole" 2923 This property represents the role associated with a PolicyRoleCollection. 2924 The property definition is as follows: 2926 NAME PolicyRole 2927 DESCRIPTION A string representing the role associated with a 2928 PolicyRoleCollection. 2929 SYNTAX string 2931 5.16. The Class "ReusablePolicyContainer" 2933 The new class ReusablePolicyContainer is defined as follows: 2935 NAME ReusablePolicyContainer 2936 DESCRIPTION A class representing an administratively defined 2937 container for reusable policy-related information. 2938 This class does not introduce any additional 2939 properties beyond those in its superclass AdminDomain. 2940 It does, however, participate in a number of unique 2941 associations. 2942 DERIVED FROM AdminDomain 2943 ABSTRACT FALSE 2944 PROPERTIES (none) 2946 5.17. Deprecate PCIM's Class "PolicyRepository" 2948 The class definition of PolicyRepository (from PCIM) is updated as 2949 follows, with an indication that the class has been deprecated. Note 2950 that when an element of the model is deprecated, its replacement element 2951 is identified explicitly. 2953 NAME PolicyRepository 2954 DEPRECATED FOR ReusablePolicyContainer 2955 DESCRIPTION A class representing an administratively defined 2956 container for reusable policy-related information. 2957 This class does not introduce any additional 2958 properties beyond those in its superclass AdminDomain. 2959 It does, however, participate in a number of unique 2960 associations. 2961 DERIVED FROM AdminDomain 2962 ABSTRACT FALSE 2963 PROPERTIES (none) 2965 5.18. The Abstract Class "FilterEntryBase" 2967 FilterEntryBase is the abstract base class from which all filter entry 2968 classes are derived. It serves as the endpoint for the 2969 EntriesInFilterList aggregation, which groups filter entries into filter 2970 lists. Its properties include CIM naming attributes and an IsNegated 2971 boolean property (to easily "NOT" the match information specified in an 2972 instance of one of its subclasses). 2974 The class definition is as follows: 2976 NAME FilterEntryBase 2977 DESCRIPTION An abstract class representing a single 2978 filter that is aggregated into a 2979 FilterList via the aggregation 2980 EntriesInFilterList. 2981 DERIVED FROM LogicalElement 2982 TYPE Abstract 2983 PROPERTIES IsNegated 2985 5.19. The Class "IpHeadersFilter" 2987 This concrete class contains the most commonly required properties for 2988 performing filtering on IP, TCP or UDP headers. Properties not present 2989 in an instance of IPHeadersFilter are treated as 'all values'. A 2990 property HdrIpVersion identifies whether the IP addresses in an instance 2991 are IPv4 or IPv6 addresses. Since the source and destination IP 2992 addresses come from the same packet header, they will always be of the 2993 same type. 2995 The class definition is as follows: 2997 NAME IpHeadersFilter 2998 DESCRIPTION A class representing an entire IP 2999 header filter, or any subset of one. 3000 DERIVED FROM FilterEntryBase 3001 TYPE Concrete 3002 PROPERTIES HdrIpVersion, HdrSrcAddress, HdrSrcMask, 3003 HdrDestAddress, HdrDestMask, HdrProtocolID, 3004 HdrSrcPortStart, HdrSrcPortEnd, 3005 HdrDestPortStart, HdrDestPortEnd, HdrDSCP, 3006 HdrFlowLabel 3008 5.19.1. The Property HdrIpVersion 3010 This property is an 8-bit unsigned integer, identifying the version of 3011 the IP addresses to be filtered on. IP versions are identified as they 3012 are in the Version field of the IP packet header - IPv4 = 4, IPv6 = 6. 3013 These two values are the only ones defined for this property. 3015 The value of this property determines the sizes of the OctetStrings in 3016 the four properties HdrSrcAddress, HdrSrcMask, HdrDestAddress, and 3017 HdrDestMask, as follows: 3019 o IPv4: OctetString(SIZE (4)) 3020 o IPv6: OctetString(SIZE (16|20)), depending on whether a scope 3021 identifier is present 3023 If a value for this property is not provided, then the filter does not 3024 consider IP version in selecting matching packets, i.e., IP version 3025 matches for all values. In this case, the HdrSrcAddress, HdrSrcMask, 3026 HdrDestAddress, and HdrDestMask must also not be present. 3028 5.19.2. The Property HdrSrcAddress 3030 This property is an OctetString, of a size determined by the value of the 3031 HdrIpVersion property, representing a source IP address. This value is 3032 compared to the source address in the IP header, subject to the mask 3033 represented in the HdrSrcMask property. 3035 If a value for this property is not provided, then the filter does not 3036 consider HdrSrcAddress in selecting matching packets, i.e., HdrSrcAddress 3037 matches for all values. 3039 5.19.3. The Property HdrSrcMask 3041 This property is an OctetString, of a size determined by the value of the 3042 HdrIpVersion property, representing a mask to be used in comparing the 3043 source address in the IP header with the value represented in the 3044 HdrSrcAddress property. 3046 If a value for this property is not provided, then the filter does not 3047 consider HdrSrcMask in selecting matching packets, i.e., the value of 3048 HdrSrcAddress must match the source address in the packet exactly. 3050 5.19.4. The Property HdrDestAddress 3052 This property is an OctetString, of a size determined by the value of the 3053 HdrIpVersion property, representing a destination IP address. This value 3054 is compared to the destination address in the IP header, subject to the 3055 mask represented in the HdrDestMask property. 3057 If a value for this property is not provided, then the filter does not 3058 consider HdrDestAddress in selecting matching packets, i.e., 3059 HdrDestAddress matches for all values. 3061 5.19.5. The Property HdrDestMask 3063 This property is an OctetString, of a size determined by the value of the 3064 HdrIpVersion property, representing a mask to be used in comparing the 3065 destination address in the IP header with the value represented in the 3066 HdrDestAddress property. 3068 If a value for this property is not provided, then the filter does not 3069 consider HdrDestMask in selecting matching packets, i.e., the value of 3070 HdrDestAddress must match the destination address in the packet exactly. 3072 5.19.6. The Property HdrProtocolID 3074 This property is an 8-bit unsigned integer, representing an IP protocol 3075 type. This value is compared to the Protocol field in the IP header. 3077 If a value for this property is not provided, then the filter does not 3078 consider HdrProtocolID in selecting matching packets, i.e., HdrProtocolID 3079 matches for all values. 3081 5.19.7. The Property HdrSrcPortStart 3083 This property is a 16-bit unsigned integer, representing the lower end of 3084 a range of UDP or TCP source ports. The upper end of the range is 3085 represented by the HdrSrcPortEnd property. The value of HdrSrcPortStart 3086 MUST be no greater than the value of HdrSrcPortEnd. A single port is 3087 indicated by equal values for HdrSrcPortStart and HdrSrcPortEnd. 3089 A source port filter is evaluated by testing whether the source port 3090 identified in the IP header falls within the range of values between 3091 HdrSrcPortStart and HdrSrcPortEnd, including these two end points. 3093 If a value for this property is not provided, then the filter does not 3094 consider HdrSrcPortStart in selecting matching packets, i.e., there is no 3095 lower bound in matching source port values. 3097 5.19.8. The Property HdrSrcPortEnd 3099 This property is a 16-bit unsigned integer, representing the upper end of 3100 a range of UDP or TCP source ports. The lower end of the range is 3101 represented by the HdrSrcPortStart property. The value of HdrSrcPortEnd 3102 MUST be no less than the value of HdrSrcPortStart. A single port is 3103 indicated by equal values for HdrSrcPortStart and HdrSrcPortEnd. 3105 A source port filter is evaluated by testing whether the source port 3106 identified in the IP header falls within the range of values between 3107 HdrSrcPortStart and HdrSrcPortEnd, including these two end points. 3109 If a value for this property is not provided, then the filter does not 3110 consider HdrSrcPortEnd in selecting matching packets, i.e., there is no 3111 upper bound in matching source port values. 3113 5.19.9. The Property HdrDestPortStart 3115 This property is a 16-bit unsigned integer, representing the lower end of 3116 a range of UDP or TCP destination ports. The upper end of the range is 3117 represented by the HdrDestPortEnd property. The value of 3118 HdrDestPortStart MUST be no greater than the value of HdrDestPortEnd. A 3119 single port is indicated by equal values for HdrDestPortStart and 3120 HdrDestPortEnd. 3122 A destination port filter is evaluated by testing whether the destination 3123 port identified in the IP header falls within the range of values between 3124 HdrDestPortStart and HdrDestPortEnd, including these two end points. 3126 If a value for this property is not provided, then the filter does not 3127 consider HdrDestPortStart in selecting matching packets, i.e., there is 3128 no lower bound in matching destination port values. 3130 5.19.10. The Property HdrDestPortEnd 3132 This property is a 16-bit unsigned integer, representing the upper end of 3133 a range of UDP or TCP destination ports. The lower end of the range is 3134 represented by the HdrDestPortStart property. The value of 3135 HdrDestPortEnd MUST be no less than the value of HdrDestPortStart. A 3136 single port is indicated by equal values for HdrDestPortStart and 3137 HdrDestPortEnd. 3139 A destination port filter is evaluated by testing whether the destination 3140 port identified in the IP header falls within the range of values between 3141 HdrDestPortStart and HdrDestPortEnd, including these two end points. 3143 If a value for this property is not provided, then the filter does not 3144 consider HdrDestPortEnd in selecting matching packets, i.e., there is no 3145 upper bound in matching destination port values. 3147 5.19.11. The Property HdrDSCP 3149 The property HdrDSCP is defined as a uint8, restricted to the range 3150 0..63. Since DSCPs are defined as discrete code points, with no inherent 3151 structure, there is no semantically significant relationship between 3152 different DSCPs. Consequently, there is no provision for specifying a 3153 range of DSCPs in this property. 3155 If a value for this property is not provided, then the filter does not 3156 consider HdrDSCP in selecting matching packets, i.e., HdrDSCP matches for 3157 all values. 3159 5.19.12. The Property HdrFlowLabel 3161 The 20-bit Flow Label field in the IPv6 header may be used by a source to 3162 label sequences of packets for which it requests special handling by IPv6 3163 devices, such as non-default quality of service or 'real-time' service. 3164 This property is an octet string of size 3 (that is, 24 bits), in which 3165 the 20-bit Flow Label appears in the rightmost 20 bits, padded on the 3166 left with b'0000'. 3168 If a value for this property is not provided, then the filter does not 3169 consider HdrFlowLabel in selecting matching packets, i.e., HdrFlowLabel 3170 matches for all values. 3172 5.20. The Class "8021Filter" 3174 This concrete class allows 802.1.source and destination MAC addresses, as 3175 well as the 802.1 protocol ID, priority, and VLAN identifier fields, to 3176 be expressed in a single object 3178 The class definition is as follows: 3180 NAME 8021Filter 3181 DESCRIPTION A class that allows 802.1 source 3182 and destination MAC address and 3183 protocol ID, priority, and VLAN 3184 identifier filters to be 3185 expressed in a single object. 3186 DERIVED FROM FilterEntryBase 3187 TYPE Concrete 3188 PROPERTIES 8021HdrSrcMACAddr, 8021HdrSrcMACMask, 3189 8021HdrDestMACAddr, 8021HdrDestMACMask, 3190 8021HdrProtocolID, 8021HdrPriorityValue, 3191 8021HDRVLANID 3193 5.20.1. The Property 8021HdrSrcMACAddr 3195 This property is an OctetString of size 6, representing a 48-bit source 3196 MAC address in canonical format. This value is compared to the 3197 SourceAddress field in the MAC header, subject to the mask represented in 3198 the 8021HdrSrcMACMask property. 3200 If a value for this property is not provided, then the filter does not 3201 consider 8021HdrSrcMACAddr in selecting matching packets, i.e., 3202 8021HdrSrcMACAddr matches for all values. 3204 5.20.2. The Property 8021HdrSrcMACMask 3206 This property is an OctetString of size 6, representing a 48-bit mask to 3207 be used in comparing the SourceAddress field in the MAC header with the 3208 value represented in the 8021HdrSrcMACAddr property. 3210 If a value for this property is not provided, then the filter does not 3211 consider 8021HdrSrcMACMask in selecting matching packets, i.e., the value 3212 of 8021HdrSrcMACAddr must match the source MAC address in the packet 3213 exactly. 3215 5.20.3. The Property 8021HdrDestMACAddr 3217 This property is an OctetString of size 6, representing a 48-bit 3218 destination MAC address in canonical format. This value is compared to 3219 the DestinationAddress field in the MAC header, subject to the mask 3220 represented in the 8021HdrDestMACMask property. 3222 If a value for this property is not provided, then the filter does not 3223 consider 8021HdrDestMACAddr in selecting matching packets, i.e., 3224 8021HdrDestMACAddr matches for all values. 3226 5.20.4. The Property 8021HdrDestMACMask 3228 This property is an OctetString of size 6, representing a 48-bit mask to 3229 be used in comparing the DestinationAddress field in the MAC header with 3230 the value represented in the 8021HdrDestMACAddr property. 3232 If a value for this property is not provided, then the filter does not 3233 consider 8021HdrDestMACMask in selecting matching packets, i.e., the 3234 value of 8021HdrDestMACAddr must match the destination MAC address in the 3235 packet exactly. 3237 5.20.5. The Property 8021HdrProtocolID 3239 This property is a 16-bit unsigned integer, representing an Ethernet 3240 protocol type. This value is compared to the Ethernet Type field in the 3241 802.3 MAC header. 3243 If a value for this property is not provided, then the filter does not 3244 consider 8021HdrProtocolID in selecting matching packets, i.e., 3245 8021HdrProtocolID matches for all values. 3247 5.20.6. The Property 8021HdrPriorityValue 3249 This property is an 8-bit unsigned integer, representing an 802.1Q 3250 priority. This value is compared to the Priority field in the 802.1Q 3251 header. Since the 802.1Q Priority field consists of 3 bits, the values 3252 for this property are limited to the range 0..7. 3254 If a value for this property is not provided, then the filter does not 3255 consider 8021HdrPriorityValue in selecting matching packets, i.e., 3256 8021HdrPriorityValue matches for all values. 3258 5.20.7. The Property 8021HdrVLANID 3260 This property is a 32-bit unsigned integer, representing an 802.1Q VLAN 3261 Identifier. This value is compared to the VLAN ID field in the 802.1Q 3262 header. Since the 802.1Q VLAN ID field consists of 12 bits, the values 3263 for this property are limited to the range 0..4095. 3265 If a value for this property is not provided, then the filter does not 3266 consider 8021HdrVLANID in selecting matching packets, i.e., 8021HdrVLANID 3267 matches for all values. 3269 5.21. The Class FilterList 3271 This is a concrete class that aggregates instances of (subclasses of) 3272 FilterEntryBase via the aggregation EntriesInFilterList. It is possible 3273 to aggregate different types of filters into a single FilterList - for 3274 example, packet header filters (represented by the IpHeadersFilter class) 3275 and security filters (represented by subclasses of FilterEntryBase 3276 defined by IPsec). 3278 The aggregation property EntriesInFilterList.EntrySequence serves to 3279 order the filter entries in a FilterList. This is necessary when 3280 algorithms such as "Match First" are used to identify traffic based on an 3281 aggregated set of FilterEntries. In modeling QoS classifiers, however, 3282 this property is always set to 0, to indicate that the aggregated filter 3283 entries are ANDed together to form a selector for a class of traffic. 3285 The class definition is as follows: 3287 NAME FilterList 3288 DESCRIPTION A concrete class representing 3289 the aggregation of multiple filters. 3290 DERIVED FROM LogicalElement 3291 TYPE Concrete 3292 PROPERTIES Direction 3294 5.21.1. The Property Direction 3296 This property is a 16-bit unsigned integer enumeration, representing the 3297 direction of the traffic flow to which the FilterList is to be applied. 3298 Defined enumeration values are 3300 o NotApplicable(0) 3301 o Input(1) 3302 o Output(2) 3303 o Both(3) - This value is used to indicate that the direction is 3304 immaterial, e.g., to filter on a source subnet regardless of 3305 whether the flow is inbound or outbound 3306 o Mirrored(4) - This value is also applicable to both inbound and 3307 outbound flow processing, but it indicates that the filter criteria 3308 are applied asymmetrically to traffic in both directions and, thus, 3309 specifies the reversal of source and destination criteria (as 3310 opposed to the equality of these criteria as indicated by "Both"). 3311 The match conditions in the aggregated FilterEntryBase subclass 3312 instances are defined from the perspective of outbound flows and 3313 applied to inbound flows as well by reversing the source and 3314 destination criteria. So, for example, consider a FilterList with 3315 3 filter entries indicating destination port = 80, and source and 3316 destination addresses of a and b, respectively. Then, for the 3317 outbound direction, the filter entries match as specified and the 3318 'mirror' (for the inbound direction) matches on source port = 80 3319 and source and destination addresses of b and a, respectively. 3321 6. Association and Aggregation Definitions 3323 The following definitions supplement those in PCIM itself. PCIM 3324 definitions that are not DEPRECATED here are still current parts of the 3325 overall Policy Core Information Model. 3327 6.1. The Aggregation "PolicySetComponent" 3329 PolicySetComponent is a new aggregation class that collects instances of 3330 PolicySet subclasses (PolicyGroups and PolicyRules) into coherent sets of 3331 policies. 3333 NAME PolicySetComponent 3334 DESCRIPTION A concrete class representing the components of a 3335 policy set that have the same decision strategy, and 3336 are prioritized within the set. 3337 DERIVED FROM PolicyComponent 3338 ABSTRACT FALSE 3339 PROPERTIES GroupComponent[ref PolicySet[0..n]] 3340 PartComponent[ref PolicySet[0..n]] 3341 Priority 3343 The definition of the Priority property is unchanged from its previous 3344 definition in [PCIM]. 3346 NAME Priority 3347 DESCRIPTION A non-negative integer for prioritizing this PolicySet 3348 component relative to other components of the same 3349 PolicySet. A larger value indicates a higher 3350 priority. 3351 SYNTAX uint16 3352 DEFAULT VALUE 0 3354 6.2. Deprecate PCIM's Aggregation "PolicyGroupInPolicyGroup" 3356 The new aggregation PolicySetComponent is used directly to represent 3357 aggregation of PolicyGroups by a higher-level PolicyGroup. Thus the 3358 aggregation PolicyGroupInPolicyGroup is no longer needed, and can be 3359 deprecated. 3361 NAME PolicyGroupInPolicyGroup 3362 DEPRECATED FOR PolicySetComponent 3363 DESCRIPTION A class representing the aggregation of PolicyGroups 3364 by a higher-level PolicyGroup. 3366 DERIVED FROM PolicyComponent 3367 ABSTRACT FALSE 3368 PROPERTIES GroupComponent[ref PolicyGroup[0..n]] 3369 PartComponent[ref PolicyGroup[0..n]] 3371 6.3. Deprecate PCIM's Aggregation "PolicyRuleInPolicyGroup" 3373 The new aggregation PolicySetComponent is used directly to represent 3374 aggregation of PolicyRules by a PolicyGroup. Thus the aggregation 3375 PolicyRuleInPolicyGroup is no longer needed, and can be deprecated. 3377 NAME PolicyRuleInPolicyGroup 3378 DEPRECATED FOR PolicySetComponent 3379 DESCRIPTION A class representing the aggregation of PolicyRules by 3380 a PolicyGroup. 3381 DERIVED FROM PolicyComponent 3382 ABSTRACT FALSE 3383 PROPERTIES GroupComponent[ref PolicyGroup[0..n]] 3384 PartComponent[ref PolicyRule[0..n]] 3386 6.4. The Abstract Association "PolicySetInSystem" 3388 PolicySetInSystem is a new association that defines a relationship 3389 between a System and a PolicySet used in the administrative scope of that 3390 system (e.g., AdminDomain, ComputerSystem). The Priority property is 3391 used to assign a relative priority to a PolicySet within the 3392 administrative scope in contexts where it is not a component of another 3393 PolicySet. 3395 NAME PolicySetInSystem 3396 DESCRIPTION An abstract class representing the relationship 3397 between a System and a PolicySet that is used in the 3398 administrative scope of the System. 3399 DERIVED FROM PolicyInSystem 3400 ABSTRACT TRUE 3401 PROPERTIES Antecedent[ref System[0..1]] 3402 Dependent [ref PolicySet[0..n]] 3403 Priority 3405 The Priority property is used to specify the relative priority of the 3406 referenced PolicySet when there are more than one PolicySet instances 3407 applied to a managed resource that are not PolicySetComponents and, 3408 therefore, have no other relative priority defined. 3410 NAME Priority 3411 DESCRIPTION A non-negative integer for prioritizing the referenced 3412 PolicySet among other PolicySet instances that are not 3413 components of a common PolicySet. A larger value 3414 indicates a higher priority. 3416 SYNTAX uint16 3417 DEFAULT VALUE 0 3419 6.5. Update PCIM's Weak Association "PolicyGroupInSystem" 3421 Regardless of whether it a component of another PolicySet, a PolicyGroup 3422 is itself defined within the scope of a System. This association links a 3423 PolicyGroup to the System in whose scope the PolicyGroup is defined. It 3424 is a subclass of the abstract PolicySetInSystem association. The class 3425 definition for the association is as follows: 3427 NAME PolicyGroupInSystem 3428 DESCRIPTION A class representing the fact that a PolicyGroup is 3429 defined within the scope of a System. 3430 DERIVED FROM PolicySetInSystem 3431 ABSTRACT FALSE 3432 PROPERTIES Antecedent[ref System[1..1]] 3433 Dependent [ref PolicyGroup[weak]] 3435 The Reference "Antecedent" is inherited from PolicySetInSystem, and 3436 overridden to restrict its cardinality to [1..1]. It serves as an object 3437 reference to a System that provides a scope for one or more PolicyGroups. 3438 Since this is a weak association, the cardinality for this object 3439 reference is always 1, that is, a PolicyGroup is always defined within 3440 the scope of exactly one System. 3442 The Reference "Dependent" is inherited from PolicySetInSystem, and 3443 overridden to become an object reference to a PolicyGroup defined within 3444 the scope of a System. Note that for any single instance of the 3445 association class PolicyGroupInSystem, this property (like all reference 3446 properties) is single-valued. The [0..n] cardinality indicates that a 3447 given System may have 0, 1, or more than one PolicyGroups defined within 3448 its scope. 3450 6.6. Update PCIM's Weak Association "PolicyRuleInSystem" 3452 Regardless of whether it a component of another PolicySet, a PolicyRule 3453 is itself defined within the scope of a System. This association links a 3454 PolicyRule to the System in whose scope the PolicyRule is defined. It is 3455 a subclass of the abstract PolicySetInSystem association. The class 3456 definition for the association is as follows: 3458 NAME PolicyRuleInSystem 3459 DESCRIPTION A class representing the fact that a PolicyRule is 3460 defined within the scope of a System. 3461 DERIVED FROM PolicySetInSystem 3462 ABSTRACT FALSE 3463 PROPERTIES Antecedent[ref System[1..1]] 3464 Dependent[ref PolicyRule[weak]] 3466 The Reference "Antecedent" is inherited from PolicySetInSystem, and 3467 overridden to restrict its cardinality to [1..1]. It serves as an object 3468 reference to a System that provides a scope for one or more PolicyRules. 3469 Since this is a weak association, the cardinality for this object 3470 reference is always 1, that is, a PolicyRule is always defined within the 3471 scope of exactly one System. 3473 The Reference "Dependent" is inherited from PolicySetInSystem, and 3474 overridden to become an object reference to a PolicyRule defined within 3475 the scope of a System. Note that for any single instance of the 3476 association class PolicyRuleInSystem, this property (like all Reference 3477 properties) is single-valued. The [0..n] cardinality indicates that a 3478 given System may have 0, 1, or more than one PolicyRules defined within 3479 its scope. 3481 6.7. The Abstract Aggregation "PolicyConditionStructure" 3483 NAME PolicyConditionStructure 3484 DESCRIPTION A class representing the aggregation of 3485 PolicyConditions by an aggregating instance. 3486 DERIVED FROM PolicyComponent 3487 ABSTRACT TRUE 3488 PROPERTIES PartComponent[ref PolicyCondition[0..n]] 3489 GroupNumber 3490 ConditionNegated 3492 6.8. Update PCIM's Aggregation "PolicyConditionInPolicyRule" 3494 The PCIM aggregation "PolicyConditionInPolicyRule" is updated, to make it 3495 a subclass of the new abstract aggregation PolicyConditionStructure. The 3496 properties GroupNumber and ConditionNegated are now inherited, rather 3497 than specified explicitly as they were in PCIM. 3499 NAME PolicyConditionInPolicyRule 3500 DESCRIPTION A class representing the aggregation of 3501 PolicyConditions by a PolicyRule. 3502 DERIVED FROM PolicyConditionStructure 3503 ABSTRACT FALSE 3504 PROPERTIES GroupComponent[ref PolicyRule[0..n]] 3506 6.9. The Aggregation "PolicyConditionInPolicyCondition" 3508 A second subclass of PolicyConditionStructure is defined, representing 3509 the compounding of policy conditions into a higher-level policy 3510 condition. 3512 NAME PolicyConditionInPolicyCondition 3513 DESCRIPTION A class representing the aggregation of 3514 PolicyConditions by another PolicyCondition. 3515 DERIVED FROM PolicyConditionStructure 3516 ABSTRACT FALSE 3517 PROPERTIES GroupComponent[ref CompoundPolicyCondition[0..n]] 3518 6.10. The Abstract Aggregation "PolicyActionStructure" 3520 NAME PolicyActionStructure 3521 DESCRIPTION A class representing the aggregation of PolicyActions 3522 by an aggregating instance. 3523 DERIVED FROM PolicyComponent 3524 ABSTRACT TRUE 3525 PROPERTIES PartComponent[ref PolicyAction[0..n]] 3526 ActionOrder 3528 The definition of the ActionOrder property appears in Section 7.8.3 of 3529 PCIM [3]. 3531 6.11. Update PCIM's Aggregation "PolicyActionInPolicyRule" 3533 The PCIM aggregation "PolicyActionInPolicyRule" is updated, to make it a 3534 subclass of the new abstract aggregation PolicyActionStructure. The 3535 property ActionOrder is now inherited, rather than specified explicitly 3536 as it was in PCIM. 3538 NAME PolicyActionInPolicyRule 3539 DESCRIPTION A class representing the aggregation of PolicyActions 3540 by a PolicyRule. 3541 DERIVED FROM PolicyActionStructure 3542 ABSTRACT FALSE 3543 PROPERTIES GroupComponent[ref PolicyRule[0..n]] 3545 6.12. The Aggregation "PolicyActionInPolicyAction" 3547 A second subclass of PolicyActionStructure is defined, representing the 3548 compounding of policy actions into a higher-level policy action. 3550 NAME PolicyActionInPolicyAction 3551 DESCRIPTION A class representing the aggregation of PolicyActions 3552 by another PolicyAction. 3553 DERIVED FROM PolicyActionStructure 3554 ABSTRACT FALSE 3555 PROPERTIES GroupComponent[ref CompoundPolicyAction[0..n]] 3557 6.13. The Aggregation "PolicyVariableInSimplePolicyCondition" 3559 A simple policy condition is represented as an ordered triplet {variable, 3560 operator, value}. This aggregation provides the linkage between a 3561 SimplePolicyCondition instance and a single PolicyVariable. The 3562 aggregation PolicyValueInSimplePolicyCondition links the 3563 SimplePolicyCondition to a single PolicyValue. The Operator property of 3564 SimplePolicyCondition represents the third element of the triplet, the 3565 operator. 3567 The class definition for this aggregation is as follows: 3569 NAME PolicyVariableInSimplePolicyCondition 3570 DERIVED FROM PolicyComponent 3571 ABSTRACT False 3572 PROPERTIES GroupComponent[ref SimplePolicyCondition[0..n]] 3573 PartComponent[ref PolicyVariable[1..1] ] 3575 The reference property "GroupComponent" is inherited from 3576 PolicyComponent, and overridden to become an object reference to a 3577 SimplePolicyCondition that contains exactly one PolicyVariable. Note 3578 that for any single instance of the aggregation class 3579 PolicyVariableInSimplePolicyCondition, this property is single-valued. 3580 The [0..n] cardinality indicates that there may be 0, 1, or more 3581 SimplePolicyCondition objects that contain any given policy variable 3582 object. 3584 The reference property "PartComponent" is inherited from PolicyComponent, 3585 and overridden to become an object reference to a PolicyVariable that is 3586 defined within the scope of a SimplePolicyCondition. Note that for any 3587 single instance of the association class 3588 PolicyVariableInSimplePolicyCondition, this property (like all reference 3589 properties) is single-valued. The [1..1] cardinality indicates that a 3590 SimplePolicyCondition must have exactly one policy variable defined 3591 within its scope in order to be meaningful. 3593 6.14. The Aggregation "PolicyValueInSimplePolicyCondition" 3595 A simple policy condition is represented as an ordered triplet {variable, 3596 operator, value}. This aggregation provides the linkage between a 3597 SimplePolicyCondition instance and a single PolicyValue. The aggregation 3598 PolicyVariableInSimplePolicyCondition links the SimplePolicyCondition to 3599 a single PolicyVariable. The Operator property of SimplePolicyCondition 3600 represents the third element of the triplet, the operator. 3602 The class definition for this aggregation is as follows: 3604 NAME PolicyValueInSimplePolicyCondition 3605 DERIVED FROM PolicyComponent 3606 ABSTRACT False 3607 PROPERTIES GroupComponent[ref SimplePolicyCondition[0..n]] 3608 PartComponent[ref PolicyValue[1..1] ] 3610 The reference property "GroupComponent" is inherited from 3611 PolicyComponent, and overridden to become an object reference to a 3612 SimplePolicyCondition that contains exactly one PolicyValue. Note that 3613 for any single instance of the aggregation class 3614 PolicyValueInSimplePolicyCondition, this property is single-valued. The 3615 [0..n] cardinality indicates that there may be 0, 1, or more 3616 SimplePolicyCondition objects that contain any given policy value object. 3618 The reference property "PartComponent" is inherited from PolicyComponent, 3619 and overridden to become an object reference to a PolicyValue that is 3620 defined within the scope of a SimplePolicyCondition. Note that for any 3621 single instance of the association class 3622 PolicyValueInSimplePolicyCondition, this property (like all reference 3623 properties) is single-valued. The [1..1] cardinality indicates that a 3624 SimplePolicyCondition must have exactly one policy value defined within 3625 its scope in order to be meaningful. 3627 6.15. The Aggregation "PolicyVariableInSimplePolicyAction" 3629 A simple policy action is represented as a pair {variable, value}. This 3630 aggregation provides the linkage between a SimplePolicyAction instance 3631 and a single PolicyVariable. The aggregation 3632 PolicyValueInSimplePolicyAction links the SimplePolicyAction to a single 3633 PolicyValue. 3635 The class definition for this aggregation is as follows: 3637 NAME PolicyVariableInSimplePolicyAction 3638 DERIVED FROM PolicyComponent 3639 ABSTRACT False 3640 PROPERTIES GroupComponent[ref SimplePolicyAction[0..n]] 3641 PartComponent[ref PolicyVariable[1..1] ] 3643 The reference property "GroupComponent" is inherited from 3644 PolicyComponent, and overridden to become an object reference to a 3645 SimplePolicyAction that contains exactly one PolicyVariable. Note that 3646 for any single instance of the aggregation class 3647 PolicyVariableInSimplePolicyAction, this property is single-valued. The 3648 [0..n] cardinality indicates that there may be 0, 1, or more 3649 SimplePolicyAction objects that contain any given policy variable object. 3651 The reference property "PartComponent" is inherited from PolicyComponent, 3652 and overridden to become an object reference to a PolicyVariable that is 3653 defined within the scope of a SimplePolicyAction. Note that for any 3654 single instance of the association class 3655 PolicyVariableInSimplePolicyAction, this property (like all reference 3656 properties) is single-valued. The [1..1] cardinality indicates that a 3657 SimplePolicyAction must have exactly one policy variable defined within 3658 its scope in order to be meaningful. 3660 6.16. The Aggregation "PolicyValueInSimplePolicyAction" 3662 A simple policy action is represented as a pair {variable, value}. This 3663 aggregation provides the linkage between a SimplePolicyAction instance 3664 and a single PolicyValue. The aggregation 3665 PolicyVariableInSimplePolicyAction links the SimplePolicyAction to a 3666 single PolicyVariable. 3668 The class definition for this aggregation is as follows: 3670 NAME PolicyValueInSimplePolicyAction 3671 DERIVED FROM PolicyComponent 3672 ABSTRACT False 3673 PROPERTIES GroupComponent[ref SimplePolicyAction[0..n]] 3674 PartComponent[ref PolicyValue[1..1] ] 3676 The reference property "GroupComponent" is inherited from 3677 PolicyComponent, and overridden to become an object reference to a 3678 SimplePolicyAction that contains exactly one PolicyValue. Note that for 3679 any single instance of the aggregation class 3680 PolicyValueInSimplePolicyAction, this property is single-valued. The 3681 [0..n] cardinality indicates that there may be 0, 1, or more 3682 SimplePolicyAction objects that contain any given policy value object. 3684 The reference property "PartComponent" is inherited from PolicyComponent, 3685 and overridden to become an object reference to a PolicyValue that is 3686 defined within the scope of a SimplePolicyAction. Note that for any 3687 single instance of the association class PolicyValueInSimplePolicyAction, 3688 this property (like all reference properties) is single-valued. The 3689 [1..1] cardinality indicates that a SimplePolicyAction must have exactly 3690 one policy value defined within its scope in order to be meaningful. 3692 6.17. The Association "ReusablePolicy" 3694 The association ReusablePolicy makes it possible to include any subclass 3695 of the abstract class "Policy" in a ReusablePolicyContainer. 3697 NAME ReusablePolicy 3698 DESCRIPTION A class representing the inclusion of a reusable 3699 policy element in a ReusablePolicyContainer. Reusable 3700 elements may be PolicyGroups, PolicyRules, 3701 PolicyConditions, PolicyActions, PolicyVariables, 3702 PolicyValues, or instances of any other subclasses of 3703 the abstract class Policy. 3704 DERIVED FROM PolicyInSystem 3705 ABSTRACT FALSE 3706 PROPERTIES Antecedent[ref ReusablePolicyContainer[0..1]] 3708 6.18. Deprecate PCIM's "PolicyConditionInPolicyRepository" 3710 NAME PolicyConditionInPolicyRepository 3711 DEPRECATED FOR ReusablePolicy 3712 DESCRIPTION A class representing the inclusion of a reusable 3713 PolicyCondition in a PolicyRepository. 3714 DERIVED FROM PolicyInSystem 3715 ABSTRACT FALSE 3716 PROPERTIES Antecedent[ref PolicyRepository[0..1]] 3717 Dependent[ref PolicyCondition[0..n]] 3718 6.19. Deprecate PCIM's "PolicyActionInPolicyRepository" 3720 NAME PolicyActionInPolicyRepository 3721 DEPRECATED FOR ReusablePolicy 3722 DESCRIPTION A class representing the inclusion of a reusable 3723 PolicyAction in a PolicyRepository. 3724 DERIVED FROM PolicyInSystem 3725 ABSTRACT FALSE 3726 PROPERTIES Antecedent[ref PolicyRepository[0..1]] 3727 Dependent[ref PolicyAction[0..n]] 3729 6.20. The Association ExpectedPolicyValuesForVariable 3731 This association links a PolicyValue object to a PolicyVariable object, 3732 modeling the set of expected values for that PolicyVariable. Using this 3733 association, a variable (instance) may be constrained to be bound- 3734 to/assigned only a set of allowed values. For example, modeling an 3735 enumerated source port variable, one creates an instance of the 3736 PolicySourcePortVariable class and associates with it the set of values 3737 (integers) representing the allowed enumeration, using appropriate number 3738 of instances of the ExpectedPolicyValuesForVariable association. 3740 Note that a single variable instance may be constrained by any number of 3741 values, and a single value may be used to constrain any number of 3742 variables. These relationships are manifested by the n-to-m cardinality 3743 of the association. 3745 The purpose of this association is to support validation of simple policy 3746 conditions and simple policy actions, prior to their deployment to an 3747 enforcement point. This association, and the PolicyValue object that it 3748 refers to, plays no role when a PDP or a PEP is evaluating a simple 3749 policy condition, or executing a simple policy action. See Section 4.8.3 3750 for more details on this point. 3752 The class definition for the association is as follows: 3754 NAME ExpectedPolicyValuesForVariable 3755 DESCRIPTION A class representing the association of a set of 3756 expected values to a variable object. 3757 DERIVED FROM Dependency 3758 ABSTRACT FALSE 3759 PROPERTIES Antecedent [ref PolicyVariable[0..n]] 3760 Dependent [ref PolicyValue [0..n]] 3762 The reference property Antecedent is inherited from Dependency. Its type 3763 and cardinality are overridden to provide the semantics of a variable 3764 optionally having value constraints. The [0..n] cardinality indicates 3765 that any number of variables may be constrained by a given value. 3767 The reference property "Dependent" is inherited from Dependency, and 3768 overridden to become an object reference to a PolicyValue representing 3769 the values that a particular PolicyVariable can have. The [0..n] 3770 cardinality indicates that a given policy variable may have 0, 1 or more 3771 than one PolicyValues defined to model the set(s) of values that the 3772 policy variable can take. 3774 6.21. The Aggregation "ContainedDomain" 3776 The aggregation ContainedDomain provides a means of nesting of one 3777 ReusablePolicyContainer inside another one. The aggregation is defined 3778 at the level of ReusablePolicyContainer's superclass, AdminDomain, to 3779 give it applicability to areas other than Core Policy. 3781 NAME ContainedDomain 3782 DESCRIPTION A class representing the aggregation of lower level 3783 administrative domains by a higher-level AdminDomain. 3784 DERIVED FROM SystemComponent 3785 ABSTRACT FALSE 3786 PROPERTIES GroupComponent[ref AdminDomain [0..n]] 3787 PartComponent[ref AdminDomain [0..n]] 3789 6.22. Deprecate PCIM's "PolicyRepositoryInPolicyRepository" 3791 NAME PolicyRepositoryInPolicyRepository 3792 DEPRECATED FOR ContainedDomain 3793 DESCRIPTION A class representing the aggregation of 3794 PolicyRepositories by a higher-level PolicyRepository. 3795 DERIVED FROM SystemComponent 3796 ABSTRACT FALSE 3797 PROPERTIES GroupComponent[ref PolicyRepository[0..n]] 3798 PartComponent[ref PolicyRepository[0..n]] 3800 6.23. The Aggregation "EntriesInFilterList" 3802 This aggregation is a specialization of the Component aggregation; it is 3803 used to define a set of filter entries (subclasses of FilterEntryBase) 3804 that are aggregated by a FilterList. 3806 The cardinalities of the aggregation itself are 0..1 on the FilterList 3807 end, and 0..n on the FilterEntryBase end. Thus in the general case, a 3808 filter entry can exist without being aggregated into any FilterList. 3809 However, the only way a filter entry can figure in the PCIMe model is by 3810 being aggregated into a FilterList by this aggregation. 3812 The class definition for the aggregation is as follows: 3814 NAME EntriesInFilterList 3815 DESCRIPTION An aggregation used to define a set of 3816 filter entries (subclasses of 3817 FilterEntryBase) that are aggregated by 3818 a particular FilterList. 3819 DERIVED FROM Component 3820 ABSTRACT False 3821 PROPERTIES GroupComponent[ref 3822 FilterList[0..1]], 3823 PartComponent[ref 3824 FilterEntryBase[0..n], 3825 EntrySequence 3827 6.23.1. The Reference GroupComponent 3829 This property is overridden in this aggregation to represent an object 3830 reference to a FilterList object (instead of to the more generic 3831 ManagedSystemElement object defined in its superclass). It also 3832 restricts the cardinality of the aggregate to 0..1 (instead of the more 3833 generic 0-or-more), representing the fact that a filter entry always 3834 exists within the context of at most one FilterList. 3836 6.23.2. The Reference PartComponent 3838 This property is overridden in this aggregation to represent an object 3839 reference to a FilterEntryBase object (instead of to the more generic 3840 ManagedSystemElement object defined in its superclass). This object 3841 represents a single filter entry, which may be aggregated with other 3842 filter entries to form the FilterList. 3844 6.23.3. The Property EntrySequence 3846 An unsigned 16-bit integer indicating the order of the filter entry 3847 relative to all others in the FilterList. The default value '0' 3848 indicates that order is not significant, because the entries in this 3849 FilterList are ANDed together. 3851 6.24. The Aggregation "ElementInPolicyRoleCollection" 3853 The following aggregation is used to associate ManagedElements with a 3854 PolicyRoleCollection object that represents a role played by these 3855 ManagedElements. 3857 NAME ElementInPolicyRoleCollection 3858 DESCRIPTION A class representing the inclusion of a ManagedElement 3859 in a collection, specified as having a given role. 3860 All the managed elements in the collection share the 3861 same role. 3862 DERIVED FROM MemberOfCollection 3863 ABSTRACT FALSE 3864 PROPERTIES Collection[ref PolicyRoleCollection [0..n]] 3865 Member[ref ManagedElement [0..n]] 3867 6.25. The Weak Association "PolicyRoleCollectionInSystem" 3869 A PolicyRoleCollection is defined within the scope of a System. This 3870 association links a PolicyRoleCollection to the System in whose scope it 3871 is defined. 3873 When associating a PolicyRoleCollection with a System, this should be 3874 done consistently with the system that scopes the policy rules/groups 3875 that are applied to the resources in that collection. A 3876 PolicyRoleCollection is associated with the same system as the applicable 3877 PolicyRules and/or PolicyGroups, or to a System higher in the tree formed 3878 by the SystemComponent association. 3880 The class definition for the association is as follows: 3882 NAME PolicyRoleCollectionInSystem 3883 DESCRIPTION A class representing the fact that a 3884 PolicyRoleCollection is defined within the scope of a 3885 System. 3886 DERIVED FROM Dependency 3887 ABSTRACT FALSE 3888 PROPERTIES Antecedent[ref System[1..1]] 3889 Dependent[ref PolicyRoleCollection[weak]] 3891 The reference property Antecedent is inherited from Dependency, and 3892 overridden to become an object reference to a System, and to restrict its 3893 cardinality to [1..1]. It serves as an object reference to a System that 3894 provides a scope for one or more PolicyRoleCollections. Since this is a 3895 weak association, the cardinality for this object reference is always 1, 3896 that is, a PolicyRoleCollection is always defined within the scope of 3897 exactly one System. 3899 The reference property Dependent is inherited from Dependency, and 3900 overridden to become an object reference to a PolicyRoleCollection 3901 defined within the scope of a System. Note that for any single instance 3902 of the association class PolicyRoleCollectionInSystem, this property 3903 (like all Reference properties) is single-valued. The [0..n] cardinality 3904 indicates that a given System may have 0, 1, or more than one 3905 PolicyRoleCollections defined within its scope. 3907 7. Intellectual Property 3909 The IETF takes no position regarding the validity or scope of any 3910 intellectual property or other rights that might be claimed to pertain to 3911 the implementation or use of the technology described in this document or 3912 the extent to which any license under such rights might or might not be 3913 available; neither does it represent that it has made any effort to 3914 identify any such rights. Information on the IETF's procedures with 3915 respect to rights in standards-track and standards-related documentation 3916 can be found in BCP-11. 3918 Copies of claims of rights made available for publication and any 3919 assurances of licenses to be made available, or the result of an attempt 3920 made to obtain a general license or permission for the use of such 3921 proprietary rights by implementers or users of this specification can be 3922 obtained from the IETF Secretariat. 3924 The IETF invites any interested party to bring to its attention any 3925 copyrights, patents or patent applications, or other proprietary rights 3926 which may cover technology that may be required to practice this 3927 standard. Please address the information to the IETF Executive Director. 3929 8. Acknowledgements 3931 The starting point for this document was PCIM itself [3], and the first 3932 three submodels derived from it [5], [6], [7]. The authors of these 3933 documents created the extensions to PCIM, and asked the questions about 3934 PCIM, that are reflected in PCIMe. 3936 9. Security Considerations 3938 The Policy Core Information Model (PCIM) [3] describes the general 3939 security considerations related to the general core policy model. The 3940 extensions defined in this document do not introduce any additional 3941 considerations related to security. 3943 10. References 3945 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 3946 Levels", BCP 14, RFC 2119, March 1997. 3948 [2] Hovey, R., and S. Bradner, "The Organizations Involved in the IETF 3949 Standards Process", BCP 11, RFC 2028, October 1996. 3951 [3] Strassner, J., and E. Ellesson, B. Moore, A. Westerinen, "Policy Core 3952 Information Model -- Version 1 Specification", RFC 3060, February 3953 2001. 3955 [4] Distributed Management Task Force, Inc., "DMTF Technologies: CIM 3956 Standards � CIM Schema: Version 2.5", available at 3957 http://www.dmtf.org/standards/cim_schema_v25.php. 3959 [5] Snir, Y., and Y. Ramberg, J. Strassner, R. Cohen, "Policy QoS 3960 Information Model", work in progress, draft-ietf-policy-qos-info- 3961 model-04.txt, July 2001. 3963 [6] Jason, J., and L. Rafalow, E. Vyncke, "IPsec Configuration Policy 3964 Model", work in progress, draft-ietf-ipsp-config-policy-model-03.txt, 3965 July 2001. 3967 [7] Chadha, R., and M. Brunner, M. Yoshida, J. Quittek, G. Mykoniatis, A. 3968 Poylisher, R. Vaidyanathan, A. Kind, F. Reichmeyer, "Policy Framework 3969 MPLS Information Model for QoS and TE", work in progress, draft- 3970 chadha-policy-mpls-te-01.txt, December 2000. 3972 [8] Crocker, D., and P. Overell, "Augmented BNF for Syntax Specifications: 3973 ABNF", RFC 2234, November 1997. 3975 [9] P. Mockapetris, "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION", RFC 3976 1035, November 1987. 3978 [10] R. Hinden, S. Deering, "IP Version 6 Addressing Architecture", RFC 3979 2373, July 1998. 3981 [11] M. Wahl, A. Coulbeck, "Lightweight Directory Access Protocol (v3): 3982 Attribute Syntax Definitions", RFC 2252. 3984 [12] A. Westerinen, et al., "Terminology for Policy-Based Management", 3985 , July 2001. 3987 [13] S. Waldbusser, and J. Saperia, T. Hongal, "Policy Based Management 3988 MIB", , June 2001. 3990 [14] B. Moore, and D. Durham, J. Halpern, J. Strassner, A. Westerinen, W. 3991 Weiss, "Information Model for Describing Network Device QoS Datapath 3992 Mechanisms", , July 3993 2001. 3995 11. Authors' Addresses 3997 Bob Moore 3998 IBM Corporation, BRQA/502 3999 4205 S. Miami Blvd. 4000 Research Triangle Park, NC 27709 4001 Phone: +1 919-254-4436 4002 Fax: +1 919-254-6243 4003 E-mail: remoore@us.ibm.com 4005 Lee Rafalow 4006 IBM Corporation, BRQA/502 4007 4205 S. Miami Blvd. 4008 Research Triangle Park, NC 27709 4009 Phone: +1 919-254-4455 4010 Fax: +1 919-254-6243 4011 E-mail: rafalow@us.ibm.com 4013 Yoram Ramberg 4014 Cisco Systems 4015 4 Maskit Street 4016 Herzliya Pituach, Israel 46766 4017 Phone: +972-9-970-0081 4018 Fax: +972-9-970-0219 4019 E-mail: yramberg@cisco.com 4021 Yoram Snir 4022 Cisco Systems 4023 4 Maskit Street 4024 Herzliya Pituach, Israel 46766 4025 Phone: +972-9-970-0085 4026 Fax: +972-9-970-0366 4027 E-mail: ysnir@cisco.com 4029 Andrea Westerinen 4030 Cisco Systems 4031 Building 20 4032 725 Alder Drive 4033 Milpitas, CA 95035 4034 Phone: +1-408-853-8294 4035 Fax: +1-408-527-6351 4036 E-mail: andreaw@cisco.com 4038 Ritu Chadha 4039 Telcordia Technologies 4040 MCC 1J-218R 4041 445 South Street 4042 Morristown NJ 07960. 4043 Phone: +1-973-829-4869 4044 Fax: +1-973-829-5889 4045 E-mail: chadha@research.telcordia.com 4047 Marcus Brunner 4048 NEC Europe Ltd. 4049 C&C Research Laboratories 4050 Adenauerplatz 6 4051 D-69115 Heidelberg, Germany 4052 Phone: +49 (0)6221 9051129 4053 Fax: +49 (0)6221 9051155 4054 E-mail: brunner@ccrle.nec.de 4056 Ron Cohen 4057 Ntear LLC 4058 Phone: 4059 Fax: 4060 E-mail: ronc@ntear.com 4062 John Strassner 4063 INTELLIDEN, Inc. 4064 90 South Cascade Avenue 4065 Colorado Springs, CO 80903 4066 Phone: +1-719-785-0648 4067 E-mail: john.strassner@intelliden.com 4069 12. Full Copyright Statement 4071 Copyright (C) The Internet Society (2001). All Rights Reserved. 4073 This document and translations of it may be copied and furnished to 4074 others, and derivative works that comment on or otherwise explain it or 4075 assist in its implementation may be prepared, copied, published and 4076 distributed, in whole or in part, without restriction of any kind, 4077 provided that the above copyright notice and this paragraph are included 4078 on all such copies and derivative works. However, this document itself 4079 may not be modified in any way, such as by removing the copyright notice 4080 or references to the Internet Society or other Internet organizations, 4081 except as needed for the purpose of developing Internet standards in 4082 which case the procedures for copyrights defined in the Internet 4083 Standards process must be followed, or as required to translate it into 4084 languages other than English. 4086 The limited permissions granted above are perpetual and will not be 4087 revoked by the Internet Society or its successors or assigns. 4089 This document and the information contained herein is provided on an "AS 4090 IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK 4091 FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT 4092 LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT 4093 INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR 4094 FITNESS FOR A PARTICULAR PURPOSE. 4096 13. Appendix A: Closed Issues 4098 EDITOR'S NOTE: The following list captures the major technical issues 4099 that were resolved during the course of progressing PCIMe from initial 4100 draft to Proposed Standard. This appendix will be removed for submission 4101 to the RFC Editor (unless there is a consensus to preserve it in the 4102 RFC), but it should be archived somewhere. 4104 1. Unrestricted use of DNF/CNF for CompoundPolicyConditions. 4105 Alternative: for the conditions aggregated by a 4106 CompoundPolicyCondition, allow only ANDing, with negation of 4107 individual conditions. Note that this is sufficient to build 4108 multi-field packet filters from single-field 4109 SimplePolicyConditions. 4111 RESOLUTION: The same DNF/CNF capabilities present for aggregating 4112 PolicyConditions into a PolicyRule have been retained for 4113 aggregating PolicyConditions into a CompoundPolicyCondition. 4115 2. For a PolicyVariable in a SimplePolicyCondition, restrict the set 4116 of possible values both via associated PolicyValue objects (tied 4117 in with the ExpectedPolicyValuesForVariable association) and via 4118 the ValueTypes property in the PolicyVariable class. Alternative: 4119 restrict values only via associated PolicyValue objects. 4121 RESOLUTION: PCIMe continues to allow both mechanisms for 4122 restricting the values of a PolicyVariable. 4124 3. Transactional semantics, including rollback, for the 4125 ExecutionStrategy property in PolicyRule and in 4126 CompoundPolicyAction. Alternative: have only 'Do until success' 4127 and 'Do all'. 4129 RESOLUTION: No transactional semantics for action execution. The 4130 value 'Mandatory Do All(1)' has been removed from the two 4131 ExecutionStrategy properties. 4133 4. Stating that CompoundFilterConditions are the preferred way to do 4134 packet filtering in a PolicyCondition. Alternative: make 4135 CompoundFilterConditions and FilterEntries available to submodels, 4136 with no stated (or implied) preference. 4138 RESOLUTION: Recommendations for use of CompoundFilterConditions 4139 and FilterEntries are retained, but they have been recast 4140 slightly. CompoundFilterConditions are now positioned as the 4141 recommended approach for domain-level models. FilterEntries are 4142 the recommended approach for device-level models. 4144 5. Prohibiting equal values for Priority within a PolicySet. 4145 Alternative: allow equal values, with resulting indeterminacy in 4146 PEP behavior. 4148 RESOLUTION: PCIMe will continue to prohibit equal Priority values. 4150 6. Modeling a SimplePolicyAction with just a related PolicyVariable 4151 and PolicyValue -- the "set" or "apply" operation is implicit. 4152 Alternative: include an Operation property in SimplePolicyAction, 4153 similar to the Operation property in SimplePolicyCondition. 4155 RESOLUTION: This issue has been resolved by a change in the 4156 opposite direction. The operations are now implicit for BOTH 4157 SimplePolicyCondition and SimplePolicyAction. See Sections 4.8.3 4158 and 4.8.4, respectively, for discussions of 4159 SimplePolicyCondition's implicit MATCH operator and 4160 SimplePolicyAction's implicit SET operator. 4162 7. Representation of PolicyValues: should values like IPv4 addresses 4163 be represented only as strings (as in LDAP), or natively (e.g., an 4164 IPv4 address would be a four-octet field) with mappings to other 4165 representations such as strings? 4167 RESOLUTION: Mappings have been eliminated. Each value type has a 4168 single representation specified for it. 4170 8. The nesting of rules and groups within rules introduces 4171 significant change and complexity in the model. This nesting 4172 introduces program state (procedural language) into the model 4173 (heretofore a declarative model) as well as implicit hierarchical 4174 contexts on which the rules operate. These require a much more 4175 sophisticated rule-evaluation engine than in the past. 4177 Alternative: Maintain the declarative model, by prohibiting 4178 program state in rule evaluation (i.e., no rules within rules). 4180 RESOLUTION: Nesting of rules and groups within rules has been 4181 retained, but with a significant new limitation: actions 4182 associated with a rule do not have side effects that would impact 4183 condition evaluation for subsequent rules. "Subsequent rules" 4184 here includes both rules nested within the rule whose actions are 4185 under discussion, and rules at the same nesting level as this rule 4186 that are evaluated after it. Note that it has been a feature of 4187 PCIM (RFC 3060) all along that condition evaluation has no side 4188 effects that would influence condition evaluation for subsequent 4189 rules. 4191 There is also one modeling detail associated with nesting that has 4192 been changed. Rather than having separate aggregations 4193 (PolicyGroupInPolicyGroup, etc.) for each of the four nesting 4194 varieties, the single aggregation PolicySetComponent is now used 4195 as a concrete aggregation class. 4197 9. Need to specify a join algorithm for disjoint rule sets. 4199 RESOLUTION: PCIMe now states that for different functional domains 4200 (e.g., QoS and IKE), there is no join algorithm. Each domain, in 4201 effect, has its own rule engine, which operates independently of 4202 the other domains' engine(s). Within a functional domain, 4203 disjoint PolicySets are joined by the Priority property in the 4204 PolicySetInSystem association. In this case the decision strategy 4205 is specified to be FirstMatching. 4207 10. Clarify PolicyImplicitVariables. 4209 RESOLUTION: Each subclass of PolicyImplicitVariable will identify 4210 the exact source of the variable data. For example, there will be 4211 a subclass of PolicyImplicitVariable that specifically identifies 4212 the IPv4 source address in the outermost packet header. IPv4 and 4213 IPv6 addresses will require separate subclasses of 4214 PolicyImplicitVariable. We understand the downside of this 4215 approach: a potential explosion in the number of subclasses of 4216 PolicyImplicitVariable. 4218 11. Clarify PolicyExplicitVariables. 4220 NON-RESOLUTION (in PCIMe-01): This issue is still not resolved at 4221 all. The authors continue to believe that we need the capability 4222 of indicating that a condition should compare against (or an 4223 action should set) a particular property in a particular object 4224 instance. But we do not believe that the current mechanism of 4225 specifying a target object class and property name is sufficient. 4226 For the next version of PCIMe, we need to either find a way to 4227 make this work in general; or find a way to make it work in some 4228 cases, and then describe clearly what these cases are; or remove 4229 PolicyExplicitVariables from PCIMe entirely. 4231 RESOLUTION (in PCIMe-02): From the list of choices above, we took 4232 the path of making explicit variables work in a specific case, and 4233 indicating clearly that they work only in this case. See section 4234 4.8.6