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Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: If UDP is selected as the transport protocol, the commonPropertiesID Template Withdraw Messages MUST not be used, as this method is inefficient due to the unreliable nature of UDP. -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (May 21, 2007) is 6185 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-26) exists of draft-ietf-ipfix-protocol-24 == Outdated reference: A later version (-09) exists of draft-ietf-psamp-protocol-07 == Outdated reference: A later version (-12) exists of draft-ietf-ipfix-as-11 == Outdated reference: A later version (-11) exists of draft-ietf-psamp-info-05 == Outdated reference: A later version (-11) exists of draft-ietf-psamp-sample-tech-07 == Outdated reference: A later version (-13) exists of draft-ietf-psamp-framework-11 -- Obsolete informational reference (is this intentional?): RFC 2960 (Obsoleted by RFC 4960) Summary: 1 error (**), 0 flaws (~~), 9 warnings (==), 9 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPFIX Working Group E. Boschi 3 Internet-Draft Hitachi Europe 4 Intended status: Informational L. Mark 5 Expires: November 22, 2007 Fraunhofer FOKUS 6 B. Claise 7 Cisco Systems, Inc. 8 May 21, 2007 10 Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet 11 Sampling (PSAMP) Reports 12 draft-ietf-ipfix-reducing-redundancy-04.txt 14 Status of this Memo 16 By submitting this Internet-Draft, each author represents that any 17 applicable patent or other IPR claims of which he or she is aware 18 have been or will be disclosed, and any of which he or she becomes 19 aware will be disclosed, in accordance with Section 6 of BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF), its areas, and its working groups. Note that 23 other groups may also distribute working documents as Internet- 24 Drafts. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and may be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference 29 material or to cite them other than as "work in progress." 31 The list of current Internet-Drafts can be accessed at 32 http://www.ietf.org/ietf/1id-abstracts.txt. 34 The list of Internet-Draft Shadow Directories can be accessed at 35 http://www.ietf.org/shadow.html. 37 This Internet-Draft will expire on November 22, 2007. 39 Copyright Notice 41 Copyright (C) The IETF Trust (2007). 43 Abstract 45 This document describes a bandwidth saving method for exporting flow 46 or packet information using the IP Flow Information Export (IPFIX) 47 protocol. As the Packet Sampling (PSAMP) protocol is based on IPFIX, 48 these considerations are valid for PSAMP exports as well. 50 This method works by separating information common to several flow 51 records from information specific to an individual flow record. 52 Common flow information is exported only once in a data record 53 defined by an option template, while the rest of the specific flow 54 information is associated with the common information via a unique 55 identifier. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 1.1. IPFIX Documents Overview . . . . . . . . . . . . . . . . . 3 61 1.2. PSAMP Documents Overview . . . . . . . . . . . . . . . . . 4 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 63 2.1. Terminology Summary Table . . . . . . . . . . . . . . . . 8 64 2.2. IPFIX Flows versus PSAMP Packets . . . . . . . . . . . . . 9 65 3. Specifications for bandwidth saving information export . . . . 9 66 3.1. Problem Statement and High Level Solution . . . . . . . . 9 67 3.2. Data Reduction technique . . . . . . . . . . . . . . . . . 11 68 4. Transport Protocol Choice . . . . . . . . . . . . . . . . . . 12 69 4.1. PR-SCTP . . . . . . . . . . . . . . . . . . . . . . . . . 12 70 4.2. UDP . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 71 4.3. TCP . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 72 5. commonPropertiesID Management . . . . . . . . . . . . . . . . 13 73 6. The Collecting Process Side . . . . . . . . . . . . . . . . . 14 74 6.1. UDP . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 75 6.2. TCP . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 76 7. Advanced Techniques . . . . . . . . . . . . . . . . . . . . . 16 77 7.1. Multiple Data Reduction . . . . . . . . . . . . . . . . . 16 78 7.2. Cascading Common Properties . . . . . . . . . . . . . . . 19 79 8. Export and Evaluation Considerations . . . . . . . . . . . . . 19 80 8.1. Transport Protocol Choice . . . . . . . . . . . . . . . . 20 81 8.2. Reduced Size Encoding . . . . . . . . . . . . . . . . . . 20 82 8.3. Efficiency Gain . . . . . . . . . . . . . . . . . . . . . 20 83 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 84 10. Security Considerations . . . . . . . . . . . . . . . . . . . 21 85 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21 86 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22 87 12.1. Normative References . . . . . . . . . . . . . . . . . . . 22 88 12.2. Informative References . . . . . . . . . . . . . . . . . . 22 89 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 23 90 A.1. Per Flow Data Reduction . . . . . . . . . . . . . . . . . 23 91 A.2. Per Packet Data Reduction . . . . . . . . . . . . . . . . 27 92 A.3. commonPropertiesID Template Withdrawal Message . . . . . . 30 93 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31 94 Intellectual Property and Copyright Statements . . . . . . . . . . 32 96 1. Introduction 98 The IPFIX working group has specified a protocol to export IP Flow 99 information [I-D.ietf-ipfix-protocol]. This protocol is designed to 100 export information about IP traffic flows and related measurement 101 data, where a flow is defined by a set of key attributes (e.g. source 102 and destination IP address, source and destination port, etc.). 103 However, thanks to its template mechanism, the IPFIX protocol can 104 export any type of information, as long as the information element is 105 specified in the IPFIX Information Model [I-D.ietf-ipfix-protocol] or 106 registered with IANA. 108 Regardless of the fields content, flow records with common properties 109 export the same fields in every single data record. These common 110 properties may represent values common to a collection of flows or 111 packets, or values that are invariant over time. Note that the 112 common properties don't represent the list of flow keys, which are 113 used to define a flow definition: however, the common properties may 114 contain some of the flow keys. The reduction of redundant data from 115 the export stream can result in a significant reduction of the 116 transferred data. 118 This draft specifies a way to export these invariant or common 119 properties only once, while the rest of the flow specific properties 120 are exported in regular data records. Unique common properties 121 identifiers are used to link data records and the common attributes. 123 The proposed method is applicable to IPFIX flow and to PSAMP per 124 packet information, without any changes to both the IPFIX and PSAMP 125 protocol specifications. 127 1.1. IPFIX Documents Overview 129 The IPFIX Protocol [I-D.ietf-ipfix-protocol] provides network 130 administrators with access to IP flow information. The architecture 131 for the export of measured IP flow information out of an IPFIX 132 exporting process to a collecting process is defined in the IPFIX 133 Architecture [I-D.ietf-ipfix-architecture], per the requirements 134 defined in RFC 3917 [RFC3917]. The IPFIX Architecture 135 [I-D.ietf-ipfix-architecture] specifies how IPFIX data record and 136 templates are carried via a congestion-aware transport protocol from 137 IPFIX exporting processes to IPFIX collecting process. IPFIX has a 138 formal description of IPFIX information elements, their name, type 139 and additional semantic information, as specified in the IPFIX 140 Information Model [I-D.ietf-ipfix-info]. Finally the IPFIX 141 Applicability Statement [I-D.ietf-ipfix-as] describes what type of 142 applications can use the IPFIX protocol and how they can use the 143 information provided. It furthermore shows how the IPFIX framework 144 relates to other architectures and frameworks. 146 1.2. PSAMP Documents Overview 148 The document "A Framework for Packet Selection and Reporting" 149 [I-D.ietf-psamp-framework], describes the PSAMP framework for network 150 elements to select subsets of packets by statistical and other 151 methods, and to export a stream of reports on the selected packets to 152 a collector. The set of packet selection techniques (sampling, 153 filtering, and hashing) supported by PSAMP are described in "Sampling 154 and Filtering Techniques for IP Packet Selection" 155 [I-D.ietf-psamp-sample-tech]. The PSAMP protocol 156 [I-D.ietf-psamp-protocol] specifies the export of packet information 157 from a PSAMP exporting process to a PSAMP collecting process. Like 158 IPFIX, PSAMP has a formal description of its information elements, 159 their name, type and additional semantic information. The PSAMP 160 information model is defined in [I-D.ietf-psamp-info]. Finally 161 [I-D.ietf-psamp-mib] describes the PSAMP Management Information Base. 163 2. Terminology 165 The terms in this section are in line with the IPFIX terminology 166 section in the IPFIX [I-D.ietf-ipfix-protocol], and PSAMP 167 [I-D.ietf-psamp-protocol] protocol specifications. Note that this 168 document selected the IPFIX definition of the term Exporting Process 169 [I-D.ietf-ipfix-protocol], as this definition is more generic than 170 the PSAMP definition [I-D.ietf-psamp-protocol]. 172 Observation Point: An Observation Point is a location in the 173 network where IP packets can be observed. Examples include: a 174 line to which a probe is attached, a shared medium, such as an 175 Ethernet-based LAN, a single port of a router, or a set of 176 interfaces (physical or logical) of a router. Note that every 177 Observation Point is associated with an Observation Domain 178 (defined below), and that one Observation Point may be a superset 179 of several other Observation Points. For example one Observation 180 Point can be an entire line card. That would be the superset of 181 the individual Observation Points at the line card's interfaces. 183 Observation Domain: An Observation Domain is the largest set of 184 Observation Points for which Flow information can be aggregated by 185 a Metering Process. For example, a router line card may be an 186 Observation Domain if it is composed of several interfaces, each 187 of which is an Observation Point. In the IPFIX Message it 188 generates, the Observation Domain includes its Observation Domain 189 ID, which is unique per Exporting Process. That way, the 190 Collecting Process can identify the specific Observation Domain 191 from the Exporter that sends the IPFIX Messages. Every 192 Observation Point is associated with an Observation Domain. It is 193 RECOMMENDED that Observation Domain IDs are also unique per IPFIX 194 Device. 196 IP Traffic Flow or Flow: There are several definitions of the term 197 'flow' being used by the Internet community. Within the context 198 of IPFIX we use the following definition: 200 A Flow is defined as a set of IP packets passing an Observation 201 Point in the network during a certain time interval. All packets 202 belonging to a particular Flow have a set of common properties. 203 Each property is defined as the result of applying a function to 204 the values of: 206 1. one or more packet header field (e.g. destination IP address), 207 transport header field (e.g. destination port number), or 208 application header field (e.g. RTP header fields [RFC3550]) 210 2. one or more characteristics of the packet itself (e.g. number 211 of MPLS labels, etc...) 213 3. one or more of fields derived from packet treatment (e.g. next 214 hop IP address, the output interface, etc...) 216 A packet is defined to belong to a Flow if it completely satisfies 217 all the defined properties of the Flow. 219 This definition covers the range from a Flow containing all 220 packets observed at a network interface to a Flow consisting of 221 just a single packet between two applications. It includes 222 packets selected by a sampling mechanism. 224 Flow Record: A Flow Record contains information about a specific 225 Flow that was observed at an Observation Point. A Flow Record 226 contains measured properties of the Flow (e.g. the total number of 227 bytes for all the Flow's packets) and usually characteristic 228 properties of the Flow (e.g. source IP address). 230 Metering Process: The Metering Process generates Flow Records. 231 Inputs to the process are packet headers and characteristics 232 observed at an Observation Point, and packet treatment at the 233 Observation Point (for example the selected output interface). 235 The Metering Process consists of a set of functions that includes 236 packet header capturing, timestamping, sampling, classifying, and 237 maintaining Flow Records. 239 The maintenance of Flow Records may include creating new records, 240 updating existing ones, computing Flow statistics, deriving 241 further Flow properties, detecting Flow expiration, passing Flow 242 Records to the Exporting Process, and deleting Flow Records. 244 Exporting Process: The Exporting Process sends Flow Records to one 245 or more Collecting Processes. The Flow Records are generated by 246 one or more Metering Processes. 248 Exporter: A device which hosts one or more Exporting Processes is 249 termed an Exporter. 251 IPFIX Device: An IPFIX Device hosts at least one Exporting Process. 252 It may host further Exporting processes and arbitrary numbers of 253 Observation Points and Metering Process. 255 Collecting Process: A Collecting Process receives Flow Records from 256 one or more Exporting Processes. The Collecting Process might 257 process or store received Flow Records, but such actions are out 258 of scope for this document. 260 Template: Template is an ordered sequence of (type, length) pairs, 261 used to completely specify the structure and semantics of a 262 particular set of information that needs to be communicated from 263 an IPFIX Device to a Collector. Each Template is uniquely 264 identifiable by means of a Template ID. 266 Template Record: A Template Record defines the structure and 267 interpretation of fields in a Data Record. 269 Data Record: A Data Record is a record that contains values of the 270 parameters corresponding to a Template Record. 272 Options Template Record: An Options Template Record is a Template 273 Record that defines the structure and interpretation of fields in 274 a Data Record, including defining how to scope the applicability 275 of the Data Record. 277 Set: Set is a generic term for a collection of records that have a 278 similar structure. In an IPFIX Message, one or more Sets follow 279 the Message Header. There are three different types of Sets: 280 Template Set, Options Template Set, and Data Set. 282 Template Set: A Template Set is a collection of one or more 283 Template Records that have been grouped together in an IPFIX 284 Message. 286 Options Template Set: An Options Template Set is a collection of 287 one or more Options Template Records that have been grouped 288 together in an IPFIX Message. 290 Data Set: A Data Set is one or more Data Records, of the same type, 291 that are grouped together in an IPFIX Message. Each Data Record 292 is previously defined by a Template Record or an Options Template 293 Record. 295 Information Element: An Information Element is a protocol and 296 encoding independent description of an attribute which may appear 297 in an IPFIX Record. The IPFIX information model 298 [I-D.ietf-ipfix-info] defines the base set of Information Elements 299 for IPFIX. The type associated with an Information Element 300 indicates constraints on what it may contain and also determines 301 the valid encoding mechanisms for use in IPFIX. 303 Observed Packet Stream: The Observed Packet Stream is the set of 304 all packets observed at the Observation Point. 306 Packet content: The packet content denotes the union of the packet 307 header (which includes link layer, network layer and other 308 encapsulation headers) and the packet payload. 310 Selection Process: A Selection Process takes the Observed Packet 311 Stream as its input and selects a subset of that stream as its 312 output. 314 Selector: A Selector defines the action of a Selection Process on a 315 single packet of its input. If selected, the packet becomes an 316 element of the output Packet Stream. 318 The Selector can make use of the following information in 319 determining whether a packet is selected: 321 1. the Packet Content; 323 2. information derived from the packet's treatment at the 324 Observation Point; 326 3. any selection state that may be maintained by the Selection 327 Process. 329 PSAMP Device: A PSAMP Device is a device hosting at least an 330 Observation Point, a Selection Process and an Exporting Process. 331 Typically, corresponding Observation Point(s), Selection 332 Process(es) and Exporting Process(es) are co-located at this 333 device, for example at a router. 335 Filtering: A filter is a Selector that selects a packet 336 deterministically based on the Packet Content, or its treatment, 337 or functions of these occurring in the Selection State. Examples 338 include field match Filtering, and Hash-based Selection. 340 Transport Session: In SCTP, the transport session is known as the 341 SCTP association, which is uniquely identified by the SCTP 342 endpoints [RFC2960]; in TCP, the transport session is known as the 343 TCP connection, which is uniquely identified by the combination of 344 IP addresses and TCP ports used; In UDP, the transport session is 345 known as the UDP session, which is uniquely identified by the 346 combination of IP addresses and UDP ports used. 348 commonPropertiesID: The commonPropertiesID is an identifier of a 349 set of common properties that is locally unique per Observation 350 Domain and Transport Session. Typically, this Information Element 351 is used to link to information reported in separate Data Records. 352 See the IPFIX information model [I-D.ietf-ipfix-info] for the 353 Information Element definition. 355 Common Properties: Common Properties are a collection of one or 356 more attributes shared by a set of different Flow Records. Each 357 set of Common Properties is uniquely identifiable by means of a 358 commonPropertiesID. 360 Specific Properties: Specific Properties are a collection of one or 361 more attributes reported in a Flow Record that are not included in 362 the Common Properties defined for that Flow Record. 364 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 365 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 366 document are to be interpreted as described in RFC 2119 [RFC2119]. 368 2.1. Terminology Summary Table 370 +------------------+---------------------------------------------+ 371 | | Contents | 372 | +--------------------+------------------------+ 373 | Set | Template | Record | 374 +------------------+--------------------+------------------------+ 375 | Data Set | / | Data Record(s) | 376 +------------------+--------------------+------------------------+ 377 | Template Set | Template Record(s) | / | 378 +------------------+--------------------+------------------------+ 379 | Options Template | Options Template | / | 380 | Set | Record(s) | | 381 +------------------+--------------------+------------------------+ 382 Terminology Summary Table 384 A Data Set is composed of Data Record(s). No Template Record is 385 included. A Template Record or an Options Template Record defines 386 the Data Record. 388 A Template Set contains only Template Record(s). 390 An Options Template Set contains only Options Template Record(s). 392 2.2. IPFIX Flows versus PSAMP Packets 394 As described in the PSAMP protocol specification 395 [I-D.ietf-psamp-protocol], the major difference between IPFIX and 396 PSAMP is that the IPFIX protocol exports Flow Records while the PSAMP 397 protocol exports Packet Records. From a pure export point of view, 398 IPFIX will not distinguish a Flow Record composed of several packets 399 aggregated together from a Flow Record composed of a single packet. 400 So the PSAMP export can be seen as special IPFIX Flow Record 401 containing information about a single packet. 403 For this document clarity, the term Flow Record represents a generic 404 term expressing an IPFIX Flow Record or a PSAMP packet record, as 405 foreseen by its definition. However, when appropriate, a clear 406 distinction between Flow Record or packet Record will be made. 408 3. Specifications for bandwidth saving information export 410 Several Flow Records often share a set of Common Properties. 411 Repeating the information about these Common Properties for every 412 Flow Record introduces a huge amount of redundancy. This document 413 proposes a method to reduce this redundancy. 415 The PSAMP specifications are used for the export of per-packet 416 information, exporting the specific observed packet in an IPFIX Flow 417 Record. This can be considered as a special Flow Record case, 418 composed of a single packet. Therefore, the method described in this 419 document is also applicable to per packet data reduction, e.g. for 420 export of One Way Delay (OWD) measurements (see Appendix), trajectory 421 sampling, etc. 423 3.1. Problem Statement and High Level Solution 425 Consider a set of properties "A", e.g. common sourceAddressA and 426 sourcePortA, equivalent for each Flow Records exported. Figure 2 427 shows how this information is repeated with classical IPFIX Flow 428 Records, expressing the waste of bandwidth to export redundant 429 information. 431 +----------------+-------------+---------------------------+ 432 | sourceAddressA | sourcePortA | | 433 +----------------+-------------+---------------------------+ 434 | sourceAddressA | sourcePortA | | 435 +----------------+-------------+---------------------------+ 436 | sourceAddressA | sourcePortA | | 437 +----------------+-------------+---------------------------+ 438 | sourceAddressA | sourcePortA | | 439 +----------------+-------------+---------------------------+ 440 | ... | ... | ... | 441 +----------------+-------------+---------------------------+ 443 Figure 2: Common and Specific Properties exported together 445 Figure 3 shows how this information is exported when applying the 446 specifications of this document. The Common Properties are separated 447 from the Specific Properties for each Flow Record. The Common 448 Properties would be exported only once in a specific Data Record 449 (defined by an Option Template), while each Flow Record contains a 450 pointer to the Common Properties A, along with its Flow specific 451 information. In order to maintain the relationship between these 452 sets of properties, we introduce indices (in this case: index for 453 properties A) for the Common Properties that are unique for all 454 Common Properties entries within an Observation Domain. The purpose 455 of the indices is to serve as a "key" identifying "rows" of the 456 Common Properties table. The rows are then referenced by the 457 Specific Properties by using the appropriate value for the Common 458 Properties identifier. 460 +------------------------+-----------------+-------------+ 461 | index for properties A | sourceAddressA | sourcePortA | 462 +------------------------+-----------------+-------------+ 463 | ... | ... | ... | 464 +------------------------+-----------------+-------------+ 466 +------------------------+---------------------------+ 467 | index for properties A | | 468 +------------------------+---------------------------+ 469 | index for properties A | | 470 +------------------------+---------------------------+ 471 | index for properties A | | 472 +------------------------+---------------------------+ 473 | index for properties A | | 474 +------------------------+---------------------------+ 475 Figure 3: Common and Specific Properties exported separately 477 This unique export of the Common Properties results in a decrease of 478 the bandwidth requirements for the path between the Exporter and the 479 Collector. 481 3.2. Data Reduction technique 483 The IPFIX protocol [I-D.ietf-ipfix-protocol] is Template based. 484 Templates define how data should be exported, describing data fields 485 together with their type and meaning. IPFIX specifies two types of 486 Templates: the Template Record and the Options Template Record. The 487 difference between the two is that the Options Template Record 488 includes the notion of scope, defining how to scope the applicability 489 of the Data Record. The scope, which is only available in the 490 Options Template Record, gives the context of the reported 491 Information Elements in the Data Records. The Template Records and 492 Options Template Records are necessary to decode the Data Records. 493 Indeed, by only looking at the Data Records themselves, this is 494 impossible to distinguish a Data Record defined by Template Record 495 from a Data Record defined by an Option Template Record. To export 496 information more efficiently, this specification proposes to group 497 Flow Records by their common properties. We define Common Properties 498 as a collection of attributes shared by a set of different Flow 499 Records. 501 An implementation using the proposed specification MUST follow the 502 IPFIX transport protocol specifications defined in the IPFIX protocol 503 [I-D.ietf-ipfix-protocol]. 505 As explained in Figure 4, the information is split into two parts, 506 using two different Data Records. Common Properties MUST be exported 507 via Data Records defined by an Option Template Record. Like Template 508 Records, they MUST be sent only once per SCTP association or TCP 509 connection, and MUST be sent reliably via SCTP if SCTP is the 510 transport protocol. These properties represent values common to 511 several Flow Records (e.g. IP source and destination address). The 512 Common Properties Data Records MUST be sent prior to the 513 corresponding Specific Properties Data Records. The Data Records 514 reporting Specific Properties MUST be associated with the Data 515 Records reporting the Common Properties using a unique identifier for 516 the Common Properties, the commonPropertiesID Information Element 517 [I-D.ietf-ipfix-info]. The commonPropertiesID MUST be exported as 518 the scope in the Options Template Record, and also exported in the 519 associated Template Record. 521 +---------------------------+ +---------------------+ 522 | Common Properties | | Specific Properties | Template 523 | Option Template Record | | Template Record | Definition 524 | | | | 525 | scope: commonPropertiesID | | commonPropertiesID | 526 | Common Properties | | Specific Properties | 527 +------------+--------------+ +---------+-----------+ 528 .............|...............................|....................... 529 | | 530 +------------v-------------+ +----------v----------+ 531 | Common Properties | | Specific Properties |+ Exported 532 | Data Record |------> Data Records || Data 533 +--------------------------+ +---------------------+| Records 534 +---------------------+ 536 Figure 4: Template Record and Data Record dependencies 538 From the IPFIX protocol, there are no differences between the per 539 Flow or per packet data reduction, except maybe the terminology where 540 the Specific Properties could be called packet Specific Properties in 541 the previous figure. 543 4. Transport Protocol Choice 545 This document follows the IPFIX transport protocol specifications 546 defined in the IPFIX protocol [I-D.ietf-ipfix-protocol]. However, 547 depending on the transport protocol choice, this document imposes 548 some more constraints. If PR-SCTP is selected as the IPFIX protocol, 549 the SCTP sub-section specifications MUST be respected. If UDP is 550 selected as the IPFIX protocol, the UDP sub-section specifications 551 MUST be respected. If TCP is selected as the IPFIX protocol, the TCP 552 sub-section specifications MUST be respected. 554 4.1. PR-SCTP 556 The active Common Properties MUST be sent after the SCTP association 557 establishment before the corresponding Specific Properties Data 558 Records. In case of SCTP association re-establishment, all active 559 Common Properties MUST be re-sent before the corresponding Specific 560 Properties Data Records. 562 The Common Properties Data Records MUST be sent reliably. 564 4.2. UDP 566 Common Properties Data Records MUST be re-sent at regular intervals, 567 whose frequency MUST be configurable. The default value for the 568 frequency of Common Properties transmission (refresh timeout) is 10 569 minutes. 571 The Exporting Process SHOULD transmit the Common Properties 572 definition in advance of any Data Record that use these Common 573 Properties, to help ensure that the Collector has the Common 574 Properties definition before receiving the first associated Data 575 Record. 577 If a commonPropertiesID is not used anymore the Exporting Process 578 stops re-sending the related Common Properties Data Record. The old 579 commonPropertiesID MUST NOT be used until its lifetime (see 580 Section 6.1) has expired. 582 4.3. TCP 584 Common Properties MUST be sent after the TCP connection establishment 585 before the corresponding Specific Properties Data Records. In case 586 of TCP connection re-establishment, all active Common Properties MUST 587 be re-sent before the corresponding Specific Properties Data Records. 589 5. commonPropertiesID Management 591 The commonPropertiesId is an identifier of a set of common properties 592 that is locally unique per Observation Domain and Transport Session. 593 The Exporting Process MUST manage the commonPropertiesIDs allocations 594 for its Observation Domains and Transport Session. Different 595 Observation Domains from the same Exporter MAY use the same 596 commonPropertiesID value to refer to different sets of Common 597 Properties. 599 The commonPropertiesID values MAY be assigned sequentially, but it is 600 NOT REQUIRED. Particular commonPropertiesID ranges or values MAY 601 have explicit meanings for the IPFIX Device. For example, 602 commonPropertiesID values may be assigned based on the result of a 603 hash function, etc... 605 Using a 64 bit commonPropertiesID Information Element allows the 606 export of 2**64 active sets of Common Properties, per Observation 607 Domain and per Transport Session. 609 commonPropertiesIDs that are not used anymore SHOULD be withdrawn. 610 The Common Properties ID withdrawal message is a Data Record defined 611 by an Option Template consisting of only one scope field namely the 612 commonPropertiesID (with a type of 137 [I-D.ietf-ipfix-info]) and no 613 non-scope fields. 615 0 1 2 3 616 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 617 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 618 | Set ID = 3 | Length = 14 octets | 619 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 620 | Template ID N | Field Count = 1 | 621 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 622 | Scope Field count = 1 |0| commonPropertiesID = 137 | 623 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 624 | Scope 1 Field Length = 8 | 625 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 627 commonPropertiesID Withdrawal Message 629 If UDP is selected as the transport protocol, the commonPropertiesID 630 Template Withdraw Messages MUST not be used, as this method is 631 inefficient due to the unreliable nature of UDP. 633 6. The Collecting Process Side 635 This section describes the Collecting Process when using SCTP and PR- 636 SCTP as the transport protocol. Any necessary changes to the 637 Collecting Process specifically related to TCP or UDP transport 638 protocols are specified in the subsections. 640 The Collecting Process MUST store the commonPropertiesId information 641 for the duration of the association so that it can interpret the 642 corresponding Data Records that are received in subsequent Data Sets. 643 The Collecting Process can either store the Data Records as they 644 arrive, without reconstructing the initial Flow Record, or 645 reconstruct the initial Flow Record. In the former case, there might 646 be less storage capacity required at the Collector side. In the 647 latter case, the collector job is more complex and time-consuming due 648 to the higher resource demand for record processing in real time. 650 If the Collecting Process has received the Specific Properties Data 651 Record before the associated Common Properties Data Record, the 652 Collecting Process SHOULD store the Specific Properties Data Record 653 and await the retransmission or out-of-order arrival of the Common 654 Properties Data Record. 656 Common Properties IDs are unique per SCTP association and per 657 Observation Domain. If the Collecting Process receives a Common 658 Properties ID which has already been received but which has not 659 previously been withdrawn (i.e. a commonPropertiesID from the same 660 Exporter Observation Domain received on the SCTP association), then 661 the Collecting Process MUST shutdown the association. 663 When an SCTP association is closed, the Collecting Process MUST 664 discard all Common Properties IDs received over that association and 665 stop decoding IPFIX Messages that use those Common Properties IDs. 667 If a Collecting Process receives a Common Properties Withdrawal 668 message, the Collecting Process MUST delete the corresponding Common 669 Properties associated with the specific SCTP association and specific 670 Observation Domain, and stop interpreting Data Records referring to 671 those Common Properties. The receipt of Data Records referring to 672 Common Properties that have been withdrawn MUST be ignored and SHOULD 673 be logged by the Collecting Process. 675 If the Collecting Process receives a Common Properties Withdrawal 676 message for a Common Properties that it has not received before on 677 this SCTP assocation, it MUST reset the SCTP association, discard the 678 IPFIX Message, and SHOULD log the error as it does for malformed 679 IPFIX Messages. 681 6.1. UDP 683 The Collecting Process MUST associate a lifetime with each Common 684 Property received via UDP. Common Properties not refreshed by the 685 Exporting Process within the lifetime are expired at the Collecting 686 Process. 688 If the Common Properties are not refreshed before that lifetime has 689 expired, the Collecting Process MUST discard the corresponding 690 definition of the commonPropertiesID and any current and future 691 associated Data Records. In which case, an alarm MUST be logged. 693 The Collecting Process MUST NOT decode any further Data Records which 694 are associated with the expired Common Properties. If a Common 695 Property is refreshed with a definition that differs from the 696 previous definition, the Collecting Process SHOULD log a warning and 697 replace the previous received Common Property with the new one. The 698 Common Property lifetime at the Collecting Process MUST be at least 3 699 times higher than the refresh timeout of the Template used to export 700 the Common Property definition, configured on the Exporting Process. 702 The Collecting Process SHOULD accept Data Records without the 703 associated Common Properties required to decode the Data Record. If 704 the Common Properties have not been received at the time Data Records 705 are received, the Collecting Process SHOULD store the Data Records 706 for a short period of time and decode them after the Common 707 Properties definitions are received. The short period of time MUST 708 be lower than the lifetime of definitions associated with identifiers 709 considered unique within the UDP session. 711 6.2. TCP 713 When the TCP connection is reset, either gracefully or abnormally, 714 the Collecting Processes MUST delete all commonPropertiesID values 715 and associated Common Properties data corresponding to that 716 connection. 718 If a Collection Process receives a commonPropertiesID Withdraw 719 message, the Collection Process MUST expire the related Common 720 Properties data. 722 7. Advanced Techniques 724 7.1. Multiple Data Reduction 726 A Flow Record can refer to one or more Common Properties sets; the 727 use of multiple Common Properties can lead to more efficient exports. 728 When sets of Common Properties are identified in the data, it may be 729 found that there is more than one set of non-overlapping properties. 731 Note that in the case of multiple Common Properties in one Data 732 Record, the different sets of Common Properties MUST be disjoint 733 (i.e. MUST NOT have Information Elements in common), to avoid 734 potential collisions. 736 Consider a set of properties "A", e.g. common sourceAddressA and 737 sourcePortA, and another set of properties "B", e.g. 738 destinationAddressB and destinationPortB. Figure 6 shows how this 739 information is repeated with classical IPFIX export in several Flow 740 Records. 742 +--------+--------+---------+---------+---------------------+ 743 |srcAddrA|srcPortA|destAddrB|destPortB| | 744 +--------+--------+---------+---------+---------------------+ 745 |srcAddrA|srcPortA|destAddrC|destPortC| | 746 +--------+--------+---------+---------+---------------------+ 747 |srcAddrD|srcPortD|destAddrB|destPortB| | 748 +--------+--------+---------+---------+---------------------+ 749 |srcAddrD|srcPortD|destAddrC|destPortC| | 750 +--------+--------+---------+---------+---------------------+ 751 | ... | ... | ... | ... | ... | 752 +--------+--------+---------+---------+---------------------+ 754 Figure 6: Common and Specific Properties exported together 756 Besides that other sets of Properties might be repeated as well (e.g. 757 properties C and D in the figure above). 759 We can separate the Common Properties into the properties A composed 760 of sourceAddressA and sourcePortA, properties D composed of 761 sourceAddressD and sourcePortD, and into the properties B composed of 762 destinationAddressB and destinationPortB and properties C composed of 763 destinationAddressC and destinationPortC,. These four records can be 764 expanded to four combinations of Data Records to reduce redundancy 765 without the need to define four complete sets of Common Properties 766 (see the figure below). The more Common Properties sets are defined, 767 the more combinations are available. 769 +-------------------+-----------------+-------------+ 770 | index for prop. A | sourceAddressA | sourcePortA | 771 +-------------------+-----------------+-------------+ 772 | index for prop. D | sourceAddressD | sourcePortD | 773 +-------------------+-----------------+-------------+ 775 +-------------------+---------------------+------------------+ 776 | index for prop. B | destinationAddressB | destinationPortB | 777 +-------------------+---------------------+------------------+ 778 | index for prop. C | destinationAddressC | destinationPortC | 779 +-------------------+---------------------+------------------+ 781 +-----------------+-----------------+-----------------------+ 782 |index for prop. A|index for prop. B| | 783 +-----------------+-----------------+-----------------------+ 784 |index for prop. A|index for prop. C| | 785 +-----------------+-----------------+-----------------------+ 786 |index for prop. D|index for prop. B| | 787 +-----------------+-----------------+-----------------------+ 788 |index for prop. D|index for prop. C| | 789 +-----------------+-----------------+-----------------------+ 791 Multiple Common (above) and Specific Properties (below) exported 792 separately 794 The advantage of the multiple Common Properties is that the objective 795 of reducing the bandwidth is met while the number of indexes is kept 796 to a minimum. Defining an extra index for all records would not 797 bring to save bandwidth in the case of Figure 6 and is generally a 798 less efficient solution. 800 If a set of Flow Records share multiple sets of Common Properties, 801 multiple commonPropertiesID instances MAY be used to increase export 802 efficiency even further, as displayed in Figure 8. 804 +--------------------------- + +---------------------+ 805 | Common Properties | | Specific Properties | Template 806 | Option Template Record | | Template Record | Definition 807 | | | | 808 | Scope: commonPropertiesID1 | | commonPropertiesID1 | 809 | Scope: commonPropertiesID2 | | commonPropertiesID2 | 810 | Common Properties | | Specific Properties | 811 +------------+---------------+ +--------+------------+ 812 .............|...............................|....................... 813 | | 814 +------------v-------------+ +----------v----------+ 815 | Common Properties | | Specific Properties |+ Exported 816 | Data Record |------> Data Records || Data 817 +------------------------- + +---------------------+| Records 818 +---------------------+ 820 Figure 8: Multiple Data Reduction 822 7.2. Cascading Common Properties 824 An Exporting Process MUST NOT export any set of Common Properties 825 which contains, either directly or via other cascaded Common 826 Properties, references to itself in its own definition (i.e., a 827 circular definition). When the Collecting Process receives Common 828 Properties that reference other Common Properties, it MUST resolve 829 the references to Common Properties. If the Common Properties aren't 830 available at the time Data Records are received, the Collecting 831 Process SHOULD store the Data Records for a short period of time and 832 decode them after the Common Properties are received. 834 If the Collecting Process could not decode a cascading Common 835 Properties definition because the referenced Common Properties are 836 not available before the short period of time, then the Collecting 837 Process SHOULD log the error. 839 If the Collecting Process could not decode a cascading Common 840 Properties definition because it detects a circular definition, then 841 the Collecting Process SHOULD log the error. 843 Information Element ordering MUST be preserved when creating and 844 expanding Common Properties. 846 8. Export and Evaluation Considerations 848 The objective of the method specified in this document is the 849 reduction in the amount of measurement data that has to be 850 transferred from the Exporter to the Collector. Note that the 851 efficiency of this method may vary, as discussed in this section. In 852 addition there might be less storage capacity required at the 853 Collector side if the Collector decides to store the Data Records as 854 they arrive, without reconstructing the initial Flow Record. 856 On the other hand, this method requires additional resources on both 857 the Exporter and the Collector. The Exporter has to manage Common 858 Properties information and to assign commonPropertiesId values. The 859 Collector has to process records described by two templates instead 860 of just one. Additional effort is also required when post processing 861 the measurement data, in order to correlate Flow Records with Common 862 Properties information. 864 8.1. Transport Protocol Choice 866 The proposed method is most effective using a reliable transport 867 protocol for the transfer of the Common Properties. Therefore the 868 use of PR-SCTP with the reliable mode or TCP is recommended. 869 However, if the path from the Exporting Process to the Collecting 870 Process is not fully reliable, the SCTP or TCP retransmission might 871 reduce the benefits of this specification. If the path from the 872 Exporting Process to the Collecting Process is full reliable, the use 873 of UDP is less effective because the Common Properties have to be re- 874 sent regularly. 876 8.2. Reduced Size Encoding 878 The transfer of the commonPropertiesIDs originates some overhead and 879 might even increase the amount of exported data if the length of the 880 commonPropertiesID field is not shorter than the length of the 881 replaced fields. 883 In cases where the range of the commonPropertiesID can be restricted, 884 it is RECOMMENDED to apply reduced-size encoding to the 885 commonPropertiesID, to achieve a further bandwidth efficiency gain. 887 8.3. Efficiency Gain 889 While the goal of this specification is to reduce the bandwidth, the 890 efficiency might be limited. Indeed, the efficiency gain is based on 891 the numerous redundant information in Flows and would be directly 892 proportional to the re-use of the defined commonPropertiesID values 893 (In other words, the more we re-use a commonPropertiesID value, the 894 better the efficiency gain), with a theoretical limit where all the 895 Data Records would use a single commonPropertiesID. While the 896 Exporting Process can evaluate the direct gain for the Flow Records 897 to be exported, it cannot predict whether future Flow Records would 898 contain the information specified by active commonPropertiesID 899 values. This implies that the efficiency factor of this 900 specification is higher for specific applications where filtering is 901 involved, such as one-way delay or trajectory sampling. 903 Note that this technique might even lead to an increase in bandwidth 904 usage under certain conditions. Taking into account the overhead of 905 exporting the commonPropertiesID values, if the commonPropertiesID 906 values are not used in future Data Records, this technique would 907 actually increase the export bandwidth. A typical case would be the 908 assignments of Common Properties based on past observed traffic, 909 hoping that future Flows would contain the same characteristics. 911 The efficiency gain depends also on the difference between the length 912 of the replaced fields and the length of the commonPropertiesID. The 913 shorter is the length of commonPropertiesID with respect to the total 914 length of the Common Properties fields, the bigger is the gain. 916 The example in section Appendix A.2 below uses IPFIX to export 917 measurement data for each received packet. In that case, for a Flow 918 of 1000 packets the amount of data can be decreased more than 26 919 percent. 921 9. IANA Considerations 923 This document has no actions for IANA. 925 10. Security Considerations 927 The same security considerations as for the IPFIX Protocol 928 [I-D.ietf-ipfix-protocol] apply. 930 11. Acknowledgments 932 The authors would like to thank Guido Pohl for initiating this work 933 and for his contribution to early versions of this document. Thanks 934 also to Andrew Johnson, Gehrard Muenz, Brian Trammell and Paul Aitken 935 for their comments and feedback. 937 12. References 938 12.1. Normative References 940 [I-D.ietf-ipfix-protocol] 941 Claise, B., "Specification of the IPFIX Protocol for the 942 Exchange", draft-ietf-ipfix-protocol-24 (work in 943 progress), November 2006. 945 [I-D.ietf-ipfix-info] 946 Quittek, J., "Information Model for IP Flow Information 947 Export", draft-ietf-ipfix-info-15 (work in progress), 948 February 2007. 950 [I-D.ietf-psamp-protocol] 951 Claise, B., "Packet Sampling (PSAMP) Protocol 952 Specifications", draft-ietf-psamp-protocol-07 (work in 953 progress), October 2006. 955 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 956 Requirement Levels", BCP 14, RFC 2119, March 1997. 958 12.2. Informative References 960 [I-D.ietf-ipfix-as] 961 Zseby, T., "IPFIX Applicability", draft-ietf-ipfix-as-11 962 (work in progress), February 2007. 964 [I-D.ietf-ipfix-architecture] 965 Sadasivan, G., "Architecture for IP Flow Information 966 Export", draft-ietf-ipfix-architecture-12 (work in 967 progress), September 2006. 969 [I-D.ietf-psamp-info] 970 Dietz, T., "Information Model for Packet Sampling 971 Exports", draft-ietf-psamp-info-05 (work in progress), 972 October 2006. 974 [I-D.ietf-psamp-sample-tech] 975 Zseby, T., "Sampling and Filtering Techniques for IP 976 Packet Selection", draft-ietf-psamp-sample-tech-07 (work 977 in progress), July 2005. 979 [I-D.ietf-psamp-mib] 980 Dietz, T. and B. Claise, "Definitions of Managed Objects 981 for Packet Sampling", draft-ietf-psamp-mib-06 (work in 982 progress), June 2006. 984 [I-D.ietf-psamp-framework] 985 Duffield, N., "A Framework for Packet Selection and 986 Reporting", draft-ietf-psamp-framework-11 (work in 987 progress), May 2007. 989 [RFC2960] Stewart, R., Xie, Q., Morneault, K., Sharp, C., 990 Schwarzbauer, H., Taylor, T., Rytina, I., Kalla, M., 991 Zhang, L., and V. Paxson, "Stream Control Transmission 992 Protocol", RFC 2960, October 2000. 994 [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. 995 Jacobson, "RTP: A Transport Protocol for Real-Time 996 Applications", STD 64, RFC 3550, July 2003. 998 [RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander, 999 "Requirements for IP Flow Information Export (IPFIX)", 1000 RFC 3917, October 2004. 1002 Appendix A. Examples 1004 A.1. Per Flow Data Reduction 1006 In this section we show how Flow information can be exported 1007 efficiently using the method described in this draft. Let's suppose 1008 we have to periodically export data about two IPv6 Flows. 1010 In this example we report the following information: 1012 Flow| dstIPv6Address | dst- |nPkts|nBytes 1013 | | Port | | 1014 ---------------------------------------------------------------- 1015 A |2001:DB8:80AD:5800:0058:0800:2023:1D71 | 80 | 30 | 6000 1016 | | | | 1017 A |2001:DB8:80AD:5800:0058:0800:2023:1D71 | 80 | 50 | 9500 1018 | | | | 1019 B |2001:DB8:80AD:5800:0058:00AA:00B7:AF2B | 1932 | 60 | 8000 1020 | | | | 1021 A |2001:DB8:80AD:5800:0058:0800:2023:1D71 | 80 | 40 | 6500 1022 | | | | 1023 A |2001:DB8:80AD:5800:0058:0800:2023:1D71 | 80 | 60 | 9500 1024 | | | | 1025 B |2001:DB8:80AD:5800:0058:00AA:00B7:AF2B | 1932 | 54 | 7600 1027 The Common Properties in this case are the destination IPv6 address 1028 and the destination port. We first define an Option Template that 1029 contains the following Information Elements: 1031 o Scope: commonPropertiesID in [I-D.ietf-ipfix-info], with a type of 1032 137 and a length of 8 octets. 1034 o The destination IPv6 address: destinationIPv6Address in 1035 [I-D.ietf-ipfix-info], with a type of 28 and a length of 16 1036 octets. 1038 o The destination port: destinationTransportPort in 1039 [I-D.ietf-ipfix-info], with a type of 11, and a length of 2 octets 1041 Figure 10 shows the Option template defining the Common Properties 1042 with commonPropertiesID as scope: 1044 0 1 2 3 1045 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1046 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1047 | Set ID = 3 | Length = 24 octets | 1048 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1049 | Template ID = 257 | Field Count = 3 | 1050 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1051 | Scope Field count = 1 |0| commonPropertiesID = 137 | 1052 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1053 | Scope 1 Field Length = 8 |0| destinationIPv6Address = 28| 1054 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1055 | Field Length = 16 |0|destinationTransportPort = 11| 1056 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1057 | Field Length = 2 | (Padding) | 1058 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1060 Figure 10: Common Properties Option Template 1062 The Specific Properties Template consists of the information not 1063 contained in the Option Templates, i.e. Flow specific information, n 1064 this case the number of packets and the number of bytes to be 1065 reported. Additionally, this Template contains the 1066 commonPropertiesID. In Data Records, the value of this field will 1067 contain one of the unique indices of the Option Records exported 1068 before. It contains the following Information Elements (see also 1069 Figure 11): 1071 o commonPropertiesID with a length of 8 octets 1073 o The number of packets of the Flow: inPacketDeltaCount in 1074 [I-D.ietf-ipfix-info], with a length of 4 octets. 1076 o The number of octets of the Flow: inOctetDeltaCount in 1077 [I-D.ietf-ipfix-info], with a length of 4 octets 1079 0 1 2 3 1080 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1081 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1082 | Set ID = 2 | Length = 20 octets | 1083 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1084 | Template ID = 258 | Field Count = 3 | 1085 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1086 |0| commonPropertiesID = 137 | Field Length = 8 | 1087 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1088 |0| inPacketDeltaCount = 2 | Field Length = 4 | 1089 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1090 |0| inOctetDeltaCount = 1 | Field Length = 4 | 1091 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1093 Figure 11: Specific Properties Template 1095 Considering the data shown at the beginning of this example, the 1096 following two Data Records will be exported: 1098 Common- | dstAddress | dst- 1099 PropertiesID | | Port 1100 -------------+-----------------------------------------+------- 1101 101 | 2001:DB8:80AD:5800:0058:0800:2023:1D71 | 80 1102 | | 1103 102 | 2001:DB8:80AD:5800:0058:00AA:00B7:AF2B | 1932 1105 The Data Records reporting the Common Properties will look like: 1107 0 1 2 3 1108 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1109 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1110 | Set ID = 257 | Length = 60 octets | 1111 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1112 | | 1113 +- 101 -+ 1114 | | 1115 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1116 | | 1117 +- -+ 1118 | | 1119 +- 2001:DB8:80AD:5800:0058:0800:2023:1D71 -+ 1120 | | 1121 +- -+ 1122 | | 1123 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1124 | 80 | | 1125 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- -+ 1126 | 102 | 1127 +- -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1128 | | | 1129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -+ 1130 | | 1131 +- -+ 1132 | 2001:DB8:80AD:5800:0058:00AA:00B7:AF2B | 1133 +- -+ 1134 | | 1135 +- -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1136 | | 1932 | 1137 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1139 Figure 13: Data Records reporting Common Properties 1141 The Data Records will in turn be: 1143 commonPropertiesID | inPacketDeltaCount | inOctetDeltaCount 1144 --------------------------------------------------------------- 1145 101 | 30 | 6000 1146 101 | 50 | 9500 1147 102 | 60 | 8000 1148 101 | 40 | 6500 1149 101 | 60 | 9500 1150 102 | 54 | 7600 1152 Figure 15 shows the first Data Record listed in the table: 1154 0 1 2 3 1155 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1157 | Set ID = 258 | Length = 16 | 1158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1159 | | 1160 +- 101 -+ 1161 | | 1162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1163 | 30 | 6000 | 1164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1166 Figure 15: Data Records reporting Common Properties 1168 A.2. Per Packet Data Reduction 1170 An example of the per packet data reduction is the measurement of 1171 One-Way Delay (OWD), where the exact same specific packet must be 1172 observed at the source and destination of the path to be measured. 1173 By subtracting the time of observation of the same packet at the two 1174 end points with synchronized clocks, the OWD is computed. As the OWD 1175 is measured for a specific application on which a Service Level 1176 Agreement (SLA) is bound, this translates into the observation of 1177 multiple packets with Specific Properties, results of filtering. In 1178 order to match the identical packet at both Observation Points, a 1179 series of packets with a set of properties (For example, all the 1180 packets of a specific source and destination IP addresses, of a 1181 specific DSCP value, and of a specific destination transport port) 1182 must be observed at both ends of the measurements. This implies that 1183 the source and destination must export of a series of Flow Records 1184 composed of two types of information: some common information for all 1185 packets, and some unique information about packets in order to 1186 generate a unique identifier for each packet passing this Observation 1187 Point (for example, a hash value on the invariant fields of the 1188 packet). So, the source and destination composing the measurements 1189 end points can individually and independently apply the redundancy 1190 technique described in this draft in order to save some bandwidth for 1191 their respective Flow Records export. 1193 The Templates required for exporting measurement data of this kind 1194 are illustrated in the figures below. Figure 16 shows the Option 1195 Template containing the information concerning Flows using the 1196 commonPropertiesID as scope. In the Common Properties Template we 1197 export the following Information Elements: 1199 o The source IPv4 Address: sourceIPv4Address in 1200 [I-D.ietf-ipfix-info], with a type of 8 and a length of 4 octets. 1202 o The destination IPv4 Address: destinationIPv4Address in 1203 [I-D.ietf-ipfix-info], with a type of 12 and a length of 4 octets. 1205 o The Class of Service field: ClassOfServiceIPv4 in 1206 [I-D.ietf-ipfix-info], with a type of 5 and a length of 1 octet 1208 o The Protocol Identifier: protocolIdentifier in 1209 [I-D.ietf-ipfix-info], with a type of 4 and a length of 1 octet 1211 o The source port: sourceTransportPort in [I-D.ietf-ipfix-info], 1212 with a type of 7 and a length of 2 octets. 1214 o The destination port: destinationTransportPort in 1215 [I-D.ietf-ipfix-info], with a type of 11 and a length of 2 octets. 1217 The commonPropertiesID Information Element is used as the Scope 1218 Field. 1220 0 1 2 3 1221 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1222 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1223 | Set ID = 3 | Length = 40 octets | 1224 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1225 | Template ID = 256 | Field Count = 7 | 1226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1227 | Scope Field count = 1 |0| commonPropertiesID = 137 | 1228 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1229 | Scope 1 Field Length = 4 |0| sourceIPv4Address = 8 | 1230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1231 | Field Length = 4 |0| destinationIPv4Address = 12 | 1232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1233 | Field Length = 4 |0| classOfServiceIPv4 = 5 | 1234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1235 | Field Length = 1 |0| protocolIdentifier = 4 | 1236 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1237 | Field Length = 1 |0| transportSourcePort = 7 | 1238 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1239 | Field Length = 2 |0|transportDestinationPort = 11| 1240 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1241 | Field Length = 2 | 1242 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1244 Figure 16: Example Flow Properties Template 1246 For passive One Way Delay measurement, the Packet Properties 1247 Template, or Specific Properties Template, consists of at least 1248 Timestamp and Packet ID. Additionally, this template contains a 1249 commonPropertiesId field to associate the packet with a Flow. 1251 Figure 17 displays the template with the packet properties. In this 1252 example we export the following Information Elements: 1254 o commonPropertiesID. In this case reduced size encoding is used, 1255 and the Information Element is declared with a length of 4 octets 1256 instead of 8. 1258 o The packet timestamp: observationTimeMilliseconds in the PSAMP 1259 Information Model [I-D.ietf-psamp-info], with a type of 323 and a 1260 length of 8 octets. 1262 o digestHashValue in the PSAMP Information Model 1263 [I-D.ietf-psamp-info], with a type of 326 and a length of 8 octets 1265 o The packet length: ipTotalLength in the IPFIX Information Model 1266 [I-D.ietf-ipfix-info], with a type of 224 and a length of 8 octets 1268 0 1 2 3 1269 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1271 | Set ID = 2 | Length = 36 octets | 1272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1273 | Template ID = 257 | Field Count = 4 | 1274 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1275 |0| commonPropertiesID = 137 | Field Length = 4 | 1276 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1277 |0| observationTimeMillis.= 323 | Field Length = 8 | 1278 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1279 |0| digestHashValue = 326 | Field Length = 8 | 1280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1281 |0| ipTotalLength = 224 | Field Length = 8 | 1282 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1284 Figure 17: Example Packet Properties Template 1286 At the collection point, packet records from the two measurement 1287 points are gathered and correlated by means of the packet ID. The 1288 resulting delay data records are exported in a similar manner as the 1289 packet data. One-way delay data is associated with Flow information 1290 by the commonPropertiesId field. The OWD properties contain the 1291 Packet Pair ID (which is the packet ID of the two contributing packet 1292 records), the timestamp of the packet passing the reference monitor 1293 point in order to reconstruct a time series, the calculated delay 1294 value, and the commonPropertiesID. 1296 In this example using IPFIX to export the measurement data for each 1297 received packet 38 bytes have to be transferred (sourceAddressV4=4, 1298 destinationAddressV4=4, classOfServiceV4=1, protocolIdentifier=1, 1299 sourceTransportPort=2, destionationTransportPort=2, 1300 observationTimeMilliseconds=8, digestHashValue=8, ipTotalLength=8). 1301 Without considering the IPFIX protocol overhead a Flow of 1000 1302 packets produces 38000 bytes of measurement data. Using the proposed 1303 optimization each packet produces an export of only 28 bytes 1304 (observationTimeMilliseconds=8, digestHashValue=8, ipTotalLength=8, 1305 commonPropertiesID=4). The export of the Flow information produces 1306 18 bytes (sourceAddressV4=4, destinationAddressV4=4, 1307 classOfServiceV4=1, protocolIdentifier=1, sourceTransportPort=2, 1308 destionationTransportPort=2, commonPropertiesID=4). For a Flow of 1309 1000 packets this sums up to 28018 bytes. This is a decrease of more 1310 than 26 percent. 1312 A.3. commonPropertiesID Template Withdrawal Message 1314 This section shows an example commonPropertiesID Withdrawal message. 1315 Figure 18 depicts the Option Template Record with the 1316 commonPropertiesID as unique scope field, and no non-scope fields. 1318 0 1 2 3 1319 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1321 | Set ID = 3 | Length = 14 octets | 1322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1323 | Template ID 259 | Field Count = 1 | 1324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1325 | Scope Field count = 1 |0| commonPropertiesID 137 | 1326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1327 | Scope 1 Field Length = 8 | 1328 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1330 Figure 18: example commonPropertiesID withdrawal template 1332 Figure 19 shows the Option Data Record withdrawing commonPropertiesID 1333 N: 1335 0 1 2 3 1336 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1337 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1338 | Set ID = 259 | Length = 12 octets | 1339 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1340 | | 1341 +- N -+ 1342 | | 1343 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1345 Figure 19: commonPropertiesID withdrawal record, withdrawing 1346 commonPropertiesID N 1348 Authors' Addresses 1350 Elisa Boschi 1351 Hitachi Europe SAS 1352 Immeuble Le Theleme 1353 1503 Route les Dolines 1354 06560 Valbonne 1355 France 1357 Phone: +33 4 89874100 1358 Email: elisa.boschi@hitachi-eu.com 1360 Lutz Mark 1361 Fraunhofer FOKUS 1362 Kaiserin Augusta Allee 31 1363 10589 Berlin 1364 Germany 1366 Phone: +49 30 34637306 1367 Email: mark@fokus.fraunhofer.de 1369 Benoit Claise 1370 Cisco Systems 1371 De Kleetlaan 6a b1 1372 Diegem 1813 1373 Belgium 1375 Phone: +32 2 704 5622 1376 Email: bclaise@cisco.com 1378 Full Copyright Statement 1380 Copyright (C) The IETF Trust (2007). 1382 This document is subject to the rights, licenses and restrictions 1383 contained in BCP 78, and except as set forth therein, the authors 1384 retain all their rights. 1386 This document and the information contained herein are provided on an 1387 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1388 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 1389 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 1390 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 1391 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1392 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1394 Intellectual Property 1396 The IETF takes no position regarding the validity or scope of any 1397 Intellectual Property Rights or other rights that might be claimed to 1398 pertain to the implementation or use of the technology described in 1399 this document or the extent to which any license under such rights 1400 might or might not be available; nor does it represent that it has 1401 made any independent effort to identify any such rights. 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