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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group S. Perreault 3 Internet-Draft Jive Communications 4 Intended status: Standards Track T. Tsou 5 Expires: August 21, 2015 Huawei Technologies 6 S. Sivakumar 7 Cisco Systems 8 T. Taylor 9 PT Taylor Consulting 10 February 17, 2015 12 Definitions of Managed Objects for Network Address Translators (NAT) 13 draft-perrault-behave-natv2-mib-01 15 Abstract 17 This memo defines a portion of the Management Information Base (MIB) 18 for devices implementing the Network Address Translator (NAT) 19 function. The new MIB module defined in this document, NATV2-MIB, is 20 intended to replace module NAT-MIB (RFC 4008). NATV2-MIB is not 21 backwards compatible with NAT-MIB, for reasons given in the text of 22 this document. A companion document deprecates all objects in NAT- 23 MIB. NATV2-MIB can be used for monitoring of NAT instances on a 24 device capable of NAT function. Compliance levels are defined for 25 three application scenarios: basic NAT, pooled NAT, and carrier-grade 26 NAT (CGN). 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on August 21, 2015. 45 Copyright Notice 47 Copyright (c) 2015 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. The SNMP Management Framework . . . . . . . . . . . . . . . . 3 63 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 64 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5 65 3.1. Content Provided by the NATV2-MIB Module . . . . . . . . 5 66 3.1.1. Configuration Data . . . . . . . . . . . . . . . . . 5 67 3.1.2. Notifications . . . . . . . . . . . . . . . . . . . . 6 68 3.1.3. State Information . . . . . . . . . . . . . . . . . . 9 69 3.1.4. Statistics . . . . . . . . . . . . . . . . . . . . . 9 70 3.2. Outline of MIB Module Organization . . . . . . . . . . . 11 71 3.3. Detailed MIB Module Walk-Through . . . . . . . . . . . . 13 72 3.3.1. Textual Conventions . . . . . . . . . . . . . . . . . 13 73 3.3.2. Notifications . . . . . . . . . . . . . . . . . . . . 13 74 3.3.3. The Subscriber Table: natv2SubscriberTable . . . . . 13 75 3.3.4. The Instance Table: natv2InstanceTable . . . . . . . 14 76 3.3.5. The Protocol Table: natv2ProtocolTable . . . . . . . 15 77 3.3.6. The Address Pool Table: natv2PoolTable . . . . . . . 15 78 3.3.7. The Address Pool Address Range Table: 79 natv2PoolRangeTable . . . . . . . . . . . . . . . . . 16 80 3.3.8. The Address Map Table: natv2AddressMapTable . . . . . 16 81 3.3.9. The Port Map Table: natv2PortMapTable . . . . . . . . 17 82 3.4. Conformance: Three Application Scenarios . . . . . . . . 17 83 4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 18 84 5. Operational and Management Considerations . . . . . . . . . . 74 85 5.1. Configuration Requirements . . . . . . . . . . . . . . . 74 86 5.2. Transition From and Coexistence With NAT-MIB [RFC 4008] 76 87 6. Security Considerations . . . . . . . . . . . . . . . . . . . 78 88 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 81 89 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 81 90 8.1. Normative References . . . . . . . . . . . . . . . . . . 81 91 8.2. Informative References . . . . . . . . . . . . . . . . . 82 92 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 83 94 1. The SNMP Management Framework 96 For a detailed overview of the documents that describe the current 97 Internet-Standard Management Framework, please refer to section 7 of 98 RFC 3410 [RFC3410]. 100 Managed objects are accessed via a virtual information store, termed 101 the Management Information Base or MIB. MIB objects are generally 102 accessed through the Simple Network Management Protocol (SNMP). 103 Objects in the MIB are defined using the mechanisms defined in the 104 Structure of Management Information (SMI). This memo specifies a MIB 105 module that is compliant to the SMIv2, which is described in STD 58, 106 [RFC2578], [RFC2579] and [RFC2580]. 108 2. Introduction 110 Note to RFC Ed.: please replace RFC yyyy with actual RFC number 111 throughout this document and remove this note. 113 This memo defines a portion of the Management Information Base (MIB) 114 for devices implementing NAT functions. This MIB module, NATV2-MIB, 115 may be used for monitoring of such devices. NATV2-MIB supersedes 116 NAT-MIB [RFC4008], which did not fit well with existing NAT 117 implementations, and hence was not itself much implemented. 118 [I-D.perrault-behave-deprecate-nat-mib-v1] provides a detailed 119 analysis of the deficiencies of NAT-MIB. 121 Relative to [RFC4008] and based on the analysis just mentioned, the 122 present document introduces the following changes: 124 o removed all writable configuration except that related to control 125 of the generation of notifications and the setting of quotas on 126 the use of NAT resources; 128 o minimized the read-only exposure of configuration to what is 129 needed to provide context for the state and statistical 130 information presented by the MIB module; 132 o removed the association between mapping and interfaces, retaining 133 only the mapping aspect; 135 o replaced references to NAT types with references to NAT behaviors 136 as specified in [RFC4787]; 138 o replaced a module-specific enumeration of protocols with the 139 standard protocol numbers provided by the IANA Assigned Internet 140 Protocol Numbers registry. 142 This MIB module adds the following features not present in [RFC4008]: 144 o additional writable protective limits on NAT state data; 146 o additional objects to report state, statistics, and notifications; 148 o support for the carrier grade NAT (CGN) application, including 149 subscriber-awareness, support for an arbitrary number of address 150 realms, and support for multiple NAT instances running on a single 151 device; 153 o expanded support for address pools; 155 o revised indexing of port map entries to simplify traceback from 156 externally observable packet parameters to the corresponding 157 internal endpoint. 159 These features are described in more detail below. 161 The remainder of this document is organized as follows: 163 o Section 3 provides a verbal description of the content and 164 organization of the MIB module. 166 o Section 4 provides the MIB module definition. 168 o Section 5 discusses operational and management issues relating to 169 the deployment of NATV2-MIB. One of these issues is NAT 170 management when both NAT-MIB [RFC4008] and NATV2-MIB are deployed. 172 o Section 6 and Section 7 provide a security discussion and a 173 request to IANA for allocation of an object identifier for the 174 module in the mib-2 tree, respectively. 176 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 177 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 178 "OPTIONAL" in this document are to be interpreted as described in 179 [RFC2119]. 181 This document uses the following terminology: 183 Upper layer protocol: The protocol following the outer IP header of 184 a packet. This follows the terminology of [RFC2460], but as that 185 document points out, "upper" is not necessarily a correct 186 description of the protocol relationships (e.g., where IP is 187 encapsulated in IP). The abbreviated term "protocol" will often 188 be used where it is unambiguous. 190 Trigger: With respect to notifications, the logical recognition of 191 the event that the notification is intended to report. 193 Report: The actual production of a notification message. Reporting 194 can happen later than triggering, or may never happen for a given 195 notification instance, because of the operation of notification 196 rate controls. 198 Address realm: A network domain in which the network addresses are 199 uniquely assigned to entities such that datagrams can be routed to 200 them. (Definition taken from [RFC2663] Section 2.1.) The 201 abbreviated term "realm" will often be used. 203 3. Overview 205 This section provides a prose description of the contents and 206 organization of the NATV2-MIB module. 208 3.1. Content Provided by the NATV2-MIB Module 210 The content provided by the NATV2-MIB module can be classed under 211 four headings: configuration data, notifications, state information, 212 and statistics. 214 3.1.1. Configuration Data 216 As mentioned above, the intent in designing the NATV2-MIB module was 217 to minimize the amount of configuration data presented to that needed 218 to give a context for interpreting the other types of information 219 provided. Detailed descriptions of the configuration data are 220 included with the descriptions of the individual tables. In general, 221 that data is limited to what is needed for indexing and cross- 222 referencing between tables. The two exceptions are the objects 223 describing NAT instance behavior in the NAT instance table, and the 224 detailed enumeration of resources allocated to each address pool in 225 the pool table and its extension. 227 The NATV2-MIB module provides three sets of read-write objects, 228 specifically related to other aspects of the module content. The 229 first set controls the rate at which specific notifications are 230 generated. The second set provides thresholds used to trigger the 231 notifications. These objects are listed in Section 3.1.2. 233 A third set of read-write objects sets limits on resource consumption 234 per NAT instance and per subscriber. When these limits are reached, 235 packets requiring further consumption of the given resource are 236 dropped rather than translated. Statistics described in 237 Section 3.1.4 record the numbers of packets so dropped. Limits are 238 provided for: 240 o total number of address map entries over the NAT instance. Limit 241 is set by object natv2InstanceLimitAddressMapEntries in table 242 natv2InstanceTable. Dropped packets are counted in 243 natv2InstanceAddressMapEntryLimitDrops in that table. 245 o total number of port map entries over the NAT instance. Limit is 246 set by object natv2InstanceLimitPortMapEntries in table 247 natv2InstanceTable. Dropped packets are counted in 248 natv2InstancePortMapEntryLimitDrops in that table. 250 o total number of held fragments (applicable only when the NAT 251 instance can receive fragments out of order; see [RFC4787] 252 Section 11). Limit is set by object 253 natv2InstanceLimitPendingFragments in table natv2InstanceTable. 254 Dropped packets are counted by natv2InstanceFragmentDrops in the 255 same table. 257 o total number of active subscribers (i.e., subscribers having at 258 least one mapping table entry) over the NAT instance. Limit is 259 set by object natv2InstanceLimitSubscriberActives in table 260 natv2InstanceTable. Dropped packets are counted by 261 natv2InstanceSubscriberActiveLimitDrops in the same table. 263 o number of port map entries for an individual subscriber. Limit is 264 set by object natv2SubscriberLimitPortMapEntries in table 265 natv2SubscriberTable. Dropped packets are counted by 266 natv2SubscriberPortMapFailureDrops in the same table. Note that, 267 unlike in the instance table, the per-subscriber count is lumped 268 in with the count of packets dropped because of failures to 269 allocate a port map entry for other reasons to save on storage. 271 3.1.2. Notifications 273 NATV2-MIB provides five notifications, intended to provide warning of 274 the need to provision or reallocate NAT resources. As indicated in 275 the previous section, each notification is associated with two read- 276 write objects: a control on the rate at which that notification is 277 generated, and a threshold value used to trigger the notification in 278 the first place. The default setting within the MIB module 279 specification is that all notifications are disabled. The setting of 280 threshold values is discussed in Section 5. 282 The five notifications are as follows: 284 o Two notifications relate to the management of address pools. One 285 indicates that usage equals or exceeds an upper threshold, and is 286 therefore a warning that the pool may be over-utilized unless more 287 addresses are assigned to it. The other notification indicates 288 that usage equals or has fallen below a lower threshold, 289 suggesting that some addresses allocated to that pool could be 290 reallocated to other pools. Address pool usage is calculated as 291 the percentage of the total number of ports allocated to the 292 address pool that are already in use, for the most-mapped protocol 293 at the time the notification is generated. The notifications 294 identify that protocol and report the number of port map entries 295 for that protocol in the given address pool at the moment the 296 notification was triggered. 298 o Two notifications relate to the number of address and port map 299 entries respectively, in total over the whole NAT instance. In 300 both cases the threshold that triggers the notification is an 301 upper threshold. The notifications return the number of mapping 302 entries of the given type, plus a cumulative counter of the number 303 of entries created in that mapping table at the moment the 304 notification was triggered. The intent is that the notifications 305 provide a warning that the total number of address or port map 306 entries is approaching the configured limit. 308 o The final notification is generated on a per-subscriber basis when 309 the number of port map entries for that subscriber crosses the 310 associated threshold. The objects returned by this notification 311 are similar to those returned for the instance-level mapping 312 notifications. This notification is a warning that the number of 313 port map entries for the subscriber is approaching the configured 314 limit for that subscriber. 316 Here is a detailed specification of the notifications. A given 317 notification can be disabled by setting the threshold to 0 (default), 318 with the exception noted below. 320 Notification: natv2NotificationPoolUsageLow. Indicates that address 321 pool usage for the most-mapped protocol equals or is less than the 322 threshold value. 324 Compared value: natv2PoolNotifiedPortMapEntries as a percentage of 325 total available ports in the pool. 327 Threshold: natv2PoolThresholdUsageLow in natv2PoolTable. To allow 328 for a threshold of zero usage, disabling of the 329 natv2NotificationPoolUsageLow is done by setting 330 natv2PoolThresholdUsageLow to -1 rather than 0, in contrast to all 331 of the other notifications. 333 Objects returned: natv2PoolNotifiedPortMapEntries and 334 natv2PoolNotifiedPortMapProtocol in natv2PoolTable; 336 Rate control: natv2PoolNotificationInterval in 337 natv2PoolTable (default 20 seconds between notifications for a 338 given address pool). 340 Notification: natv2NotificationPoolUsageHigh. Indicates that address 341 pool usage for the most-mapped protocol has risen to the threshold 342 value or more. 344 Compared value: natv2PoolNotifiedPortMapEntries as a percentage of 345 total available ports in the pool. 347 Threshold: natv2PoolThresholdUsageHigh in natv2PoolTable; 349 Objects returned: natv2PoolNotifiedPortMapEntries, 350 natv2PoolNotifiedPortMapProtocol in natv2PoolTable; 352 Rate control: natv2PoolNotificationInterval in 353 natv2PoolTable (default 20 seconds between notifications for a 354 given address pool). 356 Notification: natv2NotificationInstanceAddressMapEntriesHigh. 357 Indicates that the total number of entries in the address map table 358 over the whole NAT instance equals or exceeds the threshold value. 360 Compared value: natv2InstanceAddressMapEntries in 361 natv2InstanceTable; 363 Threshold: natv2InstanceThresholdAddressMapEntriesHigh in 364 natv2InstanceTable; 366 Objects returned: natv2InstanceAddressMapEntries, 367 natv2InstanceAddressMapCreations in natv2InstanceTable; 369 Rate control: natv2InstanceNotificationInterval in 370 natv2InstanceTable (default 10 seconds between notifications for a 371 given NAT instance). 373 Notification: natv2NotificationInstancePortMapEntriesHigh. Indicates 374 that the total number of entries in the port map table over the whole 375 NAT instance equals or exceeds the threshold value. 377 Compared value: natv2InstancePortMapEntries in natv2InstanceTable; 379 Threshold: natv2InstanceThresholdPortMapEntriesHigh in 380 natv2InstanceTable; 382 Objects returned: natv2InstancePortMapEntries, 383 natv2InstancePortMapCreations in natv2InstanceTable; 385 Rate control: natv2InstanceNotificationInterval in 386 natv2InstanceTable (default 10 seconds between notifications for a 387 given NAT instance). 389 Notification: natv2NotificationSubscriberPortMapEntriesHigh. 390 Indicates that the total number of entries in the port map table for 391 the given subscriber equals or exceeds the threshold value configured 392 for that subscriber. 394 Compared value: natv2SubscriberPortMapEntries in 395 natv2SubscriberTable; 397 Threshold: natv2SubscriberThresholdPortMapEntriesHigh in 398 natv2SubscriberTable; 400 Objects returned: natv2SubscriberPortMapEntries, 401 natv2SubscriberPortMapCreations in natv2SubscriberTable; 403 Rate control: natv2SubscriberNotificationInterval in 404 natv2SubscriberTable (default 60 seconds between notifications for 405 a given subscriber). 407 3.1.3. State Information 409 State information provides a snapshot of the content and extent of 410 the NAT mapping tables at a given moment of time. The address and 411 port mapping tables are described in detail below. In addition to 412 these tables, two state variables are provided: current number of 413 entries in the address mapping table, and current number of entries 414 in the port mapping table. With one exception, these are provided at 415 four levels of granularity: per NAT instance, per protocol, per 416 address pool, and per subscriber. Address map entries are not 417 tracked per protocol, since address mapping is protocol-independent. 419 3.1.4. Statistics 421 NATV2-MIB provides a number of counters, intended to help both with 422 provisioning of the NAT and debugging of problems. As with the state 423 data, these counters are provided at the four levels of NAT instance, 424 protocol, address pool, and subscriber when they make sense. Each 425 counter is cumulative beginning from a "last discontuity time" 426 recorded by an object that is usually in the table containing the 427 counter. 429 The basic set of counters, as reflected in the NAT instance table, is 430 as follows: 432 Translations: number of packets processed and translated (in this 433 case, in total for the NAT instance); 435 Address map entry creations: cumulative number of address map 436 entries created, including static mappings; 438 Port map entry creations: cumulative number of port map entries 439 created, including static mappings; 441 Address map limit drops: cumulative number of packets dropped rather 442 than translated because the packet would have triggered the 443 creation of a new address mapping, but the configured limit on 444 number of address map entries has already been reached. 446 Port map limit drops: cumulative number of packets dropped rather 447 than translated because the packet would have triggered the 448 creation of a new port mapping, but the configured limit on number 449 of port map entries has already been reached. 451 Active subscriber limit drops: cumulative number of packets dropped 452 rather than translated because the packet would have triggered the 453 creation of a new address and/or port mapping for a subscriber 454 with no existing entries in either table, but the configured limit 455 on number of active subscribers has already been reached. 457 Address mapping failure drops: cumulative number of packets dropped 458 because the packet would have triggered the creation of a new 459 address mapping, but no address could be allocated in the external 460 realm concerned because all addresses from the selected address 461 pool (or the whole realm, if no address pool has been configured 462 for that realm) have already been fully allocated. 464 Port mapping failure drops: cumulative number of packets dropped 465 because the packet would have triggered the creation of a new port 466 mapping, but no port could be allocated for the protocol 467 concerned. The precise conditions under which these packet drops 468 occur depend on the pooling behavior [RFC4787] configured or 469 implemented in the NAT instance. See the DESCRIPTION clause for 470 the natv2InstancePortMapFailureDrops object for a detailed 471 description of the different cases. These cases were defined with 472 care to ensure that address mapping failure could be distinguished 473 from port mapping failure. 475 Fragment drops: cumulative number of packets dropped because the 476 packet contains a fragment and the fragment behavior [RFC4787] 477 configured or implemented in the NAT instance indicates that the 478 packet should be dropped. The main case is a NAT instance that 479 meets REQ-14 of [RFC4787], hence can receive and process out-of- 480 order fragments. In that case, dropping occurs only when the 481 configured limit on pending fragments provided by NATV2-MIB has 482 already been reached. The other cases are detailed in the 483 DESCRIPTION clause of the natv2InstanceFragmentBehavior object. 485 Other resource drops: cumulative number of packets dropped because 486 of unavailability of some other resource. The most likely case 487 would be packets where the upper layer protocol is not one 488 supported by the NAT instance. 490 Table 1 indicates the granularities at which these statistics are 491 reported. 493 +-----------------------+------------+----------+------+------------+ 494 | Statistic | NAT | Protocol | Pool | Subscriber | 495 | | Instance | | | | 496 +-----------------------+------------+----------+------+------------+ 497 | Translations | Yes | Yes | No | Yes | 498 | Address map entry | Yes | No | Yes | Yes | 499 | creations | | | | | 500 | Port map entry | Yes | Yes | Yes | Yes | 501 | creations | | | | | 502 | Address map limit | Yes | No | No | No | 503 | drops | | | | | 504 | Port map limit drops | Yes | No | No | Yes | 505 | Active subscriber | Yes | No | No | No | 506 | limit drops | | | | | 507 | Address mapping | Yes | No | Yes | Yes | 508 | failure drops | | | | | 509 | Port mapping failure | Yes | Yes | Yes | Yes | 510 | drops | | | | | 511 | Fragment drops | Yes | No | No | No | 512 | Other resource drops | Yes | No | No | No | 513 +-----------------------+------------+----------+------+------------+ 515 Table 1: Statistics Provided By Level of Granularity 517 3.2. Outline of MIB Module Organization 519 Figure 1 shows how object identifiers are organized in the NATV2-MIB 520 module. Under the general natv2MIB object identifier in the mib-2 521 tree, the objects are classed into four groups: 523 natv2MIBNotifications(0) identifies the five notifications described 524 in Section 3.1.2; 526 natv2MIBDeviceObjects(1) identifies objects relating to the whole 527 device, specifically, the subscriber table. 529 natv2MIBInstanceObjects(2) identifies objects relating to individual 530 NAT instances. These include the NAT instance table, the protocol 531 table, the address pool table and its address range expansion, the 532 address map table, and the port map table. 534 natv2MIBConformance(3) identifies the group and compliance clauses, 535 specified for the three application scenarios described in 536 Section 3.4. 538 natv2MIB 539 | 540 +-------------+-------------+-------------+ 541 | | | | 542 | | | 543 0 | | | 544 natv2MIBNotifications | | | 545 | | | 546 | 1 | | 547 | natv2MIBDeviceObjects | | 548 Five | | 549 notifications | 2 | 550 | natv2MIBInstanceObjects | 551 | | 552 Subscriber | 3 553 table | natv2MIBConformance 554 | | 555 | | 556 Six per-NAT- | 557 instance tables | 558 | 559 +----------------------+------- 560 | | 561 | | 563 1 2 564 natv2MIBCompliances natv2MIBGroups 565 | | 566 | | 567 Basic Basic 568 Pooled Pooled 569 Carrier grade NAT Carrier grade NAT 571 Figure 1: Organization of Object Identifiers For NATV2-MIB 573 3.3. Detailed MIB Module Walk-Through 575 This section reviews the contents of the NATV2-MIB module. The table 576 descriptions include references to subsections of Section 3.1 where 577 desirable to avoid repetition of that information. 579 3.3.1. Textual Conventions 581 The module defines four key textual conventions: ProtocolNumber, 582 Natv2SubscriberIndex, Natv2InstanceIndex, and Natv2PoolIndex. 583 ProtocolNumber is based on the IANA registry of protocol numbers, 584 hence is potentially reusable by other MIB modules. 586 Objects of type Natv2SubscriberIndex identify individual subscribers 587 served by the the NAT device. The values of these identifiers are 588 administered and, in intent, are permanently associated with their 589 respective subscribers. Reuse of a value after a subscriber has been 590 deleted is discouraged. The scope of the subscriber index was 591 defined to be at device rather than NAT instance level to make it 592 easier to shift subscribers between instances (e.g., for load 593 balancing). 595 Objects of type Natv2InstanceIndex identify specific NAT instances on 596 the device. Again, these are administered values intended to be 597 permanently associated with the NAT instances to which they have been 598 assigned. 600 Objects of type Natv2PoolIndex identify individual address pools in a 601 given NAT instance. As with the subscriber and instance index 602 objects, the pool identifiers are administered and intended to be 603 permanently associated with their respective pools. 605 3.3.2. Notifications 607 Notifications were described in Section 3.1.2. 609 3.3.3. The Subscriber Table: natv2SubscriberTable 611 Table natv2SubscriberTable is indexed by subscriber index. One 612 conceptual row contains information relating to a specific 613 subscriber: the subscriber's internal address or prefix for 614 correlation with other management information; state and statistical 615 information as described in Section 3.1.3 and Section 3.1.4, the per- 616 subscriber control objects described in Section 3.1.1, and 617 natv2SubscriberDiscontinuityTime, which provides a timestamp of the 618 latest time following which the statistics have accumulated without 619 discontinuity. 621 Turning back to the address information for a moment: this 622 information includes the identity of the address realm in which the 623 address is routable. That enables support of an arbitrary number of 624 address realms on the same NAT instance. Address realm identifiers 625 are administered values in the form of a limited-length 626 SnmpAdminString. In the absence of configuration to the contrary, 627 the default realm for all internal addresses as recorded in mapping 628 entries is "internal". 630 The term "address realm" is defined in [RFC2663] Section 2.1 and 631 reused in subsequent NAT-related documents. 633 In the special case of DS-Lite [RFC6333], for unique matching of the 634 subscriber data to other information in the MIB module, it is 635 necessary that the address information should relate to the outer 636 IPv6 header of packets going to or from the host, with the address 637 realm being the one in which that IPv6 address is routable. The 638 presentation of address information for other types of tunneled 639 access to the NAT is out of scope. 641 3.3.4. The Instance Table: natv2InstanceTable 643 Table natv2InstanceTable is indexed by an object of type 644 Natv2InstanceIndex. A conceptual row of this table provides 645 information relating to a particular NAT instance configured on the 646 device. 648 Configuration information provided by this table includes an instance 649 name of type DisplayString that may have been configured for this 650 instance, and a set of objects indicating respectively the port 651 mapping, filtering, pooling, and fragment behaviors configured or 652 implemented in the instance. These behaviors are all defined in 653 [RFC4787]. Their values affect the interpretation of some of the 654 statistics provided in the instance table. 656 Read-write objects listed in Section 3.1.2 set the notification rate 657 for instance-level notifications and set the thresholds that trigger 658 them. Additional read-write objects described in Section 3.1.1 set 659 limits on the number of address and port mapping entries, number of 660 pending fragments, and number of active subscribers for the instance. 662 The state and statistical information provided by this table consists 663 of the per-instance items described in Section 3.1.3 and 664 Section 3.1.4 respectively. natv2InstanceDiscontinuityTime is a 665 timestamp giving the time beyond which all of the statistical 666 counters in natv2InstanceTable are guaranteed to have accumulated 667 continuously. 669 3.3.5. The Protocol Table: natv2ProtocolTable 671 The protocol table is indexed by the NAT instance number and an 672 object of type ProtocolNumber as described in Section 3.3.1 (i.e., an 673 IANA-registered protocol number). The set of protocols supported by 674 the NAT instance is implementation-dependent, but MUST include 675 ICMP(1), TCP(6), UDP(17), and ICMPv6(58). Depending on the 676 application, it SHOULD include IPv4 encapsulation(4), IPv6 677 encapsulation(41), IPSec AH(51), and SCTP(132). Support of PIM(103) 678 is highly desirable. 680 This table includes no configuration information. The state and 681 statistical information provided by this table consists of the per- 682 protocol items described in Section 3.1.3 and Section 3.1.4 683 respectively. natv2InstanceDiscontinuityTime in natv2InstanceTable is 684 reused as the timestamp giving the time beyond which all of the 685 statistical counters in natv2ProtocolTable are guaranteed to have 686 accumulated continuously. The reasoning is that any event affecting 687 the continuity of per-protocol statistics will affect the continuity 688 of NAT instance statistics, and vice versa. 690 3.3.6. The Address Pool Table: natv2PoolTable 692 The address pool table is indexed by the NAT instance identifier for 693 the instance on which it is provisioned, plus a pool index of type 694 Natv2PoolIndex. Configuration information provided includes the 695 address realm for which the pool provides addresses, the type of 696 address (IPv4 or IPv6) supported by the realm, plus the port range it 697 makes available for allocation. The same set of port numbers (or, in 698 the ICMP case, identifier values), is made available for every 699 protocol supported by the NAT instance. The port range is specified 700 in terms of minimum and maximum port number. 702 The state and statistical information provided by this table consists 703 of the per-pool items described in Section 3.1.3 and Section 3.1.4 704 respectively, plus two additional state objects described below. 705 natv2PoolTable provides the pool-specific object 706 natv2PoolDiscontinuityTime to indicate the time since which the 707 statistical counters have accumulated continuously. 709 Read-write objects to set high and low thresholds for pool usage 710 notifications and for governing notification rate were identified in 711 Section 3.1.2. The default interval between notifications for a 712 given address pool is set to 20 seconds. 714 Implementation note: the thresholds are defined in terms of 715 percentage of available port utilization. The number of available 716 ports in a pool is equal to (max port - min port + 1) (from the 717 natv2PoolTable configuration information) multiplied by the number 718 of addresses provisioned in the pool (sum of number of addresses 719 provided by each natv2PoolRangeTable conceptual row relating to 720 that pool). At configuration time, the thresholds can be 721 recalculated in terms of total number of port map entries 722 corresponding to the configured percentage, so that runtime 723 comparisons to the current number of port map entries require no 724 further arithmetic operations. 726 natv2PoolTable also provides two state objects that are returned with 727 the notifications. natv2PoolNotifiedPortMapProtocol identifies the 728 most-mapped protocol at the time the notification was triggered. 729 natv2PoolNotifiedPortMapEntries provides the total number of port map 730 entries for that protocol using addresses owned by this pool at that 731 same time. 733 3.3.7. The Address Pool Address Range Table: natv2PoolRangeTable 735 natv2PoolRangeTable provides configuration information only. It is 736 an expansion of natv2PoolTable giving the address ranges with which a 737 given address pool has been configured. As such, it is indexed by 738 the combination of NAT instance index, address pool index, and a 739 conceptual row index, where each conceptual row conveys a different 740 address range. The address range is specified in terms of lowest 741 address, highest address rather than the usual prefix notation to 742 provide maximum flexibility. 744 3.3.8. The Address Map Table: natv2AddressMapTable 746 The address map table provides a table of mappings from internal to 747 external address at a given moment. It is indexed by the combination 748 of NAT instance index, internal realm, internal address type (IPv4 or 749 IPv6) in that realm, the internal address of the local host for which 750 the map entry was created, and a conceptual row index to traverse all 751 of the entries relating to the same internal address. 753 In the special case of DS-Lite [RFC6333], the internal address and 754 realm used in the index are those of the IPv6 outer header. The IPv4 755 source address for the inner header, for which [RFC6333] has reserved 756 addresses in the 192.0.0.0/29 range, is captured in two additional 757 objects in the corresponding conceptual row: 758 natv2AddressMapInternalMappedAddressType, and 759 natv2AddressMapInternalMappedAddress. In cases other than DS-Lite 760 access these objects have no meaning. (Other tunneled access is out 761 of scope.) 763 The additional information provided by natv2AddressMapTable consists 764 of the external realm, address type in that realm, and mapped 765 external address. Depending on implementation support, the table 766 also provides the index of the address pool from which the external 767 address was drawn and the index of the subscriber to which the map 768 entry belongs. 770 3.3.9. The Port Map Table: natv2PortMapTable 772 The port map table provides a table of mappings by protocol from 773 external port, address, and realm to internal port, address, and 774 realm. As such, it is indexed by the combination of NAT instance 775 index, protocol number, external realm identifier, address type in 776 that realm, external address, and external port. The mapping from 777 external realm, address, and port to internal realm, address, and 778 port is unique, so no conceptual row index is needed. The indexing 779 is designed to make it easy to trace individual sessions back to the 780 host, based on the contents of packets observed in the external 781 realm. 783 Beyond the indexing, the information provided by the port map table 784 consists of the internal realm, address type, address, and port 785 number, and, depending on implementation support, the index of the 786 subscriber to which the map entry belongs. 788 As with the address map table, special provision is made for the case 789 of DS-Lite [RFC6333]. The realm and outgoing source address are 790 those for the outer header, and the address type is IPv6. Additional 791 objects natv2PortMapInternalMappedAddressType and 792 natv2PortMapInternalMappedAddress capture the outgoing source address 793 in the inner header, which will be in the well-known 192.0.0.0/29 794 range. 796 3.4. Conformance: Three Application Scenarios 798 The conformance statements in NATV2-MIB provide for three application 799 scenarios: basic NAT, NAT supporting address pools, and carrier grade 800 NAT (CGN). 802 A basic NAT MAY limit the number of NAT instances it supports to one, 803 but MUST support indexing by NAT instance. Similarly, a basic NAT 804 MAY limit the number of realms it supports to two. By definition, a 805 basic NAT is not required to support the subscriber table, the 806 address pool table, or the address pool address range table. Some 807 individual objects in other tables are also not relevant to basic 808 NAT. 810 A NAT supporting address pools adds the address pool table and the 811 address pool address range table to what it implements. Some 812 individual objects in other tables also need to be implemented. A 813 NAT supporting address pools MUST support more than two realms. 815 Finally, a CGN MUST support the full contents of the MIB module. 816 That includes the subscriber table, but also includes the special 817 provision for DS-Lite access in the address and port map tables. 819 4. Definitions 821 This MIB module IMPORTs objects from [RFC2578], [RFC2579], [RFC2580], 822 [RFC3411], and [RFC4001]. 824 NATV2-MIB DEFINITIONS ::= BEGIN 826 IMPORTS 827 MODULE-IDENTITY, 828 OBJECT-TYPE, 829 Integer32, 830 Unsigned32, 831 Counter64, 832 mib-2, 833 NOTIFICATION-TYPE 834 FROM SNMPv2-SMI -- RFC 2578 835 TEXTUAL-CONVENTION, 836 DisplayString, 837 TruthValue, 838 TimeStamp 839 FROM SNMPv2-TC -- RFC 2579 840 MODULE-COMPLIANCE, 841 NOTIFICATION-GROUP, 842 OBJECT-GROUP 843 FROM SNMPv2-CONF -- RFC 2580 844 SnmpAdminString 845 FROM SNMP-FRAMEWORK-MIB -- RFC 3411 846 InetAddressType, 847 InetAddress, 848 InetAddressPrefixLength, 849 InetPortNumber 850 FROM INET-ADDRESS-MIB -- RFC 4001 852 natv2MIB MODULE-IDENTITY 853 LAST-UPDATED "20150205000Z" 854 -- RFC Ed.: set to publication date 855 ORGANIZATION 856 "IETF Behavior Engineering for Hindrance Avoidance 857 (BEHAVE) Working Group" 858 CONTACT-INFO 859 "Working Group Email: behave@ietf.org 860 Simon Perreault 861 Jive Communications 862 Quebec, QC 863 Canada 865 Email: sperreault@jive.com 867 Tina Tsou 868 Huawei Technologies 869 Bantian, Longgang 870 Shenzhen 518129 871 PR China 873 Email: tina.tsou.zouting@huawei.com 875 Senthil Sivakumar 876 Cisco Systems 877 7100-8 Kit Creek Road 878 Research Triangle Park, North Carolina 27709 879 USA 881 Phone: +1 919 392 5158 882 Email: ssenthil@cisco.com 884 Tom Taylor 885 PT Taylor Consulting 886 Ottawa 887 Canada 889 Email: tom.taylor.stds@gmail.com" 891 DESCRIPTION 892 "This MIB module defines the generic managed objects 893 for NAT. 895 Copyright (C) The Internet Society (2015). This 896 version of this MIB module is part of RFC yyyy; see 897 the RFC itself for full legal notices." 898 REVISION "201502050000Z" 899 -- RFC Ed.: set to publication date 900 DESCRIPTION 901 "Complete rewrite, published as RFC yyyy. 902 Replaces former version published as RFC 4008." 903 -- RFC Ed.: replace yyyy with actual RFC number and set date" 904 ::= { mib-2 TBD } 906 -- textual conventions 908 ProtocolNumber ::= TEXTUAL-CONVENTION 909 DISPLAY-HINT "d" 910 STATUS current 911 DESCRIPTION 912 "A protocol number, from the 'protocol-numbers' IANA 913 registry." 914 REFERENCE 915 "IANA Protocol Numbers, 916 http://www.iana.org/assignments/protocol-numbers/protocol- 917 numbers.xhtml#protocol-numbers-1" 918 SYNTAX Unsigned32 (0..255) 920 Natv2SubscriberIndex ::= TEXTUAL-CONVENTION 921 DISPLAY-HINT "d" 922 STATUS current 923 DESCRIPTION 924 "A unique value, greater than zero, for each subscriber 925 in the managed system. The value for each 926 subscriber MUST remain constant at least from one 927 update of the entity's natv2SubscriberDiscontinuityTime 928 object until the next update of that object. If a 929 subscriber is deleted, its assigned index value MUST NOT 930 be assigned to another subscriber at least until 931 reinitialization of the entity's management system." 932 SYNTAX Unsigned32 (1..4294967295) 934 Natv2SubscriberIndexOrZero ::= TEXTUAL-CONVENTION 935 DISPLAY-HINT "d" 936 STATUS current 937 DESCRIPTION 938 "This textual convention is an extension of the 939 Natv2SubscriberIndex convention. The latter defines a 940 greater than zero value used to identify a subscriber in 941 the managed system. This extension permits the additional 942 value of zero, which serves as a placeholder when no 943 subscriber is associated with the object." 944 SYNTAX Unsigned32 (0|1..4294967295) 946 Natv2InstanceIndex ::= TEXTUAL-CONVENTION 947 DISPLAY-HINT "d" 948 STATUS current 949 DESCRIPTION 950 "A unique value, greater than zero, for each NAT instance 951 in the managed system. It is RECOMMENDED that values are 952 assigned contiguously starting from 1. The value for each 953 NAT instance MUST remain constant at least from one 954 update of the entity's natv2InstanceDiscontinuityTime 955 object until the next update of that object. If a NAT 956 instance is deleted, its assigned index value MUST NOT 957 be assigned to another NAT instance at least until 958 reinitialization of the entity's management system." 959 SYNTAX Unsigned32 (1..4294967295) 961 Natv2PoolIndex ::= TEXTUAL-CONVENTION 962 DISPLAY-HINT "d" 963 STATUS current 964 DESCRIPTION 965 "A unique value over the containing NAT instance, greater than 966 zero, for each address pool supported by that NAT instance. 967 It is RECOMMENDED that values are assigned contiguously 968 starting from 1. The value for each address pool MUST remain 969 constant at least from one update of the entity's 970 natv2PoolDiscontinuityTime object until the next update of 971 that object. If an address pool is deleted, its assigned 972 index value MUST NOT be assigned to another address pool for 973 the same NAT instance at least until reinitialization of the 974 entity's management system." 975 SYNTAX Unsigned32 (1..4294967295) 977 Natv2PoolIndexOrZero ::= TEXTUAL-CONVENTION 978 DISPLAY-HINT "d" 979 STATUS current 980 DESCRIPTION 981 "This textual convention is an extension of the 982 Natv2PoolIndex convention. The latter defines a greater 983 than zero value used to identify address pools in the 984 managed system. This extension permits the additional 985 value of zero, which serves as a placeholder when the 986 implementation does not support address pools or no address 987 pool is configured in a given external realm." 988 SYNTAX Unsigned32 (0|1..4294967295) 990 -- notifications 992 natv2MIBNotifications OBJECT IDENTIFIER ::= { natv2MIB 0 } 994 natv2NotificationPoolUsageLow NOTIFICATION-TYPE 995 OBJECTS { natv2PoolNotifiedPortMapEntries, 996 natv2PoolNotifiedPortMapProtocol } 997 STATUS current 998 DESCRIPTION 999 "This notification is triggered when an address pool's usage 1000 becomes less than or equal to the value of the 1001 natv2PoolThresholdUsageLow object for that pool, unless the 1002 notification has been disabled by setting the value of the 1003 threshold to -1. It is reported subject to the rate 1004 limitation specified by natv2PortMapNotificationInterval. 1006 Address pool usage is calculated as the percentage of the 1007 total number of ports allocated to the address pool that are 1008 already in use, for the most-mapped protocol at the time 1009 the notification is triggered. The two returned objects are 1010 members of natv2PoolTable indexed by the NAT instance and 1011 pool indices for which the event is being reported. They 1012 give the number of port map entries using external addresses 1013 configured on the pool for the most-mapped protocol and 1014 identify that protocol at the time the notification was 1015 triggered." 1016 REFERENCE 1017 "RFC yyyy Section 3.1.2 and Section 3.3.6." 1018 ::= { natv2MIBNotifications 1 } 1020 natv2NotificationPoolUsageHigh NOTIFICATION-TYPE 1021 OBJECTS { natv2PoolNotifiedPortMapEntries, 1022 natv2PoolNotifiedPortMapProtocol } 1023 STATUS current 1024 DESCRIPTION 1025 "This notification is triggered when an address pool's usage 1026 becomes greater than or equal to the value of the 1027 natv2PoolThresholdUsageHigh object for that pool, unless 1028 the notification has been disabled by setting the value of 1029 the threshold to 0. It is reported subject to the rate 1030 limitation specified by natv2PortMapNotificationInterval. 1032 Address pool usage is calculated as the percentage of the 1033 total number of ports allocated to the address pool that are 1034 already in use, for the most-mapped protocol at the time the 1035 notification is triggered. The two returned objects are 1036 members of natv2PoolTable indexed by the NAT instance and 1037 pool indices for which the event is being reported. They 1038 give the number of port map entries using external addresses 1039 configured on the pool for the most-mapped protocol and 1040 identify that protocol at the time the notification was 1041 triggered." 1042 REFERENCE 1043 "RFC yyyy Section 3.1.2 and Section 3.3.6." 1044 ::= { natv2MIBNotifications 2 } 1046 natv2NotificationInstanceAddressMapEntriesHigh NOTIFICATION-TYPE 1047 OBJECTS { natv2InstanceAddressMapEntries, 1048 natv2InstanceAddressMapCreations } 1050 STATUS current 1051 DESCRIPTION 1052 "This notification is triggered when the value of 1053 natv2InstanceAddressMapEntries equals or exceeds the value 1054 of the natv2InstanceThresholdAddressMapEntriesHigh object 1055 for the NAT instance, unless disabled by setting that 1056 threshold to 0. Reporting is subject to the rate limitation 1057 given by natv2InstanceNotificationInterval. 1059 natv2InstanceAddressMapEntries and 1060 natv2InstanceAddressMapCreations are members of table 1061 natv2InstanceTable indexed by the identifier of the NAT 1062 instance for which the event is being reported. The values 1063 reported are those observed at the moment the notification 1064 was triggered." 1065 REFERENCE 1066 "RFC yyyy Section 3.1.2." 1067 ::= { natv2MIBNotifications 3 } 1069 natv2NotificationInstancePortMapEntriesHigh NOTIFICATION-TYPE 1070 OBJECTS { natv2InstancePortMapEntries, 1071 natv2InstancePortMapCreations } 1072 STATUS current 1073 DESCRIPTION 1074 "This notification is triggered when the value of 1075 natv2InstancePortMapEntries becomes greater than or equal to 1076 the value of natv2InstanceThresholdPortMapEntriesHigh, 1077 unless disabled by setting that threshold to 0. Reporting is 1078 subject to the rate limitation given by 1079 natv2InstanceNotificationInterval. 1081 natv2InstancePortMapEntries and 1082 natv2InstancePortMapCreations are members of table 1083 natv2InstanceTable indexed by the identifier of the NAT 1084 instance for which the event is being reported. The values 1085 reported are those observed at the moment the notification 1086 was triggered." 1087 ::= { natv2MIBNotifications 4 } 1089 natv2NotificationSubscriberPortMappingEntriesHigh 1090 NOTIFICATION-TYPE 1091 OBJECTS { natv2SubscriberPortMapEntries, 1092 natv2SubscriberPortMapCreations } 1093 STATUS current 1094 DESCRIPTION 1095 "This notification is triggered when the value of 1096 natv2SubscriberPortMapEntries for an individual subscriber 1097 becomes greater than or equal to the value of the 1098 natv2SubscriberThresholdPortMapEntriesHigh object for that 1099 subscriber, unless disabled by setting that threshold to 0. 1100 Reporting is subject to the rate limitation given by 1101 natv2SubscriberNotificationInterval. 1103 natv2SubscriberPortMapEntries and 1104 natv2SubscriberPortMapCreations are members of table 1105 natv2SubscriberTable indexed by the subscriber for 1106 which the event is being reported. The values 1107 reported are those observed at the moment the notification 1108 was triggered." 1109 ::= { natv2MIBNotifications 5 } 1111 -- Device-level objects 1113 natv2MIBDeviceObjects OBJECT IDENTIFIER ::= { natv2MIB 1 } 1115 -- subscriber table 1117 natv2SubscriberTable OBJECT-TYPE 1118 SYNTAX SEQUENCE OF Natv2SubscriberEntry 1119 MAX-ACCESS not-accessible 1120 STATUS current 1121 DESCRIPTION 1122 "Table of subscribers. As well as the subscriber index, it 1123 provides per-subscriber state and counter objects, a last 1124 discontinuity time object for the counters, and writable 1125 threshold value and limit on port consumption." 1126 REFERENCE 1127 "RFC yyyy Section 3.3.3." 1128 ::= { natv2MIBDeviceObjects 1 } 1130 natv2SubscriberEntry OBJECT-TYPE 1131 SYNTAX Natv2SubscriberEntry 1132 MAX-ACCESS not-accessible 1133 STATUS current 1134 DESCRIPTION 1135 "Each entry describes a single subscriber." 1136 INDEX { natv2SubscriberIndex } 1137 ::= { natv2SubscriberTable 1 } 1139 Natv2SubscriberEntry ::= 1140 SEQUENCE { 1141 natv2SubscriberIndex Natv2SubscriberIndex, 1142 natv2SubscriberRealm SnmpAdminString, 1143 natv2SubscriberInternalPrefixType InetAddressType, 1144 natv2SubscriberInternalPrefix InetAddress, 1145 natv2SubscriberInternalPrefixLength InetAddressPrefixLength, 1146 -- State 1147 natv2SubscriberAddressMapEntries Unsigned32, 1148 natv2SubscriberPortMapEntries Unsigned32, 1149 -- Counters and last discontinuity time 1150 natv2SubscriberTranslations Counter64, 1151 natv2SubscriberAddressMapCreations Counter64, 1152 natv2SubscriberPortMapCreations Counter64, 1153 natv2SubscriberAddressMapFailureDrops Counter64, 1154 natv2SubscriberPortMapFailureDrops Counter64, 1155 natv2SubscriberDiscontinuityTime TimeStamp, 1156 -- Read-write controls 1157 natv2SubscriberLimitPortMapEntries Unsigned32, 1158 -- Disable limit by setting to 0 (default) 1159 natv2SubscriberThresholdPortMapEntriesHigh Unsigned32, 1160 -- Disable notifications by setting threshold to 0 (default) 1161 natv2SubscriberNotificationInterval Unsigned32 1162 -- Default is 60 seconds 1163 } 1165 natv2SubscriberIndex OBJECT-TYPE 1166 SYNTAX Natv2SubscriberIndex 1167 MAX-ACCESS not-accessible 1168 STATUS current 1169 DESCRIPTION 1170 "A unique value, greater than zero, for each subscriber 1171 in the managed system. The value for each 1172 subscriber MUST remain constant at least from one 1173 update of the entity's natv2SubscriberDiscontinuityTime 1174 object until the next update of that object. If a 1175 subscriber is deleted, its assigned index value MUST NOT 1176 be assigned to another subscriber at least until 1177 reinitialization of the entity's management system." 1178 ::= { natv2SubscriberEntry 1 } 1180 -- Configuration for this subscriber: realm, internal address(es) 1182 natv2SubscriberInternalRealm OBJECT-TYPE 1183 SYNTAX SnmpAdminString (SIZE(0..32)) 1184 MAX-ACCESS read-only 1185 STATUS current 1186 DESCRIPTION 1187 "The address realm to which this subscriber belongs. A realm 1188 defines an address space. All NATs support at least two 1189 realms. 1191 The default realm for subscribers is 'internal'. 1192 Administrators can set other values for individual 1193 subscribers when they are configured. The administrator MAY 1194 configure a new value of natv2SubscriberRealm at any time 1195 subsequent to initial configuration of the subscriber. If 1196 this happens, it MUST be treated as a point of discontinuity 1197 requiring an update of natv2SubscriberDiscontinuityTime. 1199 When the subscriber sends a packet to the NAT through a 1200 DS-Lite [RFC 6333] tunnel, this is the realm of the outer 1201 packet header source address. Other tunneled access is out 1202 of scope." 1203 REFERENCE 1204 "Address realm: RFC 2663. DS-Lite: RFC 6333." 1205 DEFVAL 1206 { "internal" } 1207 ::= { natv2SubscriberEntry 2 } 1209 natv2SubscriberInternalPrefixType OBJECT-TYPE 1210 SYNTAX InetAddressType 1211 MAX-ACCESS read-only 1212 STATUS current 1213 DESCRIPTION 1214 "Subscriber's internal prefix type. Any value other than 1215 ipv4(1) or ipv6(2) would be unexpected. In the case of 1216 DS-Lite access, this is the prefix type (IPv6(2)) used in 1217 the outer packet header." 1218 REFERENCE 1219 "DS-Lite: RFC 6333." 1220 ::= { natv2SubscriberEntry 3 } 1222 natv2SubscriberInternalPrefix OBJECT-TYPE 1223 SYNTAX InetAddress 1224 MAX-ACCESS read-only 1225 STATUS current 1226 DESCRIPTION 1227 "Prefix assigned to a subscriber's CPE. Source addresses of 1228 packets outgoing from the subscriber will be contained 1229 within this prefix. In the case of DS-Lite access, 1230 the source address taken from the prefix will be 1231 that of the outer header." 1232 REFERENCE 1233 "DS-Lite: RFC 6333." 1234 ::= { natv2SubscriberEntry 4 } 1236 natv2SubscriberInternalPrefixLength OBJECT-TYPE 1237 SYNTAX InetAddressPrefixLength 1238 MAX-ACCESS read-only 1239 STATUS current 1240 DESCRIPTION 1241 "Length of the prefix assigned to a subscriber's CPE, in 1242 bits. If a single address is assigned, this will be 32 1243 for IPv4 and 128 for IPv6." 1244 ::= { natv2SubscriberEntry 5 } 1246 -- State objects 1248 natv2SubscriberAddressMapEntries OBJECT-TYPE 1249 SYNTAX Unsigned32 1250 MAX-ACCESS read-only 1251 STATUS current 1252 DESCRIPTION 1253 "The current number of address map entries for the 1254 subscriber, including static mappings. An address map entry 1255 maps from a given internal address and realm to an external 1256 address in a particular external realm. This definition 1257 includes 'hairpin' mappings, where the external realm is the 1258 same as the internal one. Address map entries are also 1259 tracked per instance and per address pool within the 1260 instance." 1261 REFERENCE 1262 "RFC yyyy Section 3.3.8." 1263 ::= { natv2SubscriberEntry 6 } 1265 natv2SubscriberPortMapEntries OBJECT-TYPE 1266 SYNTAX Unsigned32 1267 MAX-ACCESS read-only 1268 STATUS current 1269 DESCRIPTION 1270 "The current number of port map entries in the port map table 1271 for the subscriber, including static mappings. A port map 1272 entry maps from a given external realm, address, and port 1273 for a given protocol to an internal realm, address, and 1274 port. This definition includes 'hairpin' mappings, where the 1275 external realm is the same as the internal one. Port map 1276 entries are also tracked per instance and per protocol and 1277 address pool within the instance." 1278 REFERENCE 1279 "RFC yyyy Section 3.3.9." 1280 ::= { natv2SubscriberEntry 7 } 1282 -- Counters and last discontinuity time 1284 natv2SubscriberTranslations OBJECT-TYPE 1285 SYNTAX Counter64 1286 MAX-ACCESS read-only 1287 STATUS current 1288 DESCRIPTION 1289 "The cumulative number of translated packets received from or 1290 sent to this subscriber. This value MUST be monotone 1291 increasing in the periods between updates of the entity's 1292 natv2SubscriberDiscontinuityTime. If a manager detects a 1293 change in the latter since the last time it sampled this 1294 counter, it SHOULD NOT make use of the difference between 1295 the latest value of the counter and any value retrieved 1296 before the new value of natv2SubscriberDiscontinuityTime." 1297 ::= { natv2SubscriberEntry 8 } 1299 natv2SubscriberAddressMapCreations OBJECT-TYPE 1300 SYNTAX Counter64 1301 MAX-ACCESS read-only 1302 STATUS current 1303 DESCRIPTION 1304 "The cumulative number of address map entries created for 1305 this subscriber, including static mappings. Address map 1306 entries are also tracked per instance and per protocol and 1307 address pool within the instance. 1309 This value MUST be monotone increasing in 1310 the periods between updates of the entity's 1311 natv2SubscriberDiscontinuityTime. If a manager detects a 1312 change in the latter since the last time it sampled this 1313 counter, it SHOULD NOT make use of the difference between 1314 the latest value of the counter and any value retrieved 1315 before the new value of natv2SubscriberDiscontinuityTime." 1316 ::= { natv2SubscriberEntry 9 } 1318 natv2SubscriberPortMapCreations OBJECT-TYPE 1319 SYNTAX Counter64 1320 MAX-ACCESS read-only 1321 STATUS current 1322 DESCRIPTION 1323 "The cumulative number of port map entries created for this 1324 subscriber, including static mappings. Port map entries are 1325 also tracked per instance and per protocol and address pool 1326 within the instance. 1328 This value MUST be monotone increasing in the periods 1329 between updates of the entity's 1330 natv2SubscriberDiscontinuityTime. If a manager detects a 1331 change in the latter since the last time it sampled this 1332 counter, it SHOULD NOT make use of the difference between 1333 the latest value of the counter and any value retrieved 1334 before the new value of natv2SubscriberDiscontinuityTime." 1335 ::= { natv2SubscriberEntry 10 } 1337 natv2SubscriberAddressMapFailureDrops OBJECT-TYPE 1338 SYNTAX Counter64 1339 MAX-ACCESS read-only 1340 STATUS current 1341 DESCRIPTION 1342 "The cumulative number of packets originated by this 1343 subscriber that were dropped because the packet would have 1344 triggered the creation of a new address map entry, but no 1345 address could be allocated in the selected external realm 1346 because all addresses from the selected address pool (or the 1347 whole realm, if no address pool has been configured for that 1348 realm) have already been fully allocated. 1350 This value MUST be monotone increasing in the periods 1351 between updates of the entity's 1352 natv2SubscriberDiscontinuityTime. If a manager detects a 1353 change in the latter since the last time it sampled this 1354 counter, it SHOULD NOT make use of the difference between 1355 the latest value of the counter and any value retrieved 1356 before the new value of natv2SubscriberDiscontinuityTime." 1357 ::= { natv2SubscriberEntry 11 } 1359 natv2SubscriberPortMapFailureDrops OBJECT-TYPE 1360 SYNTAX Counter64 1361 MAX-ACCESS read-only 1362 STATUS current 1363 DESCRIPTION 1364 "The cumulative number of packets dropped because the 1365 packet would have triggered the creation of a new 1366 port mapping, but no port could be allocated for the 1367 protocol concerned. The usual case for this will be 1368 for a NAT instance that supports address pooling and 1369 the 'paired' pooling behavior recommended by RFC 4787, 1370 where the internal endpoint has used up all of the 1371 ports allocated to it for the address it was mapped to 1372 in the selected address pool in the external realm 1373 concerned and cannot be given more ports because 1374 - policy or implementation prevents it from having a 1375 second address in the same pool, and 1376 - policy or unavailability prevents it from acquiring 1377 more ports at its originally assigned address. 1379 If the NAT instance supports address pooling but its 1380 pooling behavior is 'arbitrary' (meaning that 1381 the NAT instance can allocate a new port mapping for 1382 the given internal endpoint on any address in the 1383 selected address pool and is not bound to what it has 1384 already mapped for that endpoint), then this counter 1385 is incremented when all ports for the protocol concerned 1386 over the whole of the selected address pool are already 1387 in use. 1389 As a third case, if no address pools have been configured 1390 for the external realm concerned, then this counter is 1391 incremented because all ports for the protocol involved over 1392 the whole set of addresses available for that external realm 1393 are already in use. 1395 Finally, this counter is incremented if the packet would 1396 have triggered the creation of a new port mapping, but the 1397 current value of natv2SubscriberPortMapEntries equals or 1398 exceeds the value of natv2SubscriberLimitPortMapEntries 1399 for this subscriber (unless that limit is disabled). 1401 This value MUST be monotone increasing in the periods 1402 between updates of the entity's 1403 natv2SubscriberDiscontinuityTime. If a manager detects a 1404 change in the latter since the last time it sampled this 1405 counter, it SHOULD NOT make use of the difference between 1406 the latest value of the counter and any value retrieved 1407 before the new value of natv2SubscriberDiscontinuityTime." 1408 REFERENCE 1409 "Pooling behavior: RFC 4787, end of section 4.1." 1410 ::= { natv2SubscriberEntry 12 } 1412 natv2SubscriberDiscontinuityTime OBJECT-TYPE 1413 SYNTAX TimeStamp 1414 MAX-ACCESS read-only 1415 STATUS current 1416 DESCRIPTION 1417 "Snapshot of the value of the sysUpTime object at the 1418 beginning of the latest period of continuity of the 1419 statistical counters associated with this subscriber." 1420 ::= { natv2SubscriberEntry 14 } 1422 -- Per-subscriber limit and threshold on port mappings 1423 -- Disabled if set to zero 1424 natv2SubscriberLimitPortMapEntries OBJECT-TYPE 1425 SYNTAX Unsigned32 1426 MAX-ACCESS read-write 1427 STATUS current 1428 DESCRIPTION 1429 "Limit on total number of port mappings active for this 1430 subscriber (natv2SubscriberPortMapEntries). Once this limit 1431 is reached, packets that might have triggered new port 1432 mappings are dropped. The number of such packets dropped is 1433 counted in natv2InstancePortMapFailureDrops. 1435 Limit is disabled if set to zero (default)." 1436 DEFVAL 1437 { 0 } 1438 ::= { natv2SubscriberEntry 15 } 1440 natv2SubscriberThresholdPortMapEntriesHigh OBJECT-TYPE 1441 SYNTAX Unsigned32 1442 MAX-ACCESS read-write 1443 STATUS current 1444 DESCRIPTION 1445 "Notification threshold for total number of port mappings 1446 active for this subscriber. Whenever 1447 natv2SubscriberPortMapEntries is updated, if it equals or 1448 exceeds natv2SubscriberThresholdPortMapEntriesHigh, the 1449 notification 1450 natv2NotificationSubscriberPortMappingEntriesHigh is 1451 triggered, unless the notification is disabled by setting 1452 the threshold to 0. Reporting is subject to the minimum 1453 inter-notification interval given by 1454 natv2SubscriberNotificationInterval. If multiple 1455 notifications are triggered during one interval, the agent 1456 MUST report only the one containing the highest value of 1457 natv2SubscriberPortMapEntries and discard the others." 1458 DEFVAL 1459 { 0 } 1460 ::= { natv2SubscriberEntry 16 } 1462 natv2SubscriberNotificationInterval OBJECT-TYPE 1463 SYNTAX Unsigned32 (1..3600) 1464 UNITS 1465 "Seconds" 1466 MAX-ACCESS read-write 1467 STATUS current 1468 DESCRIPTION 1469 "Minimum number of seconds (default 60) between successive 1470 reporting of notifications for this subscriber. Controls the 1471 reporting of 1472 natv2NotificationSubscriberPortMappingEntriesHigh." 1473 DEFVAL 1474 { 60 } 1475 ::= { natv2SubscriberEntry 17 } 1477 -- Per-NAT-instance objects 1479 natv2MIBInstanceObjects OBJECT IDENTIFIER ::= { natv2MIB 2 } 1480 -- Instance table 1482 natv2InstanceTable OBJECT-TYPE 1483 SYNTAX SEQUENCE OF Natv2InstanceEntry 1484 MAX-ACCESS not-accessible 1485 STATUS current 1486 DESCRIPTION 1487 "Table of NAT instances. As well as state and counter 1488 objects, it provides the instance index, instance name, and 1489 the last discontinuity time object which is applicable to 1490 the counters. It also contains writable thresholds for 1491 reporting of notifications and limits on usage of resources 1492 at the level of the NAT instance. 1494 It is assumed that NAT instances can be created and deleted 1495 dynamically, but this MIB module does not provide the means 1496 to do so. For restrictions on assignment and maintenance of 1497 the NAT index instance see the description of 1498 natv2InstanceIndex in the table below. For the requirements 1499 on maintenance of the values of the counters in this table 1500 see the description of natv2InstanceDiscontinuityTime in 1501 this table. 1503 Each NAT instance has its own resources and behavior. The 1504 resources include memory as reflected in space for map 1505 entries, processing power as reflected in the rate of map 1506 creation and deletion, and mappable addresses in each realm 1507 that can play the role of an external realm for at least 1508 some mappings for that instance. The NAT instance table 1509 includes limits and notification thresholds that relate to 1510 memory usage for mapping at the level of the whole instance. 1511 The limit on number of subscribers with active mappings is a 1512 limit to some extent on processor usage. 1514 The mappable 'external' addresses may or may not be 1515 organized into address pools. For a definition of address 1516 pools see the description of natv2PoolTable. If the instance 1517 does support address pools, it also has a pooling behavior. 1518 Mapping, filtering, and pooling behavior are defined in the 1519 descriptions of the natv2InstancePortMappingBehavior, 1520 natv2InstanceFilteringBehavior, and 1521 natv2InstancePoolingBehavior objects in this table. The 1522 instance also has a fragmentation behavior, defined in the 1523 description of the natv2InstanceFragmentBehavior object." 1524 REFERENCE 1525 "RFC yyyy Section 3.3.4. NAT behaviors: RFC 4787 1526 (primary, UDP); RFC 5382 (TCP), RFC 5508 (ICMP), RFC5597 1527 (DCCP)." 1529 ::= { natv2MIBInstanceObjects 1 } 1531 natv2InstanceEntry OBJECT-TYPE 1532 SYNTAX Natv2InstanceEntry 1533 MAX-ACCESS not-accessible 1534 STATUS current 1535 DESCRIPTION 1536 "Objects related to a single NAT instance." 1537 INDEX { natv2InstanceIndex } 1538 ::= { natv2InstanceTable 1 } 1540 Natv2InstanceEntry ::= 1541 SEQUENCE { 1542 natv2InstanceIndex Natv2InstanceIndex, 1543 natv2InstanceAlias DisplayString, 1544 -- Configured behaviors 1545 natv2InstancePortMappingBehavior INTEGER, 1546 natv2InstanceFilteringBehavior INTEGER, 1547 natv2InstancePoolingBehavior INTEGER, 1548 natv2InstanceFragmentBehavior INTEGER, 1549 -- State 1550 natv2InstanceAddressMapEntries Unsigned32, 1551 natv2InstancePortMapEntries Unsigned32, 1552 -- Statistics and discontinuity time 1553 natv2InstanceTranslations Counter64, 1554 natv2InstanceAddressMapCreations Counter64, 1555 natv2InstancePortMapCreations Counter64, 1556 natv2InstanceAddressMapEntryLimitDrops Counter64, 1557 natv2InstancePortMapEntryLimitDrops Counter64, 1558 natv2InstanceSubscriberActiveLimitDrops Counter64, 1559 natv2InstanceAddressMapFailureDrops Counter64, 1560 natv2InstancePortMapFailureDrops Counter64, 1561 natv2InstanceFragmentDrops Counter64, 1562 natv2InstanceOtherResourceFailureDrops Counter64, 1563 natv2InstanceDiscontinuityTime TimeStamp, 1564 -- Notification thresholds, disabled if set to 0 1565 natv2InstanceThresholdAddressMapEntriesHigh Unsigned32, 1566 natv2InstanceThresholdPortMapEntriesHigh Unsigned32, 1567 natv2InstanceNotificationInterval Unsigned32, 1568 -- Limits, disabled if set to 0 1569 natv2InstanceLimitAddressMapEntries Unsigned32, 1570 natv2InstanceLimitPortMapEntries Unsigned32, 1571 natv2InstanceLimitPendingFragments Unsigned32, 1572 natv2InstanceLimitSubscriberActives Unsigned32 1573 } 1575 natv2InstanceIndex OBJECT-TYPE 1576 SYNTAX Natv2InstanceIndex 1577 MAX-ACCESS not-accessible 1578 STATUS current 1579 DESCRIPTION 1580 "NAT instance index. It is up to the implementation to 1581 determine which values correspond to in-service NAT 1582 instances. This object is used as an index for all tables 1583 defined below." 1584 ::= { natv2InstanceEntry 1 } 1586 natv2InstanceAlias OBJECT-TYPE 1587 SYNTAX DisplayString (SIZE (0..64)) 1588 MAX-ACCESS read-only 1589 STATUS current 1590 DESCRIPTION 1591 "This object is an 'alias' name for the NAT instance as 1592 specified by a network manager, and provides a non-volatile 1593 'handle' for the instance. 1595 An example of the value which a network manager might store 1596 in this object for a NAT instance is the name/identifier of 1597 the interface that brings in internal traffic for this NAT 1598 instance or the name of the VRF for internal traffic." 1599 ::= { natv2InstanceEntry 2 } 1601 -- Configured behaviors 1603 natv2InstancePortMappingBehavior OBJECT-TYPE 1604 MAX-ACCESS read-only 1605 STATUS current 1606 DESCRIPTION 1607 "Port mapping behavior is the policy governing selection of 1608 external address and port in a given realm for a given 1609 five-tuple of source address and port, destination address 1610 and port, and protocol. 1612 endpointIndependent(0), the behavior REQUIRED by RFC 4787 1613 REQ-1, maps the source address and port to the same 1614 external address and port for all destination address and 1615 port combinations reached through the same external realm 1616 and using the given protocol. 1618 addressDependent(1) maps to the same external address and 1619 port for all destination ports at the same destination 1620 address reached through the same external realm and using 1621 the given protocol. 1623 addressAndPortDependent(2) maps to a separate external 1624 address and port combination for each different 1625 destination address and port combination reached through 1626 the same external realm." 1627 REFERENCE 1628 "RFC 4787 section 4.1." 1629 SYNTAX INTEGER { 1630 endpointIndependent (0), 1631 addressDependent (1), 1632 addressAndPortDependent (2) 1633 } 1634 ::= { natv2InstanceEntry 3 } 1636 natv2InstanceFilteringBehavior OBJECT-TYPE 1637 MAX-ACCESS read-only 1638 STATUS current 1639 DESCRIPTION 1640 "Filtering behavior is the policy governing acceptance or 1641 dropping of packets incoming from remote sources via a 1642 given external realm and destined to a specific three-tuple 1643 of external address, port, and protocol at the NAT instance 1644 that has been assigned in a port mapping. 1646 endpointIndependent(0) accepts for translation packets from 1647 all combinations of remote address and port destined to the 1648 mapped external address and port via the given external 1649 realm and using the given protocol. 1651 addressDependent(1) accepts for translation packets from all 1652 remote ports from the same remote source address destined to 1653 the mapped external address and port via the given external 1654 realm and using the given protocol. 1656 addressAndPortDependent(2) accepts for translation only 1657 those packets with the same remote source address, port, and 1658 protocol incoming from the same external realm as identified 1659 when the applicable port map entry was created. 1661 RFC 4787 REQ-8 recommends either endpointIndependent(0) or 1662 addressDependent(1) filtering behavior depending on whether 1663 application-friendliness or security takes priority." 1664 REFERENCE 1665 "RFC 4787 section 5." 1666 SYNTAX INTEGER { 1667 endpointIndependent (0), 1668 addressDependent (1), 1669 addressAndPortDependent (2) 1670 } 1671 ::= { natv2InstanceEntry 4 } 1673 natv2InstancePoolingBehavior OBJECT-TYPE 1674 MAX-ACCESS read-only 1675 STATUS current 1676 DESCRIPTION 1677 "Pooling behavior is the policy used to select the address 1678 for a new port mapping within a given address pool to which 1679 the internal address has already been mapped. 1681 arbitrary(0) pooling behavior means that the NAT instance 1682 may create the new port mapping using any address in the 1683 pool that has a free port for the protocol concerned. 1685 paired(1) pooling behavior, the behavior RECOMMENDED by RFC 1686 4787 REQ-2, means that once a given internal address has 1687 been mapped to a particular address in a particular pool, 1688 further mappings of the same internal address to that pool 1689 will reuse the previously assigned pool member address." 1690 REFERENCE 1691 "RFC 4787 near the end of section 4.1" 1692 SYNTAX INTEGER { 1693 arbitrary (0), 1694 paired (1) 1695 } 1696 ::= { natv2InstanceEntry 5 } 1698 natv2InstanceFragmentBehavior OBJECT-TYPE 1699 MAX-ACCESS read-only 1700 STATUS current 1701 DESCRIPTION 1702 "Fragment behavior is the NAT instance's capability to 1703 receive and translate fragments incoming from remote 1704 sources. 1706 fragmentNone(0) implies no capability to translate incoming 1707 fragments, so all received fragments are dropped. Each 1708 dropped fragment is counted in natv2InstanceFragmentDrops. 1710 fragmentInOrder(1) implies the ability to translate 1711 fragments only if they are received in order, so that in 1712 particular the header is in the first packet. If a fragment 1713 is received out of order, it is dropped and counted in 1714 natv2InstanceFragmentDrops. 1716 fragmentOutOfOrder(2), the capability REQUIRED by RFC 4787 1717 REQ-14, implies the capability to translate fragments even 1718 when they arrive out of order, subject to a protective 1719 limit natv2InstanceLimitPendingFragments on total number of 1720 fragments awaiting the first fragment of the chain. If the 1721 implementation supports this capability, 1722 natv2InstanceFragmentDrops is incremented only when a new 1723 fragment arrives but is dropped because the limit on pending 1724 fragments has already been reached." 1725 REFERENCE 1726 "RFC 4787 section 11." 1727 SYNTAX INTEGER { 1728 fragmentNone (0), 1729 fragmentInOrder (1), 1730 fragmentOutOfOrder (2) 1731 ::= { natv2InstanceEntry 6 } 1733 -- State 1735 natv2InstanceAddressMapEntries OBJECT-TYPE 1736 SYNTAX Unsigned32 1737 MAX-ACCESS read-only 1738 STATUS current 1739 DESCRIPTION 1740 "The current number of address map entries in total over the 1741 whole NAT instance, including static mappings. An address 1742 map entry maps from a given internal address and realm to an 1743 external address in a particular external realm. This 1744 definition includes 'hairpin' mappings, where the external 1745 realm is the same as the internal one. Address map entries 1746 are also tracked per subscriber and per address pool within 1747 the instance." 1748 REFERENCE 1749 "RFC yyyy Section 3.3.8. RFC 4787 section 6." 1750 ::= { natv2InstanceEntry 7 } 1752 natv2InstancePortMapEntries OBJECT-TYPE 1753 SYNTAX Unsigned32 1754 MAX-ACCESS read-only 1755 STATUS current 1756 DESCRIPTION 1757 "The current number of entries in the port map table in total 1758 over the whole NAT instance, including static mappings. A 1759 port map entry maps from a given external realm, address, 1760 and port for a given protocol to an internal realm, address, 1761 and port. This definition includes 'hairpin' mappings, where 1762 the external realm is the same as the internal one. Port map 1763 entries are also tracked per subscriber and per protocol and 1764 address pool within the instance." 1765 REFERENCE 1766 "RFC yyyy Section 3.3.9. 1767 Hairpinning: RFC 4787 Section 6." 1768 ::= { natv2InstanceEntry 8 } 1770 -- Statistics 1772 natv2InstanceTranslations OBJECT-TYPE 1773 SYNTAX Counter64 1774 MAX-ACCESS read-only 1775 STATUS current 1776 DESCRIPTION 1777 "The cumulative number of translated packets passing through 1778 this NAT instance. This value MUST be monotone increasing in 1779 the periods between updates of 1780 natv2InstanceDiscontinuityTime. If a manager detects a 1781 change in the latter since the last time it sampled this 1782 counter, it SHOULD NOT make use of the difference between 1783 the latest value of the counter and any value retrieved 1784 before the new value of natv2InstanceDiscontinuityTime." 1785 ::= { natv2InstanceEntry 9 } 1787 natv2InstanceAddressMapCreations OBJECT-TYPE 1788 SYNTAX Counter64 1789 MAX-ACCESS read-only 1790 STATUS current 1791 DESCRIPTION 1792 "The cumulative number of address map entries created by the 1793 NAT instance, including static mappings. Address map 1794 creations are also tracked per address pool within the 1795 instance and per subscriber. 1797 This value MUST be monotone increasing in 1798 the periods between updates of 1799 natv2InstanceDiscontinuityTime. If a manager detects a 1800 change in the latter since the last time it sampled this 1801 counter, it SHOULD NOT make use of the difference between 1802 the latest value of the counter and any value retrieved 1803 before the new value of natv2InstanceDiscontinuityTime." 1804 ::= { natv2InstanceEntry 10 } 1806 natv2InstancePortMapCreations OBJECT-TYPE 1807 SYNTAX Counter64 1808 MAX-ACCESS read-only 1809 STATUS current 1810 DESCRIPTION 1811 "The cumulative number of port map entries created by the 1812 NAT instance, including static mappings. Port map 1813 creations are also tracked per protocol and address pool 1814 within the instance and per subscriber. 1816 This value MUST be monotone increasing in 1817 the periods between updates of 1818 natv2InstanceDiscontinuityTime. If a manager detects a 1819 change in the latter since the last time it sampled this 1820 counter, it SHOULD NOT make use of the difference between 1821 the latest value of the counter and any value retrieved 1822 before the new value of natv2InstanceDiscontinuityTime." 1823 ::= { natv2InstanceEntry 11 } 1825 natv2InstanceAddressMapEntryLimitDrops OBJECT-TYPE 1826 SYNTAX Counter64 1827 MAX-ACCESS read-only 1828 STATUS current 1829 DESCRIPTION 1830 "The cumulative number of packets dropped rather than 1831 translated because the packet would have triggered 1832 the creation of a new address map entry but the limit 1833 on number of address map entries for the NAT instance 1834 given by natv2InstanceLimitAddressMapEntries has 1835 already been reached. 1837 This value MUST be monotone increasing in the periods 1838 between updates of the entity's 1839 natv2InstanceDiscontinuityTime. If a manager detects a 1840 change in the latter since the last time it sampled this 1841 counter, it SHOULD NOT make use of the difference between 1842 the latest value of the counter and any value retrieved 1843 before the new value of natv2InstanceDiscontinuityTime." 1844 ::= { natv2InstanceEntry 12 } 1846 natv2InstancePortMapEntryLimitDrops OBJECT-TYPE 1847 SYNTAX Counter64 1848 MAX-ACCESS read-only 1849 STATUS current 1850 DESCRIPTION 1851 "The cumulative number of packets dropped rather than 1852 translated because the packet would have triggered 1853 the creation of a new port map entry but the limit 1854 on number of port map entries for the NAT instance 1855 given by natv2InstanceLimitPortMapEntries has 1856 already been reached. 1858 This value MUST be monotone increasing in the periods 1859 between updates of the entity's 1860 natv2InstanceDiscontinuityTime. If a manager detects a 1861 change in the latter since the last time it sampled this 1862 counter, it SHOULD NOT make use of the difference between 1863 the latest value of the counter and any value retrieved 1864 before the new value of natv2InstanceDiscontinuityTime." 1865 ::= { natv2InstanceEntry 13 } 1867 natv2InstanceSubscriberActiveLimitDrops OBJECT-TYPE 1868 SYNTAX Counter64 1869 MAX-ACCESS read-only 1870 STATUS current 1871 DESCRIPTION 1872 "The cumulative number of packets dropped rather than 1873 translated because the packet would have triggered the 1874 creation of a new mapping for a subscriber with no other 1875 active mappings, but the limit on number of active 1876 subscribers for the NAT instance given by 1877 natv2InstanceLimitSubscriberActives has already been 1878 reached. 1880 This value MUST be monotone increasing in the periods 1881 between updates of the entity's 1882 natv2InstanceDiscontinuityTime. If a manager detects a 1883 change in the latter since the last time it sampled this 1884 counter, it SHOULD NOT make use of the difference between 1885 the latest value of the counter and any value retrieved 1886 before the new value of natv2InstanceDiscontinuityTime." 1887 ::= { natv2InstanceEntry 14 } 1889 natv2InstanceAddressMapFailureDrops OBJECT-TYPE 1890 SYNTAX Counter64 1891 MAX-ACCESS read-only 1892 STATUS current 1893 DESCRIPTION 1894 "The cumulative number of packets dropped because the packet 1895 would have triggered the creation of a new address map 1896 entry, but no address could be allocated in the selected 1897 external realm because all addresses from the selected 1898 address pool (or the whole realm, if no address pool has 1899 been configured for that realm) have already been fully 1900 allocated. 1902 This value MUST be monotone increasing in the periods 1903 between updates of the entity's 1904 natv2InstanceDiscontinuityTime. If a manager detects a 1905 change in the latter since the last time it sampled this 1906 counter, it SHOULD NOT make use of the difference between 1907 the latest value of the counter and any value retrieved 1908 before the new value of natv2InstanceDiscontinuityTime." 1909 ::= { natv2InstanceEntry 15 } 1911 natv2InstancePortMapFailureDrops OBJECT-TYPE 1912 SYNTAX Counter64 1913 MAX-ACCESS read-only 1914 STATUS current 1915 DESCRIPTION 1916 "The cumulative number of packets dropped because the 1917 packet would have triggered the creation of a new 1918 port map entry, but no port could be allocated for the 1919 protocol concerned. The usual case for this will be 1920 for a NAT instance that supports address pooling and 1921 the 'paired' pooling behavior recommended by RFC 4787, 1922 where the internal endpoint has used up all of the 1923 ports allocated to it for the address it was mapped to 1924 in the selected address pool in the external realm 1925 concerned and cannot be given more ports because 1926 - policy or implementation prevents it from having a 1927 second address in the same pool, and 1928 - policy or unavailability prevents it from acquiring 1929 more ports at its originally assigned address. 1931 If the NAT instance supports address pooling but its 1932 pooling behavior is 'arbitrary' (meaning that 1933 the NAT instance can allocate a new port mapping for 1934 the given internal endpoint on any address in the 1935 selected address pool and is not bound to what it has 1936 already mapped for that endpoint), then this counter 1937 is incremented when all ports for the protocol concerned 1938 over the whole of the selected address pool are already 1939 in use. 1941 Finally, if no address pools have been configured for the 1942 external realm concerned, then this counter is incremented 1943 because all ports for the protocol involved over the whole 1944 set of addresses available for that external realm are 1945 already in use. 1947 This value MUST be monotone increasing in the periods 1948 between updates of the entity's 1949 natv2InstanceDiscontinuityTime. If a manager detects a 1950 change in the latter since the last time it sampled this 1951 counter, it SHOULD NOT make use of the difference between 1952 the latest value of the counter and any value retrieved 1953 before the new value of natv2InstanceDiscontinuityTime." 1954 REFERENCE 1955 "Pooling behavior: RFC 4787, end of section 4.1." 1956 ::= { natv2InstanceEntry 16 } 1958 natv2InstanceFragmentDrops OBJECT-TYPE 1959 SYNTAX Counter64 1960 MAX-ACCESS read-only 1961 STATUS current 1962 DESCRIPTION 1963 "The cumulative number of fragments received by the NAT 1964 instance but dropped rather than translated. When the NAT 1965 instance supports the 'Receive Fragment Out of Order' 1966 capability as required by RFC 4787, this occurs because the 1967 fragment was received out of order and would be added to the 1968 queue of fragments awaiting the initial fragment of the 1969 chain, but the queue has already reached the limit set by 1970 natv2InstanceLimitsPendingFragments. Counting in other cases 1971 is specified in the description of 1972 natv2InstanceFragmentBehavior. 1974 This value MUST be monotone increasing in the periods 1975 between updates of the entity's 1976 natv2InstanceDiscontinuityTime. If a manager detects a 1977 change in the latter since the last time it sampled this 1978 counter, it SHOULD NOT make use of the difference between 1979 the latest value of the counter and any value retrieved 1980 before the new value of natv2InstanceDiscontinuityTime." 1981 REFERENCE 1982 "RFC 4787, section 11." 1983 ::= { natv2InstanceEntry 17 } 1985 natv2InstanceOtherResourceFailureDrops OBJECT-TYPE 1986 SYNTAX Counter64 1987 MAX-ACCESS read-only 1988 STATUS current 1989 DESCRIPTION 1990 "The cumulative number of packets dropped because of 1991 unavailability of a resource other than an address or port 1992 that would have been required to process it. The most likely 1993 case is where the upper layer protocol in the packet is not 1994 supported by the NAT instance. 1996 This value MUST be monotone increasing in the periods 1997 between updates of the entity's 1998 natv2InstanceDiscontinuityTime. If a manager detects a 1999 change in the latter since the last time it sampled this 2000 counter, it SHOULD NOT make use of the difference between 2001 the latest value of the counter and any value retrieved 2002 before the new value of natv2InstanceDiscontinuityTime." 2003 ::= { natv2InstanceEntry 18 } 2005 natv2InstanceDiscontinuityTime OBJECT-TYPE 2006 SYNTAX TimeStamp 2007 MAX-ACCESS read-only 2008 STATUS current 2009 DESCRIPTION 2010 "Snapshot of the value of the sysUpTime object at the 2011 beginning of the latest period of continuity of the 2012 statistical counters associated with this NAT instance." 2013 ::= { natv2InstanceEntry 19 } 2015 -- Notification thresholds, disabled by setting to zero 2017 natv2InstanceThresholdAddressMapEntriesHigh OBJECT-TYPE 2018 SYNTAX Unsigned32 2019 MAX-ACCESS read-write 2020 STATUS current 2021 DESCRIPTION 2022 "Notification threshold for total number of address map 2023 entries held by this NAT instance. Whenever 2024 natv2InstanceAddressMapEntries is updated, if it equals or 2025 exceeds natv2InstanceThresholdAddressMapEntriesHigh, then 2026 natv2NotificationInstanceAddressMapEntriesHigh may be 2027 triggered, unless the notification is disabled by setting 2028 the threshold to 0. Reporting is subject to the minimum 2029 inter-notification interval given by 2030 natv2InstanceNotificationInterval. If multiple notifications 2031 are triggered during one interval, the agent MUST report 2032 only the one containing the highest value of 2033 natv2InstanceAddressMapEntries and discard the others." 2034 DEFVAL 2035 { 0 } 2036 ::= { natv2InstanceEntry 20 } 2038 natv2InstanceThresholdPortMapEntriesHigh OBJECT-TYPE 2039 SYNTAX Unsigned32 2040 MAX-ACCESS read-write 2041 STATUS current 2042 DESCRIPTION 2043 "Notification threshold for total number of port map 2044 entries held by this NAT instance. Whenever 2045 natv2InstancePortMapEntries is updated, if it equals or 2046 exceeds natv2InstanceThresholdPortMapEntriesHigh, then 2047 natv2NotificationInstancePortMapEntriesHigh may be 2048 triggered, unless the notification is disabled by setting 2049 the threshold to 0. Reporting is subject to the minimum 2050 inter-notification interval given by 2051 natv2InstanceNotificationInterval. If multiple notifications 2052 are triggered during one interval, the agent MUST report 2053 only the one containing the highest value of 2054 natv2InstancePortMapEntries and discard the others." 2055 DEFVAL 2056 { 0 } 2057 ::= { natv2InstanceEntry 21 } 2059 natv2InstanceNotificationInterval OBJECT-TYPE 2060 SYNTAX Unsigned32 (1..3600) 2061 UNITS 2062 "Seconds" 2063 MAX-ACCESS read-write 2064 STATUS current 2065 DESCRIPTION 2066 "Minimum number of seconds (default 10) between successive 2067 notifications for this NAT instance. Controls the reporting 2068 of natv2NotificationInstanceAddressMapEntriesHigh and 2069 natv2NotificationInstancePortMapEntriesHigh." 2070 DEFVAL 2071 { 10 } 2072 ::= { natv2InstanceEntry 22 } 2074 -- Limits, disabled if set to 0 2076 natv2InstanceLimitAddressMapEntries OBJECT-TYPE 2077 SYNTAX Unsigned32 2078 MAX-ACCESS read-write 2079 STATUS current 2080 DESCRIPTION 2081 "Limit on total number of address map entries supported by 2082 the NAT instance. When natv2InstanceAddressMapEntries has 2083 reached this limit, subsequent packets that would normally 2084 trigger creation of a new address map entry will be dropped 2085 and counted in natv2InstanceAddressMapEntryLimitDrops. 2086 Warning of an approach to this limit can be achieved by 2087 setting natv2InstanceThresholdAddressMapEntriesHigh to a 2088 non-zero value, for example, 80% of the limit. The limit is 2089 disabled by setting its value to zero (default value). 2091 For further information please see the descriptions of 2092 natv2NotificationInstanceAddressMapEntriesHigh and 2093 natv2InstanceAddressMapEntries." 2094 DEFVAL 2095 { 0 } 2096 ::= { natv2InstanceEntry 23 } 2098 natv2InstanceLimitPortMapEntries OBJECT-TYPE 2099 SYNTAX Unsigned32 2100 MAX-ACCESS read-write 2101 STATUS current 2102 DESCRIPTION 2103 "Limit on total number of port map entries supported by the 2104 NAT instance. When natv2InstancePortMapEntries has reached 2105 this limit, subsequent packets that would normally trigger 2106 creation of a new port map entry will be dropped and counted 2107 in natv2InstancePortMapEntryLimitDrops. Warning of an 2108 approach to this limit can be achieved by setting 2109 natv2InstanceThresholdPortMapEntriesHigh to a non-zero 2110 value, for example, 80% of the limit. The limit is disabled 2111 by setting its value to zero (default value). 2113 For further information please see the descriptions of 2114 natv2NotificationInstancePortMapEntriesHigh and 2115 natv2InstancePortMapEntries." 2116 DEFVAL 2117 { 0 } 2118 ::= { natv2InstanceEntry 24 } 2120 natv2InstanceLimitPendingFragments OBJECT-TYPE 2121 SYNTAX Unsigned32 2122 MAX-ACCESS read-write 2123 STATUS current 2124 DESCRIPTION 2125 "Limit on number of out-of-order fragments received by the 2126 NAT instance from remote sources and held until head of 2127 chain appears. While the number of held fragments is at this 2128 limit, subsequent packets that contain fragments not 2129 relating to those already held will be dropped and counted 2130 in natv2InstancePendingFragmentLimitDrops. The limit is 2131 disabled by setting the value to zero (default value). 2133 Applicable only when the NAT instance supports 'Receive 2134 Fragments Out of Order' behavior, leave at default 2135 otherwise. See the description of 2136 natv2InstanceFragmentBehavior." 2137 REFERENCE 2138 "RFC 4787 Section 11" 2139 DEFVAL { 0 } 2140 ::= { natv2InstanceEntry 25 } 2142 natv2InstanceLimitSubscriberActives OBJECT-TYPE 2143 SYNTAX Unsigned32 2144 MAX-ACCESS read-write 2145 STATUS current 2146 DESCRIPTION 2147 "Limit on number of total number of active subscribers 2148 supported by the NAT instance. An active subscriber is 2149 defined as any subscriber with at least one map entry, 2150 including static mappings. While the number of active 2151 subscribers is at this limit, subsequent packets that would 2152 otherwise trigger first mappings for newly active 2153 subscribers will be dropped and counted in 2154 natv2InstanceSubscriberActiveLimitDrops. The limit is 2155 disabled by setting the value to zero (default value). 2156 DEFVAL { 0 } 2157 ::= { natv2InstanceEntry 26 } 2159 -- Table of counters per upper layer protocol identified by the 2160 -- packet header and supported by the NAT instance 2162 natv2ProtocolTable OBJECT-TYPE 2163 SYNTAX SEQUENCE OF Natv2ProtocolEntry 2164 MAX-ACCESS not-accessible 2165 STATUS current 2166 DESCRIPTION 2167 "Table of protocols with per-protocol counters. Conceptual 2168 rows of the table are indexed by the combination of the NAT 2169 instance number and the IANA-assigned upper layer protocol 2170 number as given by the ProtocolNumber TC and contained in 2171 the packet IP header. It is up to the agent implementation 2172 to determine and operate upon only those upper layer 2173 protocol numbers supported by the NAT instance." 2174 REFERENCE 2175 "RFC yyyy Section 3.3.5." 2176 ::= { natv2MIBInstanceObjects 2 } 2178 natv2ProtocolEntry OBJECT-TYPE 2179 SYNTAX Natv2ProtocolEntry 2180 MAX-ACCESS not-accessible 2181 STATUS current 2182 DESCRIPTION 2183 "Per-protocol counters." 2184 INDEX { natv2ProtocolInstanceIndex, 2185 natv2ProtocolNumber } 2186 ::= { natv2ProtocolTable 1 } 2188 Natv2ProtocolEntry ::= 2189 SEQUENCE { 2190 natv2ProtocolInstanceIndex Natv2InstanceIndex, 2191 natv2ProtocolNumber ProtocolNumber, 2192 -- State 2193 natv2ProtocolPortMapEntries Unsigned32, 2194 -- Statistics. Discontinuity object from instance table reused here. 2195 natv2ProtocolTranslations Counter64, 2196 natv2ProtocolPortMapCreations Counter64, 2197 natv2ProtocolPortMapFailureDrops Counter64 2198 } 2200 natv2ProtocolInstanceIndex OBJECT-TYPE 2201 SYNTAX Natv2InstanceIndex 2202 MAX-ACCESS not-accessible 2203 STATUS current 2204 DESCRIPTION 2205 "NAT instance index. It is up to the implementation to 2206 determine and operate upon only those values that 2207 correspond to in-service NAT instances." 2208 ::= { natv2ProtocolEntry 1 } 2210 natv2ProtocolNumber OBJECT-TYPE 2211 SYNTAX ProtocolNumber 2212 MAX-ACCESS not-accessible 2213 STATUS current 2214 DESCRIPTION 2215 "Counters in this conceptual row apply to packets indicating 2216 the upper layer protocol identified by this object's 2217 value. It is up to the implementation to determine and 2218 operate upon only those values that correspond to protocols 2219 supported by the NAT instance." 2220 REFERENCE 2221 "RFC yyyy Section 3.3.5. 2222 IANA Protocol Numbers, http://www.iana.org/assignments/ 2223 protocol-numbers/protocol-numbers.xhtml#protocol-numbers-1" 2224 ::= { natv2ProtocolEntry 2 } 2226 -- State 2227 natv2ProtocolPortMapEntries OBJECT-TYPE 2228 SYNTAX Unsigned32 2229 MAX-ACCESS read-only 2230 STATUS current 2231 DESCRIPTION 2232 "The current number of entries in the port map table in total 2233 over the whole NAT instance for a given protocol, including 2234 static mappings. A port map entry maps from a given external 2235 realm, address, and port for a given protocol to an internal 2236 realm, address, and port. This definition includes 'hairpin' 2237 mappings, where the external realm is the same as the 2238 internal one. Port map entries are also tracked per 2239 subscriber, per instance, and per address pool within the 2240 instance." 2241 REFERENCE 2242 "RFC yyyy Section 3.3.5 and Section 3.3.9. Hairpinning: 2243 RFC 4787 Section 6." 2244 ::= { natv2ProtocolEntry 3 } 2246 -- Statistics 2247 natv2ProtocolTranslations OBJECT-TYPE 2248 SYNTAX Counter64 2249 MAX-ACCESS read-only 2250 STATUS current 2251 DESCRIPTION 2252 "The cumulative number of packets translated by the NAT 2253 instance in either direction for the given protocol. 2255 This value MUST be monotone increasing in the periods 2256 between updates of the NAT instance 2257 natv2InstanceDiscontinuityTime. If a manager detects a 2258 change in the latter since the last time it sampled this 2259 counter, it SHOULD NOT make use of the difference between 2260 the latest value of the counter and any value retrieved 2261 before the new value of natv2InstanceDiscontinuityTime." 2262 ::= { natv2ProtocolEntry 4 } 2264 natv2ProtocolPortMapCreations OBJECT-TYPE 2265 SYNTAX Counter64 2266 MAX-ACCESS read-only 2267 STATUS current 2268 DESCRIPTION 2269 "The cumulative number of port map entries created by the NAT 2270 instance for the given protocol. 2272 This value MUST be monotone increasing in the periods 2273 between updates of the NAT instance 2274 natv2InstanceDiscontinuityTime. If a manager detects a 2275 change in the latter since the last time it sampled this 2276 counter, it SHOULD NOT make use of the difference between 2277 the latest value of the counter and any value retrieved 2278 before the new value of natv2InstanceDiscontinuityTime." 2279 ::= { natv2ProtocolEntry 5 } 2281 natv2ProtocolPortMapFailureDrops OBJECT-TYPE 2282 SYNTAX Counter64 2283 MAX-ACCESS read-only 2284 STATUS current 2285 DESCRIPTION 2286 "The cumulative number of packets dropped because the packet 2287 would have triggered the creation of a new port map entry, 2288 but no port could be allocated for the protocol concerned. 2289 The usual case for this will be for a NAT instance that 2290 supports address pooling and the 'paired' pooling behavior 2291 recommended by RFC 4787, where the internal endpoint has 2292 used up all of the ports allocated to it for the address it 2293 was mapped to in the selected address pool in the external 2294 realm concerned and cannot be given more ports because 2295 - policy or implementation prevents it from having a 2296 second address in the same pool, and 2297 - policy or unavailability prevents it from acquiring 2298 more ports at its originally assigned address. 2300 If the NAT instance supports address pooling but its 2301 pooling behavior is 'arbitrary' (meaning that 2302 the NAT instance can allocate a new port mapping for 2303 the given internal endpoint on any address in the 2304 selected address pool and is not bound to what it has 2305 already mapped for that endpoint), then this counter 2306 is incremented when all ports for the protocol concerned 2307 over the whole of the selected address pool are already 2308 in use. 2310 Finally, if the NAT instance has no configured address 2311 pooling, then this counter is incremented because all 2312 ports for the protocol concerned over the whole of the 2313 NAT instance for the external realm concerned are already 2314 in use. 2316 This value MUST be monotone increasing in the periods 2317 between updates of the NAT instance 2318 natv2InstanceDiscontinuityTime. If a manager detects a 2319 change in the latter since the last time it sampled this 2320 counter, it SHOULD NOT make use of the difference between 2321 the latest value of the counter and any value retrieved 2322 before the new value of natv2InstanceDiscontinuityTime." 2323 REFERENCE 2324 "RFC 4787, end of section 4.1." 2325 ::= { natv2ProtocolEntry 6 } 2327 -- pools 2329 natv2PoolTable OBJECT-TYPE 2330 SYNTAX SEQUENCE OF Natv2PoolEntry 2331 MAX-ACCESS not-accessible 2332 STATUS current 2333 DESCRIPTION 2334 "Table of address pools, applicable only if these are 2335 supported by the NAT instance. An address pool is a set of 2336 addresses and ports in a particular realm, available for 2337 assignment to the 'external' portion of a mapping. Where more 2338 than one pool has been configured for the realm, policy 2339 determines which subscribers and/or services are mapped to 2340 which pool. natv2PoolTable provides basic information, state, 2341 statistics, and two notification thresholds for each pool. 2342 natv2PoolRangeTable is an expansion table for natv2PoolTable 2343 that identifies particular address ranges allocated to the 2344 pool." 2346 REFERENCE 2347 "RFC yyyy Section 3.3.6." 2348 ::= { natv2MIBInstanceObjects 3 } 2350 natv2PoolEntry OBJECT-TYPE 2351 SYNTAX Natv2PoolEntry 2352 MAX-ACCESS not-accessible 2353 STATUS current 2354 DESCRIPTION 2355 "Entry in the table of address pools." 2356 INDEX { natv2PoolInstanceIndex, natv2PoolIndex } 2357 ::= { natv2PoolTable 1 } 2359 Natv2PoolEntry ::= 2360 SEQUENCE { 2361 -- Index 2362 natv2PoolInstanceIndex Natv2InstanceIndex, 2363 natv2PoolIndex Natv2PoolIndex, 2364 -- Configuration 2365 natv2PoolRealm SnmpAdminString, 2366 natv2PoolAddressType InetAddressType, 2367 natv2PoolMinimumPort InetPortNumber, 2368 natv2PoolMaximumPort InetPortNumber, 2369 -- State 2370 natv2PoolAddressMapEntries Unsigned32, 2371 natv2PoolPortMapEntries Unsigned32, 2372 -- Statistics and discontinuity time 2373 natv2PoolAddressMapCreations Counter64, 2374 natv2PoolPortMapCreations Counter64, 2375 natv2PoolAddressMapFailureDrops Counter64, 2376 natv2PoolPortMapFailureDrops Counter64, 2377 natv2PoolDiscontinuityTime TimeStamp, 2378 -- Notification thresholds and objects returned by notifications 2379 natv2PoolThresholdUsageLow Integer32, 2380 natv2PoolThresholdUsageHigh Integer32, 2381 natv2PoolNotifiedPortMapEntries Unsigned32, 2382 natv2PoolNotifiedPortMapProtocol ProtocolNumber, 2383 natv2PoolNotificationInterval Unsigned32 2384 } 2386 natv2PoolInstanceIndex OBJECT-TYPE 2387 SYNTAX Natv2InstanceIndex 2388 MAX-ACCESS not-accessible 2389 STATUS current 2390 DESCRIPTION 2391 "NAT instance index. It is up to the agent implementation 2392 to determine and operate upon only those values that 2393 correspond to in-service NAT instances." 2395 ::= { natv2PoolEntry 1 } 2397 natv2PoolIndex OBJECT-TYPE 2398 SYNTAX Natv2PoolIndex 2399 MAX-ACCESS not-accessible 2400 STATUS current 2401 DESCRIPTION 2402 "Index of an address pool, unique for a given NAT instance. 2403 It is up to the agent implementation to determine and 2404 operate upon only those values that correspond to 2405 provisioned pools." 2406 ::= { natv2PoolEntry 2 } 2408 -- configuration 2409 natv2PoolRealm OBJECT-TYPE 2410 SYNTAX SnmpAdminString (SIZE (0..32)) 2411 MAX-ACCESS read-only 2412 STATUS current 2413 DESCRIPTION 2414 "Address realm to which this pool's addresses belong." 2415 REFERENCE 2416 "Address realms are discussed in Section 3.3.3 of 2417 RFC yyyy. Primary reference is RFC 2663 Section 2.1." 2418 ::= { natv2PoolEntry 3 } 2420 natv2PoolAddressType OBJECT-TYPE 2421 SYNTAX InetAddressType 2422 MAX-ACCESS read-create 2423 STATUS current 2424 DESCRIPTION 2425 "Address type supplied by this address pool. This will be the 2426 same for all pools in a given realm (by definition of an 2427 address realm). Values other than ipv4(1) or ipv6(2) would 2428 be unexpected." 2429 REFERENCE 2430 "InetAddressType in RFC 4001." 2431 ::= { natv2PoolEntry 4 } 2433 natv2PoolMinimumPort OBJECT-TYPE 2434 SYNTAX InetPortNumber 2435 MAX-ACCESS read-create 2436 STATUS current 2437 DESCRIPTION 2438 "Minimum port number of the range that can be allocated in 2439 this pool. Applies to all protocols supported by the NAT 2440 instance." 2441 REFERENCE 2442 "InetPortNumber in RFC 4001." 2444 ::= { natv2PoolEntry 5 } 2446 natv2PoolMaximumPort OBJECT-TYPE 2447 SYNTAX InetPortNumber 2448 MAX-ACCESS read-create 2449 STATUS current 2450 DESCRIPTION 2451 "Maximum port number of the range that can be allocated in 2452 this pool. Applies to all protocols supported by the NAT 2453 instance." 2454 REFERENCE 2455 "InetPortNumber in RFC 4001." 2456 ::= { natv2PoolEntry 6 } 2458 -- State 2459 natv2PoolAddressMapEntries OBJECT-TYPE 2460 SYNTAX Unsigned32 2461 MAX-ACCESS read-only 2462 STATUS current 2463 "The current number of address map entries using external 2464 addresses drawn from this pool, including static mappings. 2465 This definition includes 'hairpin' mappings, where the 2466 external realm is the same as the internal one. Address map 2467 entries are also tracked per subscriber and per instance." 2468 REFERENCE 2469 "RFC yyyy Section 3.3.8. Hairpinning: RFC 4787 section 6." 2470 ::= { natv2PoolEntry 7 } 2472 natv2PoolPortMapEntries OBJECT-TYPE 2473 SYNTAX Unsigned32 2474 MAX-ACCESS read-only 2475 STATUS current 2476 DESCRIPTION 2477 "The current number of entries in the port map table using 2478 external addresses and ports drawn from this pool, including 2479 static mappings. This definition includes 'hairpin' 2480 mappings, where the external realm is the same as the 2481 internal one. Port map entries are also tracked per 2482 subscriber, per instance, and per protocol within the 2483 instance." 2484 REFERENCE 2485 "RFC yyyy Section 3.3.9. Hairpinning: RFC 4787 Section 6." 2486 ::= { natv2PoolEntry 8 } 2488 -- Statistics and discontinuity time 2489 natv2PoolAddressMapCreations OBJECT-TYPE 2490 SYNTAX Counter64 2491 MAX-ACCESS read-only 2492 STATUS current 2493 DESCRIPTION 2494 "The cumulative number of address map entries created in this 2495 pool, including static mappings. Address map entries are 2496 also tracked per instance and per subscriber. 2498 This value MUST be monotone increasing in 2499 the periods between updates of the entity's 2500 natv2PoolDiscontinuityTime. If a manager detects a 2501 change in the latter since the last time it sampled this 2502 counter, it SHOULD NOT make use of the difference between 2503 the latest value of the counter and any value retrieved 2504 before the new value of natv2PoolDiscontinuityTime." 2505 ::= { natv2PoolEntry 9 } 2507 natv2PoolPortMapCreations OBJECT-TYPE 2508 SYNTAX Counter64 2509 MAX-ACCESS read-only 2510 STATUS current 2511 DESCRIPTION 2512 "The cumulative number of port map entries created in this 2513 pool, including static mappings. Port map entries are also 2514 tracked per instance, per protocol, and per subscriber. 2516 This value MUST be monotone increasing in the periods 2517 between updates of the entity's 2518 natv2PoolDiscontinuityTime. If a manager detects a 2519 change in the latter since the last time it sampled this 2520 counter, it SHOULD NOT make use of the difference between 2521 the latest value of the counter and any value retrieved 2522 before the new value of natv2PoolDiscontinuityTime." 2523 ::= { natv2PoolEntry 10 } 2525 natv2PoolAddressMapFailureDrops OBJECT-TYPE 2526 SYNTAX Counter64 2527 MAX-ACCESS read-only 2528 STATUS current 2529 DESCRIPTION 2530 "The cumulative number of packets originated by the 2531 subscriber that were dropped because the packet would have 2532 triggered the creation of a new address map entry, but no 2533 address could be allocated from this address pool because 2534 all addresses in the pool have already been fully allocated. 2535 Counters of this event are also provided per instance, per 2536 protocol and per subscriber. 2538 This value MUST be monotone increasing in the periods 2539 between updates of the entity's 2540 natv2PoolDiscontinuityTime. If a manager detects a 2541 change in the latter since the last time it sampled this 2542 counter, it SHOULD NOT make use of the difference between 2543 the latest value of the counter and any value retrieved 2544 before the new value of natv2PoolDiscontinuityTime." 2545 ::= { natv2PoolEntry 11 } 2547 natv2PoolPortMapFailureDrops OBJECT-TYPE 2548 SYNTAX Counter64 2549 MAX-ACCESS read-only 2550 STATUS current 2551 DESCRIPTION 2552 "The cumulative number of packets dropped because the packet 2553 would have triggered the creation of a new port map entry, 2554 but no port could be allocated for the protocol concerned. 2555 The usual case for this will be for a NAT instance that 2556 supports the 'paired' pooling behavior recommended by RFC 2557 4787, where the internal endpoint has used up all of the 2558 ports allocated to it for the address it was mapped to in 2559 this pool and cannot be given more ports because 2560 - policy or implementation prevents it from having a 2561 second address in the same pool, and 2562 - policy or unavailability prevents it from acquiring 2563 more ports at its originally assigned address. 2565 If the NAT instance pooling behavior is 'arbitrary' (meaning 2566 that the NAT instance can allocate a new port mapping for 2567 the given internal endpoint on any address in the selected 2568 address pool and is not bound to what it has already mapped 2569 for that endpoint), then this counter is incremented when 2570 all ports for the protocol concerned over the whole of this 2571 address pool are already in use. 2573 This value MUST be monotone increasing in the periods 2574 between updates of the entity's 2575 natv2PoolDiscontinuityTime. If a manager detects a 2576 change in the latter since the last time it sampled this 2577 counter, it SHOULD NOT make use of the difference between 2578 the latest value of the counter and any value retrieved 2579 before the new value of natv2PoolDiscontinuityTime." 2580 REFERENCE 2581 "Pooling behavior: RFC 4787, end of section 4.1." 2582 ::= { natv2PoolEntry 12 } 2584 natv2PoolDiscontinuityTime OBJECT-TYPE 2585 SYNTAX TimeStamp 2586 MAX-ACCESS read-only 2587 STATUS current 2588 DESCRIPTION 2589 "Snapshot of the value of the sysUpTime object at the 2590 beginning of the latest period of continuity of the 2591 statistical counters associated with this address 2592 pool. This MUST be initialized when the address pool 2593 is configured and MUST be updated whenever the port 2594 or address ranges allocated to the pool change." 2595 ::= { natv2PoolEntry 14 } 2597 -- Notification thresholds and objects returned by notifications 2598 natv2PoolThresholdUsageLow OBJECT-TYPE 2599 SYNTAX Integer32 (-1|0..100) 2600 UNITS "Percent" 2601 MAX-ACCESS read-write 2602 STATUS current 2603 DESCRIPTION 2604 "Threshold for reporting low utilization of the address pool. 2605 Utilization at a given instant is calculated as the 2606 percentage of ports allocated in port map entries for the 2607 most-used protocol at that instant. If utilization is less 2608 than or equal to natv2PoolThresholdUsageLow, an instance of 2609 natv2NotificationPoolUsageLow may be triggered, unless 2610 disabled by setting it to -1. Note the difference from the 2611 disabling setting for other notifications. Reporting is 2612 subject to the per-pool notification interval given by 2613 natv2PoolNotificationInterval. If multiple notifications are 2614 triggered during one interval, the agent MUST report only 2615 the one with the lowest value of 2616 natv2PoolNotifiedPortMapEntries and discard the others. 2618 Implementation note: the percentage specified by this object 2619 can be converted to a number of port map entries at 2620 configuration time (after port and address ranges have been 2621 configured or reconfigured) and compared to the current 2622 value of natv2PoolNotifiedPortMapEntries." 2623 REFERENCE 2624 "RFC yyyy Section 3.1.2 and Section 3.3.6." 2625 DEFVAL { -1 } 2626 ::= { natv2PoolEntry 15 } 2628 natv2PoolThresholdUsageHigh OBJECT-TYPE 2629 SYNTAX Unsigned32 (0..100) 2630 UNITS "Percent" 2631 MAX-ACCESS read-write 2632 STATUS current 2633 DESCRIPTION 2634 "Threshold for reporting high utilization of the address 2635 pool. Utilization at a given instant is calculated as the 2636 percentage of ports allocated in port map entries for the 2637 most-used protocol at that instant. If utilization is 2638 greater than or equal to natv2PoolThresholdUsageHigh, an 2639 instance of natv2NotificationPoolUsageHigh may be triggered, 2640 unless disabled by setting it to 0. 2642 Reporting is subject to the per-pool notification interval 2643 given by natv2PoolNotificationInterval. If multiple 2644 notifications are triggered during one interval, the agent 2645 MUST report only the one with the highest value of 2646 natv2PoolNotifiedPortMapEntries and discard the others. In 2647 the rare case where both upper and lower thresholds 2648 are crossed in the same interval, the agent MUST report only 2649 the upper threshold notification. 2651 Implementation note: the percentage specified by this object 2652 can be converted to a number of port map entries at 2653 configuration time (after port and address ranges have been 2654 configured or reconfigured) and compared to the current 2655 value of natv2PoolNotifiedPortMapEntries." 2656 DEFVAL { 0 } 2657 ::= { natv2PoolEntry 16 } 2659 natv2PoolNotifiedPortMapEntries OBJECT-TYPE 2660 SYNTAX Unsigned32 2661 MAX-ACCESS accessible-for-notify 2662 STATUS current 2663 DESCRIPTION 2664 "Number of port map entries using addresses and ports from 2665 this address pool for the most-used protocol at a given 2666 instant. One of the objects returned by 2667 natv2NotificationPoolUsageLow and 2668 natv2NotificationPoolUsageHigh." 2669 ::= { natv2PoolEntry 17 } 2671 natv2PoolNotifiedPortMapProtocol OBJECT-TYPE 2672 SYNTAX ProtocolNumber 2673 MAX-ACCESS accessible-for-notify 2674 STATUS current 2675 DESCRIPTION 2676 "The most-used protocol (i.e., with the largest number of 2677 port map entries) mapped into this address pool at a given 2678 instant. One of the objects returned by 2679 natv2NotificationPoolUsageLow and 2680 natv2NotificationPoolUsageHigh." 2681 ::= { natv2PoolEntry 18 } 2683 natv2PoolNotificationInterval OBJECT-TYPE 2684 SYNTAX Unsigned32 (1..3600) 2685 UNITS 2686 "Seconds" 2687 MAX-ACCESS read-write 2688 STATUS current 2689 DESCRIPTION 2690 "Minimum number of seconds (default 20) between successive 2691 notifications for this address pool. Controls the generation 2692 of natv2NotificationPoolUsageLow and 2693 natv2NotificationPoolUsageHigh." 2694 DEFVAL 2695 { 20 } 2696 ::= { natv2PoolEntry 19 } 2698 natv2PoolRangeTable OBJECT-TYPE 2699 SYNTAX SEQUENCE OF Natv2PoolRangeEntry 2700 MAX-ACCESS not-accessible 2701 STATUS current 2702 DESCRIPTION 2703 "This table contains address ranges used by pool entries. 2704 It is an expansion of natv2PoolTable." 2705 REFERENCE 2706 "RFC yyyy ." 2707 ::= { natv2MIBInstanceObjects 4 } 2709 natv2PoolRangeEntry OBJECT-TYPE 2710 SYNTAX Natv2PoolRangeEntry 2711 MAX-ACCESS not-accessible 2712 STATUS current 2713 DESCRIPTION 2714 "NAT pool address range." 2715 INDEX { 2716 natv2PoolRangeInstanceIndex, 2717 natv2PoolRangePoolIndex, 2718 natv2PoolRangeRowIndex 2719 } 2720 ::= { natv2PoolRangeTable 1 } 2722 Natv2PoolRangeEntry ::= 2723 SEQUENCE { 2724 natv2PoolRangeInstanceIndex Natv2InstanceIndex, 2725 natv2PoolRangePoolIndex Natv2PoolIndex, 2726 natv2PoolRangeRowIndex Unsigned32, 2727 natv2PoolRangeBegin InetAddress, 2728 natv2PoolRangeEnd InetAddress 2729 } 2731 natv2PoolRangeInstanceIndex OBJECT-TYPE 2732 SYNTAX Natv2InstanceIndex 2733 MAX-ACCESS not-accessible 2734 STATUS current 2735 DESCRIPTION 2736 "Index of the NAT instance on which the address pool and this 2737 address range are configured. See Natv2InstanceIndex." 2738 ::= { natv2PoolRangeEntry 1 } 2740 natv2PoolRangePoolIndex OBJECT-TYPE 2741 SYNTAX Natv2PoolIndex 2742 MAX-ACCESS not-accessible 2743 STATUS current 2744 DESCRIPTION 2745 "Index of the address pool to which this address range 2746 belongs. See Natv2PoolIndex." 2747 ::= { natv2PoolRangeEntry 2 } 2749 natv2PoolRangeRowIndex OBJECT-TYPE 2750 SYNTAX Unsigned32 2751 MAX-ACCESS not-accessible 2752 STATUS current 2753 DESCRIPTION 2754 "Row index for successive range entries for the same 2755 address pool." 2756 ::= { natv2PoolRangeEntry 3 } 2758 natv2PoolRangeBegin OBJECT-TYPE 2759 SYNTAX InetAddress 2760 MAX-ACCESS read-only 2761 STATUS current 2762 DESCRIPTION 2763 "Lowest address included in this range. The type of address 2764 (IPv4 or IPv6) is given by natv2PoolAddressType 2765 in natv2PoolTable." 2766 ::= { natv2PoolRangeEntry 4 } 2768 natv2PoolRangeEnd OBJECT-TYPE 2769 SYNTAX InetAddress 2770 MAX-ACCESS read-only 2771 STATUS current 2772 DESCRIPTION 2773 "Highest address included in this range. The type of address 2774 (IPv4 or IPv6) is given by natv2PoolAddressType 2775 in natv2PoolTable." 2776 ::= { natv2PoolRangeEntry 5 } 2778 -- indexed mapping tables 2780 -- Address Map Table. Mapped from internal to external address. 2782 natv2AddressMapTable OBJECT-TYPE 2783 SYNTAX SEQUENCE OF Natv2AddressMapEntry 2784 MAX-ACCESS not-accessible 2785 STATUS current 2786 DESCRIPTION 2787 "Table of mappings from internal to external address. By 2788 definition, this is a snapshot of NAT instance state at a 2789 given moment. Indexed by NAT instance, internal realm, and 2790 internal address in that realm. Provides the mapped external 2791 address and, depending on implementation support, identifies 2792 the address pool from which the external address and port 2793 were taken and the index of the subscriber to which the 2794 mapping has been allocated. 2796 In the case of DS-Lite [RFC 6333], the indexing realm and 2797 address are those of the IPv6 encapsulation rather than the 2798 IPv4 inner packet." 2799 REFERENCE 2800 "RFC yyyy Section 3.3.8. DS-Lite: RFC 6333" 2801 ::= { natv2MIBInstanceObjects 5 } 2803 natv2AddressMapEntry OBJECT-TYPE 2804 SYNTAX Natv2AddressMapEntry 2805 MAX-ACCESS not-accessible 2806 STATUS current 2807 DESCRIPTION 2808 "Mapping from internal to external address." 2809 INDEX { natv2AddressMapInstanceIndex, 2810 natv2AddressMapInternalRealm, 2811 natv2AddressMapInternalAddressType, 2812 natv2AddressMapInternalAddress, 2813 natv2AddressMapRowIndex } 2814 ::= { natv2AddressMapTable 1 } 2816 Natv2AddressMapEntry ::= 2817 SEQUENCE { 2818 natv2AddressMapInstanceIndex Natv2InstanceIndex, 2819 natv2AddressMapInternalRealm SnmpAdminString, 2820 natv2AddressMapInternalRealmAddressType InetAddressType, 2821 natv2AddressMapInternalRealmAddress InetAddress, 2822 natv2AddressMapRowIndex Unsigned32, 2823 natv2AddressMapInternalMappedAddressType InetAddressType, 2824 natv2AddressMapInternalMappedAddress InetAddress, 2825 natv2AddressMapExternalRealm SnmpAdminString, 2826 natv2AddressMapExternalAddressType InetAddressType, 2827 natv2AddressMapExternalAddress InetAddress, 2828 natv2AddressMapExternalPoolIndex Natv2PoolIndexOrZero, 2829 natv2AddressMapSubscriberIndex Natv2SubscriberIndexOrZero 2830 } 2832 natv2AddressMapInstanceIndex OBJECT-TYPE 2833 SYNTAX Natv2InstanceIndex 2834 MAX-ACCESS not-accessible 2835 STATUS current 2836 DESCRIPTION 2837 "Index of the NAT instance that generated this address map." 2838 ::= { natv2AddressMapEntry 1 } 2840 natv2AddressMapInternalRealm OBJECT-TYPE 2841 SYNTAX SnmpAdminString (SIZE(0..32)) 2842 MAX-ACCESS not-accessible 2843 STATUS current 2844 DESCRIPTION 2845 "Realm to which the internal address belongs. In most cases 2846 this is the realm defining the address space of the packet 2847 being translated. However, in the case of DS-Lite [RFC 2848 6333], this realm defines the IPv6 outer header address 2849 space. It is the combination of that outer header and 2850 the inner IPv4 packet header that is remapped to the 2851 external address and realm. The corresponding IPv4 realm is 2852 restricted in scope to the tunnel, so there is no point in 2853 identifying it. The mapped IPv4 address will normally be the 2854 well-known value 192.0.0.2, or at least lie in the reserved 2855 192.0.0.0/29 range. 2857 If natv2AddressMapSubscriberIndex in this table is a valid 2858 subscriber index (i.e., greater than zero), then the value 2859 of natv2AddressMapInternalRealm MUST be identical to the 2860 value of natv2SubscriberRealm associated with that index." 2861 REFERENCE 2862 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 2863 Section 6.6 on the need to have the IPv6 tunnel address in 2864 the NAT mapping tables." 2865 ::= { natv2AddressMapEntry 2 } 2867 natv2AddressMapInternalRealmAddressType OBJECT-TYPE 2868 SYNTAX InetAddressType 2869 MAX-ACCESS read-only 2870 STATUS current 2871 DESCRIPTION 2872 "Address type in the header of packets on the 2873 interior side of this mapping. Any value other than ipv4(1) 2874 or ipv6(2) would be unexpected. 2876 In the DS-Lite case, the address type is ipv6(2)." 2877 REFERENCE 2878 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 2879 Section 6.6 on the need to have the IPv6 tunnel source 2880 address in the NAT mapping tables." 2881 ::= { natv2AddressMapEntry 3 } 2883 natv2AddressMapInternalRealmAddress OBJECT-TYPE 2884 SYNTAX InetAddress 2885 MAX-ACCESS read-only 2886 STATUS current 2887 DESCRIPTION 2888 "Source address of packets originating from the interior 2889 of the association provided by this mapping. 2891 In the case of DS-Lite [RFC 6333], this is the IPv6 tunnel 2892 source address. The mapping in this case is considered to 2893 be from the combination of the IPv6 tunnel source address 2894 natv2AddressMapInternalRealmAddress and the well-known IPv4 2895 inner source address natv2AddressMapInternalMappedAddress to 2896 the external address." 2897 REFERENCE 2898 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 2899 Section 6.6 on the need to have the IPv6 tunnel address in 2900 the NAT mapping tables." 2901 ::= { natv2AddressMapEntry 4 } 2903 natv2AddressMapRowIndex OBJECT-TYPE 2904 SYNTAX Unsigned32 2905 MAX-ACCESS not-accessible 2906 STATUS current 2907 DESCRIPTION 2908 "Index of a conceptual row corresponding to a mapping of the 2909 given internal realm and address to a single external realm 2910 and address. Multiple rows will be present because of a 2911 promiscuous external address selection policy, policies 2912 associating the same internal address with different address 2913 pools, or because the same internal realm-address 2914 combination is communicating with multiple external address 2915 realms." 2916 ::= { natv2AddressMapEntry 5 } 2918 natv2AddressMapInternalMappedAddressType OBJECT-TYPE 2919 SYNTAX InetAddressType 2920 MAX-ACCESS read-only 2921 STATUS current 2922 DESCRIPTION 2923 "Internal address type actually translated by this mapping. 2924 Any value other than ipv4(1) or ipv6(2) would be unexpected. 2925 In the general case, this is the same as given by 2926 natv2AddressMapInternalRealmAddressType. In the 2927 tunneled case it is the address type used in the 2928 encapsulated packet header. In particular, in the DS-Lite 2929 case, the mapped address type is ipv4(1)." 2930 REFERENCE 2931 "DS-Lite: RFC 6333." 2932 ::= { natv2AddressMapEntry 6 } 2934 natv2AddressMapInternalMappedAddress OBJECT-TYPE 2935 SYNTAX InetAddress 2936 MAX-ACCESS read-only 2937 STATUS current 2938 DESCRIPTION 2939 "Internal address actually translated by this mapping. In the 2940 general case, this is the same as 2941 natv2AddressMapInternalRealmAddress. In the case of DS-Lite 2942 [RFC 6333], this is the source address of the encapsulated 2943 IPv4 packet, normally lying the well-known range 2944 192.0.0.0/29. The mapping in this case is considered to be 2945 from the combination of the IPv6 tunnel source address 2946 natv2AddressMapInternalRealmAddress and the well-known IPv4 2947 inner source address natv2AddressMapInternalMappedAddress to 2948 the external address." 2949 REFERENCE 2950 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 2951 Section 6.6 on the need to have the IPv6 tunnel address in 2952 the NAT mapping tables." 2953 ::= { natv2AddressMapEntry 7 } 2955 natv2AddressMapExternalRealm OBJECT-TYPE 2956 SYNTAX SnmpAdminString (SIZE(0..32)) 2957 MAX-ACCESS read-only 2958 STATUS current 2959 DESCRIPTION 2960 "External address realm to which this mapping maps the 2961 internal address. This can be the same as the internal realm 2962 in the case of a 'hairpin' connection, but otherwise will be 2963 different." 2964 ::= { natv2AddressMapEntry 8 } 2966 natv2AddressMapExternalAddressType OBJECT-TYPE 2967 SYNTAX InetAddressType 2968 MAX-ACCESS read-only 2969 STATUS current 2970 DESCRIPTION 2971 "Address type for the external realm. Any value other than 2972 ipv4(1) or ipv6(2) would be unexpected." 2973 ::= { natv2AddressMapEntry 9 } 2975 natv2AddressMapExternalAddress OBJECT-TYPE 2976 SYNTAX InetAddress 2977 MAX-ACCESS read-only 2978 STATUS current 2979 DESCRIPTION 2980 "External address to which the internal address is mapped. 2982 In the DS-Lite case, the mapping is from the combination of 2983 the internal IPv6 tunnel source address as presented in this 2984 table and the well-known IPv4 source address of the 2985 encapsulated IPv4 packet." 2986 REFERENCE 2987 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 2988 Section 6.6 on the need to have the IPv6 tunnel address in 2989 the NAT mapping tables." 2990 ::= { natv2AddressMapEntry 10 } 2992 natv2AddressMapExternalPoolIndex OBJECT-TYPE 2993 SYNTAX Natv2PoolIndexOrZero 2994 MAX-ACCESS read-only 2995 STATUS current 2996 DESCRIPTION 2997 "Index of the address pool in the external realm from which 2998 the mapped external address given in 2999 natv2AddressMapExternalAddress was taken. Zero if the 3000 implementation does not support address pools but has chosen 3001 to support this object, or if no pool was configured for the 3002 given external realm." 3003 ::= { natv2AddressMapEntry 11 } 3005 natv2AddressMapSubscriberIndex OBJECT-TYPE 3006 SYNTAX Natv2SubscriberIndexOrZero 3007 MAX-ACCESS read-only 3008 STATUS current 3009 DESCRIPTION 3010 "Index of the subscriber to which this address mapping 3011 applies, or zero if no subscribers are configured on 3012 this NAT instance." 3013 ::= { natv2AddressMapEntry 12 } 3015 -- natv2PortMapTable 3016 natv2PortMapTable OBJECT-TYPE 3017 SYNTAX SEQUENCE OF Natv2PortMapEntry 3018 MAX-ACCESS not-accessible 3019 STATUS current 3020 DESCRIPTION 3021 "Table of port map entries indexed by NAT instance, protocol, 3022 and external realm and address. A port map entry associates 3023 an internal upper layer protocol endpoint with an endpoint 3024 for the same protocol in the given external realm. By 3025 definition, this is a snapshot of NAT instance state at a 3026 given moment. The table provides the basic mapping 3027 information. 3029 In the case of DS-Lite [RFC 6333], the table provides the 3030 internal IPv6 tunnel source address in 3031 natv2PortMapInternalRealmAddress and the IPv4 source address 3032 of the encapsulated packet that is actually translated in 3033 natv2PortMapInternalMappedAddress. In the general (non-DS- 3034 Lite) case, those two objects will have the same value." 3035 REFERENCE 3036 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 3037 Section 6.6 on the need to have the IPv6 tunnel address in 3038 the NAT mapping tables." 3039 REFERENCE 3040 "RFC yyyy Section 3.3.9 3041 ::= { natv2MIBInstanceObjects 6 } 3043 natv2PortMapEntry OBJECT-TYPE 3044 SYNTAX Natv2PortMapEntry 3045 MAX-ACCESS not-accessible 3046 STATUS current 3047 DESCRIPTION 3048 "A single NAT mapping." 3049 INDEX { natv2PortMapInstanceIndex, 3050 natv2PortMapProtocol, 3051 natv2PortMapExternalRealm, 3052 natv2PortMapExternalAddressType, 3053 natv2PortMapExternalAddress, 3054 natv2PortMapExternalPort } 3055 ::= { natv2PortMapTable 1 } 3057 Natv2PortMapEntry ::= 3058 SEQUENCE { 3059 natv2PortMapInstanceIndex Natv2InstanceIndex, 3060 natv2PortMapProtocol ProtocolNumber, 3061 natv2PortMapExternalRealm SnmpAdminString, 3062 natv2PortMapExternalAddressType InetAddressType, 3063 natv2PortMapExternalAddress InetAddress, 3064 natv2PortMapExternalPort InetPortNumber, 3065 natv2PortMapInternalRealm SnmpAdminString, 3066 natv2PortMapInternalRealmAddressType InetAddressType, 3067 natv2PortMapInternalRealmAddress InetAddress, 3068 natv2PortMapInternalMappedAddressType InetAddressType, 3069 natv2PortMapInternalMappedAddress InetAddress, 3070 natv2PortMapInternalPort InetPortNumber, 3071 natv2PortMapExternalPool Natv2PoolIndexOrZero, 3072 natv2PortMapSubscriberIndex Natv2SubscriberIndexOrZero 3073 } 3075 natv2PortMapInstanceIndex OBJECT-TYPE 3076 SYNTAX Natv2InstanceIndex 3077 MAX-ACCESS not-accessible 3078 STATUS current 3079 DESCRIPTION 3080 "Index of the NAT instance that created this port map entry." 3081 ::= { natv2PortMapEntry 1 } 3083 natv2PortMapProtocol OBJECT-TYPE 3084 SYNTAX ProtocolNumber 3085 MAX-ACCESS not-accessible 3086 STATUS current 3087 DESCRIPTION 3088 "The map entry's upper layer protocol number." 3089 ::= { natv2PortMapEntry 2 } 3091 natv2PortMapExternalRealm OBJECT-TYPE 3092 SYNTAX SnmpAdminString (SIZE(0..32)) 3093 MAX-ACCESS not-accessible 3094 STATUS current 3095 DESCRIPTION 3096 "The realm to which natv2PortMapExternalAddress belongs." 3097 ::= { natv2PortMapEntry 3 } 3099 natv2PortMapExternalAddressType OBJECT-TYPE 3100 SYNTAX InetAddressType 3101 MAX-ACCESS not-accessible 3102 STATUS current 3103 DESCRIPTION 3104 "Address type for the external realm. A value other 3105 than ipv4(1) or ipv6(2) would be unexpected." 3106 ::= { natv2PortMapEntry 4 } 3108 natv2PortMapExternalAddress OBJECT-TYPE 3109 SYNTAX InetAddress 3110 MAX-ACCESS not-accessible 3111 STATUS current 3112 DESCRIPTION 3113 "The mapping's assigned external address. (This address is 3114 taken from the address pool identified by 3115 natv2PortMapExternalPoolIndex, if the implementation 3116 supports address pools and pools are configured for the 3117 given external realm.) This is the source address for 3118 translated outgoing packets." 3120 ::= { natv2PortMapEntry 5 } 3122 natv2PortMapExternalPort OBJECT-TYPE 3123 SYNTAX InetPortNumber 3124 MAX-ACCESS not-accessible 3125 STATUS current 3126 DESCRIPTION 3127 "The mapping's assigned external port number. This is the 3128 source port for translated outgoing packets. If the internal 3129 port number given by natv2PortMapInternalPort is zero this 3130 value MUST also be zero. Otherwise this MUST be a non-zero 3131 value." 3132 ::= { natv2PortMapEntry 6 } 3134 natv2PortMapInternalRealm OBJECT-TYPE 3135 SYNTAX SnmpAdminString (SIZE(0..32)) 3136 MAX-ACCESS read-only 3137 STATUS current 3138 DESCRIPTION 3139 "The realm to which natv2PortMapInternalRealmAddress belongs. 3140 In the general case, this realm contains the address that is 3141 being translated. In the DS-Lite [RFC 6333] case, this realm 3142 defines the IPv6 address space from which the tunnel source 3143 address is taken. The realm of the encapsulated IPv4 address 3144 is restricted in scope to the tunnel, so there is no point 3145 in identifying it separately." 3146 REFERENCE 3147 "RFC 6333 DS-Lite." 3148 ::= { natv2PortMapEntry 7 } 3150 natv2PortMapInternalRealmAddressType OBJECT-TYPE 3151 SYNTAX InetAddressType 3152 MAX-ACCESS read-only 3153 STATUS current 3154 DESCRIPTION 3155 "Address type for addresses in the realm identified by 3156 natv2PortMapInternalRealm." 3157 ::= { natv2PortMapEntry 8 } 3159 natv2PortMapInternalRealmAddress OBJECT-TYPE 3160 SYNTAX InetAddress 3161 MAX-ACCESS read-only 3162 STATUS current 3163 DESCRIPTION 3164 "Source address for packets received under this mapping on 3165 the internal side of the NAT instance. In the general case 3166 this address is the same as the address given in 3167 natv2PortMapInternalMappedAddress. In the DS-Lite case, 3168 natv2PortMapInternalRealmAddress is the IPv6 tunnel source 3169 address." 3170 REFERENCE 3171 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 3172 Section 6.6 on the need to have the IPv6 tunnel address in 3173 the NAT mapping tables." 3174 ::= { natv2PortMapEntry 9 } 3176 natv2PortMapInternalMappedAddressType OBJECT-TYPE 3177 SYNTAX InetAddressType 3178 MAX-ACCESS read-only 3179 STATUS current 3180 DESCRIPTION 3181 "Internal address type actually translated by this mapping. 3182 Any value other than ipv4(1) or ipv6(2) would be unexpected. 3183 In the general case, this is the same as given by 3184 natv2AddressMapInternalRealmAddressType. In the DS-Lite 3185 case, the address type is ipv4(1)." 3186 REFERENCE 3187 "DS-Lite: RFC 6333." 3188 ::= { natv2PortMapEntry 10 } 3190 natv2PortMapInternalMappedAddress OBJECT-TYPE 3191 SYNTAX InetAddress 3192 MAX-ACCESS read-only 3193 STATUS current 3194 DESCRIPTION 3195 "Internal address actually translated by this mapping. In the 3196 general case, this is the same as 3197 natv2PortMapInternalRealmAddress. In the case of DS-Lite 3198 [RFC 6333], this is the source address of the encapsulated 3199 IPv4 packet, normally selected from the well-known range 3200 192.0.0.0/29. The mapping in this case is considered to be 3201 from the external address to the combination of the IPv6 3202 tunnel source address natv2PortMapInternalRealmAddress and 3203 the well-known IPv4 inner source address 3204 natv2PortMapInternalMappedAddress." 3205 REFERENCE 3206 "DS-Lite: RFC 6333, Section 5.7 for well-known addresses and 3207 Section 6.6 on the need to have the IPv6 tunnel address in 3208 the NAT mapping tables." 3209 ::= { natv2PortMapEntry 11 } 3211 natv2PortMapInternalPort OBJECT-TYPE 3212 SYNTAX InetPortNumber 3213 MAX-ACCESS read-only 3214 STATUS current 3215 DESCRIPTION 3216 "The mapping's internal port number. If this is zero, ports 3217 are not translated (i.e., the NAT instance is a pure NAT 3218 rather than a NAPT)." 3219 ::= { natv2PortMapEntry 12 } 3221 natv2PortMapExternalPoolIndex OBJECT-TYPE 3222 SYNTAX Natv2PoolIndexOrZero 3223 MAX-ACCESS read-only 3224 STATUS current 3225 DESCRIPTION 3226 "Identifies the address pool from which the external address 3227 in this port map entry was taken. Zero if the implementation 3228 does not support address pools but has chosen to support 3229 this object, or if no pools are configured for the given 3230 external realm." 3232 natv2PortMapSubscriberIndex OBJECT-TYPE 3233 SYNTAX Natv2SubscriberIndexOrZero 3234 MAX-ACCESS read-only 3235 STATUS current 3236 DESCRIPTION 3237 "Subscriber using this map entry. Zero if the implementation 3238 does not support subscribers but has chosen to support 3239 this object." 3240 ::= { natv2PortMapEntry 13 } 3242 -- Conformance section. Specifies three cumulatively more extensive 3243 -- applications: basic NAT, pooled NAT, and carrier grade NAT 3245 natv2MIBConformance OBJECT IDENTIFIER ::= { natv2MIB 3 } 3247 natv2MIBCompliances OBJECT IDENTIFIER ::= { natv2MIBConformance 1 } 3248 natv2MIBGroups OBJECT IDENTIFIER ::= { natv2MIBConformance 2 } 3250 natv2MIBBasicCompliance MODULE-COMPLIANCE 3251 STATUS current 3252 DESCRIPTION 3253 "Describes the requirements for conformance to the basic NAT 3254 application of NATv2 MIB." 3255 MODULE -- this module 3256 MANDATORY-GROUPS { natv2BasicNotificationGroup, 3257 natv2BasicInstanceLevelGroup 3258 } 3259 GROUP natv2BasicNotificationGroup 3260 DESCRIPTION 3261 "The natv2BasicNotificationGroup is mandatory for all 3262 NAT applications." 3263 GROUP natv2BasicInstanceLevelGroup 3264 DESCRIPTION 3265 "The natv2BasicInstanceLevelGroup is mandatory for all 3266 NAT applications." 3267 ::= { natv2MIBCompliances 1 } 3269 natv2MIBPooledNATCompliance MODULE-COMPLIANCE 3270 STATUS current 3271 DESCRIPTION 3272 "Describes the requirements for conformance to the pooled NAT 3273 application of NATv2-MIB." 3274 MODULE -- this module 3275 MANDATORY-GROUPS { natv2BasicNotificationGroup, 3276 natv2BasicInstanceLevelGroup, 3277 natv2PooledNotificationGroup, 3278 natv2PooledInstanceLevelGroup 3279 } 3280 GROUP natv2BasicNotificationGroup 3281 DESCRIPTION 3282 "The natv2BasicNotificationGroup is mandatory for all 3283 NAT applications." 3284 GROUP natv2BasicInstanceLevelGroup 3285 DESCRIPTION 3286 "The natv2BasicInstanceLevelGroup is mandatory for all 3287 NAT applications." 3288 GROUP natv2PooledNotificationGroup 3289 DESCRIPTION 3290 "The natv2PooledNotificationGroup is mandatory for 3291 the pooled and CGN applications." 3292 GROUP natv2PooledInstanceLevelGroup 3293 DESCRIPTION 3294 "The natv2PooledInstanceLevelGroup is mandatory for 3295 the pooled and CGN applications." 3296 ::= { natv2MIBCompliances 2 } 3298 natv2MIBCGNCompliance MODULE-COMPLIANCE 3299 STATUS current 3300 DESCRIPTION 3301 "Describes the requirements for conformance to the 3302 carrier grade NAT application of NATv2-MIB." 3303 MODULE -- this module 3304 MANDATORY-GROUPS { natv2BasicNotificationGroup, 3305 natv2BasicInstanceLevelGroup, 3306 natv2PooledNotificationGroup, 3307 natv2PooledInstanceLevelGroup, 3308 natv2CGNNotificationGroup, 3309 natv2CGNDeviceLevelGroup, 3310 natv2CGNInstanceLevelGroup 3311 } 3312 GROUP natv2BasicNotificationGroup 3313 DESCRIPTION 3314 "The natv2BasicNotificationGroup is mandatory for all 3315 NAT applications." 3316 GROUP natv2BasicInstanceLevelGroup 3317 DESCRIPTION 3318 "The natv2BasicInstanceLevelGroup is mandatory for all 3319 NAT applications." 3320 GROUP natv2PooledNotificationGroup 3321 DESCRIPTION 3322 "The natv2PooledNotificationGroup is mandatory for 3323 the pooled and CGN applications." 3324 GROUP natv2PooledInstanceLevelGroup 3325 DESCRIPTION 3326 "The natv2PooledInstanceLevelGroup is mandatory for 3327 the pooled and CGN applications." 3328 GROUP natv2CGNNotificationGroup 3329 DESCRIPTION 3330 "The natv2CGNNotificationGroup is mandatory 3331 for the carrier grade NAT application." 3332 GROUP natv2CGNDeviceLevelGroup 3333 DESCRIPTION 3334 "The natv2CGNDeviceLevelGroup is mandatory 3335 for the carrier grade NAT application." 3336 GROUP natv2CGNInstanceLevelGroup 3337 DESCRIPTION 3338 "The natv2CGNInstanceLevelGroup is mandatory 3339 for the carrier grade NAT application." 3340 ::= { natv2MIBCompliances 3 } 3342 -- Groups 3344 natv2BasicNotificationGroup NOTIFICATION-GROUP 3345 NOTIFICATIONS { 3346 natv2NotificationInstanceAddressMapEntriesHigh, 3347 natv2NotificationInstancePortMapEntriesHigh 3348 } 3349 STATUS current 3350 DESCRIPTION 3351 "Notifications that MUST be supported by all NAT 3352 applications." 3353 ::= { natv2MIBGroups 1 } 3355 natv2BasicInstanceLevelGroup OBJECT-GROUP 3356 OBJECTS { 3357 -- from natv2InstanceTable 3358 natv2InstanceIndex, 3359 natv2InstanceAlias, 3360 natv2InstancePortMappingBehavior, 3361 natv2InstanceFilteringBehavior, 3362 natv2InstanceFragmentBehavior, 3363 natv2InstanceAddressMapEntries, 3364 natv2InstancePortMapEntries, 3365 natv2InstanceTranslations, 3366 natv2InstanceAddressMapCreations, 3367 natv2InstanceAddressMapEntryLimitDrops, 3368 natv2InstanceAddressMapFailureDrops, 3369 natv2InstancePortMapCreations, 3370 natv2InstancePortMapEntryLimitDrops, 3371 natv2InstancePortMapFailureDrops, 3372 natv2InstanceFragmentDrops, 3373 natv2InstanceOtherResourceFailureDrops, 3374 natv2InstanceDiscontinuityTime, 3375 natv2InstanceThresholdAddressMapEntriesHigh, 3376 natv2InstanceThresholdPortMapEntriesHigh, 3377 natv2InstanceNotificationInterval, 3378 natv2InstanceLimitAddressMapEntries, 3379 natv2InstanceLimitPortMapEntries, 3380 natv2InstanceLimitPendingFragments, 3381 -- from natv2ProtocolTable 3382 natv2ProtocolInstanceIndex, 3383 natv2ProtocolNumber, 3384 natv2ProtocolPortMapEntries, 3385 natv2ProtocolTranslations, 3386 natv2ProtocolPortMapCreations, 3387 natv2ProtocolPortMapFailureDrops, 3388 natv2ProtocolOtherResourceFailureDrops, 3389 -- from natv2AddressMapTable 3390 natv2AddressMapInstanceIndex, 3391 natv2AddressMapInternalRealm, 3392 natv2AddressMapInternalRealmAddressType, 3393 natv2AddressMapInternalRealmAddress, 3394 natv2AddressMapRowIndex, 3395 natv2AddressMapExternalRealm, 3396 natv2AddressMapExternalAddressType, 3397 natv2AddressMapExternalAddress, 3398 -- from natv2PortMapTable 3399 natv2PortMapInstanceIndex, 3400 natv2PortMapProtocol, 3401 natv2PortMapExternalRealm, 3402 natv2PortMapExternalAddressType, 3403 natv2PortMapExternalAddress, 3404 natv2PortMapExternalPort, 3405 natv2PortMapInternalRealm, 3406 natv2PortMapInternalRealmAddressType, 3407 natv2PortMapInternalRealmAddress, 3408 natv2PortMapInternalPort 3409 } 3410 STATUS current 3411 DESCRIPTION 3412 "Per-instance objects that MUST be supported by 3413 implementations of all NAT applications." 3414 ::= { natv2MIBGroups 2 } 3416 natv2PooledNotificationGroup NOTIFICATION-GROUP 3417 NOTIFICATIONS { 3418 natv2NotificationPoolUsageLow, 3419 natv2NotificationPoolUsageHigh 3420 } 3421 STATUS current 3422 DESCRIPTION 3423 "Notifications that MUST be supported by pooled and 3424 carrier-grade NAT applications." 3425 ::= { natv2MIBGroups 3 } 3427 natv2PooledInstanceLevelGroup OBJECT-GROUP 3428 OBJECTS { 3429 -- from natv2InstanceTable 3430 natv2InstancePoolingBehavior, 3431 -- from natv2PoolTable 3432 natv2PoolInstanceIndex, 3433 natv2PoolIndex, 3434 natv2PoolRealm, 3435 natv2PoolAddressType, 3436 natv2PoolMinimumPort, 3437 natv2PoolMaximumPort, 3438 natv2PoolAddressMapEntries 3439 natv2PoolPortMapEntries 3440 natv2PoolAddressMapCreations, 3441 natv2PoolPortMapCreations 3442 natv2PoolAddressMapFailureDrops, 3443 natv2PoolPortMapFailureDrops 3444 natv2PoolOtherResourceFailureDrops 3445 natv2PoolDiscontinuityTime, 3446 natv2PoolThresholdUsageLow, 3447 natv2PoolThresholdUsageHigh, 3448 natv2PoolNotifiedPortMapEntries, 3449 natv2PoolNotifiedPortMapProtocol, 3450 natv2PoolNotificationInterval, 3451 -- from natv2PoolRangeTable 3452 natv2PoolRangeInstanceIndex, 3453 natv2PoolRangePoolIndex, 3454 natv2PoolRangeRowIndex, 3455 natv2PoolRangeBegin, 3456 natv2PoolRangeEnd, 3457 -- from natv2AddressMapTable 3458 natv2AddressMapExternalPoolIndex, 3459 -- from natv2PortMapTable 3460 natv2PortMapExternalPoolIndex 3461 } 3462 STATUS current 3463 DESCRIPTION 3464 "Per-instance objects that MUST be supported by 3465 implementations of the pooled and carrier grade 3466 NAT applications." 3467 ::= { natv2MIBGroups 4 } 3469 natv2CGNNotificationGroup NOTIFICATION-GROUP 3470 NOTIFICATIONS { 3471 natv2NotificationSubscriberPortMappingEntriesHigh 3472 } 3473 STATUS current 3474 DESCRIPTION 3475 "Notification that MUST be supported by implementations 3476 of the carrier grade NAT application." 3477 ::= { natv2MIBGroups 5 } 3479 natv2CGNDeviceLevelGroup OBJECT-GROUP 3480 OBJECTS { 3481 -- from table natv2SubscriberTable 3482 natv2SubscriberIndex, 3483 natv2SubscriberRealm, 3484 natv2SubscriberInternalPrefixType, 3485 natv2SubscriberInternalPrefix, 3486 natv2SubscriberInternalPrefixLength, 3487 natv2SubscriberAddressMapEntries, 3488 natv2SubscriberPortMapEntries, 3489 natv2SubscriberTranslations, 3490 natv2SubscriberAddressMapCreations, 3491 natv2SubscriberPortMapCreations, 3492 natv2SubscriberAddressMapFailureDrops, 3493 natv2SubscriberPortMapFailureDrops, 3494 natv2SubscriberOtherResourceFailureDrops, 3495 natv2SubscriberDiscontinuityTime, 3496 natv2SubscriberLimitPortMapEntries, 3497 natv2SubscriberThresholdPortMapEntriesHigh, 3498 natv2SubscriberNotificationInterval 3499 } 3500 STATUS current 3501 DESCRIPTION 3502 "Device-level objects that MUST be supported by the 3503 carrier-grade NAT application." 3504 ::= { natv2MIBGroups 6 } 3506 natv2CGNInstanceLevelGroup OBJECT-GROUP 3507 OBJECTS { 3508 -- from natv2InstanceTable 3509 natv2InstanceSubscriberActiveLimitDrops, 3510 natv2InstanceLimitSubscriberActives, 3511 -- from natv2AddressMapTable 3512 natv2AddressMapSubscriberIndex, 3513 -- from natv2PortMapTable 3514 natv2PortMapSubscriberIndex 3515 } 3516 STATUS current 3517 DESCRIPTION 3518 "Per-instance objects that MUST be supported by the 3519 carrier grade NAT application." 3520 ::= { natv2MIBGroups 7 } 3522 END 3524 5. Operational and Management Considerations 3526 This section covers two particular areas of operations and 3527 management: configuration requirements, and transition from or 3528 coexistence with the [RFC4008] MIB module. 3530 5.1. Configuration Requirements 3532 This MIB module assumes that the following information is configured 3533 on the NAT device by means outside the scope of the present document 3534 or is imposed by the implementation: 3536 o the set of address realms to which the device connects; 3538 o For the CGN application, per-subscriber information including 3539 subscriber index, address realm, assigned prefix or address, and 3540 (possibly) policies regarding address pool selection in the 3541 various possible address realms to which the subscriber may 3542 connect. In the particular case of DS-Lite [RFC6333] access, as 3543 well as the assigned outer layer (IPv6) prefix or address, the 3544 subscriber information will include an inner (IPv4) source 3545 address, usually 192.0.0.2. 3547 o the set of NAT instances running on the device, identified by NAT 3548 instance index and name; 3550 o the port mapping, filtering, pooling, and fragment behavior for 3551 each NAT instance; 3553 o the set of protocols supported by each NAT instance; 3555 o for the pooled NAT and CGN applications, address pool information 3556 for each NAT instance, including for each pool the pool index, 3557 address realm, address type, minimum and maximum port number, the 3558 address ranges assigned to that pool, and policies for access to 3559 that pool's resources; 3561 o static address and port map entries. 3563 As described in previous sections, this MIB module does provide read- 3564 write objects for control of notifications (see especially 3565 Section 3.1.2) and limiting of resource consumption (Section 3.1.1). 3566 This document is written in advance of any practical experience with 3567 the setting of these values, and can thus provide only general 3568 principles for how to set them. 3570 By default, the MIB module definition disables notifications until 3571 they are explicitly enabled by the operator, using the associated 3572 threshold value to do so. To make use of the notifications, the 3573 operator may wish to take the following considerations into account. 3575 Except for the low address pool utilization notification, the 3576 notifications imply that some sort of administrative action is 3577 required to mitigate an impending shortage of a particular resource. 3578 The choice of value for the triggering threshold needs to take two 3579 factors into account: the volatility of usage of the given resource, 3580 and the amount of time the operator needs to mitigate the potential 3581 overload situation. That time could vary from almost immediate to 3582 several weeks required to order and install new hardware or software. 3584 To give a numeric example, if average utilization is going up 1% per 3585 week but can vary 10% around that average in any given hour, and it 3586 takes two weeks to carry through mitigating measures, the threshold 3587 should be set to 88% of the corresponding limit (two weeks' growth 3588 plus 10% volatility margin). If mitigating measures can be carried 3589 out immediately, this can rise to 90%. For this particular example 3590 that change is insignificant, but in other cases the difference may 3591 be large enough to matter in terms of reduced load on the management 3592 plane. 3594 The notification rate limit settings really depend on the operator's 3595 processes, but are a tradeoff between reliably reporting the notified 3596 condition and not having it overload the management plane. 3597 Reliability rises in importance with the importance of the resource 3598 involved. Thus the default notification intervals defined in this 3599 MIB module range from 10 seconds (high reliability) for the address 3600 and port map entry thresholds up to 60 seconds (lower reliability) 3601 for the per-subscriber port entry thresholds. Experience may suggest 3602 better values. 3604 The limits on number of instance-level address map and port map 3605 entries and held fragments relate directly to memory allocations for 3606 these tables. The relationship between number of map entries or 3607 number of held fragments and memory required will be implementation- 3608 specific. Hence it is up to the implementor to provide specific 3609 advice on the setting of these limits. 3611 The limit on simultaneous number of active subscribers is indirectly 3612 related to memory consumption for map entries, but also to processor 3613 usage by the NAT instance. The best strategy for setting this limit 3614 would seem to be to leave it disabled during an initial period while 3615 observing device processor utilization, then to implement a trial 3616 setting while observing the number of blocked packets affected by the 3617 new limit. The setting may vary by NAT instance if a suitable 3618 estimator of likely load (e.g., total number of hosts served by that 3619 instance) is available. 3621 5.2. Transition From and Coexistence With NAT-MIB [RFC 4008] 3623 A manager may have to deal with a mixture of devices supporting the 3624 NAT-MIB module [RFC4008] and the NATV2-MIB module defined in the 3625 present document. It is even possible that both modules are 3626 supported on the same device. The following discussion brings out 3627 the limits of comparability between the two MIB modules. A first 3628 point to note is that NAT-MIB is primarily focussed on configuration, 3629 while NATV2-MIB is primarily focussed on measurements. 3631 To summarize the model used by [RFC4008]: 3633 o The basic unit of NAT configuration is the interface. 3635 o An interface connects to a single realm, either "private", or 3636 "public". In principle that means there could be multiple 3637 instances of one type of realm or the other, but the number is 3638 physically limited by the number of interfaces on the NAT device. 3640 o Before the NAT can operate on a given interface, an "address map" 3641 has to be configured on it. The [RFC4008] address map is 3642 equivalent to the pool tables in the present document. Since just 3643 one "address map" is configured per interface, this is the 3644 equivalent of a single address pool per interface. 3646 o The address binding and port binding tables are roughly equivalent 3647 to the address map and port map tables in the present document in 3648 their content, but can be either uni- directional or 3649 bidirectional. The [RFC4008] model shows the address binding and 3650 port binding as alternative precursors to session establishment, 3651 depending on whether the device does address translation only or 3652 address and port translation. In contrast, NATV2-MIB assumes a 3653 model where bidirectional port mappings are based on bidirectional 3654 address mappings that have conceptually been established 3655 beforehand. 3657 o The equivalent to an [RFC4008] session in NATV2-MIB would be a 3658 pair of port map entries. The added complexity in [RFC4008] is 3659 due to the modelling of NAT service types as defined in [RFC3489] 3660 (the symmetric NAT in particular) instead of the more granular set 3661 of behaviors described in [RFC4787]. 3663 With regard to that last point, the mapping between [RFC3489] service 3664 types and [RFC4787] NAT behaviours is as follows: 3666 o A full cone NAT exhibits endpoint-independent port mapping 3667 behavior and endpoint-independent filtering behavior. 3669 o A restricted cone NAT exhibits endpoint-independent port mapping 3670 behavior, but address-dependent filtering behavior. 3672 o A port restricted cone NAT exhibits endpoint-independent port 3673 mapping behavior, but address-and-port-dependent filtering 3674 behavior. 3676 o A symmetric NAT exhibits address-and-port-dependent port mapping 3677 and filtering behaviors. 3679 Note that these NAT types are a subset of the types that could be 3680 configured according to the [RFC4787] behavioral classification used 3681 in NATV2-MIB, but they include the two possibilities (full and 3682 restricted cone NAT) that satisfy requirements REQ-1 and REQ-8 of 3684 [RFC4787]. Note further that other behaviors defined in [RFC4787] 3685 are not considered in [RFC4008]. 3687 Having established a context for discussion, we are now in a position 3688 to compare the outputs provided to management from the [RFC4008] and 3689 NATV2-MIB modules. This comparison relates to the ability to compare 3690 results if testing with both MIBs implemented on the same device 3691 during a transition period. 3693 [RFC4008] provides three counters: incoming translations, outgoing 3694 translations, and discarded packets, at the granularities of 3695 interface, address map, and protocol, and incoming and outgoing 3696 translations at the levels of individual address bind, address port 3697 bind, and session entries. Implementation at the protocol and 3698 address map levels is optional. NATV2-MIB provides a single total 3699 (both directions) translations counter at the instance, protocol 3700 within instance, and subscriber levels. Given the differences in 3701 granularity, it appears that the only comparable measurement of 3702 translations between the two MIB modules would be through aggregation 3703 of the [RFC4008] interface counters to give a total number of 3704 translations for the NAT instance. 3706 NATV2-MIB has broken out the single discard counter into a number of 3707 different counters reflecting the cause of the discard in more 3708 detail, to help in trouble-shooting. Again, with the differing 3709 levels of granularity, the only comparable statistic would be through 3710 aggregation to a single value of total discards per NAT instance. 3712 Moving on to state variables, [RFC4008] offers counts of number of 3713 "address map" (i.e., address pool) entries used (excluding static 3714 entries) at the address map level, and number of entries in the 3715 address bind and address and port bind tables respectively. Finally, 3716 [RFC4008] provides a count of the number of sessions currently using 3717 each entry in the address and port bind table. None of these counts 3718 are directly comparable with the state values offered by NATV2-MIB, 3719 because of the exclusion of static entries at the address map level, 3720 and because of the differing models of the translation tables between 3721 [RFC4008] and the NATV2=MIB. 3723 6. Security Considerations 3725 A number of management objects defined in this MIB module have a MAX- 3726 ACCESS clause of read-write. Such objects may be considered 3727 sensitive or vulnerable in some network environments. The support 3728 for SET operations in a non-secure environment without proper 3729 protection can have a negative effect on network operations. These 3730 are the tables and objects and their sensitivity/vulnerability: 3732 Limits: An attacker setting a very low or very high limit can easily 3733 cause a denial-of-service situation. 3735 * natv2InstanceLimitAddressMapEntries; 3737 * natv2InstanceLimitPortMapEntries; 3739 * natv2InstanceLimitPendingFragments; 3741 * natv2InstanceLimitSubscriberActives; 3743 * natv2SubscriberLimitPortMapEntries. 3745 Notification thresholds: An attacker setting an arbitrarily low 3746 threshold can cause many useless notifications to be generated 3747 (subject to the notification interval). Setting an arbitrarily 3748 high threshold can effectively disable notifications, which could 3749 be used to hide another attack. 3751 * natv2InstanceThresholdAddressMapEntriesHigh; 3753 * natv2InstanceThresholdPortMapEntriesHigh; 3755 * natv2PoolThresholdUsageLow; 3757 * natv2PoolThresholdUsageHigh; 3759 * natv2SubscriberThresholdPortMapEntriesHigh. 3761 Notification intervals: An attacker setting a low notification 3762 interval in combination with a low threshold value can cause many 3763 useless notifications to be generated. 3765 * natv2InstanceNotificationInterval; 3767 * natv2PoolNotificationInterval; 3769 * natv2SubscriberNotificationInterval. 3771 Some of the readable objects in this MIB module (i.e., objects with a 3772 MAX-ACCESS other than not-accessible) may be considered sensitive or 3773 vulnerable in some network environments. It is thus important to 3774 control even GET and/or NOTIFY access to these objects and possibly 3775 to even encrypt the values of these objects when sending them over 3776 the network via SNMP. These are the tables and objects and their 3777 sensitivity/vulnerability: 3779 Objects that reveal host identities: Various objects can reveal the 3780 identity of private hosts that are engaged in a session with 3781 external end nodes. A curious outsider could monitor these to 3782 assess the number of private hosts being supported by the NAT 3783 device. Further, a disgruntled former employee of an enterprise 3784 could use the information to break into specific private hosts by 3785 intercepting the existing sessions or originating new sessions 3786 into the host. 3788 * entries in the natv2AddressMapTable; 3790 * entries in the natv2PortMapTable. 3792 Other objects that reveal NAT state: Other managed objects in this 3793 MIB may contain information that may be sensitive from a business 3794 perspective, in that they may represent NAT capabilities, business 3795 policies, and state information. 3797 * natv2SubscriberLimitPortMapEntries; 3799 * natv2InstancePortMappingBehavior; 3801 * natv2InstanceFilteringBehavior; 3803 * natv2InstancePoolingBehavior; 3805 * natv2InstanceFragmentBehavior; 3807 * natv2InstanceAddressMapEntries; 3809 * natv2InstancePortMapEntries. 3811 There are no objects that are sensitive in their own right, such as 3812 passwords or monetary amounts. 3814 SNMP versions prior to SNMPv3 did not include adequate security. 3815 Even if the network itself is secure (for example by using IPsec), 3816 there is no control as to who on the secure network is allowed to 3817 access and GET/SET (read/change/create/delete) the objects in this 3818 MIB module. 3820 Implementations SHOULD provide the security features described by the 3821 SNMPv3 framework (see [RFC3410]), and implementations claiming 3822 compliance to the SNMPv3 standard MUST include full support for 3823 authentication and privacy via the User-based Security Model (USM) 3824 [RFC3414] with the AES cipher algorithm [RFC3826]. Implementations 3825 MAY also provide support for the Transport Security Model (TSM) 3827 [RFC5591] in combination with a secure transport such as SSH 3828 [RFC5592] or TLS/DTLS [RFC6353]. 3830 Further, deployment of SNMP versions prior to SNMPv3 is NOT 3831 RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to 3832 enable cryptographic security. It is then a customer/operator 3833 responsibility to ensure that the SNMP entity giving access to an 3834 instance of this MIB module is properly configured to give access to 3835 the objects only to those principals (users) that have legitimate 3836 rights to indeed GET or SET (change/create/delete) them. 3838 7. IANA Considerations 3840 IANA is requested to assign an object identifier to the natv2MIB 3841 module, with prefix iso.org.dod.internet.mgmt.mib-2 in the Network 3842 Management Parameters registry [SMI-NUMBERS]. 3844 8. References 3846 8.1. Normative References 3848 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 3849 Requirement Levels", BCP 14, RFC 2119, March 1997. 3851 [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. 3852 Schoenwaelder, Ed., "Structure of Management Information 3853 Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. 3855 [RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J. 3856 Schoenwaelder, Ed., "Textual Conventions for SMIv2", STD 3857 58, RFC 2579, April 1999. 3859 [RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder, 3860 "Conformance Statements for SMIv2", STD 58, RFC 2580, 3861 April 1999. 3863 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 3864 Architecture for Describing Simple Network Management 3865 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 3866 December 2002. 3868 [RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model 3869 (USM) for version 3 of the Simple Network Management 3870 Protocol (SNMPv3)", STD 62, RFC 3414, December 2002. 3872 [RFC3489] Rosenberg, J., Weinberger, J., Huitema, C., and R. Mahy, 3873 "STUN - Simple Traversal of User Datagram Protocol (UDP) 3874 Through Network Address Translators (NATs)", RFC 3489, 3875 March 2003. 3877 [RFC3826] Blumenthal, U., Maino, F., and K. McCloghrie, "The 3878 Advanced Encryption Standard (AES) Cipher Algorithm in the 3879 SNMP User-based Security Model", RFC 3826, June 2004. 3881 [RFC4001] Daniele, M., Haberman, B., Routhier, S., and J. 3882 Schoenwaelder, "Textual Conventions for Internet Network 3883 Addresses", RFC 4001, February 2005. 3885 [RFC4787] Audet, F. and C. Jennings, "Network Address Translation 3886 (NAT) Behavioral Requirements for Unicast UDP", BCP 127, 3887 RFC 4787, January 2007. 3889 [RFC5591] Harrington, D. and W. Hardaker, "Transport Security Model 3890 for the Simple Network Management Protocol (SNMP)", STD 3891 78, RFC 5591, June 2009. 3893 [RFC5592] Harrington, D., Salowey, J., and W. Hardaker, "Secure 3894 Shell Transport Model for the Simple Network Management 3895 Protocol (SNMP)", RFC 5592, June 2009. 3897 [RFC6353] Hardaker, W., "Transport Layer Security (TLS) Transport 3898 Model for the Simple Network Management Protocol (SNMP)", 3899 STD 78, RFC 6353, July 2011. 3901 8.2. Informative References 3903 [I-D.perrault-behave-deprecate-nat-mib-v1] 3904 Perrault, S., Tsou, T., Sivakumar, S., and T. Taylor, 3905 "Deprecation of MIB Module NAT-MIB (Managed Objects for 3906 Network Address Translators (NAT)) (Work in Progress)", 3907 October 2014. 3909 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 3910 (IPv6) Specification", RFC 2460, December 1998. 3912 [RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address 3913 Translator (NAT) Terminology and Considerations", RFC 3914 2663, August 1999. 3916 [RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, 3917 "Introduction and Applicability Statements for Internet- 3918 Standard Management Framework", RFC 3410, December 2002. 3920 [RFC4008] Rohit, R., Srisuresh, P., Raghunarayan, R., Pai, N., and 3921 C. Wang, "Definitions of Managed Objects for Network 3922 Address Translators (NAT)", RFC 4008, March 2005. 3924 [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 3925 Stack Lite Broadband Deployments Following IPv4 3926 Exhaustion", RFC 6333, August 2011. 3928 [SMI-NUMBERS] 3929 "Network Management Parameters registry at IANA", 3930 . 3932 Authors' Addresses 3934 Simon Perreault 3935 Jive Communications 3936 Quebec, QC 3937 Canada 3939 Email: sperreault@jive.com 3941 Tina Tsou 3942 Huawei Technologies 3943 Bantian, Longgang District 3944 Shenzhen 518129 3945 PR China 3947 Email: tina.tsou.zouting@huawei.com 3949 Senthil Sivakumar 3950 Cisco Systems 3951 7100-8 Kit Creek Road 3952 Research Triangle Park, North Carolina 27709 3953 USA 3955 Phone: +1 919 392 5158 3956 Email: ssenthil@cisco.com 3958 Tom Taylor 3959 PT Taylor Consulting 3960 Ottawa 3961 Canada 3963 Email: tom.taylor.stds@gmail.com