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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Global Routing Operations T. Evens 3 Internet-Draft S. Bayraktar 4 Updates: 7854 (if approved) M. Bhardwaj 5 Intended status: Standards Track Cisco Systems 6 Expires: 9 September 2021 P. Lucente 7 NTT Communications 8 8 March 2021 10 Support for Local RIB in BGP Monitoring Protocol (BMP) 11 draft-ietf-grow-bmp-local-rib-10 13 Abstract 15 The BGP Monitoring Protocol (BMP) defines access to various Routing 16 Information Bases (RIBs). This document updates BMP (RFC 7854) by 17 adding access to the Local Routing Information Base (Loc-RIB), as 18 defined in RFC 4271. The Loc-RIB contains the routes that have been 19 selected by the local BGP speaker's Decision Process. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at https://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on 9 September 2021. 38 Copyright Notice 40 Copyright (c) 2021 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 45 license-info) in effect on the date of publication of this document. 46 Please review these documents carefully, as they describe your rights 47 and restrictions with respect to this document. Code Components 48 extracted from this document must include Simplified BSD License text 49 as described in Section 4.e of the Trust Legal Provisions and are 50 provided without warranty as described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 55 1.1. Alternative Method to Monitor Loc-RIB . . . . . . . . . . 5 56 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7 57 3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 7 58 4. Per-Peer Header . . . . . . . . . . . . . . . . . . . . . . . 8 59 4.1. Peer Type . . . . . . . . . . . . . . . . . . . . . . . . 8 60 4.2. Peer Flags . . . . . . . . . . . . . . . . . . . . . . . 8 61 5. Loc-RIB Monitoring . . . . . . . . . . . . . . . . . . . . . 9 62 5.1. Per-Peer Header . . . . . . . . . . . . . . . . . . . . . 9 63 5.2. Peer UP Notification . . . . . . . . . . . . . . . . . . 10 64 5.2.1. Peer UP Information . . . . . . . . . . . . . . . . . 10 65 5.3. Peer Down Notification . . . . . . . . . . . . . . . . . 11 66 5.4. Route Monitoring . . . . . . . . . . . . . . . . . . . . 11 67 5.4.1. ASN Encoding . . . . . . . . . . . . . . . . . . . . 11 68 5.4.2. Granularity . . . . . . . . . . . . . . . . . . . . . 11 69 5.5. Route Mirroring . . . . . . . . . . . . . . . . . . . . . 12 70 5.6. Statistics Report . . . . . . . . . . . . . . . . . . . . 12 71 6. Other Considerations . . . . . . . . . . . . . . . . . . . . 12 72 6.1. Loc-RIB Implementation . . . . . . . . . . . . . . . . . 12 73 6.1.1. Multiple Loc-RIB Peers . . . . . . . . . . . . . . . 12 74 6.1.2. Filtering Loc-RIB to BMP Receivers . . . . . . . . . 13 75 6.1.3. Changes to existing BMP sessions . . . . . . . . . . 13 76 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 77 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 78 8.1. BMP Peer Type . . . . . . . . . . . . . . . . . . . . . . 13 79 8.2. BMP Peer Flags . . . . . . . . . . . . . . . . . . . . . 13 80 8.3. Peer UP Information TLV . . . . . . . . . . . . . . . . . 14 81 8.4. Peer Down Reason code . . . . . . . . . . . . . . . . . . 14 82 9. Normative References . . . . . . . . . . . . . . . . . . . . 14 83 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 14 84 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 86 1. Introduction 88 This document defines a mechanism to monitor the BGP Loc-RIB state of 89 remote BGP instances without the need to establish BGP peering 90 sessions. BMP [RFC7854] does not define a method to send the BGP 91 instance Loc-RIB. It does define in section 8.2 of [RFC7854] locally 92 originated routes, but these routes are defined as the routes 93 originated into BGP. For example, locally sourced routes that are 94 redistributed. 96 Figure 1 shows the flow of received routes from one or more BGP peers 97 into the Loc-RIB. 99 +------------------+ +------------------+ 100 | Peer-A | | Peer-B | 101 /-- | | ---- | | --\ 102 | | Adj-RIB-In (Pre) | | Adj-RIB-In (Pre) | | 103 | +------------------+ +------------------+ | 104 | | | | 105 | Filters/Policy -| Filters/Policy -| | 106 | V V | 107 | +------------------ +------------------+ | 108 | | Adj-RIB-In (Post)| | Adj-RIB-In (Post)| | 109 | +------------------ +------------------+ | 110 | | | | 111 | Selected -| Selected -| | 112 | V V | 113 | +-----------------------------------------+ | 114 | | Loc-RIB | | 115 | +-----------------------------------------+ | 116 | | 117 | ROUTER/BGP Instance | 118 \----------------------------------------------------/ 120 Figure 1: BGP peering Adj-RIBs-In into Loc-RIB 122 Figure 2 (Locally Originated into Loc-RIB) illustrates how 123 redistributed or otherwise originated routes get installed into the 124 Loc-RIB based on the decision process selection in RFC 4271 125 [RFC4271]. 127 /--------------------------------------------------------\ 128 | | 129 | +----------+ +----------+ +----------+ +----------+ | 130 | | IS-IS | | OSPF | | Static | | BGP | | 131 | +----------+ +----------+ +----------+ +----------+ | 132 | | | | | | 133 | | | | 134 | | Redistributed or originated into BGP | | 135 | | | | 136 | | | | | | 137 | V V V V | 138 | +----------------------------------------------+ | 139 | | Loc-RIB | | 140 | +----------------------------------------------+ | 141 | | 142 | ROUTER/BGP Instance | 143 \--------------------------------------------------------/ 145 Figure 2: Locally Originated into Loc-RIB 147 The following are some use-cases for Loc-RIB access: 149 * The Adj-RIB-In for a given peer Post-Policy may contain hundreds 150 of thousands of routes, with only a handful of routes selected and 151 installed in the Loc-RIB after best-path selection. Some 152 monitoring applications, such as ones that need only to correlate 153 flow records to Loc-RIB entries, only need to collect and monitor 154 the routes that are actually selected and used. 156 Requiring the applications to collect all Adj-RIB-In Post-Policy 157 data forces the applications to receive a potentially large 158 unwanted data set and to perform the BGP decision process 159 selection, which includes having access to the IGP next-hop 160 metrics. While it is possible to obtain the IGP topology 161 information using BGP-LS, it requires the application to implement 162 SPF and possibly CSPF based on additional policies. This is 163 overly complex for such a simple application that only needs to 164 have access to the Loc-RIB. 166 * It is common to see frequent changes over many BGP peers, but 167 those changes do not always result in the router's Loc-RIB 168 changing. The change in the Loc-RIB can have a direct impact on 169 the forwarding state. It can greatly reduce time to troubleshoot 170 and resolve issues if operators have the history of Loc-RIB 171 changes. For example, a performance issue might have been seen 172 for only a duration of 5 minutes. Post troubleshooting this issue 173 without Loc-RIB history hides any decision based routing changes 174 that might have happened during those five minutes. 176 * Operators may wish to validate the impact of policies applied to 177 Adj-RIB-In by analyzing the final decision made by the router when 178 installing into the Loc-RIB. For example, in order to validate if 179 multi-path prefixes are installed as expected for all advertising 180 peers, the Adj-RIB-In Post-Policy and Loc-RIB needs to be 181 compared. This is only possible if the Loc-RIB is available. 182 Monitoring the Adj-RIB-In for this router from another router to 183 derive the Loc-RIB is likely to not show same installed prefixes. 184 For example, the received Adj-RIB-In will be different if add- 185 paths is not enabled or if maximum number of equal paths are 186 different from Loc-RIB to routes advertised. 188 This document adds Loc-RIB to the BGP Monitoring Protocol and 189 replaces Section 8.2 of [RFC7854] Locally Originated Routes. 191 1.1. Alternative Method to Monitor Loc-RIB 193 Loc-RIB is used to build Adj-RIB-Out when advertising routes to a 194 peer. It is therefore possible to derive the Loc-RIB of a router by 195 monitoring the Adj-RIB-In Pre-Policy from another router. At scale 196 this becomes overly complex and error prone. 198 /------------------------------------------------------\ 199 | ROUTER1 BGP Instance | 200 | | 201 | +--------------------------------------------+ | 202 | | Loc-RIB | | 203 | +--------------------------------------------+ | 204 | | | | 205 | +------------------+ +------------------+ | 206 | | Peer-ROUTER2 | | Peer-ROUTER3 | | 207 | | Adj-RIB-Out (Pre)| | Adj-RIB-Out (Pre)| | 208 | +------------------+ +------------------+ | 209 | Filters/Policy -| Filters/Policy -| | 210 | V V | 211 | +-------------------+ +-------------------+ | 212 | | Adj-RIB-Out (Post)| | Adj-RIB-Out (Post)| | 213 | +-------------------+ +-------------------+ | 214 | | | | 215 \------------- | ------------------------ | -----------/ 216 BGP | BGP | 217 Peer | Peer | 218 +------------------+ +------------------+ 219 | Peer-ROUTER1 | | Peer-ROUTER1 | 220 /--| |--\ /--| | --\ 221 | | Adj-RIB-In (Pre) | | | | Adj-RIB-In (Pre) | | 222 | +------------------+ | | +------------------+ | 223 | | | | 224 | ROUTER2/BGP Instance | | ROUTER3/BGP Instance | 225 \------------------------/ \-------------------------/ 226 | | 227 v v 228 ROUTER2 BMP Feed ROUTER3 BMP Feed 230 Figure 3: Alternative method to monitor Loc-RIB 232 The setup needed to monitor the Loc-RIB of a router requires another 233 router with a peering session to the target router that is to be 234 monitored. As shown in Figure 3, the target router Loc-RIB is 235 advertised via Adj-RIB-Out to the BMP router over a standard BGP 236 peering session. The BMP router then forwards Adj-RIB-In Pre-Policy 237 to the BMP receiver. 239 BMP lacking access to Loc-RIB introduces the need for additional 240 resources: 242 * Requires at least two routers when only one router was to be 243 monitored. 245 * Requires additional BGP peering to collect the received updates 246 when peering may have not even been required in the first place. 247 For example, VRFs with no peers, redistributed BGP-LS with no 248 peers, segment routing egress peer engineering where no peers have 249 link-state address family enabled. 251 Complexities introduced by the lack of access to Loc-RIB in order to 252 derive (e.g. correlate) peer to router Loc-RIB: 254 * Adj-RIB-Out received as Adj-RIB-In from another router may have a 255 policy applied that filters, generates aggregates, suppresses more 256 specifics, manipulates attributes, or filters routes. Not only 257 does this invalidate the Loc-RIB view, it adds complexity when 258 multiple BMP routers may have peering sessions to the same router. 259 The BMP receiver user is left with the error prone task of 260 identifying which peering session is the best representative of 261 the Loc-RIB. 263 * BGP peering is designed to work between administrative domains and 264 therefore does not need to include internal system level 265 information of each peering router (e.g. the system name or 266 version information). In order to derive a Loc-RIB to a router, 267 the router name or other system information is needed. The BMP 268 receiver and user are forced to do some type of correlation using 269 what information is available in the peering session (e.g. peering 270 addresses, ASNs, and BGP-IDs). This leads to error prone 271 correlations. 273 * The BGP-IDs and session addresses to router correlation requires 274 additional data, such as router inventory. This additional data 275 provides the BMP receiver the ability to map and correlate the 276 BGP-IDs and/or session addresses, but requires the BMP receiver to 277 somehow obtain this data outside of BMP. How this data is 278 obtained and the accuracy of the data directly effects the 279 integrity of the correlation. 281 2. Terminology 283 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 284 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 285 "OPTIONAL" in this document are to be interpreted as described in BCP 286 14 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when, they 287 appear in all capitals, as shown here. 289 3. Definitions 290 * BGP Instance: refers to an instance of an instance of BGP-4 291 [RFC4271] and considerations in section 8.1 of [RFC7854] do apply 292 to it. 294 * Adj-RIB-In: As defined in [RFC4271], "The Adj-RIBs-In contains 295 unprocessed routing information that has been advertised to the 296 local BGP speaker by its peers." This is also referred to as the 297 pre-policy Adj-RIB-In in this document. 299 * Adj-RIB-Out: As defined in [RFC4271], "The Adj-RIBs-Out contains 300 the routes for advertisement to specific peers by means of the 301 local speaker's UPDATE messages." 303 * Loc-RIB: As defined in section 9.4 of [RFC4271], "The Loc-RIB 304 contains the routes that have been selected by the local BGP 305 speaker's Decision Process." Note that the Loc-RIB state as 306 monitored through BMP might also contain routes imported from 307 other routing protocols such as an IGP, or local static routes. 309 * Pre-Policy Adj-RIB-Out: The result before applying the outbound 310 policy to an Adj-RIB-Out. This normally represents a similar view 311 of the Loc-RIB but may contain additional routes based on BGP 312 peering configuration. 314 * Post-Policy Adj-RIB-Out: The result of applying outbound policy to 315 an Adj-RIB-Out. This MUST be what is actually sent to the peer. 317 4. Per-Peer Header 319 4.1. Peer Type 321 A new peer type is defined for Loc-RIB to distinguish that it 322 represents Loc-RIB with or without RD and local instances. 323 Section 4.2 of [RFC7854] defines a Local Instance Peer type, which is 324 for the case of non-RD peers that have an instance identifier. 326 This document defines the following new peer type: 328 * Peer Type = 3: Loc-RIB Instance Peer 330 4.2. Peer Flags 332 In section 4.2 of [RFC7854], the "locally sourced routes" comment 333 under the L flag description is removed. If locally sourced routes 334 are communicated using BMP, they MUST be conveyed using the Loc-RIB 335 instance peer type. 337 The per-peer header flags for Loc-RIB Instance Peer type are defined 338 as follows: 340 0 1 2 3 4 5 6 7 341 +-+-+-+-+-+-+-+-+ 342 |F| Reserved | 343 +-+-+-+-+-+-+-+-+ 345 * The F flag indicates that the Loc-RIB is filtered. This MUST be 346 set when only a subset of Loc-RIB routes is sent to the BMP 347 collector. 349 The remaining bits are reserved for future use. They MUST be 350 transmitted as 0 and their values MUST be ignored on receipt. 352 5. Loc-RIB Monitoring 354 The Loc-RIB contains all routes selected by the BGP protocol Decision 355 Process as described in section 9.1 of [RFC4271]. These routes 356 include those learned from BGP peers via its Adj-RIBs-In post-policy, 357 as well as routes learned by other means as per section 9.4 of 358 [RFC4271]. Examples of these include redistribution of routes from 359 other protocols into BGP or otherwise locally originated (ie. 360 aggregate routes). 362 As mentioned in Section 4.2 a subset of Loc-RIB routes MAY be sent to 363 a BMP collector by setting the F flag. 365 5.1. Per-Peer Header 367 All peer messages that include a per-peer header section 4.2 of 368 [RFC7854] MUST use the following values: 370 * Peer Type: Set to 3 to indicate Loc-RIB Instance Peer. 372 * Peer Distinguisher: Zero filled if the Loc-RIB represents the 373 global instance. Otherwise set to the route distinguisher or 374 unique locally defined value of the particular instance the Loc- 375 RIB belongs to. 377 * Peer Address: Zero-filled. Remote peer address is not applicable. 378 The V flag is not applicable with Loc-RIB Instance peer type 379 considering addresses are zero-filed. 381 * Peer AS: Set to the primary router BGP ASN. 383 * Peer BGP ID: Set to the BGP instance global or RD (e.g. VRF) 384 specific router-id section 1.1 of [RFC7854]. 386 * Timestamp: The time when the encapsulated routes were installed in 387 The Loc-RIB, expressed in seconds and microseconds since midnight 388 (zero hour), January 1, 1970 (UTC). If zero, the time is 389 unavailable. Precision of the timestamp is implementation- 390 dependent. 392 5.2. Peer UP Notification 394 Peer UP notifications follow section 4.10 of [RFC7854] with the 395 following clarifications: 397 * Local Address: Zero-filled, local address is not applicable. 399 * Local Port: Set to 0, local port is not applicable. 401 * Remote Port: Set to 0, remote port is not applicable. 403 * Sent OPEN Message: This is a fabricated BGP OPEN message. 404 Capabilities MUST include the 4-octet ASN and all necessary 405 capabilities to represent the Loc-RIB route monitoring messages. 406 Only include capabilities if they will be used for Loc-RIB 407 monitoring messages. For example, if add-paths is enabled for 408 IPv6 and Loc-RIB contains additional paths, the add-paths 409 capability should be included for IPv6. In the case of add-paths, 410 the capability intent of advertise, receive or both can be ignored 411 since the presence of the capability indicates enough that add- 412 paths will be used for IPv6. 414 * Received OPEN Message: Repeat of the same Sent Open Message. The 415 duplication allows the BMP receiver to use existing parsing. 417 5.2.1. Peer UP Information 419 The following Peer UP information TLV type is added: 421 * Type = 3: VRF/Table Name. The Information field contains a UTF-8 422 string whose value MUST be equal to the value of the VRF or table 423 name (e.g. RD instance name) being conveyed. The string size 424 MUST be within the range of 1 to 255 bytes. 426 The VRF/Table Name TLV is optionally included. For consistency, 427 it is RECOMMENDED that the VRF/Table Name always be included. The 428 default value of "global" MUST be used for the default Loc-RIB 429 instance with a zero-filled distinguisher. If the TLV is 430 included, then it MUST also be included in the Peer Down 431 notification. 433 Multiple TLVs of the same type can be repeated as part of the same 434 message, for example to convey a filtered view of a VRF. A BMP 435 receiver should append multiple TLVs of the same type to a set in 436 order to support alternate or additional names for the same peer. If 437 multiple strings are included, their ordering MUST be preserved when 438 they are reported. 440 5.3. Peer Down Notification 442 Peer down notification MUST use reason code 6. Following the reason 443 is data in TLV format. The following peer Down information TLV type 444 is defined: 446 * Type = 3: VRF/Table Name. The Information field contains a UTF-8 447 string whose value MUST be equal to the value of the VRF or table 448 name (e.g. RD instance name) being conveyed. The string size 449 MUST be within the range of 1 to 255 bytes. The VRF/Table Name 450 informational TLV MUST be included if it was in the Peer UP. 452 5.4. Route Monitoring 454 Route Monitoring messages are used for initial synchronization of the 455 Loc-RIB. They are also used to convey incremental Loc-RIB changes. 457 As defined in section 4.3 of [RFC7854], "Following the common BMP 458 header and per-peer header is a BGP Update PDU." 460 5.4.1. ASN Encoding 462 Loc-RIB route monitor messages MUST use 4-byte ASN encoding as 463 indicated in PEER UP sent OPEN message (Section 5.2) capability. 465 5.4.2. Granularity 467 State compression and throttling SHOULD be used by a BMP sender to 468 reduce the amount of route monitoring messages that are transmitted 469 to BMP receivers. With state compression, only the final resultant 470 updates are sent. 472 For example, prefix 192.0.2.0/24 is updated in the Loc-RIB 5 times 473 within 1 second. State compression of BMP route monitor messages 474 results in only the final change being transmitted. The other 4 475 changes are suppressed because they fall within the compression 476 interval. If no compression was being used, all 5 updates would have 477 been transmitted. 479 A BMP receiver should expect that Loc-RIB route monitoring 480 granularity can be different by BMP sender implementation. 482 5.5. Route Mirroring 484 Route mirroring is not applicable to Loc-RIB and Route Mirroring 485 messages SHOULD be ignored. 487 5.6. Statistics Report 489 Not all Stat Types are relevant to Loc-RIB. The Stat Types that are 490 relevant are listed below: 492 * Stat Type = 8: (64-bit Gauge) Number of routes in Loc-RIB. 494 * Stat Type = 10: Number of routes in per-AFI/SAFI Loc-RIB. The 495 value is structured as: 2-byte AFI, 1-byte SAFI, followed by a 64- 496 bit Gauge. 498 6. Other Considerations 500 6.1. Loc-RIB Implementation 502 There are several methods for a BGP speaker to implement Loc-RIB 503 efficiently. In all methods, the implementation emulates a peer with 504 Peer UP and DOWN messages to convey capabilities as well as Route 505 Monitor messages to convey Loc-RIB. In this sense, the peer that 506 conveys the Loc-RIB is a local router emulated peer. 508 6.1.1. Multiple Loc-RIB Peers 510 There MUST be multiple emulated peers for each Loc-RIB instance, such 511 as with VRFs. The BMP receiver identifies the Loc-RIB by the peer 512 header distinguisher and BGP ID. The BMP receiver uses the VRF/ 513 Table Name from the PEER UP information to associate a name to the 514 Loc-RIB. 516 In some implementations, it might be required to have more than one 517 emulated peer for Loc-RIB to convey different address families for 518 the same Loc-RIB. In this case, the peer distinguisher and BGP ID 519 should be the same since it represents the same Loc-RIB instance. 520 Each emulated peer instance MUST send a PEER UP with the OPEN message 521 indicating the address family capabilities. A BMP receiver MUST 522 process these capabilities to know which peer belongs to which 523 address family. 525 6.1.2. Filtering Loc-RIB to BMP Receivers 527 There maybe be use-cases where BMP receivers should only receive 528 specific routes from Loc-RIB. For example, IPv4 unicast routes may 529 include IBGP, EBGP, and IGP but only routes from EBGP should be sent 530 to the BMP receiver. Alternatively, it may be that only IBGP and 531 EBGP that should be sent and IGP redistributed routes should be 532 excluded. In these cases where the Loc-RIB is filtered, the F flag 533 is set to 1 to indicate to the BMP receiver that the Loc-RIB is 534 filtered. If multiple filters are associated to the same Loc-RIB, a 535 Table Name MUST be used in order to allow a BMP receiver to make the 536 right associations. 538 6.1.3. Changes to existing BMP sessions 540 In case of any change that results in the alteration of behaviour of 541 an existing BMP session, ie. changes to filtering and table names, 542 the session MUST be bounced with a Peer DOWN/Peer UP sequence. 544 7. Security Considerations 546 The same considerations as in section 11 of [RFC7854] apply to this 547 document. Implementations of this protocol SHOULD require to 548 establish sessions with authorized and trusted monitoring devices. 549 It is also believed that this document does not add any additional 550 security considerations. 552 8. IANA Considerations 554 This document requests that IANA assign the following new parameters 555 to the BMP parameters name space (https://www.iana.org/assignments/ 556 bmp-parameters/bmp-parameters.xhtml). 558 8.1. BMP Peer Type 560 This document defines a new peer type (Section 4.1): 562 * Peer Type = 3: Loc-RIB Instance Peer 564 8.2. BMP Peer Flags 566 This document defines a new flag (Section 4.2) and proposes that peer 567 flags are specific to the peer type: 569 * The F flag indicates that the Loc-RIB is filtered. This indicates 570 that the Loc-RIB does not represent the complete routing table. 572 8.3. Peer UP Information TLV 574 This document defines the following new BMP PEER UP informational 575 message TLV types (Section 5.2.1): 577 * Type = 3: VRF/Table Name. The Information field contains a UTF-8 578 string whose value MUST be equal to the value of the VRF or table 579 name (e.g. RD instance name) being conveyed. The string size 580 MUST be within the range of 1 to 255 bytes. 582 8.4. Peer Down Reason code 584 This document defines the following new BMP Peer Down reason code 585 (Section 5.3): 587 * Type = 6: Local system closed, TLV data follows. 589 9. Normative References 591 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 592 Requirement Levels", BCP 14, RFC 2119, 593 DOI 10.17487/RFC2119, March 1997, 594 . 596 [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A 597 Border Gateway Protocol 4 (BGP-4)", RFC 4271, 598 DOI 10.17487/RFC4271, January 2006, 599 . 601 [RFC7854] Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP 602 Monitoring Protocol (BMP)", RFC 7854, 603 DOI 10.17487/RFC7854, June 2016, 604 . 606 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 607 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 608 May 2017, . 610 Acknowledgements 612 The authors would like to thank John Scudder, Jeff Haas and Mukul 613 Srivastava for their valuable input. 615 Authors' Addresses 617 Tim Evens 618 Cisco Systems 619 2901 Third Avenue, Suite 600 620 Seattle, WA 98121 621 United States of America 623 Email: tievens@cisco.com 625 Serpil Bayraktar 626 Cisco Systems 627 3700 Cisco Way 628 San Jose, CA 95134 629 United States of America 631 Email: serpil@cisco.com 633 Manish Bhardwaj 634 Cisco Systems 635 3700 Cisco Way 636 San Jose, CA 95134 637 United States of America 639 Email: manbhard@cisco.com 641 Paolo Lucente 642 NTT Communications 643 Siriusdreef 70-72 644 2132 Hoofddorp 645 Netherlands 647 Email: paolo@ntt.net