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'I-D.ietf-rtgwg-bgp-routing-large-dc') ** Obsolete normative reference: RFC 5575 (Obsoleted by RFC 8955) ** Obsolete normative reference: RFC 7752 (Obsoleted by RFC 9552) == Outdated reference: A later version (-19) exists of draft-ietf-idr-bgpls-segment-routing-epe-17 Summary: 3 errors (**), 0 flaws (~~), 11 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Working Group N. Wu 3 Internet-Draft Z. Zhuang 4 Intended status: Standards Track H. Chen 5 Expires: April 25, 2019 Huawei 6 October 22, 2018 8 BGP Extensions for IDs Allocation 9 draft-wu-idr-bgp-segment-allocation-ext-01 11 Abstract 13 This document describes extensions to the BGP-LS for IDs allocation. 14 The IDs are SIDs for segment routing and indirection IDs for flow 15 redirect. They are distributed to their domains if needed. 17 Requirements Language 19 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 20 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 21 document are to be interpreted as described in RFC 2119 [RFC2119]. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on April 25, 2019. 40 Copyright Notice 42 Copyright (c) 2018 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 59 3. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 3 60 3.1. Node NLRI for IDs Allocation . . . . . . . . . . . . . . 3 61 3.2. Link NLRI for IDs Allocation . . . . . . . . . . . . . . 4 62 3.3. Prefix NLRI for IDs Allocation . . . . . . . . . . . . . 5 63 4. Application Examples . . . . . . . . . . . . . . . . . . . . 6 64 4.1. Allocating IDs for DC BGP Network . . . . . . . . . . . . 6 65 4.1.1. Node-SID Distribution via Prefix NLRI . . . . . . . . 7 66 4.1.2. Adj-SID Distribution via Link NLRI . . . . . . . . . 8 67 4.1.3. IID Distribution via Node NLRI . . . . . . . . . . . 9 68 4.2. Allocating IDs for IGP Network . . . . . . . . . . . . . 9 69 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 70 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 71 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 72 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 73 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 74 8.2. Informative References . . . . . . . . . . . . . . . . . 11 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 77 1. Introduction 79 In a network with a central controller, the controller has the link 80 state information of the network, including traffic engineering 81 information. In addition, the controller allocates and manages the 82 resources of the network in general. It is natural and beneficial 83 for the controller to allocate and manage IDs as a kind of network 84 resources. 86 This document proposes extensions to the BGP-LS as a controller for 87 allocating Segment Identifers (SIDs) for segment routing (SR) and 88 indirection identifiers (IIDs) for flow redirect. If needed, some 89 IDs will be distributed into their network domains. 91 2. Terminology 93 The following terminology is used in this document. 95 SR: Segment Routing. 97 SID: Segment Identifier. 99 IID: Indirection Identifier. 101 SR-Path: Segment Routing Path. 103 SR-Tunnel: Segment Routing Tunnel. 105 RR: Route Reflector. 107 MPP: MPLS Path Programming. 109 NAI: Node or Adjacency Identifier. 111 GTID: Global Tunnel Identifier. It is used to identify a tunnel in 112 a network. 114 TED: Traffic Engineering Database. 116 3. Protocol Extensions 118 This section defines a new Protocol-ID, called IDs-Allocation (IDA), 119 in the Procotol-ID field of Link State NLRI. The use of the new 120 Protocol-ID allows separation and differentiation between the NLRIs 121 carrying IDs Allocation information from the NLRIs carrying IGP link- 122 state information defined in [RFC7752]. 124 3.1. Node NLRI for IDs Allocation 126 The Node NLRI with the new Protocol-ID is used for allocating the IDs 127 associated with a node. It has the same format (refer to the 128 Figure below) as that defined in [RFC7752] and may contain the 129 descriptor and attributes defined in [RFC7752]. 131 0 1 2 3 132 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 133 +-+-+-+-+-+-+-+-+ 134 |IDs-Allocation | Protocol-ID 135 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 136 | Identifier | 137 | (64 bits) | 138 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 139 ~ Local Node Descriptor ~ 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 ~ Node IDs Allocation ~ 142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 144 Where: 146 Protocol-ID: set to IDs-Allocation, a new Protocol-ID. 148 Local Node Descriptor: defined in [RFC7752], can be reused. 150 Node IDs Allocation: TLVs or sub-TLVs for IDs associated with the 151 node given by the Local Node Descriptor. 153 Node IDs Allocation field may contain some of the followings: 155 SR-Capabilities TLV (1034): It contains the Segment Routing Global 156 Base (SRGB) range(s) allocated for the node. 158 SR Local Block TLV (1036): The SR Local Block (SRLB) TLV contains 159 the range(s) of SIDs/labels allocated to the node for local SIDs. 161 IID Flow Redirect TLV (TBD): A new TLV that contains an 162 Indireection ID (IID) and a Flow Specification for redirecting 163 traffic flow given by the Flow Specification to the tunnel 164 indicated by the IID. Its format is shown below. 166 0 1 2 3 167 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 169 | Type: Flow Redirect (TBD) | Length | 170 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 171 | Reserved | Flags(1 octet)| ID-Type | 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 173 | Indirection ID | 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 ~ Flow Specification ~ 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 IID Flow Redirect TLV 180 Where Flags, ID-Type and Indirection ID are the same as those defined 181 in [I-D.ietf-idr-flowspec-path-redirect]. The contents of Flow 182 Specification is the same as that defined in [RFC5575]. 184 3.2. Link NLRI for IDs Allocation 186 The Link NLRI with the new Protocol-ID is used for allocating the IDs 187 associated with a link. It has the same format (refer to the 188 Figure below) as that defined in in [RFC7752] and may contain the 189 descriptors and attributes defined in [RFC7752]. 191 0 1 2 3 192 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 193 +-+-+-+-+-+-+-+-+ 194 |IDs-Allocation | Protocol-ID 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 196 | Identifier | 197 | (64 bits) | 198 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 ~ Local Node Descriptor ~ 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 201 ~ Remote Node Descriptor ~ 202 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 ~ Link Descriptor ~ 204 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 205 ~ Link IDs Allocation ~ 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 Where: 210 Protocol-ID: set to IDs-Allocation, a new Protocol-ID. 212 Node Descriptors: defined in [RFC7752], can be reused. 214 Link Descriptor: defined in [RFC7752], can be reused. 216 Link IDs Allocation: TLVs or sub-TLVs for IDs associated with the 217 link given by the Link Descriptor. 219 Link IDs Allocation field may contain some of the followings: 221 Adj-SID TLV (1099): It contains the Segment Identifier (SID) 222 allocated for the link/adjacency. 224 LAN Adj-SID TLV (1100): It contains the Segment Identifier (SID) 225 allocated for the adjacency/link to a non-DR router on a 226 broadcast, NBMA, or hybrid link. 228 3.3. Prefix NLRI for IDs Allocation 230 The Prefix NLRI with the new Protocol-ID is used for allocating the 231 IDs associated with a prefix. It has the same format (refer to the 232 Figure below) as that defined in in [RFC7752] and may contain the 233 descriptors and attributes defined in [RFC7752]. 235 0 1 2 3 236 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 237 +-+-+-+-+-+-+-+-+ 238 |IDs-Allocation | Protocol-ID 239 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 240 | Identifier | 241 | (64 bits) | 242 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 243 ~ Local Node Descriptor ~ 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 245 ~ Prefix Descriptor ~ 246 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 ~ Prefix IDs Allocation ~ 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 250 Where: 252 Protocol-ID: set to IDs-Allocation, a new Protocol-ID. 254 Local Node Descriptor: defined in [RFC7752], can be reused. 256 Prefix Descriptor: defined in [RFC7752], can be reused. 258 Prefix IDs Allocation: TLVs or sub-TLVs for IDs associated with 259 the prefix given by the Prefix Descriptor. 261 Prefix IDs Allocation field may contain some of the followings: 263 Prefix-SID TLV (1158): It contains the Segment Identifier (SID) 264 allocated for the prefix. 266 Prefix Range TLV (1159): It contains a range of prefixes and the 267 Segment Identifier (SID)s allocated for the prefixes. 269 4. Application Examples 271 4.1. Allocating IDs for DC BGP Network 273 BGP may be the only routing protocol in some networks, such as the DC 274 network described in [I-D.ietf-rtgwg-bgp-routing-large-dc]. If SR is 275 used in this case, it is better for a controller to allocate SIDs and 276 distribute them in the network. 278 In the DC network shown below, it is assumed: 280 Node NX has a loopback 1.1.1.X/32. For example, N7 has loopback 281 1.1.1.7/32. 283 Each node peers with its neighbors and the Controller via BGP 284 session. 286 The BGP Router ID and AS of Node NX are 1.1.1.X and X respectively. 288 /----------\ 289 | | 290 | Controller | 291 | | 292 \----------/ 293 | 294 +-----------------------+-------------------------------+ 295 | | | 296 | +------+ | +------+ | 297 | | N7 |-+-| N8 | Tier-1 | 298 | +------+ +------+ | 299 | | | | | | 300 | +---------+ | | +----------+ | 301 | | +-------+--+-------+--+-------+ | | 302 | | | | | | | | | | 303 | +----+ +----+ +----+ +----+ | 304 | | N3 |-----| N4 | | N5 |-----| N6 | Tier-2 | 305 | +----+ +----+ +----+ +----+ | 306 | | | | | | 307 | | +-----+ | | +-----+ | | 308 | +-| N1 |-+ +-| N2 |-+ Tier-3 | 309 | +-----+ +-----+ | 310 | | | | | | | | 311 | <- Servers -> <- Servers -> | 312 +-------------------------------------------------------+ 314 After the controller gets the topology information of this BGP 315 network, it can start to allocate SIDs and distribute them in the 316 network. 318 4.1.1. Node-SID Distribution via Prefix NLRI 320 In order to distribute a Node-SID for a router (e.g., N7), Controller 321 allocates a SID for its loopback and advertises a Prefix NLRI 322 containing the SID for the loopback as a prefix to all the routers in 323 the BGP Network. The following is an example of Prefix NLRI for Node 324 N7's SID. 326 o Protocol-ID set to the new Protocol-ID: IDs-Allocation 328 o Local Node Descriptor contains 330 * BGP Router-ID: 1.1.1.7 331 * Local ASN: 7 333 o Prefix Descriptor 335 * 1.1.1.7/32 337 o Prefix Attribute contains 339 * Prefix-SID TLV (1158): SID for 1.1.1.7/32 with N-Flag=1 (Node- 340 Flag). 342 * Other Prefix Attributes. 344 4.1.2. Adj-SID Distribution via Link NLRI 346 In order to distribute a Adj-SID for a router, Controller allocates a 347 SID for the adjacency/link and advertise a Link NLRI containing the 348 SID for the adjacency to all the routers of the BGP Network. The 349 following is an example of Link NLRI for the SID of the adjacency/ 350 link from N7 to N8. 352 o Protocol-ID set to the new Protocol-ID: IDs-Allocation 354 o Local Node Descriptors contains 356 * BGP Router-ID: 1.1.1.7 358 * Local ASN: 7 360 o Remote Node Descriptor contains 362 * BGP Router-ID: 1.1.1.8 364 * Local ASN: 8 366 o Link Descriptor 368 * BGP session IPv4 local address: 1.1.1.7 370 * BGP session IPv4 peer address: 1.1.1.8 372 o Link Attribute contains 374 * Adj-SID TLV (1099): SID for Adjacency from N7 to N8 376 * Other Link Attributes. 378 4.1.3. IID Distribution via Node NLRI 380 In order to distribute an IID Flow Redirect, Controller allocates an 381 IID for a Flow Specification and advertises a Node NLRI containing 382 the IID and the Flow Specification to all the routers in the BGP 383 Network. The following is an example of Node NLRI for the IID Flow 384 Redirect, where Local Node Descriptor describes the Controller (its 385 BGP Router-ID is 7.7.7.7 and ASN is 7777). 387 o Protocol-ID set to the new Protocol-ID: IDs-Allocation 389 o Local Node Descriptor contains 391 * BGP Router-ID: 7.7.7.7 393 * Local ASN: 7777 395 o Node Attribute contains 397 * IID Flow Redirect TLV (TBD): IID and Flow Specification 399 * Other Node Attributes. 401 4.2. Allocating IDs for IGP Network 403 In an IGP network with SR capability, a controller may allocate SIDs 404 for SR and send the SIDs to their responding nodes in the network. 405 Each of the nodes distributes the SIDs it receives to the other nodes 406 in the network through IGP. 408 For example, for a node A, the controller may allocate a SID for a 409 loopback of the node A and send the SID to the node A through using a 410 Prefix NLRI. The node A distributes the SID to the other nodes in 411 the network via IGP. The Prefix NLRI contains: 413 o Protocol-ID set to the new Protocol-ID: IDs-Allocation 415 o Local Node Descriptor indicating the node A 417 o Prefix Descriptor describing the loopback as prefix 419 o Prefix Attribute containing 421 * Prefix-SID TLV (1158): SID for the loopback with N-Flag=1 422 (Node-Flag). 424 * Other Prefix Attributes. 426 5. IANA Considerations 428 This document requests assigning a code-point from the registry "BGP- 429 LS Protocol-IDs" as follows: 431 +-------------+-----------------------------------+-------------+ 432 | Protocol-ID | Description | Reference | 433 +-------------+-----------------------------------+-------------+ 434 | TBD | IDs Allocation | Section 3 | 435 +-------------+-----------------------------------+-------------+ 437 This document requests assigning a code-point from the registry "BGP- 438 LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute 439 TLVs" as follows: 441 +----------------+-----------------------------------+-------------+ 442 | TLV Code Point | Description | Reference | 443 +----------------+-----------------------------------+-------------+ 444 | TBD | IID Flow Redirect | Section 3.1 | 445 +----------------+-----------------------------------+-------------+ 447 6. Security Considerations 449 Protocol extensions defined in this document do not affect the BGP 450 security other than those as discussed in the Security Considerations 451 section of [RFC7752]. 453 7. Acknowledgements 455 The authors would like to thank Robin Li, and others for their 456 valuable suggestions and comments on this draft. 458 8. References 460 8.1. Normative References 462 [I-D.ietf-idr-flowspec-path-redirect] 463 Velde, G., Patel, K., and Z. Li, "Flowspec Indirection-id 464 Redirect", draft-ietf-idr-flowspec-path-redirect-06 (work 465 in progress), June 2018. 467 [I-D.ietf-isis-segment-routing-extensions] 468 Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., 469 Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, 470 "IS-IS Extensions for Segment Routing", draft-ietf-isis- 471 segment-routing-extensions-19 (work in progress), July 472 2018. 474 [I-D.ietf-rtgwg-bgp-routing-large-dc] 475 Lapukhov, P., Premji, A., and J. Mitchell, "Use of BGP for 476 routing in large-scale data centers", draft-ietf-rtgwg- 477 bgp-routing-large-dc-11 (work in progress), June 2016. 479 [I-D.ietf-spring-segment-routing] 480 Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., 481 Litkowski, S., and R. Shakir, "Segment Routing 482 Architecture", draft-ietf-spring-segment-routing-15 (work 483 in progress), January 2018. 485 [I-D.ietf-spring-segment-routing-ldp-interop] 486 Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., and 487 S. Litkowski, "Segment Routing interworking with LDP", 488 draft-ietf-spring-segment-routing-ldp-interop-15 (work in 489 progress), September 2018. 491 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 492 Requirement Levels", BCP 14, RFC 2119, 493 DOI 10.17487/RFC2119, March 1997, 494 . 496 [RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J., 497 and D. McPherson, "Dissemination of Flow Specification 498 Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009, 499 . 501 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 502 S. Ray, "North-Bound Distribution of Link-State and 503 Traffic Engineering (TE) Information Using BGP", RFC 7752, 504 DOI 10.17487/RFC7752, March 2016, 505 . 507 8.2. Informative References 509 [I-D.gredler-idr-bgp-ls-segment-routing-extension] 510 Gredler, H., Ray, S., Previdi, S., Filsfils, C., Chen, M., 511 and J. Tantsura, "BGP Link-State extensions for Segment 512 Routing", draft-gredler-idr-bgp-ls-segment-routing- 513 extension-02 (work in progress), October 2014. 515 [I-D.ietf-idr-bgpls-segment-routing-epe] 516 Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray, 517 S., and J. Dong, "BGP-LS extensions for Segment Routing 518 BGP Egress Peer Engineering", draft-ietf-idr-bgpls- 519 segment-routing-epe-17 (work in progress), October 2018. 521 Authors' Addresses 523 Nan Wu 524 Huawei 525 Huawei Bld., No.156 Beiqing Rd. 526 Beijing 100095 527 China 529 Email: eric.wu@huawei.com 531 Shunwan Zhuang 532 Huawei 533 Huawei Bld., No.156 Beiqing Rd. 534 Beijing 100095 535 China 537 Email: zhuangshunwan@huawei.com 539 Huaimo Chen 540 Huawei 541 Boston, MA 542 USA 544 Email: Huaimo.chen@huawei.com