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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-14) exists of draft-ietf-idr-bgpls-srv6-ext-08 == Outdated reference: A later version (-09) exists of draft-ietf-spring-sr-service-programming-04 ** Obsolete normative reference: RFC 7752 (Obsoleted by RFC 9552) == Outdated reference: A later version (-26) exists of draft-ietf-idr-segment-routing-te-policy-13 == Outdated reference: A later version (-22) exists of draft-ietf-spring-segment-routing-policy-13 Summary: 1 error (**), 0 flaws (~~), 5 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Inter-Domain Routing G. Dawra, Ed. 3 Internet-Draft LinkedIn 4 Intended status: Standards Track C. Filsfils 5 Expires: February 18, 2022 K. Talaulikar, Ed. 6 F. Clad 7 Cisco Systems 8 D. Bernier 9 Bell Canada 10 J. Uttaro 11 AT&T 12 B. Decraene 13 Orange 14 H. Elmalky 15 Ericsson 16 X. Xu 17 Capitalonline 18 J. Guichard 19 Futurewei Technologies 20 C. Li 21 Huawei Technologies 22 August 17, 2021 24 BGP-LS Advertisement of Segment Routing Service Segments 25 draft-dawra-idr-bgp-ls-sr-service-segments-06 27 Abstract 29 Service functions are deployed as, physical or virtualized elements 30 along with network nodes or on servers in data centers. Segment 31 Routing (SR) brings in the concept of segments which can be 32 topological or service instructions. Service segments are SR 33 segments that are associated with service functions. SR Policies are 34 used for the setup of paths for steering of traffic through service 35 functions using their service segments. 37 BGP Link-State (BGP-LS) enables distribution of topology information 38 from the network to a controller or an application in general so it 39 can learn the network topology. This document specifies the 40 extensions to BGP-LS for the advertisement of service functions along 41 their associated service segments. The BGP-LS advertisement of 42 service function information along with the network nodes that they 43 are attached to, or associated with, enables controllers compute and 44 setup service paths in the network. 46 Status of This Memo 48 This Internet-Draft is submitted in full conformance with the 49 provisions of BCP 78 and BCP 79. 51 Internet-Drafts are working documents of the Internet Engineering 52 Task Force (IETF). Note that other groups may also distribute 53 working documents as Internet-Drafts. The list of current Internet- 54 Drafts is at https://datatracker.ietf.org/drafts/current/. 56 Internet-Drafts are draft documents valid for a maximum of six months 57 and may be updated, replaced, or obsoleted by other documents at any 58 time. It is inappropriate to use Internet-Drafts as reference 59 material or to cite them other than as "work in progress." 61 This Internet-Draft will expire on February 18, 2022. 63 Copyright Notice 65 Copyright (c) 2021 IETF Trust and the persons identified as the 66 document authors. All rights reserved. 68 This document is subject to BCP 78 and the IETF Trust's Legal 69 Provisions Relating to IETF Documents 70 (https://trustee.ietf.org/license-info) in effect on the date of 71 publication of this document. Please review these documents 72 carefully, as they describe your rights and restrictions with respect 73 to this document. Code Components extracted from this document must 74 include Simplified BSD License text as described in Section 4.e of 75 the Trust Legal Provisions and are provided without warranty as 76 described in the Simplified BSD License. 78 Table of Contents 80 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 81 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 82 2. BGP-LS Extensions for Service Chaining . . . . . . . . . . . 4 83 3. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 7 84 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 85 4.1. Service Type Table . . . . . . . . . . . . . . . . . . . 7 86 4.2. Segment routing function Identifier(SFI) . . . . . . . . 8 87 5. Manageability Considerations . . . . . . . . . . . . . . . . 8 88 6. Operational Considerations . . . . . . . . . . . . . . . . . 8 89 6.1. Operations . . . . . . . . . . . . . . . . . . . . . . . 9 90 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 91 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 92 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 93 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 94 9.2. Informative References . . . . . . . . . . . . . . . . . 10 95 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 97 1. Introduction 99 Segments are introduced in the SR architecture [RFC8402]. Segment 100 Routing based Service chaining is well described in 101 [I-D.ietf-spring-sr-service-programming] with an example of network 102 and services. 104 This document extend the example to add a Segment Routing Controller 105 (SR-C) to the network, for the purpose of service discovery and SR 106 policy [I-D.ietf-spring-segment-routing-policy] instantiation. 108 Consider the network represented in Figure 1 below where: 110 o A and B are two end hosts using IPv4. 112 o S1 is an SR-aware firewall Service. 114 o S2 is an SR-unaware DPI Service. 116 SR-C --3-- 117 | / \ 118 | / \ 119 A----1----2----4----5----6----B 120 | | 121 | | 122 S1 S2 124 Figure 1: Network with Services 126 SR Controller (SR-C) is connected to Node 1, but may be attached to 127 any node 1-6 in the network. 129 SR-C can receive BGP-LS updates to discover topology, and calculate 130 constrained paths between nodes 1 and 6. 132 However, if SR-C is configured to compute a constrained path from 1 133 and 6, including a DPI service (i.e., S2) it is not yet possible due 134 to the lack of service distribution. SR-C does not know where a DPI 135 service is nor the SID for it. It does not know that S2 is a service 136 it needs. 138 This document proposes an extension to BGP-LS for Service Chaining to 139 distribute the service information to SR-C. There may be other 140 alternate mechanisms to distribute service information to SR-C and 141 are outside the scope of this document. There are no extensions 142 required in SR-TE Policy SAFI. 144 1.1. Requirements Language 146 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 147 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 148 "OPTIONAL" in this document are to be interpreted as described in BCP 149 14 [RFC2119] [RFC8174] when, and only when, they appear in all 150 capitals, as shown here. 152 2. BGP-LS Extensions for Service Chaining 154 For an attached service, following data needs to be shared with SR-C: 156 o Service SID value (e.g. MPLS label or IPv6 address). Service SID 157 MAY only be encoded as LOC:FUNCT, where LOC is the L most 158 significant bits and FUNCT is the 128-L least significant 159 bits[RFC8986]. ARGs bits, if any, MAY be set to 0 in the 160 advertised service SID. 162 o Function Identifier (Static Proxy, Dynamic Proxy, Shared Memory 163 Proxy, Masquerading Proxy, SR Aware Service etc.). 165 o Service Type (DPI, Firewall, Classifier, LB etc.). 167 o Traffic Type (IPv4 OR IPv6 OR Ethernet) 169 o Opaque Data (Such as brand and version, other extra information) 171 [I-D.ietf-spring-sr-service-programming] defines SR-aware and SR- 172 unaware services. This document will reuse these definitions. Per 173 [RFC7752] Node Attributes are ONLY associated with the Node NLRI. 174 All non-VPN information SHALL be encoded using AFI 16388 / SAFI 71. 175 VPN information SHALL be encoded using AFI 16388 / SAFI 72 with 176 associated RTs. 178 This document introduces new TLVs for the SRv6 SID NLRI 179 [I-D.ietf-idr-bgpls-srv6-ext] and SR-MPLS SID/Label TLV [RFC9085] to 180 associate the Service SID value with Service-related Information 181 using Service Chaining(SC) Sub-TLV. 183 SRv6 SID Information TLV [I-D.ietf-idr-bgpls-srv6-ext] encodes 184 behavior along with associated SID Flags. 186 A Service Chaining (SC) TLV in Figure 2 is defined as: 188 +---------------------------------------+ 189 | Type (2 octet) | 190 +---------------------------------------+ 191 | Length (2 octet) | 192 +---------------------------------------+ 193 | Service Type(ST) (2 octet | 194 +---------------------------------------+ 195 | Flags (1 octet) | 196 +---------------------------------------+ 197 | Traffic Type(1 octet) | 198 +---------------------------------------+ 199 | RESERVED (2 octet) | 200 +---------------------------------------+ 202 Figure 2: Service Chaining (SC) TLV 204 Where: 206 Type: 16 bit field. TBD 208 Length: 16 bit field. The total length of the value portion of 209 the TLV. 211 Service Type(ST): 16bit field. Service Type: categorizes the 212 Service: (such as "Firewall", "Classifier" etc.). 214 Flags: 8 bit field. Bits SHOULD be 0 on transmission and MUST be 215 ignored on reception. 217 Traffic Type: 8 Bit field. A bit to identify if Service is IPv4 218 OR IPv6 OR L2 Ethernet Capable. Where: 220 Bit 0(LSB): Set to 1 if Service is IPv4 Capable 222 Bit 1: Set to 1 if Service is IPv6 Capable 224 Bit 2: Set to 1 if Service is Ethernet Capable 226 RESERVED: 16bit field. SHOULD be 0 on transmission and MUST be 227 ignored on reception. 229 Service Type(ST) MUST be encoded as part of SC TLV. 231 There may be multiple instances of similar Services that need to be 232 distinguished. For example, firewalls made by different vendors A 233 and B may need to be identified differently because, while they have 234 similar functionality, their behavior is not identical. 236 In order for the SDN Controller to identify the categories of 237 Services and their associated SIDs, this section defines the BGP-LS 238 extensions required to encode these characteristics and other 239 relevant information about these Services. 241 Another Optional Opaque Metadata(OM) TLV of SRv6 SID NLRI may encode 242 vendor specific information. Multiple of OM TLVs may be encoded. 244 +---------------------------------------+ 245 | Type (2 octet) | 246 +---------------------------------------+ 247 | Length (2 octet) | 248 +---------------------------------------+ 249 | Opaque Type (2 octet) | 250 +---------------------------------------+ 251 | Flags (1 octet) | 252 +---------------------------------------+ 253 | Value (variable) | 254 +---------------------------------------+ 256 Figure 3: Opaque Metadata(OM) TLV 258 o Type: 16 bit field. TBD. 260 o Length: 16 bit field. The total length of the value portion of 261 the TLV. 263 o Opaque Type: 8-bit field. Only publishers and consumers of the 264 opaque data are supposed to understand the data. 266 o Flags: 8 bit field. Bits SHOULD be 0 on transmission and MUST be 267 ignored on reception. 269 o Value: Variable Length. Based on the data being encoded and 270 length is recorded in length field. 272 Opaque Metadata(OM) TLV defined in Figure 3 may encode propriety or 273 Service Opaque information such as: 275 o Vendor specific Service Information. 277 o Traffic Limiting Information to particular Service Type. 279 o Opaque Information unique to the Service. 281 o Propriety Enterprise Service specific Information. 283 3. Illustration 285 In our SRv6 example above Figure 1, Node 5 is configured with an SRv6 286 dynamic proxy segments (End.AD) C5::AD:F2 for S2. 288 The BGP-LS advertisement MUST include SRv6 SID NLRI with SRv6 SID 289 Information TLV in the BGP-LS Attribute: 291 o Service SID: C5::AD:F2 SID 293 o Endpoint Behavior: END.AD 295 The BGP-LS Attribute MUST contain a SC TLV with: 297 o Service Type: Deep Packet Inspection(DPI) 299 o Traffic Type: IPv4 Capable. 301 The BGP-LS Attribute MAY contain a OM TLV with: 303 o Opaque Type: Cisco DPI Version 305 o Value: 3.5 307 In our example in Figure 1, using BGP SR-TE SAFI Update 308 [I-D.ietf-idr-segment-routing-te-policy], SR Controller computes the 309 candidate path and pushes the Policy. 311 SRv6 encapsulation policy < CF1::, C3::, C5::AD:F2, C6::D4:B > is 312 signaled to Node 1 which has mix of service and topological segments. 314 4. IANA Considerations 316 This document requests assigning code-points from the registry "BGP- 317 LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute 318 TLVs". 320 4.1. Service Type Table 322 IANA is request to create a new top-level registry called "Service 323 Type Table (STT)". Valid values are in the range 0 to 65535. Values 324 0 and 65535 are to be marked "Reserved, not to be allocated". 326 +------------+-----------------------+------------+-------------+ 327 | Service | Service | Reference | Date | 328 | Value(TBD) | | | | 329 +------------+-----------------------+------------+-------------+ 330 | 32 | Classifier | ref-to-set | date-to-set | 331 +------------+-----------------------+------------+-------------+ 332 | 33 | Firewall | ref-to-set | date-to-set | 333 +------------+-----------------------+------------+-------------+ 334 | 34 | Load Balancer | ref-to-set | date-to-set | 335 +------------+-----------------------+------------+-------------+ 336 | 35 | DPI | ref-to-set | date-to-set | 337 +------------+-----------------------+------------+-------------+ 339 Figure 4 341 4.2. Segment routing function Identifier(SFI) 343 IANA is request to extend a top-level registry called "Segment 344 Routing Function Identifier(SFI)" with new code points. This 345 document extends the SFI values defined in 346 [I-D.ietf-idr-bgpls-srv6-ext]. Details about the Service functions 347 are defined in[I-D.ietf-spring-sr-service-programming]. 349 +--------------------------+---------------------------+ 350 | Function | Function Identifier | 351 | | | 352 +--------------------------+---------------------------+ 353 | Static Proxy | 8 | 354 +--------------------------+---------------------------+ 355 | Dynamic Proxy | 9 | 356 +--------------------------+---------------------------+ 357 | Shared Memory Proxy | 10 | 358 +--------------------------+---------------------------+ 359 | Masquerading Proxy | 11 | 360 +--------------------------+---------------------------+ 361 | SRv6 Aware Service | 12 | 362 +--------------------------+---------------------------+ 364 5. Manageability Considerations 366 This section is structured as recommended in[RFC5706] 368 6. Operational Considerations 369 6.1. Operations 371 Existing BGP and BGP-LS operational procedures apply. No additional 372 operation procedures are defined in this document. 374 7. Security Considerations 376 Procedures and protocol extensions defined in this document do not 377 affect the BGP security model. See the 'Security Considerations' 378 section of [RFC4271] for a discussion of BGP security. Also refer 379 to[RFC4272] and[RFC6952] for analysis of security issues for BGP. 381 8. Acknowledgements 383 The authors would like to thank Krishnaswamy Ananthamurthy for his 384 review of this document. 386 9. References 388 9.1. Normative References 390 [I-D.ietf-idr-bgpls-srv6-ext] 391 Dawra, G., Filsfils, C., Talaulikar, K., Chen, M., 392 Bernier, D., and B. Decraene, "BGP Link State Extensions 393 for SRv6", draft-ietf-idr-bgpls-srv6-ext-08 (work in 394 progress), June 2021. 396 [I-D.ietf-spring-sr-service-programming] 397 Clad, F., Xu, X., Filsfils, C., Bernier, D., Li, C., 398 Decraene, B., Ma, S., Yadlapalli, C., Henderickx, W., and 399 S. Salsano, "Service Programming with Segment Routing", 400 draft-ietf-spring-sr-service-programming-04 (work in 401 progress), March 2021. 403 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 404 Requirement Levels", BCP 14, RFC 2119, 405 DOI 10.17487/RFC2119, March 1997, 406 . 408 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 409 S. Ray, "North-Bound Distribution of Link-State and 410 Traffic Engineering (TE) Information Using BGP", RFC 7752, 411 DOI 10.17487/RFC7752, March 2016, 412 . 414 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 415 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 416 May 2017, . 418 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 419 Decraene, B., Litkowski, S., and R. Shakir, "Segment 420 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 421 July 2018, . 423 [RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer, 424 D., Matsushima, S., and Z. Li, "Segment Routing over IPv6 425 (SRv6) Network Programming", RFC 8986, 426 DOI 10.17487/RFC8986, February 2021, 427 . 429 [RFC9085] Previdi, S., Talaulikar, K., Ed., Filsfils, C., Gredler, 430 H., and M. Chen, "Border Gateway Protocol - Link State 431 (BGP-LS) Extensions for Segment Routing", RFC 9085, 432 DOI 10.17487/RFC9085, August 2021, 433 . 435 9.2. Informative References 437 [I-D.ietf-idr-segment-routing-te-policy] 438 Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., 439 Rosen, E., Jain, D., and S. Lin, "Advertising Segment 440 Routing Policies in BGP", draft-ietf-idr-segment-routing- 441 te-policy-13 (work in progress), June 2021. 443 [I-D.ietf-spring-segment-routing-policy] 444 Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and 445 P. Mattes, "Segment Routing Policy Architecture", draft- 446 ietf-spring-segment-routing-policy-13 (work in progress), 447 May 2021. 449 [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A 450 Border Gateway Protocol 4 (BGP-4)", RFC 4271, 451 DOI 10.17487/RFC4271, January 2006, 452 . 454 [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", 455 RFC 4272, DOI 10.17487/RFC4272, January 2006, 456 . 458 [RFC5706] Harrington, D., "Guidelines for Considering Operations and 459 Management of New Protocols and Protocol Extensions", 460 RFC 5706, DOI 10.17487/RFC5706, November 2009, 461 . 463 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 464 BGP, LDP, PCEP, and MSDP Issues According to the Keying 465 and Authentication for Routing Protocols (KARP) Design 466 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 467 . 469 Authors' Addresses 471 Gaurav Dawra (editor) 472 LinkedIn 473 USA 475 Email: gdawra.ietf@gmail.com 477 Clarence Filsfils 478 Cisco Systems 479 Belgium 481 Email: cfilsfil@cisco.com 483 Ketan Talaulikar (editor) 484 Cisco Systems 485 India 487 Email: ketant@cisco.com 489 Francois Clad 490 Cisco Systems 491 France 493 Email: fclad@cisco.com 495 Daniel Bernier 496 Bell Canada 497 Canada 499 Email: daniel.bernier@bell.ca 501 Jim Uttaro 502 AT&T 503 USA 505 Email: ju1738@att.com 506 Bruno Decraene 507 Orange 508 France 510 Email: bruno.decraene@orange.com 512 Hani Elmalky 513 Ericsson 514 USA 516 Email: hani.elmalky@gmail.com 518 Xiaohu Xu 519 Capitalonline 521 Email: xiaohu.xu@capitalonline.net 523 Jim Guichard 524 Futurewei Technologies 525 USA 527 Email: james.n.guichard@futurewei.com 529 Cheng Li 530 Huawei Technologies 531 China 533 Email: chengli13@huawei.com