idnits 2.17.1 draft-acee-lsr-ospf-admin-tags-05.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (July 13, 2020) is 1355 days in the past. Is this intentional? 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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-16) exists of draft-ietf-ospf-te-link-attr-reuse-10 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Lindem, Ed. 3 Internet-Draft P. Psenak 4 Intended status: Standards Track Cisco Systems 5 Expires: January 14, 2021 July 13, 2020 7 Extensions to OSPF for Advertising Prefix Administrative Tags 8 draft-acee-lsr-ospf-admin-tags-05 10 Abstract 12 It is useful for routers in an OSPFv2 or OSPFv3 routing domain to be 13 able to associate tags with prefixes. Previously, OSPFv2 and OSPFv3 14 were relegated to a single tag for AS External and Not-So-Stubby-Area 15 (NSSA) prefixes. With the flexible encodings provided by OSPFv2 16 Prefix Attribute Advertisement and OSPFv3 Extended LSAs, multiple 17 administrative tags may advertised for all types of prefixes. These 18 administrative tags can be used for many applications including route 19 redistribution policy, selective prefix prioritization, selective IP 20 Fast-ReRoute (IPFRR) prefix protection, and many others. 22 The ISIS protocol supports a similar mechanism that is described in 23 RFC 5130. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on January 14, 2021. 42 Copyright Notice 44 Copyright (c) 2020 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 61 1.1.1. Requirements Language . . . . . . . . . . . . . . . . 3 62 2. 32-Bit Administrative Tag Sub-TLV . . . . . . . . . . . . . . 3 63 3. Administrative Tag Applicability . . . . . . . . . . . . . . 4 64 4. Protocol Operation . . . . . . . . . . . . . . . . . . . . . 5 65 4.1. Equal-Cost Multipath Applicability . . . . . . . . . . . 5 66 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 67 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 68 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 69 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 70 8.1. Normative References . . . . . . . . . . . . . . . . . . 6 71 8.2. Informative References . . . . . . . . . . . . . . . . . 7 72 Appendix A. 64-Bit Administrative Tag Sub-TLV . . . . . . . . . 7 73 Appendix B. Link Administrative Tags . . . . . . . . . . . . . . 8 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 76 1. Introduction 78 It is useful for routers in an OSPFv2 [RFC2328] or OSPFv3 [RFC5340] 79 routing domain to be able to associate tags with prefixes. 80 Previously, OSPFv3 and OSPFv3 were relegated to a single tag for AS 81 External and Not-So-Stubby-Area (NSSA) prefixes. With the flexible 82 encodings provided by OSPFv2 Prefix Attribute Advertisement 83 ([RFC7684]) and OSPFv3 Extended LSA ([RFC8362]), multiple 84 administrative tags may be advertised for all types of prefixes. 85 These administrative tags can be used many applications including 86 (but not limited to): 88 1. Controlling which routes are redistributed into other protocols 89 for readvertisement. 91 2. Prioritizing selected prefixes for faster convergence and 92 installation in the forwarding plane. 94 3. Identifying selected prefixes for Loop-Free Alternative (LFA) 95 protection. 97 Throughout this document, OSPF is used when the text applies to both 98 OSPFv2 and OSPFv3. OSPFv2 or OSPFv3 is used when the text is 99 specific to one version of the OSPF protocol. 101 The ISIS protocol supports a similar mechanism that is described in 102 RFC 5130 [RFC5130]. 104 1.1. Requirements notation 106 1.1.1. Requirements Language 108 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 109 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 110 "OPTIONAL" in this document are to be interpreted as described in BCP 111 14 [RFC2119] [RFC8174] when, and only when, they appear in all 112 capitals, as shown here. 114 2. 32-Bit Administrative Tag Sub-TLV 116 This document creates a new Administrative Tag Sub-TLV for OSPFv2 and 117 OSPFv3. This Sub-TLV specifies one or more 32-bit unsigned integers 118 that may be associated with an OSPF advertised prefix. The precise 119 usage of these tags is beyond the scope of this document. 121 The format of this Sub-TLV is the same as the format used by the 122 Traffic Engineering Extensions to OSPF [RFC3630]. The LSA payload 123 consists of one or more nested Type/Length/Value (TLV) triplets. The 124 format of each TLV is: 126 0 1 2 3 127 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 1 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | Type | Length | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 | Value... | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 TLV Format 136 The Length field defines the length of the value portion in octets 137 (thus a TLV with no value portion would have a length of 0). The TLV 138 is padded to 4-octet alignment; padding is not included in the length 139 field (so a 3-octet value would have a length of 3, but the total 140 size of the TLV would be 8 octets). 142 The format of the 32-bit Administrative Tag TLV is as follows: 144 0 1 2 3 145 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 1 146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 147 | Type | Length | 148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 149 | First 32-bit Administrative Tag | 150 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 151 | o | 152 o 153 | o | 154 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 155 | Last 32-bit Administrative Tag | 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 Type A 16-bit field set to TBD. The value MAY be different 159 depending upon the IANA registry from which it is 160 allocated. 162 Length A 16-bit field that indicates the length of the value 163 portion in octets and will be a multiple of 4 octets 164 dependent on the number of administrative tags 165 advertised. If the sub-TLV is specified, at least one 166 administrative tag must be advertised. 168 Value A variable length list of one or more administrative 169 tags. 171 32-bit Administrative Tag Sub-TLV 173 This sub-TLV will carry one or more 32-bit unsigned integer values 174 that will be used as administrative tags. 176 3. Administrative Tag Applicability 178 The administrative tag TLV specified herein will be valid as a sub- 179 TLV of the following TLVs specified in [RFC7684]: 181 1. Extended Prefix TLV advertised in the OSPFv2 Extended Prefix LSA 183 The administrative tag TLV specified herein will be valid as a sub- 184 TLV of the following TLVs specified in [RFC8362]: 186 1. Inter-Area-Prefix TLV advertised in the E-Inter-Area-Prefix-LSA 188 2. Intra-Area-Prefix TLV advertised in the E-Link-LSA and the E- 189 Intra-Area-LSA 191 3. External-Prefix TLV advertised in the E-AS-External-LSA and the 192 E-NSSA-LSA 194 4. Protocol Operation 196 An OSPF router supporting this specification MUST propagate 197 administrative tags when acting as an Area Border Router and 198 originating summary advertisements into other areas. Similarly, an 199 OSPF router supporting this specification and acting as an ABR for a 200 Not-So-Stubby Area (NSSA) MUST propagate tags when translating NSSA 201 routes to AS External advertisements [RFC3101]. The number of tags 202 supported MAY limit the number of tags that are propagated. When 203 propagating multiple tags, the order of the the tags must be 204 preserved. 206 For configured area ranges, NSSA ranges, and configurated 207 summarization of redistributed routes, tags from component routes 208 SHOULD NOT be propagated to the summary. Implementations SHOULD 209 provide a mechanism to configure tags for area ranges, NSSA ranges, 210 and redistributed route summaries. 212 An OSPF router supporting this specification MUST be able to 213 advertise and interpret one 32-bit tag for prefixes. An OSPF router 214 supporting this specification MAY be able to advertise and propagate 215 multiple 32-bit tags. The maximum tags that an implementation 216 supports is a local matter depending upon supported applications 217 using the prefix tags. 219 When a single tag is advertised for AS External or NSSA LSA prefix, 220 the existing tag in OSPFv2 and OSPFv3 AS-External-LSA and NSSA-LSA 221 encodings SHOULD be utilized. This will facilitate backward 222 compatibilty with implementations that do not support this 223 specification. 225 4.1. Equal-Cost Multipath Applicability 227 When multiple LSAs contribute to an OSPF route, it is possible that 228 these LSAs will all have different tags. In this situation, the OSPF 229 router MUST associate the tags from one of the LSAs contributing a 230 path and, if the implementation supports multiple tags, MAY associate 231 tags for multiple contributing LSAs up to the maximum number of tags 232 supported. 234 5. Security Considerations 236 This document describes both a generic mechanism for advertising 237 administrative tags for OSPF prefixes. The administrative tags are 238 generally less critical than the topology information currently 239 advertised by the base OSPF protocol. The security considerations 240 for the generic mechanism are dependent on the future application 241 and, as such, should be described as additional capabilities are 242 proposed for advertisement. Security considerations for the base 243 OSPF protocol are covered in [RFC2328] and [RFC5340]. 245 6. IANA Considerations 247 The following values should be allocated from the OSPF Extended 248 Prefix TLV Sub-TLV Registry [RFC7684]: 250 o TBD - 32-bit Administrative Tag TLV 252 The following values should be allocated from the OSPFv3 Extended-LSA 253 Sub-TLV Registry [RFC8362]: 255 o TBD - 32-bit Administrative Tag TLV 257 7. Acknowledgments 259 The authors of RFC 5130 are acknowledged since this document draws 260 upon both the ISIS specification and deployment experience. 262 Thanks to Donnie Savage for his comments and questions. 264 The RFC text was produced using Marshall Rose's xml2rfc tool. 266 8. References 268 8.1. Normative References 270 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 271 Requirement Levels", BCP 14, RFC 2119, 272 DOI 10.17487/RFC2119, March 1997, 273 . 275 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 276 DOI 10.17487/RFC2328, April 1998, 277 . 279 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 280 (TE) Extensions to OSPF Version 2", RFC 3630, 281 DOI 10.17487/RFC3630, September 2003, 282 . 284 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 285 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 286 . 288 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 289 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 290 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 291 2015, . 293 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 294 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 295 May 2017, . 297 [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and 298 F. Baker, "OSPFv3 Link State Advertisement (LSA) 299 Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 300 2018, . 302 8.2. Informative References 304 [I-D.ietf-ospf-te-link-attr-reuse] 305 Psenak, P., Ginsberg, L., Henderickx, W., Tantsura, J., 306 and J. Drake, "OSPF Link Traffic Engineering Attribute 307 Reuse", draft-ietf-ospf-te-link-attr-reuse-10 (work in 308 progress), October 2019. 310 [RFC3101] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option", 311 RFC 3101, DOI 10.17487/RFC3101, January 2003, 312 . 314 [RFC5130] Previdi, S., Shand, M., Ed., and C. Martin, "A Policy 315 Control Mechanism in IS-IS Using Administrative Tags", 316 RFC 5130, DOI 10.17487/RFC5130, February 2008, 317 . 319 Appendix A. 64-Bit Administrative Tag Sub-TLV 321 The definition of the 64-bit tag was considered but discard given 322 that there is no strong requirement or use case. The specification 323 is included here for information. 325 This sub-TLV will carry one or more 64-bit unsigned integer values 326 that will be used as administrative tags. 328 The format of the 64-bit Administrative Tag TLV is as follows: 330 0 1 2 3 331 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 1 332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 333 | Type | Length | 334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 335 | First 64-bit Administrative Tag | 336 | | 337 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 338 | o | 339 o 340 | o | 341 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 342 | Last 64-bit Administrative Tag | 343 | | 344 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 346 Type A 16-bit field set to TBD. The value MAY be different 347 depending upon the registry from which it is allocated. 349 Length A 16-bit field that indicates the length of the value 350 portion in octets and will be a multiple of 8 octets 351 dependent on the number of administrative tags 352 advertised. If the sub-TLV is specified, at least one 353 administrative tag must be advertised. 355 Value A variable length list of one or more 64-bit 356 administrative tags. 358 64-bit Administrative Tag TLV 360 Appendix B. Link Administrative Tags 362 The advertisement of administrative tags corresponding to links has 363 been removed from the document. The specification of advertising 364 link administrative groups as specified in 365 [I-D.ietf-ospf-te-link-attr-reuse] satisfies the same requirement as 366 advertising administrative tags for links. 368 Authors' Addresses 370 Acee Lindem (editor) 371 Cisco Systems 372 301 Midenhall Way 373 Cary, NC 27513 374 USA 376 Email: acee@cisco.com 377 Peter Psenak 378 Cisco Systems 379 Apollo Business Center 380 Mlynske nivy 43 381 Bratislava, 821 09 382 Slovakia 384 Email: ppsenak@cisco.com