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(The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (July 18, 2018) is 2106 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) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Open Shortest Path First IGP P. Psenak, Ed. 3 Internet-Draft K. Talaulikar 4 Intended status: Standards Track Cisco Systems, Inc. 5 Expires: January 19, 2019 W. Henderickx 6 Nokia 7 P. Pillay-Esnault 8 Huawei 9 July 18, 2018 11 OSPF LLS Extensions for Local Interface ID Advertisement 12 draft-ietf-ospf-lls-interface-id-05 14 Abstract 16 Every OSPF interface is assigned an identifier, Interface ID, which 17 uniquely identifies the interface on the router. In some cases it is 18 useful to know the Interface ID assigned by the adjacent router on 19 its side of the adjacency (Remote Interface ID). 21 This draft describes the extensions to OSPF link-local signalling to 22 advertise the Local Interface Identifier. 24 Requirements Language 26 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 27 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 28 "OPTIONAL" in this document are to be interpreted as described in 29 BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all 30 capitals, as shown here. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at https://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on January 19, 2019. 49 Copyright Notice 51 Copyright (c) 2018 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (https://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 67 2. Interface ID Exchange using TE Opaque LSA . . . . . . . . . . 3 68 3. Interface ID Exchange using OSPF LLS . . . . . . . . . . . . 3 69 3.1. Local Interface Identifier TLV . . . . . . . . . . . . . 3 70 4. Backward Compatibility with RFC 4203 . . . . . . . . . . . . 4 71 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 72 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 73 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5 74 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 75 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 76 9.1. Normative References . . . . . . . . . . . . . . . . . . 5 77 9.2. Informative References . . . . . . . . . . . . . . . . . 6 78 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 80 1. Introduction 82 Every OSPF interface is assigned an Interface ID, which uniquely 83 identifies the interface on the router. For example, some 84 implementations MAY be able to use the MIB-II IfIndex [RFC2863] as 85 the Interface ID. 87 Local/Remote Interface Identifiers MAY be flooded by OSPF [RFC2328] 88 as defined in [RFC4203]. From the perspective of the advertising 89 router, the Local Interface Identifier is a known value, however the 90 Remote Interface Identifier needs to be learnt before it can be 91 advertised. [RFC4203] suggests to use TE Link Local LSA [RFC3630] to 92 communicate the Local Interface Identifier to neighbors on the link. 93 Though such mechanism works, it has some drawbacks. 95 This draft proposes an extension to OSPF link-local signalling 96 [RFC5613] to advertise the Local Interface Identifier. 98 2. Interface ID Exchange using TE Opaque LSA 100 Usage of the Link Local TE Opaque LSA to propagate the Local 101 Interface Identifier to the neighbors on the link is described in 102 [RFC4203]. This mechanism has following problems: 104 LSAs can only be flooded over an existing adjacency that is in 105 Exchange state or greater. The adjacency state machine progresses 106 independently on each side of the adjacency and, as such, may 107 reach the Full state on one side before the TE Link Opaque LSA 108 arrives. The consequence is that link can be initially advertised 109 without the Remote Interface Identifier. Later, when the TE Link 110 Opaque LSA arrives, the link must be advertised again, this time 111 with the valid Remote Interface Identifier. Implementations may 112 choose to wait before advertising the link, but there is no 113 guarantee that the neighbor will ever advertise the TE Link Opaque 114 LSA with the Interface Identifier. In summary, the existing 115 mechanism does not guarantee that the Remote Interface Identifier 116 is known at the time the link is advertised. 118 The TE Opaque LSA is defined for MPLS Traffic Engineering, but the 119 knowledge of the Remote Interface Identifier is useful also for 120 cases where MPLS TE is not used. One example is the lack of a 121 valid 2-way connectivity check for parallel point-to-point links 122 between OSPF routers. 124 3. Interface ID Exchange using OSPF LLS 126 To address the problems described earlier and to allow the Interface 127 Identifier exchange to be part of the neighbor discovery process, we 128 propose to extend OSPF link-local signalling to advertise the Local 129 Interface Identifier in OSPF Hello packets. 131 3.1. Local Interface Identifier TLV 133 The Local Interface Identifier TLV is a LLS TLV. It has following 134 format: 136 0 1 2 3 137 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 1 138 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 139 | Type | Length | 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 | Local Interface Identifier | 142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 144 where: 146 Type: 18 148 Length: 4 octets 150 Local Interface Identifier: The value of the local Interface 151 Identifier. 153 Local Interface Identifier TLV signalling using LLS is applicable to 154 all OSPF interface types other than virtual links. 156 4. Backward Compatibility with RFC 4203 158 Implementations which support Local Interface ID signalling using LLS 159 MUST prefer the Local Interface ID value received through LLS over 160 the value received through Link Local TE Opaque LSA if both are 161 received from the same OSPF router. 163 Implementations which support Local Interface ID signalling via Link 164 Local TE Opaque LSA MAY continue to do so to ensure backward 165 compatibility. If they also support Local Interface ID signalling 166 using LLS as described herein, they SHOULD signal the same Local 167 Interface ID via both mechanisms. 169 During the rare conditions, when the Local Interface ID changes, a 170 timing interval may exist, where the received values of the Local 171 Interface ID advertised through LLS and Link Local TE Opaque LSA may 172 differ. Such situation is temporary and received values via both 173 mechanisms should become equal as soon as the next Hello and/or Link 174 Local TE Opaque LSA is re-generated by the originator. 176 5. IANA Considerations 178 This specification allocates a single code point from the "Open 179 Shortest Path First (OSPF) Link Local Signalling (LLS) - Type/Length/ 180 Value Identifiers (TLV)" registry. 182 Following values is allocated: 184 o 18 - Local Interface Identifier TLV 186 6. Security Considerations 188 The security considerations for "OSPF Link-Local Signaling" [RFC5613] 189 also apply to the Local Interface Identifier TLV described herein. 190 The current usage of a neighbor's Local Interface Identifier is to 191 disambiguate parallel links between OSPF routers. Hence, 192 modification of the advertised Local Interface Identifier TLV may 193 result in the wrong neighbor interface identifier being advertised in 194 the OSPFv2 Extended Link LSA [RFC8379] and could prevent the link 195 from being used. If authentication is being used in the OSPF routing 196 domain [RFC5709], then the Cryptographic Authentication TLV [RFC5613] 197 SHOULD also be used to protect that contents of the Link-Local 198 Signaling (LLS) block. 200 Implementations must assure that malformed LLS TLVs and Sub-TLVs 201 permutations do not result in errors which cause hard OSPF failures. 203 7. Contributors 205 8. Acknowledgements 207 Thanks to Tony Przygienda for his extensive review and useful 208 comments. 210 9. References 212 9.1. Normative References 214 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 215 Requirement Levels", BCP 14, RFC 2119, 216 DOI 10.17487/RFC2119, March 1997, 217 . 219 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 220 DOI 10.17487/RFC2328, April 1998, 221 . 223 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 224 (TE) Extensions to OSPF Version 2", RFC 3630, 225 DOI 10.17487/RFC3630, September 2003, 226 . 228 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 229 Support of Generalized Multi-Protocol Label Switching 230 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 231 . 233 [RFC5613] Zinin, A., Roy, A., Nguyen, L., Friedman, B., and D. 234 Yeung, "OSPF Link-Local Signaling", RFC 5613, 235 DOI 10.17487/RFC5613, August 2009, 236 . 238 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 239 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 240 May 2017, . 242 9.2. Informative References 244 [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group 245 MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, 246 . 248 [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., 249 Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic 250 Authentication", RFC 5709, DOI 10.17487/RFC5709, October 251 2009, . 253 [RFC8379] Hegde, S., Sarkar, P., Gredler, H., Nanduri, M., and L. 254 Jalil, "OSPF Graceful Link Shutdown", RFC 8379, 255 DOI 10.17487/RFC8379, May 2018, 256 . 258 Authors' Addresses 260 Peter Psenak (editor) 261 Cisco Systems, Inc. 262 Apollo Business Center 263 Mlynske nivy 43 264 Bratislava 821 09 265 Slovakia 267 Email: ppsenak@cisco.com 269 Ketan Jivan Talaulikar 270 Cisco Systems, Inc. 271 S.No. 154/6, Phase I, Hinjawadi 272 PUNE, MAHARASHTRA 411 057 273 India 275 Email: ketant@cisco.com 277 Wim Henderickx 278 Nokia 279 Copernicuslaan 50 280 Antwerp 2018 281 BE 283 Email: wim.henderickx@nokia.com 284 Padma Pillay-Esnault 285 Huawei 286 2330 Central Expressway 287 Santa Clara, CA 95050 288 USA 290 Email: padma@huawei.com