idnits 2.17.1 draft-ietf-ospf-lls-interface-id-09.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 seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords -- however, there's a paragraph with a matching beginning. Boilerplate error? (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (November 4, 2018) is 1993 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: May 8, 2019 W. Henderickx 6 Nokia 7 P. Pillay-Esnault 8 Huawei 9 November 4, 2018 11 OSPF LLS Extensions for Local Interface ID Advertisement 12 draft-ietf-ospf-lls-interface-id-09 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 assigned Interface ID on the remote side of the 19 adjacency (Remote Interface ID). 21 This draft describes the extensions to OSPF link-local signalling 22 (LLS) to 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 May 8, 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 1.1. Interface ID Exchange using TE Opaque LSA . . . . . . . . 3 68 2. Interface ID Exchange using OSPF LLS . . . . . . . . . . . . 3 69 2.1. Local Interface Identifier TLV . . . . . . . . . . . . . 4 70 3. Backward Compatibility with RFC 4203 . . . . . . . . . . . . 4 71 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 72 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 73 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 74 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 75 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 76 7.2. Informative References . . . . . . . . . . . . . . . . . 6 77 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 79 1. Introduction 81 Every OSPF interface is assigned an Interface ID, which uniquely 82 identifies the interface on the router. [RFC2328] uses this 83 Interface ID in the Router-LSA Link Data for unnumbered links and 84 uses the value of the MIB-II IfIndex [RFC2863]. [RFC4203] refers to 85 these Interface IDs as the Link Local/Remote Identifiers and defines 86 a way to advertise and use them for Generalized Multi-Protocol Label 87 Switching (GMPLS) purposes. [RFC7684] defines a way to advertise 88 Local/Remote Interface IDs in the OSPFv2 Extended Link LSA. 90 There is a known OSPFv2 protocol problem in verifying the bi- 91 directional connectivity with parallel unnumbered links. If there 92 are two parallel unnumbered links between a pair of routers and each 93 link is only advertised from single direction, such two 94 unidirectional parallel links could be considered as a valid single 95 bidirectional link during the OSPF route computation on some other 96 router. If each link is advertised with both its Local and Remote 97 Interface IDs, the advertisement of each link from both sides of 98 adjacency can be verified by cross-checking the Local and Remote 99 Interface IDs of both advertisements. 101 From the perspective of the advertising router, the Local Interface 102 Identifier is a known value, however the Remote Interface Identifier 103 needs to be learnt before it can be advertised. [RFC4203] suggests 104 to use TE Link Local LSA [RFC3630] to communicate the Local Interface 105 Identifier to neighbors on the link. Though such mechanism works, it 106 has some drawbacks. 108 This draft proposes an extension to OSPF link-local signalling (LLS) 109 [RFC5613] to advertise the Local Interface Identifier. 111 1.1. Interface ID Exchange using TE Opaque LSA 113 Usage of the Link Local TE Opaque LSA to propagate the Local 114 Interface Identifier to the neighbors on the link is described in 115 [RFC4203]. This mechanism has the following problems: 117 LSAs can only be flooded over an existing adjacency that is in 118 Exchange state or greater. The adjacency state machine progresses 119 independently on each side of the adjacency and, as such, may 120 reach the Full state on one side before the TE Link Opaque LSA 121 arrives. The consequence is that link can be initially advertised 122 without the Remote Interface Identifier. Later, when the TE Link 123 Opaque LSA arrives, the link must be advertised again, this time 124 with the valid Remote Interface Identifier. Implementations may 125 choose to wait before advertising the link, but there is no 126 guarantee that the neighbor will ever advertise the TE Link Opaque 127 LSA with the Interface Identifier. In summary, the existing 128 mechanism does not guarantee that the Remote Interface Identifier 129 is known at the time the link is advertised. 131 The TE Opaque LSA is defined for MPLS Traffic Engineering, but the 132 knowledge of the Remote Interface Identifier is useful also for 133 cases where MPLS TE is not used. One example is the mentioned 134 lack of a valid 2-way connectivity check for parallel point-to- 135 point links between OSPF routers. 137 2. Interface ID Exchange using OSPF LLS 139 To address the problems described earlier and to allow the Interface 140 Identifier exchange to be part of the neighbor discovery process, we 141 propose to extend OSPF link-local signalling to advertise the Local 142 Interface Identifier in OSPF Hello and Database Description (DD) 143 packets. 145 2.1. Local Interface Identifier TLV 147 The Local Interface Identifier TLV is a LLS TLV. It has following 148 format: 150 0 1 2 3 151 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 1 152 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 153 | Type | Length | 154 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 155 | Local Interface Identifier | 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 where: 160 Type: TBD 162 Length: 4 octets 164 Local Interface Identifier: The value of the local Interface 165 Identifier. 167 Local Interface Identifier TLV signalling using LLS is applicable to 168 all OSPF interface types other than virtual links. 170 3. Backward Compatibility with RFC 4203 172 If the Local Interface ID signaling via Link Local TE Opaque LSA is 173 supported in addition to the new LLS mechanism, implementations which 174 support Local Interface ID signalling using LLS MUST prefer the Local 175 Interface ID value received through LLS over the value received 176 through the Link Local TE Opaque LSA if both are received from the 177 same OSPF router. 179 Implementations which support Local Interface ID signalling via Link 180 Local TE Opaque LSA MAY continue to do so to ensure backward 181 compatibility. If they also support Local Interface ID signalling 182 using LLS as described herein, they MUST signal the same Local 183 Interface ID via both mechanisms. 185 During the rare conditions, when the Local Interface ID changes, a 186 timing interval may exist, where the received values of the Local 187 Interface ID advertised through LLS and Link Local TE Opaque LSA may 188 differ. Such situation is temporary and received values via both 189 mechanisms should become equal as soon as the next Hello and/or Link 190 Local TE Opaque LSA is re-generated by the originator. 192 4. IANA Considerations 194 This specification allocates a single code point from the "Open 195 Shortest Path First (OSPF) Link Local Signalling (LLS) - Type/Length/ 196 Value Identifiers (TLV)" registry. 198 Following value is allocated: 200 o TBD - Local Interface Identifier TLV 202 5. Security Considerations 204 The security considerations for "OSPF Link-Local Signaling" [RFC5613] 205 also apply to the Local Interface Identifier TLV described herein. 206 The current usage of a neighbor's Local Interface Identifier is to 207 disambiguate parallel links between OSPF routers. Hence, 208 modification of the advertised Local Interface Identifier TLV may 209 result in the wrong neighbor interface identifier being advertised in 210 the OSPFv2 Extended Link LSA [RFC7684] and could prevent the link 211 from being used. If authentication is being used in the OSPF routing 212 domain [RFC5709], then the Cryptographic Authentication TLV [RFC5613] 213 SHOULD also be used to protect that contents of the Link-Local 214 Signaling (LLS) block. 216 Receiving a malformed LLS Interface Identifier TLV MUST NOT result in 217 a hard router or OSPF process failure. The reception of malformed 218 LLS TLVs or Sub-TLVs SHOULD be logged but such logging MUST be rate- 219 limited to prevent Denial-of-Service (DoS) attacks. 221 The interface ID is assigned by the advertising OSPF router as a 222 locally unique identifier and need not be unique in any broader 223 context; it is not expected to contain any information about the 224 device owner or traffic transiting the device, so there are no 225 privacy oncerns associated with its advertisement. 227 6. Acknowledgments 229 Thanks to Tony Przygienda for his extensive review and useful 230 comments. 232 7. References 234 7.1. Normative References 236 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 237 Requirement Levels", BCP 14, RFC 2119, 238 DOI 10.17487/RFC2119, March 1997, 239 . 241 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 242 DOI 10.17487/RFC2328, April 1998, 243 . 245 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 246 (TE) Extensions to OSPF Version 2", RFC 3630, 247 DOI 10.17487/RFC3630, September 2003, 248 . 250 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 251 Support of Generalized Multi-Protocol Label Switching 252 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 253 . 255 [RFC5613] Zinin, A., Roy, A., Nguyen, L., Friedman, B., and D. 256 Yeung, "OSPF Link-Local Signaling", RFC 5613, 257 DOI 10.17487/RFC5613, August 2009, 258 . 260 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 261 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 262 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 263 2015, . 265 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 266 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 267 May 2017, . 269 7.2. Informative References 271 [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group 272 MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, 273 . 275 [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., 276 Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic 277 Authentication", RFC 5709, DOI 10.17487/RFC5709, October 278 2009, . 280 Authors' Addresses 281 Peter Psenak (editor) 282 Cisco Systems, Inc. 283 Apollo Business Center 284 Mlynske nivy 43 285 Bratislava 821 09 286 Slovakia 288 Email: ppsenak@cisco.com 290 Ketan Jivan Talaulikar 291 Cisco Systems, Inc. 292 S.No. 154/6, Phase I, Hinjawadi 293 PUNE, MAHARASHTRA 411 057 294 India 296 Email: ketant@cisco.com 298 Wim Henderickx 299 Nokia 300 Copernicuslaan 50 301 Antwerp 2018 302 Belgium 304 Email: wim.henderickx@nokia.com 306 Padma Pillay-Esnault 307 Huawei 308 2330 Central Expressway 309 Santa Clara, CA 95050 310 USA 312 Email: padma@huawei.com