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Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust Copyright Line does not match the current year == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: Just as in [RFC2784], if a prefix is advertised with a metric larger than MAX_V6_PATH_METRIC (0xFE000000), this prefix MUST not be considered during the normal SPF computation. This will allow advertisement of a prefix for purposes other than building the normal IPv6 routing table. -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (October 4, 2007) is 6050 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) == Unused Reference: 'RFC3787' is defined on line 265, but no explicit reference was found in the text -- Possible downref: Non-RFC (?) normative reference: ref. 'ISO10589' ** Obsolete normative reference: RFC 2434 (Obsoleted by RFC 5226) ** Obsolete normative reference: RFC 3567 (Obsoleted by RFC 5304) Summary: 3 errors (**), 0 flaws (~~), 3 warnings (==), 8 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IS-IS for IP Internets C. Hopps 3 Internet-Draft Cisco Systems 4 Intended status: Standards Track October 4, 2007 5 Expires: April 6, 2008 7 Routing IPv6 with IS-IS 8 draft-ietf-isis-ipv6-07 10 Status of this Memo 12 By submitting this Internet-Draft, each author represents that any 13 applicable patent or other IPR claims of which he or she is aware 14 have been or will be disclosed, and any of which he or she becomes 15 aware will be disclosed, in accordance with Section 6 of BCP 79. 17 Internet-Drafts are working documents of the Internet Engineering 18 Task Force (IETF), its areas, and its working groups. Note that 19 other groups may also distribute working documents as Internet- 20 Drafts. 22 Internet-Drafts are draft documents valid for a maximum of six months 23 and may be updated, replaced, or obsoleted by other documents at any 24 time. It is inappropriate to use Internet-Drafts as reference 25 material or to cite them other than as "work in progress." 27 The list of current Internet-Drafts can be accessed at 28 http://www.ietf.org/ietf/1id-abstracts.txt. 30 The list of Internet-Draft Shadow Directories can be accessed at 31 http://www.ietf.org/shadow.html. 33 This Internet-Draft will expire on April 6, 2008. 35 Copyright Notice 37 Copyright (C) The IETF Trust (2007). 39 Abstract 41 This draft specifies a method for exchanging IPv6 routing information 42 using the IS-IS routing protocol. The described method utilizes 2 43 new TLVs, a reachability TLV and an interface address TLV to 44 distribute the necessary IPv6 information throughout a routing 45 domain. Using this method one can route IPv6 along with IPv4 and OSI 46 using a single intra-domain routing protocol. 48 Requirements Language 50 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 51 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 52 document are to be interpreted as described in RFC 2119 [RFC2119]. 54 1. Overview 56 IS-IS is an extendible intra-domain routing protocol. Each router in 57 the routing domain issues an LSP that contains information pertaining 58 to that router. The LSP contains typed variable length data often 59 referred to as TLVs (type-length-values). We extend the protocol 60 with 2 new TLVs to carry information required to perform IPv6 61 routing. 63 In [RFC1195] a method is described to route both OSI and IPv4. We 64 utilize this same method with some minor changes to allow for IPv6. 65 To do so we must define 2 new TLVs, namely "IPv6 Reachability" and 66 "IPv6 Interface Address" and a new IPv6 protocol identifier. In our 67 new TLVs we utilize the extended metrics and up/down semantics of 68 [RFC2784]. 70 2. IPv6 Reachability TLV 72 The "IPv6 Reachability" TLV is TLV type 236 (0xEC). 74 [RFC1195] defines 2 Reachability TLVs, "IP Internal Reachability 75 Information" and "IP External Reachability Information". We provide 76 the equivalent IPv6 data with the "IPv6 Reachability" TLV and an 77 "external" bit. 79 The "IPv6 Reachability" TLV describes network reachability through 80 the specification of a routing prefix, metric information, a bit to 81 indicate if the prefix is being advertised down from a higher level, 82 a bit to indicate if the prefix is being distributed from another 83 routing protocol and OPTIONALLY the existence of Sub-TLVs to allow 84 for later extension. This data is represented by the following 85 structure: 87 0 1 2 3 88 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 89 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 90 | Type = 236 | Length | Metric .. | 91 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 92 | .. Metric |U|X|S| Reserve | Prefix Len | 93 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 94 | Prefix ... 95 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 96 |Sub-TLV Len(*) | Sub-TLVs(*) ... 97 * - if present 99 U - up/down bit 100 X - external original bit 101 S - subtlv present bit 103 The above IPv6 Reachability TLV MAY appear any number of times 104 (including none) within an LSP. Link-local prefixes MUST NOT be 105 advertised using this TLV. 107 As is described in [RFC2784], "the up/down bit is set to 0 when a 108 prefix is first injected into IS-IS. If a prefix is redistributed 109 from a higher level to a lower level (e.g., level two to level one), 110 the bit SHALL be set to 1 to indicate that the prefix has travelled 111 down the hierarchy. If a prefix is redistributed from an area to 112 another area at the same level then the up/down bit SHALL be set to 113 1." 115 If the prefix was distributed into IS-IS from another routing 116 protocol the external bit SHALL be set to 1. This information is 117 useful when distributing prefixes from IS-IS to other protocols. 119 If the Sub-TLV bit is set to 0 then the octets of Sub-TLVs are not 120 present. Otherwise the bit is 1 and the octet following the prefix 121 will contain the length of the Sub-TLV portion of the structure. 123 The prefix is "packed" in the data structure. That is, only the 124 required number of octets of prefix are present. This number can be 125 computed from the prefix length octet as follows: 127 prefix octets = integer of ((prefix length + 7) / 8) 129 Just as in [RFC2784], if a prefix is advertised with a metric larger 130 than MAX_V6_PATH_METRIC (0xFE000000), this prefix MUST not be 131 considered during the normal SPF computation. This will allow 132 advertisement of a prefix for purposes other than building the normal 133 IPv6 routing table. 135 If Sub-TLVs are present they have the same form as normal TLVs as 136 shown below. 138 0 1 2 3 139 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 1 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 | Type | Length | Value(*) .. 142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 143 * - if present 145 Length indicates how many octets of value are present and can be 0. 147 3. IPv6 Interface Address TLV 149 The "IPv6 Interface Address" TLV is TLV type 232 (0xE8). 151 TLV 232 maps directly to "IP Interface Address" TLV in [RFC1195] . 152 We necessarily modify the contents to be 0-15 16 octet IPv6 interface 153 addresses instead of 0-63 4 octet IPv4 interface address. 155 0 1 2 3 156 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 1 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | Type = 232 | Length | Interface Address 1(*) .. | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | .. Interface Address 1(*) .. | 161 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 | .. Interface Address 1(*) .. | 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 | .. Interface Address 1(*) .. | 165 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 166 | Interface Address 1(*) .. | Interface Address 2(*) .. 167 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 168 * - if present 170 We further restrict the semantics of this TLV depending on where it 171 is advertised. For Hello PDUs the "Interfaces Address" TLV MUST 172 contain only the link-local IPv6 addresses assigned to the interface 173 which is sending the Hello. For LSPs the "Interfaces Address" TLVs 174 MUST contain only the non-link-local IPv6 addresses assigned to the 175 IS. 177 4. IPv6 NLPID 179 The value of the IPv6 NLPID is 142 (0x8E). 181 As with [RFC1195] and IPv4, if the IS supports IPv6 routing using 182 IS-IS, it MUST advertise this in the "NLPID" TLV by adding the IPv6 183 NLPID. 185 5. Operation 187 We utilize the same changes to [RFC1195] as made in [RFC2784] for the 188 processing of prefix information. These changes are both related to 189 the SPF calculation. 191 Since the metric space has been extended we need to redefine the 192 MAX_PATH_METRIC (1023) from the original specification in [RFC1195]. 193 This new value MAX_V6_PATH_METRIC is the same as in [RFC2784] 194 (0xFE000000). If during the SPF a path metric would exceed 195 MAX_V6_PATH_METRIC it SHALL be considered to be MAX_V6_PATH_METRIC. 197 The order of preference between paths for a given prefix MUST be 198 modified to consider the up/down bit. The new order of preference is 199 as follows (from best to worst). 201 1. Level 1 up prefix 203 2. Level 2 up prefix 205 3. Level 2 down prefix 207 4. Level 2 down prefix 209 If multiple paths have the same best preference then selection occurs 210 based on metric. Any remaining multiple paths SHOULD be considered 211 for equal-cost multi-path routing if the router supports this, 212 otherwise the router can select any one of the multiple paths. 214 6. IANA Considerations 216 IANA is requested to update the IS-IS codepoint registry 217 (http://www.iana.org/assignments/isis-tlv-codepoints) so that TLV 218 codes 232 and 236 refer to this document's RFC number. 220 IANA is additionally requested to create the following new code-point 221 registry for Sub-TLVs of TLV 236. The range of values for Type is 222 0-255. Allocations within the registry require documentation of the 223 use and approval by the Designated Expert assigned by the IESG 224 [RFC2434]. All code-points are currently unassigned. 226 Note to RFC Editor: this section may be removed on publication as an 227 RFC. 229 7. Security Considerations 231 This document raises no new security considerations. Security 232 considerations for the IS-IS protocol are covered in [ISO10589] and 233 in [RFC3567]. 235 8. References 237 8.1. Normative References 239 [ISO10589] 240 "Intermediate System to Intermediate System Intra-Domain 241 Routeing Exchange Protocol for use in Conjunction with the 242 Protocol for Providing the Connectionless-mode Network 243 Service (ISO 8473)", 1992. 245 [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and 246 dual environments", RFC 1195, December 1990. 248 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 249 Requirement Levels", BCP 14, RFC 2119, March 1997. 251 [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 252 IANA Considerations Section in RFCs", BCP 26, RFC 2434, 253 October 1998. 255 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 256 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 257 March 2000. 259 [RFC3567] Li, T. and R. Atkinson, "Intermediate System to 260 Intermediate System (IS-IS) Cryptographic Authentication", 261 RFC 3567, July 2003. 263 8.2. Informative References 265 [RFC3787] Parker, J., "Recommendations for Interoperable IP Networks 266 using Intermediate System to Intermediate System (IS-IS)", 267 RFC 3787, May 2004. 269 Author's Address 271 Christian E. Hopps 272 Cisco Systems 273 170 W. Tasman Dr. 274 San Jose, California 95134 275 USA 277 Email: chopps@cisco.com 279 Full Copyright Statement 281 Copyright (C) The IETF Trust (2007). 283 This document is subject to the rights, licenses and restrictions 284 contained in BCP 78, and except as set forth therein, the authors 285 retain all their rights. 287 This document and the information contained herein are provided on an 288 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 289 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 290 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 291 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 292 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 293 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 295 Intellectual Property 297 The IETF takes no position regarding the validity or scope of any 298 Intellectual Property Rights or other rights that might be claimed to 299 pertain to the implementation or use of the technology described in 300 this document or the extent to which any license under such rights 301 might or might not be available; nor does it represent that it has 302 made any independent effort to identify any such rights. Information 303 on the procedures with respect to rights in RFC documents can be 304 found in BCP 78 and BCP 79. 306 Copies of IPR disclosures made to the IETF Secretariat and any 307 assurances of licenses to be made available, or the result of an 308 attempt made to obtain a general license or permission for the use of 309 such proprietary rights by implementers or users of this 310 specification can be obtained from the IETF on-line IPR repository at 311 http://www.ietf.org/ipr. 313 The IETF invites any interested party to bring to its attention any 314 copyrights, patents or patent applications, or other proprietary 315 rights that may cover technology that may be required to implement 316 this standard. Please address the information to the IETF at 317 ietf-ipr@ietf.org. 319 Acknowledgment 321 Funding for the RFC Editor function is provided by the IETF 322 Administrative Support Activity (IASA).