idnits 2.17.1 draft-ietf-isis-ipv6-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** Looks like you're using RFC 2026 boilerplate. This must be updated to follow RFC 3978/3979, as updated by RFC 4748. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- ** The document seems to lack a 1id_guidelines paragraph about 6 months document validity -- however, there's a paragraph with a matching beginning. Boilerplate error? == No 'Intended status' indicated for this document; assuming Proposed Standard Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** The document seems to lack separate sections for Informative/Normative References. All references will be assumed normative when checking for downward references. ** There is 1 instance of too long lines in the document, the longest one being 3 characters in excess of 72. ** The abstract seems to contain references ([2], [0], [1]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == Line 235 has weird spacing: '...for the purpo...' == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- 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 (1 January 2000) is 8881 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) -- Possible downref: Non-RFC (?) normative reference: ref. '0' -- Possible downref: Non-RFC (?) normative reference: ref. '2' Summary: 6 errors (**), 0 flaws (~~), 4 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Internet Engineering Task Force Christian E. Hopps 2 INTERNET-DRAFT Merit Network 3 Expires June 2000 1 January 2000 5 Routing IPv6 with IS-IS 6 8 Status of this Memo 10 This document is an Internet-Draft and is in full conformance with 11 all provisions of Section 10 of RFC2026. 13 Internet-Drafts are working documents of the Internet Engineering 14 Task Force (IETF), its areas, and its working groups. Note that 15 other groups may also distribute working documents as Internet- 16 Drafts. 18 Internet-Drafts are draft documents valid for a maximum of six months 19 and may be updated, replaced, or obsoleted by other documents at any 20 time. It is inappropriate to use Internet- Drafts as reference 21 material or to cite them other than as "work in progress." 23 The list of current Internet-Drafts can be accessed at 24 http://www.ietf.org/ietf/1id-abstracts.txt 26 The list of Internet-Draft Shadow Directories can be accessed at 27 http://www.ietf.org/shadow.html. 29 Copyright Notice 31 Copyright (C) The Internet Society (2000). All Rights Reserved. 33 Draft Routing IPv6 with IS-IS January 2000 35 Abstract 37 This draft specifies a method for exchanging IPv6 routing information 38 using the IS-IS routing protocol [0]. The method utilizes the same 39 mechanisms described in RFC 1195 [1]. This is accomplished by adding 40 2 new TLVs and defining their use. These new TLVs are patterned from 41 the ones described in "IS-IS extensions for Traffic Engineering" [2]. 43 Just as in RFC 1195 [1] with IPv4 and OSI, this method allows one to 44 route both IPv4 and IPv6 using a single intra-domain routing 45 protocol. 47 1. Terms 49 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 50 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 51 document are to be interpreted as described in RFC 2119. 53 2. Overview 55 IS-IS is an extendible intra-domain routing protocol. Each router in 56 the routing domain issues an LSP that contains information pertaining 57 to that router. The LSP contains typed variable length data often 58 referred to as TLVs (type-length-values). We extend the protocol 59 with 2 new TLVs to carry information required to perform IPv6 60 routing. 62 In [1] a method is described to route both OSI and IPv4. We utilize 63 this same method with some minor changes to allow for IPv6. To do so 64 we must define 2 new TLVs, namely "IPv6 Reachability" and "IPv6 65 Interface Address" and a new IPv6 protocol identifier. In our new 66 TLVs we utilize the extended metrics and up/down semantics of [2]. 68 3. IPv6 Reachability TLV 70 The "IPv6 Reachability" TLV is TLV type TBD. 72 [1] defines 2 Reachability TLVs, "IP Internal Reachability 73 Information" and "IP External Reachability Information". We provide 74 the equivalent IPv6 data with the "IPv6 Reachability" TLV and an 75 "external" bit. 77 Draft Routing IPv6 with IS-IS January 2000 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 4 octets of metric information 88 1 octet of control information 89 1 bit of up/down information 90 1 bit indicating external origination 91 (e.g., from another routing protocol) 92 1 bit indicating the existence of sub-TLVs 93 5 reserved bits which must be zero and ignored 94 1 octet of prefix length 95 0-16 octets of prefix 96 0-249 optional octets of sub-TLVs, if present consisting of 97 1 octet of length of sub-TLVs 98 0-248 octets of sub-TLVs 100 This structure may appear any number of times (including none) within 101 the TLV. 103 As is described in [2], "the up/down bit is set to 0 when a prefix is 104 first injected into IS-IS. If a prefix is redistributed from a 105 higher level to a lower level (e.g., level two to level one), the bit 106 shall be set to 1 to indicate that the prefix has travelled down the 107 hierarchy. If a prefix is redistributed from an area to another area 108 at the same level then the up/down bit shall be set to 1." 110 If the prefix was distributed into IS-IS from another routing 111 protocol the external bit shall be set to 1. This information is 112 useful when distributing prefixes from IS-IS to other protocols. 114 If the sub-TLV bit is set to 0 then the optional octets of sub-TLVs 115 are not present. Otherwise the bit is 1 and the octet following the 116 prefix will contain the length of the sub-TLV portion of the 117 structure. 119 The prefix is "packed" in the data structure. That is, only the 120 required number of octets of prefix are present. This number can be 121 computed from the prefix length octet as follows: 123 prefix octets = integer of ((prefix length + 7) / 8) 125 Draft Routing IPv6 with IS-IS January 2000 127 Just as in [2], if a prefix is advertised with a metric larger than 128 MAX_V6_PATH_METRIC (0xFE000000), this prefix should not be considered 129 during the normal SPF computation. This will allow advertisement of 130 a prefix for other purposes than building the normal IPv6 routing 131 table. 133 4. IPv6 Interface Address TLV 135 The "IPv6 Interface Address" TLV is TLV type TBD. 137 This TLV maps directly to [1]'s "IP Interface Address" TLV. We 138 necessarily modify the contents to be 0-15 16 octet IPv6 interface 139 addresses instead of 0-63 4 octet IPv4 interface address. 141 We further restrict the semantics of this TLV depending on where it 142 is advertised. For Hello PDUs the "Interfaces Address" TLV must 143 contain only the link-local IPv6 addresses assigned to the interface 144 which is sending the Hello. For LSPs the "Interfaces Address" TLVs 145 must contain only the non-link-local IPv6 addresses assigned to the 146 IS. 148 5. IPv6 NLPID 150 The value of the IPv6 NLPID is TBD. 152 As with [1] and IPv4, if the IS supports IPv6 routing using IS-IS, it 153 must advertise this in the "NLPID" TLV by adding the IPv6 NLPID. 155 6. Operation 157 We utilize the same changes to [1] as made in [2] for the processing 158 of prefix information. These changes are both related to the SPF 159 calculation. 161 Since the metric space has been extended we need to redefine the 162 MAX_PATH_METRIC (1023) from the original specification in [1]. This 163 new value MAX_V6_PATH_METRIC is the same as in [2] (0xFE000000). If 164 during the SPF a path metric would exceed MAX_V6_PATH_METRIC it shall 165 be considered to be MAX_V6_PATH_METRIC. 167 The order of preference between paths for a given prefix must be 168 modified to consider the up/down bit. The new order of preference is 170 Draft Routing IPv6 with IS-IS January 2000 172 as follows (from best to worst). 174 1. Level 1 up prefix 175 2. Level 2 up prefix 176 3. Level 2 down prefix 177 4. Level 1 down prefix 179 If multiple paths have the same best preference then selection occurs 180 based on metric. Any remaining multiple paths should be considered 181 for equal-cost multi-path routing if the router supports this, otherwise 182 the router can select any one of the multiple paths. 184 7. Encapsulation of IS-IS PDUs 186 There is no method currently defined for encapsulation of IS-IS PDUs 187 in IPv6 packets. Based on further study, future versions of this 188 draft may specify an optional method for encapsulating IS-IS PDUs in 189 IPv6 packets. 191 8. Implementations 193 An implementation of this draft has been completed in GateD. 195 9. Security Considerations 197 This document raises no new security considerations. 199 10. References 201 [0] "Intermediate System to Intermediate System Intra-Domain Routeing 202 Exchange Protocol for use in Conjunction with the Protocol for 203 Providing the Connectionless-mode Network Service (ISO 8473)", ISO 204 10589, 1992. 206 [1] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual 207 Environments", RFC 1195, December 1990. 209 [2] Smit, H., and T. Li, "IS-IS extensions for Traffic Engineering", 210 Work in Progress, May 1999. 212 Draft Routing IPv6 with IS-IS January 2000 214 11. Author's Address 216 Christian E. Hopps 217 Merit Network 218 4251 Plymouth Road, Suite C. 219 Ann Arbor, MI 48105 220 Phone: +1 734 936 0291 221 Email: chopps@merit.edu 223 12. Full Copyright Statement 225 Copyright (C) The Internet Society 2000. All Rights Reserved. 227 This document and translations of it may be copied and furnished to 228 others, and derivative works that comment on or otherwise explain it 229 or assist in its implementation may be prepared, copied, published 230 and distributed, in whole or in part, without restriction of any 231 kind, provided that the above copyright notice and this paragraph are 232 included on all such copies and derivative works. However, this 233 document itself may not be modified in any way, such as by removing 234 the copyright notice or references to the Internet Society or other 235 Internet organizations, except as needed for the purpose of 236 developing Internet standards in which case the procedures for 237 copyrights defined in the Internet Standards process must be 238 followed, or as required to translate it into languages other than 239 English. 241 The limited permissions granted above are perpetual and will not be 242 revoked by the Internet Society or its successors or assigns. 244 This document and the information contained herein is provided on an 245 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 246 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 247 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 248 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 249 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.