idnits 2.17.1 draft-ietf-ipngwg-scoped-routing-02.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: ---------------------------------------------------------------------------- ** Missing document type: Expected "INTERNET-DRAFT" in the upper left hand corner of the first page ** 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 == The page length should not exceed 58 lines per page, but there was 6 longer pages, the longest (page 2) being 69 lines 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 are 84 instances of too long lines in the document, the longest one being 8 characters in excess of 72. ** The abstract seems to contain references ([RFC2119]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. Miscellaneous warnings: ---------------------------------------------------------------------------- == 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 (May 2000) is 8748 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: 7 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 IPNGWG Working Group B. Haberman 2 Internet Draft Nortel Networks 3 draft-ietf-ipngwg-scoped-routing-02.txt 4 November 1999 5 Expires May 2000 7 Routing of Scoped Addresses 8 in the Internet Protocol Version 6 (IPv6) 10 Status of this Memo 12 This document is an Internet-Draft and is in full conformance with all 13 provisions of Section 10 of RFC2026. 15 Internet-Drafts are working documents of the Internet Engineering Task 16 Force (IETF), its areas, and its working groups. Note that other groups 17 may also distribute working documents as Internet-Drafts. Internet- 18 Drafts are draft documents valid for a maximum of six months and may be 19 updated, replaced, or obsoleted by other documents at any time. It is 20 inappropriate to use Internet- Drafts as reference material or to cite 21 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 Abstract 31 This document outlines a mechanism for generating forwarding tables 32 that include scoped IPv6 addresses. It defines a set of rules for 33 routers to implement in order to forward packets addressed to scoped 34 unicast or multicast addresses regardless of the routing protocol. 35 These rules apply to all scoped addresses. 37 1. 38 Introduction 40 This document defines a set of rules for the generation of forwarding 41 table entries for scoped addresses. These rules will describe the 42 handling of scoped addresses for both single site and site boundary 43 routers. These rules apply to all routing protocols that support IPv6 44 addresses. 46 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 47 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 48 document are to be interpreted as described in [RFC 2119]. 50 2. 51 Assumptions and Definitions 53 This document makes several assumptions concerning sites: 55 - Links belong to at most one site 56 - Interfaces belong to the site of the attached link, if any 58 Haberman 1 59 - Nodes are a part of all sites which their interfaces belong to, 60 and no other sites 61 - Site boundaries are identical for unicast and multicast traffic 62 - A single interface can be in at most one site 63 - Each interface participating in a site has a site identifier 64 - In the absence of explicit configuration, all site identifiers on 65 a node default to the same value 67 A single site router is defined as a router configured with the same 68 site identifier on all interfaces. A site boundary router is defined 69 as a router that has at least 2 distinct site identifiers. 71 * * 72 * * 73 * Site ID = X * 74 * * 75 +-*---|-------|---*-+ 76 | * i/f 1 i/f 2 * | 77 | *************** | 78 | | 79 | | 80 | Router | 81 ******************* ******************* 82 | * * | 83 Site ID = Y -i/f 3 * * i/f 4- Site ID = Default 84 | * * | 85 ******************* ******************* 86 +-------------------+ 88 Figure 1: Multi-Sited Router 90 3. 91 Single Site Routing 93 In a single site router, a routing protocol can advertise and route all 94 addresses and prefixes, except the link-local prefixes, on all 95 interfaces. This configuration does not require any special handling 96 for site local addresses. The reception and transmission of site local 97 addresses is handled in the same manner as globally scoped addresses. 98 This applies to both unicast and multicast routing protocols. 100 4. 101 Site Boundary Unicast Routing 103 With respect to site boundaries, routers must consider which interfaces 104 a packet can be transmitted on as well as control the propagation of 105 routing information specific to the site. This includes controlling 106 which prefixes can be advertised on an interface. 108 4.1 Routing Protocols 110 When a routing protocol determines that it is a site boundary router, 111 it must perform additional work in order to protect inter site 112 integrity and still maintain intra site connectivity. 114 Haberman 2 115 In order to maintain connectivity, the routing protocol must be able to 116 create forwarding information for the global prefixes as well as for 117 all of the site prefixes for each of its attached sites. The most 118 straightforward way of doing this is to create up to (n+1) forwarding 119 tables; one for the global prefixes, if any, and one for each of the 120 (n) sites. 122 To protect inter site integrity; routers must be selective in the 123 forwarding information that is shared with neighboring routers. 124 Routing protocols routinely transmit their routing information to its 125 neighboring routers. When a router is transmitting this routing 126 information, it must not include any information about sites other than 127 the site defined on the interface used to reach a neighbor. 129 As an example, the router in Figure 1 must advertise routing 130 information on four interfaces. The information advertised is as 131 follows: 133 - Interface 1 134 - All global prefixes 135 - All site prefixes learned from Interfaces 1 and 2 136 - Interface 2 137 - All global prefixes 138 - All site prefixes learned from Interfaces 1 and 2 139 - Interface 3 140 - All global prefixes 141 - All site prefixes learned from Interface 3 142 - Interface 4 143 - All global prefixes 144 - No site prefixes 146 By imposing advertisement rules, site integrity is maintained by 147 keeping all site routing information contained within the site. 149 4.2 Packet Forwarding 151 In addition to the extra cost of generating additional forwarding 152 information for each site, site boundary routers must also do some 153 additional checking when forwarding packets that contain site local 154 addresses. 156 If a packet being forwarded contains a site local destination address, 157 regardless of the scope of the source address, the router must perform 158 the following: 160 - Lookup incoming interface's site identifier 161 - Perform route lookup for destination address in arrival 162 interface's site scoped routing table 164 If a packet being forwarded contains a site local source address and a 165 global scoped destination address, the following must be performed: 167 - Lookup outgoing interface's site identifier 168 - Compare inbound and outbound interfaces' site identifiers 170 If the site identifiers match, the packet can be forwarded. If they do 171 not match, an ICMPv6 destination unreachable message must be sent to 173 Haberman 3 174 the sender with a code value, code = 2 (beyond scope of source 175 address). 177 5. 178 Scoped Multicast Routing 180 With IPv6 multicast, there are multiple scopes supported. Multicast 181 routers must be able to control the propagation of scoped packets based 182 on administratively configured boundaries. 184 5.1 Routing Protocols 186 Multicast routing protocols must follow the same rules as the unicast 187 protocols. They will be required to maintain information about global 188 prefixes as well as information about all scope boundaries that exist 189 on the router. 191 Multicast protocols that rely on underlying unicast protocols for route 192 exchange (i.e. PIM, MOSPF) will not suffer as much of a performance 193 impact since the unicast protocol will handle the forwarding table 194 generation. They must be able to handle the additional scope 195 boundaries used in multicast addresses. 197 Multicast protocols that generate and maintain their own routing tables 198 will have to perform the additional route calculations for scope 199 boundaries. All multicast protocols will be forced to handle fourteen 200 additional scooping identifiers above the site identifiers supported in 201 IPv6 unicast addresses. 203 5.2 Packet Forwarding 205 The following combinations describe the forwarding rules for multicast: 207 - Global multicast destination / Global unicast source 208 - Global multicast destination / Site local unicast source 209 - Scoped multicast destination / Global unicast source 210 - Scoped multicast destination / Site local unicast source 212 The first combination requires no special processing over what is 213 currently in place for global IPv6 multicast. The remaining 214 combinations should result in the router performing the same 215 identifiers check as outlined for the site local unicast addresses. 216 Since IPv6 multicast supports fifteen unique multicast scopes, it is 217 assumed that scopes 0x1 through 0x4 are strictly less than the unicast 218 site scope, scope 0x5 (site) is equal to the unicast site scope, scopes 219 0x6 through 0xd are strictly greater than the unicast site scope and 220 strictly less than the unicast global scope, and scope 0xe is equal to 221 the unicast global scope. 223 6. 224 Protocol Impact 226 The performance impact on routing protocols is obvious. Routers 227 implementing scoped address support will be forced to perform an 228 additional check in the main forwarding path to determine if the source 229 address is a site-local address. This will add overhead to the 230 processing of every packet flowing through the router. In addition, 232 Haberman 4 233 there will be some storage overhead for the scope identifiers. If 234 scoped addresses are going to be realized, this performance impact may 235 be acceptable. 237 7. 238 Security Considerations 240 This document specifies a set of guidelines that allow routers to 241 prevent site-specific information from leaking out of each site. If 242 site boundary routers allow site routing information to be forwarded 243 outside of the site, the integrity of the site could be compromised. 245 8. 246 References 248 [RFC 2119] S. Bradner, "Key words for use in RFCs to Indicate 249 Requirement Levels", RFC 2119, BCP14, March 1999. 251 Acknowledgements 253 The author would like to thank Thomas Narten, Steve Deering, Erik 254 Nordmark, and Matt Crawford for their comments and reviews of this 255 document. 257 Haberman 5 258 Author's Address 260 Brian Haberman 261 Nortel Networks 262 4309 Emperor Blvd. 263 Suite 200 264 Durham, NC 27703 265 1-919-992-4439 266 Email : haberman@nortelnetworks.com 268 Haberman 6