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'HOUSTON' -- Possible downref: Non-RFC (?) normative reference: ref. 'ISO-3166-2' -- Possible downref: Non-RFC (?) normative reference: ref. 'RIS' -- Possible downref: Non-RFC (?) normative reference: ref. 'RIS-ISO-3166' -- Possible downref: Non-RFC (?) normative reference: ref. 'ROUTEVIEWS' ** Obsolete normative reference: RFC 1771 (Obsoleted by RFC 4271) == Outdated reference: A later version (-08) exists of draft-ietf-l2vpn-vpls-bgp-00 -- Possible downref: Non-RFC (?) normative reference: ref. 'WANG' -- Obsolete informational reference (is this intentional?): RFC 2028 (Obsoleted by RFC 9281) -- Obsolete informational reference (is this intentional?): RFC 2434 (Obsoleted by RFC 5226) Summary: 3 errors (**), 0 flaws (~~), 13 warnings (==), 10 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 INTERNET-DRAFT D. Meyer 2 draft-ietf-grow-collection-communities-00.txt 3 Category Best Current Practice 4 Expires: June 2004 December 2003 6 BGP Communities for Data Collection 7 9 Status of this Document 11 This document is an Internet-Draft and is in full conformance with 12 all provisions of Section 10 of RFC2026. 14 Internet-Drafts are working documents of the Internet Engineering 15 Task Force (IETF), its areas, and its working groups. Note that 16 other groups may also distribute working documents as Internet- 17 Drafts. 19 Internet-Drafts are draft documents valid for a maximum of six months 20 and may be updated, replaced, or obsoleted by other documents at any 21 time. It is inappropriate to use Internet-Drafts as reference 22 material or to cite them other than as "work in progress." 24 The list of current Internet-Drafts can be accessed at 25 http://www.ietf.org/ietf/1id-abstracts.txt 27 The list of Internet-Draft Shadow Directories can be accessed at 28 http://www.ietf.org/shadow.html. 30 The key words "MUST"", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 31 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 32 document are to be interpreted as described in RFC 2119 [RFC 2119]. 34 This document is a product of the GROW WG. Comments should be 35 addressed to the authors, or the mailing list at 36 grow@lists.uoregon.edu. 38 Copyright Notice 40 Copyright (C) The Internet Society (2003). All Rights Reserved. 42 Abstract 44 BGP communities (RFC 1997) are used by service providers for many 45 purposes, including tagging of customer, peer, and geographically 46 originated routes. Such tagging is typically used to control the 47 scope of redistribution of routes within a provider's network, and to 48 its peers and customers. With the advent of large scale BGP data 49 collection (and associated research), it has become clear that the 50 information carried in such communities is essential for a deeper 51 understanding of the global routing system. This document defines 52 standard (outbound) communities and their encodings for export to BGP 53 route collectors. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 2. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 2.1. Peers and Peering . . . . . . . . . . . . . . . . . . . . . 5 60 2.2. Customer Routes . . . . . . . . . . . . . . . . . . . . . . 5 61 2.3. Peer Routes . . . . . . . . . . . . . . . . . . . . . . . . 5 62 2.4. Internal Routes . . . . . . . . . . . . . . . . . . . . . . 5 63 2.5. Internal More Specific Routes . . . . . . . . . . . . . . . 5 64 2.6. Special Purpose Routes. . . . . . . . . . . . . . . . . . . 6 65 2.7. Upstream Routes . . . . . . . . . . . . . . . . . . . . . . 6 66 2.8. National Routes . . . . . . . . . . . . . . . . . . . . . . 6 67 2.9. Regional Routes . . . . . . . . . . . . . . . . . . . . . . 6 68 3. RFC 1997 Community Encoding and Values . . . . . . . . . . . . 7 69 3.1. Community Values for BGP Data Collection. . . . . . . . . . 7 70 4. Extended Communities . . . . . . . . . . . . . . . . . . . . . 8 71 5. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 10 72 6. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 10 73 7. Security Considerations. . . . . . . . . . . . . . . . . . . . 11 74 7.1. Total Path Attribute Length . . . . . . . . . . . . . . . . 11 75 8. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 11 76 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 77 9.1. Normative References. . . . . . . . . . . . . . . . . . . . 12 78 9.2. Informative References. . . . . . . . . . . . . . . . . . . 12 79 10. Author's Addresses. . . . . . . . . . . . . . . . . . . . . . 13 80 11. Full Copyright Statement. . . . . . . . . . . . . . . . . . . 13 82 1. Introduction 84 BGP communities [RFC1997] are used by service providers for many 85 purposes, including tagging of customer, peer, and geographically 86 originated routes. Such tagging is typically used to control the 87 scope of redistribution of routes within a providers network, and to 88 it's customers and peers. Communities are also used for a wide 89 variety of other applications, such as allowing customers to set 90 attributes such as LOCAL_PREF [RFC1771] by sending appropriate 91 communities to their service provider. Other applications include 92 signaling various types of VPNs (e.g., VPLS [VPLS]), and carrying 93 link bandwidth for traffic engineering applications [EXTCOMM]. 95 With the advent of large scale BGP data collection [RIS,ROUTEVIEWS] 96 (and associated research), it has become clear that the geographical 97 and topological information, as well as the relationship the provider 98 has to the source of a route (e.g., transit, peer, or customer), 99 carried in such communities is essential for a deeper understanding 100 of the global routing system. This document defines standard 101 communities for export to BGP route collectors. These communities are 102 not (necessarily) intended for internal use by service providers. 103 Rather, they are meant to mirror the information that many service 104 providers carry today, and to be a standardized representation of 105 that information. 107 The remainder of this document is organized as follows. Section 2 108 provides both the definition of terms used as well as the semantics 109 of the communities used for BGP data collection, and section 3 110 defines the corresponding encodings for RFC 1997 [RFC1997] 111 communities. Finally, section 4 defines the encodings for use with 112 extended communities [EXTCOMM]. 114 2. Definitions 116 In this section, we define the terms used and the categories of 117 routes that may be tagged with communities. This tagging is often 118 referred to coloring, and we refer to a route's "color" as its 119 community value. The categories defined here are loosely modeled on 120 those described in [WANG] and [HUSTON]. 122 2.1. Peers and Peering 124 Consider two network service providers, A and B. Service providers A 125 and B are defined to be peers when (i). A and B exchange routes via 126 BGP, and (ii). traffic exchange between A and B is settlement-free. 127 This arrangement is also known as "peering". Peers typically exchange 128 only their respective customer routes (see "Customer Routes" below), 129 and hence exchange only their respective customer traffic. See 130 [HUSTON] for a more in-depth discussion of the business models 131 surrounding peers and peering. 133 2.2. Customer Routes 135 Customer routes are those routes which are heard from a customer via 136 BGP and are propagated to peers and other customers. Note that a 137 customer can be an enterprise or another network service provider. 138 These routes are sometimes called client routes [HUSTON]. 140 2.3. Peer Routes 142 Peer routes are those routes heard from peers via BGP, and not 143 propagated to other peers. In particular, these routes are only 144 propagated to the service provider's customers. 146 2.4. Internal Routes 148 Internal routes are those routes that a service provider originates 149 and passes to its peers and customers. These routes are frequently 150 taken out of the address space allocated to a provider. 152 2.5. Internal More Specific Routes 154 Internal more specific routes are those routes which are frequently 155 used for circuit balancing purposes, IGP route reduction, and also 156 may correspond to customer services which are not visible outside the 157 service provider's network. Internal more specific routes are not 158 exported to any external peer. 160 2.6. Special Purpose Routes 162 Special purpose routes are those routes which do not fall into any of 163 the other classes described here. In those cases in which such routes 164 need to be distinguished, a service provider may color such routes 165 with a unique value. Examples of special purpose routes include 166 anycast routes, and routes for overlay networks. 168 2.7. Upstream Routes 170 Upstream routes are typically learned from upstream service provider 171 as part of a transit service contract executed with the upstream 172 provider. 174 2.8. National Routes 176 These are route sets that are sourced from and/or received within a 177 particular country. 179 2.9. Regional Routes 181 Several global backbones implement regional policy based on their 182 deployed footprint, and on strategic and business imperatives. 183 Service providers often have settlement free interconnections with an 184 AS in one region, and that same AS is a customer in another region. 185 This mandates use of regional routing, including community attributes 186 set by the network in question to allow easy discrimination among 187 regional routes. For example, service providers may treat a route set 188 received from another service provider in Europe differently than the 189 same route set received in North America, as it is common practice to 190 sell transit in one region while peering in the other. 192 3. RFC 1997 Community Encoding and Values 194 In this section we provide standardized RFC 1997 [RFC1997] community 195 values for the categories described above. RFC 1997 communities 196 encoded as BGP Type Code 8, and are treated as 32 bit values ranging 197 from 0x0000000 through 0xFFFFFFF. The values 0x0000000 through 198 0x0000FFFF and 0xFFFF0000 through 0xFFFFFFFF are reserved. 200 The best current practice among service providers is to use the high 201 order two octets to represent the providers AS number, and the low 202 order two octets to represent the classification of the route, as 203 depicted below: 205 0 1 2 3 206 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 1 207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 | | | 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 where 16 bit AS number, and is the encoding of the 212 value. For example, the encoding 0x2A7C029A would represent the AS 213 10876 with value 666. 215 3.1. Community Values for BGP Data Collection 217 In this section we define the RFC 1997 community encoding for the 218 route types described above for use in BGP data collection. It is 219 anticipated that a service provider's internal community values will 220 be converted to these standard values for output to a route 221 collector. 223 This document follows the best current practice of using the basic 224 format :. The values for the route categories are 225 described in the following table: 227 Category Value 228 =============================================================== 229 Customer Routes :64500 230 Peer Routes :64510 231 Internal Routes :64520 232 Internal More Specific Routes :64530 233 Special Purpose Routes :64540 234 Upstream Routes :64550 235 Reserved :64551-65535 236 National and Regional Routes 237 Africa (AF) :0 238 Asia/Australia/Pacific (AP) :1 239 Antarctica (AQ) :2 240 Europe (EU) :3 241 Latin America/Caribbean islands (LAC) :4 242 North America (NA) :5 244 In the above table, the field contains the ISO-3166-2 encoding 245 of the country code [ISO-3166-2,RIS-ISO-3166], which is right- 246 justified (i.e., left zero-padded) in the field. For example, 247 the community 10876:10242 would represent a national route in AS 248 10876 from the Fiji Islands, since the Fiji Islands are in the AP 249 region (Region Code 1) and have ISO-3166-2 numeric country code 242. 250 That is: 252 0 1 2 3 253 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 1 254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 | 0x2A7C | 0x2802 | 256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 258 Finally, note that these categories are not intended to be mutually 259 exclusive, and multiple communities can be attached where 260 appropriate. 262 4. Extended Communities 264 In some cases, the encoding described in section 3.1 may clash with a 265 service provider's existing community assignments. Extended 266 communities [EXTCOMM] provide a convenient mechanism that can be used 267 to avoid such clashes. 269 The Extended Communities Attribute is a transitive optional BGP 270 attribute with the Type Code 16, and consists of a set of extended 271 communities of the following format: 273 0 1 2 3 274 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 1 275 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 276 | Type high | Type low(*) | | 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Value | 278 | | 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 281 For purposes of BGP data collection, we encode the communities 282 described in section 3.1 using the two-octet AS specific extended 283 community type, which has the following format: 285 0 1 2 3 286 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 1 287 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 288 | 0x00 | Sub-Type | Global Administrator | 289 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 290 | Local Administrator | 291 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 293 The two-octet AS specific extended community attribute encodes the 294 service provider's two octet Autonomous System number assigned by 295 IANA in the Global Administrator field, and the Local Administrator 296 field may encode any information. 298 This document assigns Sub-Type 0x05 for BGP data collection, and 299 specifies that the field, as defined in section 3.1, is 300 carried in the low order octets of the Local Administrator field. The 301 two high order octets of the Local Administrator field are reserved, 302 and are set to 0x00 when sending and ignored upon receipt. 304 For example, the extended community encoding for 10876:10242 305 (representing a national route in AS 10876 from the Fiji Islands) 306 would be: 308 0 1 2 3 309 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 1 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 | 0x00 | 0x05 | 0x2A7C | 312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 313 | 0x00 | 0x00 | 0x2802 | 314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 316 5. Intellectual Property 318 The IETF takes no position regarding the validity or scope of any 319 intellectual property or other rights that might be claimed to 320 pertain to the implementation or use of the technology described in 321 this document or the extent to which any license under such rights 322 might or might not be available; neither does it represent that it 323 has made any effort to identify any such rights. Information on the 324 IETF's procedures with respect to rights in standards-track and 325 standards-related documentation can be found in BCP-11 [RFC2028]. 326 Copies of claims of rights made available for publication and any 327 assurances of licenses to be made available, or the result of an 328 attempt made to obtain a general license or permission for the use of 329 such proprietary rights by implementors or users of this 330 specification can be obtained from the IETF Secretariat. 332 The IETF invites any interested party to bring to its attention any 333 copyrights, patents or patent applications, or other proprietary 334 rights which may cover technology that may be required to practice 335 this standard. Please address the information to the IETF Executive 336 Director. 338 6. Acknowledgments 340 Joe Abley, Randy Bush, Sean Donelan, Xenofontas Dimitropoulos, Vijay 341 Gill, John Heasley, Geoff Huston, Steve Huter, Olivier Marce, Ryan 342 McDowell, Rob Rockell, Rob Thomas, and Patrick Verkaik all made many 343 insightful comments on early versions of this draft. Henk Uijterwaal 344 suggested the use of the ISO-3166-2 country codes. 346 7. Security Considerations 348 While this document introduces no additional security considerations 349 into the BGP protocol, the information contained in the communities 350 defined in this document may in some cases reveal network structure 351 that was not previously visible outside the provider's network. As a 352 result, care should be taken when exporting such communities to route 353 collectors. Finally, routes exported to a route collector SHOULD also 354 be tagged with the NO_EXPORT community (0xFFFFFF01). 356 7.1. Total Path Attribute Length 358 The communities described in this document are intended for use on 359 egress to a route collector. Hence an operator may choose to 360 overwrite its internal communities with the values specified in this 361 document when exporting routes to a route collector. However, 362 operators should in general ensure that the behavior of their BGP 363 implementation is well-defined when the addition of an attribute 364 causes a PDU to exceed 4096 octets. For example, since it is common 365 practice to use community attributes to implement policy (among other 366 functionality such as allowing customers to set attributes such as 367 LOCAL_PREF), the behavior of an implementation when the attribute 368 space overflows is crucial. Among other behaviors, an implementation 369 might usurp the intended attribute data or otherwise cause 370 indeterminate failures. These behaviors can result in unanticipated 371 community attribute sets, and hence result in unintended policy 372 implications. 374 8. IANA Considerations 376 This document assigns a new Sub-Type for the AS specific extended 377 community type. In particular, the IANA should assign Sub-type 0x05, 378 using the "First Come First Served" policy defined in RFC 2434 379 [RFC2434], for the Sub-Type defined in Section 4. This corresponds to 380 a Type Field value of 0x0005. 382 9. References 384 9.1. Normative References 386 [EXTCOMM] Sangali, S., D. Tappan and Y. Rekhter, "BGP 387 Extended Communities Attribute", 388 draft-ietf-idr-bgp-ext-communities-06.txt, 389 Work in Progress. 391 [HOUSTON] Huston, G., "Interconnection, Peering, and 392 Settlements", 393 http://www.isoc.org/inet99/proceedings/1e/1e_1.htm 395 [ISO-3166-2] http://www.iso.org/iso/en/prods-services/iso3166ma/index.html 397 [RIS] "Routing Information Service", http://www.ripe.net/ris 399 [RIS-ISO-3166] ftp://ftp.ripe.net/iso3166-countrycodes.txt 401 [ROUTEVIEWS] "The Routeviews Project", http://www.routeviews.org 403 [RFC1771] Rekhter, Y., and T. Li (Editors), "A Border 404 Gateway Protocol (BGP-4)", RFC 1771, March, 405 1995. 407 [RFC1997] Chandra, R. and P. Traina, "BGP Communities 408 Attribute", RFC 1997, August, 1996. 410 [VLPS] Kompella, K., et. al., "Virtual Private LAN 411 Service", draft-ietf-l2vpn-vpls-bgp-00.txt, 412 Work in Progress. 414 [WANG] Wang, F. and L. Gao, "Inferring and Characterizing 415 Internet Routing Policies", ACM SIGCOMM Internet 416 Measurement Conference 2003. 418 9.2. Informative References 420 [RFC2119] Bradner, S., "Key words for use in RFCs to 421 Indicate Requirement Levels", RFC 2119, March, 422 1997. 424 [RFC2026] Bradner, S., "The Internet Standards Process -- 425 Revision 3", RFC 2026/BCP 9, October, 1996. 427 [RFC2028] Hovey, R. and S. Bradner, "The Organizations 428 Involved in the IETF Standards Process", RFC 429 2028/BCP 11, October, 1996. 431 [RFC2434] Narten, T., and H. Alvestrand, "Guidelines for 432 Writing an IANA Considerations Section in RFCs", 433 RFC 2434/BCP 26, October 1998. 435 10. Author's Addresses 437 D. Meyer 439 Email: dmm@1-4-5.net 441 11. Full Copyright Statement 443 Copyright (C) The Internet Society (2003). All Rights Reserved. 445 This document and translations of it may be copied and furnished to 446 others, and derivative works that comment on or otherwise explain it 447 or assist in its implementation may be prepared, copied, published 448 and distributed, in whole or in part, without restriction of any 449 kind, provided that the above copyright notice and this paragraph are 450 included on all such copies and derivative works. However, this 451 document itself may not be modified in any way, such as by removing 452 the copyright notice or references to the Internet Society or other 453 Internet organizations, except as needed for the purpose of 454 developing Internet standards in which case the procedures for 455 copyrights defined in the Internet Standards process must be 456 followed, or as required to translate it into languages other than 457 English. 459 The limited permissions granted above are perpetual and will not be 460 revoked by the Internet Society or its successors or assigns. 462 This document and the information contained herein is provided on an 463 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 464 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 465 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 466 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 467 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.