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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 'ROUTEVIEWS' ** Obsolete normative reference: RFC 1771 (Obsoleted by RFC 4271) == Outdated reference: A later version (-08) exists of draft-ietf-l2vpn-vpls-bgp-00 -- Possible downref: Non-RFC (?)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-meyer-collection-communities-00.txt 3 Category Best Current Practice 4 Expires: May 2004 November 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 an individual submission. Comments are solicited and 35 should be addressed to the author(s). 37 Copyright Notice 39 Copyright (C) The Internet Society (2003). All Rights Reserved. 41 Abstract 43 BGP communities (RFC 1997) are used by service providers for many 44 purposes, including tagging of customer, peer, and geographically 45 originated routes. Such tagging is typically used to control the 46 scope of redistribution of routes within a provider's network, and to 47 its peers and customers. With the advent of large scale BGP data 48 collection (and associated research), it has become clear that the 49 information carried in such communities is essential for a deeper 50 understanding of the global routing system. This document defines 51 standard (outbound) communities and their encodings for export to BGP 52 route collectors. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 57 2. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 2.1. Peers and Peering . . . . . . . . . . . . . . . . . . . . . 5 59 2.2. Customer Routes . . . . . . . . . . . . . . . . . . . . . . 5 60 2.3. Peer Routes . . . . . . . . . . . . . . . . . . . . . . . . 5 61 2.4. Internal Routes . . . . . . . . . . . . . . . . . . . . . . 5 62 2.5. Internal More Specific Routes . . . . . . . . . . . . . . . 5 63 2.6. Special Purpose Routes. . . . . . . . . . . . . . . . . . . 6 64 2.7. Upstream Routes . . . . . . . . . . . . . . . . . . . . . . 6 65 2.8. National Routes . . . . . . . . . . . . . . . . . . . . . . 6 66 2.9. Regional Routes . . . . . . . . . . . . . . . . . . . . . . 6 67 3. RFC 1997 Community Encoding and Values . . . . . . . . . . . . 7 68 3.1. Community Values for BGP Data Collection. . . . . . . . . . 7 69 4. Extended Communities . . . . . . . . . . . . . . . . . . . . . 8 70 5. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 10 71 6. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 10 72 7. Security Considerations. . . . . . . . . . . . . . . . . . . . 11 73 7.1. Total Path Attribute Length . . . . . . . . . . . . . . . . 11 74 8. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 11 75 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 76 9.1. Normative References. . . . . . . . . . . . . . . . . . . . 12 77 9.2. Informative References. . . . . . . . . . . . . . . . . . . 12 78 10. Author's Addresses. . . . . . . . . . . . . . . . . . . . . . 13 79 11. Full Copyright Statement. . . . . . . . . . . . . . . . . . . 13 81 1. Introduction 83 BGP communities [RFC1997] are used by service providers for many 84 purposes, including tagging of customer, peer, and geographically 85 originated routes. Such tagging is typically used to control the 86 scope of redistribution of routes within a providers network, and to 87 it's customers and peers. Communities are also used for a wide 88 variety of other applications, such as allowing customers to set 89 attributes such as LOCAL_PREF [RFC1771] by sending appropriate 90 communities to their service provider. Other applications include 91 signaling various types of VPNs (e.g., VPLS [VPLS]), and carrying 92 link bandwidth for traffic engineering applications [EXTCOMM]. 94 With the advent of large scale BGP data collection [RIS,ROUTEVIEWS] 95 (and associated research), it has become clear that the geographical 96 and topological information, as well as the relationship the provider 97 has to the source of a route (e.g., transit, peer, or customer), 98 carried in such communities is essential for a deeper understanding 99 of the global routing system. This document defines standard 100 communities for export to BGP route collectors. These communities are 101 not (necessarily) intended for internal use by service providers. 102 Rather, they are meant to mirror the information that many service 103 providers carry today, and to be a standardized representation of 104 that information. 106 The remainder of this document is organized as follows. Section 2 107 provides both the definition of terms used as well as the semantics 108 of the communities used for BGP data collection, and section 3 109 defines the corresponding encodings for RFC 1997 [RFC1997] 110 communities. Finally, section 4 defines the encodings for use with 111 extended communities [EXTCOMM]. 113 2. Definitions 115 In this section, we define the terms used and the categories of 116 routes that may be tagged with communities. This tagging is often 117 referred to coloring, and we refer to a route's "color" as its 118 community value. The categories defined here are loosely modeled on 119 those described in [WANG] and [HUSTON]. 121 2.1. Peers and Peering 123 Consider two network service providers, A and B. Service providers A 124 and B are defined to be peers when (i). A and B exchange routes via 125 BGP, and (ii). traffic exchange between A and B is settlement-free. 126 This arrangement is also known as "peering". Peers typically exchange 127 only their respective customer routes (see "Customer Routes" below), 128 and hence exchange only their respective customer traffic. See 129 [HUSTON] for a more in-depth discussion of the business models 130 surrounding peers and peering. 132 2.2. Customer Routes 134 Customer routes are those routes which are heard from a customer via 135 BGP and are propagated to peers and other customers. Note that a 136 customer can be an enterprise or another network service provider. 137 These routes are sometimes called client routes [HUSTON]. 139 2.3. Peer Routes 141 Peer routes are those routes heard from peers via BGP, and not 142 propagated to other peers. In particular, these routes are only 143 propagated to the service provider's customers. 145 2.4. Internal Routes 147 Internal routes are those routes that a service provider originates 148 and passes to its peers and customers. These routes are frequently 149 taken out of the address space allocated to a provider. 151 2.5. Internal More Specific Routes 153 Internal more specific routes are those routes which are frequently 154 used for circuit balancing purposes, IGP route reduction, and also 155 may correspond to customer services which are not visible outside the 156 service provider's network. Internal more specific routes are not 157 exported to any external peer. 159 2.6. Special Purpose Routes 161 Special purpose routes are those routes which do not fall into any of 162 the other classes described here. In those cases in which such routes 163 need to be distinguished, a service provider may color such routes 164 with a unique value. Examples of special purpose routes include 165 anycast routes, and routes for overlay networks. 167 2.7. Upstream Routes 169 Upstream routes are typically learned from upstream service provider 170 as part of a transit service contract executed with the upstream 171 provider. 173 2.8. National Routes 175 These are route sets that are sourced from and/or received within a 176 particular country. 178 2.9. Regional Routes 180 Several global backbones implement regional policy based on their 181 deployed footprint, and on strategic and business imperatives. 182 Service providers often have settlement free interconnections with an 183 AS in one region, and that same AS is a customer in another region. 184 This mandates use of regional routing, including community attributes 185 set by the network in question to allow easy discrimination among 186 regional routes. For example, service providers may treat a route set 187 received from another service provider in Europe differently than the 188 same route set received in North America, as it is common practice to 189 sell transit in one region while peering in the other. 191 3. RFC 1997 Community Encoding and Values 193 In this section we provide standardized RFC 1997 [RFC1997] community 194 values for the categories described above. RFC 1997 communities 195 encoded as BGP Type Code 8, and are treated as 32 bit values ranging 196 from 0x0000000 through 0xFFFFFFF. The values 0x0000000 through 197 0x0000FFFF and 0xFFFF0000 through 0xFFFFFFFF are reserved. 199 The best current practice among service providers is to use the high 200 order two octets to represent the providers AS number, and the low 201 order two octets to represent the classification of the route, as 202 depicted below: 204 0 1 2 3 205 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 1 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 | | | 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 where 16 bit AS number, and is the encoding of the 211 value. For example, the encoding 0x2A7C029A would represent the AS 212 10876 with value 666. 214 3.1. Community Values for BGP Data Collection 216 In this section we define the RFC 1997 community encoding for the 217 route types described above for use in BGP data collection. It is 218 anticipated that a service provider's internal community values will 219 be converted to these standard values for output to a route 220 collector. 222 This document follows the best current practice of using the basic 223 format :. The values for the route categories are 224 described in the following table: 226 Category Value 227 =============================================================== 228 Customer Routes :64500 229 Peer Routes :64510 230 Internal Routes :64520 231 Internal More Specific Routes :64530 232 Special Purpose Routes :64540 233 Upstream Routes :64550 234 Reserved :64551-65535 235 National and Regional Routes 236 Africa (AF) :0 237 Asia/Australia/Pacific (AP) :1 238 Antarctica (AQ) :2 239 Europe (EU) :3 240 Latin America/Caribbean islands (LAC) :4 241 North America (NA) :5 243 In the above table, the field contains the ISO-3166-2 encoding 244 of the country code [ISO-3166-2,RIS-ISO-3166], which is right- 245 justified (i.e., left zero-padded) in the field. For example, 246 the community 10876:10242 would represent a national route in AS 247 10876 from the Fiji Islands, since the Fiji Islands are in the AP 248 region (Region Code 1) and have ISO-3166-2 numeric country code 242. 249 That is: 251 0 1 2 3 252 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 1 253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 | 0x2A7C | 0x2802 | 255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 Finally, note that these categories are not intended to be mutually 258 exclusive, and multiple communities can be attached where 259 appropriate. 261 4. Extended Communities 263 In some cases, the encoding described in section 3.1 may clash with a 264 service provider's existing community assignments. Extended 265 communities [EXTCOMM] provide a convenient mechanism that can be used 266 to avoid such clashes. 268 The Extended Communities Attribute is a transitive optional BGP 269 attribute with the Type Code 16, and consists of a set of extended 270 communities of the following format: 272 0 1 2 3 273 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 1 274 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 275 | Type high | Type low(*) | | 276 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Value | 277 | | 278 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 280 For purposes of BGP data collection, we encode the communities 281 described in section 3.1 using the two-octet AS specific extended 282 community type, which has the following format: 284 0 1 2 3 285 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 1 286 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 287 | 0x00 | Sub-Type | Global Administrator | 288 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 289 | Local Administrator | 290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 292 The two-octet AS specific extended community attribute encodes the 293 service provider's two octet Autonomous System number assigned by 294 IANA in the Global Administrator field, and the Local Administrator 295 field may encode any information. 297 This document assigns Sub-Type 0x05 for BGP data collection, and 298 specifies that the field, as defined in section 3.1, is 299 carried in the low order octets of the Local Administrator field. The 300 two high order octets of the Local Administrator field are reserved, 301 and are set to 0x00 when sending and ignored upon receipt. 303 For example, the extended community encoding for 10876:10242 304 (representing a national route in AS 10876 from the Fiji Islands) 305 would be: 307 0 1 2 3 308 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 1 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 310 | 0x00 | 0x05 | 0x2A7C | 311 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 312 | 0x00 | 0x00 | 0x2802 | 313 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 315 5. Intellectual Property 317 The IETF takes no position regarding the validity or scope of any 318 intellectual property or other rights that might be claimed to 319 pertain to the implementation or use of the technology described in 320 this document or the extent to which any license under such rights 321 might or might not be available; neither does it represent that it 322 has made any effort to identify any such rights. Information on the 323 IETF's procedures with respect to rights in standards-track and 324 standards-related documentation can be found in BCP-11 [RFC2028]. 325 Copies of claims of rights made available for publication and any 326 assurances of licenses to be made available, or the result of an 327 attempt made to obtain a general license or permission for the use of 328 such proprietary rights by implementors or users of this 329 specification can be obtained from the IETF Secretariat. 331 The IETF invites any interested party to bring to its attention any 332 copyrights, patents or patent applications, or other proprietary 333 rights which may cover technology that may be required to practice 334 this standard. Please address the information to the IETF Executive 335 Director. 337 6. Acknowledgments 339 Joe Abley, Randy Bush, Sean Donelan, Xenofontas Dimitropoulos, Vijay 340 Gill, John Heasley, Geoff Huston, Steve Huter, Olivier Marce, Ryan 341 McDowell, Rob Rockell, Rob Thomas, and Patrick Verkaik all made many 342 insightful comments on early versions of this draft. Henk Uijterwaal 343 suggested the use of the ISO-3166-2 country codes. 345 7. Security Considerations 347 While this document introduces no additional security considerations 348 into the BGP protocol, the information contained in the communities 349 defined in this document may in some cases reveal network structure 350 that was not previously visible outside the provider's network. As a 351 result, care should be taken when exporting such communities to route 352 collectors. Finally, routes exported to a route collector SHOULD also 353 be tagged with the NO_EXPORT community (0xFFFFFF01). 355 7.1. Total Path Attribute Length 357 The communities described in this document are intended for use on 358 egress to a route collector. Hence an operator may choose to 359 overwrite its internal communities with the values specified in this 360 document when exporting routes to a route collector. However, 361 operators should in general ensure that the behavior of their BGP 362 implementation is well-defined when the addition of an attribute 363 causes a PDU to exceed 4096 octets. For example, since it is common 364 practice to use community attributes to implement policy (among other 365 functionality such as allowing customers to set attributes such as 366 LOCAL_PREF), the behavior of an implementation when the attribute 367 space overflows is crucial. Among other behaviors, an implementation 368 might usurp the intended attribute data or otherwise cause 369 indeterminate failures. These behaviors can result in unanticipated 370 community attribute sets, and hence result in unintended policy 371 implications. 373 8. IANA Considerations 375 This document assigns a new Sub-Type for the AS specific extended 376 community type. In particular, the IANA should assign Sub-type 0x05, 377 using the "First Come First Served" policy defined in RFC 2434 378 [RFC2434], for the Sub-Type defined in Section 4. This corresponds to 379 a Type Field value of 0x0005. 381 9. References 383 9.1. Normative References 385 [EXTCOMM] Sangali, S., D. Tappan and Y. Rekhter, "BGP 386 Extended Communities Attribute", 387 draft-ietf-idr-bgp-ext-communities-06.txt, 388 Work in Progress. 390 [HOUSTON] Huston, G., "Interconnection, Peering, and 391 Settlements", 392 http://www.isoc.org/inet99/proceedings/1e/1e_1.htm 394 [ISO-3166-2] http://www.iso.org/iso/en/prods-services/iso3166ma/index.html 396 [RIS] "Routing Information Service", http://www.ripe.net/ris 398 [RIS-ISO-3166] ftp://ftp.ripe.net/iso3166-countrycodes.txt 400 [ROUTEVIEWS] "The Routeviews Project", http://www.routeviews.org 402 [RFC1771] Rekhter, Y., and T. Li (Editors), "A Border 403 Gateway Protocol (BGP-4)", RFC 1771, March, 404 1995. 406 [RFC1997] Chandra, R. and P. Traina, "BGP Communities 407 Attribute", RFC 1997, August, 1996. 409 [VLPS] Kompella, K., et. al., "Virtual Private LAN 410 Service", draft-ietf-l2vpn-vpls-bgp-00.txt, 411 Work in Progress. 413 [WANG] Wang, F. and L. Gao, "Inferring and Characterizing 414 Internet Routing Policies", ACM SIGCOMM Internet 415 Measurement Conference 2003. 417 9.2. Informative References 419 [RFC2119] Bradner, S., "Key words for use in RFCs to 420 Indicate Requirement Levels", RFC 2119, March, 421 1997. 423 [RFC2026] Bradner, S., "The Internet Standards Process -- 424 Revision 3", RFC 2026/BCP 9, October, 1996. 426 [RFC2028] Hovey, R. and S. Bradner, "The Organizations 427 Involved in the IETF Standards Process", RFC 428 2028/BCP 11, October, 1996. 430 [RFC2434] Narten, T., and H. Alvestrand, "Guidelines for 431 Writing an IANA Considerations Section in RFCs", 432 RFC 2434/BCP 26, October 1998. 434 10. Author's Addresses 436 D. Meyer 438 Email: dmm@1-4-5.net 440 11. Full Copyright Statement 442 Copyright (C) The Internet Society (2003). All Rights Reserved. 444 This document and translations of it may be copied and furnished to 445 others, and derivative works that comment on or otherwise explain it 446 or assist in its implementation may be prepared, copied, published 447 and distributed, in whole or in part, without restriction of any 448 kind, provided that the above copyright notice and this paragraph are 449 included on all such copies and derivative works. However, this 450 document itself may not be modified in any way, such as by removing 451 the copyright notice or references to the Internet Society or other 452 Internet organizations, except as needed for the purpose of 453 developing Internet standards in which case the procedures for 454 copyrights defined in the Internet Standards process must be 455 followed, or as required to translate it into languages other than 456 English. 458 The limited permissions granted above are perpetual and will not be 459 revoked by the Internet Society or its successors or assigns. 461 This document and the information contained herein is provided on an 462 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 463 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 464 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 465 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 466 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.