--- 1/draft-ietf-grow-collection-communities-02.txt 2006-02-04 23:23:56.000000000 +0100 +++ 2/draft-ietf-grow-collection-communities-03.txt 2006-02-04 23:23:56.000000000 +0100 @@ -1,18 +1,18 @@ INTERNET-DRAFT D. Meyer -draft-ietf-grow-collection-communities-02.txt +draft-ietf-grow-collection-communities-03.txt Category Best Current Practice -Expires: July 2004 January 2004 +Expires: September 2004 March 2004 BGP Communities for Data Collection - + Status of this Document This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. @@ -21,27 +21,22 @@ and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. - The key words "MUST"", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", - "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this - document are to be interpreted as described in RFC 2119 [RFC 2119]. - This document is a product of the GROW WG. Comments should be - addressed to the authors, or the mailing list at - grow@lists.uoregon.edu. + addressed to the authors, or the mailing list at grow@lists.uoregon.edu. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract BGP communities (RFC 1997) are used by service providers for many purposes, including tagging of customer, peer, and geographically originated routes. Such tagging is typically used to control the @@ -54,72 +49,80 @@ route collectors. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Peers and Peering . . . . . . . . . . . . . . . . . . . . . 5 2.2. Customer Routes . . . . . . . . . . . . . . . . . . . . . . 5 2.3. Peer Routes . . . . . . . . . . . . . . . . . . . . . . . . 5 2.4. Internal Routes . . . . . . . . . . . . . . . . . . . . . . 5 - 2.5. Internal More Specific Routes . . . . . . . . . . . . . . . 5 + 2.5. Internal More Specific Routes . . . . . . . . . . . . . . . 6 2.6. Special Purpose Routes. . . . . . . . . . . . . . . . . . . 6 2.7. Upstream Routes . . . . . . . . . . . . . . . . . . . . . . 6 2.8. National Routes . . . . . . . . . . . . . . . . . . . . . . 6 2.9. Regional Routes . . . . . . . . . . . . . . . . . . . . . . 6 3. RFC 1997 Community Encoding and Values . . . . . . . . . . . . 7 3.1. Community Values for BGP Data Collection. . . . . . . . . . 7 4. Extended Communities . . . . . . . . . . . . . . . . . . . . . 9 4.1. Four-octet AS specific extended communities . . . . . . . . 10 - 5. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 10 - 6. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 11 - 7. Security Considerations. . . . . . . . . . . . . . . . . . . . 12 - 7.1. Total Path Attribute Length . . . . . . . . . . . . . . . . 12 - 8. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 12 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 9.1. Normative References. . . . . . . . . . . . . . . . . . . . 13 - 9.2. Informative References. . . . . . . . . . . . . . . . . . . 13 - 10. Author's Addresses. . . . . . . . . . . . . . . . . . . . . . 14 - 11. Full Copyright Statement. . . . . . . . . . . . . . . . . . . 14 + 5. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 10 + 6. Security Considerations. . . . . . . . . . . . . . . . . . . . 12 + 6.1. Total Path Attribute Length . . . . . . . . . . . . . . . . 12 + 7. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 12 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 + 8.1. Normative References. . . . . . . . . . . . . . . . . . . . 13 + 8.2. Informative References. . . . . . . . . . . . . . . . . . . 13 + 9. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 14 + 10. Full Copyright Statement. . . . . . . . . . . . . . . . . . . 14 + 11. Intellectual Property . . . . . . . . . . . . . . . . . . . . 15 + 12. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 15 1. Introduction BGP communities [RFC1997] are used by service providers for many purposes, including tagging of customer, peer, and geographically originated routes. Such tagging is typically used to control the scope of redistribution of routes within a providers network, and to - it's customers and peers. Communities are also used for a wide - variety of other applications, such as allowing customers to set - attributes such as LOCAL_PREF [RFC1771] by sending appropriate - communities to their service provider. Other applications include - signaling various types of VPNs (e.g., VPLS [VPLS]), and carrying - link bandwidth for traffic engineering applications [EXTCOMM]. + its customers and peers. Communities are also used for a wide variety + of other applications, such as allowing customers to set attributes + such as LOCAL_PREF [RFC1771] by sending appropriate communities to + their service provider. Other applications include signaling various + types of VPNs (e.g., VPLS [VPLS]), and carrying link bandwidth for + traffic engineering applications [EXTCOMM]. With the advent of large scale BGP data collection [RIS,ROUTEVIEWS] (and associated research), it has become clear that the geographical and topological information, as well as the relationship the provider has to the source of a route (e.g., transit, peer, or customer), carried in such communities is essential for a deeper understanding of the global routing system. This document defines standard - communities for export to BGP route collectors. These communities are - not (necessarily) intended for internal use by service providers. - Rather, they are meant to mirror the information that many service - providers carry today, and to be a standardized representation of - that information. + communities for export to BGP route collectors. These communities + represent a significant part of information carried by service + providers as of this writing, and as such could be useful for + internal use by service providers. However, such use is beyond the + scope of this memo. Finally, those involved in BGP data analysis are + encouraged to verify with their data sources as to which peers + implement this scheme (as there is a large amount of existing data as + well as many legacy peerings). The remainder of this document is organized as follows. Section 2 provides both the definition of terms used as well as the semantics of the communities used for BGP data collection, and section 3 defines the corresponding encodings for RFC 1997 [RFC1997] communities. Finally, section 4 defines the encodings for use with extended communities [EXTCOMM]. + The key words "MUST"", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in RFC 2119 [RFC 2119]. + 2. Definitions In this section, we define the terms used and the categories of routes that may be tagged with communities. This tagging is often referred to coloring, and we refer to a route's "color" as its community value. The categories defined here are loosely modeled on those described in [WANG] and [HUSTON]. 2.1. Peers and Peering @@ -147,24 +150,24 @@ 2.4. Internal Routes Internal routes are those routes that a service provider originates and passes to its peers and customers. These routes are frequently taken out of the address space allocated to a provider. 2.5. Internal More Specific Routes Internal more specific routes are those routes which are frequently - used for circuit balancing purposes, IGP route reduction, and also - may correspond to customer services which are not visible outside the - service provider's network. Internal more specific routes are not - exported to any external peer. + used for circuit load balancing purposes, IGP route reduction, and + also may correspond to customer services which are not visible + outside the service provider's network. Internal more specific routes + are not exported to any external peer. 2.6. Special Purpose Routes Special purpose routes are those routes which do not fall into any of the other classes described here. In those cases in which such routes need to be distinguished, a service provider may color such routes with a unique value. Examples of special purpose routes include anycast routes, and routes for overlay networks. 2.7. Upstream Routes @@ -186,25 +189,25 @@ AS in one region, and that same AS is a customer in another region. This mandates use of regional routing, including community attributes set by the network in question to allow easy discrimination among regional routes. For example, service providers may treat a route set received from another service provider in Europe differently than the same route set received in North America, as it is common practice to sell transit in one region while peering in the other. 3. RFC 1997 Community Encoding and Values - In this section we provide standardized RFC 1997 [RFC1997] community - values for the categories described above. RFC 1997 communities - encoded as BGP Type Code 8, and are treated as 32 bit values ranging - from 0x0000000 through 0xFFFFFFF. The values 0x0000000 through - 0x0000FFFF and 0xFFFF0000 through 0xFFFFFFFF are reserved. + In this section we provide RFC 1997 [RFC1997] community values for + the categories described above. RFC 1997 communities encoded as BGP + Type Code 8, and are treated as 32 bit values ranging from 0x0000000 + through 0xFFFFFFF. The values 0x0000000 through 0x0000FFFF and + 0xFFFF0000 through 0xFFFFFFFF are reserved. The best current practice among service providers is to use the high order two octets to represent the providers AS number, and the low order two octets to represent the classification of the route, as depicted below: 0 1 2 3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | @@ -273,22 +276,22 @@ = Fiji Islands Country Code = 242 = 0011110010 so that the low order 16 bits look like 001000011110010 = 0x10F2. 0 1 2 3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0x2A7C | 0x10F2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - Note that a configuration language might have allow the specification - of this community as 10876:4338 (0x1F2 == 4338 decimal). + Note that a configuration language might allow the specification of + this community as 10876:4338 (0x1F2 == 4338 decimal). Finally, note that these categories are not intended to be mutually exclusive, and multiple communities can be attached where appropriate. 4. Extended Communities In some cases, the encoding described in section 3.1 may clash with a service provider's existing community assignments. Extended communities [EXTCOMM] provide a convenient mechanism that can be used @@ -312,23 +315,23 @@ 0 1 2 3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0x00 | Sub-Type | Global Administrator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Administrator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The two-octet AS specific extended community attribute encodes the - service provider's two octet Autonomous System number assigned by - IANA in the Global Administrator field, and the Local Administrator - field may encode any information. + service provider's two octet Autonomous System number (as assigned by + an Internet Routing Registry) in the Global Administrator field, and + the Local Administrator field may encode any information. This document assigns Sub-Type 0x05 for BGP data collection, and specifies that the field, as defined in section 3.1, is carried in the low order octets of the Local Administrator field. The two high order octets of the Local Administrator field are reserved, and are set to 0x00 when sending and ignored upon receipt. For example, the extended community encoding for 10876:4338 (representing a terrestrial national route in AS 10876 from the Fiji Islands) would be: @@ -349,162 +352,140 @@ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0x02 | 0x05 | Global Administrator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Global Administrator (cont.) | 0x10F2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ In this case, the 4 octet Global Administrator sub-field contains a 4-octets Autonomous System number assigned by the IANA. -5. Intellectual Property - - The IETF takes no position regarding the validity or scope of any - intellectual property or other rights that might be claimed to - pertain to the implementation or use of the technology described in - this document or the extent to which any license under such rights - might or might not be available; neither does it represent that it - has made any effort to identify any such rights. Information on the - IETF's procedures with respect to rights in standards-track and - standards-related documentation can be found in BCP-11 [RFC2028]. - Copies of claims of rights made available for publication and any - assurances of licenses to be made available, or the result of an - attempt made to obtain a general license or permission for the use of - such proprietary rights by implementors or users of this - specification can be obtained from the IETF Secretariat. - - The IETF invites any interested party to bring to its attention any - copyrights, patents or patent applications, or other proprietary - rights which may cover technology that may be required to practice - this standard. Please address the information to the IETF Executive - Director. - -6. Acknowledgments +5. Acknowledgments The community encoding described in this document germinated from an interesting suggestion from Akira Kato at WIDE. In particular, the idea would be to use the collection community values to select paths that would result in (hopefully) more efficient access to various services. For example, in the case of RFC 3258 [RFC3258] based DNS anycast service, BGP routers may see multiple paths to the same prefix, and others might be coming from the same origin with different paths, but others might be from different region/country (with the same origin AS). Joe Abley, Randy Bush, Sean Donelan, Xenofontas Dimitropoulos, Vijay Gill, John Heasley, Geoff Huston, Steve Huter, Olivier Marce, Ryan - McDowell, Rob Rockell, Rob Thomas, and Patrick Verkaik all made many - insightful comments on early versions of this draft. Henk Uijterwaal - suggested the use of the ISO-3166-2 country codes. + McDowell, Rob Rockell, Rob Thomas, Pekka Savola, and Patrick Verkaik + all made many insightful comments on early versions of this draft. + Henk Uijterwaal suggested the use of the ISO-3166-2 country codes. -7. Security Considerations +6. Security Considerations While this document introduces no additional security considerations into the BGP protocol, the information contained in the communities defined in this document may in some cases reveal network structure that was not previously visible outside the provider's network. As a result, care should be taken when exporting such communities to route - collectors. Finally, routes exported to a route collector SHOULD also + collectors. Finally, routes exported to a route collector should also be tagged with the NO_EXPORT community (0xFFFFFF01). -7.1. Total Path Attribute Length +6.1. Total Path Attribute Length The communities described in this document are intended for use on egress to a route collector. Hence an operator may choose to overwrite its internal communities with the values specified in this document when exporting routes to a route collector. However, operators should in general ensure that the behavior of their BGP implementation is well-defined when the addition of an attribute causes a PDU to exceed 4096 octets. For example, since it is common practice to use community attributes to implement policy (among other functionality such as allowing customers to set attributes such as LOCAL_PREF), the behavior of an implementation when the attribute space overflows is crucial. Among other behaviors, an implementation might usurp the intended attribute data or otherwise cause indeterminate failures. These behaviors can result in unanticipated community attribute sets, and hence result in unintended policy implications. -8. IANA Considerations +7. IANA Considerations This document assigns a new Sub-Type for the AS specific extended community type. In particular, the IANA should assign Sub-type 0x05, using the "First Come First Served" policy defined in RFC 2434 [RFC2434], for the Sub-Type defined in Section 4. This corresponds to a Type Field value of 0x0005. -9. References +8. References -9.1. Normative References +8.1. Normative References - [EXTCOMM] Sangali, S., D. Tappan and Y. Rekhter, "BGP - Extended Communities Attribute", - draft-ietf-idr-bgp-ext-communities-06.txt, + [EXTCOMM] Sangali, S., D. Tappan and Y. Rekhter, "BGP Extended Communities + Attribute", draft-ietf-idr-bgp-ext-communities-06.txt, Work in Progress. - [HOUSTON] Huston, G., "Interconnection, Peering, and - Settlements", - http://www.isoc.org/inet99/proceedings/1e/1e_1.htm - [ISO-3166-2] http://www.iso.org/iso/en/prods-services/iso3166ma/index.html - [RIS] "Routing Information Service", http://www.ripe.net/ris - [RIS-ISO-3166] ftp://ftp.ripe.net/iso3166-countrycodes.txt - [ROUTEVIEWS] "The Routeviews Project", http://www.routeviews.org - [RFC1771] Rekhter, Y., and T. Li (Editors), "A Border Gateway Protocol (BGP-4)", RFC 1771, March, 1995. [RFC1997] Chandra, R. and P. Traina, "BGP Communities Attribute", RFC 1997, August, 1996. - [VLPS] Kompella, K., et. al., "Virtual Private LAN - Service", draft-ietf-l2vpn-vpls-bgp-00.txt, - Work in Progress. - - [WANG] Wang, F. and L. Gao, "Inferring and Characterizing - Internet Routing Policies", ACM SIGCOMM Internet - Measurement Conference 2003. +8.2. Informative References -9.2. Informative References + [HUSTON] Huston, G., "Interconnection, Peering, and Settlements", + http://www.isoc.org/inet99/proceedings/1e/1e_1.htm [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March, 1997. [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", RFC 2026/BCP 9, October, 1996. [RFC2028] Hovey, R. and S. Bradner, "The Organizations Involved in the IETF Standards Process", RFC 2028/BCP 11, October, 1996. [RFC2434] Narten, T., and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434/BCP 26, October 1998. [RFC3258] Hardie, T., "Distributing Authoritative Name Servers via Shared Unicast Addresses", RFC 3258, April, 2002. -10. Author's Addresses + [RIS] "Routing Information Service", http://www.ripe.net/ris + + [ROUTEVIEWS] "The Routeviews Project", http://www.routeviews.org + + [VPLS] Kompella, K., et. al., "Virtual Private LAN + Service", draft-ietf-l2vpn-vpls-bgp-00.txt, + Work in Progress. + + [WANG] Wang, F. and L. Gao, "Inferring and Characterizing + Internet Routing Policies", ACM SIGCOMM Internet + Measurement Conference 2003. + +9. Author's Addresses D. Meyer Email: dmm@1-4-5.net -11. Full Copyright Statement +10. Full Copyright Statement - Copyright (C) The Internet Society (2004). All Rights Reserved. + Copyright (C) The Internet Society (2004). This document is subject + to the rights, licenses and restrictions contained in BCP 78 and + except as set forth therein, the authors retain all their rights. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of @@ -515,10 +496,39 @@ The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + +11. Intellectual Property + + The IETF takes no position regarding the validity or scope of any + Intellectual Property Rights or other rights that might be claimed to + pertain to the implementation or use of the technology described in + this document or the extent to which any license under such rights + might or might not be available; nor does it represent that it has + made any independent effort to identify any such rights. Information + on the procedures with respect to rights in RFC documents can be + found in BCP 78 and BCP 79. + + Copies of IPR disclosures made to the IETF Secretariat and any + assurances of licenses to be made available, or the result of an + attempt made to obtain a general license or permission for the use of + such proprietary rights by implementers or users of this + specification can be obtained from the IETF on-line IPR repository at + http://www.ietf.org/ipr. + + The IETF invites any interested party to bring to its attention any + copyrights, patents or patent applications, or other proprietary + rights that may cover technology that may be required to implement + this standard. Please address the information to the IETF at ietf- + ipr@ietf.org. + +12. Acknowledgement + + Funding for the RFC Editor function is currently provided by the + Internet Society.