Global Routing Operations J. Snijders Internet-Draft NTT Communications Intended status: Standards Track June 4, 2019 Expires: December 6, 2019 BGP Well-known Large Communities draft-snjiders-bgp-wk-lc-00 Abstract This document describes well-known BGP Large Communities [RFC8092] akin to those of BGP Communities [RFC1997]. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months 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." This Internet-Draft will expire on December 6, 2019. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents Snijders Expires December 6, 2019 [Page 1] Internet-Draft BGP Well-known Large Communities June 2019 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Taxonomy of Well-known BGP Large Communities . . . . . . . . 2 2.1. Well-known Global Administrator . . . . . . . . . . . . . 2 2.2. Local Data Part 1 . . . . . . . . . . . . . . . . . . . . 3 2.3. Local Data Part 2 . . . . . . . . . . . . . . . . . . . . 3 3. Well-known BGP Large Communities . . . . . . . . . . . . . . 3 3.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Applicable Uses . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction This document describes Well-known BGP Large Communities [RFC8092]. Well-known BGP Communities [RFC1997] have proven utility and Well- known BGP Large Communities have supplemental benefit because their greater capacity allows for an accompanying argument, such as a four- octet BGP ASN [RFC6793]. Furthermore, an IANA registry is created for these new Well-known Communities. 2. Taxonomy of Well-known BGP Large Communities BGP Large Communities [RFC8092] are entities of three four-octet values known as the Global Administrator, and Local Data Part 1 and 2. The use of each is defined below. 2.1. Well-known Global Administrator The Global Administrator (GA), or namespace identifier, is the BGP Autonomous System Number (ASN) that defined the significance of the subsequent Local Data Parts. Because ASN 0 is otherwise proscribed from use by [RFC7607] and discouraged by [RFC8092], it is opportune for prescription as the Well-known Community namespace identifier in Snijders Expires December 6, 2019 [Page 2] Internet-Draft BGP Well-known Large Communities June 2019 the GA field, and this document reserves it for this purpose. It is also an easily typed and obvious value for operator convenience. One might be inclined to suggest the use of 65535 or 4294967295 ([RFC7300]), which are also taboo. An Private Use ASN [RFC6996] or 23456 (AS_TRANS, [RFC4893]) might also come to mind. The authors feel that zero is more convenient than the first two and avoids conflict within an AS that might use the latter ASNs. 2.2. Local Data Part 1 This, the second field, is the Well-known Community value itself. In the parlance of [RFC8092], it is the function by which Local Data Part 2 is evaluated. 2.3. Local Data Part 2 This, the third field, is the argument of or to the Well-known Community. 3. Well-known BGP Large Communities This document defines the following Well-known BGP Large Communities, further described below. In all cases, the Global Administrator is zero. +-------------------+-------------------+-------------------------+ | Local Data Part 1 | Local Data Part 2 | description | +-------------------+-------------------+-------------------------+ | 0 | ASN | no-export from AS ASN | +-------------------+-------------------+-------------------------+ | 1 | ASN | do not export to AS ASN | +-------------------+-------------------+-------------------------+ Table 1: Well-known BGP Large Communities 3.1. Examples +---------------+---------------------------+ | Community | description | +---------------+---------------------------+ | 0:0:64496 | no-export from AS 64496 | +---------------+---------------------------+ | 0:1:65551 | do not export to AS 65551 | +---------------+---------------------------+ Table 2: Well-known BGP Large Community Examples Snijders Expires December 6, 2019 [Page 3] Internet-Draft BGP Well-known Large Communities June 2019 4. Applicable Uses Well-known BGP Large Communities are not intended to replace Well- known BGP Communities [RFC1997], nor well-known communities of other BGP community types that may evolve. Use the correct tool for the problem. By example, a routing policy concept that requires an argument that can be represented in 4-octets is appropriate, while replicating the [RFC1997] NO_EXPORT community would not. 5. Security Considerations This document does not change any existing security issues associated with BGP Large Communities nor of other BGP Community Attributes. In addition to the considerations expressed in [RFC8092], an Autonomous System (AS) that accepts, sends or forwards NLRI with Well-known BGP Large Communities must itself be aware of how these communities will implicitly or explicitly affect route selection. 6. IANA Considerations IANA is requested to create a new registry for Well-known BGP Large Communities [RFC8092] by the name "BGP Well-known Large Communities". The registry MUST have two fields, Local Data Part 1 and Local Data Part 2, and MUST be seeded with the values defined by this document in Table 1 of Section 3. The allocation policy for new entries is first come, first served for Local Data Part 1 values of 0 through 2147483647 (0 - 0x7fffffff) and "Standards Action" for 2147483648 through 4294967295 (0x80000000 - 0xffffffff). The Local Data Part 2 is an argument associated with a particular Local Data Part 1, whose value can be unspecified (any value), a single or range of values, or have an allocation policy set forth by a separate "Standards Action." Allocation of a large swath of Local Data Part 1 values to a single function or concept is NOT RECOMMENDED. Non-consecutive Allocation is NOT RECOMMENDED. 7. References 7.1. Normative References [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, . Snijders Expires December 6, 2019 [Page 4] Internet-Draft BGP Well-known Large Communities June 2019 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS Number Space", RFC 4893, DOI 10.17487/RFC4893, May 2007, . [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet Autonomous System (AS) Number Space", RFC 6793, DOI 10.17487/RFC6793, December 2012, . [RFC6996] Mitchell, J., "Autonomous System (AS) Reservation for Private Use", BCP 6, RFC 6996, DOI 10.17487/RFC6996, July 2013, . [RFC7300] Haas, J. and J. Mitchell, "Reservation of Last Autonomous System (AS) Numbers", BCP 6, RFC 7300, DOI 10.17487/RFC7300, July 2014, . [RFC7607] Kumari, W., Bush, R., Schiller, H., and K. Patel, "Codification of AS 0 Processing", RFC 7607, DOI 10.17487/RFC7607, August 2015, . [RFC8092] Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas, I., and N. Hilliard, "BGP Large Communities Attribute", RFC 8092, DOI 10.17487/RFC8092, February 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 7.2. Informative References [RFC8195] Snijders, J., Heasley, J., and M. Schmidt, "Use of BGP Large Communities", RFC 8195, DOI 10.17487/RFC8195, June 2017, . Author's Address Snijders Expires December 6, 2019 [Page 5] Internet-Draft BGP Well-known Large Communities June 2019 Job Snijders NTT Communications Theodorus Majofskistraat 100 Amsterdam 1065 SZ The Netherlands Email: job@ntt.net Snijders Expires December 6, 2019 [Page 6]