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RFC 2042 INFORMATIONAL ROUTING · BGP

Registering New BGP Attribute Types

How new BGP attribute type codes were to be documented and assigned.

On rfc-editor.org ↗
PUBLISHED
January 1997
AUTHORS
B. Manning
STREAM
Legacy
DEVELOPMENT VALUE
Octet 255
DOI
10.17487/RFC2042
ERRATA
Reported errata

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗ 
Network Working Group                                         B. Manning
Request for Comments: 2042                                           ISI
Category: Informational                                     January 1997


                  Registering New BGP Attribute Types

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Process:

   This document describes the process for creating new BGP attribute
   type codes.  Basic attribute type codes are described in RFC 1771,
   pages 12 through 15.  These, and new attribute type codes that are
   used in the Internet are registered with the IANA.

   The actual process will involve the documentation of such attribute
   type codes in an RFC.  There is no intention of segmenting the code
   space into public/private or IP/OSI or any other sectioning.

   As each attribute type code is in the process of being developed, it
   will use an octet value of 255, which will be reserved for this use.
   At the time an attribute type code is assigned a number by the IANA,
   the documetnation and code base will be updated to reflect the
   authorized attribute type code value.

   IANA maintained values will be published in the periodically updated
   Assigned Numbers RFC [6].  Requests for assignment of a new attribute
   type code should be sent to the IANA (IANA@IANA.ORG) with a subject
   that includes the phrase "BGP Attribute Type".

   Currently in use attribute type codes are listed below:

                 Value      Code                             Reference

                   1       ORIGIN                                  [1]
                   2       AS_PATH                                 [1]
                   3       NEXT_HOP                                [1]
                   4       MULTI_EXIT_DISC                         [1]
                   5       LOCAL_PREF                              [1]
                   6       ATOMIC_AGGREGATE                        [1]
                   7       AGGREGATOR                              [1]
                   8       COMMUNITY                               [2]
                   9       ORIGINATOR_ID                           [3]
                   10      CLUSTER_LIST                            [3]
                   11      DPA                                     [4]
                   12      ADVERTISER                              [5]
                   13      RCID_PATH / CLUSTER_ID                  [5]
                   ...
                   255     reserved for development



Security Considerations

   Security issues are not discussed in this memo.

References

   [1] Rekhter, Y., and Li, T., "A Border Gateway Protocol 4 (BGP-4)",
       RFC 1771, March 1995.

   [2] Chandra, R., Traina, P., and T. Li, "BGP Communities
       Attribute", RFC 1997, August 1996.

   [3] Bates, T., Chandra, R, "BGP Route Reflection An alternative
       to full mesh IBGP", RFC 1998, June 1996.

   [4] Chen, E., Bates, T., "Destination Preference Attribute for BGP",
       Work in progress, March 1996.

   [5] Haskin, D., "A BGP/IDRP Route Server alternative to a full mesh
       routing", RFC 1863, October 1995.

   [6] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC 1700,
       ISI, October 1994.

Author's Address

   Bill Manning
   USC/ISI
   4676 Admiralty Way
   Marina del Rey, CA. 90292

   Phone: 01.310.822.1511
   EMail: bmanning@isi.edu

ISO Plain Language

On this page
PROBLEMBGP attribute type codes need coordinated assignment so that new attributes have documented numeric values.
MECHANISMThe memo says new attribute types are documented in an RFC, with octet 255 used during development and IANA assigning the final code.
REGISTRATION PROCESSRFC 2042 records an informational registration process and lists the attribute codes then in use.

§1BGP Attribute Type Codes

BGP uses attribute type codes to identify attributes carried with routing information. RFC 2042 says the basic codes were described in RFC 1771 and that codes used on the Internet are registered with IANA.

The memo describes how new attribute codes should be documented and assigned. It does not divide the code space into public, private, IP, or OSI portions.

Each BGP attribute has a number that identifies it. The memo says those numbers should be documented and registered centrally.

§2Developing and Registering a New Code

While a new attribute type is being developed, the memo reserves octet value 255 for that purpose. When IANA assigns a number, the documentation and code base are updated to use the authorized value.

Requests should go to IANA with “BGP Attribute Type” in the subject. The RFC says IANA-maintained values will appear in the periodically updated Assigned Numbers RFC.

Use 255 as a temporary development value. Once IANA assigns the official number, update the code and its documentation.

§3Codes Listed in the Memo

The memo lists attribute codes 1 through 13 in use at the time, including ORIGIN, AS_PATH, NEXT_HOP, COMMUNITY, and CLUSTER_LIST. It also lists 255 as reserved for development.

The list reflects this RFC's publication context. The memo does not discuss security issues.

The RFC includes a snapshot of BGP attribute codes then in use. It marks 255 as reserved for development.

§4References

[1]RFC 1771Rekhter, Y., and Li, T., "A Border Gateway Protocol 4 (BGP-4)", RFC 1771, March 1995.March 1995[2]RFC 1997Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, August 1996.August 1996[6]RFC 1700Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC 1700, ISI, October 1994.October 1994