Network Working Group P. Traina
Request for Comments: 1773 cisco Systems
Obsoletes: 1656 March 1995
Experience with the BGP-4 protocol
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.
The purpose of this memo is to document how the requirements for
advancing a routing protocol to Draft Standard have been satisfied by
Border Gateway Protocol version 4 (BGP-4). This report documents
experience with BGP. This is the second of two reports on the BGP
protocol. As required by the Internet Architecure Board (IAB) and
the Internet Engineering Steering Group (IESG), the first report will
present a performance analysis of the BGP protocol.
The remaining sections of this memo document how BGP satisfies
General Requirements specified in Section 3.0, as well as
Requirements for Draft Standard specified in Section 5.0 of the
"Internet Routing Protocol Standardization Criteria" document .
This report is based on the initial work of Peter Lothberg (Ebone),
Andrew Partan (Alternet), and several others. Details of their work
were presented at the Twenty-fifth IETF meeting and are available
from the IETF proceedings.
Please send comments to email@example.com.
The BGP protocol has been developed by the IDR (formerly BGP) Working
Group of the Internet Engineering Task Force. I would like to
express deepest thanks to Yakov Rekhter and Sue Hares, co-chairs of
the IDR working group. I'd also like to explicitly thank Yakov
Rekhter and Tony Li for the review of this document as well as
constructive and valuable comments.
Traina [Page 1]RFC 1773 Experience with the BGP-4 Protocol March 1995
BGP is an inter-autonomous system routing protocol designed for
TCP/IP internets. Version 1 of the BGP protocol was published in RFC
1105. Since then BGP Versions 2, 3, and 4 have been developed.
Version 2 was documented in RFC 1163. Version 3 is documented in RFC
1267. The changes between versions 1, 2 and 3 are explained in
Appendix 2 of . All of the functionality that was present in the
previous versions is present in version 4.
BGP version 2 removed from the protocol the concept of "up", "down",
and "horizontal" relations between autonomous systems that were
present in version 1. BGP version 2 introduced the concept of path
attributes. In addition, BGP version 2 clarified parts of the
protocol that were "under-specified".
BGP version 3 lifted some of the restrictions on the use of the
NEXT_HOP path attribute, and added the BGP Identifier field to the
BGP OPEN message. It also clarifies the procedure for distributing
BGP routes between the BGP speakers within an autonomous system.
BGP version 4 redefines the (previously class-based) network layer
reachability portion of the updates to specify prefixes of arbitrary
length in order to represent multiple classful networks in a single
entry as discussed in . BGP version 4 has also modified the AS-
PATH attribute so that sets of autonomous systems, as well as
individual ASs may be described. In addition, BGP version for has
redescribed the INTER-AS METRIC attribute as the MULTI-EXIT
DISCRIMINATOR and added new LOCAL-PREFERENCE and AGGREGATOR
Possible applications of BGP in the Internet are documented in .
The BGP protocol was developed by the IDR Working Group of the
Internet Engineering Task Force. This Working Group has a mailing
list, firstname.lastname@example.org, where discussions of protocol features and
operation are held. The IDR Working Group meets regularly during the
quarterly Internet Engineering Task Force conferences. Reports of
these meetings are published in the IETF's Proceedings.
A BGP-4 Management Information Base has been published . The MIB
was written by Steve Willis (Wellfleet), John Burruss (Wellfleet),
and John Chu (IBM).
Apart from a few system variables, the BGP MIB is broken into two
tables: the BGP Peer Table and the BGP Received Path Attribute Table.
Traina [Page 2]RFC 1773 Experience with the BGP-4 Protocol March 1995
The Peer Table reflects information about BGP peer connections, such
as their state and current activity. The Received Path Attribute