Appendix A. Comparison with RFC 1771

There are numerous editorial changes in comparison to [RFC1771] (too many to list here).

The following list the technical changes:

Changes to reflect the usage of features such as TCP MD5 [RFC2385], BGP Route Reflectors [RFC2796], BGP Confederations [RFC3065], and BGP Route Refresh [RFC2918].

Clarification of the use of the BGP Identifier in the AGGREGATOR attribute.

Procedures for imposing an upper bound on the number of prefixes that a BGP speaker would accept from a peer.

The ability of a BGP speaker to include more than one instance of its own AS in the AS_PATH attribute for the purpose of inter-AS traffic engineering.

Clarification of the various types of NEXT_HOPs.

Clarification of the use of the ATOMIC_AGGREGATE attribute.

The relationship between the immediate next hop, and the next hop as specified in the NEXT_HOP path attribute.

Clarification of the tie-breaking procedures.

Clarification of the frequency of route advertisements.

Optional Parameter Type 1 (Authentication Information) has been deprecated.

UPDATE Message Error subcode 7 (AS Routing Loop) has been deprecated.

OPEN Message Error subcode 5 (Authentication Failure) has been deprecated.

Use of the Marker field for authentication has been deprecated.

Implementations MUST support TCP MD5 [RFC2385] for authentication.

Clarification of BGP FSM.

RFC 4271 BGP-4 January 2006