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