RFC 4271, "A Border Gateway Protocol 4 (BGP-4)", January 2006

Note: This RFC has been updated by RFC 4724, RFC 6286, RFC 6608, RFC 6793, RFC 7606, RFC 7607, RFC 7705, RFC 8212, RFC 8654, RFC 9072, RFC 9687

Errata ID: 4493
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Bruno Decraene
Date Reported: 2015-10-06
Verifier Name: Alvaro Retana
Date Verified: 2016-07-14

Section 4.5 says:

      Message Header Error subcodes:

               1 - Connection Not Synchronized.
               2 - Bad Message Length.
               3 - Bad Message Type.

      OPEN Message Error subcodes:

               1 - Unsupported Version Number.
               2 - Bad Peer AS.
               3 - Bad BGP Identifier.
               4 - Unsupported Optional Parameter.
               5 - [Deprecated - see Appendix A].
               6 - Unacceptable Hold Time.

      UPDATE Message Error subcodes:

               1 - Malformed Attribute List.
               2 - Unrecognized Well-known Attribute.
               3 - Missing Well-known Attribute.
               4 - Attribute Flags Error.
               5 - Attribute Length Error.
               6 - Invalid ORIGIN Attribute.
               7 - [Deprecated - see Appendix A].
               8 - Invalid NEXT_HOP Attribute.
               9 - Optional Attribute Error.
              10 - Invalid Network Field.
              11 - Malformed AS_PATH.

It should say:

      Message Header Error subcodes:

               0 - Unspecific.
               1 - Connection Not Synchronized.
               2 - Bad Message Length.
               3 - Bad Message Type.

      OPEN Message Error subcodes:

               0 - Unspecific.
               1 - Unsupported Version Number.
               2 - Bad Peer AS.
               3 - Bad BGP Identifier.
               4 - Unsupported Optional Parameter.
               5 - [Deprecated - see Appendix A].
               6 - Unacceptable Hold Time.

      UPDATE Message Error subcodes:

               0 - Unspecific.
               1 - Malformed Attribute List.
               2 - Unrecognized Well-known Attribute.
               3 - Missing Well-known Attribute.
               4 - Attribute Flags Error.
               5 - Attribute Length Error.
               6 - Invalid ORIGIN Attribute.
               7 - [Deprecated - see Appendix A].
               8 - Invalid NEXT_HOP Attribute.
               9 - Optional Attribute Error.
              10 - Invalid Network Field.
              11 - Malformed AS_PATH.

Notes:

RFC 4271 defines a use and a name for Error subcode 0:
- §4.5 (any error code):
If no appropriate Error Subcode is defined, then a zero
(Unspecific) value is used for the Error Subcode field.

- §6.2 (OPEN error code):
If one of the Optional Parameters in the OPEN message is recognized,
but is malformed, then the Error Subcode MUST be set to 0
(Unspecific).

The "IANA Considerations" section would also need to be updated
accordingly (says "0 Reserved”). However, IANA has corrected the
corresponding registry at http://www.iana.org/assignments/bgp-parameters.

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