RFC 5185, "OSPF Multi-Area Adjacency", May 2008

Errata ID: 6506
Status: Rejected
Type: Technical
Publication Format(s) : TEXT
Reported By: Ketan Talaulikar
Date Reported: 2021-04-02
Rejected by: John Scudder
Date Rejected: 2021-05-17

Section 2.7 says:

   Multi-area adjacencies are announced as point-to-point links.  Once
   the router's multi-area adjacency reaches the FULL state, it will be
   added as a link type 1 to the Router Link State Advertisement (LSA)
   with:

      Link ID = Remote's Router ID

      Link Data = Neighbor's IP Address or IfIndex (if the underlying
      interface is unnumbered).

   Unlike numbered point-to-point links, no type 3 link is advertised
   for multi-area adjacencies.

It should say:

   Multi-area adjacencies are announced as point-to-point links.  Once
   the router's multi-area adjacency reaches the FULL state, it will be
   added as a link type 1 to the Router Link State Advertisement (LSA)
   with:

      Link ID = Remote's Router ID

      Link Data = Router interface's IP Address or IfIndex (if the underlying
      interface is unnumbered).

   Unlike numbered point-to-point links, no type 3 link is advertised
   for multi-area adjacencies.

Notes:

The encoding of Link Data as specified in RFC5185 is not consistent with the base OSPF specification in RFC2328. This has resulted in different behaviors in deployed implementations where some follow RFC2328 (i.e. the corrected text) while others follow the Original text of RFC5185 leading to interop issues.

More importantly, for implementations of RFC5185, it is not possible to determine the Neighbor's interface IfIndex unless some additional mechanisms (that have not been specified or referenced by RFC5185) are implemented - viz. RFC8510.

This topic has been discussed in the LSR WG recently and this errata is being raised to track this issue : https://mailarchive.ietf.org/arch/msg/lsr/iL85WkrqhI17wUrxd-WozMQvKtE/
--VERIFIER NOTES--
As discussed here (https://mailarchive.ietf.org/arch/msg/lsr/9IAkRCbZN39loWcwKjtNWfUW_qA/) this would be a technical change vs. the WG consensus when the document was progressed, and should be rejected (see https://www.ietf.org/about/groups/iesg/statements/processing-rfc-errata/ #7). The appropriate way to pursue this looks to be an update or bis.

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