Subject: [OSPF] [Technical Errata Reported] RFC5340 (2046)

From: RFC Errata System <[email-masked]>
Date: Wed, 17 Feb 2010 12:45:00 -0800 (PST)

The following errata report has been submitted for RFC5340,
"OSPF for IPv6".

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=5340&eid=2046

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Type: Technical
Reported by: Acee Lindem <[email-masked]>

Section: 4.8.1

Original Text
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   o  In Step 2, when a router Vertex V has just been added to the
      shortest-path tree, there may be multiple LSAs associated with the
      router.  All router-LSAs with the Advertising Router set to V's
      OSPF Router ID MUST be processed as an aggregate, treating them as
      fragments of a single large router-LSA.  The Options field and the

Coltun, et al.              Standards Track                    [Page 45]
^L
RFC 5340                     OSPF for IPv6                     July 2008

      router type bits (bits Nt, V, E, and B) should always be taken
      from the router-LSA with the smallest Link State ID.

   o  Step 2a is not needed in IPv6, as there are no longer stub network
      links in router-LSAs.

   o  In Step 2b, if W is a router and the router-LSA V6-bit or R-bit is
      not set in the LSA options, the transit link W is ignored and V's
      next link is examined.

Corrected Text
--------------
   o  In Step 2, when a router Vertex V has just been added to the
      shortest-path tree and the router-LSA R-bit is not set in the
      LSA options, Vertex V's links are ignored and the next vertex on
      the candidate list should be examined as described in Step 3.

Coltun, et al.              Standards Track                    [Page 45]
^L
RFC 5340                     OSPF for IPv6                     July 2008

   o  Also In Step 2, when a router Vertex V has just been added to the
      shortest-path tree, there may be multiple LSAs associated with the
      router.  All router-LSAs with the Advertising Router set to V's
      OSPF Router ID MUST be processed as an aggregate, treating them as
      fragments of a single large router-LSA.  The Options field and the
      router type bits (bits Nt, V, E, and B) should always be taken
      from the router-LSA with the smallest Link State ID.

   o  Step 2a is not needed in IPv6, as there are no longer stub network
      links in router-LSAs.

   o  In Step 2b, if W is a router and the router-LSA V6-bit is not set
      in the LSA options, the transit link to W is ignored and V's next
      link is examined.

Notes
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This changes reflects the fact that the R-bit and the V6-bit should not be handled identically. The R-bit allows the router to participate in the IPv6 unicast topology but does not allow transit traffic. The V6-bit doesn't allow either. This problem was pointed out by Balaji Ganesh.

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RFC5340 (draft-ietf-ospf-ospfv3-update-23)
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Title               : OSPF for IPv6
Publication Date    : July 2008
Author(s)           : R. Coltun, D. Ferguson, J. Moy, A. Lindem
Category            : PROPOSED STANDARD
Source              : Open Shortest Path First IGP
Area                : Routing
Stream              : IETF
Verifying Party     : IESG