Subject: [OSPF] Further R-Bit clarification [Fwd: [Technical Errata Reported] RFC5340 (2046)]

From: Michael Barnes <[email-masked]>
Date: Fri, 26 Feb 2010 16:24:15 -0800

Hi Acee,

Another question regarding the R-bit. If V is the root of the SPF tree 
(e.g. it is the router doing the SPF) with the current rules it will not 
install any OSPF routes into its own RIB. I don't think this is really 
the behavior that is desired. If V is the root then don't we want to 
ignore the R-bit?

Thanks,
Michael

-------- Original Message --------
Subject: [OSPF] [Technical Errata Reported] RFC5340 (2046)
Date: Wed, 17 Feb 2010 12:45:00 -0800 (PST)
From: RFC Errata System <[email-masked]>
To: [email-masked], [email-masked], [email-masked], 
   [email-masked], [email-masked], [email-masked], 
    [email-masked], [email-masked]
CC: [email-masked], [email-masked]

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

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

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

Section: 4.8.1

Original Text
-------------
    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
-----
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.

Instructions:
-------------
This errata is currently posted as "Reported". If necessary, please
use "Reply All" to discuss whether it should be verified or
rejected. When a decision is reached, the verifying party (IESG)
can log in to change the status and edit the report, if necessary.

--------------------------------------
RFC5340 (draft-ietf-ospf-ospfv3-update-23)
--------------------------------------
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
_______________________________________________
OSPF mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/ospf

---

From: Rajesh Shetty <[email-masked]>
Date: Mon, 01 Mar 2010 11:35:26 +0530

Dear All,

Irrespective of whether V is root or not
V's Intra Area Prefix with reference type Router will get installed to the
RIB. But V's Intra Area Prefix with reference type Network will not get
installed, whether this behavior is as expected?

Thanks
Rajesh

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-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Michael Barnes
Sent: Saturday, February 27, 2010 5:54 AM
To: Acee Lindem
Cc: [email-masked]
Subject: [OSPF] Further R-Bit clarification [Fwd: [Technical Errata
Reported] RFC5340 (2046)]

Hi Acee,

Thanks,
Michael

-------- Original Message --------
Subject: [OSPF] [Technical Errata Reported] RFC5340 (2046)
Date: Wed, 17 Feb 2010 12:45:00 -0800 (PST)
From: RFC Errata System <[email-masked]>
To: [email-masked], [email-masked], [email-masked], 
   [email-masked], [email-masked], [email-masked], 
    [email-masked], [email-masked]
CC: [email-masked], [email-masked]

Section: 4.8.1

Original Text
-------------

Corrected Text
--------------

Notes
-----

Instructions:
-------------