Re: about Area Splitting

[Acee Lindem <[e-mail]>]

Li, Ke Qin (Peter) wrote:

>Hi,
>
>        I've read the Internet Draft "OSPF Areas Considered Harmful" written
>by Mikkel Thorup
>http://www.ietf.org/internet-drafts/draft-thorup-ospf-harmful-00.txt. In
>Section 8.0 "Summarization and infinite loops", a scenario is described
>where area splitting results in infinite routing loop (although IMHO it is
>black hole).
>
Hi Kegin,

The traffic should result in an ICMP reject since any deployable
implementation will install a reject route corresponding
to its active area ranges that do not coincide with computed intra-area
routes. RFC 2328 doesn't state this explicitly but
it is implied by section 3.5 (it says a single route may be advertised
for an area range - this implies a route exists).

>I think it is a basic problem related to OSPF hierarchy and
>area range. Has this problem been discussed in this list before? If yes,
>what is the solution?
>
I'm not sure how serious the problem is since there haven't been that
many complaints. However, as
Sina points out, the proposed Tunnel Adjacency (TA) extension can be
used to repair a partitioned
non-backbone area.


>
>        Thank you very much!
>
>Keqin Li
>Bell Labs Research China
>Tel: [phone]-8438
>
>
>