Re: RE : RE : RE : Last call for draft-ietf-tewg-interarea-mpls-te-req-01.txt

Hi Tony,

At 02:39 AM 5/28/2004 -0700, Tony Li wrote:
>>No, computation can be distributed on ABRs. This is basically the 
>>scenario 4 of
>>draft-kompella-mpls-multiarea-te :
>>"The head-end LSR requests one of the ABRs in the head-end area to
>>    compute a path to the destination. When the ABR in the head-end area
>>    receives the request, the ABR requests one of the ABRs in the tail-
>>    end area to compute paths to the destination from all/some of the
>>    ABRs in the tail-end area. Once the ABR in the head-end area obtains
>>    this information from the ABR in the tail-end area, the ABR in the
>>    head-end area could compute the path through the head-end and the
>>    backbone areas, concatenates the results of this computation with the
>>    appropriate path through the tail-end area, and then return the
>>    result to the head-end LSR."
>
>
>Well, yes, that could be made to work.  Pretty ugly tho (sorry Kireeti ;-).
>
>Again, I'm happy to make the tradeoff of less work for less optimality.
>If I'm that concerned about optimality, then I'll do offline computation
>and static configuration.  Or human intervention.  I'm not interested in
>spending the rest of my life debugging an incredibly complex solution that
>gives me the last 0.0001% of optimality.

perfectly acceptable point of view of course. If optimality for 
inter-area/AS TE path is not required, just go ahead with ABR selection 
based on local knowledge but the point of the discussion was to mention 
that leaking of partial (topo) or summarized (TE-related) will always have 
an impact on your IGP and never guarantee you to get the shortest path.

JP.

>Tony
>
>