Subject: [Mipshop] RE: figuring out P, I and V bits

From: Soliman Hesham <[email-masked]>
Date: Mon, 24 Nov 2003 10:23:02 -0500

> At most, this seems to be a binary decision (one bit, not three).

=> Yes that's possible.

 > My question is: if we assume ingress filtering is always one 
 > (as I believe
 > we should), then which bits (if any) are needed?

=> If we assume that there is no need to distinguish between
the case where the operator wants to force the MN to use
RCoA as a src and the case where the MN wants to use
RCoA as a src then I think we have two options:

A) No flags at all. The MN always reverse tunnel to the 
MAP, or,

	Pros : - The implementation is simpler because the 
            MN treats the RCoA as a temp HoA and the MAP
            as a temp HA.  

            - Less configurations in ARs to add another prefix
              to the ingress filter.

      Con: More overhead on the uplink (in the absence of
           header compression), which is usually more bandwidth
           limited than the downlink (in cellular systems).

B) One flag to tell the MN whether it MUST reverse tunnel
to the MAP when it uses RCoA as a src. 

      Pro : Less bandwidth used in the uplink (in the 
            absence of header compression).

      Cons : The implementation in the MN is slightly more
             complex.

            - More config in ARs to add the RCoA prefix(es).

I'm fine with either option. Both will involve minimal 
edits to the spec. It's probably easier to just do (A). 

Hesham

 > -gabriel

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From: gabriel montenegro <[email-masked]>
Date: Mon, 24 Nov 2003 17:51:28 +0100

That's a good summary, thanks Hesham. I've added it to the issue description
for issue 2.

-gabriel

-- 
Gabriel Montenegro (Sun Microsystems Laboratories, Europe)
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