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Re: IETF multihoming powder: just add IPv6 and stir
Christian,
On Friday, May 2, 2003, at 01:08 PM, Christian Huitema wrote:
Frankly, I don't believe that there is all that much value in the
so-called "GSE++" model. I see many shortfalls:
1) Rewriting addresses in the site exit routers deprives smart hosts
from the capacity to select their preferred return path;
To be sure I understand, you are saying that my laptop should have the
ability to make a decision as to what ISP Microsoft uses to route
packets back to me?
2) There is a lot of ambiguity as to whether the proposed identifiers
relate to an interface, a host or a session, and these choices lead to
extremely different trade-offs;
In the model I've tried to describe, everything from bit 48 to 127 is
handled identically as it is handled in the existing IPv6
specifications. Are you indicating those specifications have ambiguity
and that a specification for multi-homing should remove that ambiguity?
3) We know from previous discussion that 64 bits is too short for a
randomly assigned global space;
Sorry, must have missed this suggestion. Where would a random 64 bits
be used?
4) It is kind of too late to rewrite the TCP implementations that are
already out there.
In the model I've tried to describe, existing host IPv6 stacks would
require no changes whatsoever.
In fact, if we really want to go towards this independent identifier
path, I believe we should make it a session identifier, used by some
form of TCP++.
While I think TCP++ would be a lovely idea, I don't believe it is
realistic unless it incorporates backwards compatibility and if it
incorporates backwards compatibility, I don't see how you can get
multi-homing without either NAT or rewriting.
Using it for routing does not appear all that practical.
Eye of the beholder, I guess.
Rgds,
-drc