nanog mailing list archives

Re: shim6 (was Re: IPv6 news)


From: bmanning () vacation karoshi com
Date: Fri, 14 Oct 2005 19:42:31 +0000


On Fri, Oct 14, 2005 at 12:33:51PM -0700, william(at)elan.net wrote:

On Fri, 14 Oct 2005 bmanning () vacation karoshi com wrote:

Since shim6 requires changes in protocol stacks on nodes, my
impression has been that it isn't a _site_ multihoming solution,
but rather a _node_ multihoming solution.  Is my impression incorrect?

There is no shortage of rough corners to file down, and I am behind
on my shim6 mail, but the general idea is to let end sites multi-home
in the "bag-o-PA-prefixes" style and let the nodes within that site
use their multiple globally-unique addresses (one per upstream, say)
to allow sessions to survive rehoming events.

    the kicker here is that the applications then need some
    serious smarts to do proper source address selection.

No. The kicker is that the applications needs no such smarts and
shim6 will take care of this for all applications on the system on
the network level.

        call me skeptical...  I last followed this line of      
        thinking w/ Rich Draves hammered out the issues of
        source address selection in his I-D's (and they might
        have become RFCs) and they are not trival.  vendors
        getting this right, let alone interoperable will be 
        a significant feat.  Handwaving and Tapdancing not
        withstanding.  Then there is the minor detail in
        a service provider figuring out what, if anything, she
        needs to do to migrate from the existing, timetested, working
        methods of multi homing to this new'nimproved method...

        reminds me of the old NewYorker cartoon; "...and then a miracle occurs..."

--bill



-- 
William Leibzon
Elan Networks
william () elan net


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