Re: Draft: PI addressing derived from AS numbers

["J. Noel Chiappa" <jnc@ginger.lcs.mit.edu>]

    > From: Eliot Lear <lear@cisco.com>

    > So what I'm getting from this discussion is that 8+8 is too late but
    > 16+16 is too large???

I would suggest that 16+16 be done not with a complete second IPv6 header,
but rather one of the routing headers (I forget the formal name). That would
make it somewhat smaller.

Anyway, why does header size matter that much? Those on slow links (< 56K)
will be using header compression anyway, so it doesn't really matter for them
since the average packet will have all that stuff compressed out anyway, and
for those on fast links, who cares about a few extra bytes?

Check out the average web page to see how many stupid little icons it has on
it, how many JavaScript files it loads, how many pop-up windows (with their
own images and Javascript) it loads, etc, etc. (Every Web page designer ought
to be sentenced by law to using a 28.8 modem for all their online access...
but I digress.)


    > I would agree that 16+16 is too large. How about 4+16?  

You mean, wrap an IPv6 packet in an IPv4 packet?

First, that would produce a packet of the exact same length as my suggestion
above (an IPv4 header is 20 bytes, after all).

It would have the advantage that it could be carried over existing
substrate. It would have the disadvantage that you'd be limited to a 32-bit
locator, something that's already causing us grief.

(And don't even *think* about moving some of the "local" topology
information into the IPv6 addresses, leaving only the "global" stuff in the
IPv4 header. Long architectural rant about why you don't spread
functionality across two namespaces left out, as an exercise to the reader.)

	Noel