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Re: draft-ietf-nat-protocol-complications-02.txt

2000-04-24 09:50:03
At 4:32 PM +0200 4/24/00, Sean Doran wrote:
Unfortunately, IPv6's current addressing architecture makes it very
difficult to do this sort of traditional multihoming if one is not
a TLA.  This is a significant step backward from the current IPv4
situation, where one can persuade various operators to accept
more-specific prefixes (coloured with appropriate community
attributes) in order to optimize return traffic from particular
parts of the Internet.

Sean,

That is widely claimed but incorrect.  Nothing in the IPv6 addressing
architecture prevents a user from negotiating with multiple operators
to accept any prefix assigned to that user.  IPv6 retains the same
capability as IPv4 in that respect.

Therefore, in order to support IPv6 house-network multihoming, so
as to preserve at least these three features of traditional
multihoming, either the current IPv6 addressing architecture's
restrictions on who can be a TLA must be abandoned (so each house
becomes a TLA),...

The consequences of those restrictions are not what you imagined, but
even so, making each house a TLA does not strike me as a scalable
multihoming solution for very large numbers of houses, given the current
state of the routing art.

...or NATs must be used to rewrite house-network addresses into various
PA address ranges supplied by the multiple providers.

That's not the only possible alternative, and it is an alternative that
creates a bunch of other unsolved problems (see earlier messages in this
thread).

IPv6's larger address space is merely a necessary piece of an 
Internet which will not run out of numbers.  

Wow, we actually agree on something!  (Though I could quibble over the
"merely".)

Steve