who gets a /32 [Re: IPV6 renumbering painless?]

Sun Nov 21 03:35:00 UTC 2004

Thus spake "Barney Wolff" <barney at databus.com>
> Perhaps it is time to replace TCP with SCTP, where multihoming is not
> incompatible with PA addressing.  If done as a socket shim, so 
> applications
> don't have to be aware of it unless they want to be, it would appear to
> solve all of these problems.
>
> How much would it add to the pain of the v4-v6 transition, to just bite
> the bullet and do tcp-sctp at the same time?  I'd sure rather be a
> network troubleshooter going through that than living with NAT forever.

Almost no host OSes support SCTP today, which is the major barrier; it took 
a decade to get IPv6 widely implemented in hosts, and there's no reason to 
think SCTP implementation would be as fast or faster.

That aside, SCTP sockets and TCP sockets are not created the same way nor 
behave the same way from the application's view.  An API change would be 
needed to make this transparent to apps.  Also, there's no way for one host 
to know if another supports SCTP _and_ is running SCTP-capable apps without 
actually attempting a connection, which costs time.

It seems easier to try to back-port SCTP's multihoming features to TCP 
somehow than to deploy an entirely new transport protocol.  It's unfortunate 
this wasn't addressed at the time IPng was being designed.

S

Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking 