draft-xie-stewart-sigtran-ddp-00 addresses redundancy and failover of
sessions within a server pool, where uncoordinated failover of sessions from
one endpoint to another is a requirement. There is signifcant overheard and
indirection added to the session to achieve this.
We seem to be discussing a simpler requirement: coordinated movement of a
session from one ip:port pair on a single endpoint to a different ip:port
pair on the same endpoint. Windows, buffer states, sequence numbers, etc.
could all remain the same.
I would think the latter requirement could be implemented as a simple TCP
"forward me" option. For ESP/AH-protected sessions, no TCP-level
anti-hijacking protection seems necessary. This could even be performed if
the original IP is suddenly not available and the other endpoint hasn't
given up on the connection yet; you send a "forward me" packet sourced from
the first IP, then listen for an ACK on the new IP.
I can think of no simple way (ie. without recreating IKE&AH inside TCP) to
do this for unprotected sessions; I'm not sure it's worth the effort to
solve either.
I'm sure there's something I'm missing here, or else this would have been
implemented 15 years ago... Thoughts?
S
| | Stephen Sprunk, K5SSS, CCIE #3723
:|: :|: Network Consulting Engineer, NSA
:|||: :|||: 14875 Landmark Blvd #400; Dallas, TX
.:|||||||:..:|||||||:. Email: ssprunk(_at_)cisco(_dot_)com
----- Original Message -----
From: ned(_dot_)freed(_at_)innosoft(_dot_)com
To: Karl Auerbach
Cc: IETF
Sent: Wednesday, April 26, 2000 16:48
Subject: RE: runumbering (was: Re: IPv6: Past mistakes repeated?)
Turn it any way you want, TCP sessions can only survive renumbering
through
end to end mechanisms...
Which raises the interesting (to me anyway) question: Is there value in
considering a new protocol, layered on top of TCP, but beneath new
applications, that provides an "association" the life of which transcends
the TCP transports upon which it is constructed?
I believe that if we had such a protocol that it would be a useful tool to
solve many of the juggling acts that transpire under the heading of
"mobile networking" as well as providing a way to continue (or
"resume") connectivity after IP address changes.
(I will, of course, be suitably embarrassed if someone points out that
work is already going on to do this.)
draft-xie-stewart-sigtran-ddp-00.txt
ned