Re: [BEHAVE] proprietary implementation v.s standardisedprotocols//re: draft-xu-behave-nat-state-sync-00

> -----Original Message-----
> From: behave-bounces@ietf.org 
> [mailto:behave-bounces@ietf.org] On Behalf Of Simon Perreault
> Sent: Tuesday, December 01, 2009 11:16 AM
> To: Dan Wing
> Cc: behave@ietf.org
> Subject: Re: [BEHAVE] proprietary implementation v.s 
> standardisedprotocols//re: draft-xu-behave-nat-state-sync-00
> 
> Dan Wing wrote, on 2009-12-01 13:39:
> > My point is that it shouldn't make things worse.  If the functioning
> > NAT64's prefix changes and the old prefix no longer works, 
> that makes
> > things worse -- it effectively causes IPv6 addresses to 
> change.  That
> > breaks not just applications that are sensitive to IP 
> address changes, 
> > but also existing TCP sessions.  SCTP handles IP address changes
> > better, but there is scant deployment of SCTP yet (due to many 
> > reasons).
> 
> I don't understand where you're going.
> 
> There are two kinds of breakage:
> 
> 1. One NAT64 box in a cluster* dies. No impact beyond the 
> fact that you now have
> a dead box that needs replacing.
> 
> 2. A whole cluster dies. This is not pain-free, and it's not 
> designed to be.
> Suddenly, you need to redirect all clients to the new 
> Pref64::/n. There are
> known issues with that, but this event will happen rarely 
> enough that it's worth
> the risk.
> 
> If you're really afraid of breakage #2, you have to use 
> bigger clusters. But
> that has disadvantages too. It ends up being an operational 
> issue. Tradeoffs, etc.
> 
> Another idea: have another cluster "take over" the prefix of 
> the dead one. Use
> routing to redirect clients to the new cluster. Tradeoffs, 
> etc., again.
> 
> My point is that #2 doesn't need standardization. The 
> solutions are diverse and
> everyone will be dealing with it differently. On the other 
> hand, #1 is a well
> understood problem, with a well understood solution, with 
> various proprietary
> incarnations in use right now (hint! hint!).
> 
> 
> * Cluster = A set of synchronized NAT64 boxes sharing a 
> single Pref64::/n.

Agreed.  I think we were just mis-communicating between
the two types of breakage.  I had thought you were describing
breakage (1) as needing (or wanting) a new Pref64.

-d

> Cheers,
> Simon
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