Re: Requirements [was Re: Transport level multihoming]

[Daniel Senie <dts@senie.com>]

Brian E Carpenter wrote:
> 
> Thanks Margaret for getting some precision into the discussion.
> 
> Margaret Wasserman wrote:
> 
> ...
> > Let's make a distinction between the ability to do two
> > things:
> >
> >          (a) Establish and use new upper layer communication
> >                  sessions (i.e. TCP connections).
> >          (b) Maintain existing upper layer communication sessions.
> >
> > Is it required that an existing IPv6 stack be able to do (a)
> > and/or (b) in the following site multi-homing situations?
> >
> >          (1)  When both (or all) of the multi-homed site's
> >               connections to the Internet are working?
> >
> >                  Obviously, we need (a) and (b) to work.
> >
> >          (2)  When one of the multi-homed site's connections to
> >               the Internet stops working?
> >
> >                  We need (a).  Do we need (b)?  Or is acceptable
> >                  to require host software updates to obtain
> >                  reliable connections in this situation?
> >
> My answer is no, it would be a very serious mistake to require (b)
> in this case. It would result in an undeployable solution.

Agree with Brian. Applications will have to deal with restarting
connections if they die. This is fairly common already, since the
IPv4/BGP multihoming world works this way.

It's ideal if the applications can get reconnected quickly, of course.
Ideally, we should be working toward having that failover time be as
little as possible. The present failover with IPv4/BGP/Multihoming isn't
all that good (and feels like it's getting worse over time).

-- 
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Daniel Senie                                        dts@senie.com
Amaranth Networks Inc.                    http://www.amaranth.com