Re: Network layer reqt? [was Re: Transport level multihoming]

[xxvaf <xxvaf@mfnx.net>]

> Margaret Wasserman wrote:
> > 
> > >No. But today, connections with TCP/IPv4 and typical IP multi-homing get
> > >dropped and data gets lost when the prefered path fails. Traffic is lost
> > >until the routing reconverges which is usually long enough to back TCP off
> > >into oblivion.
> > 
> > Is this true?  Can other operators or admins of large sites
> > comment on this statement, in particular?
> 
> Well, we've had many anecdotes of very long (>100 seconds) BGP 
> convergence times- Abha reported on some actual *facts* in the 
> IETF plenary- see http://www.merit.edu/ipma/. TCP doesn't
> react well.

A point of clarification: traffic is not "lost" while routing reconverges;
individual IP packets are dropped and must be re-transmitted, but TCP's
reliable delivery mechanism ensures that traffic is not lost as long as the
session isn't reset.

	--Vince