Re: Time to revise RFC 1771

[Sean Donelan <sean () donelan com>]

On Tue, 26 June 2001, Clayton Fiske wrote:
> I don't object to the discussion of changing the RFC (whether I agree
> or not), and I accept that Vendor [everyone else except Cisco] having
> a knob for this would have prevented some routing disruptions for some
> networks. But then again, static routes would have prevented that too.
> It doesn't mean they're a good idea. What I object to is that people
> are using this particular case as justification for said discussion.

This is the third time a BGP protocol error has lead to repeated BGP
flapping across the Internet due to implementations aborting the BGP
session, restarting it, and aborting it over and over.

GATED, Bay Networks and now Vendor X have each had issues internetworking
with Cisco.  The particular cause varied, but the error handling in all
the cases resulted in severe route flaps across a substantial portion of
the net at the time.  It wasn't Cisco's fault all the time.  But what
was common was implementations following RFC's 1771 guidance that the
proper behaivor is to abort the BGP session.

If not now, when?

I would prefer we try to maintain the BGP sessions.  But if you think
your peer's protocol implementation is flawed, cycling the BGP session
is unlikely to fix the software.  It just makes things worse as you
announce and withdrawl sections of the route table repeatedly.  Shutdown
the session (and keep it down) and wait for human intervention.