nanog mailing list archives

Re: Persistent BGP peer flapping - do you care?


From: "Joel Baker" <lucifer () lightbearer com>
Date: Sun, 20 Jan 2002 14:02:15 -0700


On Thu, Jan 17, 2002 at 05:42:53PM -0500, Vijay Gill wrote:

On Thu, 17 Jan 2002, Dave Israel wrote:

It's a question of robustness; if the new spec includes a way to be
tolerant of how the spec is (or can be) commonly abused, then the
followers of the spec will not be at the mercy of those who deviate.

In this case, I think that having the option to keep a session that
gives bad routes up, and just dropping the route, is a good answer.
That would allow the user to determine which is preferable for a given
peer: possible corruption or certain disconnection.

If you have a "bad route" how do you know the rest of the update is good?
The nlri may have gotten corrupted on the wire or between the interface
and the processor (parity error, or some sort of corruption on the bus).
Given that case, in an update, I am not sure you can make a determination
of what is good nlri and selectively propogate and process those. See also
meltdowns circa nov 1998.

There was another notion that never made it off the drawing board (not even
into proposal) regarding "graceful error recovery", a way to assume that
your peer's *entire* table wasn't suspect, just the malformed part, and
notify the peer that there was a problem. Do this too many times, and you
drop the session, still, of course.

The not-even-a-formal-draft is still around somewhere.
-- 
***************************************************************************
Joel Baker                           System Administrator - lightbearer.com
lucifer () lightbearer com              http://users.lightbearer.com/lucifer/


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