What's with all the long aspaths?

Church, Charles cchurc05 at harris.com
Thu Oct 23 09:41:20 CDT 2008


Sounds like some automated scripts that didn't do any sanity checking.
Process pulls the current BGP table, checks for the longest path, and
then prepends the AS that many times to guarantee everyone takes the
other path.  But if two ISPs are doing this, well, the paths get longer
and longer.  I just checked our table for those ASs mentioned in your
log, they look short now.  Guess they caught it.

Chuck

-----Original Message-----
From: Jon Lewis [mailto:jlewis at lewis.org] 
Sent: Wednesday, October 22, 2008 11:17 PM
To: Mike Lewinski
Cc: nanog at nanog.org
Subject: Re: What's with all the long aspaths?


On Wed, 22 Oct 2008, Mike Lewinski wrote:

> I'm sure they get the attention of NOCs around the world as messages
like 
> this show up on consoles
>
> Oct 22 04:34:05 MDT: %BGP-6-BIGCHUNK: Big chunk pool request (306) for

> aspath. Replenishing with malloc

You might consider something like bgp maxas-limit 75 to exchange that
log 
message for the less scarey
Oct 22 06:34:09: %BGP-6-ASPATH: Long AS path ...

As an added bonus, you ignore their route while they're playing such 
games.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________





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