anyone else seeing very long AS paths?

John van Oppen john at vanoppen.com
Mon Feb 16 11:57:18 CST 2009


I am also a bit leery of setting it much lower than the defaults due to
the possibility of filtering something my customers will care about...
I am not sure what the best strategy is but what really bit a couple of
our customers was their old IOSes that tore the sessions down.   I note
that most of our customers speaking BGP had no issue just three out of
about 25.


What do people think is a reasonable maximum as-path length to enforce
at ones edge?




John van Oppen
Spectrum Networks LLC
Direct: 206.973.8302
Main: 206.973.8300
Website: http://spectrumnetworks.us


-----Original Message-----
From: Leland E. Vandervort [mailto:leland at taranta.discpro.org] 
Sent: Monday, February 16, 2009 9:53 AM
To: Jon Lewis
Cc: John van Oppen; nanog at nanog.org
Subject: RE: anyone else seeing very long AS paths?


bgp maxas-limit has a default value of 75 if you don't include it
explicitly in the config so in this case it wouldn't have made much of a
difference.

L.


On Mon, 16 Feb 2009, Jon Lewis wrote:

> On Mon, 16 Feb 2009, John van Oppen wrote:
>
> > Yep we saw the same, every customer with old IOS had their sessions
die
> > to us at the same time...   That always makes for an interesting
time
> > when watching the NMS system...
>
> Is there a reason you don't use something like "bgp maxas-limit NN" on
> your transit sessions?
>
> We saw this too, but it stopped at our transit routers.  There was
> actually another a few days ago.
>
> Feb 13 18:46:07: %BGP-6-ASPATH: Long AS path 4323 1299 12887 12741
39412
> 39625 39625 39625 39625 39625 39625 39625 39625 39625 39625 39625
39625
> 39625 39625 39625 39625 39625 39625 39625 39625 39625 39625 39625
39625
> 39625 39625 39625 39625...
>
> Feb 16 11:24:53: %BGP-6-ASPATH: Long AS path 4323 3257 29113 47868
47868
> 47868 47868 47868 47868 47868 47868 47868 47868 47868 47868 47868
47868
> 47868 47868 47868 47868 47868 47868 47868 47868 47868 47868 47868
47868
> 47868 47868 47868 47868...
>
>
> ----------------------------------------------------------------------
>   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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