anyone else seeing very long AS paths?

Jack Bates jbates at
Tue Feb 17 19:31:02 UTC 2009

Ivan Pepelnjak wrote:
> Classic IOS (I did not test XE, XR or NX) can handle inbound updates with AS
> path lengths above 255, but fails miserably when it has to send an oversized
> update (producing invalid BGP UPDATE message), resulting in a flapping BGP
> session (anyone who wants to test this behavior and report/fix this bug can
> get all the files needed to reproduce it).

Just to reconfirm. The issue arrives with sending an update, not 
receiving? So if an ISP does not have a limit and their IOS cannot 
handle this, they will send an invalid BGP UPDATE to the downstream 
peers causing them to reset regardless of their max as-path settings?

Just trying to reconfirm, so I can inform my customers if there was 
anything they could do to prevent it, or if it is actually their 
provider that instigated the peer reset by sending invalid updates.


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