bgp update destroying transit on redback routers ?

Alexandre Snarskii snar at
Thu Dec 1 16:38:03 UTC 2011

On Thu, Dec 01, 2011 at 05:07:15PM +0100, Igor Ybema wrote:
> Hi there,
> Since about 15:00u GMT we receive bgp updates from our transit which
> destroys the bgp sessions with them with message:
> send NOTIFICATION: 3/9 (update: optional attribute error) with 11 byte
> data. mxReadMs=610
> We use redback smartedge routers (SE100) currently for BGP.
> Anyone who have seen this also?

Have a complaint from our customer too. On our side (juniper) this is 
logged as: 

NOTIFICATION received from <peer-ip> (External AS <peer-as>): code 3 
(Update Message Error) subcode 9 (error with optional attribute), 
Data:  c0 07 08 00 00 00

As far as I can decode this attribute this is: 
c0: optional, transitive, no partial, no extended-length
08: attribute length is 8 bytes. 

I think attribute length may be a problem here, because per RFC

AGGREGATOR is an optional transitive attribute of length 6.

In theory, there is no difference between theory and practice. 
But, in practice, there is. 

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