[c-nsp] BGP Cease - Connection collision resolution

[Christophe Fillot]

Paul Stewart wrote:

Hi,
> On a peering session we started getting the following:
>
>  
>
> %BGP-3-NOTIFICATION: received from neighbor 198.32.XXX.XX 6/7 (cease) 0
> bytes
>
>  
>
> This all started when we "upgraded" to 12.2(18)SXF16 it seems or at least
> the timeline matches up..
>
>  
>
> So, I've discovered that 6/7 means "Connection collision resolution" - does
> anyone know what that means in English? ;)  We have rebuilt our session and
> the peer has done the same thing.  a Google search tells me what it means by
> definition but no real solution.
>
>  
>   
 From RFC 4271:

6.8.  BGP Connection Collision Detection

   If a pair of BGP speakers try to establish a BGP connection with each
   other simultaneously, then two parallel connections well be formed.
   If the source IP address used by one of these connections is the same
   as the destination IP address used by the other, and the destination
   IP address used by the first connection is the same as the source IP
   address used by the other, connection collision has occurred.  In the
   event of connection collision, one of the connections MUST be closed.

[...]

   Closing the BGP connection (that results from the collision
   resolution procedure) is accomplished by sending the NOTIFICATION
   message with the Error Code Cease.