GEANT implementing "BGP Guard Time" on their Junipers (was: Route update stats)

["Christian Panigl, ACOnet/VIX/UniVie" <]

    Dear all,
    
    remembering the thread on "Route update stats" in December ?

    Specifically:
    
http://www.ripe.net/ripe/mail-archives/routing-wg/2002/msg00050.html

    Now Christophe Belmont, GEANT-NOC, together with Juniper found a
    solution and we successfully tested it:
    
    They implemented "BGP Guard Time" (Cisco like 30 seconds) and the
    result was impressive:
    
    The number of BGP update messages received from GEANT dropped by ~85%
    and the number of "flaps" seen from GEANT by ~75% !
    
    BGP guard time (30sec) means that updates are only sent to neighbors for
    prefixes which have stayed in the routing table for 30 seconds.  I'm
    sure you know the specific problem, that when a prefix is withdrawn in a
    meshed environment, lots of updates are sent from BGP entities which do
    think that they still have a (longer) path.  It may take quite some time
    until all these false updates are dying down.  Without this guard time a
    BGP speaker immediately forwards all those false updates to all peers.
    I guess that if you would globally disable BGP guard time (which
    fortunately is default ON=30seconds for Ciscos but apparently not for
    Junipers) quite some routers would collapse on these withdrawal
    aftermaths.  
    
    So my suggestion would be for all ISPs using Juniper routers: turn on
    "BGP Guard Time" (Cisco like 30 seconds).
    
    Christophe, probably you can post the details to the list !?
    
    Kind regards
    CP
    
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