If every RR plane must send a path, then the clients
will have N paths for every destination, even if there
is only one path.

Given N RR planes,
that means clients will need N times the BGP memory
and N times the BGP processing power for destinations
with only one path.

Please make a recommendation on how many RR planes
are optimal.

--
Jakob Heitz.
 

> -----Original Message-----
> From: Robert Raszuk [mailto:[email protected]] 
> Sent: Saturday, March 26, 2011 1:48 AM
> To: Jakob Heitz
> Cc: [email protected]
> Subject: Re: [GROW] Potential route flap with bgp-diverse-path
> 
> Hi Jakob,
> 
>  > Suppose 2 RR planes, plane1 advertises the best path
>  > and plane2 advertises the second best.
>  >
>  > If there is no second best, does plane2 advertise nothing?
> 
> Yes it would advertise overall best if backup is missing.
> 
>  > Suppose it does.
> 
> Ok.
> 
>  > Suppose there are 2 paths to a destination.
>  > P1 is best and P2 second best.
>  > Now P1 goes down.
>  > Plane1 will change its advertisement to P2.
>  > Plane2 will withdraw P2.
> 
> No.
> 
> The overall assumption is that all RRs keep all paths. So 
> plane 1 will 
> advertise P2 and plane 2 will do nothing if P1 goes down as 
> it already 
> advertised P2 to the client.
> 
>  > If the RR client receives and processes the withdrawal
>  > first, it will flap.
> 
> No withdraw will happen.
> 
> Cheers,
> R.
> 
>  > Note, the messages are asynchronous. Even if plane1
>  > sends his message first, the client can still process
>  > the message from plane2 first.
>  >
>  > A solution would be to delay any advertisements from
>  > the second-best plane by an interval greater than the MRAI
>  > timer. Not good, but I can't think of anything better.
>  >
>  > --
>  > Jakob Heitz.
>  >
>  > _______________________________________________
>  > GROW mailing list
>  > [email protected]
>  > https://www.ietf.org/mailman/listinfo/grow
>  >
> 
> 
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