Open Source BGP Route Optimization?

Fri May 28 22:48:32 UTC 2004

Bruce Pinsky <bep at whack.org> wrote:
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> Per Gregers Bilse wrote:
>
>> On May 28, 10:37am, "Sam Stickland" <sam_ml at spacething.org> wrote:
>>
>>> Are there any BGP extensions that would cause a BGP speaker to
>>> foward all of it's paths, not just it best? I believe quagga had
>>> made some recent attempts
>>
>>
>> It has been discussed and been on wish lists, but:
>>
>
> And as I said in my other post, there were two drafts submitted that
> never went anywhere.
>
>>
>>> in this direction. IIRC the problem isn't to do with the route
>>> annoucements, it's the route withdrawals. I believe BGP only
>>> specifies the prefix being withdrawn and not the path, so if it's
>>> advertised multiple paths to a prefix it's impossible to know which
>>> has been withdrawn.
>>
>>
>
> But the "optimizing" device is in need of receiving all potential
> paths from the border routers.  Essentially, it needs a complete
> picture of all viable paths, not just the best that each border has.
> It would not be advertising multiple paths.

No, that's not what I meant. I simply meant that the optimising device
couldn't just be a iBGP peer - it wouldn't get enough information. It occurs
to me now that walking the BGP4-MIB could be enough, but I'm wouldn't like
to bet on the efficently of detecting prefix withdrawals by constantly
rewalking the table!

To bring this back on topic, I imagine I'd be happy with a tool that simply
identified top traffic flows and automatically provided me with traceroute
and ping results. Though admittedly I'm not sure how useful it would end up
in real life, it sounds like it could be relatively useful tool in the hands
of a someone that understands it.

Thinking about the potential problems with it, I wonder if there could be
any milage in the idea of preformance beacons: Points at key points in an AS
(possibly registered in an RIR) that are garanteed to be useable for
prefined traffic metrics. Hmm.. maybe it's late and I haven't had enough
coffee - one of the route optimisation does something like this already?

Sam