Re: Why doesn't BGP...

[Ed Morin <edm () halcyon com>]

On Fri, 8 Nov 1996, Marten Terpstra wrote:

> Ed Morin <edm () halcyon com> writes
>
>  * Why doesn't BGP pick the link with the highest bandwidth, or, better
>  * yet, pick the link with the highest bandwidth AND least congestion to
>  * label as the "best" available route?  The needed information is avail-
>
> The first one is easy, in fact you can do that yourself by fiddling
> with metrics or such on the different BGP sessions. The second one
> would have dramatic consequences in terms of route instability. You
> pick one route now because of load on the link, the load changes and
> you pick the other, now BGP will have to change the announcement of
> this network to other peers. So, now we not only have flaps because of
> links/routers going up and down, we also have flap because of load
> changes on the network. The result: you are dampened out forever, or
> the network falls over.

Is this really true?  All I'm asking for is that the route a router
considers to be "best" be picked by something a little more rational
than the ordinate order of its IP address relative to another link.
I don't see a flap situation at all here -- only that a decision to
route a packet may change more frequently based on load.

Ed Morin
Northwest Nexus Inc. (206) 455-3505 (voice)
Professional Internet Services
edm () nwnexus WA COM

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