Re: [nsp] about routing

From: Dorian R. Kim (dorian@blackrose.org)
Date: Tue Feb 03 1998 - 21:25:54 EST


On Tue, Feb 03, 1998 at 04:55:13PM -0900, Todd Nagengast - Systems Wrangler wrote:
> I can't speak for any of the other methods with empirical data, but I can
> tell you that for a true split the bits bandwidth type of load sharing,
> eBGP doesn't seem to do a very good job. We're currently trying to do it
> with UUnet over two FR T1s. The routes will get cached on the FR subinterface
> and then all traffic for the cached route will go out that interface.

A mistake often made in looking at various way to load share/balance
parallel links is that people assume that it's a routing protocol feature.

While modern routing protocols do support _routing_ over equal cost
paths, it's the forwarding mechanism that determines the load sharing.

The per-packet load sharing done in D/CEF is probably what folks are
looking for, but it has a draw back in the sense that it can cause out of
order packet arrivals and compromise the end to end performance.

-dorian



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