Why doesn't BGP...

Ed Morin edm at halcyon.com
Sat Nov 9 18:27:34 UTC 1996

Well, at a minimum you can do a "bandwidth 44210" (or whatever) as part
of your router configuration to "tell" your router how fast it _can_ go.

How much of this _really_ gets passed on to other nodes via BGP sessions.
If you hear a route from 4 different links, aren't you simply passing on
to your neighbor (filters aside for the moment) that you "know how to
get to that net" regardless of which way you shove the packet at any
particular time?  That is, do you really pass on the destination link
info as well as the net info?

On Sat, 9 Nov 1996, Avi Freedman wrote:

> > Look, I can do a "show interface" on any interface and see what speed
> > it's running at and if it's dropping packets.  If BGP hears a route
> > on an interface that isn't dropping packets shouldn't _that_ route
> > be considered "best" all other things being equal (hop counts and
> > all)?  You can't tell me the router doesn't know this information
> > because _I_ get the information from the router itself!!
> > 
> > I understand about route instabilities, etc.  All I'm talking about
> > here is a better "tie breaker" than ordinate numbers of IP addresses.
> The router really can't see how fast an interface *can* go unless it's
> maxed out.  That's not really useful information in a route-selection
> decision.
> It's possible that the packet loss might weight a better path but you
> would have to be careful about reweighting 20k paths every few minutes...
> Especially if you pass those decisions on to other routers :)
> Avi

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

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