BGP Med quesion

On 24.03.2005 00:40 Adam Landas wrote

If you are running CatOs try

sw003> (enable) clear tcp ? synlist Clear TCP Open SYN Received list estlist Clear TCP Current Established list tcplist Drop ALL TCP Connections!!!!

the 2nd one (estlist). That did the trick on one of my switches running CatOS 8.3(1)

Arnold

Since you specified in subject "Med" word I can assume that you meant about incoming traffic. First, you should be aware that if you're connected to two different ISP's, then MED won't do much for you since no ISP will adverise your MED outside of their own AS. If you're multihomed to the same ISP, then MED could have some influence, but not very significant.

You could play with AS path prepending to get some traffic balance but it is not an exact method at all. The thing I mean by this is that results you achive today maybe won't be the same tommorow when something (routing policy) changes on ANY AS on the Internet you talk to...

If you have more than one /24 blocks under your ASN, then you would have some more space to play with traffic balancing.

Again, I have to state that if you send traffic trough one ISP, it doesn't mean that it will come back (at least reply to that traffic) trough the same ISP.

If you really want to control just "sending", then you could do it in multiple ways.

If you accept full routes from the both of the providers, just put higher weight (or local preference or shorter AS prepending) to "most" of the routes you get from cheapest provider. I've said "most" because you'll have to play a little to get wanted ratio.

If you want just second ISP as failover, then you could just accept default routes from both of the providers and the route from the cheapest make more significant than the one that comes from other ISP.

There's a lot of ways to do this. Of course, YMMV.