Sam, On Fri, 18 March 2005 14:05:12 +0000, Sam Stickland wrote:
We're looking at doing outbound traffic values based on upstream ("tier1") MED values. But, of course, there's no standard for MED values. Assuming I can get definations from the upstreams as to what their MED values mean, I have to rebase them into a common range.
MEDs are pretty much always specific to the network advertising them. Some base them on round-trip-time, some on the pipe size (both IGP), and what not. To compare these is difficult to impossible I'd say myself.
However, a route-map (cisco, foundry) only allows you to set, add or subtract to an MED value, so this doesn't seem possible.
Is anyone doing this, and if so how?
Don't do it... MEDs are perfect when you have two links to the same provider and want to determine where to send him the traffic closest to the origin, but that's pretty much all you can/want to do with MEDs from your transit supplier. For peers you can of course use some pre- defined metrics and 'always-compare-med' or variants of it, to differentiate the type of peer, but that is not what you mean as I see it. Alexander