I'm probably doing this wrong but here goes. I have two isp providers a and b. I want to advertise my subnet toward provider a with a metric of 100 and toward b with a metric of 200. I point to a route map from the bgp neighbor statments which matches an access list for the advertised routeand set the metric. I know it is working on both routers because when I debug bgp updates I see the route go out with the metric set. However, if I go to a looking glass site I only see provider b (metric 200) instead of provider a (metric 100).
If you verified the prefix is being advertised but it doesn't show up in the internet root server(s) then you need to talk to the provider a, who isn't advertising it out to the internet. Provider a is probably filtering your prefix or they could be a customer of provider b and they might even be routing to your network through provider b and that could be why they mayn't be advertising your prefix.
I think we need to step back and remember some fundamentals of BGP. When you set metric you are setting the MED (Multi Exit Discriminator). The MED may be considered by your immediate neighbor - to whom you advertised it, but the MED is not passed beyond the immediate neighbor.
If my understanding of what Bill is attempting to do is to influence how traffic from the Internet gets routed back to him I believe that he should be looking at prepending his AS number rather than attempting to set the MED/metric. If I misunderstand then perhaps Bill can clarify.
As a side note I think that choice of terminology is very strange about set metric. It sort of implies that it is something that it is not.
Agreed about the MED and it's not the appropriate solution for this setup. It would be applicable solution if the customer was multi-homed to the same provider and MED can influence the path selection.
However, my point was provider a not advertising the customer prefix out to the Internet. Provider should be able to fix this since Bill had already verified the prefix is being advertised.
It seems to me that the fundamental position of the original post was that he was setting the metric and expected that to influence what he sees on the looking glass. And we need to deal first with the question of whether metric/MED is effective for this (and the answer is NO).
Beyond that if we want to investigate this issue I think that we need several details from Bill. What is his address space? Is it provider assigned addressing or is it provider independent addressing? What is the possibility that what he is advertising is being aggregated by one provider and the detail advertised by the other provider? Where is the looking glass (is it closer to one provider than the other (which might explain why it only sees one path - since BGP only chooses the best path when there are multiple possible paths))?
I think we need significant additional information to be able to understand and explain what is happening in this situation.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.