BGP weight / adding hops

[eero888888]

Hi,

I have two carriers, yIPes and SBC. The problem is that yIPes connects a little differently, in that I connect to a yIPes router, which immediately connects to one of their ISP's. The net result is that all yIPes routes have an "extra hop" of sorts, the yIPes AS, even though they link directly with Williams and Level3. This means that by far most of my traffic is going to SBC, since it has fewer hops.

Example:

Net XYZ is directly connected to SBC and Williams. But SBC will say XYZ is two hops (SBC, XYZ), where as yIPes will say it's three hops (yIPes, Williams, XYZ).

Net result is that most of my traffic is going out via SBC.

So, how do I fake out my router to either:

1.) Add an extra hop to the SBC routes

2.) Delete the hops from the yIPes routes.

I don't want to necessarily add local preferences, since this would make all traffic go through yIPes. I just want to even the AS hops playing field.

[Harold Ritter]

You can prepend an additional AS to the routes received from SBC.

route-map addAS permit 10

set as-path prepend last-as 1

or

set as-path prepend

!

router bgp

nei route-map addAS in

Hope this helps,

[eero888888]

Perfect. Works like a charm. Thanks.

[Georg Pauwen]

Hello,

you could try AS Path prepending, which would add an extra AS (hop) to the routes received from your SBC. The configuration would look like this:

access-list 1 permit 0.0.0.0 255.255.255.255

route-map AS-PATH-PREPEND 10 permit

match ip address 1

set as-path-prepend 200

neighbor x.x.x.x route-map AS-PATH-PREPEND out

x.x.x.x would be the IP address of your SBC peer.

Can you try that and see if it works ?

Regards,

GP