BGP Routing Issue

[hareskhan]

Experts,

I am running into a routing issue with a dual-home BGP setup with HSRP. I have two ISPs (ISP-A & ISP-B) and I'm following the setup showed in http://www.cisco.com/en/US/partner/tech/tk365/technologies_configuration_example09186a0080093f2c.shtml.

I have a T-1 from ISP-A and a DS3 from ISP-B and advertising my class C network block 192.168.1.0/24 (changed) to both ISPs. I want ISP-B to be preferred for inbound traffic for which I have appended my ASN 5 times on ISP-A. But the problem here is that ISP-B is advertising a 192.168.0.0/21 out to thier peers. And if the DS3 goes down, there will be a routing loop. Please advice.

Hares

[mheusinger]

Hello,

there is not much you can do except talking to the ISP causing you the problem.

BGP in your AS cannot be used to influence the route selection in the internet, because the two prefixes seen are not the same. So longest match will be the decider.

You are customer to ISP B and thus you should get his support (you are paying him for internet access, right?).

Regards, Martin