MPLS Service Proivider Migration

[Scott Hanson]

Hello everyone,

I have an MPLS with several sites all using BGP and all one 1 service provider.   I am thinking that if we want to migrate to another service provider 1 site at a time I can put a new router (on the new ISP network) at the "central site" feeding into the same switch stack as the existing router and when site A  needs to move to the new ISP that site should still be able to talk to the other sites on the old ISP as long as BGP is configured correctly. I just have to make sure the new and old routers can pass the traffic properly between the two networks.

Does that make sense and if so does it seem possible?

Thanks in advance.  All replies rated.

[milan.kulik · Accepted solution]

Hi,

well, what you need is advertising the prefixes of the sites migrated to the new provider to the old network and vice versa.

The easiest way is your BGP router(s) peering to both providers in your HQ site.

This way you can control which prefixes are advertised to which provider.

You also need to be careful regarding the AS numbers the providers use in their MPLS networks.

In a case of a clash you might get into a trouble with some prefixes dropped.

Best regards,

Milan