BGP as the PE-CE Protocol

Muhammad Zeeshan Sanaullah · ‎11-08-2009

Hi,

What considerations should be kept in mind when using BGP as the PE-CE Protocol.

I have a simple setup with a Main Site Connecting Regional Offices using MPLS as Primary and DXX (Leased line) as Backup.

I think I can modify the AS-Path to make the MPLS Cloud Primary and DXX as Backup

Any other thing I need to take care of ?

Thanks

Zeeshan

jcozzupoli · ‎11-09-2009

Hi,

There are a few things to consider:

- Exit points out either link from within your network using Local Preference.

- Entry points for return traffic over either link, best to use MED.

- If other sites are also running BGP as their IGP, you'd need to think about using the same ASN or different ASN to them. If you go with same ASN, you'd need to ask the provider to configure "as-override" or you could configure "allowas-in" which forces BGP to allow routes in that contain its own ASN (which is dangerous).

- Also, remember convergence times aren't the quickest with BGP, so you may need to tweak timers such as "bgp graceful-restart" and also, simple keepalive and holdtimers.

There are just a few things I could think of for now, as I don't know the size and complexity of your network.

Cheers,

Joe.

shivlu jain · ‎11-09-2009

Are you going to run BGP with backup?

regards

shivlu jain