BGP default-metric

pkhatri · ‎01-16-2005

Hi all,

I'm observing the following behaviour when using the 'default-metric' command under a BGP process:

* 'default-metric 300' is configured

- if 'redistribute connected' is configured, all directly connected routes end up with a MED of 0.

- if 'redistribute static' is configured, all statically configured routes end up with a MED of 300.

- routes redistributed from other routing protocols are also set to a MED of 300

- routes injected by using the network command get a MED of 0 if they are directly connected and a MED of 300 if the route is statically configured or learned from an IGP.

* if NO 'default-metric xxx' is configured

- if 'redistribute connected' is configured, all directly connected routes end up with a MED of 0.

- if 'redistribute static' is configured, all statically configured routes end up with a MED of 0.

- routes redistributed from other routing protocols get advertised with a MED equal to the IBGP metric.

- routes injected by using the network command get a MED of 0 if they are directly connected or statically configured and a MED equal to the IGP metric if the route is learned from an IGP.

Ok, my question is, is this the expected behaviour ?

TIA,

Paresh.

Richard Burts · ‎01-16-2005

Paresh

Yes this is the expected behavior. BGP is different than other routing protocols in its treatment of default-metric. The IGPs use default-metric directly to specify the metric of redistributed routes. The route selection process in BGP is different (and more complex) and does not have a single "metric" that it uses to choose the best route to use.

HTH

Rick

HTH

Rick