Why do I see a metric of 20 when I do a show ip bgp neighbor x.x.x.x advertiesed routes when no metric has been set?

[n-russell-biggie]

Hi,

We have 2 edge routers. Both connect to multiple upstream providers and use EBGP. They use IBGP between them.

When doing a show ip bgp neighbor x.x.x.x advertised routes we are seeing all the advertised routes with a metric of 20 on one router and a metric of 0 on the other router.

We have not set the med on either router. The networks are locally sourced using the network command and the aggregare address command in the bgp process.

Any ideas on why I am seeing a metric of 20 on one router and a metric of 0 on the other would be very helpful.

Thanks

[milan.kulik]

Hi,

probably an IGP metric copied to the MED value by default?

HTH,

Milan

[n-russell-biggie]

This is what I thought but I cant see anything that points to that.

However, our IGP is ospf so the metric of 20 seems apt.

[milan.kulik · Accepted solution]

Hi,

compare sh ip bgp ... for some subnet and sh ip route... for the same subnet on the same router.

You should be able to see if the IGP metric is used.

BR,

Milan

[n-russell-biggie]

Hi Milan,

Many thanks for your comments.

We now know why this is the case. On the router that is showing the metrics as 0 we have static routes for the networs in question pointing to null0.

On the router that is showing a metric of 20 we do not have the static routes. The router is learning these via ospf from the first router so I guess this must be the answer.

Thanks again.