MPLS - unknown metric on routes found on BGP table

[CCC4046_2]

Hi All,

Wondering what are below highlighted value as they are used for route preferences.

pe401c6506#sh ip bgp vpnv4 vrf DATA 10.18.0.0/16

BGP routing table entry for 10.254.0.253:120:10.18.0.0/16, version 157413

Paths: (2 available, best #2, table DATA)

  Advertised to update-groups:

     1          2          3          4          5          6          7

     8          10         11         12         13         14         15

     53

  Local, (aggregated by 65001 10.254.4.254), (Received from a RR-client), imported path from 10.254.4.254:120:10.18.0.0/16

    10.254.4.254 (metric 3) from 10.254.4.254 (10.254.4.254)

      Origin IGP, metric 0, localpref 100, weight 300, valid, internal, atomic-aggregate

      Extended Community: RT:65001:120

  Local, (aggregated by 65001 10.254.4.253), (Received from a RR-client), imported path from 10.254.4.253:120:10.18.0.0/16

    10.254.4.253 (metric 2) from 10.254.4.253 (10.254.4.253)

      Origin IGP, metric 0, localpref 100, weight 300, valid, internal, atomic-aggregate, best

      Extended Community: RT:65001:120

*Note - Are red highlighted some sort of different metric from the BGP MED metric?

Regards,

Hin

[Vaibhava Varma · Accepted solution]

Hi Hin

The Red Highlighted Metrics are the IGP Metrics to reach the MP-iBGP Peer which is the 8th Criterion for Best Path Selection Algo..

If we will check for a show ip route 10.254.4.254/253 we will see the IGP metric as to be as the one highlighted in red above.

Hope this helps to answer your query..

Regards

Varma

[Arun Nair]

Hi Vaibhava,

So it it a metric for reaching the next hop, rather than reaching the prefix itself, because 8th Criterion means it is getting  knee-deep into the BGP path selection algo and others are a tie?

Do correct me if I am wrong.

[Vaibhava Varma]

Hi Arun

Yes its the IGP metric to reach the next-hop and would be applicable when the upper 7 best path selection criterions are a tie..

Hope this helps to answer your question..

Regards

Varma

[Arun Nair]

Sure does

[CCC4046_2]

Thanks Varma for the eleboration.