Default-metric in EIGRP

[Kevin Melton]

As I am preparing to recertify my CCNP, and am preparing for the route exam, a question came up.

IF a routing protocol, for example OSPF, is redistributed into EIGRP, the metric is defined after "redistribute ospf <process ID>" is configured in the EIGRP AS.

But there is also a "default-metric" command.

Can someone explain why both exist as configurable options in EIGRP?

Thank You.

[Peter Paluch · Accepted solution]

Hi Kevin,

It is purely a matter of comfort. You can define the metric for redistributed in three places:

1. In the route-map used in the redistribute command, if you are limiting the retaken prefixes using a route-map
2. In the redistribute command itself
3. In the default-metric command

When redistributing a route, the router tries to find the appropriate metric to assign in the above ordering - so if you have specified an explicit metric in an applicable route-map block, this will be assigned to the route. If the metric is not specified in the route-map, then the metric specified in the redistribute command will be used, and if that is not configured, either, then finally the default-metric command is used. If not even that one is configured, the route may not be redistributed into EIGRP - be cautious about that. (To be very precise, for static, connected and EIGRP-learned routes, the metric will be retaken from either the outgoing interface or from the original metrics; however, if routes from another routing protocol are retaken, the metric must be specified explicitly.)

Especially when doing a quick-and-dirty redistribution from multiple sources into EIGRP (like, static, connected, OSPF, RIP, ...), it may actually be more convenient to define the redistribution metric just once in the default-metric command, rather than specifying it repeatedly in redistribute statements.

But other than that, there's no much difference.

Best regards,
Peter

[Kevin Melton]

Peter

Thanks for such a detailed yet easy to understand answer.  Kudos!

[paul driver]

Hello Kevin

I agree  100%

[paul driver]

Heloo
Eigrp routes are calculated upon these metric msot important Bw/Delay used for best path calcualtion

The default metric (weights) is a catch all - meaning the value you specify here is the default for the entire eigrp routing process

Ospf routes redistributed into eigrp specified with a specific metric will inherit those values upon redistribution.

Editied...

Peter beat me to it

res

Paul

[Kevin Melton]

Paul

I do like your answer "The default metric (weights) is a catch all - meaning the value you specify here is the default for the entire eigrp routing process".

Catch-all is the takeaway here.

thanks for your response.