Static routes metric

[joyride_us]

Hi,

If you have 2 static routes on the same router pointing to the same host with 2 different metrics. I redistribute those routes to my central site through EIGRP (for example). I guess the lowest metric route will be used by the central site. What happens if this static route (with the lowest metric) does not work any more (network failure on that path) ?

Thank you

[Kevin Dorrell · Accepted solution]

We need to distinguish between Administrative Distance and metric here. If you define a floating static route, the number just after the route is the Administrative Distance. That is lost and becomes 170 when you redistribute into EIGRP. That is, if you have an EIGRP internal route (AD=90) for the same prefix, it will mask the redistributed static as far as your EIGRP domain is concerned.

The redistributed versions of the static routes get EIGRP metrics that are determined by the default-metric command under the router eigrp. If you don't specify default metrics, then the static doesn't get redistributed unless its next-hop is an interface, in which case it gets the EIGRP metrics of the interface.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fiprrp_r/1rfeigrp.htm#wp1017526

If you can arrange that the static routes are dependant on the interface, then the redundancy will work correctly even after redistribution. For example, if the better static has next-hop to the other end of a serial line, and that next-hop becomes unavailable, then the static will be purged from the routing table, and the redistributed version with it.

I hope that answers the question. Sorry for the lecture on AD vs. metric. ;-)

Kevin Dorrell

Luxembourg

[joyride_us]

you are very welcome!!