clear forwarding route

Fri Oct 18 15:40:12 UTC 2013

Hi,

I would like understand the circumstances under which an operator may want
to clear all (or a subset of) the routes programmed in the forwarding table
(FIB).

I believe the command to do this on Cisco is

clear forwarding {ipv4 | ipv6} route {* | prefix} [vrf vrf-name] module
{slot| all}

I ask this since doing this would result in the router dropping all transit
traffic till the routes get reprogrammed in the FIB.

Why would somebody ever want to do this? One scenario that i can think of
is when because of a bug a route does not get programmed in the FIB and the
operator uses this command to install this once again the FIB.

Thanks, Manav