Re: clear forwarding route

[Joe Abley <jabley () hopcount ca>]

On 2013-10-18, at 11:40, Manav Bhatia <manavbhatia () gmail com> wrote:

> 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).

Because of bugs which have led to the FIB containing data that doesn't match the RIB, and which is causing customer 
enragement. They don't call it CEF for nothing.

> I believe the command to do this on Cisco is
>
> clear forwarding {ipv4 | ipv6} route {* | prefix} [vrf vrf-name] module
> {slot| all}

Cool. Back when I was chasing packets at 6461 the best we could do was

router(config)# interface blah
router(config-if)# shutdown
router(config-if)# no shutdown

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

Seems likely!

> Why would somebody ever want to do this?

Screaming customer on the phone.


Joe