[c-nsp] OSPF per-prefix LFA

[Dan Peachey]

On 28 May 2015 at 13:43, Mohammad Khalil <eng_mssk at hotmail.com> wrote:

> Hi
> Dan , carrier-delay did not do the trick for me
> George , I have configured the below
> router ospf 1
> timers throttle spf 777 888 999
>
> And , yes it made a difference :)
> Now , the question in my mind is that if I changed these timers to lower
> values than the default , will that affect the performance of the router or
> the SPF calculations negatively ?
>
> BR,
> Mohammad
>
>
I guess that makes sense actually. After link down, RIB and FIB entries are
removed then you have to wait for IGP to re-calculate before backup RIB
route becomes best path (separate of FIB, as the backup FIB route was
already programmed).

You should definitely be tuning your SPF timers anyway, I was just looking
at this more from a local link down perspective.

I suspect if you were running traffic through it end to end you would see <
100ms convergence when path switched over as once the dead FIB route is
removed the backup is used straight away regardless of IGP recalculation.

Dan