[c-nsp] FRR Recovery Time

[Oliver Boehmer (oboehmer)]

gladston at br.ibm.com <> wrote on Sunday, January 15, 2006 9:20 PM:

Hi,

> If you have measured FRR recovery time, did you find consistent times
> between your findings on lab and the 50msec stated on theory?
> We measure it using two tools. However, the results are inconsistent
> with the expected value of 50msec.
> 
> This is the network:
> 
>      RA1--------------------------RB1
>        |                                          |
>        |                                          |
>       RA2-------------------------RB2
> 
>  The main tunnel is RA1-RB2
>  The backup tunnel is RA1-RA2-RB2-RB1

What type of protection do you have configured? Which path does the
RA1->RB2 tunnel take? Or is the tunnel RA1->RB1 and you protect the link
RA1-RB2?

> The links are 155Mbps between RA1-RA2 and RB1-RB2 and Giga between
> RA1-RA2 and RB1-RB2

copy&paste error? Which link is what? can you please re-post your exact
configuration?

Do you have bi-directional tunnels configured, or are you measuring
one-way only (somewhat doubt it using your 2nd measurements with the IP
application).

[...]
> Comparing the results:
> These were the result using the first tool:
> 70msec
> 481msec
> 411msec
> 371msec
 
[...]

> Nevertheless, as it is different from the documentations that states
> 50msec for the operation of FRR, we would like to double check the
> result. We used two ways to fail the link:
>     -disconnect the POS fiber manually
>     -shutdown the POS interface (using the command POS ais-shut)
> As the time using manual shutdown increased to 800msec, we discarded
> the test using this way of failing the link and just use the first
> way, manually disconnecting the fiber.
> 
> Your comments and recommendations are more than welcome.
> 
> I am wondering if there is any timer on Cisco that can be configured,
> as "carrier-delay ms x", to improve FRR time. However, as opposite of
> this command that introduces some delay, I would like to improve the
> time of FRR is possible and test again.

Which routers/interface-cards are you using running which IOS release?
How large is your FRR database, i.e. how many tunnels do you protect? Do
you have tuned your IGP to fast-convergence and how many routes are in
your routing table (IGP + BGP)?
The FRR debug would be interesting..

	oli