Steve Bertrand wrote:
My problem is the noticeable delay for switchover when the fibre happens to go down (God forbid).
I would like to know if BGP timer adjustment is the way to adjust this, or if there is a better/different way. It's fair to say that the fibre doesn't 'flap'. Based on operational experience, if there is a problem with the fibre network, it's down for the count.
Thanks to all for the great feedback. In summary, I've learnt: - Even though BFD would be a fantastic solution and would require only minimal changes (to my strict uRPF setup), it's a non-starter, as I don't fit all of the requirements that Ivan pointed out - fast-external-fallover is already enabled by default, but in order for this to be effective, the interface has to physically go into down state. In my case, although not impossible, it is extremely unlikely - adjusting BGP timers is the best option given it's really the only one left. Although I generally try to keep consistency among all equipment (if I set the timers at one end, I would set them the same at the other). Iljitsch recommended to leave the CPE end alone, so if something bad happens, access to the CPE would not be necessary to revert the change - I'm going to set the timers to 5/16. I like the idea of the extra second on top of being divisible by three. That will ensure that at least three keepalives have a chance to make it before the session hold timer is reached Cheers! Steve