[c-nsp] OSPF per-prefix LFA

[Nick Hilliard]

changing the hello-time should affect failover time in your test
environment.  Did you test this?  e.g. compare 1s/4s vs 10s/40s.

Nick

On 28/05/2015 12:58, Mohammad Khalil wrote:
> Ok , Sorry I misunderstood
> So , I think combining both BFD and LFA will do the required failover time
> But why changing the hello-time on both interfaces (the link between R1 and
> R2) will not affect ?
> 
> BR,
> Mohammad
> 
>> Date: Thu, 28 May 2015 12:53:35 +0100
>> From: nick at foobar.org
>> To: eng_mssk at hotmail.com; cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] OSPF per-prefix LFA
>>
>> This has nothing to do with OSPF virtual links. I'm talking about the
>> virtual ethernet interfaces defined in your virtual lab.
>>
>> You can test out whether it's doing what I suggested by changing the
>> hellotime value on the relevant interfaces.
>>
>> Nick
>>
>> On 28/05/2015 12:50, Mohammad Khalil wrote:
>> > Hi Nick and thanks for the reply
>> > All my routers are participating in area 0 , no virtual-link in place
>> > I shutdown the interface connected to R2 (from CSR or R1 side)
>> >
>> > BR,
>> > Mohammad
>> >
>> >> Date: Thu, 28 May 2015 12:36:50 +0100
>> >> From: nick at foobar.org
>> >> To: eng_mssk at hotmail.com; cisco-nsp at puck.nether.net
>> >> Subject: Re: [c-nsp] OSPF per-prefix LFA
>> >>
>> >> On 28/05/2015 12:24, Mohammad Khalil wrote:
>> >> > When I shutdown the interface with R2 (as I do not want to turn off the
>> >> > remote interface on R2 as I cannot turn on BFD on GNS3) and I have
>> >> > checked the route to 2.2.2.2 , it took about 5-6 seconds to install the
>> >> > same route via the backup path (via R3)
>> >>
>> >> did you try this by shutting down both sides of the virtual link at the
>> >> same time? The remote side will not detect carrier loss on a virtual link,
>> >> so ospf failover will be detected by according to the ospf deadtime.
>> >>
>> >> If you handle this with bfd, the failover time should be much faster. Last
>> >> time I measured this (me3600/100ms bfd), the failover time for l2vpn lsp
>> >> rerouting was reliably less than 400ms. I.e. the failover for regular ip
>> >> service should be a little less.
>> >>
>> >> Nick
>>