[c-nsp] OSPF per-prefix LFA

Nick Hilliard nick at foobar.org
Thu May 28 07:53:35 EDT 2015


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



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