[c-nsp] BFD and EoMPLS

[Jason Lixfeld]

On 2010-12-22, at 5:08 AM, Michael Robson wrote:

<snip>

> If I configure BFD for each link and also attach it to OSPF and repeat the experiment, the time to re-route is still 6-7 seconds.
> 
> I can reason that this might work or that it shouldn't: does this not work because there is no direct hook between BFD and LDP or should it work because the pseudowire terminating loopbacks are advertised in OSPF, OSPF has been hooked into BFD and ultimately the LFIB is built via the FIB and LIB (or perhaps with this testbed because the size of the network and Penultimate Hop Popping it means that the FIB is used anyway)?

</snip>

With regards to LDP, what about enabling mpls ldp session protection if you find that you really need it?  (http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/fssespro.html)

With regards to the OSPF/BFD integration, I'm not sure if it's the same for ISIS but I recently went through an exercise with BFD/ISIS integration where I was getting less than desirable results on a link failure while BFD tuned way down.  Turned out that regardless of how quickly BFD reacted, I still had to tune down the ISIS timers to react more quickly when BFD detected a link failure.

Now then, when I was testing this, I was using some pretty scary numbers, but ultimately got this to work in a lab, flawlessly.  The result was that I went from 6-7 seconds worth of packet loss to zero seconds of packet loss between CEs when I yanked a link between two P/PE routers.  Note that while I was able to achieve these results, I did so without ldp session protection enabled (I just recently read about it, but haven't had a chance to try it) and using L3VPNs, not EoMPLS.  Also, this was done between 7301s, not 6500s, so YMMV on both counts:

Here's what my end looked like:

!R1
!
interface GigabitEthernet0/0
 mpls ip
 bfd interval 50 min_rx 50 multiplier 3
 isis bfd
!
interface GigabitEthernet0/1
 mpls ip
 bfd interval 50 min_rx 50 multiplier 3
 isis bfd
!
router isis
 spf-interval 5 1 50
 prc-interval 5 1 50
 lsp-gen-interval 5 1 50
!

!R2
!
interface GigabitEthernet0/0
 mpls ip
 bfd interval 50 min_rx 50 multiplier 3
 isis bfd
!
interface GigabitEthernet0/1
 mpls ip
 bfd interval 50 min_rx 50 multiplier 3
 isis bfd
!
router isis
 spf-interval 5 1 50
 prc-interval 5 1 50
 lsp-gen-interval 5 1 50
!

P.S. While digging through the archives for content, I also found this, which may be of more help to your particular configuration:

!
router ospf 1
 timers throttle spf 10 100 5000
 timers throttle lsa all 10 100 5000
 timers lsa arrival 80
!