Re: PIM Convergence Problem

makes sense Carlos

John if all else fails clear ip mroute * on the entire path as pointed out, what causes this maybe to do with stale mroute information not being flushed, check to see if you see this prior to doing this

--
BR
Tony
Sent from my iPad
On 21 Apr 2013, at 12:24, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:
> Hmm,
> I may be way off, because it is ages since I played with mcast last
> time, but PIM does not run on top of the IGP/BGP session, it runs along
> and uses the RIB for RPF. If you have pim enabled in the interfaces and
> you tear down the BGP session, PIM does not care. After all, it is
> independent of the routing protocol, isn't it ?
> 
> -Carlos
> 
> John Neiberger @ 20/04/2013 13:49 -0300 dixit:
>> I posted this on cisco-nsp yesterday and didn't get any replies, so I
>> thought I'd run this past the group here.
>> 
>> We ran into an interesting problem last night and I'm a little stumped. It
>> appears that PIM did not follow a unicast routing change after a BGP peer
>> was shutdown. Imagine this simple topology:
>> 
>> [A] ----- [B] ------ [C] -------  [D]
>> |
>> |
>> |
>> [D]
>> 
>> Router A is a CRS and is forwarding PIM joins toward Router D, which is
>> directly attached. We are not running an IGP here. There is only an eBGP
>> session between two ASes that we manage. We shutdown the BGP session
>> between A and D, which caused unicast traffic to switch to the path toward
>> Router B. However, it looks like Router A did not tear down the PIM joins
>> that are now no longer valid. It seems that it was still joining a lot of
>> traffic that it could no longer do anything with since it would now fail
>> RPF checks.
> 
> 
> Rakesh M @ 21/04/2013 08:10 -0300 dixit:
>> Hi,
>> 
>> We had a similar issue with Juniper if my memory goes right. It wont
>> refresh until we manually give a clear command. Did you try clearing Pim ?
>> Would everything get restored if you bring back the link between A and D  ?
>> 
> 
> -- 
> Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net