[Xorp-users] Endless PIMv2 Register messages

[Garry Peirce]

It seems you have 3 routers in mesh (?) with all acting as BSRs for the
entire mcast block.
You may have an RP-RPF/DR issue given that.
I'll assume that .3 is likely the DR (highest IP) and perhaps the basis for
your symptom.

First hop (20.1) unicast encapsulates to .2
Join from .2 is ignored by .1 as .3 is the DR (as all are RPs covering the
same group).
.3 creates state but it would not be seen by .1 (which would then initiate
the reg-stop.)
Therefore join/reg-stop never occurs from .2 and .1 continues to send via
encaps-unicast.

1) Can you post 'sh ip pim int' for each of them?

2) Do you need all routers to be RPs? You might select just one to simply
this.
PIM-SM will eventually create SPTs for efficient traffic flow.

3) Also, I noticed this from your initial config (is this from 20.1?)
static {
         disable: false
         route 192.168.51.0/24 {
             next-hop: 192.168.20.2
             metric: 1
         }
         mrib-route 192.168.51.0/24 {
             next-hop: 192.168.20.2
             metric: 1
         }
...


And later (from 20.1 output)

DestPrefix         NextHopRouter   VifName VifIndex MetricPref Metric
192.168.20.0/24    192.168.20.1    rtrs    1                 0      0
192.168.51.0/24    192.168.51.254  eth0.501 0                 0      0


This would seem to show that 192.168.51.0/24 is known via both eth0.501
along with an 
static mrib route to it via 20.2. Perhaps this static mroute is
misconfigured?




> -----Original Message-----
> From: Jeff Mitchell [mailto:jmitchell at ll.mit.edu]
> Sent: Monday, June 28, 2010 4:10 PM
> To: Garry Peirce
> Cc: xorp-users at xorp.org
> Subject: Re: [Xorp-users] Endless PIMv2 Register messages
> 
> On 06/28/2010 04:06 PM, Garry Peirce wrote:
> > Jeff,
> > It wouldn't be the host doing this, but the DR router (in this case
> the XORP
> > router), encapsulating the packets (within PIM control msgs) towards
> what it
> > believes is the RP for this group.
> 
> Ah, thanks for the clarification.
> 
> > Who does XORP think the RP for 234.5.6.8 is?
> > What do 'show pim neighbors' and 'show pim rps' and 'show pim mrib'
> look
> > like?
> 
> Here are the results of running those commands from 192.168.20.1.
> 
> show pim neighbors:
> 
> rtrs                  1 192.168.20.2    2 Sparse      105      86
> rtrs                  1 192.168.20.3    2 Sparse      105      93
> 
> (rtrs is the interface; those are the correct IPs for the two other
> XORP
> boxes)
> 
> show pim rps:
> 
> RP              Type      Pri Holdtime Timeout ActiveGroups GroupPrefix
> 
> 192.168.20.3    bootstrap   1      150     139            0 224.0.0.0/4
> 
> 192.168.20.1    bootstrap   1      150     139            0 224.0.0.0/4
> 
> 192.168.20.2    bootstrap   1      150     139            0 224.0.0.0/4
> 
> DestPrefix         NextHopRouter   VifName VifIndex MetricPref Metric
> 192.168.20.0/24    192.168.20.1    rtrs    1                 0      0
> 192.168.51.0/24    192.168.51.254  eth0.501 0                 0      0
> 192.168.52.0/24    192.168.20.2    rtrs    1                 1      1
> 192.168.53.0/24    192.168.20.3    rtrs    1                 1      1
> 
> Those look fine to me.
> 
> FWIW, I'm running Ben Greear's xorp.ct repo (a bit old by now, as it's
> been moved to GitHub) version 7e89cbe2b0e97d2f76f78b9da7fe590543a91764,
> from May 9th.
> 
> --Jeff