[Xorp-users] PIM-SM in xorp cvs

[Pavlin Radoslavov]

> Just for the record, one needs PIM in all interfaces where multicast
> packets will flow, why is that technically necessary just for curiosity?

Because this is how the PIM-SM protocol operates. E.g., a multicast
data packet will be forwarded on an interface only if an explicit
Join (PIM-SM or IGMP/MLD) message has been received.

> Now I'm getting lots of this errors just with differents interfaces and
> differents from IP addresses:
> 
> [ 2006/08/22 20:36:07  ERROR xorp_pimsm4:30195 PIM +2623 xrl_pim_node.cc mfea_client_send_protocol_message_cb ] Cannot send a protocol message: 102 Command failed Cannot send PIMSM_4 protocol message from 10.0.2.1 to 200.0.204.169 on vif eth4: sendmsg(proto 103 size 28 from 10.0.2.1 to 200.0.204.169 on vif eth4) failed: Operation not permitted
> 
> If you see the 200.0.204.169 router is in eth6, why XORP try to send
> from 10.0.2.1 to 200.0.204.169 on eth4? that obviously will fail and
> probably is why is not permitted, maybe is the source of the other
> problem when I see bogus from IP addresses in PIM-register messages.

If 200.0.204.169 is directly connected to eth6, then eth6 should
have been used to transmit the message.
The above information is not sufficient to answer why eth4 is used
instead. The first thing to check is the MRIB entries, and whether
PIM-SM is actually running on the 200.0.204.169 interface.

> It should send to 200.0.204.169 using the primary IP in eth6 which is
> the interface towards the RP as we have talked previously.
> 
> 989.877636 168.234.203.126 -> 200.0.204.169 PIMv2 Register
> 989.941391 200.0.204.169 -> 168.234.203.126 PIMv2 Register-stop
> 1576.736525 168.234.203.5 -> 200.0.204.169 PIMv2 Register
> 1576.800376 200.0.204.169 -> 168.234.203.5 PIMv2 Register-stop
> 
> What Register-stop packets means?

The Register-stop packet is sent by the RP to the DR and indicates
that the RP is not interested in receiving PIM Register messages for
a particular source and group address.
E.g., typically it is sent when there are no (*,G) receivers.

> And as you can see there are two different IP sources for PIM Register
> packets, that is the problem I mentioned above about bogus sources.

The source addresses seem fine: the PIM Register is sent from the DR
to the RP, and the PIM Register-Stop is sent from the RP to the DR.
Hence, I don't think there is a problem here.

Pavlin