[Xorp-users] PIM-SM in xorp cvs

[Otto Solares]

On Tue, Aug 22, 2006 at 10:08:08PM -0700, Pavlin Radoslavov wrote:
> > 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.

Is this true for SSM model too and for IPv6? Thanks.

> > 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.

PIM-SM is running on all interfaces, as I'm not running BGP in XORP
but in Quagga I'm using the fib2mrib to populate it, I can confirm
that the URIB is ok and the route to 200.0.204.169 is via eth6, dunno
why xorp try to send to 200.0.204.169 via other interfaces, should I
check in another place?

> > 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.

Ok.

> > 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.

I think it is a problem because there are 2 differents source addresses
used by XORP 168.234.203.126 and 168.234.203.5, if I understand
correctly XORP will pick _ONE_ time it's primary address (168.234.203.5)
and and stick to it for talking to the RP.  Other address to talk to the
RP is dubious IMO.

Thanks.

-otto