-------- Original Message -------- Subject: Re: [Xorp-users] join messages not sent out (from IGMP to PIM) Date: Thu, 08 Dec 2005 11:38:35 -0800 From: Pavlin Radoslavov <pavlin@icir.org> To: Daniel Sievers <sievers@hilton.rwth-aachen.de> CC: Pavlin Radoslavov <pavlin@icir.org>
There is still another thing I do not understand though:
Our xorp router receives multicast traffic from a cisco 3750 pim-sm enabled router. The cisco will send igmp queries to 224.0.0.1 and xorp will reply for "all-routers.mcast.net" and "pim-routers.mcast.net", but it will never report for the multicast groups joined by clients in the LAN behind the xorp router (,it will show the RPs and igmp groups as joined though in the shell).
So is this the correct behaviour? Should a pim router decide whether it
Yes, this is the correct behavior. The XORP router replies for the all-routes and pim-routers groups because it has joined those two groups.
forwards multicast traffic to another pim router (and not client!) based on pim join status solely, or should xorp always reply to IGMP queries from another pim router by reporting all the groups joined on the client-side LAN?
Yes, in case of PIM-SM routers, the forwarding is based solely on the PIM Join status.
(The reason I'm asking is that the Cisco router will stop forwarding traffic after 5 minutes of running xorp. Crafting an igmp report packet for a particular multicast group will make it forward traffic again for a limited period of time.)
To track the problem, wait until the Cisco router stops forwarding the traffic, and then check the related state: 1. The PIM Join state inside Cisco 2. The PIM Join state inside XORP 3. The IGMP group state inside XORP. Pavlin