[Xorp-users] Multicast without PIM on internal interface while PIM on external

[Dan Lukes]

Pavlin Radoslavov wrote:
>>	There are no other router within the subnet, so there are no PIM 
>>neighbors on it. No PIM messages should be received nor sent on it. 
>>There are multicast hosts, so multicast packets should be routed to and 
>>from the subnet. Hosts are not allowed to send PIM Register by self.

> As a temporary soultion we could add a PIM-SM configuration switch
> per interface that disables the sending and receiving of all PIM
> packets, but this switch may go away once we have the multicast
> routing policy in place.

> FYI, you cannot prevent the hosts from originating PIM Register
> messages by applying the above solution, because the PIM Register
> messages are directly unicast to the RP. You would either have to

	True, I'm still not familiar with all aspects of PIM.

	The policy related to unicast PIM messages not destined to router must 
be forced by firewall.

> If your RP is a XORP router, you should know that currently we don't

	FYI, it's my upstream ISP's RP. AFAIK it's a Cisco 3600 router running 
IOS 12.1(5) or newer.

>>	I'm almost sure. At the time I seen it there has been no active PIM 
>>routers on any interface (i have statis RP configured in), so NOCACHE 
>>can't be trigered by PIM activity.
> 
> Can you replicate the problem by running a multicast receiver
> (only). I have suspicions that the multicast data packets originated
> by an application that is both a sender and a receiver are the
> trigger for the NOCACHE.

	I'm not sure what configuration I should try.

	Do you request I run a multicast receiver on router ? On a station ? 
With static RP or with current configuration ?

	With current configuration there are still some NOCACHE messages but 
originated from external interface (example is bellow).

	But I'm lost a lot. What's the problem now ? Do you think the kernel 
should not generate NOCACHE message ?

					Dan



  ===============
[ 2005/06/16 01:45:10 TRACE xorp_igmp MLD6IGMP ] RX 
IGMP_V2_MEMBERSHIP_REPORT from 195.113.27.138 to 224.2.127.254 on vif 
vlan666
[ 2005/06/16 01:45:10 TRACE xorp_igmp MLD6IGMP ] JOIN: 195.113.27.138 
joined group 224.2.127.254
[ 2005/06/16 01:45:10 TRACE xorp_pimsm4 PIM ] Add membership for 
(0.0.0.0,224.2.127.254) on vif vlan666
[ 2005/06/16 01:45:10 TRACE xorp_fea MFEA ] RX kernel signal: 
message_type = 1 vif_index = 1 src = 194.160.23.22 dst = 224.2.127.254
[ 2005/06/16 01:45:10 TRACE xorp_pimsm4 PIM ] RX NOCACHE signal from 
MFEA_4: vif_index = 1 src = 194.160.23.22 dst = 224.2.127.254
[ 2005/06/16 01:45:10 TRACE xorp_pimsm4 PIM ] src = 194.160.23.22 is NOT 
directly connected
[ 2005/06/16 01:45:10 TRACE xorp_pimsm4 PIM ] install a MFC in the kernel
[ 2005/06/16 01:45:10 TRACE xorp_pimsm4 PIM ] Add MFC entry: 
(194.160.23.22,224.2.127.254) iif = 1 olist = ..O.
[ 2005/06/16 01:45:11 TRACE xorp_fea MFEA ] RX kernel signal: 
message_type = 1 vif_index = 1 src = 128.40.89.156 dst = 224.2.127.254
[ 2005/06/16 01:45:11 TRACE xorp_pimsm4 PIM ] RX NOCACHE signal from 
MFEA_4: vif_index = 1 src = 128.40.89.156 dst = 224.2.127.254
[ 2005/06/16 01:45:11 TRACE xorp_pimsm4 PIM ] src = 128.40.89.156 is NOT 
directly connected
...