I have a UC520 with phones plugged directly into it, using the latest 8.0.2zip software. I have cisco 7940 and 7945 phones plugged straight into the UC520 switch unit.
Have configured igmp snooping both globally and on vlan 1 and 100, and enabled pim routing. When I put a phone on hold, SH IGMP GROUP shows the multicast group nicely but SH IGMP SNOOPING GROUPS is always blank. I have enabled MOH multicasting and of course ip multicast-routing.
Yet the switch ports on the UC520 are constantly flooded with the MOH multicast. I read elsewhere that the phones are not capable of sending IGMP query reports so flooding the switch constantly is the only way it can work. Could someone confirm whether this Is this the case?