T46G/S Multicast on PC Port Issue

[MiKeDaDoC]

Hi there,

we got a few hundred T46G and T46S in use. We connect them directly to some Cisco 2960x switches, we are using LLDP for Voice VLAN provisioning, use 802.1x as well and connect the computers (one behind one phone only) at the pc port using a diffrent VLAN. This works like a charm.

Now we got a video surveilance Software by Panasonic which will send Multicast stream from the cameras to a few computers behind some T46G/S phones

For the first 5 seconds the Multicast stream works fine, but then it stops. Connecting the Computer direct on the Cisco Switch is working, so my multicast Routing is fine.

My question at this Point would be:
Is there anything like a storm control for multicast or anything that would stop the multicast packets from getting to the PC port after a while on the T46G/S phones? And if so, can it be turned off?

EDIT:
when a computer is directly connected to the switch, the mutlicast group is queried by IGMP v2.
When behind a T46G/S it only manages to query the multicast group by using IGMP v1. Guess that is part of the problem.
Seems like the Yealink phone won't handle/pass IGMP v2 requests right. Can anyone confirm this behaviour? Anyone using Mutlicast traffic on the PC Port off a T46G/S and the underlying service, such as a video recording/camera system is in need of IGMP v2 Support?

Thanks