Symptom:
Multicast traffic is limited on 69xx.  
The multicast traffic is going from the 69xx network port to a PC connected on the PC port, same phone.
The speed for the multicast transmission decreases a lot when the phone is in between
if there is no phone connected, the transmission speed for multicast traffic is about 10 -12 MB
When the phone is there, the speed reduces to 2MB

Conditions:
69xx  processing multicast traffic and passing them to the PC port
firmware 9.3.3