Some network switches or firewalls may have certain packet filtering features which can prevent network traffic, including multicast packets. Please ensure that features such as IGMP V2 snooping are enabled.
The address space used for our multicast transmission is 230.0.0.0 – 239.255.255.255.
It is recommended that wherever possible the teacher and students for a classroom are connected to the same network switch in order to optimise both audio and screen data transfers. If this is not the case then the separate switches may need their configuration changed to allow multicast transmissions between them for the above address space.
[...] just enabling it is not enought you have to configure it. I have also found this on the sanako site What are the multicast requirements for Study? | Sanako UK Blog Has anyone any ideas how to configure this in a cisco sg200-50 gigabit smart switch Richard [...]
In the vast majority of switches enabling the IGMP Snooping setting is enough due to the fact that they have an in-built learning mode that basically monitors the IP multicast traffic and adds routing information as it goes along. However, some of the more sophisticated Level 3 switches have to have the multicast address ranges added and tied to the correct VLAN etc… there are also some that will have a threshold limit for allowed multicast traffic. Our history shows that over 95% of installations of Study to date (and this is from a database of many thousands of installations all over the world) only require IGMP snooping to be enabled but perhaps this is an area that will change as the switch architecture and security settings develop. Thank you for your post and we will take steps to investigate this issue to see if we can be more explicit in future.
Good to know that all is now sorted at your site.