How can I tell if my switches are allowing multicast?

[Andrew White]

Hello,

We have a TV system installed at work that has been working fine for 2 years and it basically shows the news channels across different TV screens on the network located across our floor.

The quality has become very choppy recently and it get's it's feed from the Internet.  I've checked the bandwidth during this time and it is low so the company that supports it is popping in, but mentioned it runs on multicast and can I check the following on out data switches:

• Multicast address range 224.0.O.O - 239.255.255.250
• All network switch ports should be set to auto negotiate speed and duplex.
• Ensure no other devices on the switch/network/VLAN are trying to operate on the same multicast addresses.
• IGMP V2 snooping should be enabled across the network.
• IGMP max query response time may need increasing (default is typically 10 seconds).
• Fast leave should be turned off
• Where available PIM sparse mode should be used and multicast groups added to the sparse mode list.

I'm not sure why it has degraded, but how can I check the above.  The TV screens are plugged into a 3650x then trunk to a 2960x where the internet is.  It's all 1GB links, internet is 100/100Mbps.

Thanks

[balaji.bandi]

There are many reasons since it was working suddendly broken, causes some network changes ? or routing changes ?

So until we know more information and configuration how you have configured, hard to say and guide that it was the issue.

best to start with :

https://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/16450-mcastguide0.html

[Andrew White]

We have not changed anything from what we have researched, so we do think it’s the TV equipment. But the want me to double check the multicast settings that’s all.

[balaji.bandi]

On the First instance nothing changed, suggest to restart TV device and check.

[Andrew White]

They all play ok for sometime the degrade.

This is the switch port config for one:

interface GigabitEthernet2/0/33
description AV
switchport access vlan 150
switchport mode access
auto qos trust dscp
spanning-tree portfast
spanning-tree bpduguard enable
service-policy input AutoQos-4.0-Trust-Dscp-Input-Policy
service-policy output AutoQos-4.0-Output-Policy