Multicast communication on L2 vlan

[Nitish_Gupta]

I have two servers S1 and S2 connected to extreme BD switches Sw1 and Sw2 resp. We want to exchange the heartbeat from S1 to S2 via S1 - SW1 - SW2 - S2 over the multicast range. Both the servers are in same vlan. For accomplishing this if i disable the igmp on that vlan will it start forwarding the multicast traffic.

If any other node connected to that vlan do we need to take that node out of that vlan if they do not want to receive that traffic.

[Henrique]

Hi Nitish, I believe that using default value the setup would work. However it depends on the application requirements. I would recommend you to keep both IGMP and IGMP Snooping enabled and test.

Also, to have the switch acting as a IGMP querier, you have to add an ipaddress to the vlan. This will be needed just in case the application "sleeps" for long time. If that happens, the switch will check if the subscriber is still alive by sending an IGMP packet, avoiding traffic issue.

[Nitish_Gupta]

As of now we have to share the design. So if we keep the default feature so that set up will work?

[StephenW]

Disabling IGMP snooping makes all multicast traffic act like broadcast within that VLAN.

Do the two servers communicate without doing anything to the switches?

[Nitish_Gupta]

Not sure, i have not disable or enabled it yet.

As per one of the documentation from Extreme it states that -

"IGMP Snooping - IGMP snooping is a Layer 2 function of the switch; it does not require multicast routing to be enabled. In IGMP snooping, the Layer 2 switch keeps track of IGMP reports and only forwards multicast traffic to that part of the local network that requires it. IGMP snooping optimizes the use of network bandwidth and prevents multicast traffic from being flooded to parts of the local network that do not need it. The switch does not reduce any IP multicast traffic in the local multicast domain (224.0.0.x). IGMP snooping is enabled by default on all VLANs and VMANs in the switch. If IGMP snooping is disabled on a VLAN or VMAN, all IGMP and IP multicast traffic floods within the VLAN or VMAN. IGMP snooping expects at least one device on every VLAN to periodically generate IGMP query messages. To enable or disable IGMP snooping, use the following command:

enable igmp snooping {forward-mcrouter-only | {vlan} name | with-proxy vr vrname}

disable igmp snooping {forward-mcrouter-only | {vlan} name | with-proxy vrvrname}"

So i am looking for the option if i can do it with this. Or i do not require to do anything from my end.

[StephenW]

Disable igmp Snooping is what your looking for.

Are you sure they wont communicate without disabling this. Most work with IGMP, and IGMP snooping enabled.