prevent flood multicast

[JM0945]

Hello,
We deploy comware 5130 (JG936A) switches on our IT equipment.
In some vlan I see multicast flows on the ports of the switches.
Do you know a command that can manage this flow? In the sense of removing unnecessary flow and not flooding the network with this polluting traffic.
Do I have to activate igmp snooping in each vlan?
Are there other commands I can use?
Thank you for your answers.
Sincerely

[Ivan_B]

Hello!

You need to implement IGMP snooping with drop unknown multicast streams. Check in the IP Multicast Configuration guide for details, but in overall you need:

- Enable IGMP snooping querier (if there is no IGMP querier in the VLAN) on the device, closest to the multicast source
- Enable IGMP snooping on all switches between multicast source and listeners
- Set statically multicast Router ports on all switches to point to the multicast source
- Enable " igmp-snooping drop-unknown" feature, as by default IGMP snooping will regulate only known streams, e.g. groups for which it saw a pair of IGMP query-IGMP report. 

Hope it helps!

[JM0945]

Thank you for your answers.
However, is it really useful to activate IGMP snooping querier in all vlans where I find polluting multicast streams?
I wanted to configure the switches and per vlan like this:

#
[vlan 2]
name X
igmp-snooping enable
igmp-snooping drop-unknown
#
[vlan 3]
name Y
igmp-snooping enable
igmp-snooping drop-unknown
#
[vlan 4]
name Z
igmp-snooping enable
igmp-snooping drop-unknown
#

In general, the active elements (computers, printers,...) send multicast streams permanently without targeting a recipient.
The switch must be able to suppress the unnecessary flow.

Thank you for your answers.

Sincerely.

[Ivan_B · Accepted solution]

Hello!

The IGMP querier (in your case it will be IGMP snooping querier since you don't have multicast routing in this case) is the crucial part - without periodical queries IGMP snooping process won't be able to map multicast groups to active receivers. So, in your case configuration should be:

#
igmp-snooping
#
[vlan 2]
name X
igmp-snooping enable
igmp-snooping drop-unknown
igmp-snooping querier
#
[vlan 3]
name Y
igmp-snooping enable
igmp-snooping drop-unknown
igmp-snooping querier
#
[vlan 4]
name Z
igmp-snooping enable
igmp-snooping drop-unknown
igmp-snooping querier
#

Another useful feature to consider is multicast source port filtering:

"This feature enables the Layer 2 device to discard all multicast data packets and to accept multicast
protocol packets. You can enable this feature on ports that connect only to multicast receivers."

system-view
igmp-snooping
  source-deny port <interface-list>

Thus, you can prevent printers, computers and other hosts from sending multicast data. However, be careful with that, as many protocols that have some kind of network neighbors discovery can stop working properly. So, it's a double-edged sword, be careful with it