02-29-2008 06:49 PM - edited 03-05-2019 09:28 PM
Hi,
Have a 6509, sup720. I have a vlan with a multicast stream flooding it. Cannot use IGMP as a few of the switchports are connected to old devices which do not do IGMP, but need to listen to the MC stream. I have a few ports in that same vlan which I really need the multicast stream to not leave. (and I cannot move these devices)
Any easy way to filter out multicast from hitting a port on a vlan saturated with MC traffic?
Thanks!
02-29-2008 09:11 PM
Please see:
http://www.cisco.com/en/US/docs/ios/12_4/ip_mcast/configuration/guide/mcbcigmp.html#wp1046446
HTH,
__
Edison.
02-29-2008 09:19 PM
Edison,
Thank you. I read through it. It seems this solution is for IGMP based multicast. My clients are not using IGMP, they are simply passively listening to a stream broadcasted into the vlan.
While searching around I found: switchport block multicast
I'm going to try this tomorrow at work. Think this will work??
Thanks!
Mark
02-29-2008 09:31 PM
That only blocks unknown multicast, you can apply it but I don't think it will work.
How those clients subscribe to the multicast groups? They send an IGMP join for that, don't they ?
__
Edison.
02-29-2008 09:42 PM
Hi,
These are old devices with ports on the same vlan as the MC transmitter. By spraying MC into the vlan all ports receive it(acts like broadcast). It's a horrible implementation, but these clients are really old and do not support IGMP.
We have some other devices(on the same vlan) whom are also getting the MC traffic and are suffering, and we would like to filter it out.
Thank you for your help!
Mark
02-29-2008 09:48 PM
You are only able to filter IGMP groups on Layer2 interfaces.
There is another option to filter multicast traffic (read multicast boundary) but only works on routed (layer3) interfaces.
I don't understand your application but in order to receive multicast traffic, one must join the group, else it isn't multicast but broadcast traffic.
__
Edison.
03-01-2008 05:18 AM
thanks Edison,
The multicast stream is data shot into the vlan by one device. It floods the vlan, and the non IGMP devices can hear it. No need for IGMP. This stuff is VERY old pre-IGMP. We are exploiting multicast's ability to act as broadcast in this subnet. I just need a way to kill the MC traffic on a couple of the ports on the same vlan...
I'll check into the MC boundary stuff. Thank you!
Mark
03-03-2008 04:40 AM
Hi,
I don't think that the command "switchport block multicast" is supported on the 6500 platform, but "switchport block unicast" will probably have the same effect.
Try it out and let us know how you get on.
HTH
Andrew.
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