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New Member

Multicast on switches


I have a situation like this:

1x Core 6513 Switch.

4x 3550-12T Switches.

All 3550 switches are connected to the 6513 core switch, with one connection each (1Gbps).

Now I need to transfer multicast and unicast between the switches.
I'm sending internet from 6513 to the other switches on vlan100, and using local network at vlan200, also having some other vlans with switches 2960. and my multicast vlan is 222.

on the core i have:
ip multicast-routing
no ip igmp snooping

interface Vlan222
 description MULTICAST
 ip address
 no ip igmp snooping

and on the Ge interfaces i have trunk mode to other switches.
on the switches 3550:
ip multicast-routing
no ip igmp snooping
!interface Vlan222
 description MULTICAST
 ip address
interface gig 0/1
trunk vlan 222,100,300

Multicast and unicast are working on all switches, but the cpu on core is 80% for some reason, when i turn the ip igmp snooping on the cpu goes down to 1% and i lose the multicast only. 
Also when i do ip pim sparse mode on the vlan cpu goes to 99%.

Is there a way to that and make it work normally with low cpu?



Everyone's tags (1)
New Member

Turn IGMP snooping on, on all

Turn IGMP snooping on, on all switches.

Make sure the add each VLAN to the snooping list.


On the core, enable pim sparse-dense mode on each VLAN you want multicast routing to work between.


This is how I route multicast on my network.

New Member

Thank you for your reply.I

Thank you for your reply.

I just tried that, so i get the multicast to work, but my core switch CPU goes to 99%.

Then i removed the ip pim-sparse-dense mode from the vlans, and turn ip igmp snooping on, and the cpu goes to 1% and the multicast works. but i suppose that mcast routing don't work now, i just recieved all mcast at all switches.




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