Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

IP Multicasting

I've read through many of the IP Multicasting issues but still can't get mine resolved so I thought I'd give this one more shot.

We have two VLANs on our network (data - VLAN 1, and voice VLAN 23). The core switch is a 4510 and the IDFs are 3560's. I have configured IP MultiCasting on the 4510 and the 3560 I am testing with. VLAN 1 data vlan is subnet and voice (vlan 23) is We have our call manager set up on and our phones all register and work correctly. Have a helper address set up ont he core switch. I have set up each vlan on the core and the 3560 as follows:

interface Vlan1

ip address

ip pim sparse-dense-mode


interface Vlan23

ip address

ip helper-address

ip pim sparse-dense-mode

I have also tried different modes for IP PIM but no success.

This is for a berbee (informacast) paging system that requires multicast. Any assistance would be very much appreciated.



Re: IP Multicasting

I can tell you that Multicast is disabled by default on the 4500. Turn it on with "ip multicast-routing"

Also try these commands to troubleshoot.

"show ip multicast"

"show ip multicast interface"

"show ip pim interface"

"show ip pim neighbor"

"show ip igmp groups"


Re: IP Multicasting

Also, what are you trying to achieve?

CreatePlease to create content