When IP Loopback as multicast anchor point

[sugatada9]

When IP Loopback address is configured as IP multicast anchor point? I am configuring a Cisco 4500E series switch.                  

[Jon Marshall]

Not clear on what you are asking.

If you are using PIM sparse mode then you need to configure an RP and Cisco recommend using a loopback IP address for this.

If you are using PIM dense mode there is no need for an RP.

Jon

[sugatada9]

Hi John,

I was checking the config of the old switch before create the new config.  below config was there:

interface looback1

description IP Multicast anchor point

ip address x.x.x.x x.x.x.x

ip pim sparse-dense-mode

Do you think the RP is defined here?

[Jon Marshall]

Sugata

Yes, i suspect that IP is being used as the RP.

If you do a "sh ip pim rp mapping" that should show you the RP address.

Jon