Multicast design...

[mo shea]

Hi...

We have 60 vlans in our network. We use 6509 as a core switch and all edge switches are connected directly to it.

We would be receiving a vidoeconferencing software in 3 months time where 60 out of 2000 employees will be using it.

- What is recommended for such a situation. Shall I create a vlan for those 60 users and enable multicast only there hence I might end up with a campus wide multicast vlan (then I have to worry about ACLs that apply to these users in their original vlans).

OR

- Is it possible to enable multicast on all vlans and limit multicast to specific ports in that vlan?

We are using sup720 (IOS). If possible please provide me with links or configuration examples.

Thanx

[scottmac]

Using PIM-Sparse would allow you to supply the multicast to the entire network, but only to the users that are participating.

The general scheme would be to create a Rendezvous Point (RP) near the source, enable IGMP (I believe v4 is the highest rev today, use it if the endpoint clients can support it), enable CGMP on the switches, and Multicast Routing on the routers.

You must define PIM-Sparse on all the routers and tell them where the RP is (by address).

PIM and IGRP will prune the multicast traffic back to the clients that want to receive it, and the network elements in the path.

CGMP will allow the switches to peek into the upstream routers group tables so they can prune the traffic to the active switchports.

Link to multicast IGMP/CGMP:

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00800b0871.shtml

Link to general Multicast Q&A:

http://www.cisco.com/en/US/tech/tk828/technologies_q_and_a_item09186a00801bb25d.shtml

Link to "Configuring Multicast Routing (IOS 12.x):

http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800d6b79.html

Good Luck

Scott

[b-watkins]

One correction here: If you're using PIMv2, then you needn't configure the RP address on all the routers. You only need to define the RP on the router with a connected interface, and then make sure that you have PIM enabled on all the relevant interfaces.