Multicast configuration...

[jlazzaro]

Setting up multicast for streaming video, however I'm running into some issues. Setup:

Host --- L2 Switch --- Router --- L2 Switch --- Mcast Server

Router has ip multicast-routing enabled, igmp is enabled by default, ip pim sparse-dense-mode is setup on all the virtual interfaces. All the layer 2 switches have igmp enabled as well. Using Windows Media Services with multicast on the server.

There is so much reading on multicast and igmp...just not sure which are optional and which are required to get things working. Can someone comment or help point me in the right direction?

 

[nweaver]

what issues?

 

[spidey07]

What model of switches?

Do you have a mroute for your destination multicast address?

The only things really required for multicast are the following:

multicast routing protocol properly configured on all routers in the path, need RP for PIM-sparse (which is what you should be using, avoid dense)

IGMP enabled on all router interfaces that have receivers

IGMP snooping on all switches with receivers. If they are older switches you'll have to do some other things because they don't support IGMP snooping.

helpful commands:
show ip mroute
show ip igmp
mstat
mtrace

also, try to use private multicast address ranges - 239.x.x.x. Stay away from using 224.0.0.x as a lot of control protocols use this range.

 

[jlazzaro]

Its like a baskin robins over here, we have almost every flavor ;( Cisco 3750 and HP 2800 for the main closets that have been upgraded...older 3Com/Alcatel switches in the closets that have yet to be upgraded.

It was working for a little while, but I'm assuming that was because it was in sparse/dense mode and was probobly flooding everything with the traffic. Since then I have put it in just sparse and have not recieved the stream. This is probobly due to the RP not being set. Should the RP just be set with ip pim rp-address followed by the routers ip?

 

[spidey07]

you setup the RP on a router and then you tell other routers who the RP is. Or you can use auto-RP.

http://www.cisco.com/en/US/tech/tk828/t...logies_tech_note09186a0080094821.shtml

I can see the difficulty with that kind of environment. Maybe you can try it simplified. I assume receivers on the same switch as the server have no trouble receiving it?

You'll have to verify that each switch in the path supports IGMP snooping.

 

[jlazzaro]

Even with the RP configured it still wasnt recieving the stream. So on both the source and target VLAN interfaces (where the mcast source is and where the target that is recieving the steam), I forced them into the multicast group using ip igmp join-group 225.1.1.1 and it worked like a charm. However, does this point to an igmp issue on the L2's? I shouldnt have to force the vlans into the mcast group...

 

[spidey07]

is igmp enabled and pim sparse on the vlan SVIs? (vlan interfaces)

by focing it in the group, that will automatically create a mroute in your multicast routing table.

a trace could certainly help you out here.