How to setup up Multicasting on a LAN

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Jun 14th, 2007
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Currently we are trying to setup multicast on a LAN. An application being used allows for building multiple desktops from a server using multicasting. However multicasting isnt setup in the router or switches. so far i have enable multicasting on the router using the global command. What are the next steps. My understanding is i have to enable IGMP on the LAN interface of the router and also CGMP on the switches, is this correct? if so how do i do this. Repeating that multicast only needs to be done on the LAN not across multiple routers.

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Jon Marshall Thu, 06/14/2007 - 22:51
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If you only need to multicast on a single vlan then if your switch supports it you can do the following

1) Turn on IGMP snooping. You will have to do this anyway. "ip igmp snooping".

2) If your switch supports it you can then also make it an "igmp querier".

This would be enough for it to work.

If your switch doesn't support "igmp querier" you need to add under the router interface connected to the LAN

router(config-if)# ip pim dense-mode

Note that you will still need to turn on IGMP snooping on your switch.

If your switch doesn't support IGMP snooping then you should use CGMP.




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