igmp / pim - multicast

carl_townshend · ‎05-30-2008

Hi All, what are the major components of setting up multicast, do I use igmp or pim ? or both ?

and what do I need in my network, also how do I route multicast ?

n.nandrekar · ‎05-30-2008

hi!

For a multicast network, you need both Igmp as well as a multicast routing protocol ( PIM/DVMRP etc.)

The routing protocol works between the routers to send the multicast stream from the source router to the end router. This is the work of PIM ( note that PIM requires any unicast igp for its working).

Igmp comes into play for the leafs where it actually conducts the information of the host's intntions to join a multicast stream to the end router.

So in summary, PIM works in the core while igmp at the leafs.

The following link will give you more details on the matter :

www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.1/19ew/configuration/guide/mcastmls.pdf

Cheers!

Niranjan.