Multicast Group

[kevin.hu]

I am really confused about multicast group concept. Is it something we need to configure on the router/switch or it is an arbitary group automatically created by the router?

Let's say I have two stream servers, do I need to assign them a Class D IP? If so, how does a receiver distinquish one server from another? Is it because there will be two different groups for each server or because of the different IP?

Thanks in advance,

[rais]

Multicast group is a group of hosts that are communicating with each other using multicast. IGMP is the protocol that makes this grouping possible.

You dont assign class D IPs, however, your computer might be using one as it is a member of that particular group. If you have two mulicast applications running on your network, they will have different class D address.

A very simple example is OSPF. You dont assign your OSPF router address 224.0.0.5. But still it (application on your router) uses it and communicates with other OSPF peers via this address.

Hope this helps.