Comparing IGMP and MLD
One of the main aspects of multicast routing is managing the network devices that receive the multicast. The key abstraction in multicasting is the multicast group: a given multicast stream is associated with a group, which is identified by a specific multicast IP address. Group members receive the multicast stream; nonmembers do not.
In IPv4 networks, multicast group membership is managed by using IGMP. In IPv6, the corresponding protocol for managing group membership is MLD. For more information on multicast routing fundamentals and Protocol Independent Multicast (PIM), refer to Ciena Vyatta Network OS Multicast Routing Configuration Guide and .