Multicast data can be transmitted to user terminals over an IP bearer network in either dynamic or static multicast mode.
In dynamic multicast mode, a device starts to receive and deliver a multicast group's data after receiving the first Report message for the group. The device stops receiving the multicast group's data after receiving the last Leave message. The dynamic multicast mode has both an advantage and a disadvantage:
In static multicast mode, multicast forwarding entries are configured for each multicast group on a device. A multicast group's data is delivered to a device, regardless of whether users are requesting the data from this device. The static multicast mode has the following advantages and disadvantages:
A Layer 2 multicast forwarding table can be dynamically built using IGMP snooping or be manually configured. Choose the dynamic or static mode based on network quality requirements and demanded service types.
If network bandwidth is sufficient and hosts require multicast data for specific multicast groups from a router port for a long period of time, choose static Layer 2 multicast to implement stable multicast data transmission on a metropolitan area network (MAN) or bearer network. After static Layer 2 multicast is deployed on a device, multicast entries on the device do not age and users attached to the device can stably receive multicast data for specific multicast groups.
Static router ports or member ports are used in static Layer 2 multicast.
Static Layer 2 multicast can be used on VLANs and VPLS networks.