Dynamic multicast configuration changes

You must not perform dynamic multicast configuration changes when multicast streams flow in a network. For example, do not change the routing protocol that runs on an interface, or the IP address, or the subnet mask for an interface until multicast traffic ceases.

For such changes, ensure that you temporarily stop all multicast traffic. If the changes are necessary and you have no control over the applications that send multicast data, you can disable the multicast routing protocols before you perform the change. For example, consider disabling multicast routing before making interface address changes. In all cases, these changes result in traffic interruptions because they affect neighbor-state machines and stream-state machines.

In addition, when removing port members of an MLT group you must first disable the ports. Changing the group set without first shutting the ports down can result in high-CPU utilization and processing in a scaled multicast environment due to the necessary hardware reprogramming on the multicast records.