System-wide synchronized switch-over of multicast flows

A network device, comprising:

• multiple ports, for communicating over a communication network;
• and
• packet processing circuitry, configured to:
• receive via the ports packets belonging to a plurality of multicast flows;
• receive, for each of the multicast flows, (i) a first configuration that specifies a respective first group of clients that are to receive the multicast flow prior to a specified switch-over time, and (ii) a second configuration that specifies a respective second group of clients that are to receive the multicast flow after the specified switch-over time;
• forward the multicast flows via the ports in accordance with the first configuration;
• extract from a field in at least one of the packets a value that is indicative of the switch-over time;
• and
• based on the extracted value, switch-over forwarding of each of the multicast flows from the respective first group of clients to the respective second group of clients at the switch-over time, simultaneously both (i) for all the clients associated with each multicast flow and (ii) for all the multicast flows forwarded by the network device.