Multicast lightpaths

In the modern era, it is important to protect multicast connections in an optical mesh network.

Recently, multicast applications have gained popularity as they are important to protecting critical sessions against failures such as fiber cuts, hardware faults, and natural disasters.

Multicast applications may include multimedia, medical imaging, digital audio, HDTV, video conferencing, interactive distance learning, and distributed games.

There are two types of switch architectures that are usually used:[2] Multicast lightpaths protection refers to the network's prompt response to reroute traffic onto an alternative path in the event of a failure.

The primary light tree is shown in solid lines and (directed-link-disjoint) the back up light tree is shown in dotted lines carrying traffic from source node to destinations.

This is easy to achieve with one-to-one protection where the dedicated backup path is already provisioned and traffic is simply switched to it on failure.