Method and apparatus for operation, protection, and restoration of heterogeneous optical communication networks

An optical switching device comprising:

• a set of first network ports for optically connecting the optical switching device to a first bi-directional network link;
• a set of second network ports for optically connecting the optical switching device to a second bi-directional network link;
• a set of first terminal equipment ports for optically connecting the optical switching device to a first portion of terminal equipment;
• a set of second terminal equipment ports for optically connecting the optical switching device to a second portion of the terminal equipment;
• and
• switching elements connected to the sets of first and second network ports and the sets of first and second terminal equipment ports, the switching elements being operable to perform switching for an optical network that utilizes bi-directional network links to optically connect heterogeneous nodes, wherein
• at least one of the heterogeneous nodes is capable of sending and receiving multi-wavelength signals, and at least one of the heterogeneous nodes is incapable of sending and receiving multi-wavelength signals, and
• the performed switching includes at least one of span, ring, and protection transit switching.