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

An optical network comprising,

• a plurality of N nodes where N>2, each given node including an optical network interface for coupling to two other nodes in the network and a terminal interface for coupling to terminal equipment associated with the given node, and
• a plurality of N bidirectional optical links connecting the plurality of N nodes in a ring topology to provide bidirectional communication between adjacent pairs of nodes on the network, each adjacent pair of nodes being connected by an intervening one of the optical links, the ring being considered to define two opposite directions arbitrarily designated upstream and downstream so that each node has upstream and downstream adjacent nodes,
• wherein:
• each optical link has a bidirectional working link and a bidirectional protection link;
• each node's network interface includes a first working port, a second working port, a first protection port, and a second protection port;
• each node's first working and protection ports are coupled to the node's upstream adjacent node's second working and protection ports, respectively;
• at least the first working link is configured for multi-wavelength operation;
• the first and second nodes have terminal interfaces providing wavelength division multiplexing capability to support multi-wavelength operation on the first working link;
• all the protection links are configured for multi-wavelength operation;
• each node includes at least one optical switching element to selectively couple that node's first and second protection ports to a bypass path that bypasses that node's terminal interface, thereby allowing multi-wavelength communication between the first and second nodes over the protection links other than the first protection link in the event that the first working and protection links become incapable of supporting multi-wavelength communication between the first and second nodes;
• and
• each node includes control electronics operating to (a) generate messages for output on that node's optical network interface, (b) process incoming messages received at that node's optical network interface, and (c) control that node's at least one optical switching element based on the messages received and the messages expected but not received.

An optical switching node for use at nodes in an optical network, the network including terminal equipment connected by network links,

• the optical switching node comprising:
• first and second sets of bidirectional working and protection network ports for coupling to respective first and second bidirectional network links;
• first and second sets of bidirectional working and protection terminal equipment ports for coupling to first and second portions of terminal equipment, each set of terminal equipment for sending and receiving data to and from said first and second bidirectional network links;
• a set of switch elements connected to said sets of network and terminal equipment ports for establishing span and ring switching in the event of a failure in the network;
• and
• control electronics operating to (a) generate messages for output;
• (b) process incoming messages;
• and (c) control the set of switch elements based on the messages received and the messages expected but not received.

An optical switching node for use at nodes in a network, the network including terminal equipment connected by network links, the network links including

• at least one multi-wavelength link between a pair of nodes having terminal equipment capable of terminating multi-wavelength communications,
• the optical switching node comprising:
• first and second sets of bidirectional working and protection network ports for coupling to respective first and second bidirectional network links;
• first and second sets of bidirectional working and protection terminal equipment ports for coupling to first and second portions of terminal equipment, each set of terminal equipment for sending and receiving data to and from said first and second bidirectional network links;
• a set of switch elements connected to said sets of network and terminal equipment ports for establishing span and ring switching in the event of a failure in a multi-wavelength link;
• and
• control electronics operating to (a) generate messages for output on that optical switching node's optical network interface (b) process incoming messages received at that optical switching node's optical network interface and (c) control that optical switching node's set of switching elements based on the messages received and the messages expected but not received.