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

Apparatus for use in an optical ring network where

• each of a plurality of N nodes where N>2 is coupled to a pair of adjacent nodes, designated that node's upstream and downstream adjacent nodes, via optical links designated that node's upstream and downstream optical links,
• each optical link includes a bidirectional working link and a bidirectional protection link, and
• at least a given optical link's bidirectional working link includes separate first and second working fibers, and that optical link's bidirectional protection link includes separate first and second protection fibers,
• the apparatus comprising:
• at least one optical switching element associated with each node to selectively couple that node's upstream and downstream protection links to a bypass path that bypasses terminal equipment at that node;
• and
• control electronics associated with each node operating to (a) generate supervisory messages for output on that node's upstream and downstream optical links, (b) process incoming supervisory messages received at that node's upstream and downstream optical links, and (c) control that node's at least one optical switching element based on the supervisory messages received and the supervisory messages expected but not received;
• the control electronics associated with at least one node coupled to the given optical link generating supervisory messages for output on each of the given optical link's first and second working fibers and on each of the given optical link's first and second working fibers;
• and
• said control electronics associated with said at least one node coupled to the given optical link processing incoming supervisory messages received from each of the given optical link's first and second working fibers and from each of the given optical link's first and second protection fibers.

An optical ring network comprising:

• a plurality of N network nodes, each having associated terminal equipment, where N>2;
• a plurality of N bidirectional optical links, each including a working link and a protection link, said optical links connecting the plurality of N network nodes in a ring topology to provide bidirectional communication between terminal equipment at adjacent pairs of network nodes, each adjacent pair of network 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 network node has upstream and downstream adjacent network nodes connected to that node by upstream and downstream working links and upstream and downstream protection links;
• at least a given link connecting a given pair of nodes having a given working link and a given protection link that are configured for multi-wavelength operation;
• all the remaining protection links being configured for multi-wavelength operation;
• a plurality of N optical switching nodes (OSNs) each associated with a respective network node and being interposed between that network node's terminal equipment and that network node's upstream and downstream optical links, each OSN having an optical network interface for coupling to that network node's upstream and downstream optical links, and a terminal interface for coupling to that network node's terminal equipment;
• and
• WDM couplers at each of said given pair of network nodes, coupled between the terminal equipment at each of those network nodes and the OSN at each of those network nodes, thus permitting bidirectional multi-wavelength communication between said given pair of network nodes;
• each OSN including an optical switching assembly having switch states including a normal state, at least one span switching state, at least one ring switching state, and at least one bypass state;
• each OSN including control electronics operating to (a) generate messages for output on that OSN's optical network interface, (b) process incoming messages received at that OSN's optical network interface, and (c) control that OSN's optical switching assembly based on the messages received and the messages expected but not received;
• each OSN, when in at least one of its bypass states, selectively coupling the associated network node's upstream and downstream protection links to a bypass path that bypasses terminal equipment associated with that network node, thereby allowing multi-wavelength communication between said given pair of network nodes over the protection links other than said given protection link in the event that said given link's working and protection links become incapable of supporting multi-wavelength communication between said given pair of network nodes.

An optical ring network comprising:

• a plurality of N nodes, including first and second nodes, where N>2;
• 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 optical link including a bidirectional working link and a bidirectional protection link, wherein
• a first optical link of the plurality of optical links connects the first and second nodes,
• the working link of the first optical link is configured for multi-wavelength operation, and
• all the protection links are configured for multi-wavelength operation;
• 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 connected to that node by upstream and downstream working and protection links;
• each given node including
• terminal equipment, including an optical network interface, which terminal equipment originates and terminates signals traversing that node's upstream and downstream working and protection links through the optical network interface,
• an optical switching assembly disposed between that node's terminal equipment and that node's upstream and downstream working and protection links, the optical switching assembly having at least one state that selectively couples that node's upstream and downstream protection links to a bypass path that bypasses that node's terminal equipment, thereby allowing multi-wavelength communication between the first and second nodes over the protection links other than the protection link of the first optical link in the event that the working and protection links of the first optical link become incapable of supporting multi-wavelength communication between the first and second nodes, and
• control electronics operating to (a) generate messages for output on that node's upstream and downstream working and protection links, (b) process incoming messages received at that node's upstream and downstream working and protection links, and (c) control that node's optical switching assembly based on the messages received and the messages expected but not received.

An optical network comprising:

• first and second rings sharing a common optical link, referred to as the shared link, the shared link including multi-wavelength working and protection links;
• the first ring having all protection links capable of supporting multi-wavelength operation;
• the first ring including nodes and intervening optical links wherein each node on the first ring includes,
• terminal equipment that generates and receives data transmissions, the terminal equipment having an optical network interface for coupling to that node's upstream and downstream optical links,
• an optical switching assembly disposed between that node's terminal equipment and that node's upstream and downstream optical links, the optical switching assembly having at least one state that selectively couples that node's upstream and downstream protection links to a bypass path that bypasses that node's terminal equipment, thereby allowing multi-wavelength communication between the first and second nodes over the protection links other than the protection link of the first optical link in the event that the working and protection links of the first optical link become incapable of supporting multi-wavelength communication between the first and second nodes, and
• control electronics operating to (a) generate messages for output on that node's upstream and downstream working and protection links, (b) process incoming messages received at that node's upstream and downstream working and protection links, and (c) control that node's optical switching assembly based on the messages received and the messages expected but not received.