In a network having working and protection paths, extra traffic is put on the protection paths when they are not being used by working traffic. In the event of a fault in a working path, the working traffic is switched to a respective protection path using a span switch operation. The extra traffic is displaced, but at least some of it is protected by switching it to an alternative path using a ring switch operation.

Data network having enhanced availability of extra traffic

Protection techniques within optical communication networks are extremely important. An alternative to a line protection scheme, as most current optical communication networks use, is to utilize a path protection technique in which working and protection paths that are desired are assigned during network setup. During normal operations, only the working path is configured within the network elements' switch fabric with protection paths being left unconfigured. If a failure indication is detected in the working path by a network element, a protection entry within a routing table of the network element is looked up to determine protection switching data that is required to switch the data traffic to the pre-assigned protection path. This protection switching data is inserted within the path overhead for the data traffic so that it can be communicated to all of the network elements that require their switch fabrics reconfigured to establish the protection path of communications. This protection technique allows for similar switching speed to that of line switching protection such as BLSR designs, but with an increase in efficiency in terms of protection bandwidth.

Apparatus and method for optical communication protection

In a mesh network, a network element for providing protection switching in a 1:N shared mesh protection scheme having a first protection path associated with a pair of working paths selected from the N working paths is disclosed. The network element comprising: (a) a link for connecting the network element to a first working path of the pair of working paths in a path layer of the network, the path layer including a plurality of interconnected network elements; (b) a routing table accessible by the network element, the routing table for having local protection channel information associated with a local protection segment separate from the first protection path, the local protection segment connecting the network element and one of the interconnected network elements adjacent to the network element; and (c) an identification module for using the local protection channel information to identify an available protection channel on the local protection segment in the event of failure of a local working segment of the first working path, the local working segment connecting the network element and said one of the adjacent interconnected network elements; wherein the available local protection channel on the local protection segment is used to switch local network bandwidth from the failed local working segment to the local protection segment after the failure has been detected. Selection functions are also disclosed.

Shared mesh signaling method and apparatus

A method and apparatus for redirecting data communications traffic in a mesh network via an alternate path. When operating in a SONET environment, the method makes use of bi-directional line switching ring (BLSR) principles in addition to a dynamically invoked flexible ring formation mechanism. The network comprises a plurality of computing nodes, where the plurality of computing node are interconnected to one another by a plurality of communication links and exchange traffic with one another over the communication links. The method includes detecting a failure on a certain communication link, the certain communication link interconnecting a first computing node and a second computing node. Upon detecting a failure on the certain communication link, at least one ring protection path is generated between the first computing node and the second computing node, where the ring protection path excludes the certain communication link. A least part of the traffic from the certain communication link is redirected through the ring protection path. The method makes use of the spare transport capacity on the communication links to carry the redirected traffic between the first computing node and the second computing node.

Mesh network protection using dynamic ring

Methods and apparatus for automatically creating a circuit path that includes specified elements are disclosed. According to one aspect of the present embodiment, a method for computing a circuit path between a source node and a destination node of a network includes identifying at least a first element that is to be traversed by the circuit path such that the path passes from the source node, traverses the first element, then passes to the destination node. The method also includes routing a first segment of the circuit path automatically such that the source node and the first element are components of the first segment. In one embodiment, routing the first segment automatically includes routing the first segment automatically using a shortest path first algorithm.

Method and apparatus for computing a path through specified elements in a network

Optical systems of the present invention are configured in optical networks including a plurality of optical switch nodes interconnected by a plurality of optical transmission fibers, or other waveguides. The transmission fibers in the network can provide working and/or protection capacity for information, or communications traffic, being transmitted through the network. In various embodiments of the network, multiple diverse, working routes are provided on a single fiber path interconnecting a plurality of switch nodes. The multiple, diverse working routes can then be protected using a common protection fiber or path to provide shared protection. The switch nodes include optical switch configured to provide various levels of optical switching depending upon the network configuration. For example, line switches as well as optical cross-connects and routers can be deployed in the present invention to switch one or more wavelengths between the working and protection fibers. The optical systems can be further configured to carry lower priority traffic on the protection fibers or wavelengths during normal operation to increase the overall normal operating capacity of the system.

Nabil M. Badr

Papers

Optical communication network and protection methods