Cisco Technology, Inc.

Anix Anbiah

David A Hillard

Jin Huai

Gary Baldwin

Suresh Katukam

Methods and apparatus for enabling a protected circuit path to be created efficiently are disclosed. In accordance with one embodiment of the present invention, a method for creating a protected circuit path within an optical network system includes identifying a first node, a second node, and a third node. Once the nodes are identified, a pseudo link or a virtual link may be created between the second node and the third node. A first circuit path is then routed between the first node and the second node, and a second circuit path which protects that first circuit path is routed between the first node and the third node using the pseudo link.

Computing a path for an open ended uni-directional path protected switched ring

Disclosed is a method and associated apparatus for automatically propagating circuit information in a network. In one embodiment, a network includes multiple circuit switches that are coupled using communications links. Information relating to the communications links are automatically propagated in the network using a protocol used by routers in communicating with other routers.

Automatic propagation of circuit information in a communications network

The invention provides a method and system for enhancing the capability to optimally route VT circuits over SONET networks. The invention discloses a method for identifying Network Elements (NEs) that have VT capability (i.e., VT cross connect capability) and, when desired or required for VT circuit routing, manually or automatically topologically interconnecting these NEs by STS-1 circuits called VT Tunnels. Once interconnected, these VT Tunnels are suitable for supporting user VT traffic without the network operator being required to upgrade non-VT NE with VT capability or without having to exhaust the limited pool of available VT cross connects on one or more NEs.

Method and system for optimized routing and protection of VT traffic in SONET networks

A method for identifying and choosing a shortest path segment that has an alternate edge disjoint path segment. While routing Unidirectional Path Switched Ring (UPSR) path segments in a graph, there may be several equal distance paths to choose the shortest path from. Choosing a certain path as the shortest path may minimize or eliminate the chance of finding an alternative path segment. A method is provided such that if multiple shortest paths from the source node to a particular destination node exist, the method selects the shortest path which has an alternate edge disjoint path, and which can be used for path protection. The particular shortest path chosen by the method is not necessarily the first shortest path constructed.

Method and apparatus for discovering edge-disjoint shortest path pairs during shortest path tree computation

The invention comprises a method for computing the shortest protectable paths in communication networks, and a method for establishing and defining protected paths. The invention utilizes a new algorithm to exclude from consideration as the &ldquo;shortest path&rdquo; between two network elements, a path for which adequate protection cannot be established. Such an unprotectable path will contain one or more unprotectable links. These unprotectable links can be identified and excluded based upon whether or not the link is a member of a loop. Because there are several more computational steps in defining the protected paths, after the shortest path has been found, the initial exclusion of unprotectable path segments from consideration eliminates the potential waste of computational resources leading to a more rapid and efficient routing and provisioning of reliable network paths and circuits.

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Rohnert Park, CA, United States of America

Anix Anbiah