Lucent Technologies Inc.

At&t Intellectual Property I, LP

Paramasiviah Harshavardhana

Subrahmanyam Dravida

Bharat Tarachand Doshi

Yufei Wang

Wing Cheong Lau

Lotfi Benmohamed

Ajay Kumar Mittal

Robert W Bickerstaff

James King Brinkley

Elliott Bryant

Song C Chen

Pravin Kumar Johri

Kazem Anaraky Sohraby

Arik Kashper

Steven S Katz

Thomas S Giuffrida

Norman Farber

Muhammed Akber Qureshi

Oded Hauser

Frank N Hujber

Antonio Rodriguez-Moral

Srinivasan S Ravikumar

Manu Malek

Mahalakshmi Jairam

David Sugarmen

Stefano Baroni

Randolph Roy Kutz

Cathy Zima

Cathy Helen Zima

A telecommunications network model receives data regarding a telecommunications network and a customer's use of that network. The data includes information about nodes, link between nodes, tariffs, and customer usage. The received data is utilized to create a model of the telecommunications network. The model may then be utilized to optimize a customer's use of the network, optimizing for a lowest cost solution.

Information entry for network optimization

A network optimization application receives as input information about a telecommunications network and the current use of that network. An optimization is performed in order to generate a preferred network use configuration which minimizes price for one or more customers of the telecommunications network. Information utilized as input into the application includes network nodes (e.g., switches, central offices, customer premises), linkages among nodes, prices associated with the network, and current use of the network. The output network use configuration may be browsed using a configuration interface listing network elements and also a detail interface for viewing details of individual network elements.

Optimization for network utilization

A method and apparatus are disclosed for monitoring and signaling a path restoration using pre-computed restoration paths following a detected fault on a primary service path in a communications network. A fault occurring inside the restorable portion of a network in heterogeneous or multiple network environments can be distinguished from faults occurring outside the restorable network in accordance with the ANSI Tandem Connection Maintenance standard, T1.105.05-1994. Path restoration is activated only when a fault causing path failure occurs inside the restorable portion of the network. Each conforming node in the restorable portion of the network has the necessary monitoring, signaling and cross-connect functionality and databases to participate actively in real time restoration. Additional non-conforming network elements can be positioned between the restoration nodes without preventing path restoration. With the signaling architecture of the present invention, when an end-node detects a path failure caused by an in-network fault, it formulates a signaling message for restoring the failed path. The restoration signaling message is thereafter relayed from one node to another in the overhead or payload of signaling paths that occupy the same bandwidth that is subsequently used by the restoration path. Once a signaling message is transmitted to an adjacent node in the overhead or payload of a particular signaling path, the node that transmitted the message makes a cross-connect that replaces the signaling path with a segment of the restoration path whose set-up was requested in the transmitted signaling message.

Method and apparatus for signaling path restoration information in a mesh network

Methods and apparatus are provided for designing IP networks with substantially improved performance as compared to existing IP networks such as, for example, those networks designed under best-effort criteria. Particularly, the invention includes methods and apparatus for: computing worst-case and optimistic link capacity requirements; optimizing network topology; and determining router placement within a network.

Network topology optimization methods and apparatus for designing IP networks with performance guarantees

Link capacity computation methods and apparatus for designing IP networks with performance guarantees

A network architecture comprised of nodes and a transport network capable of recovering from failures within the network. The network architecture incorporates select functions into the nodes for managing the data flow between individual edge routers and their connection through core routers to the transport network. The select function allows an individual node to recover independently without signaling other nodes over the transport network. Utilizing the select function, the failure of a single core router can be recovered locally without recovery signaling over the transport network.

Dual-homing select architecture

Traffic demands are routed in a ring network by first determining an inter-ring path for a given demand, and then independently determining an intra-ring path for the demand on each of the rings in the inter-ring path. The intra-ring path provisioning is fully decoupled from the inter-ring path provisioning, such that the demand can be routed more quickly and efficiently. For example, both the routing direction and the interworking nodes for a dual ring interworking (DRI) connection can be determined independently for each of the rings of the inter-ring path. The invention may be implemented in the form of a hybrid centralized/distributed network architecture, in which a central operations system or other central controller determines the inter-ring path by applying a shortest path algorithm to a ring graph in which nodes represent rings in the network and links represent ring interconnections in the network. Ring controllers in the rings of the inter-ring path then each independently determine an intra-ring path for their corresponding rings. Although particularly well suited for use with DRI, the invention can also improve routing performance in single ring interworking (SRI) applications, as well as applications involving combinations of DRI and SRI.

Methods and apparatus for routing signals in a ring network

Capacity demands are routed in an network including at least one ring having a pair of hub nodes and a number of additional nodes. A pair of routing trees is generated for the ring, with each of the routing trees specifying paths between nodes of the ring, and having as its root a corresponding one of the hub nodes of the ring. The routing trees are utilized to route capacity demands from nodes of the ring to other portions of the network, such as other rings. The routing trees for a given ring of the network are configured such that the two hub nodes of the ring are adjacent in each of the routing trees of that ring. In addition, the routing trees for the given ring are directed edge disjoint, such that if a link corresponding to one edge of a tree fails, an affected demand is routed to the other hub node of the ring using the other routing tree of the ring. The network may further include of pairs of &ldquo;super&rdquo; hub nodes, with pairs of the hub nodes of rings in the network each being assigned to pairs of the super hub nodes. A pair of routing trees generated for a given pair of the super hub nodes is then utilized to route demands for capacity from one of the hub nodes to one of the super hub nodes.

Dual hubbed tree architecture for a communication network

A method and system for controlling overload at a network processor in a communications system. Messages relating to a plurality of types of calls, functions or processes (collectively, &ldquo;calls&rdquo;) received at a processor seeking access to processor resources are granted normal access when the delay in processing such messages does not exceed threshold values. When such delay exceeds a threshold, messages are blocked in numbers relating to, among other things, the number of messages allowed in a reference interval, message delay, the total number of blocked calls, the number of blocked calls of each type, the number of calls allowed in one or more preceding intervals and preferences between types of calls.

Multivariate rate-based overload control for multiple-class communications traffic

Router placement methods and apparatus for designing IP networks with performance guarantees

Distributed precomputation techniques for determining primary and/or restoration paths in an optical or electrical network. The invention provides a number of partially and fully asynchronous distributed precomputation algorithms which may be implemented, for example, by the nodes of an all-optical network, in which network links are constrained in terms of optical signal wavelength and failure isolation. A given distributed precomputation algorithm may include a first phase in which paths are allocated for capacity demands to the extent possible without resolving contentions, and a second phase in which contentions between demands for the same capacity are resolved. The first phase may implement a contention locking mechanism which locks a primary path of a given demand to prevent other demands from contending for the same capacity, and a link capacity control mechanism which involves storing a link status table at one or more nodes, the link status table listing a number of specific failures and demands which are affected by the failures. The second phase of the distributed precomputation algorithm reroutes paths previously allocated to one or more demands in order to free up capacity required for another demand, so as to optimize overall network capacity utilization.

Multi-phase process for distributed precomputation of network signal paths

Distributed precomputation of network signal paths with table-based link capacity control

Distributed precomputation of network signal paths with improved

Precomputation techniques for determining primary and/or restoration paths in an optical or electrical network. A hybrid centralized/distributed approach is provided in which certain information used in distributed precomputation is downloaded from a central controller of the network. The downloaded information is used as an input to a distributed precomputation algorithm implemented by the network nodes in order to provide improved performance. The central controller makes use of its knowledge of global network topology in computing the information to be downloaded to the nodes. The downloaded information generally represents network information which changes with less frequency than other network information processed by the nodes as part of the distributed precomputation algorithm. The information downloaded from the central controller may include, for example, network connectivity information, capacities for at least a subset of the links in the network, a subset of all possible routes between a source node and a destination node in the network arranged in an appropriate initial search order, a link contention index for each of the links in the network, and indices assigned to one or more of the nodes and links of the network, wherein the indices are used to determine an order of processing operations involving the one or more nodes and links of the network.

Hybrid centralized/distributed precomputation of network signal paths

Distributed precomputation techniques for determining primary and/or restoration paths in an optical network. The invention provides a number of partially and fully asynchronous distributed precomputation algorithms which may be implemented, for example, by the nodes of an all-optical network, in which network links are constrained in terms of optical signal wavelength and failure isolation. A given distributed precomputation algorithm may include a first phase in which paths are allocated for capacity demands to the extent possible without resolving contentions, and a second phase in which contentions between demands for the same capacity are resolved. The first phase may implement a contention locking mechanism which locks a primary path of a given demand to prevent other demands from contending for the same capacity, and a link capacity control mechanism which involves storing a link status table at one or more nodes, the link status table listing a number of specific failures and demands which are affected by the failures. The second phase of the distributed precomputation algorithm reroutes paths previously allocated to one or more demands in order to free up capacity required for another demand, so as to optimize overall network capacity utilization.

Distributed precomputation of signal paths in an optical network

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Marlboro, NJ, United States of America

Paramasiviah Harshavardhana