At+t Corp.

Lucent Technologies Inc.

Alcatel-lucent USA Inc.

David James Houck, Jr

Pravin Kumar Johri

Kathleen S Meier-Hellstern

Cagatay Buyukkoc

Rodolfo Alberto Milito

Steven M Michelson

Gopalakrishnan Meempat

Kin K Leung

Kamlesh T Tewani

Wai Sum Lai

Huseyin Uzunalioglu

Peter M Winkler

Lev Slutsman

David Frederick Lynch

Om Prakash Mahajan

James Anthony Schmitt

Kamala Prasad Das

Lance Wayne Wilson

Luiz Antonio Vitoria

Mei Deng

Sebastian Cwilich

Dicky Chi Kwong Yan

Ken Ambs

Method for admitting new voice calls to a VoIP network. Various points in the network are polled to generate a link utilization parameter. Parameters denoting threshold values of link utilization in the network are compared to the link utilization parameter. A first comparison is made between a first (current) link utilization parameter and first and second link utilization threshold parameters. Then, a second comparison is made between the current link utilization parameter and a second (previous) value of link utilization. A calculation of new calls allowed into the network is performed based on these comparisons and whether the current level of link utilization is rising or falling when compared to a previous level of link utilization.

Method for management of voice-over IP communications

A method for managing calls of various relative priority levels in an IP network includes polling at least one location in the network to obtain information indicative of a level of utilization said at least one location and computing a status of utilization of said at least one location based on said polled information and assigning a decision policy to said status. A priority level of a new voice call requesting to enter the network is then assessed against relative to priorities of existing calls on the network and the decision policy is invoked on the new voice call according to its relative priority level to the existing calls on the network and the decision policy in effect at the time the new voice call requests entry to the network.

Method for management of voice-over IP communications of various relative priority levels

A method and apparatus is provided for setting up an IP session from a first node, across a network that uses direct virtual path routing, to a second node. The first node receives a request to set up the session. The second node is identified as the destination of the session, based on the request. A first stack of labels is obtained that defines a first path. A second stack of labels is obtained that defines a second path. A first label identifier is selected that identifies the session in a first direction. A second label identifier is selected that identifies the session in a second direction. Finally the data is transmitted from the first node to the second node and from the second node to the first node using the first stack and second stack of labels and label identifiers, respectively.

Integrating switching and facility networks

The problems associated with prior solutions for implementing ATM or IP/MPLS in a large-scale network are overcome by providing an efficient means by which capacity in the network is more fully shared without adversely affecting call or session setup latency, and at the same time simplifying network operations. This is achieved by performing the functions of route setup, route allocation, and capacity management in a network at the edges (e.g., the interfaces existing between each ATM switch or IP/MPLS router and customers) of the network. In accordance with the principles disclosed herein, the edges contain nodes that form the interface between the ATM switches and IP/MPLS routers and the link(s) that interconnect them and the outside world. These nodes comprise controllers and other apparatus that in some cases may be incorporated in, or connected as adjuncts to, the ATM switches or IP/MPLS routers.

Integrated switching and facility networks

An admission control and load balancing system controls admission of packet streams or calls to a network and balances the packet traffic across the network, improving quality of service. The system includes a central database which stores information including cost data associated with individual paths and links across the network. A processor, in communication with the database, coordinates the admission control and load balancing decisions, and updates of the database cost data to reflect the dynamic network conditions, based on input from appropriate data sources. In one embodiment, referred to as the exact algorithm, the database is consulted by the admission control points or gatekeepers prior to admitting each arriving packet stream, and the database contents are updated call-by-call to reflect the allocation of resources to each admitted stream. In another embodiment, referred to as the inexact algorithm, control decision as well as database updates occur on a periodic rather than on a call-by-call basis to promote better scalability. In this embodiment, the processor periodically calculates admission decisions based on cost data in the central database. These admission decisions are then periodically forwarded to a satellite database associated with each gatekeeper, for storage and use in admission decisions until the next update epoch.

Method and apparatus to provide centralized call admission control and load balancing for a voice-over-IP network

A method and apparatus to control call admission to a packet-based network and achieve load balancing over a packet-based network includes at selected times generating and sending a path status message along a defined path, such as an MPLS path, through the network. As the message travels along the path, a cost metric field within the message is updated. The cost metric may reflect available bandwidth, or percentage utilization of the aggregate bandwidth, on the most congested (bottleneck) link in the path that it tracks. The cost metric is determined for each link at a data measuring point, such as individual routers, along the path. The optimum path between two gateways is determined, and further packet streams are routed onto the optimum path. In the event that no paths between a source and destination gateway meet predetermined utilization criteria, a packet stream block indicator is set which shows a requesting edge router that no paths are currently available for a packet stream requesting routing between particular source and destination gateway. The path utilization status message may be generated alternately in routers or in a master gateway. In either case, the messages are sent and the status of the network is determined in a distributed fashion at selected times, such as a regular timed interval.

Distributed call admission and load balancing method and apparatus for packet networks

A method and system are provided for computing an optimal restoration capacity and/or optimal restoration paths for a network to resolve a restoration scenario by solving a linear program (LP) model. The LP model includes decision variables corresponding to restoration capacity and restoration paths and constraints requiring restoration of traffic and conservation of capacity in the network. For example, the system determines a set of network paths that need to be restored in the network, preprocesses network data corresponding to the network to reduce LP processing workload and time; generates possible restoration paths and solves the LP model, preferably through column generation methods, to determine the optimal restoration capacity and/or the optimal restoration paths to resolve the restoration scenario; changes the LP solution into integer form, as necessary, and changes the LP solution in integer form to the original format of the network data or an equivalent thereof.

Optimizing restoration capacity

A method is provided for setting up a communication from a first edge node, across a network that uses direct virtual path routing, to a second edge node. The first edge node receives a request to set up the communication. The second edge node is identified as the destination of the communication, based on the request. A first virtual path identifier (VPI) is obtained that defines a first path from the first edge node across the network to the second edge node. A second VPI is obtained that defines a second path from the second edge node across the network to the first edge node. The first and second VPIs are selected by a routing status database. A first virtual channel identifier (VCI) within the first VPI is selected. A second virtual channel identifier (VCI) within the second VPI is selected. Data is transmitted from the first edge node to the second edge node using the first VPI and first VCI, and from the second edge node to the first edge node using the second VPI and second VCI. Switches adapted to carry out the method are also provided.

Integrating switching and facility networks using ATM

An efficient approach and corresponding apparatus for selecting virtual paths in a network for routing datagrams achieves effective sharing of capacity without adversely affecting call setup latency. Edge nodes of the network assign calls to virtual paths based on the destination of the call and the current load status of each of a relatively small number of paths. Each call is assigned a VPI (Virtual Path Identifier) corresponding to the path chosen and a VCI (Virtual Circuit Identifier) corresponding to the identity of the call at that edge node. The ATM backbone nodes route calls based solely on the VPI. Capacity management and load balancing is achieved by each edge node keeping track of the load on each access link from its edge node to the rest of the network and of the congestion status of the various links in the network. In one embodiment, the edge node periodically sends information about its usage of the network to a &ldquo;central fabric network interface&rdquo; which combines information from all edge nodes, evaluates congestion status for the network links, and forwards that information back to the edge nodes.

An efficient approach and corresponding apparatus for selecting virtual paths in a network for routing datagrams achieves effective sharing of capacity without adversely affecting call setup latency. Edge nodes of the network assign calls to virtual paths based on the destination of the call and the current load status of each of a relatively small number of paths. Each call is assigned a VPI (Virtual Path Identifier) corresponding to the path chosen and a VCI (Virtual Circuit Identifier) corresponding to the identity of the call at that edge node. The ATM backbone nodes route calls based solely on the VPI. Capacity management and load balancing is achieved by each edge node keeping track of the load on each access link from its edge node to the rest of the network and of the congestion status of the various links in the network. In one embodiment, the edge node periodically sends information about its usage of the network to a 'central fabric network interface' which combines information from all edge nodes, evaluates congestion status for the network links, and forwards that information back to the edge nodes.

A data synchronization system, which in one embodiment, uses a ShuffleNet topology requiring an even number, N=2m, of nodes in the system. These nodes are organized into two sets, X=x.sub.0, . . . , x.sub.m-1 and Y=y.sub.0, . . . , y.sub.m-1, wherein the subscripts are always to be taken modulo m. Each 'round' of communication entails simultaneously synchronizing the nodes in X with nodes in Y according to a matching between the two sets. The rounds are grouped into two 'batches,' batch B.sub.j which consists of rounds R.sub.2j-1 and R.sub.2j-2 for j.gtoreq.1. During each odd batch B.sub.2j-1, each x.sub.i synchronizes with y.sub.2i+2j-2 and with y.sub.2i+2j-1. In another embodiment, the data synchronization is based on a hypercube scheme, wherein each node is labeled by a binary string and any two nodes with their labels differing by one bit are connected by an edge and only adjacent nodes, i.e. those nodes connected by an edge, can communicate and exchange data directly according to an update schedule. In a third embodiment, a hypercube scheme is used, but the number of nodes is assumed to be a power of 2 or N=2.sup.m. This embodiment, like the second embodiment, uses the labeling of nodes by their binary representation, but the matchings of nodes used to determine the update schedule is not confined to the hypercube edges. Instead, a general cyclic matching scheme is used.

Synchronization methods for distributed processing systems having

A method of routing an interim NP call in which it is determined to give a called number interim NP redirection rather than conventional RCF redirection when the called number is to be ported. When a ported call is to receive interim NP redirection and SS7 networking is used, an Initial Address Message for the call is created with the Called Party Number parameter of the Initial Address Message populated with the Location Routing Number for the switch to which the called number has been ported. The Generic Address Parameter of the Initial Address Message is populated with the called number and the M bit of the Forward Call Indicator parameter of the Initial Address Message is set. The call is then redirected to the switch to which the called number has been ported based on the Location Routing Number in the Called Party Number parameter of an Initial Address Message. This method avoids the use of RCF 'shadow numbers' and the need to query an external long-term NP database.

Method for routing an NP call

A system and method are described for assigning downstream and upstream communication pathways in broadband access networks, such as networks based on the hybrid fiber-coax architecture. In the upstream direction, frequency channel and time slot assignments use a packing opposite methodology, which is dependent on the type of service request. The system assigns the lowest time slot in the lowest frequency available for a DSO service request and the highest time slot in the highest frequency which has the next four contiguous time slots available for an H0 service request. To optimize upstream bandwidth efficiency, a H0 channel occupying the space of four contiguous time slots is used to carry up to six simultaneous voice conversations. A method is described that governs such use of H0 channels by NIUs according to their offered loads. In the downstream direction, network interface units are automatically assigned frequencies in response to the expected load across the available frequency channels and are made to spread evenly the load across all downstream frequency channels. In one embodiment, assignments are based upon each individual network interface unit load, each network interface unit group load, the capacity of each network interface unit group and the blocked load. An assignment will be made to the group having the maximum idle capacity, i.e., the group which has the greatest blocked load differential. That is, assignments are made if moving an individual NIU from a first NIU group to a second NIU group results in a blocked load differential greater than the cost ratio R, where R represents the cost of moving an NIU divided by the cost.

Growing community of inventors

Colts Neck, NJ, United States of America

David James Houck, Jr