Bell Communications Research, Inc.

Telcordia Technologies, Inc.

Other

Teunis J Ott

Tirunell V Lakshman

Komandur R Krishnan

Arnold Leslie Neidhardt

Mohammed A Tabatabai-Yazdi

Methods and systems for estimating the number of active connections in a node in a communications network are described. The node estimates the number of active connections, without maintaining state information on each connection in the node, by sampling one or more packets in a buffer in the node when the node receives a packet, determining the number of sampled packets that are associated with the same connection as the received packet, and estimating the number of active connections in the node based on the determined number of the sampled packets. The node stabilizes the number of packets in the buffer by estimating the number of active connections in the node based on a sampling of the packets in the buffer when the node receives a packet, determining a probability for discarding the received packet based on the estimated number of the active connections and the recent buffer occupancy, and discarding the received packet according to the determined probability.

Method and system for stabilized random early detection using packet sampling

A method and system for dynamically adjusting the total bandwidth that an asynchronous transfer mode (ATM) switching system can make available to Available Bit Rate (ABR) virtual circuits comprise the steps of by determining a set of weighted &ldquo;cutoffs&rdquo; for the ABR virtual circuits, respectively, determining a first total expected rate (Exp_Rate) for recently active virtual circuits that are bottlenecked elsewhere based on the weighted cutoffs, setting a second total expected rate for active virtual circuits that are bottlenecked elsewhere to the first total expected rate, determining a total bandwidth available in the switching system for active virtual circuits that are bottlenecked in the switching system based on the first total expected rate, and setting to zero the first total expected rate. Furthermore, the method and system dynamically adjust the total bandwidth that the switching system can make available to ABR virtual circuits by recomputing, at fixed time intervals, the total bandwidth that is available to the active ABR virtual circuits that are bottlenecked at the switching system.

Method and system for dynamic allocation of bandwidth in asynchronous transfer mode (ATM) switching systems

Methods and systems for determining the number of active connections in a node in a communications network are described. The node determines the number of active connections by sampling a list of recently active connections in the node when the node receives a packet, and estimating the number of active connections based on whether the packet is associated with a sampled entry in the list. Each entry in the list includes a connection identifier and a count. The node stabilizes the buffer occupancy by estimating the number of active connections in the node based on a sampling of the list of recently active connections when the node receives a packet, determining a probability for discarding the packet based on the estimated number of active connections and the recent buffer occupancy, and discarding the packet according to the determined probability. Finally, the node monitors the connection associated with the received packet when the connection is associated with the connection identifier in a sampled entry, the count of the sampled entry exceeds a first predetermined threshold, and/or a total occurrences of the connection identifier in the list exceeds a second predetermined threshold.

Method and system for stabilized random early detection using connection sampling

A method for transmitting packets or cells (or both) in a communications network 10 is disclosed. The packets or cells are transmitted along a forward communications path in a network from a source node h1 via one or more intermediary nodes r1, x1, r5 and r2 to a destination node h4. At the intermediary nodes r1, x1, r5 or r2, the packets or cells are received in a buffer 38 or 42-1 to 42-4. The packets or cells are transmitted along the forward communications path according to a transmission schedule. In the presence of congestion at one of the intermediary nodes x1, an indication of the congestion is provided to the destination nodes h4 of the first packets to be transmitted according to the schedule. An indication of the congestion of the first packets or cells is provided by the destination nodes h4 of the first packets or cells to the source nodes h1 of the first packets or cells via a feedback communications path.

Drop from front of buffer policy in feedback networks

A methodology and concomitant circuitry for smoothing delay sensitive traffic utilizes short term traffic forecasts and guarantees meeting a prespecified delay constraint. The pattern of incoming traffic is used to forecast estimates of future incoming data from the present and past incoming data. Corresponding to the estimate is a data rate for propagating stored data to produce a smoothed outgoing data rate, and the interval of time over which such a rate is used so as to satisfy the delay constraint. The estimation procedure is then re-invoked at the end to the time interval, which takes into account data arriving during the time interval, so as to determine the next succeeding data rate and a new time interval for propagating stored data.

Smoothing delay-sensitive traffic offered to asynchronous transfer mode

A process is disclosed for routing service requests through a network comprising nodes interconnected with links. The network is also arranged so that each node may communicate with each of the other nodes. At preselected time intervals, sets of routes through the network are generated in response to the network configuration and traffic information. Also, at predetermined time intervals, occupancy factors are computed as determined by the network configuration and in response to traffic information. These occupancy factors are proportional to unassociated occupancy factors and allocation factors associated with calls of the various node-pairs; each of these latter factors is derived from a nominal routing scheme in which a call of the corresponding node-pair is treated as lost only if it is blocked on all of its permitted routes. Upon a request for service, the occupany factors corresponding to the busy-idle status of the links are used to compute an occupancy value associated with each of the end routes. Each route is converted to a candidate route based on traffic load at the initiation of the service request. The minimum occupancy value for each set of routes is selected as the candidate route for bridging a given node pair. If this minimum value is less than a preselected threshold, the traffic is routed over this candidate route, thereby satisfying the service request. Otherwise, the request is denied.

Routing of network traffic

A process is disclosed for routing service requests through a network comprising nodes interconnected with links. The network is also arranged so that each node may communicate with each of the other nodes. At preselected time intervals, sets of routes through the network are generated in response to the network configuration and traffic information. Also, at predetermined time intervals, occupancy factors are computed as determined by the network configuration and in response to traffic information. Upon a request for service, the occupancy factors corresponding to the busy-idle status of the links are used to compute an occupancy value associated with each of the routes. Each route is converted to a candidate route based on traffic load at the initiation of the service request. The minimum occupancy value for each set of routes is selected as the candidate route for bridging a given node pair. If this minimum value is less than a preselected threshold, the traffic is routed over this candidate route, thereby satisfying the service request. Otherwise, the request is denied.

Growing community of inventors

Chester, NJ, United States of America

Teunis J Ott