A feedback control system for congestion prevention in a cell (packet) switching communication network is described. Congestion control is accomplished by controlling the transmission rate of bursty traffic in the presence of high priority, voice, low speed statistical, high speed deterministic and multicast data. Because bursty traffic is relatively insensitive to delay, adequate buffercapacity can be provided at the network nodes in order to minimize bursty data cell loss. By monitoring the buffer queue lengths at the nodes, a control signal can be generated at each intermediate node indicating the state of congestion. Excess queue length indicates incipient congestion while short queue lengths indicate excess capacity. Queue status is forwarded to the destination node where it is interpreted and sent back to the source node as a feedback rate control signal using a 2-bit code. The source node regulates the rate of bursty data transmission over the cell network in accordance with the feedback control signal thus minimizing congestion and concomitant data loss while efficiently utilizing available network bandwidth.

Congestion control for cell networks

According to the present invention, a method and system provides the ability to assign requests for data objects made by clients among multiple network servers. The invention provides a distributed computing system and methods to assign user requests to replicated servers contained by the distributed computing system in a manner that attempts to meet the goals of a particular routing policy. Policies may include minimizing the amount of time for the request to be completed.

Method and apparatus for balancing the process load on network servers according to network and server based policies

A telecommunications switching system employing multi-protocol routing optimization which utilizes predetermined and measured parameters in accordance with a set of user priorities in determining the selection of a telecommunications path to be utilized for transmitting a data file to a remote destination. The switching system has a first memory for storing the data file to be transferred, a second memory for storing predetermined parameters such as cost data associated with each of the telecommunications paths, a third memory for storing a set of user priorities regarding the transmission of data files, and means for measuring the value of variable parameters such as file transfer speed associated with each of the telecommunications paths. Processor means are operatively associated with the second and third memories and the variable parameter measuring means for determining which of the plurality of telecommunications paths should be utilized for transferring the data file in accordance with the set of user priorities, the predetermined telecommunications path parameters, and the measured variable parameters. The switching system further comprises input means for allowing a user to change the user priorities in the third memory prior to transmitting a file.

Multi-protocol telecommunications routing optimization

A system for selecting options for modifying a network architecture in accordance with user preferences using a knowledge base and a database. The knowledge base includes rules to select modification categories and the database includes information on a plurality of equipment and a plurality of tariffs. To select the options, the system generates a base-line simulation from the network architecture, which base-line simulation includes performance data on the network architecture under a predetermined scenario. Modification categories based on the user preferences are selected using rules in the knowledge base, and equipment information and tariff information corresponding to the network modification categories are selected from the database to create modification options for the network modification categories. The modification options are evaluated using rules in the knowledge base. The system then generates a plurality of new simulations of the network architecture as modified by the modification options, and compares the performance data of the base-line simulation with performance data of the new simulations to specify differences in performance data between the base-line simulation and each new simulation. Finally, the modification options (each corresponding to one of the new simulations) are ranked using the specified differences in performance data between the base-line simulation and each new simulation, user preferences, and rules of the knowledge base.

Automated network simulation and optimization system

A packet communications system utilizes a route determining mechanism by identifying principal paths between the source and the destination in the system Principal paths are minimum hop count paths with a transmission delay less than a specified threshold Principal path links are accepted as legs of the optimum path, if feasible, ie, if the resulting load on the link is less than a specified principal threshold Secondary links are accepted only if the resulting load on the link is less than a specified secondary threshold, where the secondary threshold is less than the principal threshold All paths must also have a transmission delay less than a specified threshold Each request for a route includes the source node, the destination node, the load required, the maximum transmission delay and, if desired, the quality of service parameters which all of the legs of the route must satisfy A modified Bellman-Ford breadth-first search algorithm is used to identify the principal links and, using these principal link identifications, determining the optimum path

Method and apparatus for optimum path selection in packet transmission networks

In a communication network, in which a plurality of switching nodes are connected with each other through a plurality of relay lines and one of the switching nodes acts as a center node for network routing, the center node estimates the state of delay of data for every relay line on the basis of information previously inputted, indicating the communication network configuration, and the state of delay of data reported by each of the switching nodes, and informs each of the switching nodes of said estimated state of delay of data. Each of the switching nodes determines and selects the relay line giving the shortest delay of data for every destination, to which it outputs data, on the basis of the state of delay at the relevant switching node itself and that received from the center node.

Routing control method in a packet switching network

PURPOSE: To select a path minimizing the delay time by recognizing the delay time between all two stations in a network from network form information provided statically in the center and the delay time of each line obtained by the report of each exchange station and informing the estimated delay to each exchange station from an adjacent station to the destination. CONSTITUTION: A connection state table 20 stored in a node A provided for the center function as network form information represents how each node is connected to any path and is rewritten when the network form is changed. Each node estimates the delay time from the queue length caused at each path of its own station to the adjacent station and reports it as the estimated delay by using a packet periodically to the center. The node A having the center function forms the estimated delay table 21 based on the report from each node periodically or each report reception from each node. The content of the estimated delay table 21 represents the minimum value of the estimated delay from the adjacent station to the destination station when each node selects a sending path. COPYRIGHT: (C)1987,JPO&Japio

Jiro Kashio

Papers

Routing control method in a packet switching network

Routing control system in packet exchange network