US 4,669,113 AGranted

Integrated network controller for a dynamic nonhierarchical routing switching network

AssigneesAT&T Corp., AT&T Bell Laboratories, AT&T Communications

InventorsGerald R. Ash, Billy B. Oliver

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Abstract

A nonhierarchial switching system employing a modified unified algorithm for developing link sizes for paths that connect switches in the system and routing sequences for the switches in the system, and further employing means for updating the routing sequences to minimize potential blocking in the network. In one embodiment, the modified unified algorithm develops improved link size determinations by taking advantage of traffic sensitive dynamic routing on the alternate paths available in the nonhierarchial switching system for connecting any switch to any other switch in the system. Updating of the routing sequences is achieved in that embodiment by evaluating the least loaded path for each potential connection of two switches in the system and, when appropriate, by installing the least loaded path as the second choice path in the routing sequence for that potential connection.

Claims16

Dependent claims

A nonhierarchical switching network system comprising switches, links interconnecting said switches, means within each of said switches to originate a connection to any other one of said switches based on path information stored within each of said switches that originate a connection (originating switches) (OS), a controller, and means for each of said switches to send traffic and link capacity information to said controller characterized by:

means for computing for each of said originating switches a first path choice and an ordered group of subsequent path choices comprising second and subsequent choice paths, corresponding to each connection of the originating switch to other ones of said switches;
means for communicating to each of said originating switches path choices computed therefor by said means for computing;
means for developing updated path choices for connection of each of said switches to each other of said switches based on a least loaded path approach in accordance with said traffic and link capacity information;
and
means for installing said updated path choices at the head of corresponding ones of said ordered groups of subsequent path choices, thereby making said updated path choices the second choice paths and pushing down in order said second and subsequent choice paths in said groups of subsequent path choices.

2 more elements

In a switching network system having a plurality of switches and multi-trunk links interconnecting said switches, where any one of said switches serving as an originating switch (OS) may connect to any other of said switches serving as a terminating switch (TS), where path selection is made by said OS in accordance with information provided by a common controller and stored in said OS, and where traffic information and idle trunk information is sent by said network to said common controller, the improvement in said controller comprising:

first operational means responsive to said traffic information representing a traffic load for computing a first path choice and subsequent path choices consisting of second and succeeding path choices for each potential pairing of an originating switch and a terminating switch (OS-TS pair) in said network, developing thereby a routing sequence for each of said OS-TS pairs;
second operational means responsive to said traffice and idle trunk information for computing at least loaded path for each of said OS-TS pairs;
third operational means responsive to said traffic information for enabling replacement of said second path choice in said routing sequence for each of said OS-TS pairs with said least loaded path computed by said second operational means corresponding to each of said OS-TS pairs;
and
fourth operational means for communicating to each OS in said network said routing sequences and said least loaded path replacement for said second path choices for said OS.

2 more elements

Dependencies are inferred from the claim text.