At+t Corp.

At&t Bell Laboratories

David J Hodgdon

Daniel S Greenberg

Thomas H Daugherty

Dennis L DeBruler

Douglas J Murphy

Subrahmanyam Dravida

Stephen Joseph Brolin

Michael W Andrews

Robert W DeMarco

Chandan Sarkar

Gordon D Woods

A communications switch communicates a message to a particular access network endpoint by forwarding an identification of that endpoint along with the message, link-by-link, through the access network, the forwarding being accomplished by using previously stored routing information identifying, at the switch and at each cross-connection point, a particular downstream link over which the endpoint can ultimately be reached. The links connecting the cross-connection points are multiplexed links supporting digital loop carrier and fiber-in-the-loop communications. The routing information is generated and stored automatically by having each network element report information about itself upstream into the network.

Method and apparatus for establishing connections in a communications

A communications switch communicates a message to a particular access network endpoint by forwarding an identification of that endpoint along with the message, link-by-link, through the access network, the forwarding being accomplished by using previously stored routing information identifying, at the switch and at each cross-connection point, a particular downstream link over which the endpoint can ultimately be reached. The links connecting the cross-connection points am time-division-multiplexed links supporting digital loop carrier and fiber-in-the-loop communications. The routing information is generated and stored automatically by having each network element report information about itself upstream into the network.

Communications access network routing

Disclosed is a communications network for peripherals in a digital loop carrier transmission system. A broadcast STAR network is employed so that all peripherals receive any message which is broadcast by any of the peripherals. No peripheral broadcasts without clearance from the active communications hub. Two hubs can be provided to alternatively act as the active hub. Each peripheral includes a controller which transmits a request to send signal, multiplexes the request to send signal with an outgoing message, receives clear to send signals, and demultiplexes the clear to send signals from an incoming message.

Peripheral communications network

Disclosed is a method and circuit for modifying the check code of a data packet based on a first seed to accommodate the addition or substraction of a header. A number of bits, which include a second seed, an exclusive OR function of the first seed and a portion of a header, and a string of zeros dependent upon the length of an incoming data packet, is sent through a CRC generator. The resulting CRC calculation and the incoming packet check code are exclusive ORed to produce a modified check code taking into account the addition or substraction of the header.

Modifying check codes in data packet transmission

Growing community of inventors

Parsippany-Troy Hills, NJ, United States of America

David J Hodgdon