Broadcom Corporation

Nortel Networks Corporation

Farivar Farzaneh

Michael Timothy Kauffman

Richard Karl Feldman

Kim K Banker

Gavin Bowlby

Christopher Alan Del Signore

Rajesh Gopal Nair

Gerry Ryan

A system for reducing the cost of network management by using a proxy agent and subchannel communications so fewer SNMP licenses and fewer protocol stacks are needed. Subchannel communication is achieved in a plurality of different embodiments. Embodiments having single subchannel transceivers, multiple transceivers, single multiplexer and multiple multiplexers are disclosed. An NMS process using routing table CRC to automatically detect when the NMS topology information is incorrect and automated topology discovery is disclosed. A process for automated discovery of redundant cables during automated topology discovery is disclosed.

Apparatus and method for unilateral topology discovery in network management

A system for transmitting subchannel data over the same media as high speed data, especially DC balanced high speed data. A digital transmitter receives subchannel data and modulates it onto a subchannel carrier as the host signal in the preferred embodiment using frequency shift keying. The FSK subchannel carrier is added by superposition to the high speed data signal. Because of the ability to have very narrow bandwidths for the passbands of digital IF filters, the receiver is more sensitive and less susceptible to the need for tuning to accommodate manufacturing variations in the rise times of the high speed data signals.

Digital subchannel transceiver for transmitting data

A system for reducing the cost of network managment by using a proxy agent and subchannel communications so fewer SNMP licenses and fewer protocol stacks are needed. Subchannel communication is achieved in a plurality of different embodiments. Embodiments having single subchannel transceivers, multiple transceivers, single multiplexer and multiple multiplexers are disclosed. An NMS process using routing table CRC to automatically detect when the NMS topology information is incorrect and automated topology discovery is disclosed. A process for automated discovery of redundant cables during automated topology discovery is disclosed.

A system for transmitting subchannel data over the same media as high speed data, especially DC balanced high speed data. A digital transmitter receives subchannel data and modulates it onto a subchannel carrier as the host signal in the preferred embodiment using frequency shift keying. The FSK subchannel carrier is added by superposition to the high speed data signal. At the receiver, a low pass filter filters out the subchannel carrier frequency components which are then amplified and subjected to a two-pole anti-aliasing filter to remove the third and fifth harmonics. Analog-to-digital conversion is followed by a digital mix down to remove the subchannel carrier component using a local oscillator at the subchannel carrier frequency. An FIR low pass filter having a triangular time domain response performs anti-aliasing and leaves as an output only frequency components at the positive and negative deviation frequency for Mark and Space. Mark and space detectors then determine the relative magnitude of the signal received at the positive and negative deviation frequencies in the complex phasor domain to determine when Mark and Space frequencies are being received. Because of the ability to have very narrow bandwidths for the passbands of the digital IF filters, the receiver is more sensitive and less susceptible to the need for tuning to accomodate manufacturing variations in the rise times of the high speed data signals.

A method and apparatus for generation of CRC generation/checker circuitry. A symbolic simulation-based algorithm to derive boolean equations for a parameterizable data-width CRC generator/checker is described. The equations generated are used to implement a data-flow representation of the CRC circuit in VHDL. The VHDL description is then synthesized into gates.

Growing community of inventors

Los Altos, CA, United States of America

Farivar Farzaneh