Cisco Technology, Inc.

Integrated Network Corporation

Hubbell Limited

Cisco Systems Inc.

Telesend, Inc.

Dagaz Technologies, Inc.

Craig Alan Sharper

Dev Vrat Gupta

Alan E Stone

Yu-Ren Brian Chen

Kent G Iverson

Sayuri Kuo Sharper

Nadia Sachs

Mick Henniger

Earl A Emerson

James J Wisniewski

Sanjay Aiyagari

Kyung-Yeop Hong

Warren Meggitt

Lynne A Reamer

Gregory M Coffeng

Fred E Glave

An apparatus for communicating packetized data over a communications link using a channel bank having a time division multiplexing addressing scheme, the communications link having a predetermined format for data transmitted over the communications link including a framing bit and a frame period defined by the framing bit, is provided wherein the apparatus comprises a plurality of channel units for generating packetized data, each piece of packetized data having a packet period corresponding to a sufficient amount of time to communicate the packetized data over the communications link, a system for allocating the communication link to a channel unit that is currently sending data over the communications link for the packet period, a system for skipping the framing bit when communicating said packetized data if the framing bit occurs during the packet period, a system for determining a next sender of packetized data over the communications link, the determining system being distributed over the plurality of channel units so that each channel unit independently determines whether it is the next sender, and a system for allocating the communications link to the channel unit that is the next sender of packetized data after said packet period so that the time division multiplexing addressing scheme of the channel bank is ignored, and the channel bank is communicating packetized data. A method for communicating packetized data over a channel bank is also disclosed.

System and method for communicating packetized data over a channel bank

Methods and apparatus for transmitting and receiving data using framing circuitry designed to generate data frames of a first duration at a first data rate. According to the invention, data frames are generated and decomposed at lower data rates than the rate for which the framing circuitry was originally designed, i.e., the first data rate. The framing circuitry is programmed to organize a data stream into a sequence of data frames of the first duration or to decompose such data frames into a data stream. According to the invention, such a sequence of data frames corresponds to a selected one of a plurality of equivalent data rates. Each of the equivalent data rates are lower than the first data rate.

Methods and apparatus for transmitting data in a public network

A priority scheme is based on an amount of preallocated bandwidth unused by channel unit ports. A first water level in a first bucket is associated with an amount of allotted bandwidth unused by the channel unit and a second water level in a second bucket is associated with an amount of unused allotted bandwidth exceeding an overflow level of the first bucket. A priority value is derived from the first water level when the first water level is above zero. The priority value is derived from the second water level when the first water level is below or equal to zero. In another aspect of the invention, the high priority value is determined by tracking a percentage utilization of allocated bandwidth for a predetermined number of time increments comprising a measurement time period.

Communicating packetized data over a channel using a dual leaky bucket priority scheme for assigning priorities to ports assigned to channels in a channel bank

A technique for distributed queuing in communication systems such as Asynchronous Transfer Mode (ATM) type access nodes which multiplexes data from multiple user nodes for transmission onto a trunk into the core of the network. A contention resolution mechanism for controlling user node access to the trunk is employed which uses the age of a queued cell as a contention resolution mechanism. The age information may be combined with other information such as priority or index number to further resolve access contention. The system permits implementation of first-in and first-out cell queue buffers that can efficiently support various traffic types such as voice, transaction processing, or aggregated traffic streams in which the order in which cells are processed should be maintained. The system is equally adaptable to situations in which each cell should have equal priority, rather than having priority assigned to particular ports. The system provides a low cost, fault tolerant, highly scalable mechanism for distributing the queuing intelligence of multiple line units, with no need for a central entity to make a decision as to access control.

Distributed FIFO queuing for ATM systems

A Scalable Multimedia Network providing integrated networking of data, voice, video and image services over a variety of access facilities including metallic loops, fiber/coax or digital fiber is disclosed herein. The SMN establishes customer initiated switched virtual circuits for all traffic types and directs them to the appropriate backbone network. The SMN is based on a distributed switching platform that includes a protocol adaptation capability which permits communications between customer premises equipment and potentially incompatible backbone networks or network servers.

Scalable multimedia network

An ADSL modem provides compensation for a nonlinear telephone impedance by predistorting transmit signals such that the voltage across the nonlinear impedance is correct independent of the impedance. Correcting the voltage across the nonlinear impedance reduces noise in the telephone due to intermodulation products generated in the voice band. The modem comprises a transmitter that includes (a) a signal source providing a source data signal and (b) a predistortion circuit for predistorting the source data signal to provide a modem transmit signal for coupling to a transmission loop having a nonlinear impedance coupled thereto. The modem device further includes a receiver for receiving a modem receive signal from the transmission loop. The source data signal comprises source digital words, each source digital word corresponding to a particular voltage level. The predistortion circuit includes a memory for mapping the source digital words to predistortion digital words, each predistortion digital word corresponding to a particular desired voltage level. The transmitter further includes a digital-to-analog converter for converting the predistortion digital words into the modem transmit signal. A feedback circuit coupled to the loop measures the distortion of the modem transmit signal to provide a feedback signal to the predistortion circuit that is indicative of the measured distortion. The predistortion circuit adjusts the amount of predistortion in response to the feedback signal.

Method and apparatus for voice frequency noise reduction in splitterless

Communicating packetized data over a channel using a dual leaky bucket

A Scalable Multimedia Network providing integrated networking of data, voice, video and image services over a variety of access facilities including metallic loops, fiber/coax or digital fiber is disclosed herein. The SMN provides a broadcast switch using a tiered system of buses. Channel units are made to interface to a bus of any tier depending on bandwidth requirements of the particular channel units. The SMN is based on a distributed switching platform that enables carriers to economically provide service to a small number of customers and add capacity incrementally as the customer base increases. The platform has a protocol adaptation capability which permits communications between customer premises equipment and potentially incompatible backbone networks or network servers.

A method for communicating packetized data over a communications link having a predetermined format including a framing using a channel bank having a time division multiplexing addressing scheme is disclosed in which a plurality of channel units may generate packetized data and the communications link may be allocated to a channel unit that is currently sending data over the communications link. The next sender of packetized data over the communications link may be determined by a system distributed over the plurality of channel units so that each channel unit independently determines whether it is the next sender. The communications link may be allocated to the channel unit that is the next sender of packetized data after the current sender of packetized data so that the time division multiplexing addressing scheme of the channel bank is ignored and the channel bank communicates packetized data. An apparatus for communicating packetized data over a channel bank is also disclosed.

A scalable Multimedia Network providing integrated networking of data, voice, video and image services over a variety of access facilities including metallic loops, fiber/coax or digital fiber is disclosed herein. The SMN establishes customer initiated switched virtual circuits for all traffic types and directs them to the appropriate backbone network. The SMN is based on a distributed switching platform that enables carriers to economically provide service to a small number of customers and add capacity incrementally as the customer base increases. The platform has a protocol adaptation capability which permits communications between customer premises equipment and potentially incompatible backbone networks or network servers.

A Scalable Multimedia Network providing integrated networking of data, voice, video and image services over a variety of access facilities including metallic loops, fiber/coax or digital fiber is disclosed herein. The SMN establishes customer initiated switched virtual circuits for all traffic types and directs them to the appropriate backbone network. The SMN is based on a distributed switching platform that enables carriers to economically provide service to a small number of customers and add capacity incrementally as the customer base increases. The platform has a protocol adaptation capability which permits communications between customer premises equipment and potentially incompatible backbone networks or network servers.

An interface circuit is provided for implementing zero-byte substitution (ZBS) in a channel unit or line card which couples a digital subscriber line, such as a basic or primary rate Integrated Services Digital Network (ISDN) line, to a T1 network or other digital transmission facility. On the transmit side, the occurrence of an all-zero data byte in a B channel of the ISDN interface causes a corresponding zero byte indicator (ZBI) flag to be produced in the D+ channel, and also causes the all-zero byte to be replaced by the preceding non-zero data byte rather than by a prescribed or predetermined data byte. On the receive side, the occurrence of a repeated data byte in a B channel is detected and causes the current data byte to be replaced by an all-zero byte to restore the original data. The ZBI flag is then used as an error check bit to verify that the reinsertion of the all-zero byte was correct.

Zero byte substitution method and apparatus for telecommunications

Loop circuits lacking byte alignment are tested by test equipment signals at 9.6 kbps transmitted over a DS.phi. format 19.2 kbps communication network. Upon indication of loss of 19.2 kbps framing, return signals from the loop are reformatted into a 9.6 kbps format by selecting proper return bytes using a logic system stored in an office channel unit (OCU).

Growing community of inventors

Los Altos, CA, United States of America

Craig Alan Sharper