Cisco Technology, Inc.

Douglas E Duschatko

Andrew J Thurston

Robert A Hall

Lane Bryon Quibodeaux

Lane Byron Quibodeaux

Ali Najib Saleh

Rudolph B Klecka

David D Wilson

A frame timing adjustment apparatus is disclosed. The apparatus includes an ingress framing unit, an egress framing unit coupled to the ingress framing unit, and a framing control unit coupled to control the ingress framing unit and the egress framing unit. The ingress framing unit is configured to generate an adjusted frame by virtue of being configured to adjust a position of information within a frame. The egress framing unit is configured to frame on the adjusted frame. The framing control unit is coupled to control the ingress framing unit to generate the adjusted frame and the egress framing unit to frame the adjusted frame.

Method and apparatus for errorless frame timing adjustment

An OC-192 front-end application-specific integrated circuit (ASIC) de-interleaves an OC-192 signal to create four OC-48 signals, and decodes error-correction codes embedded in each of the four OC-48 signals. An error insertion circuit is also provided for verifying correct operation of encoding and decoding circuits. A desired number of errors may be programmed for insertion into the OC-48 data signals. Error insertion may be performed in an iterative fashion to insert into different data signals the desired number of errors, wherein the errors are placed within the code words of the data signals at different location permutations for each data signal. In one implementation, error verification is performed using an error accumulator located in the receiver, and means are provided for examining an error accumulator count of the error accumulator to see if the number of accumulated errors matches with the number of inserted errors.

Error insertion circuit for SONET forward error correction

A switching apparatus is disclosed that employs a relatively simple and inexpensive switching matrix, but which avoids interruption of existing connections when connections are added or removed. The switching matrix switches errorlessly by controlling the point in time at which switching occurs. Using such a technique, switching can be performed without disturbing the connections already configured in the switching matrix, and so is referred to herein as being non-blocking. Optionally, the incoming data can be rearranged to provide a larger window of time in which the switching matrix can be switched. In the case of a switch using an optical backplane, this also allows more time for various components of the system (e.g., clock/data recovery units) to re-acquire lock. The switching apparatus includes a switching matrix and control circuitry. The switching matrix has a matrix input, a control input and a number of matrix outputs, and is configured to receive an information stream at the matrix input. The information stream includes a number of portions, while the control circuitry has a control output coupled to the control input. The control circuitry is configured to initially configure the switching matrix to output the information stream at a one of the matrix outputs and to subsequently configure the switching matrix to output the information stream at another of the matrix outputs during a period of time during which the one of the portions is transiting the switching matrix.

Method and apparatus for a rearrangeably non-blocking switching matrix

In a data transmission network, such as SONET, a method and apparatus for the generation of a path Alarm Insertion Signal (AIS) at the output of each of a number of concatenated pointer processors in response to a failure at the input of any one of the pointer processors. Each of the pointer processors has an input, an output and a bidirectional terminal that is coupled to a common node. Each of the pointer processors includes circuitry coupled to the input, the output and the bidirectional terminal that causes a predetermined logic level to be asserted at the bidirectional terminal in response to the appearance of an error signal at its input and that causes an AIS to appear at its output in response to either an error signal at its input or the assertion of the predetermined logic level at its bidirectional terminal.

Path AIS insertion for concatenated payloads across multiple processors

A method of generating a parity value is disclosed. The method includes reading a word from a data stream, determining if the word should be included in a parity calculation, and including the word in the parity calculation, if the word should be included in the parity calculation, and ignoring the word otherwise.

Method and apparatus for detecting errors in a backplane frame

An apparatus and method for a synchronous optical network (SONET) includes ordering a plurality of signals of a first type in one or more line cards for transmit to one or more types of line cards, wherein the ordering of the first type of signals creates a plurality of independent signals of a second type, and transmitting the plurality of the first type of signals to the one or more types of line cards, wherein the independence of the signals of the second type permits the one or more types of signals of the second type to be in an arbitrary order. The method and apparatus includes ordering in a plurality of modules to assign to a variable A a number of basic modules on the one or more line cards, assign to a variable B a number of processors adapted for STS-N signals on the one or more line cards, calculate a variable C by dividing A by B, C being the number of basic module channels common to each of the processors, calculate a variable D by dividing C by three, D being a number of contiguous channels, divide each STS-N signal into N/D portions, each portion including up to D bytes, and for each portion of the STS-N signal, select one of the number of processors adapted for STS-N signals, and transmit the portion of the STS-N signal to the one of the number of processors.

Channel ordering for communication signals split for matrix switching

An apparatus and method for detecting concatenation of payload data for an communication circuit is disclosed, wherein the payload data is dispersed over a first integrated circuit and one or more subsequent integrated circuits. The method and apparatus include determining whether each of the one or more subsequent integrated circuits have all channels therein designated as concatenation slaves, and communicating the determination to the first integrated circuit, the determination indicating that the one or more subsequent integrated circuits. According to an embodiment, the method and apparatus further include coupling the first integrated circuits to the one or more subsequent integrated circuits. The apparatus and method further include detecting concatenation on a first integrated circuit of the one or more integrated circuits, assigning one or more bi-directional ports coupled to the first integrated circuit as an input port, assigning each bi-directional port coupled to the one or more subsequent integrated circuits as output ports, and if any one integrated circuit among the subsequent integrated circuits includes a channel therein designated as a slave channel, providing an active high signal to the output port, the active high signal coupled to the input port of the first integrated circuit.

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McKinney, TX, United States of America

Douglas E Duschatko