Other

Sartre Satire LLC

Feng Han

Chris Tsu

Andy P Annadurai

Mohammed Abdul Rahman

Hon-Ming Li

Hong-Ming Li

Method and apparatus for processing data packets within a communication system such as a synchronous optical network (SONET) detect an invalid byte and drop and shift bytes of data to address an invalid byte. A method according to one embodiment of the present invention, includes receiving a first data packet in the communication system. Thereafter, it is determined whether this packet ends with both a valid byte and an invalid byte of data. If both the valid and invalid bytes are present, the invalid byte is dropped and a valid byte from a succeeding data packet is concatenated with the valid byte of the first data packet, and byte shifting occurs in the succeeding data packet. Byte shifting continues until a second packet ending with an invalid byte is encountered. Skipping a clock cycle at the end of the second packet with the invalid byte results in packets with only valid data.

Circuit and method for processing communication packets and valid data bytes

A method and circuitry for detecting a pattern in received data such as the A1A2 boundary in a SONET frame after deserialization. Two consecutive pluralities of bytes of incoming data are stored and compared with the A1 and A2 values (or bit shifted versions of the A1 and A2 values) until the boundary is detected. The data are then bit shifted so that every byte on the bus is either A2 or A1. A new aligned data bus is then formed such that the last A1 bit occurs on the data bus for a given clock cycle and the first A2 bit occurs on the data bus during the next clock cycle.

Method and circuit for processing data in communication networks

Method and circuitry for de-skewing data in data communication networks such as a SONET. The data is sent from a system chip to a framer chip where the data is de-skewed. To detect data skew, the system chip sends a training sequence to the framer chip. The information bits sent to the framer chip are searched in order to detect the training sequence. The training sequences contain clear transition patterns at which all 16 bits of the transmit data and the TCTL signal line are inverted. If any bit does not invert, this bit must be a skewed bit. Based on the data one clock cycle before and one clock cycle after this transition, the skewed bit can be corrected back. After the data skew is detected, a multiplexing logic circuitry is used to correct the skew based on one clock cycle either before or after the transition. The multiplexing logic circuitry includes at least three registers coupled to the inputs of the multiplexing logic circuitry.

Method and circuit for de-skewing data in a communication system

A cyclic redundancy check (CRC) generator, in accordance with a specific embodiment of the present invention, generates a 32-bit CRC for each packet whose data bytes are carried over a 128-bit bus by first dividing the data bytes by a 123degree generator polynomial and subsequently dividing the remainder of the first division by a 32degree generator polynomial. Data bytes of a new packet are divided by a different dividing logic than those of a current packet. The remainder of division performed on the bytes of a new packet are supplied to the dividing logic adapted to divide the bytes of a current packet. The division by the 123degree generator polynomial is performed on a per byte basis, with the remainder of the division of the (i+1)byte being used in the division of the ibyte.

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Pleasanton, CA, United States of America

Feng Han