International Business Machines Corporation

Clifford B Meltzer

Gordon Wesley Braudaway

Krishnamurthi Kannan

Thomas G Burket

Deborah J Kruesi

Robert B Hoppes

Kenneth J Parchinski

Gary J Whelan

Maurice J Bach

A system and method for distributing application-to-application network communications protocol processing. Host computers implement distributed API processing across a high speed I/O channel increasing throughput. The application API conforms to standard protocols but protocol processing is distributed using a cross-channel distributed sockets API at the session layer. This API allows multiplexing of data from one or more hosts to one or more front end routers managing network communications. Multiplexing increases network performance through parallel processing and advantageously employs host high speed I/O functions. Front end routers perform lower level protocol tasks necessary to exchange data over the communications network.

Network processor for transforming a message transported from an I/O

A system or scheme for automatic detection of and recovery from transmission errors in the asynchronous communication mode at the data link level with complete transparency at the higher levels is disclosed wherein the transmissions are in the form of a sequence of data packets, and an improved combination of end-of-text (ETX) bytes along with checksums is used in each data packet to detect errors. The ETX character is dynamically selected for each packet after the data comprising the packet has been assembled. This character is coded differently from the remaining character codes in its respective packet and is made the second byte thereof following the start-of-text byte (STX). The third byte in each packet is made the complement of the preceding ETX byte, the latter of which is also made the last byte in the packet. Thus, the second and last bytes in each packet are identical, and different from all the other bytes, and the third byte is their complement. Other bytes in each packet include: one byte indicating the location of the packet in a set in a given transmission sequence; a byte distinguishing the packet's set from other transmission sequences; two bytes indicative of the number of data bytes in the packet; one byte operating as a control character indicating the functional nature of the packet; data bytes; and, two checksum bytes which precede the last ETX byte. Among the advantages of transmissions using packets containing the foregoing improved combination of bytes, is the fact that all transmission errors will be detected and upon detection of an error in a packet, the transmitter is immediately notified and retransmission is carried out only from the erroneous packet rather than from the beginning of the entire sequence as in the prior art.

Protocol for handling transmission errors over asynchronous

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Ossining, NY, United States of America

Clifford B Meltzer