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Inhibit Propagation of Messages Containing an Origin Address Parity Error

IP.com Disclosure Number: IPCOM000047160D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 60K

Publishing Venue

IBM

Related People

Lanier, CS: AUTHOR [+4]

Abstract

In certain closed-ring peer communication systems, messages arranged in frames are propagated from station to station within a network of computer-controlled stations linked in a ring. Each message frame contains address information defining the origin and destination stations for that message as well as other information including the body or data of the message. In such systems, each station is adaptable to switch automatically into a bypass configuration upon detecting an error condition at its interface to the ring. In the bypass configuration, a shunt connection is formed between the station's receiving and transmitting ports which effectively removes the station from the ring as a communicating element.

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Inhibit Propagation of Messages Containing an Origin Address Parity Error

In certain closed-ring peer communication systems, messages arranged in frames are propagated from station to station within a network of computer-controlled stations linked in a ring. Each message frame contains address information defining the origin and destination stations for that message as well as other information including the body or data of the message. In such systems, each station is adaptable to switch automatically into a bypass configuration upon detecting an error condition at its interface to the ring. In the bypass configuration, a shunt connection is formed between the station's receiving and transmitting ports which effectively removes the station from the ring as a communicating element. In particular circumstances, successive stations could enter the bypass configuration with a rippling effect which could unnecessarily prolong the recovery process. In the illustration of Fig. 1, assume that a message passed from station D to station A contains a parity error in the origin address portion of the message as perceived at station A. This error could be due either to faulty operation of transmitting equipment at station D or to faulty operation of reception equipment or logic at station A. Before station A could switch to the bypass configuration, the erroneous origin address would have propagated to station B. In the absence of any restrictions this would cause station B to enter the bypass mode.

Accordingly, successive stations would enter the bypass configuration in a rippling manner. This chain action, and the excessive delays that would be associated with it in bringing about the eventual recovery of the network, could be avoided by using the following procedure. Referring to Fig. 2, after detecting an origin address (OA) error, station A alerts its host computing system. A's computing system generates an alerting message which is sent to sta...