Method and apparatus for use in a network of the ethernet type, to improve performance by reducing the occurrence of collisions in the event of channel capture

Claim 2

For use in two nodes of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, a method for improving channel utilization and fairness of access, comprising the steps of: after a collision, determining whether this node, A, has initially won or lost access to a network channel; if this node A has initially won channel access, beginning to transmit a succession of data packets separated by standard or relatively short interpacket gap, IPG, intervals; in another node, B, that has initially lost access to the channel, selecting a relatively long IPG interval to ensure that node B operates as a receiver and to ensure that there will be no further collisions; starting separate back-to-back timers in nodes A and B when the first data packet is transmitted and received, respectively; checking the back-to-back timers in nodes A and B after every packet transmission and reception, respectively; upon expiration of the timer in node A, imposing a long delay during which further transmission of data is deferred, then selecting the long IPG interval for this node; upon expiration of the timer in node B, selecting the standard or relatively short IPG interval and initiating transmission of a data packet, whereby the long delay by node A permits node B to function as a back-to-back transmitter; wherein nodes A and B alternate transmit and receive functions without need for collisions to resolve contentions for the network channel.

Claim 3

For use in two nodes of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, apparatus for improving channel utilization and fairness of access, the apparatus comprising: means operable after a collision, for determining whether this node, A, has initially won or lost access to a network channel; means operable if this node A has initially won channel access, for transmitting a succession of data packets separated by standard or relatively short interpacket gap, IPG, intervals; means operable in another node, B, that has initially lost access to the channel, for selecting a relatively long IPG interval to ensure that node B operates as a receiver and to ensure that there will be no further collisions; means for starting separate back-to-back timers in nodes A and B when the first data packet is transmitted and received, respectively; means for checking the back-to-back timers in nodes A and B after every packet transmission and reception, respectively; means operable upon expiration of the timer in node A, for imposing a long delay during which further transmission of data is deferred, then selecting the long IPG interval for this node; means operable upon expiration of the timer in node B, for selecting the standard or relatively short IPG interval and initiating transmission of a data packet, whereby the long delay by node A permits node B to function as a back-to-back transmitter; wherein nodes A and B alternate transmit and receive functions without need for collisions to resolve contentions for the network channel.

Claim 4

For use in two nodes of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, apparatus for improving channel utilization and fairness of access, the apparatus comprising: means operable after a collision, for determining whether this node, A, has initially won or lost access to a network channel; means operable if this node A has initially won channel access, for transmitting a succession of data packets separated by standard or relatively short interpacket gap, IPG, intervals; means operable in another node, B, that has initially lost access to the channel, for selecting a relatively long IPG interval to ensure that node B operates as a receiver and to ensure that there will be no further collisions; means for starting separate back-to-back timers in nodes A and B when the first data packet is transmitted and received, respectively; means for checking the back-to-back timers in nodes A and B after every packet transmission and reception, respectively; means operable upon expiration of the timer in node A, for imposing a long delay during which further transmission of data is deferred, then selecting the long IPG interval for this node; means operable upon expiration of the timer in node B, for selecting the standard or relatively short IPG interval and initiating transmission of a data packet, whereby the long delay by node A permits node B to function as a back-to-back transmitter; wherein nodes A and B alternate transmit and receive functions without need for collisions to resolve contentions for the network channel.

Claim 5

For use in a node of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, apparatus for improving channel utilization and fairness of access, the apparatus comprising: a timer, the timer enabling operation of the node alternately in a back-to-back transmit mode and in a receive mode over a fixed duration; and means for selecting a standard or relatively short interpacket gap, IPG, interval when the node is in the back-to-back transmit mode, and a longer IPG value when the node is in the receive mode, whereby successive data packets can be transmitted while in the back-to-back transmit mode, with minimal contention for channel access, because a shorter IPG provides priority of channel access over another node using a longer IPG.

Claim 6

For use in a node of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, apparatus for improving channel utilization and fairness of access, the apparatus comprising: a timer, the timer enabling operation of the node alternately in a back-to-back transmit mode and in a receive mode over a fixed duration; and means for selecting a standard or relatively short interpacket gap, IPG, interval when the node is in the back-to-back transmit mode, and a longer IPG value when the node is in the receive mode, whereby successive data packets can be transmitted while in the back-to-back transmit mode, with minimal contention for channel access, because a shorter IPG provides priority of channel access over another node using a longer IPG.

Claim 7

For use in a node of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, a method for improving channel utilization and fairness of access, the method comprising the steps of: operating the node alternately in a back-to-back transmit mode in which the node transmits successive packets of data without intervening transmissions from other nodes, and in a receive mode; limiting the time of operation of the node in back-to-back transmit mode and receive mode; and selecting a standard or relatively short interpacket gap, IPG, interval when the node is in the back-to-back transmit mode, and a longer IPG interval when the node is in the receive mode, whereby successive data packets can be transmitted while in the back-to-back transmit mode, with minimal contention for channel access, because a shorter IPG provides priority of channel access over another node using a longer IPG.

Claim 8

For use in a node of a network employing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol for channel access, a method for improving channel utilization and fairness of access, the method comprising the steps of: operating the node alternately in a back-to-back transmit mode in which the node transmits successive packets of data without intervening transmissions from other nodes, and in a receive mode; limiting the time of operation of the node in back-to-back transmit mode and receive mode; and selecting a standard or relatively short interpacket gap, IPG, interval when the node is in the back-to-back transmit mode, and a longer IPG interval when the node is in the receive mode, whereby successive data packets can be transmitted while in the back-to-back transmit mode, with minimal contention for channel access, because a shorter IPG provides priority of channel access over another node using a longer IPG.