US 6,721,335 B1Granted

Segment-controlled process in a link switch connected between nodes in a multiple node network for maintaining burst characteristics of segments of messages

AssigneeInternational Business Machines Corporation

InventorThomas Anthony Gregg

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Abstract

Defines and handles segments in messages to place pauses and interruptions within the communication of a message between transmitted segments of the message. A common link switch is used in a network to connect links to all nodes, the segment structures in each message is preserved when packets of each message are passed within the switch to a switch transmitter connected to the destination node indicated in each packet of the message for transmitting each of the message segments. Each transmitter stores the source identifier of the first packet it transmits for a segment and then gives priority to transmitting packets which contain source and destination identifiers which match the current transmitter stored source identifier and match the destination node connected to the transmitter. This priority enables each switch transmitter to interleaves segments of concurrent messages while preserving the segmentation of transmitted packets to maintaining a maximum network communication rate for the messages. When an unexpected wait occurs within a transmitting segment, which exceeds a predetermined time-out period, a transmission of any other waiting segment is started, which improves the message transmission efficiency in the network.

A method of communicating messages from a message sender node to a message receiver node in a multi-node network, comprising

connecting each node in a network to a communication link which connects to a common link switch (switch) in the network for forwarding a message packet sent from any node (operating as a source node of a transmitted message packet) to a port of any other node (operating as a destination node receiving the message packet),
transmitting in a header of each packet of each message a contained source node address and destination node address of the packet,
segmenting a sequence of packets transmitted by a source node by indicating a last packet transmitted for each segment,
receiving each packet of a segment at a receiver in the switch,
storing a respective source node address for each transmitter in the switch for indicating the source node address of a first packet of a current segment being transmitted by the transmitter,
comparing the source node address currently stored in the transmitter to the source node address in each packet currently received by each receiver of the switch,
selecting as a next packet for transmission by the transmitter any currently received packet having a source node address comparing equal with the source node address stored for the transmitter and containing a destination address equal to the destination address of the node connected to the transmitter in order to keep the packets of the segment together in time,
setting a “within a segment” indicating field for each transmitter to indicate a “within a segment” state when the transmitter transmits a packet which is not the last packet of a segment,
resetting the “within a segment” indicating field to indicate a “not within a segment” state for the transmitter when a packet is received which is the last packet for the current segment being transmitted by the transmitter, and
testing for the “within a segment” state of the transmitter before transmitting a currently received packet.

7 more elements

Abstract

Claims3