Browse Prior Art Database

Overlapped Acknowledgement for Asynchronous Networks

IP.com Disclosure Number: IPCOM000114320D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Olnowich, HT: AUTHOR

Abstract

Disclosed is a method for improving transmission performance through asynchronous, multi-stage switching networks. Said networks interconnect a plurality of nodes, and messages are transmitted across the network from a sending network adapter at one node to a receiving network adapter at another node. Normally there is a method of message acknowledgement (ACK) issued from the receiving network adapter back to the sending network adapter. Many systems return one ACK message for every data message received. This can almost double the network traffic (halving the network efficiency) when the data messages are short.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Overlapped Acknowledgement for Asynchronous Networks

      Disclosed is a method for improving transmission performance
through asynchronous, multi-stage switching networks.  Said networks
interconnect a plurality of nodes, and messages are transmitted
across the network from a sending network adapter at one node to a
receiving network adapter at another node.  Normally there is a
method of message acknowledgement (ACK) issued from the receiving
network adapter back to the sending network adapter.  Many systems
return one ACK message for every data message received.  This can
almost double the network traffic (halving the network efficiency)
when the data messages are short.

      Some circuit switches improve the ACK handshaking by using a
backward flowing line through the network, called ACCEPT, which can
be used to give an instantaneous acknowledgement of a successfully
received message as part of the data sending sequence.  This does not
require a separate ACK message in return over the network.  However,
even this method has a problem in that the ACCEPT is issued after the
transfer has completed and adds an additional time (t1) to every
transfer.

      The solution to improve efficiency is to overlap the t1 portion
and permit the sending node to begin the next transfer without
waiting for the previous ACCEPT.  An earlier solution accomplishes
this by adding a second ACCEPT signal to the network interface, but
the present solution is more efficient because it accomplishes the
same result without requiring an increase in the network size.

      The implementation of the present solution requires that when a
message transmission period has completed, that the network
connections no longer be held active until after the t1 period.
Instead, the network connections are broken in two phases.  At the
completion of the message transmission (before t1) all network
connect...