Importance

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Abstract

In a network with a sending system networked to at least one receiving system, it is sometimes desirable to transfer relatively short messages between the sending system and receiving systems in a highly reliable yet highly efficient manner. The present invention defines two short message protocols, one of which relies on a statistical model and the other of which uses positive acknowledgement to track receipt of transmitted packets by intended recipient. In the statistical reliability mode messages are divided into a guaranteed minimum number of packets, with additional packets being added if the message length is insufficient to fill the guaranteed minimum number of packets. The positive reliability mode of the present invention periodically sets an acknowledgement flag in the packets transmitted for a message. Receiving systems send an acknowledgement in response to receipt of that packet. The sending system tracks receipt of acknowledgements by intended recipient and retransmits any unacknowledged packets so as to positively assure the packets are received. Receiving systems send negative acknowledgements to request retransmission of missing packets. Negative acknowledgement suppression is implemented at both the sender and receiver to prevent a flood of negative acknowledgements from overwhelming the network. When packets are missed, the receiver selects a wait time that must elapse before the negative acknowledgement is sent. The wait time is selected according to a refined probability density function that results in relatively few negative acknowledgements being sent early on and relatively more negative acknowledgements being sent later on.

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First Claim