Signaling protocol for a noisy communications channel
First Claim
1. Apparatus to control the exchange of signaling messages between first and second data terminals, individual ones of the signaling messages requiring a response from the receiving terminal, said apparatus comprisingat the first data terminal, means, responsive to the input of a signaling message requiring a response message, for repeatedly transmitting the signaling message and repeating such transmission until said response message is received from a second receiving terminal,at the second data terminal, means, responsive to receipt of the signaling message, for repeatedly transmitting the response message until a confirmation message is received from the first data terminal, andat the first data terminal, means for transmitting said confirmation message responsive to receipt of each response message.
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Accused Products
Abstract
The retransmission of signaling messages that data terminals (e.g., modems) might exchange prior to exchanging user data is controlled by arranging a data terminal that receives multiple copies of the same signaling message so that it saves only the first copy thereof, but transmits a response to the sending terminal following receipt of each such copy. The sending terminal terminates its transmission of the signaling message upon receipt of a response from the receiving terminal. The inventive procedure is especially advantageous for controlling the retransmission of signaling messages during a n-way handshake between two terminals.
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Citations
5 Claims
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1. Apparatus to control the exchange of signaling messages between first and second data terminals, individual ones of the signaling messages requiring a response from the receiving terminal, said apparatus comprising
at the first data terminal, means, responsive to the input of a signaling message requiring a response message, for repeatedly transmitting the signaling message and repeating such transmission until said response message is received from a second receiving terminal, at the second data terminal, means, responsive to receipt of the signaling message, for repeatedly transmitting the response message until a confirmation message is received from the first data terminal, and at the first data terminal, means for transmitting said confirmation message responsive to receipt of each response message.
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2. Apparatus to control the exchange of signaling messages between data terminals, individual ones of the signaling messages requiring a response from a receiving terminal and other ones of the signaling messages requiring a confirmation from the receiving terminal, said apparatus comprising
means, operative at one of the data terminals and responsive to receipt of a signaling message from the other one of the data terminals, for repeating the transmission of the response until a confirmation message is received from the other one of the data terminals, and means, operative at the other one of the data terminals, for transmitting a confirmation message responsive to receipt of each said response message.
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3. A method of controlling a hand-shake procedure between first and second communications terminals, said method comprising the steps of
at the first communications terminal, transmitting an initial hand-shake message to the second communications terminal and repeating the transmission of the initial hand-shake message until a message responding to the initial hand-shake message is received from the second communications terminal, and transmitting a confirmation message responsive to receipt of each such responding message, and at the second communications terminal, transmitting a response message responsive to receipt of each initial hand-shake message and terminating such transmission upon receipt of said confirmation message.
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4. A method of controlling a hand-shake procedure between first and second communications terminals comprising the steps of
at the first communications terminal, repeatedly transmitting a signaling message to the second communications terminal until a message confirming receipt of the signaling message is received from the second communications terminal, said repeated transmission of said signaling message being independent of an expiration of a timer function associated with waiting for an acknowledgment from said second communications terminal, and responsive to receipt of each signaling message at the second communications terminal, transmitting the confirmation message.
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5. A method of controlling the exchange of signaling messages between first and second data terminals, individual ones of the signaling messages requiring a response from the receiving terminal, said method comprising the steps of
at the first data terminal, responsive to the input of a signaling message requiring a response message, transmitting the signaling message to said second terminal, said signaling message being associated with a predetermined level of priority, and at said first terminal, responsive to receipt of a signaling message associated with said predetermined level of priority from said second terminal prior to receipt of a valid response to said transmitted signaling message, entering a state indicative of receiving a valid response to said transmitted signaling message.
Specification