Techniques for Avoiding Collisions Among Communications Packets by Using Shared Transmission Queue

A non-transitory computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to:

• store, on a local node of the data communications network, a current number of turns in a transmitting queue and a current turn based on zero or more data packets received from other nodes on the channel;
• upon determining that there is a first local data packet of at least one local data packet to transmit, obtain a local transmit turn for the local node in the queue based on successfully transmitting the first local data packet by the local node in a time interval following a last turn in the queue, wherein the time interval is less than a maximum time interval value, and a first data link layer header in the first data packet includes queue fields that hold data that indicate the current number of nodes in the transmitting queue, the local transmit turn, and a request for adding the local transmit turn, thereby ending the current turn;
• while there is still a remaining local data packet of the at least one local data packet to transmit and the current turn is equal to the local transmit turn, transmit the remaining local data packet in which the queue fields indicate the current number of turns in the transmitting queue, the current turn, and no request for adding a turn;
• and
• determine that the local data packet was successfully transmitted when a successful acknowledgement control packet that uniquely indicates the local data packet is received.

An apparatus comprising:

• a communications transceiver;
• at least one processor;
• and
• at least one memory including one or more sequences of instructions,
• the at least one memory and the one or more sequences of instructions configured to, with the at least one processor, cause the apparatus to perform at least the following,
• store a current number of turns in a transmitting queue and a current turn based on zero or more data packets received from other nodes on the channel;
• upon determining that there is a first local data packet of at least one local data packet to transmit, obtaining a local transmit turn for the local node in the queue based on successfully transmitting the first local data packet by the local node in a time interval following a last turn in the queue, wherein the time interval is less than a maximum time interval value, and a first data link layer header in the first data packet includes queue fields that hold data that indicate the current number of nodes in the transmitting queue, the local transmit turn, and a request for adding the local transmit turn, thereby ending the current turn;
• while there is still a remaining local data packet of the at least one local data packet to transmit and the current turn is equal to the local transmit turn, transmitting the remaining local data packet in which the queue fields indicate the current number of turns in the transmitting queue, the current turn, and no request for adding a turn;
• and
• determining that the local data packet was successfully transmitted when a successful acknowledgement control packet that uniquely indicates the local data packet is received.

A data structure stored on a non-transitory computer-readable medium, the data structure comprising a communications data packet that comprises a data link header that comprises:

• a first field holding data that indicates a number of turns in a transmitting queue for a shared communications channel;
• a different second field holding data that indicates a current turn within the transmitting queue;
• a different third field holding data that indicates whether a new turn is being requested by a transmitting node;
• and
• a different fourth field holding data that indicates whether the transmitting node is relinquishing an existing turn in the transmitting queue.