Method for inverse multiplexing of ATM using sample prepends

In a digital telecommunication system, a method for communicating asynchronously-transmitted cells of a session over a plurality of parallel links between a source node and a destination node in a preselected order, said method comprising:

• assigning to each said cell in said session a single count value indicative of order;
• transmitting over said parallel links said count value with its corresponding cell as a prepend;
• receiving said cells in any order;
• examining each prepend of each cell to determine order;
• and
• restoring each cell to its preselected order based on a value of its associated prepend, wherein the method further includes the steps, upon a queue read operation, to accommodate a longest delayed cell transit time and a greatest amount that the count of a newly-arrived cell can exceed the value of the queue head, comprising:
• 1. if (T*H) then setting Tcomp=T+Crange+1, otherwise setting Tcomp=T;
• thereafter
• 2. if (T=H), then
• 3. outputting cell at location T (valid or otherwise) and then invalidating queue location without incrementing T;
• 4. else if (cell at location T is valid) OR (Tcomp*H+M) then:
• 5. outputting the cell at location T (valid or otherwise) and then invalidating queue location;
• thereafter
• 6. setting T=T+1;
• then
• 7. if (T>Crange) then set T=0, where H is the location of the head of a queue, T is the location of the tail of the queue and C is count range.

A digital telecommunications system, comprising:

• a plurality of parallel links operable to communicate asynchronously-transmitted cells of a session;
• a first cluster interface operable to perform the steps of:
• assigning each of the cells in the session a single count value indicative of a preselected order;
• and
• transmitting the count value over the parallel links as a prepend to the cells;
• and
• a second cluster interface operable to perform the steps of:
• receiving the cells in any order;
• determining whether a newly arrived cell is younger or older than a queue head location (H), comprising:
• determining a newly arrived cell to be younger than the queue head location if the count value is equal to or ahead of a queue head location and behind or equal to a queue tail location (T);
• and
• determining the newly arrived cell to be older than the queue head location if the count value of the newly arrived cell is ahead of the queue tail location and behind the queue head location;
• if the newly arrived cell is younger than the queue head, resetting the queue head location to be equal to the count value of the newly arrived cell;
• examining the prepends of the cells to determine order;
• and
• restoring each cell to its preselected order based on the count value of its associated prepend.

A method for communicating asynchronous transfer mode cells over parallel links, comprising:

• assigning each cell in a communication session over a plurality of parallel links a single count value indicative of a preselected order;
• transmitting the count value over the parallel links as a prepend to the cells;
• receiving the cells in any order;
• determining whether a newly arrived cell is younger or older than a queue head location (H), comprising:
• determining a newly arrived cell to be younger than the queue head location if the count value is equal to or ahead of a queue head location and behind or equal to a queue tail location (T);
• and
• determining the newly arrived cell to be older than the queue head location if the count value of the newly arrived cell is ahead of the queue tail location and behind the queue head location;
• if the newly arrived cell is younger than the queue head, resetting the queue head location to be equal to the count value of the newly arrived cell;
• examining the prepends of the cells to determine order;
• and
• restoring each cell to its preselected order based on the count value of its associated prepend.

The method of claim 10, further comprising:

• using a margin of value M representing a largest amount that the count of a newly-arrived cell can exceed the queue head value H;
• using the margin value M to determine whether a newly-arrived cell which is ahead of tail T and equal to or behind H+M is younger than the current H indicative of a lost cell;
• and if so,
• resetting T to a value of C+1.

Logic embodied in a computer-readable medium, operable to perform the steps of:

• assigning each cell in a communication session over a plurality of parallel links a single count value indicative of a preselected order;
• transmitting the count value over the parallel links as a prepend to the cells;
• receiving the cells in any order;
• determining whether a newly arrived cell is younger or older than a queue head location (H), comprising:
• determining a newly arrived cell to be younger than the queue head location if the count value is equal to or ahead of a queue head location and behind or equal to a queue tail location (T);
• and
• determining the newly arrived cell to be older than the queue head location if the count value of the newly arrived cell is ahead of the queue tail location and behind the queue head location;
• if the newly arrived cell is younger than the queue head, resetting the queue head location to be equal to the count value of the newly arrived cell;
• examining the prepends of the cells to determine order;
• and
• restoring each cell to its preselected order based on the count value of its associated prepend.

A system, comprising:

• means for assigning each cell in a communication session over a plurality of parallel links a single count value indicative of a preselected order;
• means for transmitting the count value over the parallel links as a prepend to the cells;
• means for receiving the cells in any order;
• means for determining whether a newly arrived cell is younger or older than a queue head location (H), comprising:
• means for determining a newly arrived cell to be younger than the queue head location if the count value is equal to or ahead of a queue head location and behind or equal to a queue tail location (T);
• and
• means for determining the newly arrived cell to be older than the queue head location if the count value of the newly arrived cell is ahead of the queue tail location and behind the queue head location;
• means for resetting the queue head location to be equal to the count value of the newly arrived cell if the newly arrived cell is younger than the queue head;
• means for examining the prepends of the cells to determine order;
• and
• means for restoring each cell to its preselected order based on the count value of its associated prepend.