Granted Patent B1

US 7,145,908 · App. 09/648,996 · Granted Dec 5, 2006

Abstract

Claims (30)

1. A system for reducing jitter in an Inverse Multiplexing over Asynchronous Transfer Mode (IMA) system, comprising:

a cell status subsystem that determines whether a cell is a data cell or an IMA Control Protocol (ICP) cell and whether a cell is a data cell following an ICP cell; and

a cell reader, coupled to said cell status subsystem, that reads said cell if said cell is a data cell and skips said cell if said cell is an ICP cell, said cell reader further reading said ICP cell, discarding said ICP cell, and reading said data cell if said data cell follows said ICP cell, wherein delays resulting from said reading said ICP cell and said discarding said ICP cell are distributed over a number of IMA Data Cell Clock (IDCC) ticks.

2. The system for reducing jitter as recited in claim 1 wherein said IMA system includes a plurality of links and said cell is associated with one of said plurality of links, said cell reader incrementing a link number associated with said IMA system.

3. The system for reducing jitter as recited in claim 1 wherein said cell status subsystem determines whether said cell is a data cell or an ICP cell by comparing a frame offset of said cell to an ICP offset.

4. The system for reducing jitter as recited in claim 3 wherein said cell is an ICP cell if said frame offset is equal to said ICP offset.

5. The system for reducing jitter as recited in claim 1 wherein said cell status subsystem determines whether said cell is a data cell following an ICP cell by comparing a frame offset of said cell to one more than an ICP offset.

6. A method of reducing jitter in an Inverse Multiplexing over Asynchronous Transfer Mode (IMA) system, comprising:

determining whether a cell is a data cell or an IMA Control Protocol (ICP) cell;

reading said cell if said cell is a data cell;

skipping said cell if said cell is an ICP cell;

determining whether a cell is a data cell following an ICP cell;

if said data cell follows said ICP cell:

reading said ICP cell,

discarding said ICP cell, and

reading said data cell; and

distributing delays resulting from said reading said ICP cell and said discarding said ICP cell over a number of IMA Data Cell Clock (IDCC) ticks.

7. The method as recited in claim 6 wherein said IMA system includes a plurality of links and said cell is associated with one of said plurality of links, said method further comprising incrementing a link number associated with said IMA system.

8. The method as recited in claim 6 wherein said determining comprises comparing a frame offset of said cell to an ICP offset.

9. The method as recited in claim 8 wherein said cell is an ICP cell if said frame offset is equal to said ICP offset.

10. The method as recited in claim 6 wherein said determining whether said cell is a data cell following an ICP cell comprises comparing a frame offset of said cell to one more than an ICP offset.

11. An Inverse Multiplexing over Asynchronous Transfer Mode (IMA) system, comprising:

a transmitting IMA device that receives cells from an Asynchronous Transfer Mode (ATM) layer and distributes said cells across a plurality of links;

a receiving IMA device that recombines said cells from each of said plurality of links and provides said cells to said ATM layer, said receiving IMA device, including:

a cell status subsystem that determines whether a cell associated with a particular link is a data cell or an IMA Control Protocol (ICP) cell and whether a cell is a data cell following an ICP cell, and

a cell reader, coupled to said cell status subsystem, that reads said cell if said cell is a data cell and skips said cell if said cell is an ICP cell, said cell reader reading said ICP cell, discarding said ICP cell, and reading said data cell if said data cell follows said ICP cell, wherein delays resulting from said reading said ICP cell and said discarding said ICP cell are distributed over a number of IMA Data Cell Clock (IDCC) ticks.

12. The IMA system as recited in claim 11 wherein said cell reader increments a link number associated with said IMA system, thereby advancing to a next link of said plurality of links.

13. The IMA system as recited in claim 11 wherein said cell status subsystem determines whether said cell is a data cell or an ICP cell by comparing a frame offset of said cell to an ICP offset.

14. The IMA system as recited in claim 13 wherein said cell is an ICP cell if said frame offset is equal to said ICP offset.

15. The IMA system as recited in claim 11 wherein said cell status subsystem determines whether said cell is a data cell following an ICP cell by comparing a frame offset of said cell to one more than an ICP offset.

Assignments (8)