Method for reducing packet data delay variation in an internet protocol network

• US 20030198220A1
• Filed: 04/18/2002
• Published: 10/23/2003
• Est. Priority Date: 04/18/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Mense, Allan T., Gross, Jonathan H.
• Granted Patent: US 6,765,905 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 47/2458 Modification of priorities while in transit

Abstract

Network nodes (10, 15, 20, 25, 30 40) of a communication network (100) determine whether the queue position (56, 57) of a data packet (60) exceeds a threshold (55). Data packets which are placed in a queue that has a depth greater than the threshold, and therefore will experience increased delay at this node, are remarked to a higher priority for expedited handling at the next hop. The next hop network node which handles that data packet will put it in a higher priority queue (51) such that it will experience less delay at the that node. In this way, a negative correlation in node-to-node delay is achieved and overall delay variation is reduced.

Claims

1. In a communication network, a method for minimizing delay associated with hops among a plurality of network nodes, the method comprising the steps of:

receiving a data packet by a first network node;

remarking by the first network node a header of the data packet with a different priority for processing by a second network node; and

queuing the data packet by the first network node.

2. The method as claimed in claim 1, wherein there is further included a step of determining whether a queuing position of the data packet is below a threshold.

3. The method as claimed in claim 2, wherein if the queueing position of the data packet is greater than the threshold, then the step of remarking a priority indicator in the header by the first network node to indicate a next higher priority queue.

4. The method as claimed in claim 1, wherein there is further included a step of iterating the steps of receiving, remarking and queuing for a plurality of traffic classes.

5. The method as claimed in claim 3, wherein if the queueing position is not greater than the threshold, there is further included the step of leaving the priority indicator unchanged.

6. The method as claimed in claim 1, wherein there is further included the steps of:

marking by the first network node the priority indicator in the header with a quality of service classification; and

marking the priority indicator with a differentiated services code point (DSCP) indication, if no quality of service classification is indicated.

7. The method as claimed in claim 1, wherein there is further included the steps of:

dequeuing the data packet; and

transmitting the data packet to the second network node.

8. In a communication network a method for minimizing delay associated with hops among a plurality of network nodes, the method comprising the steps of:

receiving by a second network node a data packet from a first network node;

determining by the second network node whether a priority indicator of a header of the data packet indicates a priority queue change by the first network node; and

remarking the priority indicator to a next lower priority if the priority indicator was changed by the first network node.

9. The method as claimed in claim 8, wherein if the priority indicator was changed by the first network node, there is further included the step of enqueuing the data packet at a higher priority queue prior to remarking the priority indicator by the second network node.

10. The method as claimed in claim 9, wherein there is further included the steps of:

dequeuing the data packet; and

transmitting the data packet to a next network node.

11. The method as claimed in claim 8, wherein if the priority indicator was not changed by the first network node there is further included the step of determining whether a queue position of the data packet is greater than a threshold.

12. The method as claimed in claim 11, wherein if the queue position of the data packet is greater than the threshold, there is further included the step of remarking by the second network node the priority indicator with a next higher priority queue.

13. The method as claimed in claim 12, wherein there is further included a step of enqueuing the data packet in a priority queue associated with the priority indicator prior to the step of remarking.

14. The method as claimed in claim 13, wherein there is further included the steps of:

dequeuing the data packet; and

transmitting the data packet to a next network node.

15. The method as claimed in claim 8, wherein there is further included a step of iterating the steps of receiving, determining and remarking for a plurality of traffic classes.

16. A method for data packet queue management comprising the steps of:

receiving a data packet including a header;

determining one of a plurality of queues in which to place the data packet, the determining based on a quality of service indicator in the header;

if a queue position of the data packet in the one of the plurality of queues is greater than a threshold, remarking a priority indicator in the header with a next higher priority indicator.

17. The method as claimed in claim 16, wherein there is further included a step of enqueuing the data packet based on the quality of service indicator in the header.

18. The method as claimed in claim 17, wherein there is further included the step of determining, at a time after the remarking step, whether the priority indicator has been changed.

19. The method as claimed in claim 18, wherein there is further included a step of enqueuing the data packet in a higher priority queue, if the priority indicator has been changed.

20. The method as claimed in claim 19, wherein after enqueuing the data packet in the next higher priority queue, the priority indicator is set to a standard priority.