Network processing using fractional time stamp values

• US 7,352,697 B1
• Filed: 06/23/2004
• Issued: 04/01/2008
• Est. Priority Date: 06/23/2004
• Status: Expired due to Fees

• Current Assignee: Dinochip Incorporated
• Original Assignee: Dinochip Incorporated
• Inventors: Chen, Li-Sheng, Shao, Huadong, Nguyen, Dziem Dinh, Tang, Qian-Yu
• Primary Examiner(s): Ngo; Ricky Q.
• Assistant Examiner(s): Patel; Chandrahas
• Application Number:
  US10/710,172
• Time in Patent Office: 1,378 Days
• Field of Search: 370/230, 370/235, 370/252, 370/253, 370/412, 709/217, 709/231
• US Class Current: 370/230
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps

Abstract

Fractional or fuzzy time stamp values are used during processing network traffic. Handling fractional time stamp values permits scaling down of time stamp values, so that fewer bits, and memory, are needed to store each fractional time stamp value. According to a specific technique, departure times are set based on a quantity X plus Y/Z, where X is an integer, Y is a numerator, and Z is a denominator. The departure times are synchronized with the ideal departure times after (Z*X+Y) time units. A technique is provided to reduce cell delay variation.

Claims

1. A method of allocating a network port comprising:

providing a first connection and a second connection, each capable of connecting to pass data to the network port;

providing a scale-down factor Z;

providing a first time stamp expression for the first connection;

providing a second time stamp expression for the second connection;

scaling down the first time stamp expression using the scale-down factor Z, wherein the first time stamp expression becomes fractional and includes a quantity X plus Y/Z, where X is an integer, Y is a numerator, and Z is a denominator;

scaling down the second time stamp expression using the scale-down factor Z; and

allocating the network port to the first connection for Z time periods having a total of (Z*X+Y) time units.

2. The method of claim 1 wherein the network port is at least one of a DS-3, OC-3, OC-12, or OC-48 port connection.

3. The method of claim 1 wherein at least one of the Z time periods has X time units.

4. The method of claim 1 wherein at least Y of the Z time periods has X time units and one of the Z time periods has (X+Y) time units.

5. The method of claim 1 wherein an ideal time period has X+Y/Z time units, and the ideal time period is a fractional quantity of times.

6. The method of claim 5 wherein the first time stamp expressions synchronize with the ideal time period every (Z*X+Y) time units.

7. The method of claim 5 wherein a maximum cell delay variation will be (Z−

1)*Y/Z.

8. The method of claim 1 wherein the second time stamp expression becomes fractional and includes a quantity M plus N/Z, where M is an integer, N is a numerator, Z is a denominator, M is different from X, and N is different from Y.

9. The method of claim 1 wherein the scale-down factor Z is user selectable and nonzero.

10. The method of claim 1 wherein when Z is greater than 2, and Y is 2 or greater,

one of the Z time periods has X time units, and V of the Z time periods has X+1 time units.

11. The method of claim 1 wherein the second time stamp fraction is not fractional.