Method of encoding a data packet

• US 6,980,567 B1
• Filed: 05/10/2001
• Issued: 12/27/2005
• Est. Priority Date: 05/10/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Systems, Inc.
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Cohen, Earl T., Uzun, Necdet, Markevitch, James A.
• Primary Examiner(s): Phan, Man U.
• Application Number:
  US09/853,834
• Time in Patent Office: 1,692 Days
• Field of Search: 370231-252, 370349-351, 370389-476, 370/522, 370/535, 375/222, 375/240, 375/262, 375/295, 375/341, 375/345, 714748-752, 714/795, 714/701, 709242-245
• US Class Current: 370/474
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 2212/00 Encapsulation of packets

Abstract

The invention provides a method of encoding a data packet for encapsulation in one or more frames for communication from a transmitter to a receiver in a network interface. The method includes dividing the data packet into one or more data chunks and determining the length of a data chunk as the lesser of the number of bytes available in a current frame, the number of bytes remaining in the data packet, or a predetermined number of bytes. The method includes determining if the data chunk is the end-of-the-packet (EOP) and when the data chunk is not the EOP, the method includes prepending the data chunk with a control character representing the length of the data chunk and non-EOP.

Claims

1. A method of encoding a data packet for encapsulation in one or more frames for communication from a transmitter to a receiver in a network interface, comprising:

dividing the data packet into one or more data chunks;

determining the length of a data chunk as the lesser of the number of bytes available in a current frame, the number of bytes remaining in the data packet, or a predetermined number of bytes;

determining if the data chunk is the end-of-the-packet (EOP); and

when the data chunk is not the EOP, prepending the data chunk with a control character representing the length of the data chunk and non-EOP prior to insertion of the data chunk into a current frame.

2. The method of claim 1, further comprising:

when the data chunk is the EOP, determining if there is an error in communication of the plurality of data chunks; and

when there is not an error in communication of the plurality of data chunks, prepending the data chunk with a control character representing the length of the data chunk and EOP.

3. The method of claim 2, further comprising:

when there is an error in communication of the plurality of data chunks, prepending the data chunk with a control character representing the length of the data chunk, EOP, and error in communication (ERR).

4. The method of claim 1, further comprising:

determining the number of bytes remaining in the current frame; and

when the number of bytes remaining in the current frame is equal to one, inserting a pad character to the current frame.

5. The method of claim 4, further comprising:

when the number of bytes remaining in the current frame is not equal to one, inserting a data chunk into the current frame.

6. The method of claim 1, further comprising:

determining if there is a gap in the data packet; and

when there is a gap in the data packet, inserting one or more characters represent pad in the current frame.

7. The method of claim 1, further comprising:

determining if there is a mode change in the communication of the one or more frames; and

when there is a mode change,

determining if the number of bytes remaining in the current frame is less than a second predetermined number, and

when the number of bytes remaining in the current frame is not less than the second predetermined number, inserting a control character representing the mode change in the current frame.

8. The method of claim 7, further comprising checking upon a mode change if the frame should be truncated, and if so, truncating the frame so the mode change information is immediately transmitted to the receiver.

9. The method of claim 8, further comprising truncating the frame while maintaining alignment in the network interface.

10. The method of claim 1, further comprising:

prepending the frame with a control byte representing the beginning-of-frame (BOF).

11. The method of claim 10, wherein the control byte representing BOF indicates mode of transmission and depth information for a complementary receiver on a same side of the network interface.

12. The method of claim 10 further comprising:

prefixing another control byte representing the BOF that is identical to the other control byte representing BOF.