System and method for identifying upper layer protocol message boundaries

• US 7,295,555 B2
• Filed: 08/29/2002
• Issued: 11/13/2007
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Elzur, Uri
• Primary Examiner(s): Orgad; Edan
• Assistant Examiner(s): Wilson; Robert W.
• Application Number:
  US10/230,643
• Publication Number:
  US 20030172342A1
• Time in Patent Office: 1,902 Days
• Field of Search: 370469-476, 709230-231
• US Class Current: 370/394
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

Systems and methods that identify the Upper Layer Protocol (ULP) message boundaries are provided. In one example, a method that identifies ULP message boundaries is provided. The method may include one or more of the following steps: attaching a framing header of a frame to a data payload to form a packet, the framing header being placed immediately after the byte stream transport protocol header, the framing header comprising a length field comprising a length of a framing protocol data unit (PDU); and inserting a marker in the packet, the marker pointing backwards to the framing header and being inserted at a preset interval.

Claims

1. A method for locating a framing header in a received Transmission Control Protocol (TCP) frame, the method comprising:

locating a backwards-pointing marker; and

using information stored in the backwards-pointing marker to locate the framing header,

wherein locating a backwards-pointing marker comprises subtracting an initial value and performing a modulo operation on a TCP sequence number with respect to a preset marker interval.

2. The method according to claim 1 wherein the initial value represents a TCP sequence location of a first TCP payload byte.

3. The method according to claim 1, wherein the information stored in the backwards-pointing marker comprises a delta value indicating a number of bytes before a location of the backwards-pointing marker at which the framing header is located.

4. The method according to claim 1, wherein the marker is protected by at least one of an error detection code and an error correction code carried in a marker field.

5. A method according to claim 1 for locating a framing header in a received Transmission Control Protocol (TCP) frame, the method comprising:

locating a backward-pointing marker;

using information stored in the backwards-pointing marker to locating the framing header;

locating a forwards-pointing marker; and

using information stored in the forwards-pointing marker to locate a second framing header.

6. The method according to claim 5, wherein the information stored in the backwards-pointing marker comprises a delta value indicating a number of bytes before a location of the backwards-pointing marker at which the framing header is located.

7. The method according to claim 5, wherein the marker is protected by at least one of an error detection code and an error correction code carried in a marker field.

8. A method for detecting resegmentation of a Transmission Control Protocol (TCP) segment, the method comprising:

locating a backwards-pointing marker in the TCP segment;

determining a location of a framing header using information stored in the backwards-pointing marker; and

determining that resegmentation of the TCP segment has occurred if the framing header is not at the front of the TCP segment after a TCP header of the TCP segment.

9. A method for detecting resegmentation of a Transmission Control Protocol (TCP) segment, the method comprising:

locating a backwards-pointing marker in the TCP segment;

determining a location of a framing header using information stored in the backwards-pointing marker; and

determining that resegmentation of the TCP segment has occurred if the backwards-pointing marker points to a location outside of the TCP segment.

10. The method according to claim 9, further comprising:

determining that resegmentation of the TCP segment has occurred if the backwards-pointing marker is not fully present in the TCP segment.

11. A method for detecting resegmentation of a Transmission Control Protocol (TCP) segment, the method comprising:

locating a backwards-pointing marker in the TCP segment;

determining a location of a framing header using information stored in the backwards-pointing marker; and

determining that resegmentation of the TCP segment has occurred if a number of payload bytes in the TCP segment is not equal a number indicated by a framing header length field plus a pad and a Cyclic Redundancy Check (CRC) field.

12. A method for detecting resegmentation of a (Transmission Control Protocol TCP segment, the method comprising:

locating a backwards-pointing marker in the TCP segment;

determining a location of a framing header using information stored in the backwards-pointing marker; and

determining that resegmentation of the TCP segment has occurred if a number of payload bytes in the TCP segment is not equal to a sum of all values of a framing header length fields plus pads and Cyclic Redundancy Check (CRC) fields for multiple framing Protocol Data Units (PDUs) placed in a TCP segment.