Semi reliable transport of multimedia content

• US 8,060,645 B1
• Filed: 05/26/2009
• Issued: 11/15/2011
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Catania, Nicolas
• Primary Examiner(s): Tran; Philip B
• Application Number:
  US12/472,233
• Time in Patent Office: 903 Days
• Field of Search: 709/224, 709/232, 709/234
• US Class Current: 709/234
• CPC Class Codes: H04L 1/1838 for semi-reliable protocols, e.g. for less sensitive applications such as streaming video buffer level management for video bitstream receiver H04N21/44004
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

Transmission Control Protocol (TCP) segments received from a server are processed to result in improved reliability. An embodiment of the method comprises receiving a first TCP segment from a server and placing the first TCP segment in a segment queue, the first TCP segment having a first sequence number. A determination is made as to whether a second TCP segment is missing from the segment queue based at least in part on a first sequence number. Responsive to determining that the second TCP is missing from the segment queue, placing a placeholder for the second TCP segment in the segment queue. The first TCP segment is delivered to an application responsive to the first TCP segment being the next TCP segment in a sequence.

Claims

1. A method for processing Transmission Control Protocol (TCP) segments received from a server, the method comprising:

receiving a first TCP segment from the server and placing in a segment queue the first TCP segment, the first TCP segment having a first sequence number of a sequence;

determining whether a second TCP segment is missing from the segment queue based at least in part on the first sequence number;

responsive to determining that the second TCP segment is missing from the segment queue, placing in the segment queue a placeholder for the second TCP segment;

assigning a deadline delivery time to the placeholder, the deadline delivery time determined based on a cutoff time for delivering the second TCP segment to an application to which the second TCP segment is intended; and

responsive to the second TCP segment not being received from the server by the deadline delivery time, skipping the second TCP segment and moving on to deliver a next TCP segment in the sequence.

2. The method of claim 1, further comprising:

assigning a deadline delivery time to the first TCP segment; and

delivering the first TCP segment to the application at or prior to the deadline delivery time assigned to the first TCP segment being reached.

3. The method of claim 2, further comprising:

determining the deadline delivery time of the first TCP segment based on a timestamp of a Real-time Transport Protocol (RTP) packet included in the first TCP segment.

4. The method of claim 1, wherein determining whether the second TCP segment is missing from the segment queue, comprises:

responsive to determining that a second sequence number associated with the second TCP segment is less than the first sequence number of the first TCP segment and greater than a third sequence number associated with the last TCP segment delivered in the sequence, determining that the second TCP segment is missing.

5. The method of claim 1, further comprising:

responsive to receiving the second TCP segment prior to the deadline delivery time being reached, replacing the placeholder in the segment queue with the second TCP segment.

6. The method of claim 5, further comprising:

delivering the second TCP segment to the application at or prior to the deadline delivery time being reached.

7. The method of claim 1, further comprising:

responsive to receiving the second TCP segment after the deadline delivery time has been reached, dropping the second TCP segment.

8. The method of claim 1, further comprising:

transmitting an acknowledgment message for the first TCP segment.

9. The method of claim 1, wherein the sequence is based on the sequence number associated with each TCP segment received from the server.

10. A computer program product comprising a non-transitory computer readable storage medium having computer program instructions and data embodied thereon for processing Transmission Control Protocol (TCP) segments received from a server, the computer program instructions and data to configure a processor to perform the operations comprising:

receiving a first TCP segment from the server and placing in a segment queue the first TCP segment, the first TCP segment having a first sequence number of a sequence;

determining whether a second TCP segment is missing from the segment queue based at least in part on the first sequence number;

responsive to determining that the second TCP segment is missing from the segment queue, placing in the segment queue a placeholder for the second TCP segment;

assigning a deadline delivery time to the placeholder, the deadline delivery time determined based on a cutoff time for delivering the second TCP segment to an application to which the second TCP segment is intended; and

responsive to the second TCP segment not being received from the server by the deadline delivery time, skipping the second TCP segment and moving on to deliver a next TCP segment in the sequence.

11. The computer program product of claim 10, wherein the computer program instructions and data further configure the processor to perform the operations comprising:

assigning a deadline delivery time to the first TCP segment; and

delivering the first TCP segment to the application at or prior to the deadline delivery time assigned to the first TCP segment being reached.

12. The computer program product of claim 11, wherein the computer program instructions and data further configure the processor to perform the operations comprising:

determining the deadline delivery time of the first TCP segment based on a timestamp of a Real-time Transport Protocol (RTP) packet included in the first TCP segment.

13. The computer program product of claim 10, wherein determining whether the second TCP segment is missing from the segment queue, comprises:

responsive to determining that a second sequence number associated with the second TCP segment is less than the first sequence number of the first TCP segment and greater than a third sequence number associated with the last TCP segment delivered in the sequence, determining that the second TCP segment is missing.

14. The computer program product of claim 10, wherein the computer program instructions and data further configure the processor to perform the operations comprising:

responsive to receiving the second TCP segment prior to the deadline delivery time being reached, replacing the placeholder in the segment queue with the second TCP segment.

15. The computer program product of claim 14, wherein the computer program instructions and data further configure the processor to perform the operations comprising:

delivering the second TCP segment to the application at or prior to the delivery time being reached.

16. The computer program product of claim 10, wherein the computer program instructions and data further configure the processor to perform the operations comprising:

responsive to receiving the second TCP segment after the deadline delivery time has been reached, dropping the second TCP segment.

17. The computer program product of claim 10, wherein the computer program instructions and data further configure the processor to perform the operations comprising:

transmitting an acknowledgment message for the first TCP segment.

18. The computer program product of claim 10, wherein the sequence is based on the sequence number associated with each TCP segment received from the server.

19. A computer system for processing Transmission Control Protocol (TCP) segments received from a server, the system comprising:

a computer processor; and

a non-transitory computer-readable storage medium storing computer program modules adapted to execute on the computer processor, the computer program modules comprising;

a communication module configured to receive a first TCP segment from the server and placing in a segment queue the first TCP segment, the first TCP segment having a first sequence number;

a timing module configured to;

determine whether a second TCP segment is missing from the segment queue based at least in part on the first sequence number;

place in the segment queue a placeholder for the second TCP segment, responsive to determining that the second TCP segment is missing from the segment queue; and

assign a deadline delivery time to the placeholder, the deadline delivery time determined based on a cutoff time for delivering the second TCP segment to an application to which the second TCP segment is intended; and

a delivery module configured to skip the second TCP segment and move on to delivering a next TCP segment in the sequence in response to the second TCP segment not being received from the server by the deadline delivery time.

20. The system of claim 19, wherein the timing module is further configured to assign a deadline delivery time to the first TCP segment and the delivery module is further configured to deliver the first TCP segment to the application at or prior to the first deadline delivery time assigned to the first TCP segment being reached.

21. The system of claim 20, wherein the timing module is further configured to:

determine the deadline delivery time of the first TCP segment based on a timestamp of a Real-time Transport Protocol (RTP) packet included in the first TCP segment.

22. The system of claim 19, wherein the timing module is further configured to:

determine that the second TCP segment is missing from the segment queue, responsive to determining that a second sequence number associated with the second TCP segment is less than the first sequence number of the first TCP segment and greater than a third sequence number associated with the last TCP segment delivered in the sequence.

23. The system of claim 19, wherein the timing module is further configured to:

replace the placeholder in the segment queue with the second TCP segment, responsive to receiving the second TCP segment prior to the deadline delivery time being reached.

24. The system of claim 23, wherein the delivery module is further configured to:

deliver the second TCP segment to the application at or prior to the deadline delivery time being reached.

25. The system of claim 19, wherein the timing module is further configured to:

drop the second TCP segment, responsive to receiving the second TCP segment after the delivery time has been reached.

26. The system of claim 19, further comprising:

an acknowledgment module configured to transmit an acknowledgment message for the first TCP segment.

27. The system of claim 19, wherein the sequence is based on the sequence number associated with each TCP segment received from the server.