Method and system for transferring data to improve responsiveness when sending large data sets

• US 10,320,684 B2
• Filed: 07/17/2017
• Issued: 06/11/2019
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: PME IP Pty., Ltd.
• Original Assignee: PME IP Pty., Ltd.
• Inventors: Stalling, Detlev, Westerhoff, Malte
• Primary Examiner(s): Kamara, Mohamed A
• Application Number:
  US15/652,164
• Publication Number:
  US 20170317934A1
• Time in Patent Office: 694 Days
• CPC Class Codes: H04L 43/0894 Packet rate
• CPC Class Codes: H04L 45/121 by minimising delays
• CPC Class Codes: H04L 45/125 based on throughput or bandwidth
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/127 by using congestion prediction
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

Most of the internet traffic today is carried out via the Transmission Control Protocol (TCP). The main advantage of TCP is that it provides reliable data transfer to the application layer and simplifies programming. The protocol maximizes data throughput but may also lead to noticeable transmission delay in wide area networks (WAN). A client-server based medical image viewing system is disclosed that achieves high data throughput over TCP without impacting responsiveness. Special timestamp messages inserted into the data stream allow the system to detect situations where network latency increases noticeably and to obtain a reliable estimate of sustained transfer bandwidth. The system applies a feedback scheme that avoids network delays by limiting send bandwidth. In addition other parameters, in particular image compression settings, are dynamically adjusted depending on current network quality.

Claims

1. A method comprising:

(a) determining a congestion window comprising;

inserting a first timestamp message into an application level request associated with a first image from a client computer;

transferring the application level request and the first timestamp message to a server;

receiving the first timestamp message at the server, where a first client time is calculated based at least on a time the first timestamp message is received, and calculating a send bandwidth at the server (b_send) in bytes/msec, where the first client time is used to compute b_send;

sending one or more second timestamp messages from the server to the client computer;

receiving the one or more second timestamp messages at the client computer, where a second time (t_i) is calculated based at least on one or more times the one or more second timestamp messages are received;

calculating a read bandwidth (b_read) in bytes/msec, where b_read=C/T, where C (total number of bytes that were sent from server to client)=c_i−

c<sub>i−

1</sub>, is an amount of data that was sent in a time between a last two second timestamp messages (c_i, c<sub>i−

1</sub>), and T=t_i−

t<sub>i−

1</sub>+d_i−

d<sub>i−

1</sub>, where T (server time in msec) is equal to the time elapsed on the server between the last two second timestamp messages (t_i−

t<sub>i−

1</sub>), where d_i and d<sub>i−

1</sub> are client times and t_i−

t<sub>i−

1</sub> are server times in the last two incoming timestamp messages of the one or more second timestamp messages; and

assigning a congestion window equal to b_read when b_send is greater than or equal to 1.3×

b_read; and

(b) using the congestion window to achieve one or both a high data throughput and a low latency.

2. The method of claim 1, further comprising determining a running average of b_read based on a comparison between two or more second times.

3. The method of claim 1, further comprising using a bandwidth limit applied on the server to reduce b_send.

4. The method of claim 3, where the bandwidth limit is computed using a feedback scheme.

5. The method of claim 4, where the feedback scheme uses a pseudo code.

6. The method of claim 5, where the pseudo code includes an expression

7. The method of claim 1, further comprising assigning a congestion window equal to b_read when b_send is greater than or equal to 1.4×

b_read.

8. The method of claim 1, further comprising discarding one or more contributions of outliers to b_read such that b_read does not exceed 2×

b_est.

9. A method comprising:

(a) determining a bandwidth limit comprising;

inserting a first timestamp message into an application level request associated with a first image from a client computer;

transferring the application level request and the first timestamp message to a server;

receiving the first timestamp message at the server, where a first client time is calculated based at least on a time the first timestamp message is received, and calculating a send bandwidth at the server (b_send) in bytes/msec, where the first client time is used to compute b_send;

sending one or more second timestamp messages from the server to the client computer;

receiving the one or more second timestamp messages at the client computer, where one or more second times (t_i) are calculated based at least on the time the one or more second timestamp messages are received;

calculating a read bandwidth (b_read) in bytes/msec, where b_read=C/T, where C (total number of bytes that were sent from server to client)=c_i−

c<sub>i−

1</sub>, is an amount of data that was sent in a time between a last two second timestamp messages (c_i, c<sub>i−

1</sub>), and T=t_i−

t<sub>i−

1</sub>+d_i−

d<sub>i−

1</sub>, where T (server time in msec) is equal to the time elapsed on the server between the last two second timestamp messages (t_i−

t<sub>i−

1</sub>), where d_i and d<sub>i−

1</sub> are client times and t_i−

t<sub>i−

1</sub> are server times in the last two incoming timestamp messages of the one or more second timestamp messages; and

assigning a bandwidth limit equal to sixty (60) percent of b_read when delay (e) exceeds 40 msec; and

(b) using the bandwidth limit to limit b_send to achieve one or both a high data throughput and a low latency.

10. The method of claim 9, further comprising determining a running average of b_read based on a comparison between two or more second times.

11. The method of claim 9, where the bandwidth limit is computed using a feedback scheme.

12. The method of claim 10, where the feedback scheme uses a pseudo code.

13. The method of claim 12, further comprising where the pseudo code includes an expression

14. The method of claim 9, further comprising increasing the bandwidth limit when e is less than 40 msec.

15. The method of claim 9, further comprising increasing the bandwidth limit when the amount of data (c−

c_i) is less than 10 KB.

16. The method of claim 9, further comprising where the bandwidth limit is reduced by less than fifty (50) percent.

17. A method comprising:

(a) determining a bandwidth limit comprising;

inserting a first timestamp message into an application level request associated with a first image from a client computer;

transferring the application level request and the first timestamp message to a server;

receiving the first timestamp message at the server, where a first client time is calculated based at least on a time the first timestamp message is received, and calculating a send bandwidth at the server (b_send) in bytes/msec, where the first client time is used to compute b_send;

sending one or more second timestamp messages from the server to the client computer;

receiving the one or more second timestamp messages at the client computer, where one or more second times (t_i) are calculated based at least on the time the one or more second timestamp messages are received;

calculating a read bandwidth (b_read) in bytes/msec, where b_read=C/T, where C (total number of bytes that were sent from server to client)=c_i−

c<sub>i−

1</sub>, is an amount of data that was sent in a time between a last two second timestamp messages (c_i, c<sub>i−

1</sub>), and T (server time in msec)=t_i−

t<sub>i−

1</sub>+d_i−

d<sub>i−

1</sub>, where d_i and d<sub>i−

1</sub> are client times and t_i−

t<sub>i−

1</sub> are server times in the last two incoming timestamp messages of the one or more second timestamp messages; and

assigning a bandwidth limit equal to sixty (60) percent of b_read when delay (e) exceeds

18. The method of claim 17, further comprising increasing the bandwidth limit when e is less than emax.

19. The method of claim 17, further comprising increasing the bandwidth limit when the amount of data (c−

c_i) is less than 10 KB.

20. The method of claim 17, further comprising where the bandwidth limit is reduced by less than fifty (50) percent.