Sustaining session connections

• US 9,560,086 B2
• Filed: 01/29/2013
• Issued: 01/31/2017
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Undery, James Evan, Markaryan, Mark
• Primary Examiner(s): Serrao, Ranodhi
• Application Number:
  US13/752,554
• Publication Number:
  US 20130144965A1
• Time in Patent Office: 1,463 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 51/04 Real-time or near real-time messaging, e.g. instant messaging [IM]
• CPC Class Codes: H04L 51/23 Reliability checks, e.g. acknowledgments or fault reporting
• CPC Class Codes: H04L 65/1083 In-session procedures
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/145 avoiding end of session, e.g. keep-alive, heartbeats, resumption message or wake-up for inactive or interrupted session
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

In an embodiment, techniques for sustaining session connections are provided. The techniques send heartbeat messages when not sending a message may cause the session connection to close because of a timeout condition. Heartbeat messages are valid transport layer messages that will be ignored by protocols at higher levels of a data communications stack. As an example, the techniques may send a TCP message containing only a carriage return and line feed (“CRLF”) in its payload. Because the TCP layer considers a message containing only a CRLF to be a valid TCP message, intermediary computing devices such as proxy servers may not interpret heartbeat messages as “keep alive” messages, and may sustain session connections.

Claims

1. A method performed by a computing device for sustaining a session connection, comprising:

opening a session with a second computing device using a session initiation protocol, the session having a connection established through a proxy server; and

sending a heartbeat message using a transport layer protocol from the computing device to the second computing device, wherein the session initiation protocol is employed by a higher layer of a data communications stack than the transport layer protocol, and wherein the heartbeat message is a valid message of the transport layer protocol but ignored by the session initiation protocol, and sending the heartbeat message sustains the session connection by causing reset of a message clock of the connection.

2. The method of claim 1, wherein the heartbeat message comprises a carriage return and line feed.

3. The method of claim 1, wherein the heartbeat message is sent prior to expiry of the message clock.

4. The method of claim 3, wherein the message clock measures time elapsed since a previous message was sent or received.

5. The method of claim 1, wherein the heartbeat message is sent in absence of a message of a session initiation protocol.

6. The method of claim 1, wherein, after transferring the heartbeat message from the computing device to the second computing device, the proxy server resets the message clock.

7. The method of claim 1, wherein the second protocol is TCP/IP.

8. The method of claim 1, further comprising sending messages using the session initiation protocol, wherein the messages are segmented by a transport layer into a set of messages of the transport layer protocol.

9. A computer-readable storage device having stored thereon computer-executable instructions which, when executed, cause a computing device to perform a method comprising:

opening a session with a second computing device using a session initiation protocol, the session having a connection established through a proxy server; and

sending a heartbeat message using a transport layer protocol from the computing device to the second computing device, wherein the session initiation protocol is employed by a higher layer of a data communications stack than the transport layer protocol, and wherein the heartbeat message is a valid message of the transport layer protocol but ignored by the session initiation protocol, and sending the heartbeat message sustains the session connection by causing reset of a message clock of the connection.

10. The computer-readable storage device of claim 9, wherein the method further includes sending messages using the session initiation protocol, wherein the messages are segmented by a transport layer into a set of messages of the transport layer protocol.

11. The computer-readable storage device of claim 9, wherein the heartbeat message is sent in absence of a message of a session initiation protocol.

12. A system for sustaining a session connection, comprising:

a processing unit;

a memory communicatively coupled to the processing unit and storing computer-executable instructions which, when executed, cause the system to perform a method comprising;

receiving a message via a session connection with a remote computing device established through a proxy server, the session connection using a session initiation protocol;

determining whether the received message is a heartbeat message, wherein the heartbeat message is a valid message of a transport layer protocol but has no effect on a session initiation protocol; and

wherein the session connection with the remote computing device is maintained by the heartbeat message by causing reset of a message clock of the session connection.

13. The system of claim 12, wherein the heartbeat message comprises white space characters.

14. The system of claim 12, wherein the received message is forwarded to an application using the session initiation protocol when it is not a heartbeat message.

15. A system for sustaining a session connection, comprising:

a processing unit;

a memory communicatively coupled to the processing unit and storing computer-executable instructions which, when executed, cause the system to perform a method comprising;

establishing a session connection with a remote computing device via a proxy server, the session connection using a session initiation protocol;

determining whether a message of the session initiation protocol has been sent within a predetermined amount of time, and, if no message of the session initiation protocol has been sent, transmitting a heartbeat message to the remote computing device that is a valid message of the transport layer protocol but ignored by the session initiation protocol, thereby causing reset of a message clock of the connection.

16. The system of claim 15, wherein the message clock of the connection is maintained at the proxy server.

17. The system of claim 15, wherein the processing unit and memory are included in a computing device.

18. The system of claim 17, wherein the computing device is remote from the proxy server.

19. The system of claim 15, wherein the second component is configured to transmit the heartbeat message in the absence of a message of a session initiation protocol.

20. The system of claim 15, wherein the heartbeat message is sent prior to expiry of a message clock.