Concurrent connection testing for computation of NAT timeout period

• US 7,693,084 B2
• Filed: 02/28/2007
• Issued: 04/06/2010
• Est. Priority Date: 02/28/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Herzog, Shai
• Primary Examiner(s): Ahmed; Salman
• Assistant Examiner(s): HAMPTON, TARELL A
• Application Number:
  US11/711,937
• Publication Number:
  US 20080205288A1
• Time in Patent Office: 1,133 Days
• Field of Search: 370/401, 370/241, 370/251, 709/232
• US Class Current: 370/251
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 61/2553 Binding renewal aspects, e.g. using keep-alive messages
• CPC Class Codes: H04L 61/2578 without involvement of the NAT server

Abstract

Concurrent testing of NAT connections using different timeout values to compute a keep-alive value for the NAT device. Computation of the approximate timeout value is accomplished concurrently over multiple test connections within about a time equivalent to the actual NAT timeout value. The architecture validates the computation of the approximate timeout value by distinguishing NAT connection failure from external failure using a control connection. Moreover, computation of the keep-alive value is performed only once for a given NAT device rather than being an on-going process for that NAT device. When one of the test connections fails, it is determined that the NAT timeout value is less than the test timeout value associated with the failed test connection. Accordingly, a smaller test timeout value is then selected as the keep-alive value for keep-alive processing of the NAT device.

Claims

1. A computer-implemented system that facilitates connection management, comprising:

a test component for computing a keep-alive value of an address translation device as part of a test process by concurrently testing multiple connections comprising at least a control connection and one or more test connections through the address translation device, wherein the test component;

generates a set of different test time out values,

sends packets associated with the different test time out values over the control connection and the one or more test connections, and

computes the keep-alive value for the address translation device based on a test time out value associated with a packet received over at least one test connection when a packet associated with a higher test time out value is not received over the at least one test connection; and

a validation component for validating computation of the keep-alive value against an external event, wherein the validation component;

checks whether a packet associated with the higher test time out value was received over the control connection, and

validates the test time out value associated with the packet received over the at least one test connection against the external event if the packet associated with the higher test time out value was received over the control connection.

2. The system of claim 1, wherein the test component performs the test process via a client device of a private network.

3. The system of claim 2, wherein the test component of the client generates a set of progressively larger test timeout values and opens the multiple connections based on the set of test timeout values.

4. The system of claim 1, wherein the address translation device is a network address translation (NAT) device that interfaces a server of a public network to a client of a private network.

5. The system of claim 1, wherein the validation component employs the control connection to eliminate network failure as a factor in the computation of the keep-alive value.

6. The system of claim 1, wherein the test component generates a set of N different test timeout values, where N is a positive integer, and opens N+1 connections comprising N test connections and the control connection as the multiple connections utilized for the test process.

7. The system of claim 1, wherein the multiple test connections are distinct from active data connections of the address translation device.

8. The system of claim 1, wherein the test component injects packets associated with progressively larger test timeout values into corresponding test connections of the multiple connections for communication to a client.

9. The system of claim 8, wherein the test component sends the packets in accordance with an incrementing timer, one of the packets sent over a test connection and one packet sent over the control connection.

10. The system of claim 9, wherein the test component selects a smaller test timeout value as the keep-alive value when the packet associated with the higher test time out value sent over the at least one test connection is not received.

11. The system of claim 1, wherein the multiple test connections facilitate TCP or UDP protocol communications.

12. A computer-implemented method of managing a communications connection, comprising acts of:

opening multiple connections in a NAT device of a communications channel, the multiple connections comprising at least a control connection and one or more test connections;

generating a set of different test timeout values;

sending packets associated with the different test time out values over the control connection and the one or more test connections; and

computing a keep-alive value for the NAT device based on a test time out value associated with a packet received over at least one test connection and non-receipt of a packet associated with a higher test time out value over the at least one test connection;

checking whether a packet associated with the higher test time out value was received over the control connection; and

validating the test time out value associated with the packet received over the at least one test connection if the packet associated with the higher test time out value was received over the control connection.

13. The method of claim 12, further comprising validating operation of the test connections based on receipt of packets over the control connection.

14. The method of claim 12, further comprising applying the keep-alive value to active data connections of the NAT device.

15. The method of claim 12, further comprising concurrently testing over the control connection and the one or more test connections while an active data connection passes native data.

16. The method of claim 12, further comprising increasing a number of the test connections and a corresponding number of test timeout values to provide more precise computation of NAT timeout value.

17. The method of claim 12, further comprising computing the keep-alive value based on a previous keep-alive value to provide a higher resolution keep-alive value relative to a NAT timeout value of the NAT device.

18. The method of claim 12, further comprising automatically determining when to employ multiple iterations using N different test timeout values, where N is a positive integer, or a single iteration with a larger number of test timeout values.

19. The method of claim 12, further comprising selecting a smaller test timeout value from the set of the different test timeout values as the keep-alive value based on the non-receipt of the packet associated with the higher test time out value over the at least one test connection.

20. A computer-implemented system, comprising:

computer-implemented means for opening multiple connections in a NAT device of a communications channel, the multiple connections comprising at least a control connection and one or more test connections;

computer-implemented means for generating a set of progressively larger test timeout values;

computer-implemented means for sending test packets associated with the progressively larger test time out values over the one or more test connections;

computer-implemented means for concurrently sending control packets associated with the progressively larger test time out values over a control connection;

computer-implemented means for computing a keep-alive value for the NAT device based on a test time out value associated with a test packet received over at least one test connection and non-receipt of a test packet associated with a higher test time out value over the at least one test connection;

computer-implemented means for checking whether a control packet associated with the higher test time out value was received over the control connection; and

computer-implemented means for validating the test time out value associated with the test packet received over the at least one test connection if the control packet associated with the higher test time out value was received over the control connection.