Concurrent connection testing for computation of NAT timeout period

• US 20080205288A1
• Filed: 02/28/2007
• Published: 08/28/2008
• Est. Priority Date: 02/28/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Herzog, Shai
• Granted Patent: US 7,693,084 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• 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 by concurrently testing multiple connections of an address translation device as part of a test process; and

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

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 one of the multiple connections as a control connection to eliminate the external event 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 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 a 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 sent over the 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 test connections in a NAT device of a communications channel;

concurrently testing different test timeout values over the test connections; and

computing a keep-alive value based on non-receipt of a packet over one of the test connections.

13. The method of claim 12, further comprising validating operation of the test connections based on one of the test connection being utilized as a 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 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 repeating the acts of concurrently testing and computing based on a previous iteration 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 of the acts of testing and computing 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 of the different test timeout values as the keep-alive value based on the non-receipt of the packet over one of the test connections.

20. A computer-implemented system, comprising:

computer-implemented means for opening multiple test connections in a NAT device of a communications channel;

computer-implemented means for testing progressively larger test timeout values over the test connections;

computer-implemented means for sending a test packet over one of the test connections;

computer-implemented means for concurrently sending the test packet over a control connection; and

computer-implemented means for computing a keep-alive value based on non-receipt of the packet over the one of the test connections.