Method and apparatus for management of network communications

• US 8,972,556 B2
• Filed: 05/07/2012
• Issued: 03/03/2015
• Est. Priority Date: 05/06/2011
• Status: Active Grant

• Current Assignee: Semtech Corporation
• Original Assignee: Sierra Wireless Incorporated
• Inventors: Kavanaugh, Richard Thomas, Vos, Gustav Gerald, Daskalopoulos, Vasilios V.
• Primary Examiner(s): Chan, Wing F
• Assistant Examiner(s): Thieu, Benjamin M
• Application Number:
  US13/465,219
• Publication Number:
  US 20120284385A1
• Time in Patent Office: 1,030 Days
• Field of Search: 709223-224, 709/228, 709/206, 370/328, 370/310
• US Class Current: 709/223
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 61/2553 Binding renewal aspects, e.g. using keep-alive messages
• CPC Class Codes: H04L 61/256 NAT traversal
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04W 4/50 Service provisioning or reconfiguring
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 76/25 Maintenance of established connections

Abstract

A method and apparatus for maintaining a communication link through a NAT or other boundary device. Keep-alive messages (keep-alives) are transmitted and received by the boundary device to maintain the link therethrough. Address information of a keep-alive purports that keep-alive has traversed or is to traverse a predetermined portion of the communication link, such as a wireless “over the air” portion. However, the keep-alive is inhibited from traversing the predetermined portion. This may be accomplished by one or more of: spoofing the origin of the keep-alive such that it only appears to have traversed the predetermined portion; and causing the keep-alive to be discarded before traversal of the predetermined portion. Discard may be facilitated by configuration of the TTL field of the keep-alive or by use of a filtering device.

Claims

1. A method of maintaining a first communication link between a first communication device and a second communication device, the first communication link established through a boundary device, the method comprising:

a. generating a keep-alive message at a keep-alive server operatively coupled to the boundary device via an auxiliary communication link, the keep-alive server having an IP address which differs from an IP address of the first communication device and an IP address of the second communication device, the keep-alive message being generated having address information indicative that either its origin is the first communication device and its destination is the second communication device or its origin is the second communication device and its destination is the first communication device, wherein said origin is spoofed as originating from either the IP address of the first communication device or the IP address of the second communication device, the address information being further indicative that the second communication device is its source or destination, the address information thereby purporting that the keep-alive message has traversed or is to traverse at least a second predetermined portion of the first communication link coupled to the second communication device and excluding the boundary device;

b. maintaining the first communication link through the boundary device by transmitting the keep-alive message toward the boundary device, wherein the keep-alive message is received by the boundary device, the address information purporting that the keep-alive message has traversed or is to traverse at least a first predetermined portion of the first communication link coupled to the first communication device and excluding the boundary device, the predetermined portion being separate from the auxiliary communication link; and

c. inhibiting the keep-alive message from traversing the first predetermined portion and the second predetermined portion.

2. The method according to claim 1, wherein inhibiting the keep-alive message from traversing the predetermined portion comprises causing the keep-alive message to be discarded before it traverses the predetermined portion.

3. The method according to claim 2, wherein causing the keep-alive message to be discarded before it traverses the predetermined portion comprises configuring a time to live of the keep-alive message, such that the time to live expires after the keep-alive message traverses the boundary device and before the keep-alive message traverses the predetermined portion.

4. The method according to claim 3, wherein the keep-alive packet has as its destination the first communication device, and wherein configuring the time to live (TTL) of the keep-alive message comprises:

notifying the keep-alive server, by the first device, that a prior keep-alive packet was received by the first device; and

shortening the TTL relative to a TTL of the prior keep-alive packet.

5. The method according to claim 2, wherein causing the keep-alive message to be discarded before it traverses the predetermined portion comprises:

marking the keep-alive message with an identifiable characteristic which is unchanged during packet traversal; and

providing a filtering network device along the first communication link excluding the predetermined portion, the filtering network device configured to discard messages marked with the identifiable characteristic and forward messages unmarked by the identifiable characteristic.

6. The method according to claim 1, wherein the keep-alive server and the first communication device are located on a common side of the boundary device, and wherein the keep-alive message is generated so as to have its origin spoofed as originating from the first communication device, thereby achieving said inhibiting of the keep-alive message from traversing the predetermined portion.

7. The method according to claim 1, wherein the keep-alive server and the first device are located on opposite sides of the boundary device.

8. The method according to claim 7, further comprising spoofing the keep-alive message as originating from the second communication device.

9. The method according to claim 7, wherein the keep-alive server is a keep-alive proxy server operatively coupled to the boundary device via the auxiliary communication link, the keep-alive proxy server configured as a proxy server for communication with the second communication device.

10. The method according to claim 1, wherein the predetermined portion of the first communication link is an over-the-air link of a wireless network operated by a mobile network operator.

11. The method according to claim 1, further comprising discovering a length of time for which the boundary device is configured to maintain a pinhole supporting the first communication link, and transmitting successive keep-alive messages at a period less than but proportional to the length of time, and wherein discovering the length of time comprises progressively increasing the period until a pinhole timeout event is encountered due to transmission of a pair of successive keep-alive messages separated by a critical time interval, re-initiating the pinhole, and setting the period as a predetermined portion of the critical time interval.

12. An apparatus for maintaining a first communication link between a first communication device and a second communication device, the first communication link established through a boundary device, the apparatus comprising one or more computing devices and a network interface module and configured to generate and transmit a keep-alive message toward the boundary device via an auxiliary communication link, the apparatus having an IP address which differs from an IP address of the first communication device and an IP address of the second communication device, the keep-alive message comprising address information indicative that either its origin is the first communication device and its destination is the second communication device or its origin is the second communication device and its destination is the first communication device, wherein said origin is spoofed as originating from either the IP address of the first communication device or the IP address of the second communication device, the address information thereby purporting that the keep-alive message has traversed or is to traverse at least a first predetermined portion of the first communication link coupled to the first communication device and excluding the boundary device, the predetermined portion being separate from the auxiliary communication link;

the keep-alive message thereby maintaining the first communication link through the boundary device upon reception by the boundary device, the keep-alive message further configured and transmitted so as to be inhibited from traversing the predetermined portion, the address information being further indicative that the second communication device is its source or destination, the address information thereby purporting that the keep-alive message has traversed or is to traverse at least a second predetermined portion of the first communication link coupled to the second communication device and excluding the boundary device, the apparatus being further configured to inhibit the keep-alive message from traversing the second predetermined portion.

13. The apparatus according to claim 12, wherein inhibiting the keep-alive message from traversing the predetermined portion comprises causing the keep-alive message to be discarded before it traverses the predetermined portion.

14. The apparatus according to claim 13, wherein causing the keep-alive message to be discarded before it traverses the predetermined portion comprises:

marking the keep-alive message with an identifiable characteristic which is unchanged during packet traversal; and

providing a filtering network device along the first communication link excluding the predetermined portion, the filtering network device configured to discard messages marked with the identifiable characteristic and forward messages unmarked by the identifiable characteristic.

15. The apparatus according to claim 12, wherein the apparatus is a keep-alive server configured to spoof the keep-alive message as originating from the first communication device, thereby achieving said inhibiting the keep-alive message from traversing the predetermined portion.

16. The apparatus according to claim 12, wherein the apparatus is a server operatively coupled to the boundary device, the server and the first device located on opposite sides of the boundary device.

17. The apparatus according to claim 16, wherein the server is a keep-alive server configured to spoof the keep-alive message as originating from the second communication device.

18. The apparatus according to claim 16, wherein the server is a keep-alive proxy server operatively coupled to the boundary device via an auxiliary communication link, the keep-alive proxy server configured as a proxy server for communication with the second communication device.

19. The apparatus according to claim 13, wherein causing the keep-alive message to be discarded before it traverses the predetermined portion comprises configuring a time to live of the keep-alive message, such that the time to live expires after the keep-alive message traverses the boundary device and before the keep-alive message traverses the predetermined portion.

20. The apparatus according to claim 12, wherein the predetermined portion of the first communication link is an over-the-air link of a wireless network operated by a mobile network operator.

21. A computer program product comprising a memory having computer readable code embodied therein, for execution by a CPU, for performing a method of maintaining a first communication link between a first communication device and a second communication device, the first communication link established through a boundary device, the method comprising:

a. generating a keep-alive message at a keep-alive server operatively coupled to the boundary device via an auxiliary communication link, the keep-alive server having an IP address which differs from an IP address of the first communication device and an IP address of the second communication device, the keep-alive message being generated having address information indicative that either its origin is the first communication device and its destination is the second communication device or its origin is the second communication device and its destination is the first communication device, wherein said origin is spoofed as originating from either the IP address of the first communication device or the IP address of the second communication device, the address information being further indicative that the second communication device is its source or destination, the address information thereby purporting that the keep-alive message has traversed or is to travetse at least a second predetermined portion of the first communication link coupled to the second communication device and excluding the boundary device,

b. maintaining the first communication link through the boundary device by transmitting a keep-alive message toward the boundary device, wherein the keep-alive message is received by the boundary device, the address information thereby purporting that the keep-alive message has traversed or is to traverse at least a first predetermined portion of the first communication link coupled to the first communication device and excluding the boundary device, the predetermined portion being separate from the auxiliary communication link; and

c. inhibiting the keep-alive message from traversing the first predetermined portion and the second predetermined portion.