Cost reduction of NAT connection state keep-alive

• US 8,023,432 B2
• Filed: 03/12/2007
• Issued: 09/20/2011
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Herzog, Shai
• Primary Examiner(s): Shah; Chirag G
• Assistant Examiner(s): MITCHELL, DANIEL D
• Application Number:
  US11/716,929
• Publication Number:
  US 20080225865A1
• Time in Patent Office: 1,653 Days
• Field of Search: None
• US Class Current: 370/254
• 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 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 92/02 Inter-networking arrangements
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Keep-alive processing for NAT devices and reducing power consumption in wireless clients. A server driven keep-alive mechanism facilitates keep-alive messages to a NAT device currently providing a connection to a mobile client to refresh the NAT state, thereby reducing or eliminating power consumption in a wireless device to respond to the connection with keep-alive packets. In one instance, keep-alive packets are sent to the NAT device to reset the NAT timeout timer, and then to the mobile client. The client responds only when expected keep-alive packets are not received at the client. In another instance, keep-alive packets reset the NAT timer to maintain the connection but are dropped or self-destruct before reaching the mobile client thereby providing the optimum power conservation in the mobile device. Thus, the client is not forced into extra client activity to send or receive wireless data, thereby draining the battery.

Claims

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

establishing an IP connection between an external network and a wireless device of an internal network via a network boundary device;

receiving a keep-alive packet from the external network into the network boundary device;

resetting a connection timer when the keep-alive packet is received;

maintaining the IP connection between the external network and the wireless device via the network boundary device based on receipt of the keep-alive packet only from the external network;

monitoring the IP connection of the network boundary device based on utilization of an enhanced keep-alive packet processing mode;

automatically changing to a standard keep-alive packet processing mode based on reduced quality in connection state; and

utilizing a processor that executes instructions stored in memory to perform the acts of establishing, receiving, resetting, maintaining, monitoring, and automatically changing.

2. The method of claim 1, further comprising receiving a response from the wireless device when the keep-alive packet is not received at the wireless device.

3. The method of claim 1, further comprising computing a time-to-live (TTL) value based on transit time of the keep-alive packet to the network boundary device and setting the TTL value in the keep-alive packet for dropping the packet.

4. The method of claim 1, further comprising configuring the keep-alive packet to include an nTTL value which when processed by the network boundary device terminates the keep-alive packet at the boundary device such that the wireless device does not receive the keep-alive packet.

5. The method of claim 1, further comprising interrogating the network boundary device, which is a NAT router, to determine if the router can handle enhanced keep-alive packet processing that drops the keep-alive packet before reaching the wireless client.

6. The method of claim 1, further comprising managing multiple connections of the boundary device concurrently by receiving keep-alive packets from the external network to maintain state of corresponding connections.

7. A system, comprising:

means for establishing an IP connection between a public network and a mobile client of a private network;

means for sending keep-alive packets to the means for establishing the IP connection;

means for resetting a connection timer when the keep-alive packet is received;

means for maintaining the IP connection between the external network and the mobile client via the means for establishing the IP connection based on receipt of the keep-alive packet only from the means for sending keep-alive packets;

means for monitoring the IP connection based on utilization of an enhanced keep-alive packet processing mode; and

means for automatically changing to a standard keep-alive packet processing mode based on reduced quality in connection state.

8. The system of claim 7, further comprising means for configuring the keep-alive packets to terminate before reaching the mobile client.

9. The system of claim 7, wherein the mobile client sends a negative acknowledgment when the keep-alive packet is not received.