Method to sustain TCP connection

• US 7,715,334 B2
• Filed: 07/28/2008
• Issued: 05/11/2010
• Est. Priority Date: 04/22/1997
• Status: Expired due to Fees

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Harsch, Thomas B.
• Primary Examiner(s): CHO, HONG SOL
• Application Number:
  US12/180,607
• Publication Number:
  US 20090017810A1
• Time in Patent Office: 652 Days
• Field of Search: 370/311, 370/338, 370/349, 370/328, 370/401
• US Class Current: 370/311
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 52/0241 where no transmission is received, e.g. out of range of the transmitter
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/00 Reducing energy consumption in communication networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention relates to network communication systems for managing client/server connections in a wireless environment. In accordance with the invention, a mobile communication unit (i.e., client), deploys keepalive packets at selected times in order to reset a keepidle timer of a server (e.g., host computer). By periodically resetting the keepidle timer a current connection between the mobile communication unit and server can be maintained as long as desired even when the mobile communication unit is in a power suspend mode. When in a power suspend mode, the mobile communication unit can briefly awake long enough to activate its transmitter and send a keepalive packet to the server to maintain the current connection. In this manner, the mobile communication unit can obtain the power savings of being in primarily a power suspend mode, but still prevent the current connection from timing out.

Claims

1. A mobile device for establishing a connection to a device on a network and maintaining the connection by automatically transmitting transparent keepalive packets on the network, the apparatus comprising:

a processor and memory for facilitating the creation and transmission of unsolicited and transparent keepalive packets to the network and storing information received from the network, wherein the frequency of transmission of keepalive packets is determined by the mobile device such that the device does not end the connection, a keepalive packet is transmitted as part of the mobile device entering a reduced power sleep mode and the mobile device automatically wakes up from the sleep mode, transmits a keepalive packet and returns to the sleep mode;

a user interface component connected to the processor for allowing a user to input data for communication to the network;

a display component connected to the processor for presenting the user information stored in the mobile device; and

an RF component connected to the processor for transmitting messages to the network and receiving messages from the network.

2. The apparatus of claim 1, the user interface component further comprises a bar code scanner.

3. The apparatus of claim 1, the memory further comprises an identification code for identifying the mobile device and distinguishing the mobile device from other mobile devices on the network.

4. The apparatus of claim 3, the mobile device includes an identification code in the keepalive packets sent on the network.

5. The apparatus of claim 4, the mobile device includes an error detecting field in the keepalive packets sent on the network.

6. The apparatus of claim 1, the mobile device facilitates registering an identification code with the network.

7. The apparatus of claim 1, the mobile device facilitates transmitting a keepalive packet on the network at a frequency configured on the mobile device.

8. The apparatus of claim 1, the mobile device uses a Transmission Control Protocol (TCP) to communicate with the network.

9. A method for maintaining a connection between a mobile device and a server on a network, the method comprising:

registering an identification code with the network;

establishing a connection with a server on the network;

transmitting an unsolicited and transparent keepalive packet to the server on the network at a frequency, determined by the mobile device, that prevents the server keepidle timer from expiring; and

waking from a reduced power sleep mode to transmit an unsolicited and transparent keepalive packet to the server on a schedule specified by the mobile device such that the server does not end the connection and then returning to the reduced power sleep mode.

10. The method of claim 9, further comprising transmitting a mobile device identity code in the keepalive packet.

11. The method of claim 9, further comprising the mobile device calculating an error detection code and including the error detection code in the keepalive packet.

12. The method of claim 9, further comprising sending a keepalive packet when entering a reduced power sleep mode.

13. A mobile device for establishing a connection to a device on a network and maintaining the connection by automatically transmitting transparent keepalive packets on the network, the apparatus comprising:

means for facilitating the creation and transmission of keepalive packets to the network and storing information received from the network, wherein the keepalive packets comprise a sending sequence field populated with a number whose value is one less than that expected by a host on the network;

means for allowing a user to input data for communication to the network;

means for maintaining the connection while the mobile device is in a reduced power sleep mode;

means for presenting the user information stored in the mobile device; and

means for transmitting messages to the network and receiving messages from the network.

14. The apparatus of claim 13, further comprising means for identifying the mobile device to the network.

15. The apparatus of claim 13, further comprising means for detecting errors in the messages sent by the mobile device on the network.