Disconnected Transport Protocol Connectivity

• US 20090196178A1
• Filed: 01/31/2008
• Published: 08/06/2009
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ramaiah, Anantha, Dommety, Gopal, Stewart, Randall
• Granted Patent: US 7,808,998 B2
• Time in Patent Office: Days
• US Class Current: 370/231
• 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: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

In an embodiment, an existing transport protocol connection though a mobile device is recognized as having entered a state of disconnect. A lowest received sequence number is determined from received messages to be transmitted over a disconnected transport protocol connection. A disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the lowest received sequence number is transmitted. The disconnect acknowledge message with a receive window of zero and a sequence number of one less than the lowest received sequence number is continued to be transmitted until the transport protocol connection exits the disconnect state to a connect state.

Claims

1. A method comprising:

recognizing an existing transport protocol connection though a mobile device has entered a state of disconnect;

determining a lowest received sequence number from received messages to be transmitted over a disconnected transport protocol connection;

transmitting a disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the lowest received sequence number; and

continuing to transmit the disconnect acknowledge message with a receive window of zero and a sequence number of one less than the lowest received sequence number until the transport protocol connection exits the disconnect state to a connect state.

2. The method of claim 1 wherein determining comprises:

receiving a first message to be transmitted over the existing connection, the first message including a received sequence number; and

receiving a second message to be transmitted over the connection, the second message including the same received sequence number, the received sequence number being the lowest received sequence number.

3. The method of claim 1 comprising:

prior to recognizing that a connection has entered a state of disconnect, tracking connection state data for a transport protocol connection through the mobile device.

4. The method of claim 3 comprising:

performing the steps of transmitting and continuing to transmit upon recognizing an existing transport protocol connection though the mobile device has entered a state of disconnect and determining a lowest received sequence number from received messages to be transmitted over the disconnected transport protocol connection.

5. The method of claim 4 comprising:

tracking a current lowest sequence number received in a series of messages to be transmitted over the connection;

wherein transmitting comprises;

transmitting a disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the current lowest sequence number received;

and wherein continuing to transmit comprises;

continuing to transmit the disconnect acknowledge message with a receive window of zero and a sequence number of one less than the current lowest sequence number received until the transport protocol connection exits the disconnect state to a connect state.

6. The method of claim 3 wherein tracking comprises:

prior to recognizing that a connection has entered a state of disconnect, tracking connection state data for a transport protocol connection through the mobile device, connection state data including a sequence number and an identifier of each message to be transmitted over the connection.

7. The method of claim 2 comprising:

prior to receiving the second message, failing to respond to the received first message with an acknowledgement message.

8. The method of claim 2 wherein receiving a second message comprises:

receiving a second message to be transmitted over the connection, the second message being equivalent to the first message, such that the second message includes the same received sequence number and the same data as the first message.

9. The method of claim 1 comprising:

detecting that a source of messages to be transmitted over the disconnected transport protocol connection has entered a persist state upon initial receipt of the disconnect acknowledgement message; and

performing the step of continuing to transmit upon detection of the persist state.

10. The method of claim 1 comprising:

resuming normal communication over the transport protocol connection upon detecting that the connection has re-entered a connection state.

11. A system comprising:

a network interface, capable of connecting with mobile devices;

a memory operable to store instructions and data, the memory in communication with the network interface;

and an execution unit coupled to the memory, the execution unit in communication with the network interface and data stored in the memory, and responsive to instructions stored in the memory;

wherein the memory is encoded with a disconnect state maintenance application, that when executed in the execution unit, provides a disconnect state maintenance process that maintains transport protocol connection state data in a mobile device by performing operations of;

recognizing an existing transport protocol connection though the mobile device has entered a state of disconnect;

determining a lowest received sequence number from received messages to be transmitted over the disconnected transport protocol connection;

transmitting a disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the lowest received sequence number; and

continuing to transmit the disconnect acknowledge message with a receive window of zero and a sequence number of one less than the lowest received sequence number until the transport protocol connection exits the disconnect state to a connect state.

12. The system of claim 11 wherein determining comprises:

receiving a first message to be transmitted over the existing connection, the first message including a received sequence number; and

receiving a second message to be transmitted over the connection, the second message including the same received sequence number, the received sequence number being the lowest received sequence number.

13. The system of claim 11 comprising:

prior to recognizing that a connection has entered a state of disconnect, tracking connection state data for a transport protocol connection through the mobile device.

14. The system of claim 13 comprising:

tracking a current lowest sequence number received in a series of messages to be transmitted over the connection;

wherein transmitting comprises;

transmitting a disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the current lowest sequence number received;

and wherein continuing to transmit comprises;

continuing to transmit the disconnect acknowledge message with a receive window of zero and a sequence number of one less than the current lowest sequence number received until the transport protocol connection exits the disconnect state to a connect state.

15. The system of claim 11 comprising:

detecting that a source of messages to be transmitted over the disconnected transport protocol connection has entered a persist state upon initial receipt of the disconnect acknowledgement message; and

performing the step of continuing to transmit upon detection of the persist state.

16. Logic encoded in one or more tangible media for execution and when executed operable to:

recognizing an existing transport protocol connection though the mobile device has entered a state of disconnect;

determining a lowest received sequence number from received messages to be transmitted over the disconnected transport protocol connection;

transmitting a disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the lowest received sequence number; and

continuing to transmit the disconnect acknowledge message with a receive window of zero and a sequence number of one less than the lowest received sequence number until the transport protocol connection exits the disconnect state to a connect state.

17. The logic of claim 16 wherein determining comprises:

receiving a first message to be transmitted over the existing connection, the first message including a received sequence number; and

for receiving a second message to be transmitted over the connection, the second message including the same received sequence number, the received sequence number being the lowest received sequence number.

18. The logic of claim 16 comprising:

prior to recognizing that a connection has entered a state of disconnect, tracking connection state data for a transport protocol connection through the mobile device.

19. The logic of claim 18 comprising:

tracking a current lowest sequence number received in a series of messages to be transmitted over the connection;

wherein transmitting comprises;

transmitting a disconnect acknowledgement message with a receive window of zero and a sequence number of one less than the current lowest sequence number received;

and wherein continuing to transmit comprises;

continuing to transmit the disconnect acknowledge message with a receive window of zero and a sequence number of one less than the current lowest sequence number received until the transport protocol connection exits the disconnect state to a connect state.

20. The computer program product of claim 16 comprising:

computer program code for detecting that a source of messages to be transmitted over the disconnected transport protocol connection has entered a persist state upon initial receipt of the disconnect acknowledgement message; and

computer program code for performing the step of continuing to transmit upon detection of the persist state.