Method and system of maintaining a connection in a network communication system

• US 7,978,630 B2
• Filed: 04/30/2009
• Issued: 07/12/2011
• Est. Priority Date: 04/30/2009
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Moliner, Olivier, Bengtsson, Henrik
• Primary Examiner(s): Sheikh; Ayaz R
• Assistant Examiner(s): Wong; Blanche
• Application Number:
  US12/433,088
• Publication Number:
  US 20100278101A1
• Time in Patent Office: 803 Days
• Field of Search: 370/311, 370/254, 455/127.5, 455/574, 455/522
• US Class Current: 370/254
• CPC Class Codes: H04L 61/2553 Binding renewal aspects, e.g. using keep-alive messages
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/145 avoiding end of session, e.g. keep-alive, heartbeats, resumption message or wake-up for inactive or interrupted session
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 76/38 triggered by timers

Abstract

A method and system for maintaining a connection between two hosts in a multi-hop network comprising at least one network node disposed between the two hosts and a network element, e.g., a NAT, designed to release the connection after a period of inactivity. The method includes determining a first node in which a keep-alive message will terminate after crossing a network element designed to release the connection after a period of inactivity, and sending a keep-alive data packet configured to terminate in the first node after crossing the network element designed to release the connection. The keep-alive packet configured to terminate in the first node after crossing the network element designed to release the connection may be sent within a time period less than the time period of inactivity after which the network element would release the connection. The method allows for a connection to be kept open without waking up a client device and/or without activating air interface procedures.

Claims

1. A method for maintaining a connection between a first host and a second host in a multi-hop network having a network element configured to release the connection after a certain time period of inactivity, an air interface, and at least one node, wherein the network element and the at least one node are disposed between the first host and the second host and the air interface is disposed between the network element and the second host, the method comprising:

determining a first node in which a keep-alive data packet will terminate after crossing the network element configured to release the connection after a certain time period of inactivity; and

sending a keep-alive data packet from the first host toward the second host, wherein the keep-alive data packet is configured to terminate in the first node after crossing the network element configured to release the connection,

wherein the step of determining the first node in which the keep-alive data packet will terminate after crossing the network element configured to release the connection after a period of inactivity comprises;

sending a first message to the second host, the first message having a time-to-live (TTL) value at least equal to the number of hops required to send a data packet from the first host to the second host;

providing a keep-alive data packet having a decremented TTL value, the decremented TTL value being less than the number of hops (H) in the network;

sending a message with the decremented TTL value toward the second host;

sending a second message to the second host, the second message having a TTL value at least equal to the number of hops required to send a data packet from the first host to the second host; and

determining if the second message reached the second host,

wherein upon a determination that the second message sent to the second host did not reach the second host, the first host determines the TTL value (TTL_NAT) for the last message to cross the network element configured to release the connection after a period of inactivity;

the second host reconnects to the first host, and the first host sends a keep-alive data packet toward the second host having a TTL value of TTL_NAT, wherein the keep-alive data packet having a TTL value of TTL_NAT is sent at a time interval that is less than the time period of inactivity for which the connection would be released, and wherein the keep-alive data packet having a TTL value of TTL_NAT crosses the network element configured to release the connection but does not cross the air interface.

2. The method of claim 1, wherein the network element configured to release the connection is integrated with a node in the network.

3. The method of claim 2, wherein the keep-alive data packet configured to terminate in the first node after crossing the network element configured to release the connection terminates in the node having the network element integrated therewith.

4. The method of claim 1, wherein the step of sending the keep-alive packet configured to terminate in the node after crossing the network element configured to release the connection after a certain period of inactivity is repeated at a time interval that is less than the time period of inactivity for which the connection would be released.

5. The method of claim 1, wherein the steps of providing a keep-alive data packet with a decremented TTL value, sending a message with the decremented TTL value, and sending a second message with a TTL value at least equal to the number of hops in the network is repeated if the first host determines that the second host received the second message.

6. The method of claim 1, wherein the first host is a server.

7. The method of claim 1, wherein the second host is a mobile client device.

8. The method of claim 1, wherein the connection is a TCP connection.

9. The method of claim 1, wherein the network element configured to release the connection after a certain period of inactivity is a network address translator.

10. A first host comprising:

at least one processor;

at least one transmitter device coupled to the processor, the transmitter operative to transmit and receive information between the first host and a second host upon a network connection being established between the first host and the second host, the network including the first host, the second host, a network element configured to release the connection after a certain time period of inactivity and at least one node, and an air interface, wherein the network element and the at least one node are disposed between the first host and the second host and the air interface is disposed between the network element and the second host; and

the first host is operative to maintain a connection between the first host and the second host by executing logic to;

determine a first node in the network in which a keep-alive data packet will terminate after crossing the network element configured to release the connection after a certain time period of inactivity; and

send a keep-alive data packet from the first host toward the second host, wherein the keep-alive data packet is configured to terminate in the node after crossing the network element configured to release the connection after a certain period of inactivity,

wherein the first host determines the first node in which a keep-alive data packet will terminate after crossing the network element configured to release the connection by executing logic to;

send a first message to the second host, the first message having a time-to-live (TTL) value at least equal to the number of hops required to send a data packet from the first host to the second host;

provide a keep-alive data packet having a decremented TTL value, the decremented TTL value being less than the number of hops (H) in the network;

send a message with the decremented TTL value toward the second host;

send a second message to the second host, the second message having a TTL value at least equal to the number of hops required to send a data packet from the first host to the second host; and

determine if the second message reached the second host,

wherein, upon a determination that the second message sent to the second host did not reach the second host the first host determines the TTL value (TTL_NAT) for the last message to cross the network element configured to release the connection after a period of inactivity;

the second host reconnects to the first host, and the first host sends a keep-alive data packet toward the second host having a TTL value of TTL_NAT, wherein the keep-alive packet having TTL value of TTL_NAT is sent at a time interval less than the time period of inactivity for which the connection would be released, and wherein the keep-alive data packet having a TTL value of TTL_NAT crosses the network element configured to release the connection but does not cross the air interface.

11. A communication system comprising:

a first host with a connection to a second host;

at least one node through which the connection between the first and the second host passes;

a network element configured to release the connection between the first and second host after a certain time period of inactivity, the network element disposed between the first host and the second host; and

an air interface disposed between the network element and the second host;

wherein the first host executes logic to (i) determine a first node in which a keep-alive data packet will terminate after crossing the network element configured to release the connection after a certain time period of inactivity, and (ii) send a keep-alive data packet from the first host toward the second host, wherein the keep-alive data packet is configured to terminate in the first node after crossing the network element configured to release the connection,

wherein the first host determines the first node in which a keep-alive data packet will terminate after crossing the network element configured to release the connection by executing logic to;

send a first message to the second host, the first message having a time-to-live (TTL) value at least equal to the number of hops required to send a data packet from the first host to the second host;

provide a keep-alive data packet having a decremented TTL value, the decremented TTL value being less than the number of hops (H) in the network;

send a message with the decremented TTL value toward the second host;

send a second message to the second host, the second message having a TTL value at least equal to the number of hops required to send a data packet from the first host to the second host; and

determine if the second message reached the second host, wherein, upon a determination that the second message sent to the second host did not reach the second host the first host determines the TTL value (TTL_NAT) for the last message to cross the network element configured to release the connection after a period of inactivity;

the second host reconnects to the first host, and the first host sends a keep-alive data packet toward the second host having a TTL value of TTL_NAT, wherein the keep-alive packet having TTL value of TTL_NAT is sent at a time interval less than the time period of inactivity for which the connection would be released, and wherein the keep-alive data packet having a TTL value of TTL _NAT crosses the network element configured to release the connection but does not cross the air interface.

12. The communication system of claim 11, wherein the network element configured to release the connection is integrated with a node in the network, and the node with which the network element is integrated is disposed in a position preceding an air interface with respect to messages sent from the first host toward the second host.