Scheme for reliable communications via radio and wire networks using transport layer connection

• US 6,272,148 B1
• Filed: 09/22/1998
• Issued: 08/07/2001
• Est. Priority Date: 09/22/1997
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Takagi, Masahiro, Kamagata, Eiji, Kato, Noriyasu
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Pham, Brenda H.
• Application Number:
  US09/158,095
• Time in Patent Office: 1,050 Days
• Field of Search: 370/338, 370/469, 370/315, 370/331, 370/356, 370/355, 370/401, 370/436, 370/439, 455/507, 455/426
• US Class Current: 370/469
• CPC Class Codes: H04L 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/189 Transmission or retransmission of more than one copy of a message
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• 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 69/165 Combined use of TCP and UDP protocols; selection criteria therefor
• CPC Class Codes: H04L 69/169 Special adaptations of TCP, UDP or IP for interworking of IP based networks with other networks protocols for interworking, protocol conversion H04L69/08
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• 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

A highly reliable gateway device for improving the performance of communications utilizing the transport layer connection provided via a radio network, by setting up the transport layer connection between a wire terminal and a radio terminal in a form suitable for an application, or by enabling a control of the transport layer connection according to the radio communication state between the radio terminal and a base station, without changing implementation of the transport layer of a terminal connected to a wire network, is disclosed. The gateway device determines whether or not to carry out a set up of a connection in divided forms according to an information content of a packet that contains a transport layer protocol data unit requesting a set up of the transport layer connection between the radio terminal of the radio network and the wire terminal of the wire network.

Claims

1. A gateway device for relay connecting a radio network and a wire network, comprising:

a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network; and

a control unit for controlling the connection set up unit by determining whether or not to carry out a connection set up by the connection set up unit according to an information content of a packet that contains a transport layer protocol data unit requesting a set up of the transport layer connection between the radio terminal of the radio network and the wire terminal of the wire network.

2. The gateway device of claim 1, wherein the control unit includes a filter unit for determining whether or not to carry out the connection set up by the connection set up unit by receiving the transport layer protocol data unit and referring to at least one of a port identifier indicating a usage of the transport layer connection, a destination address, a source address, and a flow identifier indicating a flow of said packet, which are contained in said packet.

3. The gateway device of claim 1, further comprising:

a transport layer protocol processing unit for carrying out a transport layer protocol processing; and

a filter unit for giving the transport layer protocol data unit to the transport layer protocol processing unit at a time of relaying a network layer protocol data unit between the radio network and the wire network, by referring to at least one of a port identifier, a destination address, a source address, and a flow identifier indicating a flow of the network layer protocol data unit, which are contained in the network layer protocol data unit, when a protocol identifier for indicating a protocol type of the transport layer protocol data unit which is contained the network layer protocol data unit indicates a connection oriented protocol.

4. The gateway device of claim 1, further comprising:

an application layer gateway unit for relaying data in an application layer;

wherein the control unit also determines whether a connection via the application layer gateway unit or a connection via a lower layer than the application layer is to be set up by the connection set up unit, according to the information content of said packet.

5. The gateway device of claim 4, further comprising:

a transport layer protocol processing unit for carrying out a transport layer protocol processing;

an application processing unit for processing applications; and

a filter unit for giving the transport layer protocol data unit to the application processing unit via the transport layer protocol processing unit at a time of relaying a network layer protocol data unit between the radio network and the wire network, by referring to at least one of a protocol identifier indicating a protocol type of the transport layer protocol data unit, a port identifier, a destination address, a source address, and a flow identifier indicating a flow of the network layer protocol data unit, which are contained in the network layer protocol data unit, when the control unit determines that the connection via the application layer gateway unit is to be set up by the connection set up unit.

6. The gateway device of claim 5, wherein the application layer gateway unit contains a cache unit for storing at least a part of data to be relayed.

7. The gateway device of claim 6, wherein the connection set up unit sets up only the first connection or the second connection when all the data to be relayed are stored in the cache unit.

8. A gateway device in a communication network in which a plurality of gateway devices connected to respectively different radio networks are inter-connected through a wire network, the gateway device comprising:

a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network; and

a control unit for shifting a gateway function to another gateway device if the first connection and the second connection are in established states and disconnecting the first connection and the second connection if one of the first connection and the second connection is not in an established state, when one radio terminal moves from a radio service area covered by a base station of one radio network accommodated in said gateway device to another radio service area covered by another base station of another radio network accommodated in said another gateway device.

9. A gateway control method in a communication network in which a plurality of gateway devices connected to respectively different radio networks are inter-connected through a wire network, where each gateway device has a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network, the method comprising the steps of:

controlling a second gateway device from a first gateway device when one radio terminal moves from a radio service area covered by a first base station of one radio network accommodated in the first gateway device to another radio service area covered by a second base station of another radio network accommodated in the second gateway device, such that the second gateway device starts transmission via the second base station to said one radio terminal of transport layer protocol data units that are not yet transmitted, before the first gateway device receives all acknowledgements for transport layer protocol data units already transmitted to said one radio terminal via the first base station; and

shifting a gateway function with respect to said one radio terminal from the first gateway device to the second gateway device.

10. A gateway control method in a communication network in which a plurality of gateway devices connected to respectively different radio networks are inter-connected through a wire network, where each gateway device has a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network, the method comprising the steps of:

controlling a first gateway device when a moving of one radio terminal from a radio service area covered by a first base station of one radio network accommodated in the first gateway device to another radio service area covered by a second base station of another radio network accommodated in a second gateway device is predicted, so as to start transfer to the second gateway device of data which are already transmitted to said one radio terminal by the transport layer protocol but for which acknowledgements from said one radio terminal are not yet received at the first gateway device;

controlling the first gateway device when the moving of said one radio terminal is completed, so as to start transfer of an information regarding the transport layer protocol at the first gateway device to the second gateway device; and

shifting a gateway function with respect to said one radio terminal from the first gateway device to the second gateway device.

11. The method of claim 10, further comprising the step of:

receiving a notification regarding a state of prediction of the moving or a completion of the moving of said one radio terminal, at the first gateway device from one of the first base station, the second base station, and said one radio terminal.

12. The method of claim 10, further comprising the steps of:

registering an identifier of the second gateway device at a shift providing device for carrying out allocation of a network layer address in a moved site network or transfer. of network layer protocol data units with respect to said one radio terminal;

transmitting a request for address allocation or transfer from said one radio terminal to the shift providing device, when said one radio terminal detects a move between networks by receiving network identifiers of respective networks broadcast from the first base station and the second base station; and

predicting the moving of said one radio terminal or detecting a completion of the moving of said one radio terminal by receiving the identifier of the second gateway device along with a response to said request at said one radio terminal.

13. The method of claim 10, further comprising the step of:

predicting the moving of said one radio terminal or detecting a completion of the moving of said one radio terminal by receiving identifiers of respective gateway devices broadcast by the first base station and the second base station.

14. A gateway device for relay connecting a radio network and a wire network, comprising:

a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network; and

a transmission unit for transmitting a transport layer protocol data unit containing a signal for suppressing packet transmission to a correspondent terminal of one radio terminal, when a handoff start signal indicating that said one radio terminal starts operation for handoff from a radio service area covered by a first base station to a radio service area covered by a second base station.

15. A gateway device for relay connecting a radio network and a wire network, comprising:

a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network; and

a control unit for controlling transmission of transport layer protocol data units when one radio terminal moves from a radio service area covered by a first base station to another radio service area covered by a second base station, such that transmission via the second base station to said one radio terminal of transport layer protocol data units that are not yet transmitted is started before receiving all acknowledgements for transport layer protocol data units already transmitted to said one radio terminal via the first base station.

16. A router device, comprising:

a connection unit for connecting the router device with a plurality of gateway devices either directly or via network, each gateway device having a connection set up unit for setting up a transport layer connection between radio terminals of the radio network in divided forms of first and second connections in a transport layer protocol for communications with the radio network, or a transport layer connection between a radio terminal of the radio network and a wire terminal of the wire network in divided forms of a first connection in a transport layer protocol for communication with the radio network and a second connection in a transport layer protocol for communications with the wire network; and

a route set up unit for making a routing setting such that either network layer protocol data units transmitted by one radio terminal or network layer protocol data unit destined to said one radio terminal will be routed to a specific one of said plurality of gateway devices, at a time of starting service with respect to said one radio terminal.

17. The router device of claim 16, wherein the route set up unit makes the routing setting according to an identifier of one gateway device for routing network layer protocol data units transmitted by said one radio terminal which is specified by exchanges between at least one of said plurality of gateway devices and said one radio terminal.

18. A gateway control method in a communication network having two gateway devices capable of relaying transport layer connection between a first terminal and a second terminal, and carrying out a relay of the transport layer connection by selectively using one of the two gateway devices, the method comprising the steps of:

multicasting transport layer protocol data units transmitted from the first terminal by the transport layer connection, to each of the two gateway devices;

multicasting transport layer protocol data units transmitted from a first gateway device among the two gateway devices that is currently playing a role of relaying the transport layer connection, to the first terminal and a second gateway device among the two gateway devices that is currently playing a role of standby, as a response to the first terminal with respect to transport layer protocol data units received from the first terminal, or to the second terminal and the second gateway device, as a relay to the second terminal;

judging presence or absence of a trouble occurrence in the first gateway device according to at least a state of transport layer protocol data unit reception from the first terminal and the first gateway device, at the second gateway device; and

switching roles of the first gateway device and the second gateway device when the judging step judges that a trouble occurred in the first gateway device.