JP2006352444A - System and method for packet transfer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve effective use of resources on a network, and also to improve operability, as to a system and a method for packet transfer. <P>SOLUTION: The system and the method for packet transfer include: lower nodes (SGSN#a, SGSN#b) connected to terminals (MS#a, MS#b) through the network (wireless access network) 3; and higher nodes (GGSN#a, GGSN#b) connected to the lower nodes through a core network 2, and transfer packets between the terminals. Each higher node is provided with a tunnel setting means 12 for setting and designating a tunnel for transferring packets on the basis of destination addresses of the packets transferred from the terminals through the lower nodes, and each lower node is provided with a packet transfer means 12 for transferring the packets from the terminals to tunnels set according to setting indications from tunnel setting means 12 on the basis of the destination addresses of the packets from the terminals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a packet transfer system and a packet transfer method for setting an optimum route and transferring a packet.

  Currently, third-generation mobile communication services (IMT-2000; International Mobile Telecommunication 2000) are being provided by domestic and foreign mobile telecommunications carriers. The IMT-2000 network in this third generation mobile communication service provides an access line between a mobile terminal (MS) and an Internet service provider (ISP), and the access circuit. Packets such as IP can be transferred on the line. The packet transfer method on the IMT-2000 network is disclosed in the specification TS 23.060 issued by 3GPP (3rd Generation Partnership Project) of the forum that develops a wide range of specifications from services to protocols related to IMT-2000. Yes.

  As shown in this specification, the packet transfer service in IMT-2000 is a SGSN (Serving Packet Radio Service (SUPPORT GP) Support Node) subordinate node in the IMT-2000 network and GGSN. An upper node called (Gateway GPRS Support Node) is installed. The lower node SGSN is installed corresponding to a specific area and has a function of performing processing (location registration process and connection process) of a mobile terminal located in the area, and the upper node GGSN corresponds to the lower node SGSN. It is an upper node and is installed corresponding to a specific Internet service provider (hereinafter abbreviated as “ISP”), and has a function of connection processing with the ISP.

  When each mobile terminal (hereinafter abbreviated as “MS”) is connected to the ISP, it is connected to the ISP via the route of MS-SGSN-GGSN-ISP. FIG. 9 is a sequence explanatory diagram of MS # a, SGSN # a, and GGSN # a when MS # a under SGSN # a connects to ISP. When MS # a connects to ISP, An Active PDP (Packet Data Protocol) Context Request message is transmitted to the node SGSN # a of the radio access network in which the MS #a is located. This message includes the APN (Access Point Name) of the connection destination ISP requested by MS # a. This APN is used as ISP identification information. When the SGSN # a receives the Active PDP Context Request message, the SGSN # a determines a GGSN # a to be connected based on the APN included therein, and sends a Create PDP Context Request message to the GGSN # a. Send.

  The GGSN # a that has received this message performs a process (for example, IP address issuance) for connecting the MS # a to the ISP, and returns a Create PDP Context Response message to the SGSN # a. SGSN # a returns an Active PDP Context Accept message to MS # a. Thereby, a tunnel capable of performing packet transfer is set between MS # a and SGSN # a and between SGSN # a and GGSN # a, and connection between MS # a and GGSN # a is established. Is completed. Note that the tunnel for performing packet transfer is called a GTP (GPRS Tunneling Protocol) tunnel.

  By the way, in the packet transfer service in the IMT-2000 network, when a certain MS # a and another MS # b communicate with each other, even if both terminals are located nearby, the GGSN or the Communication is performed via the ISP. For example, as shown in FIG. 10, the prior art includes GGSN # a, GGSN # b, SGSN # a, SGSN # b, MS # a, MS # b, ISP1, core network 2, and radio access network 3. In the example packet transfer system, MS # a under the control of a certain SGSN # a (for example, Sapporo) and MS # b under the control of another SGSN # b (for example, Hakodate) communicate with each other. The tunnel T1 between the MS # a and the SGSN # a, the tunnel T2 between the SGSN # a and the ISP compatible GGSN # a (for example, Tokyo), the GGSN # a and the SGSN # b, And a tunnel T4 between the SGSN # b and the MS # b are formed, and packet transfer is performed between the MS # a and the MS # b via the tunnels T1 to T4.

  In this conventional example, for example, even when MS # a and MS # b exist nearby, MS # a-SGSN # a-GGSN # a-ISP-GGSN # b-SGSN # b-MS # The route of b is formed and packet transfer is performed. Therefore, effective use of network resources cannot be achieved, and the end-to-end delay is large.

  Therefore, a packet transfer system shown in the system configuration diagram of FIG. 11 and the sequence diagram of FIG. 12 has been proposed. In this packet transfer system, the location information of the MS # a and MS # b of the radio access network 3 is managed by an HLR (Home Location Register) on the core network 2 side, and the MS # a is active PDP Context Request. When a message is issued, the connection destination information and service are included in the message. The SGSN # a that has received this message determines whether the service type is, for example, external connection or p-to-p (peer-to-peer), and in the case of p-to-p, the connection destination The location inquiry to the HLR is performed as to where the MS is located, and as a location response, for example, when the location is under SGSN #b, the SGSN #a sends a packet to the SGSN #b according to this location response. Is set, and an Active PDP Context Accept message is returned to MS # a. Thereby, the packet transmitted from MS # a does not pass through GGSN # a, but passes through tunnels T1, T5, T4 that form the route of MS # a-SGSN # a-SGSN # b-MS # b. Can be transferred.

When the service type indicates external connection, a Create PDP Context Request message is transmitted from SGSN # a to GGSN # a. Thereby, tunnels T6 and T7 for transferring packets are set between MS # a and SGSN # a and between SGSN # a and GGSN # a (see, for example, Patent Document 1).
JP 2003-338832 A

  In the packet transfer system shown in FIG. 10 of the conventional example, even when the MS exists in a close position, a tunnel for packet transfer via the higher-level GGSN is set, so that the network resource is effective. There is a problem that the utilization cannot be achieved and the end-to-end delay is increased.

  In the packet transfer system shown in FIG. 11 of the conventional example, network resources can be effectively used, but it is necessary to include connection destination information and service information in the connection request message from the MS. Therefore, it is necessary to change the configuration of the MS. Currently, there are many IMT-2000 MSs on the market, and in order to make effective use of network resources, it is necessary to modify all MSs. To achieve this, much time and cost are required. There is a problem that requires. Also, it is not possible to communicate with a server (for example, a mail server or a Web server) on the ISP during communication by setting tunnels T1, T5, T4 between MS # a and MS # b. Even after communication between MS # a and MS # b, MS # a needs to restart from the activation procedure in order to communicate with these servers. Conversely, if you want to communicate with MS # b (VoIP: Voice over IP) while a certain MS is browsing the Web on the ISP, disconnect the ISP and then follow the activation procedure again. Since the process must be executed, there is a problem of lack of operability.

  An object of the present invention is to make effective use of network resources and improve operability by slightly changing the configuration in the network.

  The packet transfer system of the present invention includes a lower node connected to a terminal via a network and an upper node connected to the node via a core network, and transfers the packet between the terminals. In this case, the upper node is provided with tunnel setting means for instructing setting of a tunnel for transferring the packet based on the destination address of the packet transferred from the terminal via the lower node. The packet transfer means for transferring the packet from the terminal to the tunnel set according to the setting instruction from the tunnel setting means based on the destination address of the packet from the terminal is provided.

  The packet forwarding means forwards the packet to the set tunnel when the address table holding the information about the destination address of the packet and the information about the destination address of the packet from the terminal are held. When not held, the packet tunneling processing unit transfers the packet to the upper node.

  Further, the upper node instructs the setting of a tunnel for transferring the packet based on the destination address of the packet transferred from the terminal via the lower node, and holds information regarding the destination address of the packet Tunnel setting means having a table, and address search means for performing destination address search processing for other upper nodes based on the destination address of the packet when the address table does not hold information on the destination address of the packet. It is what you have.

  The packet transfer method of the present invention includes a lower node connected to a terminal via a network and an upper node connected to the node via a core network, and transfers the packet between the terminals. The tunnel setting means provided in the upper node sends a setting instruction of the tunnel for transferring the packet to the lower node based on the destination address of the packet transferred from the terminal via the lower node. And a process for transferring the packet from the terminal to the tunnel set according to the tunnel setting instruction based on the destination address of the packet from the terminal by the packet transfer means provided in the lower node. It is a waste.

  In addition, when the upper node does not hold information on the destination address of the packet in the tunnel setting unit, the upper node relates to the destination address by destination search unit with respect to another upper node holding the information on the destination address. This includes a process of inquiring information, obtaining information on the destination address, and instructing tunnel setting based on the information.

  The configuration of the terminal such as the mobile terminal is the same as the conventional configuration, and the packet transfer means is provided in the lower node and the tunnel setting means is provided in the upper node, so that the lower node can be set without setting the tunnel via the upper node. Since tunnels are set between them and packets are transferred between terminals, and no extra tunnels are set, network resources can be effectively used and packet transfer delay can be shortened. Further, it is possible to transfer a packet between ISPs by transferring a packet between opposite terminals and changing a destination address of the packet. Therefore, operability can be improved.

  The packet transfer system of the present invention will be described with reference to FIG. 1. Lower nodes (SGSN # a, SGSN #) connected to terminals (MS # a, MS # b) via a network (radio access network) 3 are described. b) and upper nodes (GGSN # a, GGSN # b) connected to the lower nodes (SGSN # a, SGSN # b) via the core network 2, and the terminals (MS # a, MS #) b) In a packet transfer system for transferring packets between terminals (GGSN # a, GGSN # b), terminals (MS # a, MS # b) to lower nodes (SGSN # a, SGSN # b) Based on the destination address of the packet transferred via the tunnel, tunnel setting means 12 is provided for instructing setting of a tunnel for transferring the packet, and the lower nodes (SGSN # a, SG N # b) in the tunnel set in accordance with the setting instruction from the tunnel setting means 12 based on the destination address of the packet from the terminal (MS # a, MS # b), the terminal (MS # a, MS # b) The packet transfer means 12 for transferring the packet from is provided.

  The packet transfer method of the present invention also includes a lower node (SGSN # a, SGSN # b) connected to a terminal (MS # a, MS # b) via a network (radio access network) 3, and a lower node (SGSN). #A, SGSN # b) including higher-order nodes (GGSN # a, GGSN # b) connected via the core network 2, and transferring packets between terminals (MS # a, MS # b) In the packet transfer method, the tunnel setting means 12 provided in the upper node (GGSN # a, GGSN # b) causes the terminal (MS # a, MS # b) to the lower node (SGSN # a, SGSN #). b) Based on the destination address of the packet forwarded via b), a tunnel setting instruction for forwarding the packet is sent to the lower nodes (SGSN # a, SGSN # b) And the tunnel setting based on the destination address of the packet from the terminal (MS # a, MS # b) by the packet transfer means 11 provided in the lower node (SGSN # a, SGSN # b). And a process of transferring a packet from the terminal (MS # a, MS # b) to the tunnel set according to the instruction.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, and in an IMT-2000 network, a lower node (SGSN; General Packet Radio Service) Support between a radio access network 3 and a core network 2 Node), an upper node (GGSN; Gateway GPRS Support Node) between the core network 2 and the Internet service provider side network (ISP) 1 side, and a mobile terminal (MS; Mobile Station) on the radio access network 3 side SGSN # a and SGSN # b corresponding to MS # a and MS # b have packet transfer means (SGSN # b side is not shown) 11, and GGSN # a and GGSN # b are Le setting means 12 (GGSN # b side omitted) and has a.

  MS # a and MS # b have the same configuration as the conventional example based on the specification of IMT-2000, and other mobile terminals not shown in the figure are the same as the conventional example based on the specification of IMT-2000. It has the structure of. Moreover, it can be applied not only as a mobile terminal but also as a fixed terminal. T11 is a tunnel between MS # a and SGSN # a, T12 is a tunnel between SGSN # a and GGSN # a, T13 is a tunnel between SGSN # a and SGSN # b, and T14 is SGSN # A tunnel between b and MS # b is shown.

  2 is an explanatory diagram of the main part of the packet transfer means 11 in FIG. 1, in which 21 is a packet type determination unit, 22 is a packet analysis unit, 23 is an address table, 24 is a packet tunneling processing unit, and 25 is control data. A processing unit, 26 is a packet receiving unit, and 27 is a packet transmitting unit. The packet type determination unit 21 determines whether or not the packet received by the packet reception unit 26 is a packet addressed to its own node, and the address table 23 includes the address of the destination MS and the SGSN as illustrated in an enlarged manner. It is a table holding information regarding the destination address of a packet including an address.

  Further, the packet analysis unit 22 extracts the destination address (for example, IP address) of the packet, and determines whether the address table 23 stores information about the destination address (tunnel information of the SGSN address corresponding to the destination). It has a function of referring to and confirming. The packet tunneling processing unit 24 has a function of processing a tunnel (GTP tunnel, IPinIP tunnel, etc.) for transferring a packet based on information from the packet analysis unit 22. The control data processing unit 25 has a function of performing processing of control data addressed to the own node, creation of control data addressed to other nodes, and the like.

  FIG. 3 is an explanatory diagram of the main part of the tunnel setting means 12 in FIG. 1, wherein 31 is a tunnel creation instruction unit, 32 is a packet analysis unit, 33 is an address table, 34 is a packet transfer unit, and 35 is control data processing. , 36 is a packet receiving unit, 37 is a packet transmitting unit, 38 is a packet type determination processing unit, and 39 is a tunneling processing unit. The packet analysis unit 32 and the address table 33 have the same configuration and functions as the packet analysis unit 22 and the address table 23 in the packet transfer unit 11, and the tunnel creation instruction unit 31 is connected to other nodes. It has a function of creating control data for instructing tunnel creation and transferring it to the tunneling processing unit 39 of the packet transfer unit 34.

  Similarly to the control data processing unit 25 in FIG. 2, the control data processing unit 35 has a function of processing control data addressed to its own node, creating control data addressed to other nodes, and the like. . The packet transfer unit 34 includes a packet type determination processing unit 38 and a tunneling processing unit 39, and the packet type determination processing unit 38 is similar to the packet type determination unit 21 in the packet transfer means 11, as in the packet reception unit 36. The tunneling processing unit 39 has a function of determining whether or not the packet received by the packet is addressed to its own node, and the tunneling processing unit 39 is for transferring a packet in the same manner as the packet tunneling processing unit 24 in the packet transfer unit 11. Has a function of processing a tunnel (GTP tunnel, IPinIP tunnel, etc.), has a function of creating a packet according to control data from the tunnel creation instructing unit 31 and transmitting the packet from the packet transmitting unit 37 to another node Is.

  FIG. 4 is a sequence explanatory diagram of Embodiment 1 of the present invention, showing the mobile terminal MS # a, the lower nodes SGSN # a and SGSN # b, and the upper node GGSN # a in FIG. The terminal MS # b is not shown. Since the connection process (Activation) procedure is the same as that of the conventional example, the details of the sequence are not shown, but in brief, the MS # a sends an Active PDP Context Request message, and SGSN # a determines a connection destination GGSN #a based on an APN (Access Point Name) included in the message, and issues a Create PDP Context Request message to the GGSN #a.

  The GGSN # a that has received this message performs processing (for example, IP address issuance) for connecting the MS # a to the ISP, and returns a Create PDP Context Response message to the SGSN # a. SGSN # a returns an Active PDP Context Accept message to MS # a. As a result, GTP (GPRS (General Packet Radio Service) Tunneling Protocol) tunnels T11 and T12 for packet transfer are set between MS # a and SGSN # a and between SGSN # a and GGSN # a. The

By this activation process, the user packet from MS # a is transferred to GGSN # a via SGSN # a. The GGSN # a is received by the packet receiving unit 36 and transferred from the packet transfer unit 33 to the tunnel setting means 12. The tunnel setting means 12 performs the following processing.
(1) The packet analysis unit 32 extracts a destination address.
(2) It is confirmed whether or not the information about the destination address (SGSN address corresponding to the destination) is held in the address table 33.
(3) When the information about the destination address is not held in the address table 33, the packet is transferred as it is to the ISP side.
(4) When the destination address information is held in the address table 33, the tunnel creation instruction unit 31 creates tunnel creation instruction control data, notifies the tunneling processing unit 39 of the packet transfer unit 34, and sends the tunnel creation instruction control data. A packet for creating instructions is formed and transmitted from the packet transmission unit 37 to a node according to the destination address information. For example, when the address of the SGSN # b corresponding to the address of the destination MS # b is held in the address table 33, a packet including a tunnel creation instruction to the SGSN # b is transmitted to the SGSN # a. Become.

  When SGSN # a receives a packet including a tunnel creation instruction for SGSN # b from GGSN # a, SGSN # a transmits a packet including a tunnel T13 creation instruction to SGSN # b. The tunnels T11 to T14 can be created using, for example, a GTP (GPRS Tunneling Protocol) protocol as described in the specification TS 23.060 issued by the above-mentioned 3GPP. Alternatively, “IP Encapsulation with IP” as defined in RFC 2003 of IETF may be used. Next, the SGSN # a that has received the packet from the MS # a performs the following processing in the packet transfer unit 11.

(1) The packet transfer means 11 of SGSN # a extracts the destination address (for example, IP address) of the packet from the packet received by the packet receiving unit 26 by the packet type determining unit 21.
(2) The packet analysis unit 22 checks whether or not the information relating to the extracted destination address (tunnel information of the SGSN address corresponding to the destination) is held in the address table 23. That is, it is determined whether there is partner information.
(3) When there is no destination information, the packet is transferred from SGSN #a to GGSN #a on the ISP side.
(4) When the destination address information is held in the address table 23, that is, when the destination information is present, the destination SNSG #b is connected to the destination SGSN #b by the tunnel between the SGSN #a and the SGSN #b. Forward the packet. The SGSN # b that has received the packet from the SGSN # a transfers the packet to the MS # b (not shown in FIG. 4). The SGSN # b that has received the packet addressed to the MS # a from the MS # b transfers the packet through the tunnel T13 with the SGSN # a by the same processing as described above.

  Therefore, between MS # a and MS # b, mutual packet transfer is not performed via GGSN # a and GGSN # b on the ISP side but via tunnel T13 set between SGSN # a and SGSN # b. Thus, effective use of network resources is possible, and the transfer delay time between MS # a and MS # b can be shortened. Further, in the state where the tunnel T13 between SGSN # a and SGSN # b is set, the packet from MS # a is not addressed to MS # b, but is stored in the address table 23 of the packet transfer means 11 of SGSN # a. When the destination address of the packet is not registered, the packet transfer unit 11 of SGSN # a transfers the packet to GGSN # a. That is, packets to different destinations can be transmitted without retuning the tunnel. Therefore, operability can be improved. Since a plurality of tunnels can be set, multi-communication is possible.

  FIG. 5 is an explanatory diagram of the second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same names, and MS # a has moved from SGSN # a to SGSN # a1 as indicated by an arrow. Show the case. As in the first embodiment, SGSN # a1, SGSN # a, and SGSN # b have packet transfer means 11 (not shown for SGSN # b), and GGSN # a and GGSN. #B has tunnel setting means 12 (illustration omitted for GGSN # b). The packet transfer unit 11 and the tunnel setting unit 12 have the configuration shown in FIGS. 3 and 4 described above.

  FIG. 6 is a sequence explanatory diagram of Embodiment 2 of the present invention, showing MS # a, SGSN # a1, SGSN # a, GGSN # a, and SGSN # b in FIG. 5 before MS # a moves. Is under the control of SGSN # a, and the activation process is the same as the conventional example shown in FIG. 9 and the process of (Activation) in FIG. 4, and the user packet from MS # a to MS # b is , SGSN # a through SGSN # b. When an MS moves under the control of another SGSN, it is generally used to indicate that the location has changed using the Routing Area Update procedure disclosed in TS 23.0606.9.1.1.2.2. Notify the side.

During or after this Routing Area Update procedure, SGSN #a notifies SGSN #b that accommodates the communication partner terminal that MS #a has moved (Inter-SGSN RA (Routing Area). ) Update), perform the following procedure to change the tunnel.
(1) The SGSN # a that accommodates the MS # a before moving confirms whether or not the SGSN # a owns information (such as an SGSN address corresponding to the destination) regarding the destination address for the MS # a.
(2) When the destination address information is held, the SGSN # a notifies the SGSN # b that the MS # a has moved under the control of the SGSN # a1.
(3) SGSN # b notifies tunnel creation to SGSN # a1. SGSN # a1 creates a tunnel between SGSN # a1 and SGSN # b.
Next, the SGSN # a1 that has received the packet from the MS # a uses the packet transfer unit 11 to extract the destination address and determine whether or not to hold the destination information with reference to the address table. If yes, forward to SGSN # b. Therefore, in the case of a change in area due to movement of MS # a, the setting of the tunnel before movement for SGSN # b can be changed between SGSN # a1 and SGSN # b after movement.

  FIG. 7 is an explanatory diagram of Embodiment 3 of the present invention. The same reference numerals as those in FIG. The destination search means 13 is not shown on the GGSN # b side. Similarly, the packet transfer means 11 and the tunnel setting means 12 have the configuration shown in FIGS. 2 and 3, and SGSN # b, Illustration of the GGSN # b side is omitted.

  FIG. 8 is a sequence explanatory diagram of Embodiment 3 of the present invention, showing MS # a, SGSN # a, GGSN # a, GGSN # b, and SGSN # b. The activation process is the same as the conventional example shown in FIG. Similar to the (Activation) process in FIG. 4, the user packet from the MS # a is transferred to the GGSN # a via the SGSN # a. In this case, the tunnel setting unit 12 of the GGSN #a extracts the destination address and confirms whether or not the information regarding the destination address (such as the SGSN address corresponding to the destination) is held. In the third embodiment, even when the information about the destination address is not held, the information about the destination address held in the other GGSN is obtained by the destination search means 13 to enable packet transfer. Is.

  The activation process is the same as the conventional example shown in FIG. 9 and the (Activation) process in FIG. 4, and the user packet from MS # a to MS # b is transferred from SGSN # a to SGSN # b. Is done. The destination address is extracted by the tunnel setting means in the GGSN #a, and it is determined whether or not the information regarding the destination address is held. If so, the tunnel creation instruction is given to the SGSN #a. Accordingly, SGSN # a issues a tunnel creation instruction to SGSN # b. In this case, a packet transfer route between MS # a and MS # b is set by the same processing as in the case shown in FIG.

If GGSN # a does not have information regarding the destination address, the destination search means 13 performs the following processing.
(1) In GGSN # a, address information of the GGSN corresponding to the destination address is searched from the destination address (for example, IP address) information of the packet. (Generally, since the IP address of the terminal is assigned by the GGSN, each GGSN knows its own address and the address of the MS under its control. Therefore, the GGSN shares the GGSN address and the network prefix issued by the GGSN. By doing so, the address of the GGSN corresponding to the destination address can be obtained).
(2) When there is no GGSN corresponding to the destination address, the packet is transferred to the ISP side as it is.

(3) When there is a GGSN corresponding to the destination address, it is confirmed whether or not the GGSN (GGSN # b in the figure) has information about the destination address (such as an SGSN address corresponding to the destination). To do.
(4) GGSN # b searches and confirms whether or not it owns information about the destination address (such as an SGSN address corresponding to the destination), and the result (whether it is held or not) In this case, SGSN # b address) is returned to GGSN # a.
(5) The GGSN # a that has received the result of the inquiry to the GGSN # b transfers the packet as it is to the ISP side when information on the destination address (that is, the address of the corresponding SGSN # b) cannot be obtained.
(6) When GGSN # a can obtain the destination address information (that is, the address of the corresponding SGSN # b), GGSN # a instructs tunnel creation (with SGSN # b) to SGSN # a. .

  Although each of the above-described embodiments has been described by taking the IMT-2000 network as an example, the present invention can be similarly applied to any mobile communication network that provides an access line with an IP network. Even if it is not a mobile communication network, generally, a network that provides an access line with an IP network is a network that is composed of a plurality of layers (such as a lower node SGSN and an upper node GGSN). It is also possible to apply the embodiments. That is, the present invention can be applied to a network configuration including a fixed terminal.

It is explanatory drawing of Example 1 of this invention. It is explanatory drawing of a packet transfer means. It is explanatory drawing of a tunnel setting means. It is sequence explanatory drawing of Example 1 of this invention. It is explanatory drawing of Example 2 of this invention. It is sequence explanatory drawing of Example 2 of this invention. It is explanatory drawing of Example 3 of this invention. It is sequence explanatory drawing of Example 3 of this invention. It is sequence explanatory drawing of a prior art example. It is explanatory drawing of the tunnel setting of a prior art example. It is explanatory drawing of the tunnel setting of a prior art example. It is sequence explanatory drawing of a prior art example.

Explanation of symbols

1 Internet service provider side network (ISP)
2 Core network 3 Radio access network 11 Packet transfer means 12 Tunnel setting means MS # a, MS # b Mobile terminal SGSN # a, SGSN # b Lower node GGSN # a, GGSN # b Upper node T11 to T14 Tunnel

Claims (5)

In a packet transfer system that includes a lower node connected to a terminal via a network and an upper node connected to the node via a core network, and transfers packets between the terminals,
The upper node is provided with tunnel setting means for instructing setting of a tunnel for transferring the packet based on the destination address of the packet transferred from the terminal via the lower node,
A packet transfer means for transferring a packet from the terminal to a tunnel set in accordance with a setting instruction from the tunnel setting means based on a destination address of the packet from the terminal is provided in the lower node. Transfer system.   The packet forwarding means forwards the packet to the set tunnel when the address table holding information about the destination address of the packet and the information about the destination address of the packet from the terminal are held, 2. The packet transfer system according to claim 1, further comprising: a packet tunneling processing unit that transfers the packet to the upper node when the packet is not held.   The upper node, based on the destination address of the packet transferred from the terminal via the lower node, issues an instruction for setting a tunnel for transferring the packet, and holds information about the destination address of the packet Tunnel setting means having address setting means for performing destination address search processing for other upper nodes based on the destination address of the packet when the information about the destination address of the packet is not held in the address table. The packet transfer system according to claim 1. In a packet transfer method for transferring a packet between terminals, including a lower node connected to a terminal via a network and an upper node connected to the node via a core network,
A process of sending a setting instruction of a tunnel for transferring the packet to the lower node based on a destination address of the packet transferred from the terminal via the lower node by the tunnel setting means provided in the upper node; ,
A process of transferring a packet from the terminal to a tunnel set according to the tunnel setting instruction based on a destination address of the packet from the terminal by a packet transfer means provided in the lower node. Packet transfer method.   When the upper node does not hold information on the destination address of the packet in the tunnel setting unit, information on the destination address is sent to another upper node holding the information on the destination address by destination search unit. 5. The packet transfer method according to claim 4, further comprising: obtaining information on the destination address and instructing tunnel setting based on the information.

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