JP4189277B2 - Network connection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a network connection method and a connection apparatus for performing communication between a plurality of IP networks by a mobile terminal such as a PC (personal computer), a PDA (personal digital assistant), and a mobile phone.
[0002]
[Prior art]
In general, in order for a terminal to continue communication with another terminal while moving in the network, it is necessary to move in the network within a range where the IP address is not changed. In a normal IP network, when moving to a different network, it is necessary to change the IP address of the terminal in accordance with the destination network, and communication is interrupted.
[0003]
The MobileIP method is being standardized as a method for ensuring the mobility of terminals in an IP network. The Mobile IP system is a technology that enables data transmission without changing the IP address even if a terminal using the IP network is connected to a network other than the network that is normally used.
[0004]
In the Mobile IP system, a network from which a terminal is moved is a home network, and a communication device to which the terminal is connected before the movement is a home agent. The mobile terminal has a home address that does not change regardless of the destination, and a care-of address that changes depending on the destination network. The moved terminal requests the home agent to transfer data addressed to itself.
[0005]
For example, when transmitting data from a transmission source to a mobile terminal, the transmission source transmits data toward the home address of the mobile terminal. Data is routed from the source router to the home agent. The home agent that has received the data adds an IP header addressed to the care-of address to the data and transfers the data to the mobile terminal. The mobile terminal removes the IP header addressed to the care-of address and receives it as data addressed to the home address. Because of this data flow, Mobile IP routing is called triangle routing (triangular route).
[0006]
Since the Mobile IP method is a method of transferring data via a home agent, the amount of data transfer increases. Therefore, the Mobile IP system has been developed on the assumption that the transmission capacity of the backbone network connecting each router and the home agent is large and there are few transmission errors. For this reason, for example, if the Mobile IP method is used for an ad hoc network in which a router has mobility and a mobile terminal and a mobile router communicate wirelessly, for example, there is a problem that a data arrival rate is low and an arrival time is required. End up. Therefore, it is desirable to use a method different from the Mobile IP method in order to perform communication between terminals in a low-speed, low-quality network while ensuring mobility.
[0007]
Conventionally, in addition to the Mobile IP method described above, a technique for enabling communication without resetting an IP address when a terminal moves within a communication network has been considered (for example, patents). Reference 1).
[0008]
On the other hand, in the non-Mobile IP system, when data is transmitted from a transmission source to a mobile terminal, a request for searching for a route is transmitted from the transmission source in order to grasp which route in the network the destination mobile terminal is on. When the mobile terminal receives the route search request, it responds with its own information, and the mobile router on the route forwards the response. The transmission source that receives the response transmits data to the route to the destination. The mobile router on the route transfers the data toward the destination. Finally, the destination mobile terminal receives the data.
[0009]
[Patent Document 1]
JP 2003-18197 A
[0010]
[Problems to be solved by the invention]
Thus, conventionally, mobility is ensured in the Mobile IP network and the non-Mobile IP network in each network. However, as described above, since mobility is ensured by different methods, communication between terminals participating in different types of networks or between terminals via different types of networks has not been possible.
[0011]
The present invention has been made in consideration of the above-described circumstances, and provides a network connection method and a connection device that enable communication between terminals participating in different networks while ensuring mobility. Objective.
[0012]
[Means for Solving the Problems]
In the present invention, a Mobile IP network capable of performing communication even when a terminal moves in the network by the Mobile IP method is used as an upper network, and the terminal can perform communication by the IP method. First and second IP network is a lower network,
The upper network includes first and second communication devices connected to the first and second IP networks, respectively. The upper network and the lower network Each of the first and second IP networks of And function as a terminal conforming to the Mobile IP scheme for the upper network and function as a terminal conforming to the IP scheme for the lower network The first and second routing tables are provided that record the IP addresses of the terminals existing in the lower network. Place the connecting device, The first communication device functions as a home agent of the first IP network, and records data indicating a correspondence relationship between a home address and a care-of address of a terminal existing in the first IP network. Data indicating a correspondence relationship between a home address and a care-of address of a terminal existing in the second IP network, the second communication device functioning as a home agent of the second IP network The first connecting device records the terminal from the routing table in response to a disconnection notification from the terminal existing in the first IP network in the lower network. Delete the IP address Above Second The connection device is connected to the lower network. The terminal existing in the first IP network moves to the second IP network. Along with this, when receiving a subscription registration request from the terminal, Adding the IP address of the terminal to the routing table; The IP address of the own device as the care-of address and the IP address of the terminal as the home address are determined by the Mobile IP method. The first recording means of the communication device that transmits to the upper network and functions as a home agent of the terminal via the second communication device Registered with Of the terminal Home agent The first communication device From the data to the care-of address of the terminal Via the second communication device If received, addressed to the IP address of the terminal corresponding to the care-of address of this data , In the same way as a terminal existing in the upper network It is characterized by transmitting data.
[0013]
The present invention also provides a Mobile IP network capable of performing communication even when a terminal moves in the network by the Mobile IP method, IP network that allows terminals to communicate by IP method A connecting device for connecting IP network Recording means for recording the IP address of the terminal existing in IP network In response to a notice of departure from the first terminal existing in the network, the IP address recorded in the recording means is deleted. IP network Exit management means to manage exit from IP network In response to the subscription request from the second terminal existing in the network, the IP address of the second terminal is recorded in the recording means. IP network A subscription management unit that manages subscription to the network, and an IP address recorded in the recording unit by the subscription management unit and the IP address of the own device as a care-of address, and through the Mobile IP network, the second address Terminal home agent And a care-of address registration requesting means for making a registration request.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
In the present invention, one Mobile IP network is an upper network, one or a plurality of non-Mobile IP networks are lower networks, and communication having a connection function at one or a plurality of connection points connecting the networks. This is realized in a configuration in which equipment (connecting device) is arranged.
[0015]
There are two types of methods depending on whether the non-Mobile IP network as the lower network is configured by one network (first embodiment) or by a plurality of networks. If the network is configured, whether the home agent of the terminal of the lower network is realized by the communication device (router) of the Mobile IP network (second embodiment) or by the communication device (connected device) of the non-Mobile IP network According to the third embodiment, it can be further divided into two systems.
[0016]
Using the above three methods, after a terminal in a non-Mobile IP network moves to another non-Mobile IP network without changing the IP address, it moves from another terminal at the source to another network Each embodiment will be described with reference to an example in which data is transmitted to a terminal that has been transmitted via a Mobile IP network. A description will be given on the assumption that the source network is the network A, the destination network is the network B, and the Mobile IP network that is the upper network of both networks is the network C.
[0017]
A communication device (concatenating device) with a connection function operates as if all mobile terminals in the lower network are Mobile IP mobile nodes for the upper network, depending on the implementation method. By performing the operation as if it were the Mobile IP home agent of the mobile terminal in the lower network, the lower network appears to the upper network as if it is operating in the Mobile IP system.
[0018]
On the other hand, the connecting device manages network route information with the mobile terminal in the network by the non-Mobile IP method for the lower level network. There are two main methods: a method of dynamic management by exchanging information between routers and mobile terminals, and a method of static management by human setting. It also manages the route of the upper network.
[0019]
(First embodiment)
FIG. 1 is a block diagram showing a network system (mobile system) configuration according to this embodiment. In FIG. 1, a mobile IP network (upper network (network C)) is connected to a router 10 as a communication device connected to a non-mobile IP network (network A) and to a communication connected to another non-mobile IP network (network B). A router 12 is provided as a device. The router 10 and the router 12 are assumed to have the same function according to the present embodiment.
[0020]
In the first embodiment, the router 10 functions as a home agent for the network A. The router 10 has a binding cache 10a that records data indicating a correspondence relationship between a home address and a care-of address of a terminal existing in the home network (a network A below the router 10). Similarly to the router 10, the router 12 has a binding cache 12a.
[0021]
Although not shown, it is assumed that there are mobile terminals that communicate with terminals existing in networks A and B in the Mobile IP network.
[0022]
Two networks A and B are shown in the non-Mobile IP network (lower network). The network A is provided with a connection device 20 as a communication device connected to the Mobile IP network, and the network B is provided with a connection device 22 as a communication device connected to the Mobile IP network. The connecting device 20 and the connecting device 22 are assumed to have the same function according to the present embodiment. The connecting devices 20 and 22 are equipped with functions related to the Mobile IP system, and have the function of impersonating the routers 10 and 12 in the Mobile IP network by operating in the same manner as a mobile terminal.
[0023]
The connecting device 20 is provided with a routing table 20a that records the IP address of a terminal existing in a lower network in association with data indicating an interface to which the terminal is connected (see FIG. 2). In FIG. 1, the interface on the Mobile IP network (router 10) side is “2”, and the interface to which the lower terminal is connected is “1”. In addition, the connecting device 22 has a routing table 22 a similar to the connecting device 20.
[0024]
In the first embodiment, the connecting device 20 impersonates a terminal in the network A, and registers the information of each terminal with the router 10 (home agent) by the Mobile IP method, so that the homepage is stored in the binding cache 10a. Record the address and care-of address. The home address and care-of address for the PC 32 match before moving, but the care-of address is changed after moving to the network B.
[0025]
In the network A, there are a server 30 and a PC (personal computer) 32 as a mobile terminal. In addition, a server 34 exists in the network B.
[0026]
In FIG. 1, the IP address of the connecting device 20 is “aγ”, the IP address of the server 30 is “aα”, the IP address of the PC 32 is “aβ”, and the IP address of the connecting device 22 is “bγ”, Server 34 Is described as “bα”.
[0027]
Next, the operation of the system in the first embodiment will be described.
Here, a case where the PC 32 existing in the network A leaves the network A and joins the network B will be described. In the following description, the PC 32 after leaving the network A and joining the network B will be described as the joining PC 32.
[0028]
Here, the router 10 at the boundary with the network A in the Mobile IP network (network C) operates as a home agent for all terminals in the network A, and the connection device at the boundary with the network C in the network A 20 operates as a mobile node of all terminals of the network A.
The connecting device 20 impersonates a terminal (server 30, PC 32) and sends information on the terminal, that is, the IP address of each terminal recorded in the routing table 20a, to the router 10 (home agent) using the Mobile IP method. Register. The router 10 records the IP address of each terminal received from the connection device 20 in the binding cache 10a as the home address.
[0029]
First, before leaving the network A, the PC 32 transmits a leave notification to the connecting device 20 (FIG. 1 (1)). Upon receiving the disconnection notification from the PC 32, the connecting device 20 deletes the entry for the PC 32 recorded in the routing table 20a (FIG. 1 (2)). That is, the connecting apparatus 20 deletes the entry in which the IP address “aβ” of the PC 32 is associated with the interface “1” as shown in FIG.
[0030]
Here, it is assumed that the PC 32 is disconnected from the network A and joined to the network B (FIG. 1 (3)). Here, there is no change of the IP address for the PC 32 (subscription PC 32).
[0031]
The concatenating device 22 of the network B to be subscribed to performs subscription registration processing for the subscribed terminal according to the flowchart shown in FIG.
[0032]
First, the subscription PC 32 issues a subscription registration request to the connecting device 22 (FIG. 1 (4)). When receiving the subscription registration request of the subscription PC 32 (Step A1), the connecting device 22 adds an entry of data indicating the interface corresponding to the IP address of the subscription PC 32 to the routing table 22a (Step A2) (FIG. 1 (5)). ). That is, since the IP address of the joining PC 32 has not been changed, entries of the IP address “aβ” and the interface “1” are added as shown in FIG.
[0033]
The connecting device 22 holds a care-of address (that is, its own IP address “bγ”) (step A3), impersonates the joining PC 32, and the home address (IP address “aβ” of the joining PC 32) and the care-of address (self-addressed). (IP address “bγ”) is transmitted to the home agent of the higher level network (Mobile IP network) by the Mobile IP method (step A4) (FIG. 1 (6)). That is, the registration request for the connecting device 22 is transmitted to the router 10 through the router 12.
[0034]
When the router 10 (home agent) receives the registration request from the connection device 22, the router 10 (home agent) registers the care-of address in the binding cache 10a. That is, as shown in FIG. 5, the entry of the home address “aβ” and the care-of address “bγ” is registered. When the router 10 completes the recording of the care-of address in the binding cache 10a, the router 10 transmits a registration response to the connecting device 22.
[0035]
The connecting device 22 receives a registration response from the router 10 (home agent) through the router 12 (step A5).
[0036]
In this way, the care-of address can be registered in the router 10 functioning as the home agent of the network A through the connecting device 22 for the PC 32 that has left and joined the network B, which is a non-Mobile IP network.
[0037]
Next, an example of the data flow after the joining PC 32 joins the network B will be described with reference to FIGS. FIG. 8 is a flowchart for explaining the operation of each data transfer process in the connecting devices 20 and 22.
[0038]
First, the routing in the non-mobile IP network from the server 34 in the subscriber's network B to the subscriber PC 32 will be described with reference to FIG.
[0039]
When data addressed to the subscription PC 32 is transmitted from the server 34, this data is transmitted to the subscription PC 32 in the network B (FIG. 6 (1)).
[0040]
On the other hand, when the connecting device 22 receives data from the lower terminal (here, the server 34) (step B4) (FIG. 6 (2)), the routing table indicates that the joining PC 32 that is the destination of this data is under command. It discriminate | determines based on the entry registered into 22a (step B5, Yes). Therefore, the connecting device 20 does not route to the upper MobileIP network (step B6).
[0041]
Next, with reference to FIG. 7, a case will be described in which routing is performed from the departure source server 30 to the router 10 (home agent) of the Mobile IP network via the connection source device 20 of the departure source.
[0042]
When the connecting device 20 receives data addressed to the subscription PC 32 from the lower terminal (here, the server 30) (step B4) (FIG. 7 (1)), the subscription PC 32 of the data transmission destination commands the routing table 20a. It is determined that it is not below (step B5, No). This routes to the upper Mobile IP network (step B7) (FIG. 7 (2)).
[0043]
Since the router (home agent) 10 knows the care-of address of the joining PC 32 from the binding cache 10a, the router (home agent) 10 transfers data to the care-of address of the joining PC 32 ((3) in FIG. 7). That is, data from the router 10 is transmitted to the connecting device 22 via the router 12.
[0044]
When the connection device 22 receives data addressed to the care-of address of the joining PC 32 (ie, addressed to itself) from the home agent (router 10) (step B1) (FIG. 7 (3)), the connecting device 22 (ie, the joining PC's home address) (IP address) (step B2) and route to a lower network (non-Mobile IP network) (step B3) (FIG. 7 (4)). As a result, data addressed to the subscription PC 32 is transmitted to the subscription PC 32.
[0045]
In this way, in the method of the first embodiment, the connecting device 22 in the lower network (network B) (non-Mobile IP network) sends the information of the subscription PC 32 to the home agent (router 10) of the Mobile IP network (upper network). A notification of the care-of address can be made by notification using the Mobile IP method. Accordingly, even if the PC 32 in the non-Mobile IP network moves to another network B, data can be routed to the joining PC 32 by the connecting device 20 of the departure source and the connecting device 22 of the joining destination.
[0046]
(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 9 is a block diagram showing a network system (mobile system) configuration according to the second embodiment.
In the second embodiment, the non-Mobile IP network (each of networks A and B) is composed of a plurality of networks, and the routers 10 and 12 of the Mobile IP network (Network C) are all terminals in the non-Mobile IP network. This is a case of functioning as a home agent. The basic configuration is the same as that of the first embodiment, and detailed description thereof is omitted.
[0047]
In the second embodiment, the router 10 at the boundary with the network A in the network C operates as a home agent for all terminals in the network A, and the connecting device 20 at the boundary with the network C in the network A It operates as a mobile node for all terminals of network A. One virtual network D (home network h for the router 10) is set in the router 10 as the home network of all terminals in the network A.
[0048]
In the second embodiment, the connecting device 20 pretends to be a terminal in the network A (here, the nearest network) and registers information of each terminal to the router 10 (home agent) by the Mobile IP method. The home address and care-of address are recorded in the binding cache 10a. The home address in the binding cache 10a is the address of the network D (home network h), and the care-of address is the address of the network A. That is, the router 10 manages a terminal existing in the network A as having been subscribed from the virtual home network h.
[0049]
In FIG. 9, the IP address of the connecting device 20 is “aγ”, the IP address of the server 30 is “hα”, the IP address of the PC 32 is “hβ”, and the IP address of the connecting device 22 is “bγ”, Server 34 Will be described as “iα”.
[0050]
Next, the operation of the second embodiment will be described.
Here, a case will be described in which the PC 32 existing in the network A leaves the network A and joins the network B (networks c and d). In the following description, the PC 32 after leaving the network A and joining the network B will be described as the joining PC 32.
[0051]
Here, the router 10 at the boundary with the network A in the Mobile IP network (network C) operates as a home agent for all terminals in the network A (here, networks a and c), and in the network A The connecting device 20 at the boundary with the network C in FIG.
FIG. 10 is a flowchart for explaining the subscription registration process (1) by the connecting device 20. In the subscription registration process (1), the connecting device 20 behaves as a terminal existing in the latest network a and registers the care-of address in the router 10.
[0052]
First, the connecting device 20 holds the IP addresses and care-of addresses of all terminals under control (the server 30 and the PC 32 in FIG. 9) (step C1). Here, the care-of addresses of all the terminals are the own IP address “aγ” of the connection device 20. Then, the connecting device 20 impersonates all terminals, and transmits information on the terminals, that is, home addresses (IP addresses) and care-of addresses (terminal addresses) recorded in the routing table 20a to the router 10 (home agent). A registration request of (own IP address) is transmitted by the Mobile IP method (step C2).
[0053]
The router 10 records the IP address of each terminal received from the connection device 20 in the binding cache 10a as the home address. For example, the PC 32 is recorded as a home address “hβ” and a care-of address “aγ” as shown in FIG.
[0054]
Next, before leaving the network A, the PC 32 transmits a leave notification to the connecting device 20 (FIG. 9 (1)). Upon receiving the disconnection notification from the PC 32, the connecting device 20 deletes the entry for the PC 32 recorded in the routing table 20a (FIG. 9 (2)). That is, the connecting apparatus 20 deletes the entry in which the IP address “hβ” of the PC 32 is associated with the interface “1” as shown in FIG.
[0055]
Here, it is assumed that the PC 32 is disconnected from the network A and joined to the network B (for example, the network d) (FIG. 9 (3)). Here, there is no change of the IP address for the PC 32 (subscription PC 32).
[0056]
The concatenating device 22 of the network B that is the subscriber performs the subscription registration process (2) for the subscribed terminal according to the flowchart shown in FIG.
[0057]
First, the subscription PC 32 issues a subscription registration request to the connecting device 22 (FIG. 9 (4)). Upon receiving the subscription registration request of the subscription PC 32 (step D1), the connecting device 22 adds an entry of data indicating the interface corresponding to the IP address of the subscription PC 32 to the routing table 22a (step D2) (FIG. 9 (5)). ). That is, since the IP address of the joining PC 32 has not been changed, entries of the IP address “hβ” and the interface “1” are added as shown in FIG.
[0058]
The connecting device 22 holds a care-of address (that is, its own IP address “bγ”) (step D3), impersonates the joining PC 32, and the home address (IP address “hβ” of the joining PC 32) and the care-of address (self (IP address “bγ”) is transmitted to the home agent of the higher level network (Mobile IP network) by the Mobile IP method (step D4) (FIG. 9 (6)). That is, the registration request for the connecting device 22 is transmitted to the router 10 through the router 12.
[0059]
When the router 10 (home agent) receives the registration request from the connection device 22, the router 10 (home agent) searches the binding cache 10a for a home address corresponding to the IP address of the joining PC 32, and changes the care-of address of the corresponding entry. That is, as shown in FIG. 14B, the care-of address “aγ” of the entry of the home address “hβ” is changed to “bγ”. When the router 10 completes the recording of the care-of address in the binding cache 10a, the router 10 transmits a registration response to the connecting device 22.
[0060]
The connecting device 22 receives a registration response from the router 10 (home agent) through the router 12 (step D5).
[0061]
In this way, the care-of address can be registered in the router 10 functioning as the home agent of the network A through the connecting device 22 for the PC 32 that has left and joined the network B, which is a non-Mobile IP network.
[0062]
Next, an example of the data flow after the joining PC 32 joins the network B will be described with reference to FIGS. 15 and 16. FIG. 16 is a flowchart for explaining the operation of each data transfer process in the connecting devices 20 and 22.
[0063]
First, routing in the non-mobile IP network from the server 34 in the subscriber network B to the subscription PC 32 will be described.
[0064]
When data addressed to the subscription PC 32 is transmitted from the server 34, this data is transmitted to the subscription PC 32 in the network B (FIG. 15 (11)).
[0065]
On the other hand, when the connecting device 22 receives data from the lower terminal (here, the server 34) (step E4) (FIG. 15 (11)), the routing table indicates that the joining PC 32 that is the destination of this data is under command. A determination is made based on the entry registered in 22a (step E5, Yes). Therefore, the connecting device 20 does not route to the upper Mobile IP network (step E6).
[0066]
Next, a case will be described in which routing is performed from the leaving server 30 to the router 10 (home agent) of the Mobile IP network via the leaving connection device 20.
[0067]
When the connecting device 20 receives data addressed to the subscription PC 32 from the lower terminal (here, the server 30) (step E4) (FIG. 15 (21)), the subscription PC 32 of the data transmission destination commands the routing table 20a. It is determined that it is not below (step E5, No). This routes to the upper Mobile IP network (step E7) (FIG. 15 (22)).
[0068]
Since the router (home agent) 10 knows the care-of address of the joining PC 32 from the binding cache 10a, it transfers data to the care-of address of the joining PC 32 (FIG. 15 (23)). That is, data from the router 10 is transmitted to the connecting device 22 via the router 12.
[0069]
When the connection device 22 receives data addressed to the care-of address of the joining PC 32 (ie, addressed to itself) from the home agent (router 10) (step E1) (FIG. 15 (23)), the connecting device 22 (ie, the joining PC's home address) IP address) is changed (step E2), and routing is performed to the lower network (non-Mobile IP network) (step E3) (FIG. 15 (24)). As a result, data addressed to the subscription PC 32 is transmitted to the subscription PC 32.
[0070]
Thus, in the method of the second embodiment, when the non-Mobile IP network is configured by a plurality of networks, the lower network (network B) (to the home agent (router 10) of the Mobile IP network (upper network) ( The connection device 22 in the non-Mobile IP network can notify the information of the subscription PC 32 by the Mobile IP system and make a registration request (change) of the care-of address. Therefore, even if the PC 32 in the non-Mobile IP network moves to another network B (network d), data can be routed to the joining PC 32 by the connecting device 20 of the departure source and the connecting device 22 of the joining destination. it can.
[0071]
(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 17 is a block diagram showing a network system (mobile system) configuration according to the third embodiment.
In the third embodiment, a non-Mobile IP network (each of networks A and B) is composed of a plurality of networks, and a connection device of the non-Mobile IP network operates as a home agent for all terminals in the non-Mobile IP network. Is the case. The basic configuration is the same as that of the first embodiment, and detailed description thereof is omitted.
[0072]
In the third embodiment, the connecting device 20 at the boundary with the network C in the network A operates as a home agent for all terminals in the network A, and simultaneously operates as a mobile node for all terminals in the network A. One virtual network D (home network h ′ for the connection device 22) is set in the connection device 20 as the home network of all terminals in the network A.
[0073]
In the third embodiment, the connection device 20 is provided with a binding cache 20b in addition to the routing table 20a.
Record the home address and care-of address for all existing terminals. The home address in the binding cache 20b is the address of the network D (home network h ′), and the care-of address is the address of the network A. That is, the connecting device 20 manages a terminal existing in the network A as having been subscribed from the virtual home network h ′.
[0074]
In FIG. 17, the IP address of the connecting device 20 is “aγ”, the IP address of the server 30 is “h′α”, the IP address of the PC 32 is “h′β”, and the IP address of the connecting device 22 is “ “bγ” and the IP address of the server 32 are assumed to be “i′α”.
[0075]
Next, the operation of the third embodiment will be described.
Here, a case will be described in which the PC 32 existing in the network A leaves the network A and joins the network B (networks c and d). In the following description, the PC 32 after leaving the network A and joining the network B will be described as the joining PC 32.
[0076]
Here, the connecting device 20 at the boundary with the network C in the non-Mobile IP network (network A) operates as a home agent for all terminals in the network A (here, networks a and c).
FIG. 18 is a flowchart for explaining the subscription registration process (1) by the connecting device 20 of the network A before the PC 32 leaves.
[0077]
First, the connecting device 20 records the IP addresses (home addresses) and care-of addresses of all terminals (server 30 and PC 32 in FIG. 17) existing in the subordinate network under command in the binding cache 20b (step F1). Here, the care-of addresses of all the terminals are the own IP address “aγ” of the connection device 20. For example, as shown in FIG. 22A, the PC 32 is recorded as a home address “h′β” and a care-of address “aγ”.
[0078]
Next, before leaving the network A, the PC 32 transmits a leave notification to the connecting device 20 (FIG. 17 (1)). Upon receiving the withdrawal notification from the PC 32, the connecting device 20 deletes the entry for the PC 32 recorded in the routing table 20a (FIG. 17 (2)). That is, the connecting device 20 deletes the entry in which the IP address “h′β” of the PC 32 is associated with the interface “1” as shown in FIG.
[0079]
Here, it is assumed that the PC 32 is disconnected from the network A and joined to the network B (for example, the network d) (FIG. 17 (3)). Here, there is no change of the IP address for the PC 32 (subscription PC 32).
[0080]
The connecting device 22 of the network B to which the subscriber is subscribed executes the subscription registration process (2) for the subscribed terminal according to the flowchart shown in FIG.
[0081]
First, the subscription PC 32 issues a subscription registration request to the connecting device 22 (FIG. 17 (4)). When receiving the subscription registration request of the subscription PC 32 (step G1), the connecting device 22 adds an entry of data indicating the interface corresponding to the IP address of the subscription PC 32 to the routing table 22a (step G2) (FIG. 17 (5)). ). That is, since the IP address of the joining PC 32 has not been changed, entries of the IP address “h′β” and the interface “1” are added as shown in FIG.
[0082]
Further, the connecting device 22 holds the care-of address (that is, its own IP address “bγ”) (step G3), impersonates the joining PC 32, and the home address (IP address “h′β” of the joining PC 32) and the care-of address. A registration request (ringing update) of (your own IP address “bγ”) is transmitted to the home agent of the higher level network (Mobile IP network) by the Mobile IP method (step G4) (FIG. 17 (6)). That is, the registration request for the connecting device 22 is transmitted to the connecting device 20 through the router 12 and the router 10.
[0083]
When the connection device 20 (home agent) receives the registration request from the connection device 22 (step F2), it searches the binding cache 20b for the home address corresponding to the IP address of the joining PC 32 and changes the care-of address of the corresponding entry. (Step F3). That is, as shown in FIG. 22B, the care-of address “aγ” of the entry of the home address “h′β” is changed to “bγ”. When the connection device 20 completes the recording of the care-of address in the binding cache 20b, the connection device 20 transmits a registration response to the connection device 22 (step F4).
[0084]
The connecting device 22 receives a registration response from the router 10 (home agent) through the router 12 (step G5).
[0085]
In this way, the care-of address can be registered in the connecting device 20 that functions as the home agent of the network A through the connecting device 22 for the PC 32 that has left and joined the network B, which is a non-Mobile IP network.
[0086]
Next, an example of the data flow after the joining PC 32 joins the network B will be described with reference to FIGS. FIG. 24 is a flowchart for explaining the operation of each data transfer process in the connecting devices 20 and 22.
[0087]
First, routing in the non-mobile IP network from the server 34 in the subscriber network B to the subscription PC 32 will be described.
[0088]
When data addressed to the subscription PC 32 is transmitted from the server 34, this data is transmitted to the subscription PC 32 in the network B (FIG. 23 (11)).
[0089]
On the other hand, when the connecting device 22 receives data from a lower terminal (here, the server 34) (FIG. 15 (11)), it is registered in the routing table 22a that the joining PC 32 that is the destination of this data is in command. Judged based on the entry. Therefore, the connecting device 20 does not route to the upper Mobile IP network.
[0090]
Next, a case will be described in which routing is performed from the leaving server 30 to the connecting device 20 (home agent) through the Mobile IP network via the leaving connection device 20.
[0091]
When the connecting device 20 captures data addressed to the subscription PC 32 from the lower terminal (here, the server 30) (step H1) (FIG. 23 (21)), the subscription PC 32 as the data transmission destination commands the routing table 20a. It is determined that it is not below, that is, it is separated (step H2, Yes). Since the connection device 20 knows the care-of address of the joining PC 32 from the binding cache 20b, the connection device 20 routes the care-of address of the joining PC 32 to the upper Mobile IP network (step H3) (FIG. 23 (22)).
[0092]
That is, the data from the connection device 20 is transmitted to the connection device 22 via the router 10 and the router 12.
[0093]
When the connecting device 22 receives data addressed to the care-of address of the joining PC 32 (ie, addressed to itself) from the home agent (connecting device 20) (step H1) (FIG. 23 (22)), the connecting device 22 (ie, the joining PC). To the lower network (non-Mobile IP network) (step H4) (FIG. 23 (23)). As a result, data addressed to the subscription PC 32 is transmitted to the subscription PC 32.
[0094]
Thus, in the method of the third embodiment, when the non-Mobile IP network is configured by a plurality of networks, the home network (connecting device 20) of the non-Mobile IP network (lower network) is connected to the lower network (Network B). ) The connecting device 22 in the (non-Mobile IP network) can notify the information of the subscription PC 32 and make a registration request (change) of the care-of address. Therefore, even if the PC 32 in the non-Mobile IP network moves to another network B (network d), data can be routed to the joining PC 32 by the connecting device 20 of the departure source and the connecting device 22 of the joining destination. it can.
[0095]
As described above, according to the method according to each embodiment, when a network that cannot adopt the Mobile IP scheme is constructed due to restrictions on the transmission capacity and quality of the network, not only the mobility within the network but also the Mobile IP Mobility with a network, that is, seamless communication between a terminal of a non-Mobile IP network and a terminal of a Mobile IP network, and between terminals of different non-Mobile IP networks via the Mobile IP network can be ensured.
[0096]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
[0097]
【The invention's effect】
As described above in detail, according to the present invention, a Mobile IP network capable of performing communication even when a terminal moves in the network by the Mobile IP method is used as an upper network, and the terminal is used by a method different from the Mobile IP method. A non-Mobile IP network that can communicate even if it moves through the network is a lower network, and functions as a terminal that conforms to the Mobile IP system for the upper network between the upper network and the lower network. For a network, a connection device that functions as a terminal that conforms to a system different from the Mobile IP system is arranged to enable communication between terminals participating in different networks while ensuring mobility.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a network system (mobile system) configuration according to a first embodiment.
FIG. 2 is a view showing an example of data recorded in a routing table 20a in the first embodiment.
FIG. 3 is a flowchart for explaining a subscription registration process by the connecting device 22 in the first embodiment.
FIG. 4 is a view showing an example of data recorded in a routing table 22a in the first embodiment.
FIG. 5 is a view showing an example of data recorded in a binding cache 10a according to the first embodiment.
FIG. 6 is a diagram for explaining routing in the non-mobile IP network from the server 34 in the network B of the subscription destination to the subscription PC 32 in the first embodiment.
FIG. 7 is a diagram for explaining a case in which routing is performed from the leaving server 30 to the router 10 (home agent) of the Mobile IP network via the leaving connection device 20 in the first embodiment.
FIG. 8 is a flowchart for explaining the operation of each data transfer process in the connecting devices 20 and 22 according to the first embodiment.
FIG. 9 is a block diagram showing a network system (mobile system) configuration according to the second embodiment.
FIG. 10 is a flowchart for explaining a subscription registration process (1) by the connecting device 20 in the second embodiment.
FIG. 11 is a flowchart for explaining a subscription registration process (2) by the connecting device 22 in the second embodiment.
FIG. 12 is a diagram showing an example of data recorded in a routing table 20a in the second embodiment.
FIG. 13 is a diagram showing an example of data recorded in a routing table 22a in the second embodiment.
FIG. 14 is a diagram showing an example of data recorded in a binding cache 10a according to the second embodiment.
FIG. 15 is a diagram for explaining a data flow after a joining PC 32 joins a network B in the second embodiment.
FIG. 16 is a flowchart for explaining the operation of each data transfer process in the connecting devices 20 and 22 according to the second embodiment.
FIG. 17 is a block diagram showing a network system (mobile system) configuration according to the third embodiment.
FIG. 18 is a flowchart for explaining a subscription registration process (1) by the connection device 20 of the network A before the PC 32 is detached in the third embodiment.
FIG. 19 is a flowchart for explaining a subscription registration process (2) by the connecting device 22 in the third embodiment.
FIG. 20 is a diagram showing an example of data recorded in a routing table 20a according to the third embodiment.
FIG. 21 is a diagram showing an example of data recorded in a routing table 22a according to the third embodiment.
FIG. 22 is a diagram showing an example of data recorded in a binding cache 20b according to the third embodiment.
FIG. 23 is a diagram for explaining a data flow after the joining PC 32 is joined to the network B in the third embodiment.
FIG. 24 is a flowchart for explaining the operation of each data transfer process in the connecting devices 20 and 22 according to the third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10,12 ... Router, 10a, 12a, 20b, 22b ... Binding cache, 20, 22 ... Connection apparatus, 20a, 22a ... Routing table, 30, 34 ... Server, 32 ... PC.

Claims (1)

The Mobile IP network that can communicate even if the terminal moves in the network by the Mobile IP system is an upper network, and the first and second IP networks that can be communicated by the terminal by the IP system are lower. Network and
The upper network includes first and second communication devices connected to the first and second IP networks, respectively.
Between the upper network and each of the first and second IP networks of the lower network , the upper network functions as a terminal according to the Mobile IP scheme, and the IP scheme for the lower network A first connection device and a second connection device provided with a routing table that records the IP addresses of the terminals existing in the lower network ,
The first communication device is:
A first recording unit that functions as a home agent of the first IP network and records data indicating a correspondence relationship between a home address and a care-of address of a terminal existing in the first IP network;
The second communication device is:
A second recording unit that functions as a home agent of the second IP network and records data indicating a correspondence relationship between a home address and a care-of address of a terminal existing in the second IP network;
The first connecting device includes:
In response to a leave notification from the terminal existing in the first IP network in the lower network, the IP address of the terminal is deleted from the routing table,
The second connecting device is:
When the terminal existing in the first IP network in the lower network moves to the second IP network and receives a subscription registration request from the terminal, the IP address of the terminal is set. Add to the routing table, send the IP address of the own device as the care-of address and the IP address of the terminal as the home address to the upper network by the Mobile IP method , and via the second communication device Registering with the first recording means of the communication device functioning as a home agent of the terminal ;
When data addressed to the care-of address of the terminal is received from the first communication device as the home agent of the terminal via the second communication device, the IP address of the terminal corresponding to the care-of address of the data A network connection method , wherein data is transmitted to a destination in the same manner as a terminal existing in the upper network .

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