JP3183784B2 - Data transfer system and data transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transfer system and a data transfer method, and more particularly to an ATM (Asynchronous).
ous Transfer Mode (Asynchronous Transfer Mode) This is applicable to connectionless communication by a communication method.

[0002]

2. Description of the Related Art In recent years, in order to realize B-ISDN, AT
Technology development of M communication is underway. For example, the technical development of the ATM communication system using the connectionless (CL) system has been actively carried out.

(A) For example, in the broadcast communication method of connectionless communication, ITU-T Recommendation I.-I. 364
Has proposed the following method.

(1) Centralized control type transfer method: A method for centrally transferring multicast data by a group address resolution function (GAA) placed in a network.

The GAA waits for a correspondence table between a group address GA to be processed and individual addresses of all terminals included in the GA, converts the group address GA into individual addresses using the table, It has a function of distributing / transferring the protocol data unit PDU.

(2) Centralized control type transfer method by NGAA ... This is a method in which multicast transfer is performed stepwise by GAA and nested GA resolution function (NGAA).

[0007] (3) Distributed control type transfer method: A method in which the multicast transfer is shared by GAA placed in each network.

[0008] Of these transfer methods, there is a problem in terms of processing load and delay after giving priority to the specificity of the control mechanism and ease of management. The shape transfer method seems to be the most feasible.

Therefore, a multicast transfer mechanism based on the centralized control transfer method will be described with reference to a network model shown in FIG. The terminals 1 to 4 are members of the group address GA1.

First, the terminal 1 entered in the GA 1
Sends a PDU (GA-PDU) having a group address. Next, the GA-PDU is once transferred to the GAA. Next, the GAA transfers the GA-PDU to all the terminals 2, 3, and 4 entered in the GA1. At this time, it is not transferred to the terminal 1 that is the sender. still,
GA-PDU from a subscriber not entered in GA
Was discarded by the GAA screening function.

FIG. 3 shows an example of a connectionless communication network. The network has multiple ATM switching functions and connectionless service functions (C
LSF). This ATM exchange function provides a PVC connection between the terminal and the CLSF or between the CLSF and the CLSF. The ATM exchange function accommodates a plurality of terminals.
(Permanent Virtual Channel
In 1), it is composed of a mesh. CLSF is CLNAP-
Provides transfer of PDU or CLNIP-PDU.

The CLSF has a protocol conversion function (P
CF) and VPI based on the destination address of the PDU
/ VCI is selected. The routing method of the connection network is described as follows.
-Routed with the destination address of the PDU. CLS
The route between the F-CLSF is routed by the destination address of the CLNIP-PDU. In the destination address, one CLSF has one station number, and the subscriber address always includes the station number.

According to the routing table, the CLSF has (1) the correspondence between the subscriber address accommodated in the own CLSF and the VC indicating the route of the subscriber, and (2) the CLSF connected to the own CLSF. Station number and CLSF
Of the CLNAP-PDU or CLNIP- based on the information of the routing table.
PDU routing is performed.

Therefore, a detailed description will be given using the table contents shown in FIG . First, communication from terminal A to terminal B will be described as an example of routing to a terminal in the same station.

(1) First, terminal A uses CLNAP- with the address (22-0002) of terminal B as the destination address.
After cellizing the PDU, it is sent to the ATM switching function via the communication channel (VC # 2).

(2) Next, the ATM switching function sets the cell to C
The data is sent to the LSF, the CLSF extracts the VC number (VC # 3) for the destination address from the routing table, and replaces the cell with the VC number (VC # 2).

(3) Next, the ATM exchange function sends to the terminal B according to the changed VC number.

Next, communication from terminal A to terminal C will be described as an example of routing between terminals in another station.

(4) Terminal A receives the address of terminal C (55-
0001), the CLNAP-PDU having the destination address is converted into a cell, and the ATM exchange function is used to make the communication channel (VC
Send in # 2).

(5) The ATM switching function connected to the terminal A sends the cell to CLSF # 0. Since the CLSF has no destination address registered in the routing table, the VC number (V) corresponding to the station number (55) of that address is not registered.
C # 1) and takes out the VC number (VC # 2) of the cell.

(6) The ATM switching function sends the cell to the ATM switching function to which the CLSF # 1 of the station number 55 is connected by the replaced VC number.

(7) The ATM switching function connected to CLSF # 1 sends the data cell to CLSF # 1. CLSF
# 1 extracts the VC number (VC # 4) for the destination address from the routing table, and replaces the VC number (VC # 1) of the cell.

(8) The ATM exchange function connected to the terminal C sends to the terminal C with the replaced VC number.

It is fully conceivable that this terminal must move for some reason. It is also conceivable that there is a demand for immediate communication at the destination. The ability to immediately communicate at the destination is called the portability function.

Considering a normal telephone routing algorithm, the same telephone number can be used when the moving destination is in the same office. However, when the station is different at the destination, a new telephone number with the station number is given, so that the number is different. Therefore, if the number is different at the destination, communication cannot be performed unless the changed number is given to the other party.

The future, like a pen PC is expected to be terminal, it may be generated that want to immediately connect to the connectionless (CL) network in such work destination. In this case, the amount of processing for notifying that the number has been changed by a routing mechanism such as a normal telephone is enormous, which is not practical.

Further, considering that the number changes each time the mobile station moves out of the station, there is a possibility that the number resource is exhausted, which is not desirable. This is because a number used once is generally not used for a certain period of time in order to prevent a wrong telephone call or the like. Considering this, the numbers must be able to communicate with the same number at the destination.

[0028]

[Problems to be solved by the invention]

(A) The broadcast function described in (A) is one of closed communication functions (communication functions provided to a closed group (a set of specified subscribers for the purpose of information sharing)). .
However, conventionally, closed network communication, that is, operation of multicast and security management thereof are to be performed by a network administrator.

Therefore, there is a problem that the expansion or contraction of the closed group can be facilitated on the user side, and the closed group members required to prevent abuse of information in the closed group cannot be managed.

In view of the above, there has been a demand for the provision of a "data transfer system which allows the user to permit and withdraw from the new subscription and allows the user to perform security management".

(I) In the network described in (a) above, considering the portability function, the local CLS
In the movement within F, routing is possible if the logical channel is moved along with the movement of the physical channel. However, for mobility across CLSF, routing becomes a problem if the subscriber's number remains the same.

An example of this problem will be described. When terminal B in FIG. 4 moves from CLSF # 0 to CLSF # 1,
Deleted from the routing table of CLSF # 0, CL
Register it in the SF # 1 routing table. FIG. 5 shows this.

Referring to FIG. 5, when a communication is made from the terminal A, the transmitted data is CL because there is no terminal number (22-0002) in the routing table.
Discarded in SF # 0. When communication is performed from the terminal C, the CLSF is determined by the station number (22-XXXX).
Data flowing to # 0 or the subscriber number of terminal B (22-0)
002), it is not possible to determine whether the data is on the subscriber side.

As described above, occurrence of inconsistency in the routing table is a factor that hinders the portability function. A routing algorithm was needed to solve this.

In view of the above, it has been requested to provide a "data transfer method in which the terminal number is fixed and the terminal can move to the same number even at the terminal destination".

[0036]

SUMMARY OF THE INVENTION (1) Therefore, the present invention provides a data transfer system for transferring data in which a destination terminal group identification number is set from a calling terminal to a called terminal based on routing information. Build with
You.

That is, (a) under the management of the network side
A switching device having routing information; and
Terminal for the receiving terminal group under the control of the user
Determines et join request or leave request, the request is granted
In this case, by constructing with the supervisor function terminal that instructs the switching device to change the routing information,
To solve the above problems.

(2) As an invention for solving the above-mentioned problem (i), the present invention includes a connectionless function unit for performing a connectionless type line connection, and includes a calling terminal identification number and a called terminal identification number. This is a data transfer method of a system in which data in which a number or the like is set is transferred from a calling terminal to a called terminal based on routing information, and a terminal connected to the system can move by changing a connection point on the system.

Further, according to the present invention, the number of the moved terminal and the channel of the destination connectionless function unit are registered in the routing table of the connectionless function unit before the terminal is moved, and the destination connectionless function unit is also registered in the destination table. Add a mobile terminal number and a channel for data delivery to the routing table.

When both the delivery channel on the terminal side and the delivery channel on the connectionless function unit are registered, control is performed to preferentially use the delivery channel on the terminal side. The received data for the moved terminal is delivered to the destination connectionless function unit via the connectionless function unit before the movement, and the destination connectionless function unit sends the data to the terminal side.

[0041]

According to the data transfer system of the invention of the above (1) , the terminal under the control of the user is provided with the supervisor function unit, so that it is easy to join or leave the closed group.
In this way, it is possible to provide a terminal with a flexible closed communication operation. Further, the processing load on the network side can be reduced.

Therefore, it is necessary to permit or withdraw new subscribers.
User (not the network administrator)
Can be limited to those that meet the volume level, it is possible to perform security management for data on the user side.

Further, according to the data transfer method of the invention (2), data can be transferred between terminals even if the terminal moves to any connection point in the system and is connected. Updating or addition of routing information of a terminal in a station can be easily performed only by changing the connectionless function unit before moving and the connectionless function unit at the moving destination.

[0044]

Next, a preferred embodiment of the present invention will be described with reference to the drawings. "First Embodiment": The first embodiment is an embodiment according to the first invention. Therefore, in this embodiment, in a data transfer system that copies a packet having a header group ID number transmitted from a calling terminal to a destination terminal based on routing information in the device and routes the packet, the called party One or a plurality of supervisors in a group for examining new join and withdrawal requests are configured, and a function of changing routing information based on a registration request and a reduction request from the supervisor is configured to implement broadcast communication.

FIG. 1 is an explanatory diagram of the network system model of the first embodiment. In FIG. 1, the system includes terminals 1 to N, a group address resolution function unit GAA,
It is composed of networks 11 to 13. FIG. 1 illustrates the operation of a GA member update algorithm in which a terminal N newly joins a member of a group address GA1 in a network model.

FIG. 6 is a sequence diagram for explaining the operation of FIG. This will be described with reference to FIG .

First, in step S1, the terminal N
A new subscription request is issued to the terminal 1 which is the GA supervisor of No. 1. Next, the terminal 1 that has received the new subscription request in step S2 examines whether or not to accept the terminal N as a member of GA1, and if it accepts it, asks the GAA to add the terminal N to the member of GA1. Request.

Next, in step S3, the GAA sets the terminal 1
Is performed according to the request, and the terminal 1 is notified of the end of the update. Next, in step S4,
The terminal 1 notifies all the GA members that the terminal N has joined the GA1 by using the multicast for the GA1 (step S5). As a result, the terminal N
You know that you have joined A1.

It should be noted that the withdrawal from the GA member is also performed by this algorithm, but the GA supervisor needs to notify the withdrawn terminal that the withdrawal procedure has been completed.

(Effects of First Embodiment) According to the first embodiment described above, it is possible to easily join / withdraw from a closed group, and to provide a user with more flexible closed communication operation. In addition, in the permission method by the GA supervisor, the user can arbitrarily set a permission level according to the purpose of use of the closed group, and thus the degree of freedom of closed communication use is considered to be high.

Also, on the network side, the application of this algorithm does not require a complicated control mechanism, so that there is an advantage that the processing load overhead can be suppressed.

"Second embodiment": This second embodiment
This is an embodiment according to the invention of FIG. In the second embodiment, the number of the moved terminal and the channel destined for the CLSF of the movement destination are registered in the routing table of the CLSF before the movement, and the number of the subscriber and the delivery method for the delivery are also registered in the CLSF of the movement destination. When a delivery channel is registered on both the subscriber side and the CLSF side in order to add a channel and avoid reversal, control is given to give priority to the subscriber side.

Further, the data transfer device is configured to transmit the received data to the moved terminal via the CLSF before the movement, and to send the data to the subscriber side in the CLSF of the movement destination delivered to the CLSF of the movement destination.

Therefore, a disconnection / connection procedure when moving by the portable routing algorithm of the data transfer device will be described. Here, a case where terminal B moves as shown in FIG. 5 using the network of FIG. 3 as a model will be described first.

(1) Regarding “when the terminal is disconnected”
Considering the cutting procedure, the sequence is as shown in FIG. First, in S10 (disconnection request due to movement), a disconnection request due to movement is issued from terminal A to CLSF # 0. Then S
CLS in 11 (deletion of routing table registration)
F # 0 deletes the part of the routing table of the destination address of the mobile terminal in response to the disconnection request due to the movement.
Next, in S12 (disconnection completed), CLSF # 0 issues a disconnection completion to the mobile terminal. The terminal receiving this can be moved. Such processing enables cutting.

After the disconnection, it is assumed that, for example, terminal A comes to access terminal B while moving. Data is CLS
It is discarded in F # 0 (step S13). It is considered that terminal A comes to access many times without knowing that terminal B is not connected. This means that traffic increases on a connectionless (CL) network and resources are wasted.

Therefore, FIG. 7 shows a network model that solves this problem. In FIG. 7, the network includes ATM switching function units 21 to 22, CLSF
# 0 to # 1, a server 20, and terminals A to D. In FIG. 7, it is assumed that a server 20 having movement information is provided. Therefore, the server 20 receives the protocol data unit PDU addressed to the moving terminal,
It has a function of sending movement information to the source of the PDU.

That is, when a packet is sent to a disconnected terminal, a packet or cell for notifying the calling terminal that the terminal is absent is sent.

The operation will be described with reference to the sequence diagram of FIG. First, in step S20 (disconnection request due to movement), a disconnection request due to movement is issued from terminal B to CLSF # 0. Next, in S21 (registering the server channel in the routing table), CLSF # 0 registers the server channel in the routing table corresponding to the destination address of the mobile terminal A in response to the disconnection request due to movement.

Next, at S22 (cutting completed), the CLSF
# 0 issues a disconnection completion to the mobile terminal A. The terminal receiving it becomes mobile. In this way, when another terminal comes to access while moving, the data is sent to the server (S24), and the movement information is sent to the calling terminal (S25). The movement information includes a movement completion date and time.

(2) Next, in the connection of the terminal that has moved,
The connection procedure will be described using the sequence of FIG. 11 and the network configuration diagram of FIG. Here, the moved terminal A
It is assumed that a connectionless (CL) communication channel is not established when a connection is made to the CLSF at the destination. Then, it is assumed that a connection-less (CL) communication channel is acquired using a fixedly assigned control channel. Hereinafter, description will be made in order.

First, in step S30, the terminal A accommodates the C
A connection request is issued to LSF # 1. Next, in S31, the CLSF # 1 knows from the connection request that the terminal has moved. By the station number of this terminal, C of this station number
A mobile connection confirmation is issued to LSF (# 0). Next, S32
According to the received mobile connection confirmation, the CLSF # 0 prepares to rewrite the channel number of the routing table with the channel number of the accommodated CLSF if the terminal number is registered (if rewritten, the The terminal is not connected and will be discarded.)

Next, in S33 (permission), CLSF #
0 issues permission to CLSF # 1. Next, in S34 (routing rewriting instruction), a rewriting instruction is issued to CLSF # 0 (S34), and a connection completion (giving a communication channel) is issued to terminal A (S35). This issuance is preferably performed at the same time as possible so as not to discard the data.

A function that must be newly added to CLSF is a routing priority control function. This priority control function is a function to select the channel number with priority when there is a terminal number that matches all the terminal numbers when the same station number exists in the routing table.

That is, at the time of routing information search, both a procedure of searching from all of the destination terminal identification numbers and a procedure of searching from the station number of the destination terminal identification number are executed. Is output.

With the above processing, connection can be established and communication becomes possible.
Explain how routing is done to actually communicate. First, the routing between the terminals C and B in the station where the terminal B is currently accommodated will be described with reference to FIG.

First, the terminal C receives the address of the terminal B (22-0).
After the CLNAP-PDU having the destination address of "002" is converted into a cell, the ATM switching function unit 22 transmits the communication channel (V
C # 4). Next, the ATM switching function unit 22 sends the cell to CLSF # 1, which extracts the VC number for the destination address from the routing table. Since both the station number and the destination address are registered, the VC number (VC
Take out # 6). The VC number of the cell is changed to its VC number (V
C # 6).

Next, the ATM switching function unit 22 sends the cell to the terminal B using the changed VC number. The routing is performed as described above.

The routing between the terminal B and a terminal accommodated in a different station will be described. Data addressed to the terminal B is always transmitted to the CLSF (# 0) before the movement. The cell sent is the CLSF currently accommodated by the routing table of the CLSF before moving by the destination address.
(# 1). After that, it is the same as the above-mentioned routing method.

Each time the C is moved, the C
Via LSF. However, if the movement is repeated many times, C
There is a problem that the number of passing LSFs increases and the delay increases. To solve this, the first registered C
For the LSF, if there is a relay address registered with the same station number as the number of the terminal to be moved to the routing table at the time of disconnection after the second movement, if there is a CL of that station number,
The channel corresponding to the number of the moving terminal in the routing table in the SF is changed to the server managing the movement information.

The CLSF that is about to disconnect disconnects from the registered routing table. As a result, the number of CLSF passes is one more than the shortest. This should not cause any problems.

(Effect of Second Embodiment) According to the second embodiment described above, by using the above-described routing mechanism, the terminal number is fixed, and communication is performed with the same number at the terminal moving destination. It is possible to perform communication no matter where the terminal moves. Also, the update / addition of the routing information of the terminal in the station for realizing the portability function is performed in the CLSF before the movement.
And changing the destination CLSF. It is considered that the data transmission delay is small enough to cause no problem. It is considered that high-speed routing is also maintained.

(Other Embodiments) (1) In the first embodiment described above, it is preferable that the supervisor terminal is provided in a plurality of systems.

(2) In the second embodiment, the ATM
Switching function unit, connectionless service function unit CLSF
Can be applied to a system provided with three or more.

(3) Further, the server 20 of the second embodiment is
It can also be realized by a configuration realized by a terminal.

(4) Further, it is considered that the above-described data transfer can be applied to the transfer of a variable-length packet and the transfer of a fixed-length packet.

[0077]

As described above, the data transfer system according to the first aspect of the present invention provides a data transfer system under the control of a root
Switching device that has
Judge a request to join or withdraw from the terminal for the terminating terminal group, and if the request is granted,
Supervisor function end to instruct change of routing information
With the end, you can set up a new
It is conceivable that it is possible to manage the allowable level of permission and withdrawal, and to enable security management by the user .

In the data transfer method according to the second invention, the number of the moved terminal and the channel of the destination connectionless function unit are registered in the routing table of the connectionless function unit before the terminal movement, and The connectionless function unit also adds a mobile terminal number and a channel for data delivery to the routing table, and if both the delivery channel on the terminal side and the delivery channel on the connectionless function side are registered, the subscriber Control to preferentially use the delivery channel on the side, and receive data for the moved terminal is delivered to the destination connectionless function unit via the connectionless function unit before movement, and the destination connectionless function In the department, by sending data to the subscriber side, the terminal number is fixed without changing and the same at the destination Data transfer can be performed at issue.

Therefore, according to the above-mentioned invention, it is considered that the functionality of connectionless communication by the ATM communication system can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a network model according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional example.

FIG. 3 is an explanatory diagram of a conventional example.

FIG. 4 is an explanatory diagram of a conventional example.

FIG. 5 is an explanatory diagram of a conventional example.

FIG. 6 is an explanatory diagram of a processing sequence according to the first embodiment.

FIG. 7 is an explanatory diagram of a network model according to a second embodiment.

FIG. 8 is an explanatory diagram of a processing sequence according to the second embodiment.

FIG. 9 is an explanatory diagram of a processing sequence according to the second embodiment.

FIG. 10 is an explanatory diagram of a network model according to a second embodiment.

FIG. 11 is an explanatory diagram of a processing sequence according to the second embodiment.

[Explanation of symbols]

1 to N terminal, 11 to 12 network, 21 to 22
... ATM switching function unit, CLSF ... Connectionless service function unit, GAA ... Group address resolution function unit, G
A: Group address.

Continuation of front page (72) Inventor Kazutaka Hanaki 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-4-249938 (JP, A) JP-A-4 JP-A-6-205006 (JP, A) JP-A-2-276336 (JP, A) JP-A-6-85830 (JP, A) JP-A-6-337824 (JP, A) JP-A-5-83260 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 H04L 12/18

Claims (2)

(57) [Claims] 1. A data transfer system for transferring data in which a destination terminal group identification number is set from a calling terminal to a called terminal based on routing information, wherein the data transfer system has routing information managed by a network.
Exchange device to be connected and the terminal for the terminating terminal group under the control of the user side.
To determine the subscription request or request for withdrawal from the end, request the permission of
Instructs the above exchange to change the routing information
Data transfer system, characterized in that it comprises a Shimesuru supervisor function terminal. 2. A connectionless function unit for performing a connectionless line connection, wherein data in which a source terminal identification number and a destination terminal identification number are set are transferred from the originating terminal to the destination terminal based on routing information. A method of transferring data in a system in which a terminal connected to the system can move by changing a connection point on the system, wherein the routing table of the connectionless function unit before the terminal is moved includes the number of the moved terminal and Register the channel of the connectionless function unit of the moving destination, and also add the number of the mobile terminal and the channel for data delivery to the routing table in the connectionless function unit of the moving destination. If both of the delivery channels on the mobile side are registered, the delivery channel on the The priority control is performed, and the received data for the moved terminal is delivered to the destination connectionless function unit via the connectionless function unit before the movement, and is transmitted to the destination connectionless function unit. Sending data to the terminal side.