JPH1013469A - Data communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data communication system corresponding to a multiprotocol. SOLUTION: A data terminal 1 operates on a network layer and a data link layer as a protocol termination point and outputs prescribed data. When the data is supplied to a protocol termination device 5 through a moving station 2, a protocol termination device 1 terminates the protocol of the data link layer and does not terminate the protocol of the network layer. When communicating data between the data terminal 1 and a network N2, it is not necessary to manage the protocol used in the network layer in a network N1. Thus, the network N1 can use any protocol to the network layer and it can flexibly correspond to the multiprotocol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data communication system suitable for performing data communication using a multi-protocol.

[0002]

2. Description of the Related Art With the development of the information society, data communication has been rapidly spreading in the field of mobile communication.
In this data communication, a network (communication network) connected to a data terminal is connected to each other, and data communication may be performed via a plurality of networks.
As a protocol in this case, OSI (Open System Interconnection) designed in a hierarchical manner is representative. In OSI,
The communication function is divided into seven layers (layers) so that data transfer between different data terminals can be performed efficiently. These layers include a physical layer, a data link layer, a network layer, a transport layer, a session layer, a presentation layer, and an application layer in order from the lower layer.

Here, the physical layer manages electrical, mechanical and physical conditions, and guarantees transmission of a bit string. For example, a waveform of an electric signal and an arrangement of connector pins are managed in the physical layer. In addition, the data link layer guarantees that data is reliably transferred by detecting and recovering a bit error occurring on a transmission path between systems that communicate with each other. Further, the network layer uses various networks such as a data communication network, manages a relay and routing function for establishing a communication path with a data terminal at the other end as a partner, and guarantees data transmission.

[0004]

In the data communication performed through a plurality of networks, the data link layer and the network layer are terminated in each network. However, since the network layer manages the routing information of data, when the network layer is terminated in the network, it is necessary to manage the routing information in the network. In this case, if the network layer is made to support multi-protocols, it is necessary to manage which protocol is used in the network layer in the network, and further manage route information used for each protocol. there were.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a data communication system capable of reducing a load on a network in data communication and flexibly supporting a multi-protocol.

[0006]

According to the first aspect of the present invention, at least a first layer, a second layer, and a third layer are provided in order from a lower layer of a protocol. In a data communication system for performing data communication between a plurality of communication networks, a data terminal connected to the communication network for generating data to be transmitted, and a data terminal connected to the second layer without terminating the third layer protocol. And a protocol terminator for terminating the protocol.

Further, in the invention according to claim 2,
In order from the lower layer of the protocol, at least the first layer,
In a data communication system having a second layer and a third layer and performing data communication between a plurality of communication networks including a mobile communication network, a data terminal for generating data to be transmitted is connected to the data terminal. A mobile station, the mobile communication network including a base station that performs wireless data communication with the mobile station in a predetermined area, and a relay station that performs data communication with the base station; and a protocol of the third layer. A protocol terminator for terminating the second layer protocol without terminating the protocol.

[0008] Further, in the invention according to claim 3,
A data communication system that arranges the protocol terminator connected to the relay station in the mobile communication network,
When performing data communication from the data terminal to the protocol terminating device, the first layer uses a packet multiplexing communication method having an order control function.

Further, in the invention according to claim 4,
A packet multiplex communication is performed between the base station and the protocol terminating device by wire. Further, in the invention according to claim 5, the protocol terminating device is arranged in the communication network other than the mobile communication network. In the invention according to claim 6,
A data communication system in which at least two of the protocol terminating devices are arranged in the communication network, wherein one of the protocol terminating devices terminates a protocol different from the protocol of the second layer terminated by the other of the protocol terminating devices. It is characterized by the following.

[0010] In the invention according to claim 7,
In the data communication between the data terminal and the protocol terminating device, the second layer protocol having a serial link property is used.
Further, in the invention according to claim 8, the first layer is a layer corresponding to a physical layer of the open system interconnection reference model, and the second layer is the open system interconnection reference. The third layer is a layer corresponding to a data link layer of the model, and the third layer is a layer corresponding to a network layer of the open system interconnection reference model.

[0011]

DETAILED DESCRIPTION OF THE INVENTION First Embodiment 1: Configuration of First Embodiment First, a configuration of a first embodiment will be described with reference to the drawings. FIG. 1 is a block diagram of a first embodiment according to the data communication system of the present invention. In the figure, 1 is a data terminal, which is composed of a personal computer or the like,
There, various data such as image data and audio data are generated and output as communication data. N1, N
2 and N3 are networks, which are mutually connected. The types of the networks N1, N2, and N3 may be of any type, but in the present embodiment, a mobile communication network is taken as an example of the network N1. As the networks N2 and N3, for example, communication networks such as the Internet and ISDN can be used. Network N
The main part 1 is composed of the following parts.

First, reference numeral 2 denotes a mobile station connected to the data terminal 1, which is constituted by a mobile phone or the like. In addition, there are many mobile stations other than those shown in the figure, and an identification number is given to each mobile station to identify them. Also, 3
Is a base station, and when the mobile station 2 is located in a predetermined area, performs data communication with the mobile station via the wireless interface IF. A relay station 4 performs data communication with the base station 3 by wire. Reference numerals 5 and 6 denote protocol terminators connected by wire to the relay station 4, terminating the protocol of the data link layer, and performing data communication with other networks N2 and N3.

From the data terminal 1 to the protocol terminating device 5,
The packet multiplexing communication method known in the physical layer is used as the communication method performed between the groups. This allows
Data transmission is performed efficiently. In the packet multiplex communication in this example, a frame is formed by adding error correction data to transmission data and controlling the transmission order of the data. Therefore, error correction processing can be performed without making any changes to transmission data generated by a protocol used in a higher layer such as a data link layer and a network layer. Thus, even if an error occurs between the data terminal 1 and the protocol terminating devices 5 and 6 and transmission data is lost, error-correction processing can be performed to obtain error-free data.

2: Operation of the First Embodiment As an example of the operation of the data communication system, a case where the data terminal 1 performs data communication with the network N2 via the protocol terminating device 5 will be described. FIG. 2 shows a protocol stack in this example. The data terminal 1 shown in FIG. 2 acts as a protocol termination point for the network layer and the data link layer, from which predetermined data is output. When this data is supplied to the protocol terminating device 5 via the mobile station 2, the protocol terminating device 1
Terminates the data link layer protocol,
In data communication with the network N2, a protocol of the data link layer is newly applied, but the protocol of the network layer is not terminated. Note that a similar protocol stack is applied when the data terminal 1 performs data communication with the network N3 via the protocol terminating device 6.

Therefore, in the network N1, there is no need to manage protocols used in the network layer. As a result, when the network layer is multi-protocol, it is not necessary to manage which protocol is used in the network layer, and it is not necessary to manage the data path information for each protocol. This allows the network N1 to use a plurality of protocols in the network layer without providing complicated hardware.

B. Second Embodiment The second embodiment is the same as the first embodiment except that one protocol terminating device is used and this protocol terminating device is arranged in the network N2. FIG.
It is a block diagram of a data communication system concerning a 2nd embodiment. 3, the configuration of each part is the same as that shown in FIG. Therefore, description of each configuration is omitted here, and the operation of the entire data communication system will be described with reference to FIG.

In the data communication of this example, a protocol is used in a data link layer, an X protocol and a Y protocol are used in a network layer, and a network N1 is used.
Within, a unique protocol shall be used. The data terminal 1 sets which protocol is used in the network layer by negotiation with a communication partner, and generates data according to the protocol. For example, if the X protocol is used in the network layer, the data DN
_{If X} is generated and Y protocol is used, data D
N _Y is generated. Thereafter, the data terminal 1 generates data DR _Xa , DR _Ya for the generated data DN _X , DN _Y using the a protocol of the data link layer, and outputs these to the mobile station 2.

The mobile station 2 generates data D _X and D _Y for the data DR _Xa and DR _Ya using a unique protocol used between the mobile station 2 and the base station 3. Incidentally, a large number of mobile stations are connected to the base station 3 in addition to the mobile station 2. Therefore, the generated data D _X , D _Y so that the base station 3 can recognize that the data is from the mobile station 2.
Contains an identifier ID1 indicating the identification number of the mobile station 2.

The data D _X and D _Y thus generated are supplied to the relay station 4 via the base station 3. For data transmission from the mobile station 2 to the relay station 4, for example, a well-known packet multiplex communication system is used. Data D _X, D _Y relay station 4
, The relay station 4 terminates its own protocol to generate data DR _Xa and DR _Ya and outputs them to another network N2 via a communication line. Then, when the data DR _Xa and DR _Ya are supplied to the protocol terminating device 5, the protocol terminating device 5 terminates the protocol a of the data link layer. In this case, the protocol terminating device 5 does not terminate the X protocol and the Y protocol used in the network layer, and performs data DN _X and data DN _Y without termination.
Generate

As described above, according to the present embodiment, the data terminal 1 and the protocol terminating device 5 terminate the data link layer, but do not terminate the higher layer. Therefore, there is no need to manage the types of protocols such as the X protocol and the Y protocol used in the network layer in the network and the routing information for each protocol. As a result, a multi-protocol can be applied to a network layer or the like higher than the data link layer. Since the protocol terminating device 5 is arranged in another network N2, it is not necessary to terminate the protocol in the data link layer in the network N1, and the configuration can be simplified.

C. Third Embodiment The third embodiment is similar to the first embodiment except that protocol termination devices 5 ′ and 6 ′ are used instead of the protocol termination devices 5 and 6.
This is the same as the embodiment. FIG. 4 is a block diagram of a data communication system according to the third embodiment. In the data communication of this example, a protocol and b
Protocol, X protocol and Y at the network layer
A protocol is used, and a unique protocol is used in the network N1. FIG. 4 differs from FIG. 1 in the protocol terminating device 5 ′ and the protocol terminating device 6 ′, and this point will be described. Neither of the protocol terminators 5 ′ and 6 ′ terminates the network layer protocol, but the protocol terminator 5 ′ terminates the data link layer a protocol and the protocol terminator 6 ′ terminates the data link layer b protocol. Terminate.

Next, the operation of the data communication system according to the third embodiment will be described with reference to FIG. The data terminal 1 sets which protocol is used in the network layer by negotiation with a communication partner, and generates data according to the protocol. For example, if the X protocol is used in the network layer, data DN _X is generated, and if the Y protocol is used, data DN _Y is generated.
Is generated. Here, if the a protocol and the b protocol are applied to the data DN _X and DN _Y at the data link layer, the data terminal 1 generates the data DR _Xa using the a protocol for the data DN _X , Data DR _Y
It generates data DR _{Y b} with b protocol to, and outputs them to the mobile station 2. However, the data terminal 1
Which protocol is used in the data link layer is registered in the network N1 in advance. In this example, a
The protocol and the b protocol are registered in the network N1. Further, the data terminal 1 can select which protocol is to be terminated in the data link layer, and the instruction terminates the protocol in the data link layer in one of the protocol terminating devices 5 ′ and 6 ′.

The mobile station 2 generates data D _X and D _Y for the data DR _Xa and DR _Yb by using a unique protocol used between the mobile station 2 and the base station 3. Note that the generated data D _X and D _Y include an identifier ID1 indicating the identification number of the mobile station 2. Data D _X, D _Y is
When via the base station 3 is supplied to the relay station 4, the data DR _Xa relay station 4 terminates its own protocol, generates a DR _Yb, another network N through which a communication line
2, and output to N3. Then, when the data DR _Xa and DR _Yb are supplied to the protocol terminating devices 5 ′ and 6 ′, respectively, the protocol terminating device 5 ′ terminates the a protocol of the data link layer, and the protocol terminating device 6 ′ terminates the protocol of the data link layer. b Terminate the protocol.

As described above, according to the present embodiment, since the protocol terminating devices 5 'and 6' are arranged in the other networks N2 and N3, it is not necessary to terminate the protocol in the data link layer in the network N1. The configuration can be simplified. Further, since the protocol terminating devices 5 'and 6' can terminate different protocols with respect to the protocol of the data link layer, it is possible to use a protocol terminating device which terminates only a necessary protocol.

D. 2. Modifications The present invention is not limited to the above-described embodiments, and for example, various modifications as described below are possible. In the above embodiments, the protocol used in the data link layer is PPP (Point-to-Point Protocol).
A protocol having the property of a serial link such as l) may be used. PPP is a general-purpose protocol, and encapsulates and transmits data generated according to a higher-layer protocol, so that the upper layer can be made compatible with multiple protocols. Also, if the packet multiplex communication method is used in the physical layer, even if a protocol having the property of a serial link is used in the data link layer, data can be multiplexed and transferred in packets, thereby providing a data communication system with high transmission efficiency. can do. Furthermore, in this packet multiplexing communication system, if error correction data is added to transmission data encapsulated by PPP and the transmission order of the data is controlled to form a frame, error correction processing can be performed, and Can be transmitted.

In the third embodiment, the protocol terminating devices 5 'and 6' may terminate both the a-protocol and the b-protocol.
This means that the protocol terminating devices 5 and 6 in the embodiment are arranged in the other networks N2 and N3, respectively. Further, there may be a protocol that is commonly terminated by the protocol terminating devices 5 ′ and 6 ′. For example, network N
In the case where the a and c protocols are used in the data link layer of the network 2 and the b and c protocols are used in the data link layer of the network N3, the a and c protocols are set in the protocol terminator 5 ′.
What is necessary is just to terminate the protocol b and the protocol c by the protocol terminator 6 '.

In the first and third embodiments, two protocol terminators are used. However, the present invention is not limited to this, and it goes without saying that three or more packet terminators may be used. In the above embodiments, the OSI reference model has been described as an example of a protocol layer. However, the present invention is not limited to this, and any protocol may be used as long as a protocol hierarchized into at least three layers is used. Of course, it may be hierarchized. In this case, if there are a first layer, a second layer, and a third layer in order from the lower layer, the first layer is a layer corresponding to the physical layer, and the second layer is a layer corresponding to the data link layer. The third layer is a layer corresponding to the network layer.

[0028]

As described above, according to the present invention, the data link layer protocol is terminated by the data terminal and the protocol terminator, but the network layer protocol is not terminated. It is possible to provide a data communication system that can flexibly respond.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment according to a data communication system of the present invention.

FIG. 2 is a conceptual diagram showing an example of a protocol stack in the embodiment.

FIG. 3 is a block diagram of a data communication system according to a second embodiment.

FIG. 4 is a block diagram of a data communication system according to a third embodiment.

[Explanation of symbols]

N1 network (communication network, mobile communication network), 1 data terminal, 2 mobile station, 3 base station, 4 relay station, 5,
5 ', 6, 6' ... protocol terminator, N1 ... network (communication network, mobile communication network), N2, N3 ... network.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Katsushi Nakamura 2-10-1 Toranomon, Minato-ku, Tokyo Inside NTT Mobile Communication Network Co., Ltd.

Claims (8)

[Claims] 1. A data communication system having at least a first layer, a second layer, and a third layer in order from a lower layer of a protocol and performing data communication between a plurality of communication networks, wherein the data communication system is connected to the communication network. A data terminal for generating data to be transmitted, and the second terminal without terminating the third layer protocol.
A data communication system comprising: a protocol terminator for terminating a layer protocol. 2. A data communication system having at least a first layer, a second layer, and a third layer in order from a lower layer of a protocol and performing data communication between a plurality of communication networks including a mobile communication network, A data terminal for generating data to be transmitted, a mobile station connected to the data terminal, a base station for wirelessly communicating data with the mobile station in a predetermined area, and a relay station for performing data communication with the base station The mobile communication network comprising: the second layer without terminating the third layer protocol;
A data communication system comprising: a protocol terminator for terminating a layer protocol. 3. A data communication system in which the protocol terminating device connected to the relay station is arranged in the mobile communication network, wherein data communication is performed between the data terminal and the protocol terminating device. The data communication system according to claim 2, wherein the first layer uses a packet multiplex communication system having an order control function. 4. The data communication system according to claim 3, wherein packet multiplex communication is performed by wire between said base station and said protocol terminating device. 5. The data communication system according to claim 2, wherein said protocol terminating device is arranged in said communication network other than said mobile communication network. 6. A data communication system in which at least two of the protocol terminating devices are arranged in the communication network, wherein one of the protocol terminating devices terminates at the other of the protocol terminating devices. The data communication system according to any one of claims 1 to 5, wherein a different protocol is terminated. 7. The data communication between the data terminal and the protocol terminating device, wherein the protocol of the second layer uses a property of a serial link. Any one of
A data communication system according to item 9. 8. The first layer is a layer corresponding to a physical layer of the open system interconnection reference model, and the second layer is a layer corresponding to a data link layer of the open system interconnection reference model. The data communication system according to any one of claims 1 to 7, wherein the third layer is a layer corresponding to a network layer of the open system interconnection reference model. .