JPS61189742A - Communication system - Google Patents

Abstract

PURPOSE:To simplify the constitution of a communication system by providing an exclusive relaying station to an LAN. CONSTITUTION:A massage delivered from the application layer A of a station ST.A is shifted successively among the layers of a protocol P1 and transmitted onto the LAN 1 through a physical layer P. In such a case, a proper header is provided to each layer. The packet transmitted on the LAN 1 is received by an address station set on the same LAN 1 based on the address information serving as the header of a data link layer D. Here the address station is treated as a relaying station ST.G. The packet delivered to the network layer N' of the protocol P2 of the station ST.G undergoes the check for the LAN name of an address through the header of a network layer N. Then the routing is carried out to a protocol P4 so that the transfer of data is carried out according to the address LAN through an exclusive circuit network NET2 or a public circuit network NET1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to data communication between LANs, and more particularly to a communication system that allows data communication to be performed across different types of line networks.

Disaster Skin 4 Conventionally, when communication is performed across a public line network (packet network) and a dedicated line network, there is a first dedicated stage scene that sends data to the public line network, and a first dedicated stage scene that sends data to the private line network. A second dedicated station for sending data is separately provided, and when a station connected to the dedicated line network attempts to send data to a station connected to the public line network, the data is sent to the destination station via the first dedicated station. When attempting to transfer data to the destination station or to communicate between stations connected to the dedicated line network, the data is transferred to the destination station via a second dedicated station.

For example, in a network configuration as shown in Figure 5,
From station 5T-A in LANI to station 5T- in LAN2 via public line network NET1
When data is transferred to B, the first dedicated station 5T-R for the public line network is used as a relay, and data is transferred from station 5T-A on LAN1 to station 5T-C on LAN:3 via dedicated line mNET2. When performing this, the second dedicated station 5T-8 for the dedicated line network is used as a relay.

However, if dedicated stations for relaying each of the public line network and the private line network are separately provided to perform communication across different types of line networks, the system configuration becomes complicated.

The present invention has been made in consideration of the above points, and the present invention has been made in consideration of the above points. The present invention provides a communication system that can communicate with any station connected to a line network.

In order to achieve the above object, the present invention provides a method for communicating between stations connected to each LAN via a public line network or a private line network across a plurality of LANs.
A dedicated relay station is set up in the relay station, and the relay station transmits information from the destination station to the L to which it belongs.
After determining whether the line network connected to the AN is a public line network or a private line network, data is sent to the determined line network.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a case where the present invention is applied to a network configuration corresponding to FIG.
When data is transferred to station 5T-B in AN2, and station 5 in LANI
In either case, when data is transferred from T-A to station 5T-C on LAN3 via dedicated line network NET2, data is transferred to the other party's dedicated station 5T-R via relay station 5T-G dedicated to LANI. Alternatively, data transfer is relayed between the 5T-8 and the 5T-8.

FIG. 2 shows an example of the protocol configuration of each station corresponding to the network configuration of FIG. 1. Stations 5T-A, 5T-B, and 5T-C each have an application layer A, a session layer S, a transport layer T,
Network layer N.

It has the same protocol P1 consisting of a data link layer and a physical layer P. Relay station 5T-G uses protocol P2. P3. It has P4. protocol P
2 consists of a transport layer T, a network layer N/, a data link layer and a physical layer P, and the network M
Compared to the network layer N, N' has additional means for exchanging data with the data link layer d' of protocol P4. Protocol P3 is for communicating via a public line network (packet network), and consists of a packet layer n, a data link layer d, and a physical layer p. Protocol P4 is for communication via a dedicated line network, and consists of a data link layer d' and a physical layer p'. The exclusive station 5T-R uses protocol P3. It has P5. Protocol P5 is
It has exactly the same configuration as the lower four layers of Pl. The dedicated station 5T-3 uses protocol P4. It has P6.

Protocol P6 has exactly the same configuration as the lower three layers of Pl. Also, between the transport layer T of the protocol P2 and the packet layer n of the protocol P3 at the relay station 5T-G, and between the transport layer T of the protocol P5 and the packet layer n of the protocol P3 at the exclusive station 5T-R.
A data conversion unit C0NV with bidirectionality is provided between the packet 5n and the packet 5n.
1.

C0NV2 are provided respectively.

A message issued from the application layer A of the station 5T-A is passed one after another between the layers of the protocol P1 and is transmitted from the physical layer P to the LANI. At this time, a unique header is attached to each layer. L
A packet transmitted on the ANI is received by a destination station on the same LANI based on destination information, which is a header of the data link layer. Here, it is assumed that the destination station is handled as relay station 5T-G.

Next, protocol P at relay station 5T-G
The packet passed to the network NN' of 2 is checked for the destination LAN name from the header of the network layer N, and is sent to the protocol P4 for data transfer via the private line network NET2 or the public line network NET1 according to the destination LAN. Routing is performed.

In other words, the destination LAN is a dedicated line, It! INET
If the LAN 3 is connected to the dedicated station 5T-3, the packet is passed to the data link layer d' in the protocol P4, and transferred to the protocol P4 of the dedicated station 5T-3 from the dedicated line network NET2 via the physical layer p'. The transferred packet is passed to the protocol P6 of the dedicated station ST/S, which is the destination of the data link layer d', and connected to the LAN.
B and will be received by application 212 layer A's destination station 5T-C.

Furthermore, if the destination LAN is LAN2 connected to public line network NET1, the packet is passed to transport layer T and then protocol P3 within the same station.
However, due to the difference in protocols between the transport NT and the packet layer n, the packet cannot be given as is, so the data converter C
0NV 1 converts the packet sent from the transport layer T so that it can be received by bucket l and layer n.

The translated packet is the physical Np of protocol P3.
The data is transferred from the public line network NET1 to the protocol P3 of the dedicated station 5T-R, which is the destination of the data link layer d, and received. The received packet is passed to the packet layer n, subjected to reverse data conversion to that described above in the data converter C0NV2, and then provided to the transport layer T of the protocol P5. The packet is physical layer P
The signal is transmitted from LAN 2 to station 5T-H, which is the destination of application layer A, and received by station 5T-H.

In addition, from station 5T-B to station 5T-A
and from station 5T-C to station 5T-
When data is transferred to A, the same procedure as described above is used. In this case, each data conversion unit C0NVL,.

The data conversion in C0NV2 will be performed in the opposite direction to the previous case. Each data converter C
For data conversion in 0NVI and C0NV2, known protocol conversion technology is used as is.

In order to carry out the above communication, the network layer N' in the protocol P2 of the relay station 5T-G is connected to the line network NE to which each LAN is connected, as shown in FIG.
It has a management table to clarify T. The management table.

It is written in a part of the memory area allocated to the network layer N' of one memory included in the relay station 5T-G. One of the management tables is shown in the same figure (a).
As shown in the figure, each LAN connected to the public line network NETl
The other one is Table 1, in which names are registered, and the other one is Table 2, in which names of each LAN connected to the dedicated line network NET2 are registered, as shown in FIG. 2B. Same L
When relay station 5T-G receives a packet sent from station 5T-A in AN1, it determines which one in Tables 1 and 2 matches the destination LAN name in network layer header H shown in FIG. Search for the
If it is in table l, the packet is passed below the transport layer so that the data is transferred via the public line wINET1, and if it is in table 2, the data of protocol P4 is sent to be transferred via the private line network NET2. The packet is passed to the link layer d'.

The management table shown in FIG. 3 can be created by inputting the LAN name from the console installed in the relay station 5T-G, storing it as a file in a magnetic disk device, etc. The file may be read out and loaded into the predetermined area of the memory mentioned above.

Group leader Above is the communication system according to the present invention.

It is now possible to communicate with stations connected to either the public line network or the leased line network using a single relay station, without having to separately provide dedicated stations for relaying each of the public line A network and the leased line network as in the past. This makes it possible to simplify the system configuration, and
It is no longer necessary for the station transmitting data to determine whether the destination station is connected to a public line network or a private line, and the software at each station is effectively simplified to enable high-speed data transfer. It has the excellent advantage of being able to

[Brief explanation of drawings]

FIG. 1 is a simplified diagram showing an example of a network configuration when a communication system according to the present invention is applied, FIG. 2 is a block diagram showing an example of a protocol configuration of each station in the same network configuration, and FIGS. ) is a diagram showing a LAN management table for each public line network and private line network, respectively, FIG. 4 is a diagram showing an example of the configuration of a network layer header, and FIG. 5 is a simplified diagram showing a conventional network configuration.

Claims (1)

[Claims] Each LAN is connected via different line networks between LANs.
In a device that allows data communication to be carried out between stations connected to a LAN, a relay station provided exclusively for the LAN is used to transfer data from the destination of data sent from a station on its own LAN to the LA to which the destination station belongs.
A communication system comprising means for determining the type of line network connected to N, and means for transmitting data to the line network according to the determined type.