JPS63200628A - Method and apparatus for mutual connection - Google Patents

Abstract

PURPOSE:To prevent the deterioration of line quality by providing a logical link corresponding to a ground station being an opposite destination to apply error control. CONSTITUTION:In applying mutual connection between local area networks (LAN) utilizing the multi-access performance and the broadcast performance of a satellite, a logical link is provided corresponding to the opposite ground station to apply error control. For example, a mutual connection device 30 has a logical link controller 105 comprising plural logical link control circuits 117-120 corresponding to a station address, the circuits 117-120 are connected to one of the plural logical link control circuits 117-120 of the opposite destination station logically to apply error control between them. Thus, the line quality is guaranteed and the mutual connection between LANs with excellent line quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an interconnection method and an apparatus therefor, and particularly to an interconnection method for interconnecting a plurality of widely distributed local area networks using satellite lines. and its apparatus.

[Conventional technology]

Satellite links can be used to interconnect multiple local area networks distributed over a wide area.

FIG. 4 is a conceptual diagram showing interconnection between local area networks using satellites, where 50 is a satellite, 21 is a transmitting/receiving device in each local area network, and 2
0 is a terminal, 22 is a computer, and 41 to 4
3 indicates the transmission information from each ground station, and 51 indicates the satellite 5
It shows the transmission information starting from 0.

When a satellite line as shown in FIG. 4 is used to interconnect local area networks (hereinafter referred to as LAN), the conventional system simply replaces the terrestrial dedicated line with a satellite line. Therefore, there are two types of connections: a ring connection as shown in Fig. 5, and a ring connection as shown in Fig. 5.
As shown in the figure, there are some that are connected in a mesh pattern.

The one in Figure 5 is a configuration where eight LANIs are connected in a ring shape using satellite line 2, and the one in Figure 6 is a configuration in which eight LAN1s are connected in a mesoche configuration. .

By the way, in the above-mentioned ring-shaped connection method, communication between terminals requires several satellite hops, resulting in a large delay. On the other hand, in the method of connecting in a mesh pattern, only one hop is required, but the interconnection equipment requires a packet switching function, and as the number of satellite links increases, line settings become complicated. Problems arise such as the transmission rate being high (unable to obtain).

Therefore, the applicant has developed an interconnection method between LANs that utilizes the multi-access and broadcast characteristics of satellites.

In other words, the satellite line has multi-access properties that allow any station to access the satellite, and broadcast properties that allow any station to receive signals from the satellite.
Taking advantage of this, it is possible to perform mesh-like communication, which adds the destination ground station address to packets on the LAN and sends them to the satellite line, receives all packets from the satellite line, and then sends them to the satellite line. This is a method of interconnection by checking the station address and, if it is the own address, fetching it and sending it to the LAN. When there are multiple LANs, it is possible to interconnect between the LANs by effectively utilizing the multi-access and broadcast characteristics unique to satellite lines. connection can be made.

[Problem that the invention seeks to solve]

However, unlike a LAN, the quality of the satellite link deteriorates depending on the weather. Furthermore, in this case, the above-mentioned mesh-like communication form utilizing multi-access and broadcast properties cannot directly utilize the point-to-point error H control used on the ground.

The purpose of the present invention is to utilize the multi-access nature and broadcast nature of satellites, and to guarantee the deterioration of line quality.
An object of the present invention is to provide a method for interconnecting between N and a device thereof.

[Means for solving problems]

The interconnection method of the present invention adds a destination ground station address to a local area network packet and sends it to the satellite line, receives the packet from the satellite line, checks the ground station address, and if it is the address of the own station. This is an interconnection method that captures the packets and sends them to the local area network, and is characterized by establishing a logical link to the destination ground station and performing error control.

Furthermore, the interconnection device of the present invention is an interconnection device between local area networks that utilizes the multi-access and broadcast characteristics of satellites, and includes a correspondence table between the terminal address and the station address of the ground station to which the terminal belongs. When a packet is received on the local area network and the destination address of the packet matches the terminal address in the address table, the packet is discarded if it is the own address. , an address filter for capturing the address of another station, and a plurality of logical link control circuits corresponding to the station address, and this logical link control circuit is connected to one of the plurality of logical link control circuits in the other station. It is characterized by comprising a logical link controller that is logically connected and performs error control, and an access controller that accesses output packets of the logical link controller onto a local area network.

[Effect]

The present invention is an interconnection method between LANs that utilizes the multi-access and broadcast properties of satellites, in which a logical link is established to correspond to a destination ground station, and error control is performed.

This method of interconnection between LANs adds destination ground station addresses to LAN packets and sends them to the satellite line.On the other hand, when receiving, all packets from the satellite line are received, but the packets are not included in the ground station address. Since an address is attached, the LAN checks the ground station address, and if it is the local station's address, it is retrieved and sent to the LAN.The satellite line has multi-accessibility that allows access to the satellite from any station, Any station can receive broadcast signals from satellites and perform mesh-like communication, but in this case, in order to maintain the line quality of the satellite line, which is easily affected by the weather, By establishing a logical link to correspond to the destination ground station and performing error control, error control is possible even in a mesh-like communication form that utilizes such multi-access and broadcast properties.

Specifically, the interconnection device can realize a logical link controller consisting of a plurality of logical link control circuits corresponding to station addresses.

Each logical link control circuit is logically connected to one of the multiple logical link control circuits in the other station, and line quality is guaranteed by performing error control between them. Interconnection becomes possible.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In this embodiment, the LAN is assumed to be a bus-type LAN in which the terminals 20 are connected to a 1° coaxial line. An interconnection device 3o is connected to this coax 10 in the same way as the terminal 2°.

As shown in FIG. 1, this interconnection device 30 includes a first address filter 105, an address table 106, a divider 107, a second address filter 103,
It has an assembler 102, an access controller 101, and a logical link controller 108, which is connected between the coaxial 1o and the time division access (TDMA) controller 40.

Before the first address filter 105, an address filter 105 that takes in packets flowing on the coax 10 is provided.
A receiver 104 is provided for sending the packet to the coaxial 1o, and a driver 100 is provided downstream of the access controller 101 for sending assembled packets to the coaxial 1o as described later.

The first address filter 105 is an address filter that receives packets on the LAN and captures predetermined packets. The address table 106 has a correspondence table between the terminal address and the station address of the ground station to which the terminal belongs, and the first address filter 105 detects when the destination address of the packet matches the terminal address in this address table 106. Look at the station address, and if it is your own address, discard the packet, and if it is another station's address, take in the packet.

The logical link controller 108 has a plurality of logical link control circuits corresponding to the above-mentioned station addresses, and the logical link control circuit is logically connected to one of the plurality of logical link control circuits in the destination station, A concrete example of the control means is shown in FIG.

This logical link controller 108 includes a swifter 111 connected to an address filter 105, a switching control circuit 112, and a buffer 1 connected to a divider 107.
21, a buffer 115 connected to the assembler 102,
It includes a swifter 113 connected to this buffer 115, a switching control circuit 114, and a buffer 110 connected to the access controller 101, as well as a plurality of logical link control circuits 117 to 120.

Logical link control circuit 117 ~ by switch 111
120 is controlled by the switching control circuit 112 and the connection control circuit 11 by the switch 113.
7 to 120 are controlled by the switching control circuit 114.
The switching of the former is performed using address table 1.
The latter switching is performed in response to the station address sent from the assembler 102, and in response to the source address of the output packet from the assembler 102, as will be described later.

In this way, the interconnection device 30 includes the logical link controller 108, and the logical link controller 10B includes a plurality of logical link control circuits 117 to 120.
has. The other LAN sides have a similar configuration; each logical link control circuit is logically connected to one of the multiple logical link control circuits in the other station, and error control is performed between them to ensure line quality. guarantee.

The divider 107 includes a logical link controller 108
The output of the logical link control circuit is given via the buffer 121. This divider 107 divides the packet taken in by the address filter 105 and sent through the logical link controller 10B into predetermined lengths, adds a station address to each divided part, and outputs it. The output of 107 is sent to a time division access controller 40 which sends out the divided packets in station defined time slots.

A signal from a satellite enters the second address filter 103 via the time division access controller 40 . This address filter 103 is an address filter that looks at the destination station address of the received fragmented packet, takes in the packet if it belongs to its own address, and discards the other packets, and its output is fed to the assembler 102. It will be done.

The assembler 102 restores the divided packets to the original packets, and the packets assembled and restored by the assembler 102 are sent to the logical link controller 108.
The data is sent to the buffer 115 of the switch 113, and further supplied to the access controller 101 through the buffer 110 via the logical link control circuit connected by the switching control of the switch 113. The access controller 101 is a means for accessing the restored packet obtained as the output packet of the logical link controller 108 on the LAN, and is sent out at the timing of access.

In this way, in a device that interconnects LANs using the multi-access and broadcast characteristics of satellites, packets on the LAN are received and the address table 106 is a correspondence table between the terminal address and the station address of the ground station to which the terminal belongs. Then, by looking at the station address where the destination address of the packet matches the terminal address in the address table 106,
An address filter 105 that discards the packet if it is the address of the own station and takes in the packet if it is the address of another station, and a plurality of logical link control circuits 1 corresponding to the above-mentioned station addresses.
17 to 120, the logical link controller 108 is logically connected to one of the plurality of logical link control circuits in the destination station and performs error control, and the logical link controller 108 The access controller 101 accesses the output packets of the LAN on the LAN.

The interconnection according to this embodiment will be explained in more detail with reference to FIG.

First, FIGS. 3(a) to (C) show the logical link control circuit output, the divider 107 output, and the frame format of the satellite line. In FIG. 3, DSA is the destination station address, and SSA is The source station address, LLC represents the logical link controller field, and F represents the frame synchronization signal.

Now, when communicating using a satellite line, the interconnection device 3
0, packets flowing on the coax 10 are taken in through the receiver 104 and sent to the next address filter 105. The address filter 105 compares the destination terminal address in the packet header with the list of terminal addresses in the address table 106, and if the station address corresponding to the matching terminal address is the address of another station, it is sent to the logical link controller 108, and the address of the own station is sent. If so, throw it away there.

Therefore, only the address of the other station will be sent to the transmitter via the logical link controller 108, divider 107, and time division access controller 40, as will be described later.

In addition, the address table 106 has a correspondence relationship between the terminal address and the station address of the ground station to which the terminal belongs, as shown in the following table, and the above-mentioned processing uses this. It will be done.

The address table, that is, the address table 106, as shown in the table above, is a pair of a terminal address and the station address of the ground station to which the terminal belongs, and the station address that is paired with the terminal address that matches the packet header is If it is from another station, the packet is sent to the logical link controller 10.
8, and on the other hand, the address table 106 notifies the verbal link controller 108 of the station address. As described above, the logical link controller 108 includes a plurality of logical link control circuits, and each logical link control circuit is logically connected to one of the plurality of logical link control circuits in the partner station, and performs error control and guarantees line quality. That is,
When the address filter 105 captures a packet whose station address is another station and sends it to the logical link controller 108, the address filter 105
The packets passing through are sent to the logical link control circuit connected by the switch 111. In this case, switch 11
1 connection control is performed by a switching control circuit 112, and the switching control circuit 112 performs switching control in accordance with the station address sent from the address table 106.

Each of the logical link control circuits 117 to 120 is logically connected to one of a plurality of logical link control circuits in a partner station, and performs error control.

In this way, the logical link controller 108 has multiple logical link control circuits 11 corresponding to the station addresses.
7 to 120, which perform error control. The outputs of the logical link control circuits 117 to 120 are sent to the buffer 12.
1 to the divider 107 in FIG. Divider 1
07, the output packet of the buffer 121 in FIG.
As shown in the figure, the time division access controller 40 divides the time slots into lengths determined by the time slot length, and adds a destination station address to each slot. The output of the divider 107 is sent to the time division access controller 40 where it is controlled to be sent in the time slot assigned to that station and sent to the transmitter.

In this way, each LAN communicates with other LANs using the satellite line.

Next, reception from another LAN will be explained.

The signal received by the receiver from the satellite passes through the time division access controller 40 and enters the interconnection device 30. In the interconnection device 30, the output from the time-sharing access controller 40 is first received by the address filter 103, and
Check the destination station address here, and if it is your own station address, take it in, otherwise discard it.

Therefore, in each LAN, only those with their own station address are connected to the assembler 102 and the logical link controller 10.
8, it will be sent to the coax 10 via the access controller 101 and driver 100.

When the own station address is taken in by the address filter 103, it is restored by performing the reverse process of the above-described division performed in the transmitting side LAN.

That is, the next assembler 102 assembles the divided LAN packets. The assembled packet is sent to logical link controller 108. The output of the assembler 102 is sent through a buffer 115 in FIG. 2 to a logical link control circuit connected by a switch 113. Connection control of the switch 113 is performed by a switching control circuit 114.

The switching control circuit 114 looks at the source address of the packet as it passes through the buffer 115, and switches the switch 1 to the switch 1.
Controls 13. This allows a one-to-one correspondence between the logical link control circuit of the local station and the logical link control circuit of the opposite station. Logical link control circuit 11
Output packets 7 to 120 are sent through buffer 110 to access controller 101 in FIG. The sent packet is timed to access the coax 10 by the access controller 101, and is transmitted to the coax 10 through the driver 100.

In this way, it is possible to interconnect multiple LANs by effectively utilizing the multi-access nature of the satellite line, which allows any station to access the satellite, and the broadcast nature, which allows any station to receive signals from the satellite. , it does not cause large delays like conventional methods, and it also does not cause problems such as complicated line settings or difficulty in achieving a high transmission rate per link as the number of links increases. With a propagation delay of

In other words, it is an interconnection that adds the destination ground station address to the LAN packet and sends it to the satellite line, receives all packets from the satellite line, checks the ground station address, takes it in if it is the address of the own station, and sends it to the LAN. In this method, a logical link is established to correspond to the destination ground station and error control is performed, so even if the communication form is a mesh-like communication that takes advantage of the multi-access and broadcast characteristics of the satellite, the line quality may vary depending on the weather. It is possible to perform error control on satellite links that are affected by traffic conditions, and to guarantee link quality.

〔Effect of the invention〕

As explained above, the present invention makes effective use of the multi-access and broadcast characteristics unique to satellite lines to create a LAN.
To enable interconnection between LANs with good line quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the logical link controller of FIG. 1, and FIG. 3 is a block diagram showing an example of the logical link controller of FIG. Figure 4 is a conceptual diagram showing interconnection between local area networks (LAN) using satellites, Figure 5 is a diagram showing a form in which local area networks are connected in a link form, Figure 6 1 is a diagram showing a form in which local area networks are connected in a mesh pattern. 10... Coaxial 20... Terminal 30... Interconnection device 40... Time division access controller 100
...Driver 101 ...Access controller 102 ・
...Assembler 103, 105 ...Address filter 104
...Receiver 106 ...Address table 107 ...
・divider

Claims (2)

[Claims] (1) Add the destination ground station address to the local area network packet, send it to the satellite line, receive the packet from the satellite line, check the ground station address, and if it is your own station address, send the packet. An interconnection method that takes in data and sends it to a local area network, which is characterized by establishing a logical link to a destination ground station and performing error control. (2) An interconnection device between local area networks that utilizes the multi-access and broadcast characteristics of satellites, which includes an address table that corresponds between terminal addresses and the station addresses of the ground stations to which the terminals belong, and a local area network. receive packets on the network,
An address filter that looks at the station address where the destination address of the packet matches the terminal address in the address table, discards the packet if it is the address of the own station, and captures the packet if it is the address of another station; A logical link controller that has a plurality of corresponding logical link control circuits, this logical link control circuit is logically connected to one of the plurality of logical link control circuits in the destination station, and performs error control; An interconnection device comprising: an access controller that accesses output packets of the link controller onto a local area network.