JP2888371B2 - Communication control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication network system having a full-duplex transmission path, in which a terminal sends a forward signal including a destination address and receives a response signal from the destination terminal to perform communication. The present invention relates to a communication control device for performing communication.

2. Description of the Related Art Conventionally, there are various communication networks of this kind.
As one of them, a multi-channel grid communication network based on an analogy of a living nerve cell is disclosed in JP-A-63-74349 and JP-A-2-29046. This is achieved by connecting a communication control element of a multi-input one-output signal as a node to a multi-coupling structure to form an irregular communication network (LADERNET = Lattice).
Each node has a communication network form in which digital signals are transferred on a first-come, first-served basis.

Although this grid communication network has many advantages, it is particularly excellent in the following points. One is that the degree of freedom of the network topology is high due to the multi-coupling structure. Therefore, the fault tolerance (fault tolerance) is high.
That is, even if there is a failure in a part of the network, communication is appropriately secured on another route. Second, an optimal communication path (shortest path) is selected for each communication by first-come-first-served logic.
Further, this system adopts a multi-channel system in which a plurality of connection channels are simultaneously established in a node, and efficiently establishes full-duplex communication. Thus, the present system is effectively applied to, for example, the physical layer of OSI (Open System Interconnection).

Problems to be Solved by the Invention Here, when considering network integration, Ethernet
Network integration using relay devices such as data link bridges and gateways compatible with CSMA / CD communication protocols represented by (Ethernet) and Starlan (Starlan) has become mainstream. Here, if a data link bridge is to be applied to a LAN such as the irregular communication network formed by a full-duplex transmission line, since it does not have a unique address, a countermeasure is required. .

For example, if a terminal transmits to another terminal in the same network, the response signal from the data link bridge may arrive earlier than that from the target terminal. And the path is fixed, and communication with the target terminal cannot be performed. That is, there is a problem in operation with a normal terminal. In consideration of this point, as a data link bridge compatible communication control device, the maximum one-way transmission delay time of the network is T _PMAX, and the communication control device for the terminal starts receiving and starts transmitting the response signal. When the time is T _A , the predetermined period until the response signal is transmitted is (T _A +2
* T _PMAX ) has been proposed by the present applicant. This is when the signal from the network is received, it has to be sent the response signal after a predetermined time T _R to be a broadcast signal (provided that _{T R> (T A +2 ·} T PMAX)) Things.

Such a data link bridge-compatible communication control device is capable of setting a physical dedicated communication path (fixed path) between a calling terminal and a destination terminal, such as an irregular communication network as described above. And disadvantages when there are two or more data link bridges in the same network.

This will be described with reference to FIG. The illustrated example shows an example in which three networks 1, 2, 3 are integrated by four communication controllers 6, 7, 8, 9 using two data link bridges 4, 5. In the illustrated example, for example, if one of the terminals belonging to the network 1 (this is referred to as terminal A) starts transmitting to a terminal belonging to the network 2 (this is referred to as terminal B), this signal is Received by both data link bridges 4 and 5. Then, both the data link bridges 4 and 5 send a response signal. At this time, the terminal A is located closer to the data link bridge 5 than the data link bridge 4 and the response from the data link bridge 5 is returned. Arrives at the terminal A earlier, a communication path is formed between the terminal A and the data link bridge 5. Therefore, a signal cannot be sent to the intended destination terminal B.

Means for Solving the Problems A communication having a full-duplex transmission path, in which a transmitting terminal transmits an outgoing signal including an address of a destination terminal and receives a response signal confirming the address from the destination terminal to perform communication. In a communication control device for a data link bridge of a network, a storage unit for storing addresses of all terminals belonging to a communication network on the side of the data link bridge connected as viewed from the self, and a destination address in a signal received from the communication network, An address comparing unit that compares the addresses of all the terminals stored in the storage unit; and a response signal output unit that transmits a response signal when the comparison result has at least one matching address. The response signal transmitting means is based on the collision detection signal when the reception of the signal from the data link bridge and the reception of the signal from the communication network occur simultaneously. An operation control unit for stopping or immobilizing the operation is provided.

Action The addresses of all the terminals belonging to the communication network on the side of the data link bridge connected as viewed from the self are stored, and the destination addresses in the signals received from the communication network are the addresses of all the terminals stored in the storage unit. When the destination address in the received signal matches at least one of the stored addresses, a response signal is transmitted. Therefore, even if a plurality of data link bridges exist in the same communication network, the response signal is transmitted. Is returned, and communication with a desired destination terminal can be performed. Therefore, the degree of freedom in constructing a communication network is expanded.

At this time, if a collision occurs in the reception of the signal, the operation of the response signal transmitting means is stopped or immobilized, so that erroneous address comparison, storage, and response signal transmission can be prevented.

Embodiment An embodiment of the present invention will be described with reference to the drawings.

First, the basic concept of this embodiment will be described with reference to FIG. The communication control device for the data link bridge stores the addresses of all the terminals belonging to the network of the other party as seen from the self. For example, in the illustrated example, the communication control device 6 corresponds to the network 2, the communication control device 7 corresponds to the network 3, the communication control device 8 corresponds to the networks 1, 3, and the communication control device 9 corresponds to the networks 1, 2. The addresses of all the terminals (not shown) to which the terminal belongs are stored. When a signal is received from an arbitrary network, the destination address contained therein is compared with all the addresses stored in its own communication control device, and if there is a match, a response signal is returned. Things.

A configuration of a communication control device (any of 6 to 9) for realizing such a basic idea will be described. Here, all of the networks 1 to 3 shown in FIG. 3 are the above-mentioned irregular communication networks, and the communication means is Ethernet. FIG. 2 schematically shows the response signal transmitting means 10 and its related parts in the configuration of the communication control device.
The illustrated example relates to, for example, the communication control device 6.
First, the differential transmission signal TTRM from the data link bridge 4
A receiver 11 for receiving T and converting it to a TTL level signal TD is provided, and a driver 12 for converting the converted signal TD into a differential signal NTRMT and outputting it to the network 1 is provided. On the other hand, conversely, the differential reception signal NR from the network 1
Receiver 13 that receives CV and converts it to TTL level signal RD
And a driver 14 for converting the converted signal RD into a differential signal TRCV and outputting the converted signal RD to the data link bridge 4. Further, a Manchester encoder decoder (ME) that converts the encoded signal TTRMT into an NRZ data signal T × D and a lock T × C synchronized with the NRZ data signal TxC and outputs the converted signal.
D) 15 are provided. The MED 15 affirms the signal TCSN while receiving the signal TTRMT, and when the signal TCSN is negated, the output of the driver 12 is turned off. Similarly, a Manchester encoder decoder (MED) 16 which converts the encoded signal NRCV into an NRZ data signal R × D and a clock R × D synchronized with the data signal R × D and outputs the converted signal
Is provided. The MED 16 affirms the signal RCSN while receiving the signal NRCV, and when the signal RCSN is negated, the output of the driver 14 is turned off.

Further, a selector 17 for selecting transmission / reception is provided. When the signal TCSN is asserted earlier than the signal RCSN, the selector 17 outputs the signals T × D and T × C to the data DA.
Output as TA and clock CLK. Conversely, when the signal RCSN is affirmed earlier than the signal TCSN, the signals R × D and R × C are output as data DATA and clock CLK.
Also, of the signal TCSN or RCSN,
Output as signal PEN. The output side of the selector 17 is connected to a preamble detection circuit 18 functioning as an operation control unit. The preamble detection circuit 18 outputs the signal PEN
Is started, the operation starts to detect the end of the preamble of the data DATA. That is, when the end of the preamble is detected, the signal PEND is affirmed.

The preamble detection circuit 18 is connected to an address comparison circuit 19 which is a feature of the present embodiment. As shown in FIG. 1, the address comparison circuit 19 includes a counter 20, an OR gate 21, an AND gate 22, a memory unit 23 serving as a storage unit, and a comparison unit 24 serving as an address comparison unit. First,
When the signal PEND is affirmed, the counter 20 counts the 48-bit clock CLK corresponding to the destination address following the preamble of the data DATA. When the counting is completed, the output Q is affirmed. The supply of the clock CLK to the memory unit 23 and the comparison unit 24 is controlled by the OR gate 21 and the AND gate 22. That is, when the data DATA is the signal R × D, it is output immediately after the end of the preamble, but when the data DATA is the signal T × D, it is output after the output Q of the counter 20 is affirmed. Simultaneously writing data DATA in the internal register in synchronism with the memory unit 23 the clock CLK, to already sequentially read out from the output Q ₁ Qn address information stored.
When the data DATA is the signal T × D, the output from the comparison unit 24
Store the contents of the register when MMTCH is affirmed.
The comparison unit 24 is the contents of the data DATA and the output of the memory unit 23 in synchronization with the clock CLK. At the same time sequentially compared with the Q ₁ ~Qn. If the data DATA is T × D and they do not match at all, the signal MMTCH is affirmed and the data DATA
In the case of × D, the signal MTCH is affirmed if at least one matches.

That is, the address comparison circuit 19 starts operation when the signal PEND is affirmed, and operates differently depending on whether the data DATA is T × D or R × D. Data DATA is T
In the case of × D, the source address in the signal is compared with all the addresses already stored, and if they match, the operation is terminated there, but if they do not match, it is considered that there is no registration. , The source address is newly stored. That is, the storage of the terminal addresses belonging to the network 2 on the side of the data link bridge 4 as seen from the self is automatically learned and registered from the signal transmitted from the data link bridge 4. Therefore, it is possible to automatically follow a change such as movement or exchange of a terminal in the network 2 without requiring any manual labor. On the other hand, data DATA
Is R × D, the destination address included in the received signal is compared with all the addresses already stored,
If there is a match, the signal MTCH is affirmed, and the operation of the response signal transmitting circuit 25 serving as a response signal transmitting unit is started. As a result, the response signal sending circuit 25 outputs the response signal RF and the signal RFEN affirming it. When the signal RFEN is affirmed, the MED 16 encodes the response signal RF, converts it into a differential signal, and outputs it. Therefore, if the destination address in the received signal matches at least one of the stored addresses, the response signal RF is sent out, and even if there are a plurality of data link bridges, the one including the terminal of the desired address is included. Only one data link bridge returns a response signal, and communication with a desired terminal is secured.

During reception of a signal from the data link bridge 4 (transmission to the network 1),
When the reception of a signal from the communication device occurs, it is necessary to avoid sending the response signal RF because this is a collision. Therefore, in this embodiment, when the collision detection signal is output,
Operation 10 is stopped or immobilized. That is, when the signal COL that is affirmed by the collision detection (for the collision detection itself, refer to the earlier publication) is input, the preamble detection circuit 18 is initialized, and the signal PEND and the signal MTCH are sequentially negated. Response signal detection means 10
The whole will be initialized. Therefore, when a collision occurs, erroneous address comparison and storage, and further, transmission of a response signal are prevented, and reliability is maintained.

Advantageous Effects of the Invention As described above, the present invention stores the addresses of all terminals belonging to the communication network on the side of the data link bridge connected from the viewpoint of the self, and stores the destination address in the received signal from the communication network. Since the response signal is sent out when the destination address in the received signal matches at least one of the stored addresses, the response signal is sent out. Even if there are a plurality of data link bridges in the network, only one response signal is returned, so that communication with a desired destination terminal can be performed, and therefore, the degree of freedom in constructing a communication network can be expanded,
Also, if a collision occurs in receiving a signal from the data link bridge and the communication network, the operation of the response signal transmitting means is stopped or immobilized, thereby preventing erroneous address comparison, storage, and response signal transmission. And high reliability.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a block diagram showing an address comparison circuit, FIG. 2 is a block diagram showing a response signal transmitting means and its periphery, and FIG. 3 is an example of the entire system configuration. FIG. 1-3 communication network, 4, 5 communication network, 10 response signal transmitting means, 18 operation control unit, 23 storage unit, 24 address comparison unit, 25 response signal transmission Department

Continuation of the front page (56) References JP-A-2-218235 (JP, A) JP-A-2-2737 (JP, A) JP-A 1-298831 (JP, A) JP-A 1-296830 (JP) , A) JP-A-1-129546 (JP, A) JP-A-1-122230 (JP, A) JP-A-1-153750 (JP, U) Ricoh Technicol Report No. 16, JAN, 1987, Takashi Yano, et al., "LAN with Multi-Coupling Distributed Architecture," pages, 80-83 IEICE Technical Report Vol. 154 (SE86-69) Takashi Yano et al., "Proposal of Local Area Network COMLAT with Combined Topology", pages. 31-36 (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12/28 H04L 12/46 JICST file (JOIS)

Claims (1)

(57) [Claims] A communication network having a full-duplex transmission path in which a transmitting terminal transmits a forward signal including an address of a destination terminal and receives a response signal confirming the address from the destination terminal to perform communication. A communication control device for the data link bridge, wherein a storage unit for storing addresses of all terminals belonging to the communication network on the side of the data link bridge connected as viewed from the self, and a destination address in a signal received from the communication network. Signal responding means having an address comparing unit for comparing addresses of all terminals stored in the unit and a response signal transmitting unit for transmitting a response signal when the comparison result has at least one matching address; The operation of the response signal sending means is stopped based on the collision detection signal when the signal from the link bridge and the signal from the communication network occur simultaneously. Communication control apparatus characterized in that a response signal transmitting unit having an operation control unit for the immobile.