JPH04242341A - Communication network controller - Google Patents

Abstract

PURPOSE:To prevent missing of a frame due to occurrence of collision and to quicken the return processing of a lobe medium test MAC frame by not sending the MAC frame sent from a terminal equipment for ring management to an indefinite form communication network. CONSTITUTION:A free token and a frame are identified at an input signal identification section 15 for an input signal from a TRN terminal equipment and further a MAC frame and a lobe medium test MAC frame in the MAC frame are identified. In the case of the MAC frame other than the lobe medium test frame, it is written in an FIFO 6 while being distinguished from other usual frame and read according to a command of a sequencer 14 and looped back to the TRN terminal equipment via an output selector 13 through a 1st loopback path 16 with priority over an input frame from an indefinite communication network. On the other hand, in the case of the lobe medium test frame, the frame is looped back to the TRN terminal equipment directly through the output selector 13 not via the FIFO 6 through a 2nd loopback path 17.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication network control device applicable to multimedia communication, typified by a local area network (LAN).

0002

2. Description of the Related Art There are various types of communication networks of this type, one of which is a multi-channel lattice communication network based on the analogy of biological nerve cells.
It is shown in Japanese Patent No.-74349. This is an amorphous communication network (LADERNET = Lattice) in which communication control elements of multiple input and output signals are connected to a multi-coupled structure as nodes.
eDynamic Architecture Net
The communication network is structured such that each node transfers digital signals on a first-come, first-served basis.

[0003] This grid-like communication network has many advantages, particularly in the following points. One is that the multi-connection structure provides a high degree of freedom in network topology. Therefore, fault tolerance is high. That is, even if there is a failure in a part of the network, communication can be properly secured through other routes. Second, the optimal communication route (shortest path) is selected for each communication based on first-come, first-served logic. Furthermore, this system uses a multi-channel method in which multiple connection channels are established at the same time in a node to efficiently establish full-duplex communication. Thus, the system is effectively applied, for example, to the physical and network layers of OSI (Open Systems Interconnection).

[0004] Also, as another network system,
Ring topology IEEE802.5 token
Ring network (TRN=Token ring
network). An overview of this TRN algorithm will be omitted, but it is important to note that all terminals are synchronized, that only terminals that have obtained a free token (in other words, a ticket indicating the right to transmit) can transmit, and that message information cannot be transmitted. It has excellent security features such as being able to return to the terminal and confirm that it was received correctly. It also has excellent throughput-delay characteristics during high traffic.

[0005] In the case of TRN, transmission cannot be started until the free token has made one circuit around the network, and the transmission waiting time tends to be long. Furthermore, the performance of TRN decreases as the system expands. That is, in a TRN, as the number of terminals increases, the time required for free tokens to come around increases, and at the same time, the traffic also increases, so the time becomes longer. Furthermore, the TRN suffers significant damage when the central ring fails, and has low fault tolerance. On the other hand, the above-mentioned amorphous communication network does not have an address concept, so to speak, it is a "cable with a predetermined algorithm," and it has the characteristics of a free protocol, so it can handle various protocols. terminals can be connected. Therefore, if the system is configured by connecting TRN terminals to the amorphous communication network, TR
It is expected that this will solve the drawbacks of N and open up the world of Token Ring networks that have the advantages of an amorphous communication network.

However, it is not possible to simply connect a TRN terminal to an amorphous communication network as it is, and at least an interface device is required that makes the amorphous communication network look like a LAN of the TRN protocol from the connected terminal.
Various devices for this purpose have been proposed by the applicant.

[0007]

[Problems to be Solved by the Invention] However, the TRN handles various frame signals, but when the MAC frame transmitted for ring management is sent from the TRN terminal onto the amorphous communication network, the MAC frame becomes amorphous. There is a possibility that this frame will be lost due to collision occurring on the communication network. In particular, the lobe medium test MAC in the MAC frame
If the return of the frame to the transmitting terminal is delayed, the processing speed will be correspondingly slow, making it impossible to emulate normal TRN operation.

[0008]

[Means for Solving the Problem] In a communication network control device that interfaces a node device of an amorphous communication network and a terminal of the token ring network standard, a first memory for temporarily storing input frames from the terminal; , a second frame that temporarily stores input frames from the amorphous communication network.
and an input signal identification section for identifying a MAC frame for ring management from among the input frames from the terminal, and when the input signal identification section identifies the MAC frame, the first memory a first loopback path that loops back the lobe medium test MAC frame among the MAC frames to the terminal without passing through the first memory and the second memory; and a second return route for returning to the terminal.

[0009]

[Operation] When a MAC frame transmitted by a terminal of the Token Ring network standard for ring management is input, it is preferentially looped back to the terminal side via the first loopback route, so that it is not transmitted over an undefined communication network. This frame will no longer be lost due to collision. In addition, among these MAC frames, the lobe medium test MAC frame in particular is distinguished from other MAC frames, and is looped back without delay through the second looping path that does not go through the first and second memories, thereby increasing the speed of looping processing. It can be used to simulate the behavior of more conventional Token Ring networks.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained based on the drawings. Figure 2 shows an example of a connection between a TRN terminal and an amorphous communication network,
A plurality of TRN terminals 1 of the TRN standard are a plurality of node devices 2
an amorphous communication network 3 equipped with a communication network control device TAU
(TRN adaptive unit) 4 is connected as an interface.

An example of the configuration of each TAU 4 is shown in FIG. First, a PLL 5 that performs bit synchronization with respect to an input signal from the TRN terminal 1 is provided, and an FIF serving as a first memory temporarily stores an input frame that is an output signal of the PLL 5.
O (first in first out) 6 is provided. The FIFO 6 outputs the data to the amorphous communication network 3. Further, a PLL 7 that performs bit synchronization with the input signal from the amorphous communication network 3 is provided, and a FIFO (first in first out) 8 as a second memory that temporarily stores the input frame that is the output signal. is provided. TRN from this FIFO8
Output to terminal 1. Furthermore, the input signal from the amorphous communication network 3 is inputted to a carrier detection unit 9 for detecting the input of the TRN signal, and furthermore, the output of the PLL 7 is inputted to an address detection unit 10 and an address comparison unit 11 in order. ing. Next, a free token generator 12 is provided on the output side of the FIFO 8, and an output selector 13 selectively outputs the outputs of the FIFO 8 and the free token generator 12 to the TRN terminal 1. Each of these parts is controlled by a sequencer 14.

In this embodiment, an input signal identifying section 15 for identifying a MAC frame from input frames from the TRN terminal 1 is provided on the output side of the PLL 5. The input signal identification unit 15 is used to identify free tokens and frames as well as MAC frames from among frames. When a MAC frame is identified by this input signal identification unit 15, in addition to the normal route to the amorphous communication network 3, the MAC frame is sent via the FIFO 6 as shown by the bold line.
A first return route 16 is formed for returning from the output selector 13 to the TRN terminal 1 side without passing through the IFO 8.

[0013] The input signal identification unit 15 also has a function of particularly identifying a lobe medium test MAC frame among MAC frames, and when this lobe medium test MAC frame is identified, the first Route 1
In addition to 6, the input signal identification unit 15 does not pass through FIFO 6.
A second return path 17 is formed for returning directly from the output selector 13 to the output selector 13.

In such a configuration, the amorphous communication network 3
The input signal is bit-synchronized by the PLL 7 and then temporarily stored in the FIFO 8. In parallel with this,
The address detection unit 10 and address comparison unit 11 compare the address of its own TRN terminal 1 and the destination address of the input frame, and if they match, the input frame is transferred to the FIF
Read from O8, pass through output selector 13 and send to TRN terminal 1
Output to.

On the other hand, the input signal from the TRN terminal 1 is discriminated between a free token and a frame by an input signal discriminator 15, and furthermore, a MAC frame is discriminated, and in the case of a MAC frame, a lobe medium test MAC frame is discriminated. will be done.

Here, as shown in FIG. 3, the MAC frame includes SDEL (8 bytes), AC (8 bytes), and FC (
8 bytes), DA (48 bytes), SA (48 bytes)
, INFO FIELD (m bytes), FCS (32
bytes), EDEL (8 bytes), and FS (8 bytes) frames. Also, INFO F
The IELD frame has a LENGTH (16 bytes) followed by a MAJORVECT ID frame, and a CL
It consists of a frame of ASS (8 bytes) and COMMAND. 08HEX in this COMMAND frame is a lobe media test frame (Lobe Media T
est). Therefore, in a MAC frame, if the 25th byte of the INFO FIELD frame (COMMAND frame) is 08HEX, it is identified as a lobe medium test frame.

As a result of the identification by the input signal identification section 15, if the MAC frame is a MAC frame other than a lobe medium test frame, it is written into the FIFO 6, but the MAC frame is written to be distinguished from other normal frames. Other frames are output to the amorphous communication network 3 side as usual. FIFO6
The MAC frame written in is read out according to the instructions of the sequencer 14, and given priority over the input frame from the amorphous communication network 3, is looped back to the TRN terminal 1 via the output selector 13 via the first loopback path 16, It is not output to the amorphous communication network 3 side. Therefore, the MAC frame is prevented from being lost due to a collision that may occur when it is sent onto the amorphous communication network 3, and the TRN ring management is performed normally.

On the other hand, when a lobe medium test frame is detected by the input signal identifying section 15, it is directly looped back to the TRN terminal 1 via the output selector 13 without passing through the FIFO 6 via the second loopback path 17. In this way, for lobe medium test MAC frames other M
By distinguishing it from an AC frame and returning it without delay via the second return path 17 that does not pass through FIFOs 6 and 8, it is possible to speed up the return process and more accurately emulate the operation of a normal token ring network. can rate.

[0019]

[Effects of the Invention] As described above, the present invention provides a token
An input signal identification unit is provided to identify a MAC frame for ring management from among input frames from a terminal conforming to the ring network standard, and a first loopback path is provided for returning the MAC frame to the terminal with priority when the MAC frame is identified. Since the MAC frame is input from the terminal,
Through this return route, it is preferentially returned to the terminal side, and is sent onto the amorphous communication network to avoid frame loss due to collisions on this amorphous communication network and maintain the management of the free token network. Furthermore, among the MAC frames, the lobe medium test MAC frame is distinguished from other MAC frames, and is looped back to the terminal via a second looping path that does not pass through the first memory and the second memory. Therefore, it is possible to speed up the process of looping back the lobe medium test MAC frame, and it is also possible to more accurately emulate the operation of a normal token ring network.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a basic connection example of a TRN/amorphous communication network.

FIG. 3 is an explanatory diagram showing the format of a MAC frame.

[Explanation of symbols]

1 Token Ring network standard terminal 2 Node device 3 Amorphous communication network 4 Communication network control device 6 First memory 8 Second memory 15 Input signal identification unit 16 First return route 17 Second return route

Claims (1)

[Claims] 1. A communication network control device that interfaces a node device of an amorphous communication network and a terminal of the token ring network standard, comprising: a first memory for temporarily storing an input frame from the terminal; a second memory that temporarily stores input frames from the communication network;
an input signal identification unit that identifies a MAC frame for ring management from among input frames from the terminal; when the input signal identification unit identifies the MAC frame, the MAC frame is transmitted to the a first return route for returning to the terminal without passing through a second memory;
A communication network control device characterized in that a second return path is formed in the MAC frame to return the lobe medium test MAC frame to the terminal without passing through the first memory and the second memory. .