JPS62252238A - Slot accessing system - Google Patents

Abstract

PURPOSE:To improve the efficiency of a transmission line, by transmitting data also to a node shown as the transmission opposite address of a received slot, and to the node shown as the transmission origin address of the received slot, using the received slot. CONSTITUTION:Plural communication control equipments 2-5 are connected on a transmission line, and communication equipments 6-10 are connected to respective communication control equipment. A frame is constituted of two kinds of slot groups, a type(TYPE)1, and a TYPE2. The TYPE1 is a synchronizing information slot for sound, and an image, etc., and the TYPE2 is a data communication slot that is a bit of asynchronous information. A slot consists of the identification flag (F) of the TYPE1 or the TYPE2, a transmission destination address(DA) consisting of seven bits, a token control address(TC) which consists of seven bits, and is a slot control address, and sets (7F)16 as a free token address, a free token flag(TCF), a transmission data(Data), and a frame check code(CRC). When a TYPE1 frame is received, a received DA and its own equipment address(SA) proper to each equipment are compared. When it is DA=SA, the decidion for the TC is performed, and when a transmission is requested, the data is transmitted setting as TCF=1, DA=TC, and TC=SA.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a slot access method, and particularly to a slot access method that can efficiently communicate synchronization information.

[Conventional technology]

The access method in conventional voice and image information networks is described in the paper "Study of high-speed multimedia integrated LAN" by Yoshihama Hamada, Information Network Research Materials, Institute of Electronics and Communication Engineers.
It used a line switching system as described in 1N85-28).

[Problem that the invention seeks to solve]

FIG. 2 shows a conventional example. frame format and
Indicates the timeslot format. A circuit switched area (KE) is used for voice and image communication. Furthermore, the packet information uses empty packets in the exchange area (EX).

In the circuit switching system shown in FIG. 2, m channels (CHl"CHm) for performing circuit switching are connected and voice signals are transmitted.

This is suitable for communication of synchronous information such as image information because there is no variation in transmission delay in principle. However, although the number of channels is large, the channel usage rate is low (for example, on-premises FA
If a circuit switching method is used in cases such as X, videophone, video conference, etc., each channel is fixedly assigned to each time slot, so as the number of channels increases, the transmission path speed increases and the transmission path efficiency decreases. A problem arises.

An object of the present invention is to provide an access method that achieves high transmission path efficiency when the usage rate of a channel for communicating synchronization information is low.

Measures to solve problem C] The method of the present invention is a slot format.

In a slot access method that has a source address indicating a node that transmitted data on a slot and a destination address of the data, the node indicated by the destination address of the received slot is also indicated by the source address of the receiving slot. The present invention is characterized in that it is possible to transmit data using the reception slot to the node that receives the data.

[Effect]

In the circuit switching system, even if the usage rate of channels for communicating synchronization information is low, as the number of channels increases, the number of time slots increases, so it is necessary to increase the transmission speed. This is equivalent to a decrease in transmission path efficiency. This phenomenon is due to the fact that each slot is fixedly assigned to each channel.

One way to increase transmission path efficiency is to use a token passing method. However, the token passing method is generally not suitable for synchronous information communication because the transmission right acquisition waiting time depends on the traffic of other channels and causes communication delay variations. It is desirable to use an access method that combines the features of circuit switching and token passing.

In the present invention, firstly, in order to improve the line efficiency, -channels are not fixedly assigned to each slot, but slots can be commonly used by each channel. To achieve this, we added source and destination address information to each slot. The source address reveals the node using the slot, and the specific address is used to indicate the empty slot status.

When the channel usage rate is low, more channels will share the slot, and the rate of increase in the number of slots will be kept low compared to the rate of increase in the number of channels.

Second, in order to enable synchronous information communication in the first slot format, the channel that once occupied the slot should be controlled to occupy the slot preferentially until the series of communications is completed. , there is no variation in communication delay, and synchronous information communication is possible. At this time, attention is paid to the later slots received by the destination channel. In the case of asynchronous data communication, a response is made using one normal area slot, but in the case of synchronous information communication, a response is not necessary because some data errors can be tolerated. Therefore, if the reception channel is also allowed to transmit data to the source channel using the reception slot, two channels can perform synchronous information communication using one slot, which further improves efficiency. .

[Embodiments of the invention]

A network configuration is shown in FIG. 3. A plurality of communication control devices 2 to 5 are connected to a transmission path 1, and communication devices 116 to 10 are further connected to each communication control device.

Communication device i! 6 and 10 are synchronous information communication devices, and 7 to 10 are synchronous information communication devices.
9 is an asynchronous information communication device.

Hereinafter, one embodiment of the present invention will be described in detail. Figure 1 (a
) shows the frame (Fi) format, and (b) shows the time slot format. A frame consists of two types of slot groups: type (TYPII 1 and TYP [E 2).
E! Reference numeral 1 denotes a slot for communicating synchronous information such as audio, 1 image, etc., and one slot is used during communication between devices 6 and 10 in FIG. TYPE! 2 is a slot for data communication which is asynchronous information, and this slot is used during communication between devices 7 to 9 in FIG. The slot is TYPI! 1 or T
'/Pt! 2 (F) Identification flag (F), a 7-bit transmission destination address (DA), a 7-bit slot control address, and (7F) a token control address (TC) with 16 as a free token address. ), free token flag (TCP),
Transmission data (Data).

and a frame check code (CRC).

However, TYPE! In No. 1, CRC is unnecessary because some bit errors can be tolerated due to the nature of the information.

FIG. 4 shows a flowchart of reception determination processing for TYPR1 frame, FIG. 5 shows a flowchart of reception determination processing for TYPE2 frame, and FIG. 6 shows a flowchart of reception determination processing for TYPR1 frame. 1 and T
A VPR2 common processing unit flowchart is shown. As a result of reception determination processing, there are four types of operation states: reception, transmission, relay, and response determination, but since these are not unique to the present invention, detailed explanations will be omitted.

The reception determination process of T'/PR1 will be explained in detail with reference to FIG. TYPE at 301! When one frame is received, in 302, the received DA and the own device address (SA) unique to each device are compared. If DA=SA, 30
TC is determined in step 3, and when TC≠7F, the following data is regarded as self-addressed information and a reception operation is performed. At this time,
Transmission operations are also performed in parallel.

The presence or absence of a transmission request is also determined in 305, and if there is a transmission request, TCP=1. r) A=TC.

Set TC=SA and transmit data. On the other hand, if there is no transmission request, a response flag is set in 306 (TFC=1
)L, then send. When TC=7F at 303,
This slot]~ is an empty slot, and in 503 of FIG. 6, it is determined whether there is a transmission request, and if the transmission request is served, T
Set CF=O, TC=SA, set DA, and transmit data. On the other hand, if there is no transmission request, the received information is relayed without changing it.

If DA≠SA in 302 of FIG. 4, it is determined in 310 whether or not the own device has the right to use the slot.

If TC≠SA - Does another device have the right to use the slot?
Or it's an empty slot.

This determination is made at 502 in FIG. 6. When TC=7F, this slot is an empty slot, and at 503 it is determined whether or not there is a transmission request, and based on the result, 504, 505.
Or perform the operation 506. If TC≠7F at 502, it is regarded as a slot destined for another source and a relay operation is performed.

- Power cylinder 4 If TC=SA in Figure 310, the own device has the right to occupy the slot. At step 311, it is determined whether there is a transmission request. If there is a transmission request, TCF at 312
=O and send the data. If there is no transmission request, it is determined in 313 whether the communication has ended or not. If not, a relay operation is performed and the exclusive right is maintained, and if it has ended, in 314 Set TC=7F and make the lot an empty slot.

The reception determination process for TYPE 2 will be explained in detail with reference to FIG. When DA==SA in 402, TC is determined in 403. When TC=7F, it is an empty slot and T
Similar to VPRl, the processing after 507 in FIG. 6 is performed. On the other hand, when TC≠7F, the subsequent data is self-addressed data, and a response flag (CTF) is set and transmitted.

If DA≠SA in 402 of FIG. 5, it is determined in 406 whether or not the data is spontaneous data. If TC≠SA, it is data from another source or an empty slot, and TYPE 1.
Similarly, TC=SA performs the processing after 501 in FIG.
In the case of , it is spontaneous information, and a response is determined in 409, TC=7F is set in 407, and this slot is set as an empty slot 1-.

According to this embodiment, by indicating the right to use a slot using a TC, it is possible to improve transmission efficiency in a network with little traffic, similar to the token passing method, and the process of 305:313 in FIG. 4 is a feature. The TYPE 1 method enables synchronous information communication. Furthermore, the same device can use the same slot twice on the ring.
The TYPE 2 method, which does not allow continuous occupancy for more than one cycle, also enables load-balanced data communication.

〔effect〕

According to the present invention, in a communication control device of a network that communicates synchronization information, when the usage rate of a channel is low,
There is no need to secure slots for the number of channels, and data reception channels can also transmit data, so transmission path efficiency can be improved.

[Brief explanation of drawings]

Figure 1 shows the frame format 2 and slot format of two embodiments of the present invention, Figure 2 shows the frame format and time slot format 1-1 in the conventional system, Figure 3 is a schematic diagram of the network configuration, Figure 4 shows T' in the example.
/PE 1 reception determination processing flowchart, FIG. 5 is a reception determination processing flowchart of TYPE 2 in the embodiment, FIG.

Claims (1)

[Claims] 1. In a slot access method in which the slot format includes a source address indicating a node that transmitted data on a slot and a destination address of the data, the node indicated by the destination address of the received slot also A slot access method that allows data to be sent to a node indicated by a source address using the reception slot.