JPH0334647A - Data transmitting system - Google Patents

Abstract

PURPOSE:To relay the frame of control or management data, etc., to be processed preferentially by constituting the subject system so that a communication controller for executing a priority transmission executes a reservation of a slot by using a reservation display part, and executes a data transmission to a reserved and unused slot and an unreserved and unused slot. CONSTITUTION:On a header part of a slot of a high speed trunk LAN 10, a slot reservation display (b) is provided separately from a use display (a). In this state, by a means which transmits data to the high speed trunk LAN 10 in all nodes without being aware of a distinction of the own/other node reservation slots, and also, can execute the transmission by prefetch priority against any slot of a free slot, the transmission is executed in accordance with a utilization state of the high speed trunk LAN 10, and by an equal allocation of the same level as general data without a reservation in the case the use rate is low, and in the case the use rate is high, the reserved transmission is executed preferentially. In such a way, while following the slot prefetch priority (data transmission), the priority control at the time of relaying can be executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a communication control device, and relates to a LAN (Local Area Network).
This invention relates to a data transmission method in a device that connects between

[Conventional technology]

Currently, the communication system is based on the high-speed trunk line L as shown in Figure 2.
Using a plurality of nodes 20 of which AN10 is a connecting device,
For example, there has been a shift to a large-scale network system based on a speed hierarchy that bundles 30 to 80 IEEE802-based low- and medium-speed LANs.

Therefore, the high-speed trunk LAN10 is the low/medium-speed LAN30~
It is necessary to equally allocate the amount of traffic to 80 nodes and relay data between them. For this reason, high-speed trunk LAN
The transmission method in l0 is medium speed LAN30.40
Adopts a fixed data length unit statistical multiplexing method (time slot dynamic allocation method) that increases multiplexing efficiency by dynamically allocating transmission data to empty slots depending on the generation/pause of data transmission requests from .

Note that the interface in the node 20 is a full-duplex communication interface between the high-speed trunk LAN 10 and a medium-speed LA
The communication interface between N30 and 40 is a half-duplex communication interface, and the medium/low speed LANs 30 to 80 use variable data length frame units, and the high speed trunk LAN l0 has a fixed data length that divides the above frame data into multiple pieces of constant data length. It is a unit.

Conventionally, in the node 20 in this type of configuration, as shown in FIG.
Data transfer path 21 to l0 and further high-speed trunk LAN l
A two-system data bus structure is adopted, that is, a data transfer path 22 from 0 to medium-speed LAN 30.40, and is matched to the full-duplex communication interface performed by trunk LAN interface 23 as a data transfer system and the transmission speed of high-speed trunk LAN 10.

Therefore, the hardware architecture in the node 20 includes DMA controllers 25 and 27 that transfer data via transfer paths 21 and 22, and these DM
A processor 26.controlling the A controller 25.27.
28 is used to transfer relay data in parallel to main line LA.
This corresponds to full-duplex communication performed by the N interface 23. Further, for the medium-speed LAN 30.40 of half-duplex communication, an interface is provided in which the medium-speed LAN interface 24 combines the transfer paths 21.22 into one system.

Here, the operation (data transmission/reception method) in the trunk LAN 10 using the conventional statistical multiplexing method described above will be explained using FIG. The trunk LAN 10 is divided and operated in units of fixed-length slots as shown in Figure 4, and each has a header section that indicates whether or not the slot is in use and the destination, and an information area that contains actual data. It is divided into When each node transmits data, it checks from the header whether the slot in question is in use or not, puts the transmission data in the information area of the unused slot, and displays the header as being in use. On the other hand, for data reception, it is confirmed that the relevant slot is valid by the in-use indication in the header, and if the destination is the own node, the main
At the same time as importing data, change the display from in use to unused.

The above processing is performed by the trunk LAN interface 23 shown in FIG.
It is controlled as follows.

In FIG. 5, RX is a reception determination unit that determines whether the slot in question is addressed to its own node from the header part, and R8EL selects either route Ra or Rh based on the control signal RCTL instruction from reception determination unit RX. RC is a release instruction unit that changes the header section from in use to unused indication to release the slot in accordance with the control signal RCTL from the reception determination unit RX, and TX is a release instruction unit that releases the slot in question, and TX is a transmission request TREQ from the transmission control processor 26. TSEL is a selector that selects either route T a or T b in response to a control signal TCTL from the transmission determination unit TX, and TC is a transmission determination unit TX. This is an acquisition instruction unit that acquires a header in response to a control signal TCTL from the header.

When the reception determination unit RX detects data (slot) addressed to its own node from the trunk LAN l0, the reception determination unit RX outputs the reception data to the transfer path 22 and also outputs the control signal RCTL.
Displays unused header to release instruction section RC and selector R
Give a route Rb selection instruction to 5EL. Main line L here
If the reception slot from AN10 is addressed to another node or is an unused slot, the reception determination unit RX outputs data to the route Ra, and also outputs the data to the route Ra using the control signal RCTL.
The selection is instructed to the selector R8EL, and the reception slot (data) is passed through to the transmission determination unit TX.

On the other hand, the transmission determination unit TX that received the transmission request selects the selector R.
The header of the slot from the trunk LANl0 sent from SEL is monitored, and if the slot is unused, the selector TSE selects the route Tb using the control signal TCTL.
It also instructs the acquisition instruction unit TC to generate a header indicating that the slot is in use. Here is the main LAN
If the reception slot from 0 is in use or there is no transmission request TREQ, the transmission determination unit TX determines the route 1-T.
It outputs data to slot a, and instructs selector TSE L to select route 1'' Ta using control signal T CT L to cause trunk LAN l0 to pass through the i slot (data).

Incidentally, as a related device of this type, for example, Japanese Patent Publication No. 1988-97037 "Loop Network System" can be mentioned.

[Problem to be solved by the invention]

As described above, conventionally, a statistical multiplexing method has been adopted in order to equally allocate access (transmission) opportunities to all the nodes 20 to the high-speed trunk LAN 10.

On the other hand, the frames relayed to the entire network via the high-speed trunk 1 LAN] ○ include, in addition to general data, management data for managing the network, control data for emergency control, and frames with various priority levels. Data exists.

Considering that the high-speed trunk LAN l0 is occupied by a large amount of general data such as file data, the statistical multiplexing method is basically a preemption priority method for empty slots, so it should be processed with priority. Frames such as control or management data cannot be relayed.

An object of the present invention is to provide a data transmission method that solves the above problems.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a slot with at least a slot use display section and a reservation display section, and a communication control device that performs priority transmission uses the reservation display section to reserve slots, and reserve unused slots and unused slots. The configuration is such that data is transmitted to reserved and unused slots. That is, (1) a slot reservation display is provided in the header section of each slot of the high-speed backbone LAN 10 in addition to the slot usage display.

(2) Data transmission to the high-speed backbone LAN 10 in all nodes is made possible without being aware of the distinction between self/other node slot reservations, and with priority given to any empty slot.

■To simplify the process, the reservation display does not distinguish between reservation nodes.

(2) Slot reservation at the time of data transmission is for a slot whose header indicates that it is in use and no reservation is made, and reservation cancellation is made when transmitting data to an empty slot I- that is received after reservation and has a slot reservation indication.

(2) However, in consideration of the use of slots reserved by other nodes, the reservation is not canceled when transmitting data to an empty slot (reserved by other nodes) with a slot usage indication detected before slot reservation.

■Nodes that do not reserve transmission will transmit only in empty slots with no reservation indication.

(2) After slot reservation, if an empty slot 1- that can be transmitted is detected, data is transmitted to the empty slot, and the reservation display of the reservation slot detected thereafter is unconditionally canceled.

■ Add and hold the number of reservations to slots that are currently in use and have no reservations as Unconditionally cancel slot reservation display.

(2) If the next transmission request occurs when X-Z=n (n#o), the management in (2) above is continuously controlled.

[Effect]

With the means described above, the present invention enables priority control during relaying while following the slot preemption priority (data transmission) of the statistical multiplexing method.

In other words, a slot reservation indication is provided in the header of the slot of the high-speed backbone LAN 10 in addition to a usage indication, so that all nodes can send data to the high-speed backbone LAN 10 without being aware of the distinction between own/other node reserved slots, and can also send data to any empty slot. According to the usage status of the high-speed trunk LAN 10,
■When the usage rate is low, transmission is performed without reservation and with the same level of equal allocation as general data; ■When the usage rate is high, reservation transmission is performed with priority.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 6. FIG. 1 shows the LA of the present invention in the high-speed trunk LAN10.
This is an example of N operation, in which a fixed length slot is divided into an information area and a header as in the conventional case, and this header section is further divided into a slot usage indication a and a slot reservation indication.

In FIG. 6, RSV is a reservation determination unit that monitors the slot header in response to a reservation request RSVMD from the transmission control processor 26 in FIG. 3, and R3VC is a reservation determination unit RSV.
This is a reservation specifying section that displays the reservation of the slot in accordance with the control signal R8VCTL from the control signal R8VCTL, and the other basic configuration is the same as that in FIG. Here, a="l" indicates that the slot is in use, = JJ Q 11 indicates that the slot is not in use, b = Kl I II indicates that the slot is in use, and b = "O" represents that the slot is not reserved.

Each node 20 sends normal data (reservation request R3VMD
(none), monitors the slot header flowing on the main LAN 10, puts the transmission data on the unused slot, and uses the acquisition instruction unit TC to change the usage indication of the header from the unused indication (a=O). Change to medium display (mini 1) and send data. On the other hand, data such as network management or control frames that should be transmitted preferentially is transmitted using the reservation determining section RSV and the reservation specifying section R8VC to perform reservation control according to the display pattern of the slot header as described below.

Here, the reservation designation unit R8VC is a circuit that makes a reservation for the slot in accordance with an instruction from the reservation determination unit RSV. Specifically, the reservation designation part R8VC.

A control signal R which is a reservation control signal from the reservation determination unit RSV
8According to the instructions of VCTL, the high-speed main line LA shown in Figure 1
Detects the slot reservation display timing belonging to the header section of the slot flowing on Nl0 and changes its contents (reservation instruction is b = “O” → # (l II, reservation cancellation is b = “l” → “ 0”).In addition, the reservation specification section R3VC
Detection of change timing of slot reservation display in
As mentioned above, it can also be substituted at the output timing of the control signal R8VCTL that Sv gives to the reservation designation section R8VC.

1) a=b=0 In this case, even if the slot is neither used nor reserved, and there is a reservation request RSVMD to the reservation determination unit RSV, normal data transmission will occur. That is, the reservation determination unit RSV does not instruct the reservation designation unit R3VC to designate a reservation for the slot header (control signal R3VC:TL). Therefore, the transmission determination unit TX determines that the slot in question is an empty slot (a
=b=o) and gives an instruction to the acquisition instruction unit TC to indicate that the slot is in use (mini 1) and an instruction to select the route Tb to the selector TSEL using the control signal TCTL.

2) a=1. b=0 In this case, the slot in question is in use without reservation, and the reservation determination unit RSV uses the trunk LAN10 of the slot in question.
- In order to secure the usage right after the cycle, the control signal TCTL issues a reservation instruction (b=1) to the reservation designation unit R8VC, and waits for either case 3) shown below or 1) described above. Here, if the slot following the case 2) is the case l) (a=b=o) described above, the reserved slot is the main line L in order to transmit data to the non-reserved slot 1-. Go around AN10. Therefore, in the case of 2) → 1) above, reserved slot (b) after data transmission
= 1), the reservation determination unit R8V unconditionally transmits the control signal T, regardless of whether the slot is used or not.
CTL issues a reservation cancellation instruction (b=o) to the reservation designation unit RSVC.

3) a=o, b=1 In this case, the reserved slot returns as an empty slot after going around the main LAN 10.

Therefore, the transmission determination unit TX outputs the transmission data to the slot and indicates that the slot is in use (mini 1), and the reservation determination unit R8V releases the reservation to the reservation specification unit RSVC (b=o) using the control signal RSVCTL. instruct.

In this case, the slot 1- is in use and reserved. Therefore, in the case of one book, the reservation judgment unit R3
V and transmission determination unit TX do not operate (control signal TCTL
and RSVCTL acquisition fingernails and no reservation instructions),
The slot passes through the trunk LAN interface 23.

As described above, according to the present invention, even when there are no empty slots in the trunk LAN 10, high-priority control frames and the like can be transmitted preferentially by acquiring slot reservations.

On the other hand, by setting the configuration of the reservation determination unit R8V to the configuration shown in FIG. 7, more effective priority data transmission can be realized.

In FIG. 7, the HDT detects the usage/reservation status of the slot y1 using the usage (a) and reservation (b) display information of the slot 1 in the received slot header from the selector RSE L. section, TA is header detection section H
DT is a transmittable signal indicating that the slot is a transmittable slot, and REG is a register that stores the number of reserved slots necessary for data transmission and has the function of subtracting the stored reserved slot number from the transmittable slot. , TOP is the contents of register REG (number of reservations RN)
becomes It O11, indicating that the reserved data transmission has ended. Reserve empty slot transmission signal indicating transmission.

ADD is an addition unit that calculates (X-Z) using the transmission reservation instruction X and reserved empty slot transmission signal Z, and obtains the difference between the total number of reservations for slots on the trunk LAN 10 and the total number of data transmissions to the reserved slots.

N is a reservation cancellation signal that instructs to cancel reservations for reservation slots corresponding to the number of differences when the adder ADD has a difference (X-Z)≠0 at the time when the transmission end signal TOP is generated, and OR is the seventh reservation cancellation signal.
In the figure, it is an OR circuit that outputs a transmission reservation instruction signal X and a reservation cancellation signal 4N as a control signal RSVCTL.

The transmission control processor 26 sends a reservation request RS V MD and a reservation number RN (register RE G
) is given, the header detector I-(D T is a non-reservable busy slot (a=1.
A reservation instruction signal X for b=o) is issued until the contents of the register REG become #Qu (end of transmission) to reserve a slot, and further an addition instruction is issued to the adder ADD. During this time, the header detection unit HDT detects reserved empty slots (a=o, b=1) which are transmittable slots I- other than the above-mentioned unreserved used slots (a=1.b=o) and unreserved empty slots. When (a=b=o) is detected, the reservation instruction signal =1), a reserved empty slot transmission signal 2 is issued to the adder ADD to issue a subtraction instruction.

Here, when the contents of the register REG become ii O'' and the transmission is completed, the adder ADD is activated by the transmission end signal yrop.
In response to this, if the addition result is (X-Z≠0), the addition unit ADD reserves the reservation cancellation signal N until (x-z=o). An instruction is given to the slot (b=1) to cancel the reservation of the slot (b=O). Please note that reserved slot 1 after sending is completed.
- If the next transmission request occurs while the reservation is being canceled, the register REG sends a transmission end signal TO that prompts the reservation to be canceled.
The output of P is stopped, the contents of the adder ADD are held, and the series of reservation processing described above is continued. That is, in this embodiment, advance reservations for transmission slots are made, and after the transmission is completed, unnecessary advance reservation slots remaining on the trunk LAN 10 are canceled, and during this time, the remaining number of cancellations is maintained and continued for the next transmission request. Performs reserved transmission processing.

〔Effect of the invention〕

According to the present invention, priority data transmission based on advance reservation can be performed in accordance with the usage status of the trunk LAN 10, while following the slot preemption priority (data transmission) of the statistical multiplexing method.

In other words, even in the case of reserved transmission, when the usage rate is low, reserved transmission is given priority when the usage rate is low, as is the case with general data where no reserved transmission is performed for empty slots without reservations. However, it can be sent in the same way as general data sent to empty slots without reservations.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the present invention, FIG. 2 is a network configuration diagram, FIG. 3 is an explanatory diagram of nodes, and FIG. 4. FIG. 5 is an explanatory diagram of a conventional example, FIG. 6 is a diagram of an embodiment of the present invention,
FIG. 7 is a diagram showing another embodiment of the present invention. Explanation of symbols 10...High speed trunk LAN, 20...Node, 21°22...Transfer route, 30-80...Medium/low speed LAN,
23... Main line LAN interface, R8V... Reservation determination unit, R8VCTL... Control signal, R5VC...
・Reservation specification section, R8VMD...reservation request signal, TRE
Q...Transmission request, RX...Reception determination unit, RC...
Open instruction section, RCTL...control signal, R3EL...
Selector, Ra, Rh...Reception 1 slot I-passing route, TX...Transmission determination section, TC...Acquisition instruction section, 'I
'CTL...control signal, TSEL...selector, T
a, Tb... Slot passage route, RN... Number of reserved transmissions, HDT... Header detection section, ADD... Addition section, REG... Register section, OR... OR circuit,
...Reservation instruction signal, Z...Reservation empty slot transmission signal,
N...Reservation cancellation signal, TA...Transmittable signal, TO
P: Transmission end signal. Shimazu Collection 2 Figure Menu Speed Trunk Line LAN 0 Shuli Zuwei Zu Collection Man

Claims (1)

[Claims] 1. In a transmission path operated by a statistical multiplexing method (time slot dynamic allocation method) in units of fixed data length and a communication control device that sends and receives communication data to and from the transmission path, the slot is The communication control device, which is provided with at least a usage display section and a reservation display section for the slot and performs priority transmission, uses the reservation display section to reserve the slot, and transmits data to the reserved and unused slots and the unreserved and unused slots. A data transmission method characterized by performing the following. 2. The data transmission method according to claim 1, wherein the communication control device that does not perform priority transmission transmits data to an unreserved and unused slot. 3. The data transmission method according to claim 1, wherein when data is transmitted to an unreserved and unused slot after slot reservation, the reservation display for the next reserved slot is canceled. 4. In the data transmission method according to claim 1, at the time of reserved transmission, the number of reserved transmissions is reserved in advance for unreserved and used slots, and the unreserved and unused slots and reserved and unused slots detected during the reservation period are At the same time, the difference between the number of reserved slots for unreserved slots and the number of data transmission for reserved and unused slots is calculated, and if the difference is not zero at the time of final data transmission,
A data transmission method characterized by canceling a reservation display of a reservation slot corresponding to the number of differences. 5. In the data transmission method according to claim 4, when the next reservation data transmission is performed before the process of canceling the reservation display of the reservation slot corresponding to the number of differences is completed, the difference up to the present time is held; A data transmission method characterized by continuing to calculate the difference between the number of reserved slots for the unreserved slot and the number of data transmissions for the reserved unused slot for the next number of reserved transmissions.