JPH03201742A - Token ring type lan - Google Patents

Abstract

PURPOSE:To improve the real time response by controlling the LAN depending on the priority of the present station data, ring priority, reservation priority and priority of a recovered frame. CONSTITUTION:When a communication station receives a token circulated through a transmission line and the priority of a data of the present station is discriminated to be higher priority, the token is not sent and a frame being a transmission data of the present station is sent. When the frame sent through the transmission line is received and the priority of the data of the present station is discriminated to be higher, the priority of the data of the present station is written in a reservation priority storage area of the frame. Moreover, when the priority of the frame is discriminated to be higher in the midst of the transmission of the frame being the transmission data of the present station, the transmission of the frame being the transmission data of its own station is stopped to generate a token having the reservation priority of the frame. Thus, the real time response is improved.

Description

Detailed Description of the Invention: "Industrial Application Field - 1 The present invention is a token ring type LAN (LAN) that connects a plurality of communication stations in a ring shape through a transmission path and transfers data between these stations. net).

"Conventional technology" Conventional LAN communication method that can handle real-time information 1
There are methods shown below.

(1) Time stamp method Each communication station adds the time of data occurrence to the data (time stamp) and transfers the data.

(2) Circuit-switched method Circuit-switched LA using methods such as band division or time division
One line is allocated between each communication station using N. At least one line is used for controlling line allocation and the like using a packet-switched protocol.

(3) Token passing method This is a method in which each communication station obtains a transmission right by acquiring tokens circulating on a transmission path, and has the following characteristics.

(b) By controlling transmitting stations using tokens, competitive transmission conditions (collisions) between multiple stations are avoided.

(b) Equal opportunities for each communication station will be achieved by limiting the holding period of tokens and sequentially transferring tokens to the next station.

(c) By assigning priorities to tokens, high priority data can be passed preferentially.

(4) Hybrid method This method uses two different protocols.

One method is to use physically double rings and change the real-time response of each, and the other is to prepare one ring with two protocols, one for real-time use and one for non-real-time use, and use either one as appropriate. There is a method using a protocol.

``Problems to be Solved by the Invention'' By the way, the conventional LAN described above was constructed for fields that do not require relatively real-time responsiveness, such as file exchange or communication of keystrokes from terminals.

However, in the field of music, such as electronic musical instruments, real-time responsiveness is required to improve the expressiveness of performances. Furthermore, in the case of automatic performance, the sequencer station can receive large-scale sequence information to be played from the file server station while sending performance information to the musical instrument station;
That is, real-time responsiveness and large-scale data communication must coexist.

These requirements are not limited to the field of music, but are considered to be basic requirements for future LANs.

However, conventional LANs have the drawback of not being able to fully meet the above requirements.

For example, the time stamp method (1) is intended to solve the problem of recording a performance.

Further, although the line switching type system (2) can directly solve the above-mentioned requirements, it has the disadvantage that it is difficult to decide in advance how many lines should be prepared. I mean,
This is because ideally, the effect of an increase in the number of stations would be small, and the performance would decrease continuously according to the amount of data.

Furthermore, the packet-switched LAN based on the token passing method (3) performs collision avoidance, equal opportunity, and priority processing among multiple stations, and is excellent in real-time responsiveness. In particular, in the case of the token ring type, the influence of an increase in the number of stations is small, and the performance continuously decreases depending on the amount of data.

In this case, real-time responsiveness depends on the token holding time of each communication station. However, shortening this time has the disadvantage that communication efficiency decreases when transferring large-scale data.

In addition, in the hybrid method (4), first, the method using dual physical token rings has the disadvantage that the equipment is complicated and expensive. Also, it uses two protocols. This method has the disadvantage that control is complicated and maintenance is difficult.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a data transfer method in a token ring type LAN that can easily improve real-time responsiveness without reducing the communication efficiency of large-scale data. The purpose is

"Means for Solving the Problem" The invention described in claim 1 provides a method for obtaining a plurality of stations, a transmission line connecting the plurality of stations, and a data transmission cage circulating in the transmission line. In a token ring LAN that has tokens and frames that hold and transport data,
The token has a ring priority storage area for storing the priority for data transmission, the frame has a reserved priority storage area for storing the data priority of each station, and the frame has a ring priority storage area for storing the priority for data transmission. When a token circulating on the transmission path is received, the priority of the data of the local station is compared with the ring priority, and the priority of the data of the local station is determined to be higher. In some cases, a frame generating means that does not transmit the token and transmits a frame that is data transmitted by the own station, and when receiving a frame transmitted through the transmission path, the priority of the data of the own station and the reservation priority. data transmission reservation means for writing the priority of the data of the own station into a reservation priority storage area of the frame when the priority of the data of the own station is determined to be higher than the priority of the data of the own station; While transmitting a frame that is the transmission data of the own station, the reservation priority of the collected frame is compared with the priority of the data of the own station, and the reservation priority of the frame is determined. The present invention is characterized in that it has a token generating means that stops sending the frame which is the transmission data of the own station when it is determined that the priority is high, and generates a token having the reservation priority of the frame.

Further, the invention described in claim 2 provides a plurality of stations, a transmission line for communicating between the plurality of stations, a token for obtaining a transmission mode of data circulating in the transmission line, and a predetermined method for transmitting data. A token ring LAN having a frame divided into lengths and holding and transporting the divided data, the token having a ring priority storage area for storing priority for data transmission, The frame has a reserved priority storage area for storing the priority of data of each station, and the box stores the data priority of the own station and the frame generating means that compares the ring priority with the data of the own station and, when determining that the priority of the data of the own station is higher, does not transmit the token and transmits a frame that is the data sent from the own station; , when transmitting the data of the own station, if the size of the data of the own station is larger than a predetermined value, the size of the data is divided into pieces smaller than the predetermined value and stored in the data storage area of the frame. data dividing means for storing and transmitting the frame, and when receiving the frame transmitted through the transmission path, compares the priority of the data of the own station with the reservation priority, and determines the priority of the data of the own station. data transmission reservation means for writing the priority of the own station's data in the reserved priority storage area of the frame, and transmitting the frame that is the transmission data of the own station when it is determined that the priority is higher than the frame. While I was
The reservation priority of the collected frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, it is the transmission data of the own station. The present invention is characterized by comprising a token generating means for stopping transmission of the frame and generating a token having the reservation priority of the frame.

Furthermore, the invention described in claim 3 provides a plurality of stations, a transmission path that communicates between the plurality of stations, a token for obtaining the right to transmit data that circulates in the transmission path, and a predetermined transmission path for transmitting data. A token ring LAN having a frame that is divided into lengths and holds and conveys the divided data,
The token has a ring priority storage area for storing the priority for data transmission, the frame has a reserved priority storage area for storing the data priority of each station, and the frame has a ring priority storage area for storing the priority for data transmission. When a token circulating on the transmission path is received, the priority of the data of the local station is compared with the ring priority, and the priority of the data of the local station is determined to be higher. In some cases, the frame generation means does not transmit the token and transmits a frame that is the transmission data of the own station, and when the priority of the data of the own station is lower than a predetermined value when transmitting the data of the own station comprises a data dividing means for dividing the data size into a size smaller than a predetermined value, storing the data in a data storage area of the frame, and transmitting the frame; and upon receiving the frame transmitted through the transmission path. , compares the priority of the data of the own station with the reservation priority, and if it is determined that the priority of the data of the own station is higher, the data of the own station is stored in the reservation priority storage area of the frame. a data transmission reservation means for writing the priority of the data transmitted by the local station; When the comparison is made and it is determined that the reservation priority of the frame has a higher priority, the transmission of the frame that is the transmission data of the own station is stopped, and a token having the reservation priority of the frame is generated. The present invention is characterized in that it has a token generation means.

In addition, the invention described in claim 4 provides a plurality of stations, a transmission path that communicates between the plurality of stations, a token for obtaining the right to transmit data that circulates in the transmission path, and a transmission path for transmitting data in a predetermined manner. A token ring LAN having a frame that is divided into lengths and holds and transports the divided data,
The token has a ring priority storage area for storing the priority for data transmission, the frame has a reserved priority storage area for storing the data priority of each station, and the frame has a ring priority storage area for storing the priority for data transmission. When a token circulating on the transmission path is received, the priority of the data of the local station is compared with the ring priority, and the priority of the data of the local station is determined to be higher. In some cases, the frame generation means does not transmit the token and transmits a frame that is the transmission data of the own station, and when the size of the data of the own station is larger than a predetermined value when transmitting the data of the own station. comprises a data dividing means for dividing the data size into a size smaller than a predetermined value, storing the data in a data storage area of the frame, and transmitting the frame; and upon receiving the frame to be transmitted through the transmission path. , compares the priority of the data of the own station with the reservation priority, and if it is determined that the priority of the data of the own station is higher, the data of the own station is stored in the reservation priority storage area of the frame. a data transmission reservation means for writing the priority of the transmission data;
The reservation priority of the collected frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, it is the transmission data of the own station. Token generation means for interrupting frame transmission, storing and storing the reservation priority of the frame in its own station, and generating a token having the priority;
When receiving a token circulating on the transmission path, compares the stored priority of the own station with the ring priority;
a priority operating means that restores the priority of the token operated by the local station to the original priority and restarts the interrupted transmission of the frame, which is the transmission data of the local station, on the condition that these priorities match; It is characterized by having

In addition, the invention described in claim 5 provides a plurality of stations, a transmission path that connects the plurality of stations, a token for obtaining the right to transmit data that circulates in the transmission path, and a predetermined transmission line for transmitting data. A token ring LAN having a frame divided into lengths and holding and transporting the divided data, the token having a ring priority storage area for storing priority for data transmission, The frame has a reserved priority storage area for storing the priority of data of each station, and the box stores the data priority of the own station and the frame generating means that compares the ring priority with the data of the own station and, when determining that the priority of the data of the own station is higher, does not transmit the token and transmits a frame that is the data sent from the own station; , iia When transmitting the data of the own station, if the priority of the data of the own station is lower than a predetermined value, the size of the data is divided into pieces smaller than the predetermined value and the data storage area of the frame is and a data division means for storing the frame in the transmission path and transmitting the frame, and when receiving the frame transmitted through the transmission path, compares the priority of the data of the own station with the reservation priority, and divides the data of the own station. data transmission reservation means for writing the priority of data of the local station into a reservation priority storage area of the frame when the priority is determined to be higher; While doing this,
The reservation priority of the collected frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, it is the transmission data of the own station. Token generation means for interrupting frame transmission, storing and storing the reservation priority of the frame in its own station, and generating a token having the priority;
When receiving a token circulating on the transmission path, compares the stored priority of the own station with the ring priority;
a priority operating means that restores the priority of the token operated by the local station to the original priority and restarts the interrupted transmission of the frame, which is the transmission data of the local station, on the condition that these priorities match; It is characterized by having

"Operation" According to the invention described in claim 1, when a communication station receives a token circulating on a transmission path, it compares the priority of its own data with the ring priority, and determines the priority of its own data. When it is determined that the priority is higher, the token is not transmitted, and the frame that is the transmission data of the own station is transmitted.

Also, when receiving a frame transmitted through the transmission path, the data priority of the own station is compared with the reservation priority, and if it is determined that the priority of the data of the own station is higher,
The priority of data of the own station is written in the reservation priority storage area of that frame.

Furthermore, while transmitting a frame that is data transmitted by the own station, the reservation priority of the collected frame is compared with the priority of the data of the own station, and the reservation priority of the frame is determined to have a higher priority. When it is determined that the frame is high, the transmission of the frame, which is the transmission data of the own station, is stopped, and a token having the reservation priority of the frame is generated.

Further, according to the invention described in claim 2, when the communication station receives the token circulating on the transmission path, the communication station compares the priority of the data of the own station with the ring priority, and gives priority to the data of the own station. When it is determined that the token has a higher priority, the station does not transmit that token and transmits a frame that is its own transmission data.

In addition, when transmitting data from the own station, if the size of the data from the own station is larger than a predetermined value, the data size is divided into pieces smaller than the predetermined value and stored in the data storage area of the frame. and sends out the frame.

Furthermore, when receiving a frame transmitted through a transmission path,
Compare the priority of your own station's data with the reservation priority, and if it is determined that the priority of your own data is higher, the priority of your own data is stored in the reservation priority storage area of the frame. Write.

In addition, while transmitting a frame that is the transmission data of the own station, the reservation priority of the collected frame is compared with the priority of the data of the own station, and the reservation priority of the frame is determined to be higher. When it is determined that the frame is high, the transmission of the frame that is the transmission data of the local station is stopped, and a token having the reservation priority of that frame is generated.

Furthermore, according to the invention described in claim 3, the communication station:
When it receives a token circulating on the transmission path, it compares the priority of its own data with the ring priority, and if it determines that the priority of its own data is higher, it transmits the token. The station cannot send a frame, which is its own sending data.

In addition, when transmitting data from the own station, if the priority of the data from the own station is lower than a predetermined value, the size of the data is divided into pieces smaller than the predetermined value and stored in the data storage area of the frame. and transmits that frame.

Furthermore, when receiving a frame transmitted through a transmission path,
Compare the priority of your own station's data with the reservation priority, and if it is determined that the priority of your own data is higher, the priority of your own data is stored in the reservation priority storage area of that frame. Write the degree.

In addition, while transmitting a frame that is the transmission data of the own station, the reservation priority of the collected frame is compared with the priority of the data of the own station, and the reservation priority of the frame is determined to be higher. When it is determined that the frame is high, the transmission of the frame, which is the transmission data of the own station, is stopped, and a token having the reservation priority of the frame is generated.

In addition, according to the invention set forth in claim 4, the communication station:
When it receives a token circulating on the transmission path, it compares the priority of its own data with the ring priority, and if it determines that the priority of its own data is higher, it transmits the token. The station cannot send a frame, which is its own sending data.

In addition, when transmitting data from the own station, if the size of the data from the own station is larger than a predetermined value, the data size is divided into pieces smaller than the predetermined value and stored in the data storage area of the frame. and transmits that frame.

Furthermore, when receiving a frame transmitted through a transmission path,
Compare the priority of your own station's data with the reservation priority, and if it is determined that the priority of your own data is higher, the priority of your own data is stored in the reservation priority storage area of that frame. Write the degree.

In addition, while sending Frenim, which is the sending data of the own station, the reservation priority of the collected frame is compared with the priority of the data of the own station, and the reservation priority of the frame is determined to be higher. When it is determined that the frame is high, it interrupts the transmission of the frame that is the transmission data of its own station, stores the reservation priority of that frame in its own station, and generates a token having that priority.

Also, when receiving a token circulating on the transmission path, the priority stored in the own station is compared with the ring priority, and if these priorities match, the token operated by the own station is given priority. The transmission rate is returned to the original state and the transmission of frames, which is the transmission data of the own station, is resumed.

Further, according to the invention described in claim 5, when the communication station receives the token circulating on the transmission path, the communication station compares the priority of the data of the own station with the ring priority, and gives priority to the data of the own station. When it is determined that the token has a higher priority, the station does not transmit that token and transmits a frame that is its own transmission data.

In addition, when transmitting data from the own station, if the priority of the data from the own station is lower than a predetermined value, the size of the data is divided into pieces smaller than the predetermined value and stored in the data storage area of the frame. and transmits that frame.

Furthermore, when receiving a frame transmitted through a transmission path,
Compare the priority of your own station's data with the reservation priority, and if it is determined that the priority of your own data is higher, the priority of your own data is stored in the reservation priority storage area of that frame. Write the degree.

In addition, while transmitting a frame that is the transmission data of the own station, the reservation priority of the collected frame is compared with the priority of the data of the own station, and the reservation priority of the frame is determined to be higher. When it is determined that the frame is high, the transmission of the frame, which is the transmission data of the local station, is interrupted, the reservation priority of the frame is saved and stored in the local station, and a token having that priority is generated.

Also, when receiving a token circulating on the transmission path, the priority stored in the own station is compared with the ring priority, and if these priorities match, the token operated by the own station is given priority. The transmission rate is returned to the original state and the transmission of frames, which is the transmission data of the own station, is resumed.

"Embodiment" Before describing an embodiment of the present invention, a basic idea for solving the above-mentioned problems will be explained.

First, among the above-mentioned LAN communication methods,
Adopts token ring method. However, in this system, real-time responsiveness depends on the communication station's token holding time, as described above. In order to shorten the token holding time, each frame needs to be made as small as possible before being transferred.

However, considering communication efficiency when transferring large-scale data, it is necessary to transfer as much data as possible with one token acquisition.

Note that normally, data with low priority is long and data with high priority is short.

Therefore, in the present invention, the concept of divided transfer, in which long data is divided into short frames and transferred instead of being made into long frames, and the concept of multi-frame transfer, in which multiple frames are continuously transferred with one token acquisition, The concept of interrupt transfer is introduced, in which a frame that needs to be transferred in real time is interrupted and transferred during multi-frame transfer or divided transfer.

First, transmission data is sorted into low priority data and high priority data. Next, the transmitting station divides the low-priority data into short frames and transmits them in multiple frames, and the receiving station assembles data from the frames. Then, other communication stations insert a high-priority frame between the frames that are being divided and transferred and transfer them. This does not affect interrupted parties or split transfers.

By adopting the concept explained above, real-time responsiveness can be easily improved without reducing the communication efficiency of large-scale data.

Next, the concept of boundary priority for sorting transmission data into low-priority data and high-priority data will be explained. First, when there are many types of long data, that is, when there are multiple priorities of data that must be divided and transferred, the highest priority among those priorities is set as the boundary priority.

Then, by changing the priority of a frame to be divided and transferred by a communication station to a boundary priority and forwarding that frame, division and transfer of a frame with a higher priority than that frame's priority is prevented, that is, Conflicts between divided transfers can be prevented, and data processing becomes easier.

Furthermore, if a high priority reservation is made during a divided transfer and the communication station interrupts the divided transfer, in order to resume the divided transfer, it is necessary to make a reservation assuming that the own station has data with boundary priority. . This is because if the priority of the original data is lower than the boundary priority, if there is data in the pond communication station that has a higher priority than that priority and a priority that can be divided and transferred, This is because the communication station acquires the token and starts divided transfer. Furthermore, if the communication station that interrupted the divided transfer acquires a boundary-priority token, instead of temporarily releasing the boundary-priority token as in the past, it will continue to divide and transfer the remaining frames. Need to restart.

In addition, if you make the boundary priority a fictitious priority or prevent data with boundary priority from being transferred with boundary priority, if you acquire a boundary priority token as in the past, - The boundary priority token may be released once.

In this case, data with boundary priority is transferred with its priority raised or lowered by one level than its actual priority.

Next, the respective formats of the token and frame used in the present invention are shown below.

(a) Token format SD ACHD Here, SD is a starting delimiter (1 octet) that indicates the start of the token, and AC has information about the sender and information for transmission reservation, and is used to distinguish between tokens and frames. ED is an ending delimiter (1 octet) indicating the end of the token.

(b) Frame format SD ACPCDA SA INFOFC8ED FS
Here, SD is a starting delimiter (1 octet) indicating the start of a frame, and AC has information such as frame priority and reception of reservations from other communication stations, as well as information for distinguishing between tokens and frames. FC is a frame control (1 octet) that also has information on frame type and divisional transfer.

In addition, DA and SA are the destination address and source address (2 octets), which have information on the destination and source address of the data, respectively, and INFO is the data part to be transmitted, and one frame contains 0 to 136 octets. This is information that can transfer octets of data. The reason for limiting the maximum frame length to 136 octets of the INFO field is to guarantee real-time responsiveness.

Additionally, the FCS is a frame test sequence (2 octets). This is information for testing whether information has been dropped or changed during frame transfer.
The FO part is the object of inspection.

In addition, ED is an ending delimiter (1 octet) indicating the end of the frame, and PS is a frame status (1 octet) that holds information such as whether the frame has been read or not and is used for determining abnormalities.

Next, of the token and frame formats described above, access control (AC) and frame control (FC), which are particularly relevant to the present invention, will be explained in more detail.

(a) Access control (AC) Pi Pt P+ T M R11Rt
Rt(i)P i (i = 1 to 3) is a priority index bit indicating the priority of a token or frame on the LAN ring (hereinafter referred to as ring priority Pr).

Here, a specific example of the ring priority P is shown.

Ps Pg Pt 0 0 0: Ring priority (0) 0 0 1
: Ring priority (1) 01h, : Ring priority (
2) 1” ha h+: Ring priority (3) In the above case, there are four levels of priority, with the lowest priority being “00”.
0". Frames with the lowest priority can be divided and transferred, but frames with other priorities cannot be divided and transferred. In other words, the number of priority levels that can be divided and transferred is one level. However, frames with a higher priority A frame with a high priority can interrupt a divided transfer, and the divided transfer is temporarily interrupted, a frame with a higher priority is transferred, and the continuation of the divided transfer is transferred again.

In addition, high priority is P3. The highest priority is p3=1, which corresponds to each bit of P,,P,. The first time you look at the bits from the MSB side, that is, the leftmost bit (P3) side.
The priority level is "l".

Additionally, if a high-priority reservation is made for the reservation index (described later) of the token or frame currently being transferred, the transmission source communication station issues the token or frame with a high priority. However, in this case, since "l" is simply set further to the left of the bit string of the priority before change, the priority before change should be kept as a history in the h l + h t part of the priority index mentioned above. I can do it. When the transfer of a frame with a higher priority is completed, the station that manipulated that priority removes the manipulated bit, returns it to the priority token in the history part, and releases that token. If there is no history, a token with ring priority '000' is generated.

(ii) T is the token bit, “0” in the token
”, and in the frame it becomes “l”.

(iii) M has a frame or ring priority of “00”
This is a monitor bit used to check to ensure that tokens larger than 0" do not continue to circulate on the ring.

(iv) Ri (i'' 1-3) is a reservation index bit indicating the reservation priority R.

Here, a specific example of the reservation index will be shown.

R, R, R.

0 0 0: No reservation 0 0 I: Reservation priority (1) 0 1 X: Reservation priority (2) I X
X: Reservation priority (3) However, even if X is “1”
This means that it may be 0".

Note that a communication station that has data with a high priority sets a bit corresponding to the priority among the reserved bits in order to acquire the right to issue the next frame. Then, the communication station that has collected the frame checks the bits of the reservation index of that frame and selects the priority (out of 3 bits) corresponding to that priority.
A token is issued in which the leftmost bit set) is set to the corresponding bit of the ring priority P.

That is, like the ring priority Pr, the reservation priority R1 is determined on the MSB side, that is, on the leftmost bit (R, +) side. Therefore, even if multiple bits are set in the reservation index, the leftmost bit is significant and the other bits are ignored.

(b) Frame control (FC) F, Fo Df Dns Dne SDs SDz 5
D(i)F + (+ = 1.2) is a frame indicator bit, "00" indicates a MAC (Media Access Control) frame of information for managing and maintaining the network, and "Ol" indicates an upper layer LLC. (Logical link control) frame, “IX” indicates that it is undefined.

(ii) Df is "0" to indicate a non-divided frame, and "1" to indicate a divided frame.

(iii) Dns and Dne are “o o” for undivided frame, “01” for first frame of divided frame, “I
"O" indicates the end frame of a divided frame, and "11" indicates an intermediate frame of the divided frames.

(iv) SDt (i = 1 to 3)) indicates data priority Pffi when Df = 0. Data priority Pyo is
Rather than a ring priority indicator for actual transfers on the ring.
Indicates the priority of the data itself.

The ring priority P is such that when data is transferred on the ring, data with a higher priority than the priority index of a token is transferred with the priority P1 of that token. For this reason, the priority of the data is not correctly communicated to the other party. Therefore, by giving the priority of the data itself to the data priority P0, the priority of the data can be conveyed to the transfer destination.

Furthermore, the data priorities P and R are the ring priorities P and R described above.
There are four types like r and reservation priority R1, “100
” is the most popular.

On the other hand, SDt(i=I~3)) indicates the division sequence number when Df=1. This is to check whether or not the divided frames are omitted during divided transfer.The first frame is "000" and 1
The value is increased by increments, and when it reaches "Ill", it returns to "000".

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a token ring type LAN according to an embodiment of the present invention. In this figure, 11 to 14 are communication stations that perform data communication with each other, and 2 is a communication station l, to I4. A transmission line such as a shielded twisted pair wire or optical fiber cable that connects the cables in a ring shape.

Here, a block diagram of the configuration of communication station I is shown in FIG.

In FIG. 2, 3 is a LAN connection unit, which is connected to the transmission path 2 and controls the reception of the signal SFT transferred from another communication station 1 and the transmission of the signal SFT transferred to the other communication station 1. do. 4 is a data processing unit, which processes the received data DR received and decoded by the LAN connection unit 3, and processes the received data DR received by the LAN connection unit 3 and other communication stations 1.
and processing of transmission data DT to be transmitted.

Further, in the LAN connection unit 3, 5 is a receiving unit that receives the signal SFT transferred via the transmission path 2, and 6 is a receiving unit that receives the signal SFT transferred via the transmission path 2.
A decoding unit decodes the frame/token bit string F/TBA from F and r, and 7 is a received bit analysis unit, which constantly inspects the frame/token bit string F/TBA and determines the start/end etc. of the frame/token bit string F/Tl 138. Detection of timing signal STM regarding ring priority P,
It also detects and generates the reservation priority R, and outputs the frame bit string FBA.

Furthermore, 8 is a reception control unit, and the frame bit string FB
Input A, judge whether this frame bit string FBA is addressed to the local station, and divide and transfer the frame bit string FBA.
B assembles the received data DT from A, and outputs the received data DR addressed to its own station.

9 inputs the received data DR, and controls the data processing unit 4 based on the reception control signal RCTL output from the data processing unit 4.
This is a received data output unit that outputs to.

In addition, 10 is a frame/token bit string F/TBA
A bit delay unit that rewrites bits while relaying the ! l is the transmission data D? output from the data processing unit 4 to be transmitted? and a transmission data input section which manually inputs the transmission control signal TCTL and outputs transmission data D7 based on the transmission control signal TCTL; 12 is a transmission control section which generates a token pit string TBA;
By outputting a data request signal DR to the transmission data input section 11 based on the transmission instruction signal TS and the transmission end signal TE output from the transmission data input section 11, the transmission data DT is inputted and a frame bit string FBA is generated. output according to the token ring protocol. This frame bit string FBA is generated based on the data priority P extracted from the transmission data D-r, the ring priority Pr1 reservation priority Rr output from the reception bit analysis section 7, and the timing signal STN. .

Also,! 3 is a transmission reservation unit, which inputs the larger of the reservation priority Rr output from the transmission control unit 12 and the data priority P (hereinafter expressed as a+ax' [Rr, Ps]); The reservation index bit RL of the frame/token bit string F/TBA that is passing through the bit delay unit IO corresponds to the leftmost bit among the three priority bits.
Set. 14 is the frame/token bit string F/TBA output from the bit delay 110 and the transmission control unit 1
Frame/token bit string P/token output from 2
This is a transmission selection unit that selects and outputs either one of TBA. Note that this selection is performed based on the selection signal S5ILL output from the transmission control section 12.

Furthermore, 15 is an encoding unit that encodes the frame/token bit string F/TBA output from the transmission selection unit I4;
A transmitter 16 transmits the output signal SFT of the encoder 15 to another communication station 1 via the transmission path 2.

In such a configuration, first, a case will be described where the communication station It divides and transfers data with data priority P, = '000'' to the communication station 13. Note that the boundary priority P+h is
Since the priority that can be divided and transferred is one level of "000", the priority is "000". Control of split transfer is
The transmission control unit 12 performs this.

The transmission control unit 12 of the communication station 11 determines that the data priority P□ of the transmission data DT generated in the data processing unit 4 and input through the transmission data input unit 11 is a priority “000”.
, and the transmission data length is the maximum length of one frame (1
If the length exceeds 36 octets), send data D. is divided and output as a plurality of frame bit strings FBA.

Note that the first frame bit string FBA of the divided transfer acquires a token using the data priority P1 extracted from the original transmission data DT, which in this case is the priority "000". That is, when the token joining priority Pr received by the receiving unit 5 and detected and generated through the decoding unit 6 and the received bit analysis unit 7 is priority “000”,
That is, if the ring priority P1 of the token is not greater than the data priority P of the local station, the station acquires the token. Furthermore, for the second and subsequent frame bit strings FBA, the data priority is set to the boundary priority Pt.
Change to h and output. However, in this case, since the boundary priority Pth and the priority that can be divided and transferred are the same, the data is output as is without being changed.

As a result, the communication station 1. which acquired the token circulating on the transmission path 2. obtains the right to transmit data on the transmission path 2, that is, the right to transmit data, changes the acquired token into a frame start sequence in the transmission control unit 12, and further changes the control field, address field, information field, and frame inspection. After adding the sequence and the frame end sequence, it is output as a frame bit string PBA together with a selection signal S sit. At this time, access control (AC) and frame control (
FC) is expressed as follows.

00010000...(AC) 01101000...(FC) Then, the frame bit string FBA output from the transmission control unit 12 is selected in the transmission selection unit 14, and after being encoded in the encoding unit 15, the transmission unit 16 via signal S
Sent as F□.

As a result, the signal SFT is transmitted from the communication station 11 to the neighboring communication station 1. will be forwarded to. The communication station l receives the signal SFT transferred via the transmission path 2 in the receiving unit 5, decodes it in the decoding unit 6, and then detects the timing signal 87.4 in the received bit analysis unit 7 and performs ring priority processing. It detects and generates the degree P and reservation priority Rr, and outputs the frame bit string FBA.

Furthermore, the reception control unit 8 determines whether the manually inputted frame bit string FBA is addressed to the own station. In this case, since it is not addressed to the own station, the frame bit string FB that was divided and transferred
The assembly of the received data DT from A and the output of the received data DT are not performed.

Next, the bit delay unit IO rewrites the bits while relaying the frame bit string FBA.

Now, communication station 1. Consider the case where there is transmission data DT to be transferred to the communication station 14 with data priority P and -"OOI". As a result, the transmission reservation unit 13
Input max[Rc, PJ outputted from Set in the corresponding position of bit Ri representing the reservation index.

Here, access control (AC
) is shown below. Note that "-" means that the bits are not changed. The same applies hereinafter.

■...(AC) Then, since data is not being sent from the local station at the moment, the frame bit string FBA output from the bit delay unit IO is selected in the transmission selection unit 14, and encoded in the encoding unit ■5. After that, it is transmitted via the transmitter 16 as a signal SFT.

Thereby, the signal SFT is transferred from the communication station 12 to the adjacent communication station 13. The communication station 13 receives the signal SFT transferred via the transmission path 2 at the receiving section 5, decodes it at the decoding section 6, and then detects the timing signal STH and determines the ring priority Pr and the received bit analysis section 7. Detection and generation of reservation priority Rr and output of frame bit string FBA are performed.

Further, the reception control unit 8 determines whether the input frame bit string FBA is addressed to the local station. In this case, since the data is addressed to the local station, the received data DR is assembled from the divided and transferred frames, and the received data DR addressed to the local station is output. Next, the reception data output section 9 inputs the reception data DR and outputs the reception control signal RCT output from the data processing section 4.
It outputs to the data processing section 4 based on L.

Next, the bit delay unit IO rewrites the bits while relaying the frame bit string FBA.

Communications station now! Consider the case where there is transmission data DT to be transferred to communication station 1 with data priority P1-“010”. As a result, the transmission reservation unit I3
may [Rr, P m] output from the frame/token bit string F/TBA that is passing through the bit delay unit IO is inputted with the value “■” set to the leftmost of the three priority bits. is set in the corresponding position of bit R0 representing the reservation index of .

Here, access control of the frame bit string FBA (
A specific example of AC) is shown below.

11 ・ ・ ・ (AC) Then, since data is not being transmitted from the local station at the moment, the frame bit string FBA output from the bit delay unit 10 is selected in the transmission selection unit 14, and is encoded in the encoding unit 15. After that, it is transmitted from the transmission path 2 via the transmitter 16.

Furthermore, since the operation of communication station I4 is similar to communication station I,
The explanation will be omitted.

Next, the communication station 11 detects and generates a ring priority P and a reservation priority Rr from the signal SFT transferred via the transmission path 2.

And communication station 1. The transmission control unit 12 of is notified from the received bit analysis unit 7 of the value of the ring priority P, in this case, the priority “000”, and the value of the reservation priority Rr, the priority “011”. Incidentally, now, the communication station 11 has data priority Pm=
Consider a case where only the transmission data D7 of "OOO" exists.

Therefore, among the reservation priority R1, the data priority P, and the ring priority P, the value of the reservation priority R is the largest, so J communication station 1. The transmission control unit I2 stops the divided transfer, sets the bit corresponding to the value of reservation priority R, in the ring priority index of access control (AC), and replaces all the bits of the reservation index with O. Token bit string TBA
Generate and output. Here, the token bit string TB^
A specific example of the access control all (AC) is shown below.

01100000...(AC) At this time, the transmission control unit 12 selects the bit corresponding to the changed priority among the bits of the changed priority P (3-bit structure Fj2) stored in the changed priority register. Set. In this case, it is "011".

By the way, communication station 1. is given priority “000” to communication station 13.
The transmission control unit 12 compares the values of the ring priority Pr, the reservation priority Rr, and the data priority P within the local station of the frame collected by the local station during divided transfer of the frame, and the ring priority is determined. The respective values of Pr1 reservation priority Rr and local data priority P are all "0"
00'', that is, if no reservation is made in other communication stations 1. to !4 and there is no high-priority transmission data D7 within the local station, divisional transfer is continued. A specific example of frame access control (AC) in this case is shown below.

10 0 0 0---(AC) Now, the divided transfer is interrupted and a new token bit string T
BA is generated - and its token bit string T B
As in the case of frame transfer described above, A is the signal SF? The communication station 1. The data is transferred from the communication station I to the communication station I and I. It is assumed that high priority reservations are not made in the communication station It.

And the communications station! 3 detects and generates a ring priority Pr and a reservation priority R1 from the token transferred via the transmission path 2.

Next, the transmission control unit 12 of the communication station 13 receives the value of the ring priority P1 from the received bit analysis unit 7, and in this case, the value of the ring priority “
011” and the value of the reservation priority Rr, in this case, the priority is “0”
Now, let us consider a case where only transmission data DT with data priority P and = "010" exists in the communication station 13.

Therefore, among reservation priority Rr1 data priority Pm and ring priority Pr, ring priority Pr and data priority P
1 are equal, that is, the ring priority P,
Since,is not greater than the data priority,P,, the communication station,l,acquires the token.

As a result, the communication station 13 obtains the transmission right, changes the acquired token into a frame start sequence in the transmission control unit 12, and further changes the control field, address field, information field, frame check sequence, and frame end sequence. After the addition, it is output as a frame bit string FBA together with the 1 selection value number S swL.

As a result, the frame bit string FBA output from the transmission control section 12 is selected by the transmission selection section 14, encoded by the encoding section 15, and then transmitted from the transmission path 2 via the transmission section 16 as a signal SFT. Here, a specific example of access control (AC) for the frame bit string FBA will be shown below. At this time, the frame bit string FBA
A bit of reservation indicator to know the latest status of the reservation,
All are replaced with 0. However, in this case, no reservations have been made, so no changes will be made.

toooo... (AC) As a result, the signal SFT is transferred from the communication station 13 to the adjacent communication station 14.

Then, after this signal SFT is transferred from the communication station 14 to the communication station l, which is the transmission destination, via communication station l, the operation in which the signal SFT is collected by the communication station l, which is the transmission source, is described in the above-mentioned division transfer. Since this is the same as in the case of , the explanation thereof will be omitted.

It is assumed that no reservation is made in any of the communication stations 1 during this frame transfer.

Next, the communication station 13 detects and generates a ring priority P and a reservation priority R from the token transferred via the transmission path 2.

Then, the transmission control unit 12 of the communication station 13 receives the value of the ring priority Pr from the received bit analysis unit 7, the value of the priority “011” in this case, the reservation priority R, and the value of the priority “R” in this case. ”
000'' is notified. Now, let us consider a case where communication station 1 only has transmission data DT with data priority P and −“000”.

Therefore, since the value of the ring priority Pr is the largest among the reservation priority Rr) data priority P and the ring priority Pr, the transmission control unit I2 of the communication station 13
, is used as is to generate and output a token bit string TBA in which the bit corresponding to the data priority level P is set in the access control (AC) reservation index bit.

Here, the access control (AC
) is shown below.

01100000...(AC) Next, when a new token bit string TBA is generated,
The token bit string TB^ is decoded and sent to the communication station 13 as a signal SFT, as in the case of frame transfer described above.
from there to the communication stations 14 and l. Also, the communications station!
4, it is assumed that high-priority reservations are not made.

And the communications station! , detects and generates the ring priority P and the reservation priority Rr from the token transferred via the transmission path 2.

Next, the transmission control unit 12 of the communication station I receives the value of the ring priority P, in the present case, the value of the ring priority P, in this case, and the value of the reservation priority Rr, in the present case, to the transmission control unit 12 of the communication station I. ,priority"
000'' is notified. Now, let us consider a case where communication station 1 only has transmission data DT with data priority P = ``000''. Also, change priority P3 is ``011''.

Therefore, since the most significant bit position of the data priority P□ where "I" is set and the respective positions of similar bit positions of the change priority P3, the communication station 11 first selects the change priority P, The ring priority Pr corresponding to the bit position of
and reset the change priority PX bit.

As a result, ring priority P,' = "001", reservation priority Rr - "000", data priority Pffi = "00"
0”, the change priority P becomes -”001”, and the communication station l,
After performing the same operation as the communication station 13 described above, it returns to the communication station II again, and at this time, the same operation as described above is performed at the communication station 1□.

As a result, the transmission control unit [2] determines the new ring priority P
Compare r with reservation priority R and data priority P. In this case, all of these have a priority of "000", so nothing is changed for them.

In addition, since the communication station 11 has suspended the divided transfer, the communication station 11 does not generate a new token bit string T EA.
Resume split transfer. Note that the operation of the divided transfer is the same as the operation described above, so the explanation thereof will be omitted.

Flowcharts of the operations when the communication station I receives a frame and a token are shown in FIGS. 3 and 4, respectively.

Furthermore, in the above case, communication station 1. For example, transmission data DT whose data priority P1 is priority "100"
When there is a ring priority Pr and a change priority P,
Among the respective bits, set the bit corresponding to the data priority P, and set all bits of the reservation index to 0.
Replace with

"Effects of the Invention" As explained above, according to the present invention, the following effects can be obtained.

■It is possible to construct it with one LAN both physically and protocol-wise.

■Real-time response performance is determined by the maximum frame length, not the token retention time, so it has excellent response performance.

■By keeping the maximum frame length small, real-time responsiveness can be improved without reducing the communication efficiency of large-scale data.

[Brief explanation of drawings]

FIG. 1 shows a token ring type LA according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of communication station I, FIG. 3 is a flowchart showing the operation when communication station 1 receives a frame, and FIG. 4 is a block diagram showing the configuration of communication station I. 3 is a flowchart showing the operation when a token is received. 1... Communication station, 2... Transmission line, 3...
... LAN connection section, 4 ... data processing section, 5 ... reception section, 6 ... decoding section, 7.
... Received bit analysis section, 8 ... Reception control section, 9 ... Received data output section, IO ...
・Bit delay section, 11... Transmission data input section,
12... Transmission control unit, 13... Transmission reservation unit, Wataru 4... Transmission selection unit, 15...
Encoding section, 16...Transmission section.

Claims (5)

[Claims] (1) A token ring LAN that includes a plurality of stations, a transmission path that connects the plurality of stations, a token for obtaining the right to transmit data that circulates in the transmission path, and a frame that holds and transports the data. The token has a ring priority storage area for storing the priority for data transmission, and the frame has a reservation priority storage area for storing the priority of data of each station, When the station receives a token circulating on the transmission path, it compares the priority of its own data with the ring priority and determines that the priority of its own data is higher. a frame generating means that does not transmit the token and transmits a frame that is the transmission data of the own station when the determination is made; data transmission reservation means that compares the priority with the reservation priority and writes the priority of the data of the own station in the reservation priority storage area of the frame when it is determined that the priority of the data of the own station is higher; and, while transmitting a frame that is the transmission data of the own station, the reservation priority of the recovered frame and the priority of the data of the own station are compared, and the reservation priority of the frame is determined. and a token generating means for generating a token having the reservation priority of the frame by stopping transmission of the frame which is transmission data of the own station when it is determined that the frame has a higher priority. Token ring type LAN. (2) A plurality of stations, a transmission line that connects the plurality of stations, a token for obtaining the right to transmit data circulating in the transmission line, and dividing the data into predetermined lengths. A token ring LAN having a frame for holding and transporting transmitted data, wherein the token has a ring priority storage area for storing priority for data transmission, and the frame has a ring priority storage area for storing priority for data transmission, and the frame has The station has a reserved priority storage area for storing data priorities, and when the station receives a token circulating on the transmission path, it compares its own data priority with the ring priority; Frame generating means for not transmitting the token and transmitting a frame that is transmission data of the own station when determining that the priority of the data of the own station is higher; and transmitting the data of the own station; When the data size of the own station is larger than a predetermined value, the data size is divided into pieces smaller than the predetermined value, stored in the data storage area of the frame, and the frame is sent out. data dividing means, when receiving a frame transmitted through the transmission path, compares the priority of the data of the local station with the reservation priority, and determines that the priority of the data of the local station is higher; When it is determined that the frame is transmitted, the data transmission reservation means writes the priority of the data of the own station in the reservation priority storage area of the frame; The reservation priority of the frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, the reservation priority of the frame that is the transmission data of the own station is compared. 1. A token ring type LAN comprising: token generation means for stopping transmission and generating a token having the reservation priority of the frame. (3) A plurality of stations, a transmission line that connects the plurality of stations, a token for obtaining the right to transmit data circulating in the transmission line, and dividing the data into predetermined lengths. A token ring LAN having a frame for holding and transporting transmitted data, wherein the token has a ring priority storage area for storing priority for data transmission, and the frame has a ring priority storage area for storing priority for data transmission, and the frame has The station has a reserved priority storage area for storing data priorities, and when the station receives a token circulating on the transmission path, it compares its own data priority with the ring priority; Frame generating means for not transmitting the token and transmitting a frame that is transmission data of the own station when determining that the priority of the data of the own station is higher; and transmitting the data of the own station; When doing so, if the priority of the data of the own station is lower than a predetermined value, the size of the data is divided into sizes smaller than the predetermined value, stored in the data storage area of the frame, and the frame is transmitted. data dividing means, when receiving a frame transmitted through the transmission path, compares the priority of the data of the local station with the reservation priority, and determines that the priority of the data of the local station is higher; data transmission reservation means for writing the priority of data of the local station in a reservation priority storage area of the frame; The reservation priority of the frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, the reservation priority of the frame that is the transmission data of the own station is compared. 1. A token ring type LAN comprising: token generation means for stopping transmission and generating a token having the reservation priority of the frame. (4) A plurality of stations, a transmission path that connects the plurality of stations, a token for obtaining the right to transmit data circulating in the transmission path, and dividing the data into predetermined lengths. A token ring LAN having a frame for holding and transporting transmitted data, wherein the token has a ring priority storage area for storing priority for data transmission, and the frame has a ring priority storage area for storing priority for data transmission, and the frame has The station has a reserved priority storage area for storing data priorities, and when the station receives a token circulating on the transmission path, it compares its own data priority with the ring priority; Frame generating means for not transmitting the token and transmitting a frame that is transmission data of the own station when determining that the priority of the data of the own station is higher; and transmitting the data of the own station; When the data size of the own station is larger than a predetermined value, the data size is divided into pieces smaller than the predetermined value, stored in the data storage area of the frame, and the frame is sent out. data dividing means, when receiving a frame transmitted through the transmission path, compares the priority of the data of the local station with the reservation priority, and determines that the priority of the data of the local station is higher; data transmission reservation means for writing the priority of data of the local station in a reservation priority storage area of the frame; The reservation priority of the frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, the reservation priority of the frame that is the transmission data of the own station is compared. token generation means for interrupting transmission, storing the reservation priority of the frame in the local station, and generating a token having the priority; Comparing the stored priority and the ring priority;
a priority operating means that restores the priority of the token operated by the local station to the original priority and restarts the interrupted transmission of the frame, which is the transmission data of the local station, on the condition that these priorities match; A token ring type LAN characterized by having. (5) A plurality of stations, a transmission line that connects the plurality of stations, a token for obtaining the right to transmit data circulating in the transmission line, and dividing the data into predetermined lengths. A token ring LAN having a frame for holding and transporting transmitted data, wherein the token has a ring priority storage area for storing priority for data transmission, and the frame has a ring priority storage area for storing priority for data transmission, and the frame has The station has a reserved priority storage area for storing data priorities, and when the station receives a token circulating on the transmission path, it compares its own data priority with the ring priority; Frame generating means for not transmitting the token and transmitting a frame that is transmission data of the own station when determining that the priority of the data of the own station is higher; and transmitting the data of the own station; When doing so, if the priority of the data of the own station is lower than a predetermined value, the size of the data is divided into sizes smaller than the predetermined value, stored in the data storage area of the frame, and the frame is transmitted. data dividing means, when receiving a frame transmitted through the transmission path, compares the priority of the data of the local station with the reservation priority, and determines that the priority of the data of the local station is higher; data transmission reservation means for writing the priority of data of the local station in a reservation priority storage area of the frame; The reservation priority of the frame is compared with the priority of the data of the own station, and if it is determined that the reservation priority of the frame has a higher priority, the reservation priority of the frame that is the transmission data of the own station is compared. token generation means for interrupting transmission, storing the reservation priority of the frame in the local station, and generating a token having the priority; Comparing the stored priority and the ring priority;
a priority operating means that restores the priority of the token operated by the local station to the original priority and restarts the interrupted transmission of the frame, which is the transmission data of the local station, on the condition that these priorities match; A token ring type LAN characterized by having.