RU2012042C1 - Device for control of access to bus in local area networks having bus architecture - Google Patents

Abstract

FIELD: computer engineering. SUBSTANCE: second counter 10, failure flip-flop 12, detach flip-flop 13, second comparison circuit 15, AND gate 16, OR gate 19, pulse shaper 20 are introduced in interface unit 2 to accomplish the goal of invention. This results in possibility to detach user from bus by right adjacent user if given user exceeds its time slice or is in faulty order. EFFECT: increased reliability due to exclusion of attach of other users when given user is serviced. 1 dwg

Description

 The invention relates to computer technology and can be used as a device for access control to the backbone when building local networks with backbone architecture.

 A device for interfacing subscribers with a common trunk, comprising a counter, a decoder, three triggers, two AND elements, two NOT elements, an OR element, a delay element, a one-shot [1].

 The disadvantages of this device are high hardware costs and low performance due to the complexity of the algorithm for resolving conflicts between subscribers to capture a common trunk.

 The closest in technical essence and the achieved positive effect to the invention is a device for controlling access to the backbone in local networks with backbone architecture, which contains a control unit, a control backbone, an information backbone and N interface units, and the control inputs and outputs of each interface unit are connected via a control the line to the output-input of the control unit, the first information inputs and outputs of each interface unit are interconnected through the information the highway, the i-th input of the device’s subscriber code (i = 1, N), the i-th input of the device’s request, the i-th information input-output of the first device group, the i-th information input-output of the second device group are connected respectively to the information input, to the control input, to the first information input-output and to the second information input-output of the i-th interface unit, while each interface unit contains a parallel code to serial converter, a counter, a comparison element and an And element, and in each interface block and the information input, control input, the first information input-output and the second information input-output of the interface unit are connected respectively to the first input of the comparison element, to the first input of the And element, to the first input-output and to the second input-output of the parallel code to serial converter, the counter output is connected to the second input of the comparison element, the output of which is connected to the second input of the And element, the control input-output of the interface unit is connected to the counter input of the counter and to the inverse output of the And element [2] .

 The disadvantages of such a device are low reliability and performance due to the hard algorithm of the access control device to the trunk and its hardware implementation. Low reliability of operation is due to the fact that in case of failure of the active subscriber during the exchange of information on the highway, access to it from other subscribers is blocked on the control highway until the subscriber is restored to working capacity. The low productivity of the device is due to the fact that the subscriber who has captured the control line can use it exclusively for unlimited time to the detriment of other subscribers, i.e., one request is served per unit of time.

 The aim of the invention is to increase the reliability and performance of the device.

 The goal is achieved in that the access control device to the backbone in local area networks with a backbone architecture, comprising a control unit and N interface units, the control inputs and outputs of each interface unit being connected through the control line to the inputs and outputs of the control unit, the first information inputs and outputs each pairing unit are interconnected via the information highway, the i-th input of the device subscriber code (i = 1, N), the i-th input of the device request, the i-th information input-output of the second group The devices are connected respectively to the information input, to the control input, to the first information input-output of the i-th interface unit, contains a parallel to serial converter, counter, comparison element, AND element, and in each interface unit there is an information input, control input, the first information input-output of the interface unit is connected respectively to the first input of the comparison element, to the first input of the element And, to the first input-output, the second input-output of the parallel converter An ode to the serial output of the counter is connected to the second input of the comparison element, the output of which is connected to the second input of the AND element, the control input-output of the interface unit is connected to the counter input of the counter and to the inverse input of the AND element, each interface unit additionally containing a second comparison unit , failure trigger, shutdown trigger, second information input, the direct and inverse outputs of which are connected to the second inverse input, the first and second control outputs of the interface unit, the first element And, the second m input connected to the clock input of the interface unit, the first input connected to the output of the second comparison unit, the first information input of which is connected to the output of the counter, the second element And, the output of which is connected to the installation input of the shutdown trigger, the first input of which is connected to the second control input of the interface unit as well as with the installation input of the failure trigger and the third control input of the AND element, the second counter, the input of which is connected to the output of the second comparison element, the OR element, the first control the input of which is connected to the overflow output of the first counter, a pulse shaper whose output is connected to the R-input of the second counter, and the control input to the output of the second counter and the second input of the second AND element, and in the control unit, the OR element is inverted output connected via the control line to the synchronizing input of the i-th interface unit, the i-th synchronizing input of the device, (i + 1) -th input of the subscriber priority code, i-th output of failure, i-th control output of the subscriber are connected respectively to the clock input, to the second information input, to the first control output, to the second control input, to the second control output of the i-th interface unit.

 The essence of the invention lies in the fact that for each pulse generated by the control unit, the bus is captured by only one interface unit. Capture is based on the sequence number of the pulse in the sequence, provided that the priority code matches the current code. At the time of service of this subscriber (transmission of bits of the information frame), connection of other subscribers of the main structure is impossible. The pairing unit is disconnected at the end of the reception-transmission cycle, when the time quantum allocated to the subscriber for the exchange of information is exceeded, in case of malfunctioning situations that increase the service time. In this case, the lock is removed from the control line. Disconnection is performed according to a certain algorithm by a neighboring subscriber located to the left of the active subscriber. It is possible to disconnect the subscriber on the right (while making minor changes to the device diagram). The invention is implemented due to a new set of elements and relationships, allowing to conclude that the proposed device meets the criterion of "novelty."

 The introduction of the second comparison unit and its connections allows you to identify the moment of disconnection of the pairing unit to subscribers, the priority code of which is equal to the current code. The introduction of the first element And allows you to generate a signal to set the second counter in a single state. The introduction of the second counter allows the control signal to be generated by the clock pulse to transfer the interface unit to the service mode for the shutdown request. The introduction of the pulse shaper and the OR element will allow the second counter to be reset to the desired state after the pairing unit is switched to the service mode for disconnecting the request, as well as in the event that the last subscriber ends in the network of the main architecture. The introduction of a failure trigger allows you to record the failure state of the interface unit and take it into account by the subscriber. The introduction of a shutdown trigger allows you to record a subscriber’s request for a shutdown and generate a control signal that removes the lock from the subscriber on the right side. The introduction of the second AND element allows you to set the shutdown trigger to a single state depending on the state of the second binary counter or the interface block adjacent to the right.

 The proposed device meets the criterion of significant differences, because in the analog devices, as well as in the prototype device, it is not possible to unlock the control line, i.e., turn off the active object that exceeds the exchange time or is in a failed state.

 When implementing the proposed device can be obtained a positive effect, which consists in increasing the efficiency of the access control device to the highway.

 The drawing shows a functional diagram of the proposed device.

 The device comprises a control unit 1, N interface units 2, a control line 3, an information line 4. The control unit 1 consists of a multivibrator assembled on OR elements 5-8, resistances R1, R2, R3 and capacitors C1, C2. Each pairing unit 2 consists of a counter 9, a second counter 10, a parallel to serial code converter 11, a failure trigger 12, a disconnect trigger 13, comparison elements 14, 15, a first element And 16, a second element And 17, an AND element NOT 18 open collector, OR element 19, pulse shaper 20 and has a clock input 21, control inputs 22-25, 28, outputs 27, 29, information inputs and outputs 26 and 30. The control unit 1 is connected to each unit 2 through inputs and outputs 21 , 22 and control line 3. The information highway 4 connects the information inputs / outputs 30 of the blocks 2 interface. In each block 2 pairing, the first information input 24, the control input 23, the first information input-output 26 are connected respectively to the first input of the comparison element 14, to the first input of the AND-NOT element 18 and the first input-output 26 and the second input-output 30 of the converter 11 parallel code to serial. The information output of the counter 9 is connected to the second input of the comparison element 14, the output of which is connected to the second input of the NAND gate 18. The control input-output 22 of the interface unit is connected to the counting input of the counter 9 and to the inverse output of the NAND gate 18, and the information output the counter 9 is connected to the first input of the second comparison element 15, and the second input of the comparison element 15 is connected to the second information input 25 of the interface unit. The output of the comparison element 15 is connected to the first control input of the element And 16, the second input connected to the clock input 21 of the pair 2, and the output to the information input of the second counter 10. The output of the second counter 10 is connected to the second control input of the element And 17, as well as the input of the pulse shaper 20, the output of which is connected to the second control input of the OR element 19. The first input of the OR element 19 is connected to the overflow output of the counter 9, and the output of the OR element 19 is the zero input of the second account ika 10. The output of AND 17 is a disabling input installation latch 13, inverted output connected to the second control output 29 interface unit 2. The second control input of the element And 17 is connected to the third control input of the element AND-NOT 18, the control input 28 of the interface unit and the installation input of the trigger 12 failure, the output of which is connected to the first control output 27 of the unit 2 interface.

The control unit 1 is designed to generate sequences of pulses that are transmitted through the control outputs 21, 22 along the line 3 to blocks 2.1-2. N pairing all subscribers. The interface unit captures the control bus, as well as disconnecting the subscriber from the trunk and receiving - transmitting information frames in serial-parallel code. The control line 3 is intended for the organization of conflict-free capture of the information line 4. The information line is designed to transmit bits of the information frame in a serial code between subscribers. Elements OR 5-8 are an integral part of the control unit 1 and are intended for the formation of control pulses of a certain duration and frequency. The counter 9 is designed to count the number of clock pulses coming from the control unit 1, the formation of the current code and the overflow control signal to its outputs. The counter 10 is designed to translate the pairing unit 2 into off mode and vice versa depending on the operating modes. The parallel to serial code converter 11 is intended for receiving and transmitting codes between subscribers through the information line 4, converting their parallel code to serial and vice versa. Failure trigger 12 is intended to form a sign of failure and transmit a signal to control output 27 to the subscriber. The shutdown trigger 13 is designed to set the shutdown mode in the pairing unit 2 and generate a control signal to disconnect from the subscriber on the left. Comparison element 14 is intended to compare the current code X _n with the priority code X _{i of the} subscriber of the receiving initiator — transmitting and generating a control signal allowing the capture of the control line. The comparison element 15 is intended to compare the current code X _n generated at the output of the counter 9 with the priority code X _{i-1 of the} subscriber performing the shutdown, and generate a control signal that initiates the transfer of the device to shutdown mode. Element And 16 is designed to generate from the clock pulse of the input 21 of the counting pulse of the transfer of the counter 10 to a single or zero state in the service mode of the shutdown request. Element And 17 is designed to generate an impulse to set the trigger 13 shutdown in a single state, provided that the counter 10 is in a single state, and subject to a single signal from input 28. Element I-NOT 18 with an open collector is designed to capture the control line 3 by shorting her from the exit of the element to the ground. Element OR 19 - designed to set the counter 10 to zero. The pulse shaper 20 is designed to generate a reset pulse counter 10 on the trailing edge of the signal at its output.

 The clock input 21 is designed to transmit synchronizing pulses from the output of the control unit 1 through the control line 3 to the pairing unit 2. The control input 22 is used to transmit pulses from the output of the control unit through the control line 3 to the input of the counter 9 of the pairing and blocking of the control line. Control inputs 23.1-23. N are used to transmit the control signal of the request of subscribers for the transmission of information in blocks 2.1-2. N pairing. Control inputs 24.1-24. N are used to receive priority codes from subscribers of the initiators of the reception - the transmission of information in blocks 2.1-2. N pairing. Control inputs 25.1-25. N are used to receive priority codes from subscribers disconnecting devices 2.1-2. N pairing. Information inputs and outputs 26.1-26. N are used for receiving - transmitting bits of information in parallel code. Control outputs 27.1-27. N are designed to transmit a control signal of failure, signaling the disconnection of unit 2 interfaces from the highway 3. Control inputs 28.1-28. N are intended for receiving a control signal from the interface block adjacent to the right, which signals a disconnection. Control outputs 29.1-29. N are designed to transmit a control signal to disable this pairing unit from the adjacent left on the highway. Information inputs and outputs 30.1-30. N are intended for reception - transmission of 4 bits of information in a serial code between subscriber interface units via the information highway.

 The device operates as follows.

 Block 1 generates a sequence of pulses that enter through the control line 3 to the control inputs 21, 22, blocks 2.1-2. N pairing all subscribers. Each pulse from the sequence allows the capture of the bus to only one pairing unit 2 according to the serial number of this pulse in the sequence. Thus, for capturing the information highway 4 by one of the subscribers, no more than N pulses are sufficient, where N is the number of subscribers in the network.

 At the time of capturing the highway 4 by one of the subscribers, block 1 stops the generation of pulses at the control input 22 and fixes the state in the counters 9.1-9. N. Pulse generation at control input 22 resumes if the trunk 4 is released by the subscriber who has captured it, or in the mode of disconnecting the subscriber from the trunk by another subscriber.

 The subscriber-transmitter, capturing the highway 4, transmits on it bits of the information frame. At the end of the reception-transmission cycle or at the end of the time interval provided for the subscriber to exchange information, the lock is removed from line 3 and block 1 continues to generate pulses at the control input 22.

The sequence of pulses received from the input of the counter 9 from block 1 is fixed at the output, and the current code is transmitted to the second information inputs of the comparison elements 14, 15. The first inputs 24, 25 on the second and third information inputs of the device receive codes X _i and X _i-1 , which determine the priority for disconnecting from subscribers in the network.

When the nth pulse arrives at the input of the counter 9, the current code X _n is generated at its output. If this code matches the priority code X _{i of the} subscriber requiring maintenance, a signal appears at the output of the comparison element 14, which is fed to the first input of the AND-NOT element 18. The subscriber requiring the service, together with the priority code X _i, sets a signal at the control input 23 transfer request From the control input 23, the request signal is supplied to the first input of the AND-NOT 18 element, to the third input of which an enabling potential is supplied from the control input 28 of the interface unit 2.

In the presence of these signals, the I-NOT 18 element with an open collector blocks trunk 3, shorting it to ground, which corresponds to the capture of the bus by the subscriber whose priority code is X _i . Capture of the bus by other subscribers is excluded, since trunk 3 is blocked, which means that the counters are in blocks 2.1-2. N pairings cannot change their state.

 The information of the subscriber-transmitter is converted from parallel code to serial using a converter 11 (K580IK51 circuit) and transmitted through line 4, from where it is input to a similar transceiver of the receiver subscriber unit 2.

 At the end of the information transfer session, the subscriber-transmitter removes the transmit signal from the control input 23, which means that the output of the AND-NOT 18 element with an open collector is disconnected from the line 3. This corresponds to unlocking from line 3 and the appearance of pulses at the output 22 of the control unit 1.

 The information transfer session by the transmitter-subscriber in the pairing unit 2 can be interrupted by another subscriber if, for example, the transmitter-subscriber exceeds the time of information exchange or in other cases. In this case, the active subscriber-transmitter is disconnected according to a certain algorithm by one of the pairing units 2 (in this case, the circuit provides for the disconnection of the subscriber-transmitter by the neighboring neighbor on the right).

 Disabling is as follows. The current code is received at the first input of the comparison element 15 from the output of the counter 9, and the priority code of the subscriber previous in the highway (the neighbor on the right) is received at the second input of the comparison element 15. When comparing the received codes at the output of the comparison element 15, a single signal appears which is gated by the first input of the And 16 element from the control unit 1 to the second input of And 16 through clock input 21. From the output of And 16 this pulse goes to the counter input 10 and sets it to a single state.

 A single signal from the output of the counter 10 of the block 2.2 interface through the element And 17 is fed to the input of the trigger 13 shutdown and sets it to a single state, which corresponds to a zero value of the signal at the inverse output of the trigger 13 shutdown.

 The zero level of the signal from the inverse output of the shutdown trigger 13 through the control output 29.2 is fed to the control input 28.1 of the interface block 2.1 adjacent to the trunk and sets the unit potential at the output of the AND-NOT element 18 of the pair 2.1, i.e., it removes the blocking of the trunk 3 by the pair 2.1 while allowing capture by other subscribers.

 On the trailing edge of the generated pulse at the output of the counter 10 of the pair 2.2, after a certain time interval formed at the output of the former 20, a pulse appears that produces a reset of the counter 10 to zero. The counter 10 is also reset in the case of servicing the last subscriber of the trunk, i.e., when an overflow signal appears at the output of the counter 9.

Upon receipt of an N-clock pulse at the input of the counter 9, block 2 is captured by the N pair of the control line 3. In this case, the priority code X _i must be equal to the current code X _n at the output of the counter 9. Block 2. N exchanges information through the converter 11 information line 4. At the normal completion of the exchange process, the subscriber removes the control signal from input 23. N and free the control line. The removal of the signal from input 23. N signals the end of the next cycle of the device, after which all the counters 9 and triggers 12, 13 of the coupler 2 are reset (zeroing circuits of the counters 9 and triggers 12, 13 are not shown).

 Compared with the prototype device, the claimed device provides a more reliable network operation, since a network failure can occur when two adjacent subscribers fail.

Provided that the probability of failure of one subscriber of the trunk P _open = 0.1, the probability of failure of the control device of the highway R _yy = 0.1, receive an increase in the probability of uptime of the network as a whole (reliability indicator) compared to the prototype device by 9%. To confirm this, use the formula
_Bp = P 1- _[yy · P (1- _(TCI P) ²⁾ + P _yy · P $\genfrac{}{}{0ex}{}{\text{2}}{\text{about}}$ _mk + P $\genfrac{}{}{0ex}{}{\text{2}}{\text{about}}$ _mk + (1-P _yy)] (1) where R 1 = _Br R _TCI = 1-0.1 = 0.9.

· 100%
(2) где Р_бру - вероятность безотказной работы сети с предлагаемым устройством;
Р_брп - вероятность безотказной работы сети с устройством-прототипом.In the formula (1) substitute the values of P _open and P _yy . Then
P _bp = 1- [0,1 · (1- (0,1) ² ) + 0,1 · (0,1) ² + (0,1) ² · (1-0,1)] = 1- 0.019 = 0.981
The gain in comparison with the prototype device is estimated by the formula
δP _br =

· 100%
(2) where P _bru is the probability of network failure with the proposed device;
R _brp - the probability of network failure with the prototype device.

· 100% = 0,09·100= 9%
Производительность сети (количество обслуженных в единицу времени запросов) по сравнению с устройством-прототипом увеличивается приблизительно в два раза, поскольку существует возможность обслуживания нескольких запросов за один и тот же промежуток времени.In the formula (2) substitute the values of P _bru = 0.981 and P _brp = 0.9. Then
δP _br =

100% = 0.09 100 = 9%
Network performance (the number of requests served per unit time) is approximately doubled compared with the prototype device, since it is possible to serve several requests in the same time period.

Claims (1)

 DEVICE FOR ACCESS CONTROL TO THE HIGHWAY IN LOCAL COMPUTER NETWORKS WITH MAIN ARCHITECTURE, containing the control unit and N interface units, the first information inputs and outputs of each interface unit are connected to the information highway, with each interface unit containing a parallel code converter, in the first, first counter comparison circuit, the first element And, the i-th input of the subscriber code of the device (i = 1, ..., N) is connected to the first input of the first comparison circuit of the i-th pairing unit, the first input p the first element AND of the i-th interface unit is connected to the i-th input of the device request, in the i-th interface unit, the first and second inputs-outputs of the parallel-to-serial converter are connected respectively to the first and second information inputs-outputs of the i-th interface unit, the output of the first counter is connected to the second input of the first comparison circuit, the output of which is connected to the second input of the first element And, the input-output of the control unit lock is connected through the control line to the counting input of the first counter and inverted at the output of the first And element, characterized in that, in order to increase the reliability of the device by eliminating the connection of other subscribers at the time of service of this subscriber, each interface unit additionally contains a second comparison circuit, a second and third I element, a second counter, a failure trigger, an element OR, pulse shaper, shutdown trigger, and in the i-th interface unit, the direct output of the failure trigger is the i-th output of the device failure, the inverse output of the disconnect trigger of the i-th interface unit (j = 1 and N-1) is connected to the S-input of the failure trigger and the third input of the first element AND (J + 1) -th interface unit, the first input of the second element And is connected via the control line to the clock output of the control unit, and the second input is connected to the output of the second comparison circuit, the first input of which connected to the output of the first counter, the output of the third AND element is connected to the S-input of the shutdown trigger, the counting input of the second counter is connected to the output of the second AND element, the first input of the OR element is connected to the overflow output of the first counter, the output of the pulse shaper x is connected to the second input of the OR element, the input of the pulse shaper is connected to the output of the second counter and the first input of the third AND element, the second input of which is connected to the S-input of the failure trigger, the second input of the second comparison circuit is connected to the i-th input of the priority code of the previous device subscriber , the output of the OR element is connected to the R-input of the second counter, the output of the shutdown trigger of the N-th interface unit is connected to the S-input of the failure trigger and the third input of the first element AND of the first interface unit.