SU1429119A1 - Device for measuring time-related parameters of a station - Google Patents

Abstract

The invention relates to computing and can be used in mono-channel local area networks with a random number. The data access medium to control the time parameters of the station during their debugging and operation. The goal is to expand the functionality by allowing the station to control the reaction during a collision by detecting arbitrary violations of its time parameters. The device contains a data receiving unit, an encoder, a control unit, a collision signal receiving unit, a receiving mode unit, a transmission unit, two triggers, a pulse shaping unit, two AND elements, an OR element, a waiting time counting unit, a force counter, a number counter collisions, memory block, buffer register, pulse generator. The device provides the ability to measure rnovnyh. temporal parameters of the station and thus allows the monitoring of the temporal parameters of the station during its operation in a monocal network, as well. and debugging the station autonomously in the collision simulation mode. 1 hp f-ly, 7 ill. $ W with

Description

; The invention relates to computing technology and can be used in mono-channel local high-end networks with a random access method to the data transmission medium to control the temporal parameters of stations during their debugging and operation.

The purpose of the invention is to expand (the functionality due to the lack of monitoring the reaction of the station 3 by the collision process. You can detect arbitrary violations of its temporal parameters.

Fig. 1 shows a functional diagram of a device for measuring station time parameters; 2 shows time diagrams illustrating the operation of the device when measuring time parameters; Fig. 3 is a functional block diagram of a time counting block I wait; Fig. 4 are timing diagrams illustrating the operation of the waiting time counting unit; Fig. 5 is a block diagram of the control unit; Fig. 6 is a block diagram of the reception mode; Fig. 7 shows the connection modes of the measurement device to the station.

A device for measuring time parameters (Fig. 1) comprises a data reception unit 1, an encoder 2, a control unit 3, a collision signal reception unit 4, a reception mode unit 5, a first trigger 6, a transmission unit 7, a pulse generation unit 8, the first element AND 9, the element OR 10, the standby time counting unit 11, the counter 12, the force time, the collision number counter 13, the second trigger 4, the second element 15, the memory block 16, the buffer register 17 and the pulse generator 18.

In Fig. 1, information input 19, collision input 20, mode setting input 21, synchronization input 22, input 23 of the gateway and collision simulation output 24, information output device 25 are indicated.

In Figure 2, the following definitions are accepted: C is the synchronization signal from the output of the encoder 2; H - signal Media from the output of the encoder 2; nN; - signal of the beginning of the signal. The carrier at the first output of the pulser 8; nN is the signal of the beginning of the signal. The carrier is at the second output of the pulsing unit 8; kN - signal of the end of the signal

the third output of the pulse shaping unit 8 ;. Qe signal at forward trigger output 6; Totkl time delay; . - time of forcing.

The standby time counting unit 11 (FIG. 3) contains a delay time counter 26, a trigger 27, an AND element 28, a basic interval time counter 29, a pulse shaper 30, a basic interval repetition counter 31

In Fig. 4, the following notation is accepted: H is the signal Carrier, the signal at the output of the trigger 27j tjoa is the delay time; tdaj is the time of the base interval, the life time of waiting, g is the number of repetitions of the base interval.

The control unit 3 (FIG. 5) contains the shift register 32, the AND 33 element, the trigger 34 and the AND 35 element.

Unit 5 of the reception mode (FIG. 6) maintains the element NOT 36, the elements AND-NOT 37 and 38.

FIG. Figure 7a shows the collision simulation mode, when the device for measuring time parameters, which is an integral part of the local network tester, is connected directly to station (C), and on. 4) ig.7b - the tester is included in the interface of the station (C) - access block (DB), in this case, the time parameters of the station can be monitored during a real collision in the mono channel. when trying to transfer.

As a block 4 for receiving a collision signal (the collision signal arriving at the device input 20, there can be a sequence of pulses with a certain frequency), you can use a circuit containing a pulse detector and a detent (for example, a trigger). As a transmission unit 7, a delayed multivibrator circuit can be used, which begins to generate pulses at the device output 24 after the enable signal arrives at its input from the first output of the reception mode unit 5. As a pulse shaping unit 8, a circuit is used containing the first driver, the output of which produces a pulse (nN) from the leading edge of the input signal. The carrier, the second driver generating a pulse from the falling edge of the pulse of the first generator.

; 314

l (nN), and the third pulse shaper, at the output of which (kN) appears from the trailing edge of the input signal Carrier.

The most important condition for ensuring successful data exchange and the maximum possible throughput of a mono-channel when stations operate on a local computer network with random access is accurate observance of stations participating in a collision (in a collision of simultaneous transmissions of two or more stations) of the established time characteristics of retry attempts data transmission for each station. As noted, such characteristics primarily relate to the delay time of frame retransmission () which is different for each station participating in the collision. This delay interval is composed of the following components:

 -OtK / y

. - Tjoft + TYROM. Tozh, (1)

where is the delay time (or the time of the interframe interval), the value is constant and equal to the minimum mash interval of 9.6 µs for f 10 MHz and 20 МКС for f MHz;

Tqaopc forcing time, the value of which ranges from 3.2 to 4.8 MKS for f 10 MHz and 9 to 12 MKS for f 1 MHz ;.

The latency time is a random time interval, defined as

Tozh tipa g, (2)

where tgQj is the base time interval equal to 51.2 MKS at f 10 MHz and 128 MKS at f 1 MHz;

g is the number of repetitions of the base interval, which is chosen randomly for each station with a uniform distribution within, where k is the limiter of the exponent of postponing transmissions, which can be, for example, within 2 k, n is the sequence number of the next frame transmission attempt (in mono-local area networks, the number of attempts is limited: n, 16).

Two modes of use of the device for measuring station time parameters are possible: the mode of simulating a collision in a mono channel (for debugging, station) and the mode of measuring

time parameters of the station during the actual data transmission with collision (to monitor the time parameters of the station during operation). In the first case, the device is connected to the station via a data line (input 9) and a control line (output 24). In the second case, the device is connected to the Station interface — a block of access to the local computer network through a data line (input 19) and a control line (input 20

In the collision simulation mode, the collision signal receiving unit 4 is disconnected from the corresponding station facilities, and an O signal defining the receive mode of data with collision simulation is set to the device input 21 (respectively, signal 1 determines the reception of the collision signal on the fly 20 from the access unit two ). In block 5 of the reception mode,

 According to FIG. 6, this signal is fed to the inputs of the elements HE 36 and N-37. The output of the element is NOT signal 1

 is resolving for element 38. In addition, it is fed to the third output of the unit and from there to the third input of the control unit (Fig. 1). At the input of the NE-37 element, the signal O is a prohibitive 11M, and the output of this element will be a constant unit.

After setting the signal O on the input 21, the frame received from the station is fed to the input 20 of the device, i.e. on the input unit of the data receiving unit, in which it is matched and converted by the level and from the output of the data receiving unit, is fed to the input of the encoder 2. In the encoder 2, the data received in the Manchester self-synchronizing code are converted into a digital code in such a way that the output of the encoder 2 receives data, the second output receives synchronization signals, and the third code contains data availability signals (Signal Carrier). At the same time, the Signal Carrier enters the input of the pulse shaping unit 8, the third input of the first element 9 and the first input block 1 latency accounts; the synchronization signal from the output of the encoder 2 is fed to the second input of the control unit 3 and to the second input of the And 9 element; the sequence of signals from the data output of the encoder 2 is fed to the first

514

input of control unit 3, in which, after passing the preamble octets; the frame and when pasting the two last bits; 1 octet of the limiter; the beginning of the frame (PMC) is formed; Nal 1. In this case, in block 3 of control (Fig. 5), the frame data signals are input to the shift register 32. The clock pulses are input to the register synchronization input. The information is shifted, and as soon as the two adjacent {units from the PMC floor are shifted | to the 7th - AND 8th register bit, the trigger 34 is switched by a signal from the output of element 1, 33 switches, and to the second input | The second element, And 35, is set to | one. In this mode I (simulation), the first input of the element | I 35 from the block 5 of the receiving mode also I receives a unit.

I The signal 1 from the output of the element 35 (output) of the control unit 3 is fed to the second installation input of the trigger 6 and switches it. The signal from the direct output of the trigger 6 (differential 0-1) is a signal to simulate a collision in the mono channel and enters the first input of the first element AND 9 and the third input of the reception mode unit 5, in which (figure 5) upon receipt of this the signal to the input of the element 38 and the latter switches (since the second input of the element is already set to 1), and the signal from its output (differential 0-1) —the output of the reception mode unit 5 — is fed through the transmission unit 7 to the output 24 of the device and to the station. When this signal arrives at the station, the latter perceives it as a signal of a collision in the mono channel and should respond to it in accordance with the received protocol, i.e. force and stop data transmission, and then through time Tot-il determined at each next attempt, make the next attempt to transmit a frame.

Simultaneously from the inverse output of the trigger 6, a signal with a 1-0 difference through the element OR 10 acts on the counting input of the counter 13 of the number of collisions, in which the first collision simulated in the mono channel is recorded (row Collision, Fig. 2).

During the forcing of the transmission by the station, i.e. the moment of arrival of the signal

one

-

five

96

Hera 6 (line O, Fig. 2) at the output 24 of the device and at the first input of the first element I 9 and until the station stops transmitting (line kN, Fig. 2), the sync signals from the sync output of the encoder 2 go through the element 9 through the counting the input of the forcing time counter 12 (on the other inputs of the And 9 element there are already signals 1 from the outputs of the signal Encoder 2 and the direct output of trigger 6). The counter 12 stops the clock from the output of the encoder 2, i.e. finishes the measurement of the Tchedr 1 forcing time, at the time of the removal of the Carrier signal (row Counter 12, Fig. 2). This moment is determined by the station stopping the data transmission and is characterized by the absence of data signals, synchronization and the Carrier at the outputs of the encoder 2. Signal Removal The carrier, which is prohibited for the forcing time counter 12, is simultaneously the resolution for the waiting time counting unit 11: from now on in block 11, the counting of the clock pulses arriving at its third input from the input 22 of the external synchronization of the device begins.

In block 11, counting the waiting time after a time expires, a delay equal to the minimum interframe interval (9.6 µs for f 10 MHz or 20 ISS for f 1 MHz), the time TO is measured according to formula (2) by counting the number g repetitions of the base interval.

In accordance with the above measurement algorithm, the operation of the waiting time counting unit 11 is characterized as follows. On admission: from the code of the pulse shaping unit 8 (Fig. 1) of the nN signal generated in block 8 on the falling edge of the nN signal, the counter 26, 29 and 3J and the trigger 27 of the J1 block (Fig. 3) are reset. During the reception of the frame, as long as the carrier signal (from the output of decoder 2, Fig. 1) arrives at the first input of the waiting time counting unit 11, the operation of this block is prohibited. At the end of the reception of the frame (as a result of the station stopping its transmission by the signal Collision), the ban on the input of the control of the delay time counter 26 is removed, and

the counting of the sync pulses of a certain frequency (e.g., 10 MHz) starts at the input of the counter 26 from the input 22 of the external synchronization device. The end of count pulse appears at the output of the counter 26 after the delay time TmA (figure 4), the value of which, as previously indicated, is constant and can be pre-programmed by selecting the appropriate output of the delay time counter 26. The impulse from the output of the counter 26 of the delay includes the trigger 27, and the signal from its output prohibits further operation of the counter 26 and at the same time entering the input

element And 28, allows the passage of clock pulses from the input 22 of the device through this element to the input of the counter 29 of the time of the base interval. Like the delay time counter 26, the counter 29 is also tunable, since the duration of the base interval, as previously indicated, may be different. The signal of the windows 1 and the counting of the time of the first counter 29 of the speed indicator is applied to

the input of the imager .30 pulses, the output of which is from the leading edge

j of the input signal, a resetting pulse is generated by the base time counter 29 and simultaneously arriving at the input of the base interval repeat counter 31, in which the first time interval tsui is fixed. Further, the counter 29 of the time of the base interval again counts

the sync pulses arriving at its input from input 22 until the counting time becomes equal, and then the second tetxj time counting signal from the output of counter 29 is again fed to the input of the driver 30, the output pulse of which resets the counter again

29 to the initial state and will be fixed in the counter 31 as the second time interval t and%. Further in the repeat counter 31 the number r (figure 4), characteristic of the time of waiting to wait after the collision, will be fixed. The number of pulses arriving at the counting input of counter 31 after the next simulation of a collision is different, therefore, the total waiting time is also different. Sync pulse count

0

five

0

five

0

five

0

five

0

five

from the input 22 of the device, continues in block I1 of the waiting time counting unit I1 for the time interval determined by the time characteristics of the station, i.e. from the moment of termination of the next attempt to transfer the frame to the beginning of the next one. After this interval has elapsed, a frame transmitted by the station re-arrives at the device 19 (figure 1), the data of the synchronization data and the carrier appear at the outputs of the encoder 2, and the signal appears at the first input of the time counting unit 11 waiting forbids his work. Thus, at the time of the prohibition of the account, in block 11, the time will be fixed and measured or, according to formula (1), Totkle time without taking into account the T-pope time. , The measurement result of iotor was previously obtained in counter 12.

When a new frame appears, the Media signal also enters the input of the pulse shaping unit 8, in which a nN pulse is generated on the leading edge of this signal from the first output of the pulse shaping unit 8 to the input of the second element 15, to the second input of which the enable signal is sent the output of the second trigger 14. As a result of the signal from the output of the element 15 on the recording input of the memory block 16 to the last, data is written from the outputs of the forcing time counter 12 and the block 11 of the waiting time count; The data input to the memory block 16 from the counter output of the collision number 13 is simultaneously the address for the packet block 16, which records the presence of the first collision and the time parameters characterizing the station's response to the signal. collision and measured in the counter 12 forcing time and block; 11 waiting time accounts.

In block 8 of forming pulses on the falling edge of the signal nN (i.e. after writing the contents of counter 12 and block 11 into memory block 16), the signal HKg- is formed (Fig. 2), upon receipt of which from the second output, block 8 to the inputs resetting the standby time counting unit 11 and the forcing time counter 12, in these blocks the initial state is set.

At the same time, as with the first attempt to transmit a frame, a sequence of signals from the data output of the encoder 2 is fed to the corresponding input of control unit 3 and a signal Collision is generated by the last two bits 11 octets of the ONC, which switches trigger 6, and the signal is transmitted to the station simulating a collision in a mono channel, the station forces and stops transmitting the frame and the process of measuring the temporal characteristics of its response to the collision signal is repeated: a second collision is recorded in the counter 13, . counter 12 — time of forcing; and in block 1 1 — time of waiting, the corresponding second attempts for transmitting the frame were transmitted. After measuring these parameters at the time of the beginning of the next (third) frame transfer attempt, the measurement results are recorded in the second cell of the memory block 16.

The measurement cycle of the station time parameters and their recordings in the memory block 16 stops after the number of frame transmission attempts reaches the maximum possible (for example, 16). When counting 16, the counter output signal 13 for the number of collisions through the trigger 14 and the second element J 15 is prohibited from writing to the .16 block of memory. Data transfer from the memory block 16 through the buffer register 17 to the output 25 of the device to the common bus (for further processing and analysis) is performed by applying a read signal to the device 23. On the leading edge of this signal, arriving through the IL 10 element at the input of the counter 13, the number of collisions, the counter 13 triggers, and from its output to the inputs of the memory block 16 and the buffer register 17, the address of the first cell of the memory block 16 is set, from which From the output of the imaging unit 18, formed on the trailing edge of the Read signal, the measurement results of the time parameters corresponding to the first collision are read. As a result of the repeated signal supply, Readout from output 25 to the common bus will read all information and stored in the memory unit 16.

Thus, when debugging a station (not included in the LAN, FIG. 7a)

five

using a measuring device, collisions in the data transmission medium are simulated and the station time parameters are monitored — the number of collisions, the delay time, and the forcing time is measured directly by counting pulses with a calibrated period and waiting time by counting the number of pulses corresponding to the number of years. with a calibrated period equal to.

The differences in the operation of the device in the mode; The measurement of the time parameters of the station during the actual data transmission with the collision is that the collision signal is received; It goes to the device input 20 from the outside via the control line from. block access (Fig. 76). In this mode, a device for measuring time parameters is connected to the interface unit for accessing data lines (input 19) and control (input 20). The operation of the device in this mode is as follows. Input 21 sets the / gc signal

V

Stations start re0

3

0

five

0

five

giving frame in the mono channel to another station. If a collision occurs in the mono channel, then a generator is turned on in the database, and the control circuit sends a pulse with a frequency, for example, 5 or 10 MHz, as is the source of the station, tick and measurement devices. The station's response should be the same as before when the same pulses are transmitted to the station at exit 24 with the same frequency from transmission block 7: transmitting the transmission and stopping it until a new attempt to transmit the message to the mono channel. In the measurement device (Fig. 1), the received signals are recorded in block 4 for receiving a collision signal. The latching signal H from the output of block 4 is fed to the first input of block 5 of the reception mode (Fig. 6), to the second input of the element. AND-NOT 37, at the output of which, and consequently, the second output of block 5 of the mode, an O signal appears that switches the trigger 6. After switching it, the operation of the measuring device does not differ from its operation in the collision simulation mode: the counter 13 is triggered the number of collisions, the counter 2 of the formation time begins to work, and after the transfer has ceased (i.e. after the signal is removed, the carrier from the output of the encoder 2)

and block P of the waiting time count. To prevent the first installation input of trigger 6 from the control unit 3 from entering the collision signal (which is used in the simulation mode) from the third output of the reception mode unit 5, the inhibit signal O comes to the third input of the control unit 3 (in FIG. element 36 to the input element And 35 in figure 5). In addition, in block 5 of the reception mode, the same signal O blocks the switching of the element 38 and (6) after switching the trigger 6 and thus on the input of the transmission block 7 a signal O is maintained preventing the operation of the transmission block 7.

A further process of monitoring and measuring station time parameters if a collision occurs in a mono channel, occurs as described above — the measurement results stored in memory block 16 via the buffer register 17 are output to a common bus for further processing and analysis. .

Thus, the device provides the ability to measure the main time parameters of the station in both modes of its use and

thus, it is possible to control the time parameters of the station both during its operation in a mono-channel network and to debug the station autonomously (in the collision simulation mode). The subsequent processing and analysis of the measurement results recorded in memory block 16 allows

It is possible to reveal arbitrary violations of the time characteristics of the station, if necessary, exclude from the network those stations where the values of deviations from the normal characteristics are given and,

ultimately, increase local area network performance

Claims (2)

1. A device for measuring station time parameters containing an encoder, a control unit, a memory unit, a buffer register and a pulse shaper, the device receiving data input connected to the encoder input, the first and second codes of which are connected respectively to the data and synchronization inputs of the unit g 0 5 0 five 0 five 0 five 0 five control, the output of the memory unit is connected to the information input of the buffer register, the read input of which is connected to the output of the pulse former, the input of which is the read input of the device; the output of the buffer register is an information output of the device, which is such that, in order to expand its functionality by ensuring control of the station's response during a collision of transmissions by detecting arbitrary violations of its time parameters, it is entered into the device. the receive mode block, the forcing time counter, the standby time counting unit, the count number of the first and second triggers, the pulse trigger unit 5, the I-rOJ-i element, the first: m and the second element And the input of the mode mode of the prig1oa mode connected to the input of the setting mode of the device, the information ROCKET of the receiving mode is connected: to the input of receiving the signal of the collision: 1and the device, and the input of the setting of the pescin-ia block of the receiving mode is the input of setting the setting of the device, informational input and input strobe block mode mode n iema soedt; p: ep; respectively, with the reception input of the collision signal of the device, the direct output of the first trigger, the first, the ETO and the third outputs of the receive direction blocks are respectively connected to the synchronization input of the first trigger, the building output of the control unit and the output of the collision simulation, the sync, reset and enable inputs the counting time counting unit accounts are connected respectively to the device sync input, the first output of the pulse shaping unit and the third input of the encoder, the information output of the counting unit is Waiting is connected to the first data input of the memory unit, the second data input of which is connected to the information output of the forcing time counter, the information output of the collision number counter is connected to the address inputs of the memory block and the buffer register, the third encoder stroke is connected to the input of the pulse shaping unit and the first the input of the first element And, the second and third inputs of which are connected to the second output of the encoder and the single output of the first trigger, the input of the initial installation and the counting input The forcing time counter is connected respectively to the first output of the pulse shaping unit and the output of the first element, AND, the overflow output of the number of collisions is connected to the single input of the second trigger, the direct output of which is connected to the first input of the second element AND, the second input and output of which connected, respectively, to the second output of the pulse shaping unit and the recording input of the memory unit; the output of the NL unit is connected to the counting input of the collision counter, the first and second inverse inputs of the OR element By connecting respectively to the inverse output of the first flip-flop and to an input sensing an apparatus, and a single zero inputs the first trigger is connected respectively to the third output of the pulse shaping unit and the output of the control unit, 2. The device according to claim 1, characterized in that the control unit contains a shift register, a trigger, two AND elements, the information input and the shift register shift input being a data and synchronization input of the block, respectively, the seventh and eighth shift register bits are connected respectively, the first and second inputs of the first element And, the output of which is connected to a single trigger input, the direct output of which is connected to the first input of the second element And, the second input and output of which are respectively enable and and output of the unit. 22 External Shn} (Roniza14 B25 9g.1 HHi Ht K / f fhwffiSf Ctet i2 (22) - (i) BHeutti. cuHfp. n F (Y FIG. (five) (2) (2) M VAC (s) Vu.z.5 W (7) ig.v 542 D }