JPH07250073A - Relay transfer method and relay transfer device for flow control information - Google Patents

Abstract

PURPOSE:To provide flow control information relay transfer method and device capable of effectively using a transmission line and minimizing delay at the time of transferring flow control information. CONSTITUTION:In this flow control information relay transfer method, the processing of a destination node is provided with a measuring process for measuring a burst arrival minimum interval from a prescribed interface, a counting process for counting the number of ready pulses arrived within the measured burst arrival minimum interval and a processing process for encoding the count value and transferring it as a data unit different from user data by a relay network when the count value of the ready pulses arrived within the burst arrival minimum interval is positive, waiting for the arrival of the ready pulse further when the count value of the ready pulses is '0' and encoding the count value of the ready pulses and transferring it as the data unit different from the user data by the relay network immediately after the arrival.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay transfer method and a relay transfer device for flow control information.

[0002]

2. Description of the Related Art There are ATM networks, frame relay networks, public packet networks, etc. as networks for relaying the HIPPI interface. The HIPPI interface (800M
Bps) is relayed by an ATM network (622.08 Mbps). FIG. 8 is a diagram showing a protocol stack when the HIPPI interface (HIPPI-PH) is connected to an ATM network, and FIG. 9 is a diagram showing a flow of user data and flow control information in that case. .

In the figure, the source and destination ends indicate terminals such as computers, which are connected to the HIPPI interface. Reference numeral 100 is a data processing unit, and 101 is a flow control unit. In HIPPI (-PH),
Data is transferred in units of fixed-length (1 kbyte) data called a store. Since the transmission rate is a fixed value of 800 Mbps, the minimum interval for the burst to reach the destination node is 10 microseconds. In HIPPI, if the data destination end can receive 1 burst,
By sending one ready pulse through the ready signal line, which is one of the signal lines, the source end is notified that it is receivable, and the flow of data from the data source end is controlled. Due to the large burst size of 1 kbyte, the destination end can send multiple ready pulses within the minimum burst arrival time.

On the other hand, the ATM network uses a protocol different from HIPPI, the data unit is called ATM cell, and its length is fixed to 5 bytes for header and 48 bytes for payload. In the ATM network, the user data is processed by the data processing unit 100, the ready pulse is processed by the flow control processing unit 101, and transferred as different cells.

First, the flow of user data is as follows. The sender end sends a burst which is a data unit of HIPPI through the HIPPI interface. At the sender node, the burst received by the data processing unit 100 is divided into a certain length, and the adapter is adapted. -Transaction processing ATM
It is stored in a cell and transferred. At the destination ATM node,
The information processing part 100 extracts the information part from the ATM cell received and assembles the burst. The assembled burst is passed to the destination end through the HIPPI interface.

In addition to the flow of user data described above, there is a flow of flow control information in the opposite direction. At the destination end, burst transmission (flow) at the source end is controlled using the HIPPI flow control method. At the destination end, if a new 1 burst can be received after setting the connection, 1 ready pulse is transmitted. However, HIPP
The I (-PH) specification allows the destination end to send up to 63 more ready pulses than the number of received bursts.
At the source end, transmission of one burst per one ready pulse is permitted. At the source end, the number of transmittable bursts decreases by 1 for each burst transmission, and the number of transmittable bursts increases by 1 every reception of one ready pulse. When the reception data processing at the destination end is slow, the ready pulse may not reach the source end fast enough, and the source end may have to stop transmitting the burst.

FIG. 10 shows the operation in the conventional method. The vertical axis represents time, and the horizontal axis represents physical position. When the source end sends a burst, it reaches the source node after some time. The source node divides the received burst, stores it in a plurality of cells, and transfers it. The destination node assembles the burst from the received multiple cells, and HIPPI
Pass the burst to the destination end through the interface.
Although the flow control method by HIPPI at both ends is fixed, various methods can be considered for the flow control information relay transfer method in the ATM network including the processing of the destination / source node.
Depending on the scheme, the destination end may be able to receive the burst, but the source end may need to stop burst transmission unnecessarily because the ready pulse does not arrive.

As a conventional technique of a flow control information transfer method in an ATM network, a method of transmitting flow control information by a cell each time a ready pulse is received in a flow control process at a destination end will be described. In the ATM network, a cell indicating that one ready pulse has been received (called a ready cell) is created, and the ready cell is transmitted every time the destination node receives the ready pulse from the destination end.

The operation of only the destination node in FIG. 10 is shown in FIG. The horizontal axis represents time, and indicates that the ready cell is transferred to the ATM network side each time the ready pulse is received from the HIPPI side.

In the flow control process of the source node, when the ready pulse is received from the destination node, the ready pulse is immediately passed to the source end. By processing in this way, the ready pulse transmitted by the destination end is transferred to the relay ATM.
The source end is reached via the network and the HIPPI flow is reached.
The control can work.

[0011]

There are the following two problems in the flow control information relay transfer system. First, it was not possible to reduce the delay time of the flow control information transfer. If no ready pulse arrives within the minimum burst arrival interval, the number of transmittable bursts decreases by 1 at the source end, and there is a possibility that transmission is stopped at 0. . At this time, if the destination end cannot actually receive the burst, there is no problem, but there is a possibility that the source end may stop the transmission due to the delay due to the flow control information relay transfer method. Therefore, if no ready pulse arrives within the minimum burst arrival interval, the destination node should forward the next ready pulse to the source end as soon as possible. The point was not fully considered.

Secondly, it is important to keep the ratio of the flow control information occupying the transfer path as low as possible. The relay ATM network is shared by a plurality of end users, and network resources such as bandwidth should be provided to users as much as possible. The same is true for frame relay networks, public packet networks, etc. However, in the prior art, each time the destination node receives a ready pulse, a ready cell indicating reception of one ready pulse is sent to the source node.
In the ATM network, the flow control information occupies the transmission line more than necessary, and the ratio of the transmission line that can be used to transfer the user information decreases. Here, the meaning of "more than necessary" is
The maximum number of transmittable bursts decreases by 1 within the minimum burst arrival interval. Therefore, it is sufficient to have at least one opportunity to transfer the flow control information within the minimum burst arrival interval. Nevertheless, in the conventional method, the number of ready cells is 1
Since the reception of the ready pulse is displayed, when the plurality of ready pulses are received within the minimum burst arrival interval, the plurality of ready cells are transmitted unnecessarily.

The flow control information relay transfer method and the relay transfer device of the present invention have been made in view of such a problem. The purpose is to effectively use a transmission line and An object of the present invention is to provide a relay transfer method and a relay transfer device for flow control information capable of minimizing a delay in transferring control information.

[0014]

In order to achieve the above-mentioned object, the present invention relays a predetermined interface with a network having a protocol different from that of the interface so that the user data is transmitted. And flow control information
In the flow control information relay transfer method of transferring as a burst, the measurement step in which the destination node connecting the destination end measures the minimum interval between burst arrivals from a predetermined interface, and the measured burst arrival A counting step of counting the number of ready pulses arriving within the minimum interval, and if the count value of the ready pulses arriving within the minimum burst arrival interval is positive,
The count value is coded and user-decoded via a relay network.
Data is transferred as a data unit different from that of the data. If the ready pulse count value is 0, further wait for the ready pulse arrival, and when it arrives, the ready pulse count value is immediately coded, and the user data is transferred via the relay network. -Processing step of transferring as a data unit different from the data.

Further, according to the present invention, a predetermined interface is relayed by a network of a protocol different from this interface, and user data and flow control information are transferred as different bursts. In the control information relay transfer device, a measuring means for measuring a minimum interval between burst arrivals from a predetermined interface by a destination node connecting the destination ends, and a minimum burst arrival time measured by this measuring means. If the counting means for counting the number of ready pulses arriving within the interval and the count value of the ready pulses arriving within the minimum burst arrival interval are positive, the count value is coded and used by the relay network. -Transfer as a data unit different from the data, and if the ready pulse count value is 0, wait for the ready pulse to arrive further, and immediately after arrival, the ready pulse count value is copied. However, relay networks - click in yu - Zade - data different de -; and a processing means for transferring the data units.

[0016]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a flow chart showing the procedure (steps S1 to S5) of the flow control processing of the destination node according to the first embodiment. In the figure, first, the minimum burst arrival interval (10 microseconds) is measured by the timer as the measuring means, and at the same time, the number of newly received ready pulses is counted by the timer as the counting means to determine the minimum burst arrival. When the number of received ready pulses at the time when the interval elapses is 0 or more, a ready ready cell capable of identifying the number of received ready pulses is immediately transmitted. When the number of received ready pulses is 0, it waits until the ready pulse is received, and at the time of reception, the ready cell that can identify the number of received ready pulses is immediately transmitted. Simultaneously with the transmission, a counter for counting the number of received ready pulses and a timer for measuring the minimum burst arrival interval are initialized and the above processing is repeated.

FIG. 2 shows the flow control process in the destination node. The minimum burst arrival interval is measured from the ready cell transmission, and if there are ready pulses arriving within the minimum burst arrival interval, they are collectively coded and transferred to a single ready cell. In the first section of FIG. 2, since two ready pulses have arrived, a ready cell that can identify that two ready pulses have been received is transmitted. 1 for the second section
The ready cell is transmitted and a ready cell capable of identifying that one ready pulse is received is transmitted. In the third section, the bar
Since the ready pulse has not arrived within the minimum arrival interval of the strike, the arrival of the ready pulse is further waited for, and when it arrives, the ready cell that can identify the reception of one ready pulse is transmitted. In the fourth and fifth sections, since 2 and 1 ready pulses are respectively received, ready cells whose number of received ready pulses can be identified are transmitted.

By using such a method, when a plurality of flow control information are generated within the minimum burst transfer interval, they can be collectively transferred as a single cell in the ATM network. It is possible to describe a plurality of ready pulse receptions in one ready cell, and the number of ready cell transmissions can be set to a maximum of one within the minimum burst arrival interval. As a result, unnecessary ready cell transfer in the relay network can be prevented, and the ratio of the flow control information occupying the transmission path can be reduced. At the same time, if one ready pulse does not reach the destination node within the minimum burst arrival interval, the ready pulse is immediately transmitted when the next ready pulse is received. Therefore, in such a case, even if compared with the conventional method (method that transmits a ready cell each time a ready pulse is received),
There is no delay in transmission timing.

A second embodiment for connecting a terminal having a HIPPI interface via an ATM network will be described below. The connection method is the same as in Fig. 1,
The difference lies in the method of processing flow control information and data in the ATM network. The data processing and flow control processing at the destination node and the source node will be described in order.

First, the ready pulse processing at the destination node will be described. The destination node has a counter (a transfer ready number counter) that counts the number of ready pulses to be transferred to the transmission source end, and a timer that measures the elapsed time from the last ready cell transmission. However, the timer is the minimum
It has a function to measure the minimum interval between strikes (10 microseconds), and then to know that the minimum minimum interval between burst arrivals has elapsed.

FIG. 3 is a flow chart of the flow control information processing of the destination node (steps S10 to S15). First, it waits for the next event (timer expiration or ready pulse reception). And in the case of ready pulse reception,
See if the timer has expired. When it has not expired, 1 is added to the transfer ready number counter. If it has expired, the transfer ready number counter value n at that time is transmitted to the ready cell described in the payload section, and the timer and the transfer ready number counter are initialized.

On the other hand, when the timer expires, the transfer ready number counter value is checked. When the transfer ready number counter value is 0, the next event (ready pulse reception) is waited, and when it is 0 or more, a ready cell is transmitted and the transfer ready number counter and the timer are initialized. Then, it waits for the next event and repeats the same operation.

Next, step S2 in the flow chart of FIG.
The data processing of the destination node will be described based on 0 to S25. Here, the destination node is a buffer capable of accumulating 64 bursts and the number n of ready-to-receive pulses at the destination end.
It has a counter (transmittable burst number counter) that counts the difference between the (receive ready number) and the burst number m (transmit burst number) transmitted by the data destination end.

First, the next event is waited for, and if a ready pulse is received, the presence or absence of a burst is checked. When there is no burst, 1 is added to the transmittable number counter, and when there is a burst, 1 burst is transmitted and 1 is subtracted from the transmittable number counter. On the other hand, if the event is burst reception, the value of the transmittable counter is checked. If it is 0 or more, the burst is transmitted and 1 is subtracted from the transmittable number counter. If the value of the transmittable number counter is 0, it waits for the next event.
The same operation is repeated thereafter.

Next, the data transmission process in the source ATM node will be described with reference to steps S30 to S35 in the flow chart of FIG. Here, the source node is
A counter for counting the number of reception bursts (reception burst number counter, its value Br), a counter for counting the number of transmission bursts (transmission burst number counter, its value Bs), a reception ready number counter (reception) Ready number counter, its value Rr Transmission ready number counter (Transmission ready number counter, its value R
s).

First, the next event is waited for. If the event is the reception of the ready cell, n is added to Rr, and if the burst is received, 1 is added to Br. Next, Rr and Bs are compared, and if Rr is Bs or less, the next event is awaited. R
If r is greater than Bs, check for burst. If there is no burst, wait for the next event, if there is a burst, send the burst, add 1 to Bs, and R
Returning to the process of comparing r and Bs.

The ready pulse processing at the source ATM node will be described below with reference to steps S40 to S of the flowchart of FIG.
44. First, if the event is a burst transmission, add 1 to Bs, and if a ready cell is received, R
Add n to r. Then, m = min [Rr-Rs, buffer size- (Br-Bs)] ready pulses are transmitted. Next, m is added to Rr and the next event is waited for.

By doing so, ready cells can be sent in the destination ATM node without falling below the rate of decrease in the number of ready pulses at the source end, so that the transmission rate at the source end is not reduced. It is possible to reduce the ratio of the transmission lines used for control information transfer and efficiently use the transmission lines.

In this embodiment, as shown in FIG. 7, since the occupancy rate of the flow control information in the relay network can be reduced, the proportion of transmission lines that can be used for user information transfer is increased, and There is an advantage that the rate of effective use of the road can be increased. At the same time, when the ready pulse arrival interval is opened, the ready cell can be transmitted at the same time as the arrival of the ready pulse, so that the delay of the ready pulse transfer due to the flow control information relay processing can be suppressed as short as possible.

The present embodiment is used, for example, when connecting a plurality of end systems which are separated from each other with the HIPPI interface via a protocol different from that of the HIPPI interface, and particularly a large number of users. This is effective when connecting an end system having a HIPPI interface via a public network shared by the users.

[0031]

As described above, according to claim 1 and claim 2,
Since the occupancy rate of the flow control information in the relay network can be reduced, there is an advantage that the ratio of transmission lines that can be used for user information transfer increases and the ratio of effective use of transmission lines can be increased. . At the same time, when the ready pulse arrival interval is opened, the ready cell can be transmitted at the same time as the arrival of the ready pulse, so that the delay of the ready pulse transfer due to the flow control information relay processing can be suppressed as short as possible.

[Brief description of drawings]

FIG. 1 is a flowchart of flow control information processing in a destination node.

FIG. 2 is a diagram showing a flow control process in a destination node.

FIG. 3 is a flowchart showing a flow control process of a destination node.

FIG. 4 is a flowchart showing data processing of a destination node.

FIG. 5 is a flowchart showing a data transmission process in a destination node.

FIG. 6 is a flowchart showing ready pulse processing in a destination node.

FIG. 7 is a diagram showing the operation of the present embodiment.

FIG. 8 is a diagram showing a protocol stack for explaining a conventional method.

FIG. 9 is a diagram for explaining flows of user data and flow control information when a HIPPI interface is relayed by ATM.

FIG. 10 is a diagram showing an operation of a conventional method.

FIG. 11 is a diagram for explaining a flow control process of a destination node in the conventional method.

[Explanation of symbols]

 100 ... Data processing unit, 101 ... Flow control processing unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Daisuke Yamaguchi Inventor Daisuke Yamaguchi 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. A predetermined interface is relayed by a network of a protocol different from this interface,
In the flow control information relay transfer method that transfers the user data and the flow control information as different bursts, the flow control information processing at the destination node is the minimum burst arrival from a predetermined interface. If the counting step of measuring the interval, the counting step of counting the number of ready pulses arriving within the measured minimum burst arrival interval, and the count value of the ready pulses arriving within the minimum burst arrival interval are positive. If the count value of the ready pulse is 0, it is further waited for the arrival of the ready pulse, and immediately after it arrives, the count value is coded and transferred as a data unit different from the user data by the relay network. Flow control information including a processing step of converting the count value of the ready pulse into a code and transferring it as a data unit different from the user data by the relay network. Relay transfer method. 2. A predetermined interface is relayed by a network of a protocol different from this interface,
In a relay transfer device for flow control information that transfers user data and flow control information as different bursts, the destination node connects the destination end and the destination node that connects the destination end has a predetermined interface.
Measuring means for measuring the minimum burst arrival interval from the bus, counting means for counting the number of ready pulses arriving within the minimum burst arrival interval measured by this measuring means, and within the minimum burst arrival interval If the count value of the ready pulse that has reached is positive, the count value is coded and transferred as a data unit different from the user data by the relay network, and if the count value of the ready pulse is 0 In that case, it is further provided with a processing means for further waiting for the arrival of the ready pulse, converting the count value of the ready pulse to the code immediately after arrival, and transferring it as a data unit different from the user data by the relay network. A relay transfer device for flow control information characterized by: