JPH0787465B2 - Ring transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention uses one of dual ring transmission lines that transmit in opposite directions as a data transmission line and the other as a queue transmission line of a transmission request, and uses the two rings for both rings. The present invention relates to a ring transmission method for performing fixed-length packet transmission between a plurality of connected node devices.

[Conventional technology]

As a fixed-length packet transmission network configuration using a conventional dual bus transmission line, QPSX [RMNewman, JLHul] shown in FIG. 3 is used.
let, “Distributed Queueing: A Fast and Efficient Pa
cket Access Protocol for QPSX ", Proceedings of the
Eighth International Conference on Computer Commun
ication (ICCC'86), pp294-299, Munich, FRGSept.1
986]. In addition, this QPSX has been approved by TELECOM AUSTRALIA as a DQDB [Docume
nt: IEEE802.6 / 87-01 March 25, 1987].

Fig. 4 shows the configuration of this QPSX node device. The most upstream node of the data transmission line L1 has a function of generating a fixed length frame, and absorbs all signals at the most downstream ends of the data transmission line L1 and the queue transmission line L2. Furthermore, each node device has terminals (tap: D _i , D ₀ , Q _i , Q ₀ ) for branching / coupling passively to the data transmission line L1 and the queue transmission line L2, and terminals on the terminal side for transmitting / receiving data ( There are S, R). The communication procedure of the node device is shown below.

Packet transmission The node device to which the data signal to be transmitted is input to the transmission input S checks the up / down counter 406 and its value is “0”, and the packet reception from the data transmission line L1 via the branch terminal D _i is performed. Upon receiving an empty packet in the circuit 401, through a coupling terminal D ₀ with the destination node number to transmit data in packet transmission circuit 402 transmits the data transmission line L1.

At that time, the cue signal for the transmission request is sent to the cue transmission circuit 40.
The value of the up / down counter 406 is set (copied) to the down counter 405 at the same time as being sent from the coupling terminal Q ₀ to the queue transmission path (direction opposite to the data transmission direction) L2 via 3. After that, every time an empty packet is received from the data transmission line L1, the down counter 405 is checked and its value is “0”.
If, sent to the data transmission path L1 via the coupling terminal D ₀ with the destination node number.

The meaning of sending the queue signal for the transmission request to the queue transmission line L2 is to instruct all the node devices upstream of the data transmission line L1 from the node device to bypass one empty packet. is there.

The operation of the up / down counter 406 and the down counter 405 is set to "0" (reset) at the time of initialization of this network. Up / down counter 406 value down counter 4
The timing of copying to 05 is the time when the data signal to be transmitted is input to the transmission input S. When the queue receiving circuit 404 detects a queue signal via the branch terminal Q _i of the queue transmission line L2, “1” is added to the up / down counter 406. On the other hand, when an empty packet is detected via the branch terminal D _i of the data transmission line L1, “1” is subtracted from both counters 405 and 406 (that is, not less than “0”). By this operation, it is indicated that there is transmission request data downstream by the value indicated by the up / down counter 406. Further, the empty packet corresponding to the value set in the down counter 405 is sent off for the downstream node transmission, and the data transmission can be performed using the empty packet that comes after that.

Packet reception circuit Packet reception circuit via branch terminal D _i of data transmission line L1
When a packet addressed to its own node is received at 401, the packet is output to the reception output terminal R.

[Problems to be Solved by the Invention]

The throughput characteristics of the above conventional QPSX node device configuration are
Despite the communication between distributed node devices, M / D /
The above QPS shows that it shows good characteristics close to a single queue of 1.
Reported in X. However, since the passive node is used, the packet cannot be erased on the receiving node device side, so that the transmission line cannot be reused downstream of the node device. Further, in the case of applying to the bidirectional bus, it is necessary to add a process of selecting a direction to which the destination node device is located downstream. A ring transmission line can be considered as a method of avoiding this direction selection process.
Since SX uses the method of absorbing the transmitted packet signal and queue signal at the transmission line end, it was not applicable when the ring was used because the transmission line end was lost.

An object of the present invention is that in the above conventional method, the transmission line cannot be reused in the downstream of the receiving node device of QPSX, and that the destination node device requires a process of direction selection which side is downstream, An object of the present invention is to provide a ring transmission method that solves the problems that cannot be applied to ring networks.

[Means for Solving the Problems]

According to the present invention, one of dual ring transmission lines that transmit in opposite directions is used as a data transmission line and the other is used as a transmission queue for transmission requests, and a plurality of node devices are connected to both rings and fixed between the node devices. In a ring transmission system for transmitting long packets, the node device has means for erasing a received packet addressed to its own node, and a number of queues corresponding to empty packets generated by erasing the received packet addressed to the own node. A means for erasing the signal and a means for adding the reset orbit monitor flag to the transmission of the cue signal are provided, and the specific node device (monitor node) on the ring transmission line is
It is characterized in that means is provided for erasing the cue signal in which the revolution monitor flag is set and for setting and relaying the cue signal in which the revolution monitor flag is reset.

[Work]

According to the present invention, the transmission path access in the node device is made active so that the receiving node device side can delete the packet, and further, in order to avoid the circulation of the queue signal, the queue signal is deleted in the node device which generated the empty packet. At the same time, the monitor node device is configured to delete the reception queue signal in which the circulation monitor flag is set. As a result, it can be applied to a ring network, and it becomes unnecessary to perform a direction selection process as to which side the destination node device is located downstream.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of the ring transmission system of the present invention. In the present invention, in the ring network shown in FIG. 1, one of the dual ring transmission lines that transmit in opposite directions is used as the data transmission line L1 and the other is used as the queue transmission line L2 of the transmission request and connected to both rings. Fixed-length packet transmission is performed between a plurality of node devices 1 to N.

FIG. 2 shows a block diagram of an embodiment of a node device connected to both rings of the data transmission line L1 and the queue transmission line L2 of FIG. In FIG. 2, 100 is a packet transmission / reception control circuit, and 110 is a clock generation circuit. Reference numeral 101 is a packet synchronization circuit, 102 is a variable delay circuit for adjusting the ring circulation time, 103 is a multiple circulation packet removal circuit, 104 is a branch switch, and 105 is an insertion switch. Similarly, 106 is a packet synchronization circuit, 107 is a variable delay circuit for adjusting the ring circulation time, 108 is a multiple circulation packet removal circuit, and 109 is a queue insertion circuit. 111 is a self-node address register, 112 is a packet header detection circuit, and 113 is a queue detection circuit. Reference numeral 114 is a reception buffer, and 115 is a transmission buffer.

The packet transmission / reception control circuit 100 includes a transmission request reception number counter (RC) from another node, a transmission waiting display counter (QC) in its own node device, a transmission waiting counter (WC) in its own node, and a queue signal transmission waiting number display. It has a counter (IC), a queue signal removal wait number display counter (DC), and a timeout counter (TOC). The ring round trip time adjustment variable delay circuits 102 and 107 and the multiple round packet removal circuits 103 and 108 are necessary only for the monitor node device.

FIG. 5 shows a configuration example of a packet signal on the data transmission line, a queue signal on the queue transmission line, and a packet signal sharing them.

FIG. 6 shows a control flowchart for explaining the operation in the node device. FIG. 6A shows control of node initialization, ring initialization, and multiple round packet discard control. This processing is performed by the packet transmission / reception control circuit 100 and the multiple round packet transmission / reception control circuits 103 and 108. FIG. 6B shows control of packet transmission / reception / relay and empty packet transmission. This processing is performed by the packet transmission / reception control circuit 10.
Done at 0. FIG. 6C shows control of queue management, and this processing is also performed by the packet transmission / reception control circuit 100, but transmission / reception is performed on the queue transmission path. FIG. 6D shows control of transmission data management, which is also performed by the packet transmission / reception control circuit 100, but transmission / reception is performed on the data transmission path. In FIG. 6, the part surrounded by the broken line shows the processing for the transmission path. The meaning of each symbol is as follows.

TOC: Timeout counter LED: Data transmission line ring status display (normal / abnormal: 0/1) LEQ: Queue transmission line ring status display (normal / abnormal: 0/1) QC: Transmission waiting display counter in the local node WC: Transmission waiting counter in the local node RC: Counter for receiving transmission requests from other nodes (downstream node) DC: Counter for displaying QF removal wait count counter IC: Counter for displaying QF transmission wait QF: Queue flag (Yes / No: 1/0 ) MF: Monitor flag for detecting multiple roundabout cells *: MF = 1 at the monitor node DA: Destination node address F / E: Packet in use / empty MA: Own node address The following describes the operation in each state in the node device. .

(1) Packet transmission Empty packet reception & packet transmission (Fig. 6 (d),
(B)) The node device having the transmission data input from the transmission data input S and accumulated in the transmission buffer 115 sets the transmission waiting display counter QC (QC = 1), and the transmission request reception number counter RC
The value of is copied to the transmission wait counter WC in the local node. And check the WC. If CW = 0, when an empty packet E is detected from the data transmission line input D _i via the packet header detection circuit 112, the packet transmission / reception control circuit 10
0 outputs an insertion instruction to the insertion switch 105, replaces the empty packet with a transmission data packet with a destination node indication in the transmission buffer 115 to make it a packet in-use F, and further resets the orbit monitor flag MF to transmit data. It is transmitted from the road output D ₀ , and the transmission waiting display counter QC is reset (QC = 0).

However, in the data transmission operation, queue transmission is required when the value of the transmission request reception number counter RC is copied to the transmission waiting counter WC in the own node.

Queue transmission (FIGS. 6 (d) and 6 (e)) Each time the transmission wait display counter QC becomes 1, the queue signal transmission wait number display counter IC is incremented by 1. Queue transmission line output Q ₀
When the queue detection circuit 113 does not receive the queue signal QF at the timing QF = 0 and the queue signal transmission wait number display counter IC is positive, the orbit monitor flag is transmitted.
The cue signal QF = 1 that resets the MF is inserted into the cue insertion circuit 10
Send to queue transmission line output Q ₀ via 9. And
When the queue signal transmission waiting number display counter IC is positive, it is decremented by 1, and the transmission data waits for transmission.

(2) Cue signal deletion Packet reception & empty packet generation & cue signal removal (6th
(B), (c)) When a packet DA = MA addressed to its own node is received from the data transmission line input D _i via the packet header detection circuit 112, the packet transmission / reception control circuit 100 outputs a branch instruction to the branch switch 104. Then, the received packet is accumulated in the reception buffer 114,
Output from the received data output R. If QC = 1 to WC = 0, the packet transmission / reception control circuit 100 outputs an insertion instruction to the insertion switch 105, resets the empty packet display F and the circulation monitor flag MF (MF = 0), and outputs the data transmission path. Send an empty packet from D ₀ . Then, the cue signal removal waiting number display counter DC is incremented by 1.

When the queue signal QF = 1 is received from the queue transmission line input Q _i via the queue detection circuit 113, the queue signal removal is performed by checking the queue signal removal waiting number display counter DC, and if DC = 0, the transmission request reception counter RC Is increased by 1. On the other hand, when DC is positive, the cue signal QF = 0 in which the circulation monitor flag MF is reset (MF = 0) is transmitted to the cue transmission path output Q ₀ via the cue insertion circuit 109, and the cue signal removal waiting number is displayed. Decrement the counter DC by 1.

(3) Simultaneous data transmission / reception Packet reception & packet transmission (FIG. 6 (b)) When a packet of DA = MA addressed to the own node is received from the data transmission line input D _i via the packet header detection circuit 112, packet transmission / reception control The circuit 100 outputs a branch instruction to the branch switch 104, accumulates the received packet in the reception buffer 114,
Output from the received data output R. If QC = 1 and WC = 0, the packet transmission / reception control circuit 100 outputs an insertion instruction to the insertion switch 105 and replaces the transmission data packet with the destination node indication accumulated in the transmission buffer 115 with the packet in use F Then, the circulation monitor flag MF is reset, the data transmission path output D _{0 is} transmitted, and the transmission waiting display counter QC is reset (QC = 0).

Packet relay (FIG. 6 (b)) When a packet of DA ≠ MA addressed to another node is received from the data transmission line input D _i via the packet header detection circuit 112, the packet transmission / reception control circuit 100 outputs nothing. The received packet is relayed to the data transmission line output D ₀ .

(4) Management of transmission request reception counter similar to QPSX Management of transmission request reception counter (FIGS. 6 (b) and (c)) In the node device, the queue signal removal waiting count display counter DC is zero (DC = 0). In this case, when the queue signal QF from the queue transmission path input Q _i is relayed, the transmission request reception number counter RC is incremented by 1, as in QPSX.

When the node device relays the empty packet E from the data transmission line input D _i , if the transmission waiting counter WC in its own node is not zero (WC ≠ 0), it subtracts one. Further, if WC = 0 and the transmission request reception number counter RC is not 0, 1 is subtracted.

(5) Initial setting of the ring and processing at the time of abnormality One of the node devices connected to the ring is used as the operation monitor node device, and the ring circulation time is set so that an integer multiple number of packets can exist in the data transmission path in the monitor node device. Variable delay circuits 102 and 107 for adjusting are used. Further, a clock generation circuit 110 for supplying to the ring in the monitor node device.
In addition, generators 103 and 108 that generate an empty packet for the ring round when the packet cannot be received are used.

Ring node initialization (Fig. 6 (a)) In all node devices, a timeout counter TOC that detects when a packet format is not received for a certain period of time (abnormal ring state), and when the TOC times out, all Reset the internal counters (QC, RC, WC, DC, IC) of to initialize the node equipment.

Elimination of multi-turn packet / queue signal (Fig. 6 (a),
(B)) The packet and the queue signal QF have a loop monitor flag MF that is set when the packet is relayed by the operation monitor node device.
When the packet in which is set is received, the packet is replaced with an empty packet to be relayed, and the queue signal QF for receiving the queue signal QF in which the circulation monitor flag MF is set is removed and relayed. As a result, it is possible to remove the multi-turn packet data and the queue signal QF from the ring, which are caused by an error in the node or the transmission line or when the ring turn time is small.

By using the procedure described above, it becomes possible to reuse the transmission path downstream of the receiving node device in QPSX. Therefore, the ring transmission line has higher throughput.

As shown in FIG. 5, a queue signal QF area of the other party's ring is provided at the beginning of the packet, and each node group is processed by the node device (in FIG. 1, two node devices are assembled). Then, one of them is rotated 180 degrees and connected to be replaced with one node. (However, the packet synchronization circuit only needs to be on one side), and both rings can be used as a data transmission path. By this,
It is possible to obtain double the throughput as compared with the case where only one loop is used for the data transmission path.

Further, by cutting two transmission lines between adjacent two node devices and connecting them in a direction in which they are folded back, it is possible to operate as a single ring. However, since the number of transmission lines is halved as compared with the case of the double ring, the throughput is also halved or less. To suppress this decrease, it is necessary to select a transmission direction that does not include the folded end.

〔The invention's effect〕

As described above, according to the ring transmission method of the present invention, it becomes possible to prevent the conventional QPSX from reusing the transmission path downstream of the receiving node device, and the communication between the node devices becomes uniform. In the case of, there is an advantage that the throughput of the ring transmission line is approximately doubled. Further, the cue signal cancellation according to the present invention can be similarly applied by canceling from the higher cue signal in the QPSX that performs priority data transmission. Further, the configuration applicable to the ring network has an advantage that it is not necessary to perform the process of selecting the direction on which side the destination node device is located downstream.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a ring transmission system of the present invention, FIG. 2 is a configuration diagram of an embodiment of a node device in FIG. 1, and FIG. 3 is a diagram showing a conventional QPSX network configuration. Figure 4 shows QP
FIG. 5 is a configuration diagram of the SX node device, FIG. 5 is a diagram showing a configuration example of a packet signal and a queue signal used in the present invention, and FIG. 6 is a control flow chart for explaining the operation of the node device of FIG. 1, N ... Node device, L1 ... Data transmission line, L2 ... Queue transmission line, 100 ... Packet transmission / reception control circuit, 101,106 ...
... Packet synchronization circuit, 102, 107 ... Variable delay circuit for adjusting ring circulation time, 103, 108 ... Multiple circulation packet removal circuit, 104 ... Branch switch, 105 ... Insertion switch, 109
... queue insertion circuit, 110 ... clock generation circuit, 111 ...
… Self-node address register, 112 …… Packet header detection circuit, 113 …… Queue detection circuit, 114 …… Reception buffer,
115 …… Send buffer.

Claims (1)

[Claims] 1. A dual ring transmission path for transmitting data in opposite directions is used as a data transmission path, and the other is used as a queue transmission path for a transmission request, and a plurality of node devices are connected to both rings, and between the node devices. In the ring transmission method in which fixed length packet transmission is performed, each node device has a packet transmission waiting counter that counts up when a queue signal passes and counts down when an empty packet passes, and transmits a packet when the transmission waiting counter is zero. A ring transmission method in which a queue signal is transmitted when there is a packet transmission request, and an empty packet is transmitted when the transmission waiting counter is 1 or more and there is no request packet. A means for erasing the received packet and a number of keys corresponding to the empty packets generated by erasing the received packet destined for the own node. A means for erasing the queue signal and means for adding a reset round trip monitor flag to the transmission of the cue signal are provided, and the cue signal for which the round trip monitor flag is set is deleted for the specific node device on the ring transmission line. A ring transmission method characterized in that means for setting and relaying the cue signal in which the monitor flag is reset is provided.