JPS59251A - Slot assigning system of loop type network - Google Patents

Abstract

PURPOSE:To reduce a variation of queue depth of a packet and the maximum waiting time, by limiting the number of assigning slots in one node, and preventing a slot in 1 frame from becoming full by a few nodes. CONSTITUTION:A signal of a frame constitution is received by an optical repeater 3 from an incoming link 1, is converted to an electric signal and is sent to an optical repeater control part 5. As a result, the control part 5 controls an optical repeater transmitting part 4 unless a receiving packet is addressed to itself, and transmits the receiving packet to an outgoing link 2. Also, if a slot which arrives at the control part is empty, the control part 5 inquires of a slot assignment control part 8 about the number of continuously assignable packets. In this case, the control part 8 reads contents of a queue counter 7, knows the number of packets stored in a waiting storage device 6, sends its number to an assignment graph 9, informs the number of continuously assignable packets to the control part 5, and the control part 5 reads the packets stored in the device 6 up to the continuously assignable number, and sends them to the outgoing link 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention provides a method for slot allocation in a loop-type network, and more particularly, a method and method for slot allocation in a loop-type network, and more particularly, a method and method for slot allocation in a loop-type network. The present invention relates to a slot allocation method for a loop network for smooth operation of the network by limiting the number of packets that are consecutively allocated to slots of a signal having a frame structure to be transmitted.

Prior Art and Problems FIG. 1 is a diagram schematically showing the configuration of an example of a conventional loop network. In the figure, N1 to N11 are nodes, and adjacent nodes are connected from links 1 to LL+-2 to form a loop. Communication information is allocated as packets to slots of signals in a frame structure, and the loop is connected in one direction (two-way transmission). A loop-shaped network is constructed as shown in Fig. 2. In Fig. 2C2, F indicates one framer, and one frame F is a frame header (FH1 signal bucket). It consists of SG and a plurality of data packets DP, -DPn. The frame header FH, signal bucket) SG, and each data bucket) DPi, DP are each assigned to a fixed time slot.

In FIG. 1C2, for example, the node Nl is the link L! The destination of the data packet input via the node is identified, and if it is addressed to the node, it is taken out from the link (transmission path) L and sent to the node N! The destination terminal TE that is about to be connected to the destination terminal TE (usually there are multiple terminals TE) is sent, and data transmitted from multiple terminals (TE) is temporarily stored in the transmission buffer SR in the form of data packets. , in the signal frame F (Fig. 2) transmitted over the loop network described above, is assigned to an empty time slot assigned to a data packet (to which no data packet has been assigned yet). It will be done.

This allocated data packet is picked up at the destination node and sent to the destination terminal.

In FIG. 1, one node of the loop network, for example, node N, is called a center node and is connected to a terminal T connected to a host computer EC.
It processes the data input from E and sends the results to the corresponding terminal TE.

Conventionally, in the above-mentioned loop network, a method has been adopted in which packets are allocated to slots in a number of empty slots, and an unlimited number of packets are allocated continuously. However, with this conventional method, in some cases, one node may continuously occupy many or all of the slots of one signal frame, and for this reason, packets from other nodes may temporarily occupy the slots. This has the disadvantage that the waiting time for transmission increases.

To explain this situation in more detail, in Figure 1,
When a large number of data packets to be sent to the loop network are stored in the transmission buffer 5Et of each node N, ~N, according to the prior art, the data packets stored in each node are stored in the signal frame F. An unlimited number of consecutive data packet slots will be allocated. Therefore, the slot for data packets of signal frame F becomes full at one node, say N1, and the next node N! The following nodes already have C
The stored data packets for transmission are not allocated at all, in other words, they are not transmitted. Therefore, according to the above-mentioned conventional technology, when traffic increases, one node can send data smoothly, but another node cannot send data, and a long waiting time is required before sending data, which is inconvenient. There was a drawback that caused

When viewed as a whole, the V-stem has the disadvantage that the maximum waiting time for data processing increases.

Object of the Invention The present invention provides a loop-type network in which adjacent nodes are connected with each other to form a loop, communication information is transmitted as packets in 12 slots for frame-structured signals, and the loop is transmitted in one direction. In,
When data packets to be transmitted to the above network are consecutively allocated to multiple slots of a signal with the above frame structure in a loop network, the maximum waiting time of packets waiting at a node, excluding the drawbacks of the above conventional technology. The purpose is to reduce the fluctuations in packet queue length and waiting time.

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

FIG. 3 is a block diagram schematically showing the configuration of one node N in an embodiment of the present invention. In the figure, 1 and 2 are input and output links, respectively, which are configured as optical transmission lines, 3 is an optical repeater receiver, 4 is an optical repeater transmitter, 5 is an optical repeater controller, and 6 is a packet packet. First-in-first, which stores temporarily as a queue.
8 is a slot allocation control unit, and 9 is an allocation graph.

From the input link 1 to the frame structure shown in FIG. 1, a signal having the frame structure shown is received by the optical repeater receiving section 3, converted into an electrical signal, sent to the optical repeater control section 5I, and assigned to the slots forming the frame. Identify the destination code of the packet and
If the packet belongs to the node (self), send the packet to line 10
The data packet is transferred to a receiving buffer (not shown) through the ``(2) destination terminal, and the reception of the required data packet is completed.As a result of the destination code identification, the above received packet is
If the packet is not addressed to the self-node, the optical repeater controller 5 controls the optical repeater transmitter 4 to transmit the received packet to the link 2 and relay the packet.

If no packet is assigned to the slot, the optical repeater control unit 5 identifies this using the same means as described above.

Packets transmitted from the corresponding node N are sent via a line 11 from a terminal (not shown) to the waiting storage device 6 in the order in which they are input (
= Can be stored.

The queue counter 7 cumulatively adds up the number of packets input to the waiting storage device 6 from the line 11, and cumulatively subtracts the number of packets sent out from the waiting storage device 6 via the optical repeater control section 5. , always (2) The number of packets stored in the waiting storage device 6 (2) is determined by the optical repeater control unit 55I. The number is set in the slot allocation control section 8.

The slot allocation control unit 8 reads the contents of the queue counter 7 and learns the number of packets currently stored in the waiting storage device 8 at that time. The slot allocation control unit 8 sends this number of packets to the allocation graph 9 for reference, and notifies the optical repeater control unit 5 of the packets and number that can be consecutively allocated. The optical repeater control unit 5 reads the stored packets sequentially (2) up to the number of consecutively allocable packets from the waiting storage device 6, allocates them to slots, and controls the optical repeater transmitting unit 4 to output them. Link 2C: Send.

Figure 4 shows the necessary points when determining the number of packets that can be allocated consecutively.
This shows an example of a necessary layout graph.

In FIG. 4, the abscissa indicates the number of packets stored in the waiting storage device 6, and the ordinate indicates the number of packets indicated on the abscissa (with the drawbacks mentioned above). The allocation graph 9 in FIG. ), and the fourth
It can be easily configured based on the graph shown in the figure.

In the example of FIG. 4, waiting state C: When the number of packets (stored in waiting storage device B) is 1, 2, 6, 4, and 5 or more, the number of packets that can be consecutively allocated is as follows:
1.2, 5, 4 respectively. and 5 are obtained. That is, if the number of packets in the waiting state exceeds five, the number of packets that can be consecutively allocated is limited to five, no matter how many packets there are.

In this way, if there are a large number of packets in the waiting state according to the allocation graph, the number of packets that can be consecutively allocated is limited to a certain value or less.

When using the allocation graph shown in FIG. Since the number of packets is specified as 5, at this node, only up to 5 slots are allocated to one frame of the signal, and other empty slots are used for the next one. This prevents the slot from becoming full at one or a small number of nodes, and allows each node to allocate a small number of packets.

The present invention has been described above with respect to one embodiment, but the present invention also includes the following:
The present invention is not limited to this embodiment, and various modifications can be made within the technical scope.

FIG. 4 merely shows an example of the layout graph, and its contents can be modified in various ways depending on the configuration of the loop network and traffic conditions (including the number of slots in one frame, etc.).

Note that in the embodiment of FIG. By creating an allocation graph that sets packets to be sent based on this waiting time, it becomes possible to perform control so that packets that have reached the set maximum waiting time (C) are always sent.

Furthermore, it goes without saying that the link is not limited to an optical transmission line, but may also be an electrical signal transmission line.

Effects of the Invention Since the present invention is configured as described above, adjacent nodes are connected by links to form a loop, communication information is allocated as packets to slots of signals in a frame structure, and transmitted in one direction through the loop. In a loop network configured to do this, when data packets to be transmitted to the network are successively allocated to multiple slots of a frame-format signal of the loop network,
According to the present invention, the allocation in one node limits the number of slots, and C prevents the slots in one frame of a signal from becoming full in less than two nodes;
This has the effect of reducing changes in the packet queue length (ie, the number of packets that can be simultaneously stored in the queue storage device) and the maximum waiting time, especially during transient conditions.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the configuration of an example of a conventional loop network configured by conventional nodes, FIG. 2 is a diagram showing the format of signals transmitted on the loop network, and FIG. 4 is a diagram showing an example of a node configuration according to the present invention, and FIG. 4 is a diagram showing an example of the layout graph in FIG. 3. N, N1 to N1... Node, L, ~L11... Link, SB... Packet transmission buffer, 1... Incoming link, 2... Outgoing link, 3... Optical repeater receiving section , 4・
... Optical repeater transmitting section, 5... Optical repeater control section, 6...
- Waiting/memory device, 7... Queue counter, 8...
・Slot allocation control unit, 9...Allocation graph, 10,
11...Line patent originator Fujitsu Ltd. agent Patent attorney Gobe Tamamushi (3 others) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a loop type network in which adjacent nodes are connected by links to form a loop, communication information is transmitted as packets in the form of frame-structured signal slots), and the loop is transmitted in one direction.
It includes a waiting storage device for temporarily storing packets to be transmitted from the node to the loop network, a waiting counter for counting the contents of the storage device, a slot allocation control unit, and an allocation graph. , the slot allocation control unit refers to the allocation graph from the contents of the waiting kakunta, and as a result (2) reads from the waiting storage device and continuously allocates slots to limit the number of 5 packets. A slot allocation method for loop-type networks featuring the following.