JPS61131940A - Packet transfer system - Google Patents

Abstract

PURPOSE:To allow the titled system to cope flexibly with variance in traffic by allowing a transmission station to add the propriety of path change to the final packet of each packet string subjected to blocking transmitted from a terminal device and to transmit the result to discriminate the presence of a response to a transmission confirming bit. CONSTITUTION:A node A at the side of a terminal device 1 of a packet transmission system is used as a transmission station, data is given to a node E at the reception side via nodes B-D as relay stations and the data is transferred from the node E to a terminal device 2. When a reception process 11 of a node 10 receives a packet from an adjacent node, the reception is informed to a path selection process 14, which informs the reception to a path change propriety control process 13. The process 13 adds path change propriety information to the reception packet discriminated to be path change enable and gives the result to the process 14. When the relay information of a logical bus to which the reception packet belongs is registered on a relay table 15, the process 14 extracts the information and informs an output path to a transmission process 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a data transfer system in a data communication network, and particularly to a packet transfer system.

[Technical background of the invention and its problems]

Packet transfer in conventional networks has been performed based on either a datagram method in which a relay path is independently selected for each packet, or a fixed relay path method in which a relay path is fixed for each logical path.

While the datagram method can flexibly respond to traffic fluctuations by selecting the optimal route for each packet, generally the order in which packets arrive at the receiving station is not necessarily based on the originating class, but rather on buffers for sequence control, waiting time, etc. In the fixed relay route method, the order in which packets arrive at the receiving station does not change, so order control is not necessary, but on the other hand, it is not possible to respond flexibly to traffic fluctuations. was there.

[Purpose of the invention]

The present invention eliminates each of the above drawbacks, combines the advantages of both methods, eliminates the need for buffers for order control, waiting time, and processing time, and provides a packet transfer method that can flexibly respond to traffic fluctuations. The purpose is to provide.

[Summary of the invention]

The present invention allows a transmitting station to determine whether or not to change a route by attaching the final part of each blocked packet string sent from a terminal to a bit, and determining whether or not there is a response to a delivery confirmation bit. This objective has been achieved by introducing a mechanism that adds the result to the packet as route change permission information and notifies the relay station.

[Embodiments of the invention]

FIG. 1 shows an example of a packet switching network to which an embodiment of the present invention is applied, where A to E are nodes in the network, and when transferring a packet from terminal 1 to terminal 2, node A is a transmitting station, Node E receiving station and nodes BD become relay stations.

FIG. 2 is a block diagram showing the configuration of each node shown in FIG. 1. In the figure, (11) is a receiving process that receives packets from a terminal connected to the own node or an adjacent node, and (12) is a transmitting process that sends out the packets. (13) is a route change control process that determines whether or not a different route can be selected from the next packet on the same logical bus for a packet whose transmission station is this node (lO), and (14) is a process for controlling whether or not a packet is received. (15) is a relay table that stores the routing result of route selection, and (16) is an optimal route selection process that determines the most appropriate output route at present from the destination information of the received packet. route decision process.

Next, the operations of the transmitting station (node A) and each relay station (nodes BD) when transmitting a packet from terminal 1 to terminal 2 in the configuration example of FIG. 1 will be explained.

When node A receives the blocked packet string from terminal 1, it sequentially sends the received blocks to the destination over the same route starting from the first packet (which usually has route change permission information). Each of these packets contains information that identifies a logical path, and the final packet of the block has a delivery confirmation bit set. After transmitting one block, it waits for a response packet from the receiving station6.
Next, upon the arrival of the response packet, node A determines that it is possible to select another route on the same logical path from the next packet, and attaches route change permission information to the first packet. Send blocks of packets sequentially.

The first packet having the route change permission information arrives at the receiving station while the optimum route is selected at each relay station.

Each relay station records routing information regarding the output route selection at that time in a relay table within the relay station. Then, after confirming this record, the same output route is selected for the annoying packet. After sending out the packet with the final delivery confirmation bit of the block, the routing information in the relay table is deleted and preparation is made for the next head packet.

Next, the operation shown in FIG. 2 will be explained. The reception process (11) sends a strategy selection process (14) when a packet is received from an adjacent node, and a route change permission control process (13) when a packet is received from a terminal connected to its own node.
Notify the packet arrival. In the route change permission control process (13), route change permission information is added to the received packet determined to be route changeable, and the packet is passed to the route selection process (14). Route selection process (1
In 4), if relay information regarding the logical path to which the received packet belongs is registered in the relay table (15), the output route is determined from that information and notified to the transmission process (12). If the relay information is not registered in the relay table, the optimum route determination process (16) is requested to select the optimum route, and the result is notified to the transmission process (12). The selection result is also registered in the relay table (15). When the received packet is the final packet of the block, the corresponding relay information is sent to the relay table (15) along with the sending of that packet.
Delete from. In the transmission process (12), the received packet is sent out to the output route specified in the strategy selection process (14).

〔Effect of the invention〕

The present invention is as described above, and has the following features: i) Compared to the datagram method, flexibility in response to traffic fluctuations is not impaired, and order control on the receiving side is not required;
It is possible to shorten the delay time within the network and reduce the required reception buffer size. ii) Also, compared to the fixed relay route system, it is possible to respond more flexibly to traffic fluctuations. This effect can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a bucket network to which an embodiment of the present invention is applied, and FIG. 2 is a block diagram showing the configuration of each node shown in FIG. 1. A: Transmitting station, E: Receiving station, B, C, D: Relay station.

Claims (1)

[Claims] The transmitting station sequentially sends the blocked packet string received from the terminal block by block, starting from the first packet, along the same route.
In addition, the last packet of each block is sent with the delivery confirmation bit set, and after receiving the delivery confirmation from the receiving station, the sending station sends the next block with route change permission information, allowing the sending station to change the route. A packet transfer method characterized by controlling availability.