JPS6239933A - Data communication control system - Google Patents

Abstract

PURPOSE:To transfer surely data without giving a large burden on a transmitter by sending transmission data to a specific communication controller connected to the own network system. CONSTITUTION:A communication controller connected among plural local net work systems and relaying communication data between the systems consists of a storage means 10 for storing network constitution information and tran smission/reception means 11a, 11b for transmitting/receiving data with the com munication equipment connected to the network systems, and of a reply sending means 12 for sending a reception confirming reply to reception data from the means 11a, 11b and a relay means 13 for relaying the reception data to other local network system according to the storage information of the means 10. Thus, transmission data is sent to the specific communication controller con nected to the own network system and the specific communication controller sends the reception data to the object local network system according to the network system constituting information stored in the own equipment after the end of reception confirming reply with the communication control equipment.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a data communication control method for a communication system in which at least two local network systems are connected by a specific communication control device and data is transmitted between the local network systems. It is something.

[Summary of the Disclosure] This specification and drawings describe a data communication control method for a communication system in which at least two local network systems are connected by a specific communication control device to transmit data between the local network systems. When transmitting data from a communication device connected to a system to a communication device connected to another local network system, the communication device uses a specific communication device connected to its own network system without having the configuration information of the other network system. The transmission data is sent to the control device, and after the specified communication control device completes the reception confirmation response with the communication control device, it sends the data to the target local network system according to the network system configuration information held in its own device. This disclosure discloses a technology for transmitting data.

[Prior Art] Generally, when a plurality of local network systems are connected to each other via an inter-network communication control device (hereinafter referred to as a gateway) to configure one network system as a whole, when a certain local network system Conventionally, the following method has been used when transmitting a data packet from a connected communication control device (hereinafter referred to as a node) to a node in another local network.

(2) A node broadcasts a transmission packet onto the local network, and each gateway connected to the system receives this packet. Then, the gateway that received this packet should send it to other local networks via its own device (
If the packet should be relayed via the own device, the received packet is sent as is to another local network connected to the own device, and the packet is sent to the target notebook. How to send outgoing packets.

■When each node retains all network configuration information and sends packets to nodes in other local network systems, all relay data including the route to the desired destination node is added to the sent packet. A method in which each gateway relays and transmits packets according to this relay data.

[Problems to be Solved by the Invention] In the above method (■), since the destination address of the transmitted packet (destination address in the data link) is a broadcast address, it is necessary to check whether the transmitted packet has been correctly received by the gateway. cannot,
There is a drawback that it is not possible to confirm transmission and reception using a reception success response (hereinafter referred to as ACK) or a reception failure response (hereinafter referred to as NAK).

In addition, in method (■), since each node must always have information regarding the network configuration, each node must have a storage unit with a large storage capacity, which places a large burden on each node. There was a drawback.

[Means for Solving the Problems] The present invention aims to eliminate the drawbacks of the prior art described above. A communication control device that is connected between local network systems and relays communication data between the systems transmits and receives data between a holding unit 10 that holds network configuration information and a communication device that is connected to the network system. response sending means 12 for sending a reception confirmation response to the received data from the sending/receiving means 11a, flb, respectively, and relaying the received data to other local network systems according to the information held in the holding means 10. relay means 1
Equipped with 3.

[Operation] In such a configuration, when data is transmitted from a communication device connected to one local network system to a communication device connected to another local network system, the communication device has configuration information of the other network system. The specific communication control device sends the transmission data to a specific communication control device connected to its own network system without any error, and after the specified communication control device completes the reception confirmation response with the communication control device, it transmits the network system configuration information held in its own device. Accordingly, the received data is transmitted to the target local network system.

[Example] Hereinafter, an example according to the present invention will be described in detail with reference to the drawings.

FIG. 2 shows an example in which a plurality of local network systems constitute one composite network system via a gateway, according to an embodiment of the present invention.

In FIG. 2, 21 to 27 each represent an independent local network system Lot-LO7, and nodes and gateways are connected to each local network system L01 to LO7. 31 to 36 are each gateway 0
1 to G6. 41 to 52 are each node N1 to Nl2.

In the above configuration, each gateway Gl to G6 (31
- 36) have a routing table for the network configuration, and have a function of determining the transmission route of the packet to be relayed, taking into consideration, for example, the traffic state. Therefore, each of the notebooks N1 to N12' (41 to 52) does not need to store all network configurations within its own device. It is sufficient for each node N1-N22 (41-52) to hold only the system configuration within the local network to which the node itself is connected.

Data communication control between different local network systems in the network system having the above configuration will be explained below.

First, communication control of the nodes N1 to N12 (41 to 52) will be explained with reference to the flowchart of FIG.

In steps St and S2, the note determines whether a packet addressed to the own node is received from the transmission line to which the own device is connected, or whether there is a transmission request from an information processing device, etc. connected to the own node. We are constantly monitoring. For example, when a request for transmission to another notebook, etc. is generated from the information processing device, the process proceeds from step S2 to step S3, and it is checked whether the destination node is a node in the local network to which the own node is connected. . Since the node inputs and retains information about the local network configuration to which its own mate is connected from the gateway etc. as necessary, it is easy to determine whether the destination (destination) note is within its own local network or not. can do.

If the destination node is within the same network (local network), the process advances to step S4, and a transmission data packet is transmitted to the destination node using a known procedure. and step S5
At step S4, it is checked whether a front leg response packet (hereinafter referred to as an ACK packet) has been sent from the destination node, and if an ACK packet is not received, the process returns to step S4 and the previously transmitted transmission data packet is retransmitted. Further, when an ACK packet is received, it means that the transmission data packet has been sent normally, the transmission process is ended, and the process returns to step Sl. If there is still data to be transmitted, the process returns to step S4 and the next data packet is transmitted.

If the destination node to which the data should be sent is not in the same local network in step S3, the data must be sent via the gateway, and in step S6 the data is broadcast simultaneously to all gateways connected to the same local network. Send a transfer request packet to other networks via communication (multicast).

A specific example will be described below in which a data packet is transmitted from the node N1 (41) of the local network system Lot (2nd grade) to the node N10 (50) of the local network system LO6 (26).

In this case, node N1 (41) is connected to the local network system Lot, and all gateways connected to the LOI, namely gateway Gl (
31), G2 (32).

- Sends a transfer request packet to another network to G3 (33) by broadcast communication (broadcast, multicast). This transfer request packet includes transmission request information to the node N10 (50) of the local network LO6.

The gateway that receives the transfer request packet checks whether or not it should use its own gateway to transfer the packet to the node that requested the transmission, and determines whether or not it should use its own device as a relay. If so, it outputs a response to the request sending node to the effect that the packet to be sent should be sent via its own gateway. Therefore, step S6
The node that sent the transfer request packet in step S
At step 7, wait for a response from the gateway.

If there is no response within a certain amount of time, the note you requested to send may not be running on the network system, or
Alternatively, since the information does not exist on the network system, error processing is performed such as notifying the information processing device that outputs the transmission request that transmission is impossible in step S8, and the process returns to step S1.

On the other hand, if there is a response from the gateway, the process advances from step S7 to step S9, and the gateway that has responded, for example, gateway G3 in the above specific example,
(33) returns a response to node Nl0 (50) indicating that it will be sent via this gateway, so the packet addressed to node Nl0 (50) with this gateway G3 (33) as the destination address). Send.

The gateway (G3) that received this packet
(33) Depending on whether or not the reception of the packet from No1s'NI (41) was completed normally without error, l transmits an ACK packet indicating normal completion if the reception is normal, and if it is not normal. sends a negative acknowledgment packet (hereinafter referred to as a NAK packet). Therefore, in the sending note, check the response from the gateway in step SIO and check the ACK
If it is a packet, the process ends and returns to step S1, and N
If it is an AK packet, the process returns to step S9 and the transmission packet is retransmitted.

On the other hand, if there is a received packet addressed to the own node in step S1, the process advances to step S12, and the sent packet is received. Then, in the following step S13, it is checked whether a reception error has occurred, that is, whether or not the reception was successful. If the reception was not successful, a NAK is sent in step 314.
If the packet is successfully received, the reception sends the packet to the sender. and step 3
At 16, the reception waits for an ACK packet for the packet,
If an ACK packet is received, the process ends and step S1
Return to step S if no ACK packet is received.
At step 15, the receptionist retransmits the packet again.

Next, the communication control of the gateway of this embodiment will be explained below with reference to the flowchart of FIG.

In step S21, the gateway sends a packet (
- Monitor the transmission of broadcast messages (including broadcast communication packets). When a packet addressed to the device itself is received, the process proceeds from step S21 to step S22, and it is checked whether the received packet is a relay packet, not a communication packet within the same local network. If the packet is not a relay packet, the process advances to step S23, and it is checked whether the packet is a transfer request to another local network by simultaneous broadcast communication from a node. If it is not a transfer request, it is checked in step S24 whether or not it is a transfer request in the network configuration table held by the device itself, and if it is not a transfer request, processing corresponding to the received packet is executed in step S25. If it is a network configuration table transfer request packet, the process advances to step 326 and the network configuration table is sent out. Then, in step S27, it is checked whether an ACK packet for the transmitted packet has arrived,
If the ACK packet has been received, the process returns to step S21, and if the ACK packet] cannot be received, the process returns to step 326 and the transmission packet is retransmitted.

By sending the above network configuration table transfer request to the gateway, other devices (notebook or gateway) can learn the network configuration at any time.

On the other hand, if a transfer request packet to another network is received in step S23, the process proceeds from step S23 to step S30, where the destination address of the received transfer request packet is analyzed with reference to the network configuration table, and As a result of the analysis, if it is not necessary to transmit by relaying the own device, the process returns from step S31 to step S21,
Do not respond.

If it is determined that the transmission is to be transmitted via the own device, the process advances from step S31 to step S32, and a response packet is sent to the source node of the transfer request packet to the effect that the packet should be transmitted via the own device. And step S3
Step 3 waits for a packet to be transferred from the source node to another local network system. When the transfer packet is received, the process advances to step S34, and it is checked whether the packet has been received normally. If the packet is not received normally, a NAK packet is transmitted in step S35, and a wait is made for the transfer packet to be retransmitted in step S33.

On the other hand, if the packet is successfully received, step S3
Proceed to step 6 and transmit an ACK packet.

Then, in the following step S37, the received packet is transmitted to the gateway of another local network where the destination node specified by the source note analyzed in step S30 exists (relay processing).

” From the double node N1 (41) to the node Nl0 (50)
When transmitting to gateway G3 (33
) sends a response from node N1 to the transmitted packet.
(41) and Goo i-way G3 (33) can confirm reception, and a reliable data link can be established.

Then, gateway G3 (33) sends this transmission packet to the next gateway G5 (35), and gateway G5 (35) receives this transmission packet and connects the destination node to the local network to which its own device is connected. The node Nl0 (50
) and the gateway G5 (35) can perform reliable data communication through a data link, which will be described later.

In the above explanation, in the relay process, the process proceeds from step S32 to step S33, and control is performed to wait only for the transmission packet from the source node. However, the present invention is not limited to this. Returning to the above, control may be performed so that data packets from other nodes can also be monitored at the same time.

On the other hand, in the previous step S22, if the received packet is a relay packet, the process proceeds to step S40, and it is checked whether the relay packet is a packet addressed to a node in the local network to which the device itself is connected. If the packet is not a relayed packet addressed to a node within the own local network but is addressed to a node within another local network, the process proceeds from step S40 to step S37, and the received packet is transmitted to the next gateway.

If the packet is destined for a node in the local network to which the device itself is connected, the process proceeds from step S40 to step 34.1, and the packet is sent to the node. Then, in the following step S42, ACK from the mate
It waits for the packet to be received, and if the ACK packet is confirmed, the process ends and returns to step S21. On the other hand, if the ACK packet is not confirmed, the process returns to step S41 and the relay packet is retransmitted to the destination node again.

For example, from gateway G3 (33) to gateway G5
When a relay packet addressed to node Nl0 (50) is sent to gateway G5 (35), gateway G5 (35) accepts the relay packet because the packet is addressed to a node in network LO6 (26) to which the gateway G5 (35) is connected. Node Nl0(5
0), send an acknowledgment, and establish a reliable data link. Then, if the NoFNIO (50) that received this packet receives the packet normally, the packet is sent to the gateway G5 (35).
and the gateway accepts A for the packet.
Receives the CK packet.

On the other hand, the reception is performed by the gateway G5 (which received the packet)
35) transmits this to gateway G3 (33), and gateway G3 (33) receives the packet from node N10 (50) and transmits the packet to node N1 (41).

From node N1 (41) of -L to node N10 (50)
FIG. 5 shows the processing procedure for transmitting data packets to.

As explained above, according to this embodiment, when data is transmitted from a node on one local network to a node on another local network, the packet includes a broadcast address as the destination address of the data link. A) Since an individual address on the gateway's local network is used instead of a response or multicast address, it is possible to use responses for sending and receiving confirmations such as ACK packets and NAK packets, and these can be used. This allows reliable data linking.

In addition, there is no need for each node to have information on all network configurations, the storage capacity of the node's memory is small, there is no need to perform processes such as updating the network configuration, and communication control is simple and reliable. , allowing efficient data communication.

Furthermore, according to this embodiment, if a node can control communication (procedures) with a gateway within the same local network, it is possible to transmit to nodes in other local networks. Therefore, even when a node moves from one local network to another local network, it is possible to transmit data directly to the other local network with simple communication control. Therefore, configuration mates can be easily moved to other local networks.

"Effects of the Invention" - As explained above, according to the present invention, in a network in which a plurality of local networks are connected via a gateway, data can be transmitted from one local network to another local network. , the data transfer route can be easily determined without imposing a large burden on the transmission equipment, and
A highly reliable data communication control method that can transfer data in a reliable manner can be provided.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of the present invention, FIG. 2 is a network configuration diagram of an embodiment of the present invention, FIG. 3 is a data communication control flowchart of a transmission device constituting the network of this embodiment, and FIG. 4 5 is a data communication control flowchart of the gateway constituting the network of this embodiment, and FIG. 5 is a diagram showing a data communication control procedure with other local networks. In the figure, la, lb...transmission line, 10...holding means,
11a, llb...transmission/reception means, 12...response sending means, 13...relay means, 21-27...local network system, 31-36...gateway, 41-52...node be. Patent Applicant: Canon Co., Ltd. 1 False □;

Claims (2)

[Claims] (1) A data communication control method for a communication system in which at least two local network systems are connected by a specific communication control device to transmit data between the local network systems, and the communication device is connected to one local network system. When transmitting data to a communication device connected to another local network system, the communication device transmits the data to a specific communication control device connected to its own network system without having the configuration information of the other network system. send out,
Data communication characterized in that, after the specific communication control device completes a reception confirmation response with the communication control device, the specific communication control device transmits the received data to a target local network system according to network system configuration information held in the device itself. control method. (2) The data communication control method according to claim 1, wherein the reception confirmation response is a reception success response or a reception failure response, and in the case of a reception failure response, the transmitted data is retransmitted.