JPH08186601A - Data transfer method for communication equipment - Google Patents

Abstract

PURPOSE: To realize optimum data transfer corresponding to the property of transfer data and the situation of an opposite communication equipment and the like. CONSTITUTION: At the time of establishing connection between a pair of the communication equipments, a connection parameter deciding a transfer condition is inquired to the opposite communication equipment by a parameter setting request and a self connection parameter is set based on a parameter setting request response transmitted from the opposite communication equipment. Data is transferred with the opposite communication equipment through a network based on the setting result. For enlarging a transfer rate, for example, the maximum value of packet size in the connection parameter is set to be large as much as possible and a transfer interval to be small as much as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transferring data between communication devices connected to a network, and more particularly to setting connection parameters for defining conditions for data transfer.

[0002]

2. Description of the Related Art As a system for transferring data between communication devices connected to a network, there is, for example, a client / server printer system, and communication devices such as client devices, front-end servers, and printer devices are available. Packet data is being transferred. The transfer of such packet data is performed by establishing a connection according to the protocol between the communication devices, and the transfer conditions such as the data transfer rate between the communication devices are set as fixed values for each communication device. It is defined by connection parameters related to maximum size, window size, transfer interval, minimum retransmission interval, maximum retransmission interval, maximum number of retransmissions, checksum, probe, etc.

Here, in the field of data transfer, there is a problem to improve the capacity and reliability of data transfer. To realize this, communication devices are connected by a plurality of lines,
A multi-link method has been conventionally known in which a required throughput is obtained by a plurality of these lines, or when a certain line has a failure, data transfer is continued on the remaining lines. Also,
In the multilink system, according to the invention described in Japanese Patent Laid-Open No. 3-45051, the data amount (window size) that can be continuously transmitted by the transmitting side device is set for each line according to the buffer capacity of the receiving side device. A method has been proposed in which the data transfer capability and reliability are improved by setting the data at any time. In other words, in this method, the amount of data processed for each line is monitored, and the window size is set small for lines with a low amount of data processing and relatively large for other normal lines. Set
The data processing capacity of the entire system is improved.

[0004]

Here, for example, when transferring image data or the like having a very large data size, if the transfer rate can be increased as much as possible, the efficiency of data transfer can be improved. Further, in a front-end server that manages a plurality of printers, if the connection parameters suitable for each printer can be set, the efficiency of data transfer can be improved. However, in the conventional system in which the connection parameter is set to the communication device as a fixed value, the data transfer between the communication devices is performed at a constant rate, so that the efficiency is improved according to the property of the transfer data such as the data size. However, it has not been possible to realize data transfer that is finely adapted to the communication device of the other party.

In the special case where the multi-link system is adopted, the window size has been conventionally changed as described above. In this conventional example, however, it is not the nature of the transfer data but the line. The control is performed in accordance with the data processing amount of, and only a very small part of the connection parameters (window size) is changed by this control. Therefore, it is not possible to effectively change the transfer rate, and it is possible to solve the problems that the efficiency is improved according to the property of the transfer data and the data transfer suitable for the processing capability of the communication device of the other party is not realized. Was not acceptable.

The present invention has been made in view of the above conventional circumstances, and provides a data transfer method for a communication device capable of realizing optimum data transfer according to the nature of transfer data, the communication capability of the communication device of the other party, and the like. With the goal.

[0007]

In order to achieve the above object, a data transfer method of a communication device according to the present invention includes a communication device (1 to 1) connected to a network (6: reference numeral in FIG. 1, omitted below). In the data transfer method of 5), when the connection is established, the communication device (3) of the other party is inquired about the connection parameter that determines the transfer condition, and based on the result of the inquiry, the communication device (3) of the other party of the self (2) It is characterized in that connection parameters are set and data is transferred via the communication device (3) of the other party and the network (6) based on the setting result.

[0008]

According to the present invention, when a connection is established between a pair of communication devices connected to a network, one communication device inquires of the communication device of the other party about the connection parameter, and the connection parameter of the communication device of the other party is used as the inquiry result. obtain. One communication device is
Based on the connection parameter of the other party, its own connection parameter is set so as to obtain an optimum transfer rate, and data is transferred with the communication device of the other party based on the set connection parameter.

In setting the above-mentioned connection parameters, the transfer rate can be maximized by setting, for example, the packet size or window size among the connection parameters to the maximum value or the transfer interval to the minimum value. The value of the connection parameter is an optimum value within the range that can be set for both communication devices. In addition, it is preferable to notify the communication device of the other party of its own connection parameter, and the optimum parameter within the range that can be adopted by both communication devices is set in both communication devices, and data transfer is performed based on the connection parameter. .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A data transfer method of a communication device according to an embodiment of the present invention will be described. First, an example of a network configuration for implementing the present invention will be described with reference to FIG. A client device 1 as a communication device, a front-end server 2 and printers 3-5 are connected via a network 6, and between the client device 1 and the front-end server 2 and between the front-end server 2 and the printers 3-5. Data transfer by packets is performed via the network 6 between them.

Regarding the data transfer according to the present invention, the client device 1, the front end server 2 and the printers 3 to 5 have the same functions and have a common configuration as shown in FIG. . That is, the communication devices 1 to
5 has a network protocol control unit 11,
Controls packet transfer according to the protocol. The protocol control unit 11 is provided with an upper layer protocol control unit 12 corresponding to an upper layer of the protocol and a packet switching control unit 13 corresponding to a lower layer of the protocol, and the upper layer protocol control unit 12 performs various operations. Interface processing with the application 14 and compression processing accompanying data transfer are performed, and the packet switching control unit 13 performs interface processing with the network 6 and packet switching processing based on connection parameters.

Further, the packet exchange control unit 13 is provided with a parameter exchange determination notifying unit 15 and a parameter setting unit 16. The parameter exchange determination notifying unit 15 and the parameter setting unit 16 allow the packet switching control unit 1 to operate.
In step 3, a predetermined process is performed on the packet data to be transmitted or received. That is, the parameter exchange determination notification unit 15
Performs processing for notifying a connection parameter exchange request or connection parameter setting request sent to the other party of communication, and processing for determining a connection parameter exchange request response or connection parameter setting request response sent from the other party. . Further, the parameter setting unit 16 performs a process of setting the connection parameter of the own device based on the connection parameter sent from the other party.

In this embodiment, as an example of the connection-oriented protocol, OSI (Open Systems Interconne
XNS (Xerox Network Systems) SPP (Sequenc) corresponding to the transport layer and network layer of
An application example of the ed Packet Protocol) will be described. SPP assigns a sequence number to the packet passed from the upper layer of the protocol stack at the time of transmission,
Sequence control, duplication control, flow control, etc. are performed, and the packet used for communication has a format as shown in FIG.

The packet includes a field 21 related to connection control, a field 22 related to an address including connection identifiers of a source and a destination, a sequence number,
A field 23 relating to communication control including an acknowledge number and an allocation number and a field 24 for storing data are included. As shown in detail in the figure, the connection control field 21 includes a data stream type 31, a system packet 32, a send acknowledge 33, an attention 34, and an end of message 3.
5, the flag bits related to the negotiation 36 and the parameter 37 are included, and in this embodiment, the connection parameter exchange processing is performed by the flag bits related to the negotiation 36 and the parameter 37.

That is, the communication device requesting the other party to exchange the connection parameter transmits a packet with the negotiation bit 36 flagged, and the communication device receiving the packet with the negotiation bit 36 flagged in this way receives the flag. Based on the above, it determines whether or not the own device can meet the request. If the connection parameters can be exchanged, the communication device sends a parameter packet with a flag set in the parameter bit 37 to the other party, notifies the other party of its own connection parameter included in the parameter packet, and the connection parameter is transmitted. Perform the exchange of.

As shown in FIG. 4, the parameter packet stores its own connection parameters to be exchanged in the data field 24. The parameter ID specifies each connection parameter and the value of each connection parameter. And are stored as a pair.
Parameter IDs are pre-arranged at the time of mounting so as to match between communication devices, and in the present embodiment, connection parameters as shown in FIG. 8 are associated with the respective parameter IDs.

In the connection parameters as described above, for example, when trying to increase the transfer rate between communication devices, the maximum value of packet size and the window size are made as large as possible, and the transfer interval and the minimum retransmit interval are set. , Make the maximum retransmission interval and the number of retransmissions as small as possible,
Each connection parameter may be set between the communication devices so that the checksum is not executed.

Next, referring to FIG. 5, a packet exchanged between both communication devices will be described by taking an example of exchanging connection parameters between the front-end server 2 and the printer A so as to maximize the transfer rate. Explain. In this case, the connection parameters such as the maximum packet size, window size, transfer interval, minimum retransmission interval, maximum retransmission interval, number of retransmissions, and checksum that are initially set are as shown in FIG. For 2 respectively, 534 bytes, 5, 0 msec, 500
msec, 24000msec, 30, ON (present), and printer A has 1458byte, 14, 0msec, 50 respectively.
It is assumed that 0 msec, 24000 msec, 30, and ON (present).

First, when establishing a connection, the front-end server 2, which is a communication device on the transmission side, transmits a system packet (parameter exchange request) having a flag in the negotiation bit 36 to the printer A via the network 6. . Then, when the printer A receives this parameter exchange request, it determines whether its own device can respond to the exchange of connection parameters, and if this is possible, the system packet with the negotiation bit 36 flagged (parameter exchange request). Response) to the front-end server 2 via the network 6.

Next, when the front end server 2 receives this parameter exchange request response, it sends a parameter packet (parameter setting request) in which a flag is set in the parameter bit 37 and its own parameter value is stored in the data field 24 via the network 6. To printer A. Next, when the printer A receives this parameter setting request, it compares the sent connection parameter value of the front-end server 2 with its own, and determines which one of the connection parameter values that can increase the transfer rate is new. Set as a connection parameter value. Then, the printer A transmits the parameter packet (parameter setting request response) storing the connection parameter value newly set in the data field 24 with the flag set to the parameter bit 37 to the front end server 2 via the network 6.

In this case, the maximum packet size and window size set in the printer A are larger than those in the front-end server 2, and the other parameter values are the same for both printers. The parameter value is stored in the parameter setting request response and transmitted to the front-end server 2 without changing the parameter value. Then, when the front-end server 2 receives this parameter setting request response, it compares the connection parameter value of the printer A that has been sent with its own, and determines which one of the connection parameter values that can increase the transfer rate. Set as a new connection parameter value.

In this case, since the maximum value of the packet size and the window size of the printer A sent are larger than those of the front end server 2, the maximum value of the packet size and the window size currently set by the front end server 2 are set. To printer A's. As a result, the connection parameter between the front-end server 2 and the printer A is set to a matched value that maximizes the transfer rate. Therefore, thereafter, the packet (data packet) in which the predetermined data is stored in the data field 24 is transferred from the front end server 2 to the printer A at the maximum rate between them. Further, since the connection parameter set as described above becomes the maximum or minimum common divisor of the front-end server 2 and the printer A, the connection parameter consistency between the two is ensured and data transfer is smoothly performed. Done.

Next, the above-mentioned connection parameter exchange processing will be described in more detail by dividing it into the transmission side communication device (the above front end server 2) and the reception side communication device (the above printer A). The processing in the transmitting communication device is performed according to the procedure shown in the flowchart of FIG.
Immediately after the connection is established, the communication device on the transmission side sets a flag in the negotiation bit 36 of the system packet in the parameter exchange determination notifying unit 15, and sets the system packet as a parameter exchange request from the packet exchange control unit 13 to the network 6. It transmits to the receiving side communication apparatus via (step S1).

Next, when a response from the receiving side communication device to the parameter exchange request is sent, the packet exchange control unit 13 of the transmitting side communication device receives the parameter exchange request response from the network 6 (step S
2), the negotiation bit 36 of this response packet
Parameter exchange judgment notification unit 1
5 determines (step S3).

As a result, when the flag is not set, the communication device on the receiving side cannot respond to the exchange of connection parameters. Therefore, the communication device on the transmitting side transmits the data packet to the communication device on the receiving side according to the current connection parameter. Is started (step S8). On the other hand, when the flag is set, the receiving communication device is ready to exchange connection parameters, and therefore the transmitting communication device sets a flag in the parameter bit 37 of the packet by the parameter exchange determination notifying unit 15, Further, the packet switching control unit 13 stores the connection parameter currently set in the transmission side communication device in the data field 24 of this packet, and this parameter packet is used as a parameter setting request from the packet switching control unit 13 via the network 6. The data is transmitted to the receiving communication device (step S4).

Next, when a response from the receiving side communication device is sent to the parameter setting request, the packet switching control unit 13 of the transmitting side communication device receives the parameter setting request response from the network 6 (step S
5), the parameter setting unit 16 compares the connection parameter of the receiving side communication device stored in this response packet with the connection parameter currently set in its own device, and determines the optimum one from these parameter values. The connection parameter value currently set in its own device is updated (step S6). Then, the communication device on the transmission side sets the updated connection parameter in the communication driver of the packet switching control unit 13 (step S7), and starts transmission of the data packet to the communication device on the reception side according to the connection parameter (step S8). .

Next, the processing at the receiving side communication device is performed according to the procedure shown in the flowchart of FIG. First, when the receiving side communication device receives a parameter exchange request from the transmitting side communication device via the network 6 (step S11), based on the flag set in the negotiation bit 36 of this exchange request, the receiving side communication device The parameter exchange determination notification unit 15 determines whether or not a program capable of responding to this exchange request is installed in its own device (step S12).

As a result, if it is not implemented, the exchange of connection parameters cannot be accepted, so that the receiving side communication device receives the data packet sent from the transmitting side communication device according to the current connection parameter. Is started (step S18). On the other hand, when it is installed, it is in a state where it cannot respond to the exchange of connection parameters, so the parameter exchange determination notifying unit 15 of the receiving side communication device sets a flag in the negotiation bit 36 and sends this system packet to the parameter exchange request response. Is transmitted from the packet switching control unit 13 to the transmission side communication device via the network 6 (step S1).
3).

Then, when a parameter setting request is sent from the transmitting communication device, the packet switching control unit 13 of the receiving communication device receives this parameter setting request from the network 6 (step S14). Then, the parameter setting unit 16 of the receiving communication device compares the connection parameter of the transmitting communication device stored in the data field 24 of the parameter setting request with the connection parameter currently set in its own device, and The connection parameter value currently set in the own device is changed by the optimum one of the parameter values (step S15).

Here, as described in the example of FIG. 5, since the receiving side communication device does not need to change the connection parameter in order to increase the transfer rate, the currently set connection parameter is set in the data field 2.
4, and the parameter setting request response having the flag set in the parameter bit 37 is transmitted to the transmitting side communication device via the network 6 (step S16). In a general case, in order to realize the purpose from among the connection parameters set in the transmission side communication device or the reception side communication device, on the basis of a desired purpose such as increasing the transfer rate. A suitable one is selected and the value already set is updated with the selected connection parameter value.

Then, the receiving side communication device sets the updated connection parameter in the communication driver of the packet switching control unit 13 (step S17), and starts receiving the data packet sent from the transmitting side communication device according to this connection parameter. (Step S18). Therefore, when packet data is transferred from the transmitting communication device to the receiving communication device, the connection parameters of both communication devices are set to values that can realize the maximum transfer rate,
It is possible to quickly transfer large-sized data such as image data from the transmission side communication device to the reception side communication device.

The connection parameters are set by exchanging system packets and parameter packets between the transmitting side communication device and the receiving side communication device immediately after the connection is established. Transfer is realized automatically. When the sending communication device establishes a connection with another receiving communication device (that is, when the front-end processor 2 establishes a connection with another printer B or C in place of the printer A), Similarly, the optimum connection parameters are automatically set, and the optimum transfer is always realized automatically.

[0033]

As described above in detail, according to the present invention, when a communication device establishes a connection, the communication device inquires of the communication device of the other party, and based on the result of this inquiry, sets its own connection parameter for the other party. As a result, the optimum data transfer can be realized according to the nature of the transfer data, the status of the communication device of the other party, and the like. In particular, when a large size of data such as image data needs to be transferred, the transfer rate can be automatically increased as much as possible, and quick data transfer can be realized. Further, in a front-end server or the like that manages a plurality of printers, connection parameters suitable for each printer can be set, and the efficiency of data transfer as the entire system can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a communication network to which the present invention is applied.

FIG. 3 is a configuration diagram showing a packet format.

FIG. 4 is a configuration diagram showing a format of a parameter packet.

FIG. 5 is a conceptual diagram showing a flow of communication channel establishment processing.

FIG. 6 is a flowchart showing a packet processing procedure of the transmitting communication device.

FIG. 7 is a flowchart showing a packet processing procedure of the receiving communication device.

FIG. 8 is a diagram showing correspondence between parameter IDs and connection parameters.

[Explanation of symbols]

1-5 ... communication device, 6 ... network, 1
1 ... Network protocol control unit, 13 ...
Packet exchange control unit, 15 ... Parameter exchange determination notification unit, 16 ... Parameter setting unit

Claims (1)

[Claims] 1. A data transfer method for a communication device connected to a network, wherein upon establishment of a connection, the communication device of the other party is inquired about connection parameters that determine transfer conditions, and based on the result of this inquiry, the self communication device for the communication device of the other party is informed. Is set, and data is transferred to the communication device of the other party via the network based on the setting result.