WO2014175028A1

WO2014175028A1 - Communication apparatus and command transfer method

Info

Publication number: WO2014175028A1
Application number: PCT/JP2014/059794
Authority: WO
Inventors: 隆史磯部
Original assignee: 株式会社日立製作所
Priority date: 2013-04-25
Filing date: 2014-04-03
Publication date: 2014-10-30

Abstract

Provided is a communication apparatus for transferring commands between a server and a client terminal. The communication apparatus manages an upper-limit number of and a number of consumptions of commands transmitted/received between the server and the client terminal. The communication apparatus performs at least one of two comparisons: a comparison between an upper-limit number of and a number of consumptions of commands transmitted/received between the communication apparatus and the server; and a comparison between an upper-limit number of and a number of consumptions of commands transmitted/received between the communication apparatus and the client terminal. The communication apparatus then controls, on the basis of the result of said at least one of the two comparisons, the transfer of commands between the server and the client terminal.

Description

COMMUNICATION DEVICE AND COMMAND TRANSFER METHOD

Import by reference

This application claims the priority of Japanese Patent Application No. 2013-92564, which was filed on April 25, 2013, and is incorporated herein by reference.

The present invention relates to a communication device.

As a communication network between bases used for a cloud or the like, a WAN (Wide Area Network) using an IP-VPN (Internet Protocol-Virtual Private Network) technology or the like is generally used.

When the terminal of the first base communicates with the terminal of the second base, a line connecting the LAN of the first base and the WAN and a line connecting the WAN and the LAN of the second base Communication is performed via.

In communication between terminals, a file sharing protocol such as CIFS or NFS may be used. In the file sharing protocol, communication is performed by transferring a pair of request commands and response commands between terminals. Specifically, a request command is transmitted from the client terminal to the server, and the server transmits a response command corresponding to the received request command to the client terminal.

There is an upper limit on the number of request commands and response commands that can be transferred at one time between terminals. The server that has received a request command exceeding the upper limit transmits a response command notifying that there is an error to the client terminal.

When communicating between a client terminal and a server using a file sharing protocol, a relay device provided between the client terminal and the server sends a request command received from the client terminal and an additional request command to the server. There are cases (see Japanese Patent Application Publication No. 2008-537814).

When communicating between a client terminal and a server using a file sharing protocol, a relay device installed between the client terminal and the server sends a request command sent from the client terminal to the server, or from the server terminal to the client. Relay response commands sent to the terminal.

When the relay apparatus installed between the client terminal and the server receives a request command from the client terminal, the relay apparatus transfers the received request command to the server, and further transmits an additional request command to the server. At this time, the number of commands exchanged on the server side may be larger than the number of commands exchanged on the client side. For this reason, there may be a case where the server-side command count has reached the upper limit, but the client-side command count has not reached the upper limit.

In this state, when the client terminal transmits a new command, the upper limit of the number of commands that can be exchanged with the server is exceeded, and a response command for notifying an error is transmitted from the server to the client terminal. Once an error has occurred, there is a problem that the communication between the client terminal and the server is delayed, for example, the connection is forcibly disconnected and the performance deteriorates.

In the present invention, in view of the above points, the number of commands on the server side has reached the upper limit, but even when there is a mismatch in the state that the number of commands on the client side has not reached the upper limit, it can be exchanged between terminals at once The maximum number of commands is not exceeded, response commands that notify errors are prevented from being sent from the server to the client terminal, the connection is forcibly disconnected, and communication between the client terminal and the server is delayed. Thus, a relay device that prevents performance degradation is provided.

A typical example of the invention disclosed in the present application is as follows. That is, in a communication device that transfers commands between a server and a client terminal, the upper limit number and consumption number of commands exchanged between the server and the client terminal are managed, and the communication device and the server Compare at least one of the number of commands consumed and the maximum number of commands exchanged between them, and the number of commands consumed and the maximum number of commands exchanged between the communication device and the client terminal, and compare at least one of them Based on the result, the command transfer between the server and the client terminal is controlled.

According to the representative embodiment of the present invention, it is possible to prevent deterioration in communication performance between the client terminal and the server. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments.

It is a figure which shows the structural example of the relay system to which the relay apparatus of the Example of this invention is applied. It is a block diagram which shows the structure of the client terminal and server of a present Example. It is a block diagram which shows the structure of the relay apparatus of a present Example. It is a format figure of the packet which the relay apparatus of a present Example transmits / receives. It is a figure explaining the structure of the state management table of a present Example. It is a block diagram of the relay part in the relay apparatus of a present Example. It is a figure explaining the structure of the LAN upper limit / consumption number management table and WAN upper limit / consumption number management table of a present Example. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs. It is a sequence diagram by the process which the relay apparatus of a present Example performs. It is a flowchart of the process which the relay apparatus of a present Example performs.

FIG. 1 is a diagram illustrating a configuration example of a relay system to which a relay device 200 according to an embodiment of the present invention is applied.

The

relay devices

200A, 200B, and 200C (hereinafter, when the relay devices are not distinguished are denoted by reference numeral 200) are installed on communication lines that connect the

LANs

310, 320, and 330 and the WAN 340 in a plurality of bases. .

Terminals

311, 312, and 313 are connected to the LAN 310,

terminals

321, 322, and 323 are connected to the LAN 320, and

terminals

331, 332, and 333 are connected to the LAN 330. Each of the terminals 311 to 313, 321 to 323, and 331 to 333 may operate as a client terminal or as a server. Hereinafter, a case will be described in which the terminals connected to the LAN side of the

relay devices

200A, 200B, and 200C operate as client terminals, and the terminal connected to the WAN side operates as a server, but the

relay devices

200A, 200B, and 200C The same applies when a terminal connected to the LAN side operates as a server and a terminal connected to the WAN side operates as a client terminal.

FIG. 2 is a block diagram showing the configuration of the client terminal 701 and the server 702 of this embodiment.

In FIG. 2, only a configuration for communicating via the network 707 using a file sharing protocol such as CIFS or NFS is illustrated, and other configurations are omitted. Further, the relay device 200 is omitted for simplification of description.

In the file sharing protocol, communication is performed by transferring a pair of request commands and response commands between the client terminal 701 and the server 702. That is, a request command is transmitted from the client terminal 701 to the server 702. The server transmits a response command corresponding to the received request command to the client terminal.

The client terminal 701 has a command upper limit number that determines the upper limit of the number of request commands and response commands that can be exchanged with the server 702 at one time, and the number of request commands and responses that are actually exchanged with the server 702. The command consumption number in which the command number is recorded is recorded (703). The command consumption number increases when a request command is transmitted, and decreases when a response command is received. The command upper limit number increases or decreases when a response command is received.

The request transmission processing unit 705 receives the request command created by the request creation unit 708 and transmits the request command to the network 707. The request reception processing unit 710 receives the response command from the network 707 and transfers it to the request creation unit 708.

The server 702 also determines the command upper limit number that determines the upper limit of the number of request commands and response commands that can be exchanged between terminals at one time, and the number of request commands and response commands that are actually exchanged with the client terminal 701. The recorded command consumption number is recorded (704). The command consumption number increases when a request command is received, and decreases when a response command is transmitted. The command upper limit number increases or decreases when a response command is transmitted.

The request reception processing unit 706 receives a request command from the network 707 and transfers it to the response generation unit 709. The response transmission processing unit 711 receives the response command created by the response generation unit 709 and transmits the response command to the network 707. When the request reception processing unit 706 receives the quest command, the command consumption number increases, and when the command upper limit number is exceeded, the response generation unit 709 generates a response command to notify that there is an error, and the response transmission processing unit 711 to the client terminal 701.

FIG. 3 is a block diagram illustrating a configuration of the relay apparatus 200 according to the present embodiment.

The relay apparatus 200 includes a LAN interface 201, a filter 202, a LAN TCP processing unit 203, LAN side reception buffers 204-1 to N, LAN side transmission buffers 205-1 to N, WAN side transmission buffers 207-1 to N, and WAN side. The reception buffer 208-1 to N, the WAN TCP processing unit 209, the filter 210, the WAN interface 211, the relay unit 100, and the state management table 400 are included.

The LAN interface 201 transmits and receives packets to and from the

LANs

310, 320, and 330. The WAN interface 211 transmits and receives packets to and from the WAN 340. The

filters

202 and 210 transfer packets that are not specially processed by the relay apparatus 200 (for example, ARP packets) between the filters, and transfer the packets without passing through the relay unit 100. The LAN TCP processing unit 203 and the WAN TCP processing unit 209 perform control for TCP communication.

LAN side reception buffers 204-1 to 204-1 and LAN side transmission buffers 205-1 to N are buffers that are managed by the LAN TCP processing unit 203 and temporarily store transmission packets and reception packets, respectively. The WAN-side reception buffers 208-1 to 208-N and the WAN-side transmission buffers 207-1 to N are managed by the WAN TCP processing unit 209, and are buffers that temporarily store transmission packets and reception packets, respectively. The number of transmission / reception buffers may be different.

The relay unit 100 relays commands between the transmission buffer and the reception buffer. The state management table 400 includes a plurality of entries and manages the state of the communication connection. The number of entries in the state management table 400 may be different from the number of transmission / reception buffers.

The functions of each unit of the relay device 200 described above may be implemented by hardware modules or software modules.

The LAN TCP processing unit 203 stores the received packet (data) in the LAN side reception buffers 204-1 to 204-1 and transmits the transmission data read from the LAN side transmission buffers 205-1 to N in the form of packets. The WAN TCP processing unit 209 stores the received packet (data) in the WAN side reception buffers 208-1 to 208-1 to N, and transmits the transmission data read from the WAN side transmission buffers 207-1 to N in the form of packets. The relay unit 100 reads the command data from the reception buffers 204-1 to N and 208-1 to N, and writes the command data to the transmission buffers 207-1 to N and 205-1 to N. Details of the operation of the relay unit 100 will be described later.

FIG. 4 is a format diagram of a packet transmitted and received by the relay apparatus 200 according to the present embodiment.

The packet includes a MAC header 500, an IP header 510, a TCP header 520, a TCP option header 530, and a request / response command 550.

The MAC header 500 includes a DMAC 501 that represents a destination MAC address, an SMAC 502 that represents a source MAC address, and a Type 503 that represents a MAC frame type. The IP header 510 includes an IP length 511 representing the packet length excluding the MAC header, a protocol 512 representing the protocol number, a SIP 513 representing the source IP address, and a DIP 514 representing the destination IP address.

TCP header 520 is a src. port 521, dst. port 522, SEQ 523 representing a transmission sequence number, and ACK 524 representing a reception sequence number. The TCP option header 530 is a header having a maximum of 40 bytes.

The request / response command 550 is a request / response command transferred between terminals using a file sharing protocol. The request / response command 550 includes a request 551 indicating a request command, a response 552 indicating a response command, a type 553 specifying a command type, and a credits number 554 specifying an increase / decrease value of the command upper limit number in the response command.

In Type 553, values for specifying Read for reading a file, Write for writing to a file, Create for opening a file, Close for closing a file, and the like are described.

The credits number 554 is a value greater than or equal to 0, and is used to increase or decrease the command upper limit number. For example, if credits number 554 is 0, the command upper limit number is specified to be decreased by 1, and if credits number 554 is 1, the command upper limit number is specified to be unchanged, and credits number 554 is 2 If the credits number 554 is 32, the command upper limit number is specified to be increased by 31.

The content of the request / response command 550 may be mounted in only one packet or may be divided into a plurality of packets and mounted.

FIG. 5 is a diagram illustrating the configuration of the state management table 400 according to the present embodiment.

The state management table 400 of the relay device 200 includes, for example, n entries 400-i (i = 1 to n) for recording the state of each TCP connection.

Each entry 400-i includes, for example, VLD401, connect_state402, LIP403, WIP404, Lport405, Wport406, lan_state407, lan_left_rbuf408, lan_left_recv409, lan_right_recv410, lan_left_send414, lan_right_send415, lan_right_sbuf416, wan_state420, wan_left_rbuf421, wan_left_recv422, wan_right_recv423, wan_left_send427, the wan_right_send428 and wan_right_sbuf429 .

VLD 401 indicates whether an entry is in use. The connect_state 402 represents whether or not a connection on the LAN or WAN side is being established. LIP 403 represents the IP address of the terminal on the LAN side. WIP 404 represents the IP address of the terminal on the WAN side. Lport 405 represents the TCP port number of the terminal on the LAN side. Wport 406 represents the TCP port number of the terminal on the WAN side.

Lan_state 407 represents the state of TCP communication on the LAN side. lan_left_rbuf 408, lan_left_recv 409, and lan_right_recv 410 represent pointers for reception buffer management on the LAN side. lan_left_send 414, lan_right_send 415, and lan_right_sbuf 416 represent pointers for LAN-side transmission buffer management.

Wan_state 420 represents the state of TCP communication on the WAN side. wan_left_rbuf 421, wan_left_recv 422, and wan_right_recv 423 represent a reception buffer management pointer on the WAN side. wan_left_send 427, wan_right_send 428, and wan_right_sbuf 429 represent WAN transmission buffer management pointers.

A data flow from the LAN to the WAN in the relay apparatus 200 will be described with reference to FIG.

The packet with data arriving from the LAN side is input to the LAN TCP processing unit 203. The LAN TCP processing unit 203 returns an ACK packet to the LAN side, and stores the data described in the packet in the LAN side reception buffers 204-1 to 204-N. Further, the LAN side reception buffer management pointer of the state management table 400 is updated based on the size of the stored data.

The LAN side receive buffer management pointers are, in order from the smallest, lan_left_rbuf 408 indicating the boundary between the data already read by the relay unit 100 and the data not yet read, the pointer lan_left_recv 409 indicating the boundary between the aligned data and the unaligned data, and the received data A pointer lan_right_recv 410 indicating the end of the.

The pointer lan_left_recv 409 indicating the boundary between the aligned data and the unaligned data and the pointer lan_right_recv 410 indicating the end of the received data are increased by the received data size when the data is received in order from the front without packet discarding.

When a data portion (loss segment) that cannot be received due to packet discard or the like is lost, a pointer lan_right_recv 410 indicating the end of the received data is increased by the received data size. When a retransmission packet is received in a state where a loss segment exists and all the loss segments disappear, the pointer lan_left_recv 409 indicating the boundary between the aligned data and the unaligned data increases to lan_right_recv410.

The relay unit 100 reads data sequentially in an increasing direction from lan_left_rbuf 408 indicating the boundary between read data and unread data, and increases lan_left_rbuf 408 by the read data size. The maximum data size that can be newly read is the difference between lan_left_rbuf 408 and lan_left_recv 409.

The relay unit 100 reads the aligned data stored in the LAN side reception buffers 204-1 to 204-N for each request command and writes it to the WAN side transmission buffers 207-1 to 207-1. The WAN TCP processing unit 209 reads data from the WAN side transmission buffers 207-1 to 207-1 to N, transmits the read data as a packet, and transmits a packet with data to which the TCP header 520 is added to the WAN side. Further, the WAN side transmission buffer management pointer of the state management table 400 is updated based on the transmission data size.

The WAN side transmission buffer management pointers are, in ascending order, a pointer wan_right_sbuf 429 indicating the end of data written from the relay unit 100 and ready for transmission, a pointer wan_right_send 428 indicating the end of transmitted data, and an acknowledgment from the reception side. Includes a pointer wan_left_send 427 indicating the end of the received data.

The pointer wan_right_sbuf 429 indicating the end of data written from the relay unit 100 and ready for transmission increases by the written data size each time the relay unit 100 newly writes data. New data is read in an increasing direction starting from a pointer wan_right_send 428 indicating the end of the transmitted data, and transmitted to the WAN side with a packet header added. The wan_right_send 428 increases by the transmitted data size. When an acknowledgment packet having a reception sequence number larger than wan_left_send 427 is received from the WAN side, wan_left_send 427 increases to the reception sequence number described in the acknowledgment packet.

Further, a data flow from the WAN to the LAN in the relay apparatus 200 will be described with reference to FIG.

The packet with data arriving from the WAN side is input to the WAN TCP processing unit 209. The WAN TCP processing unit 209 returns an ACK packet to the WAN side, and stores the data described in the packet in the WAN side reception buffers 208-1 to 208-N. Further, the WAN reception buffer management pointer of the state management table 400 is updated based on the accumulated data size.

WAN side receive buffer management pointers are received in order from the smallest, wan_left_rbuf 421 indicating the boundary between the data that has already been read by the relay unit 100 and the data not yet read, the pointer wan_left_recv 422 indicating the boundary between the aligned data and the unaligned data, and received It includes a pointer wan_right_recv 423 indicating the end of the data. The pointer wan_left_recv 422 indicating the boundary between the aligned data and the unaligned data and the pointer wan_right_recv 423 indicating the end of the received data are increased by the received data size when the data is received in order from the front without packet discarding.

When a data portion (loss segment) that cannot be received due to packet discard or the like is lost, a pointer wan_right_recv 423 indicating the end of the received data increases by the received data size. When a re-transmission packet is received in a state where a loss segment exists and all the loss segments disappear, the pointer wan_left_recv 422 indicating the boundary between the aligned data and the unaligned data increases to wan_right_recv 423.

The relay unit 100 reads data sequentially in an increasing direction from wan_left_rbuf 421 indicating the boundary between read data and unread data, and increases wan_left_rbuf 421 by the read data size. The maximum data size that can be newly read is the difference between wan_left_rbuf 421 and wan_left_recv 422.

The relay unit 100 reads the aligned data stored in the WAN side reception buffers 208-1 to 208-N for each request command, and writes it to the LAN side transmission buffers 205-1 to N. The LAN TCP processing unit 203 reads data from the LAN-side transmission buffers 205-1 to 205-N, transmits the read data as a packet, and transmits a packet with data to which the TCP header 520 is added to the LAN side. Further, the LAN side transmission buffer management pointer of the state management table 400 is updated based on the transmission data size.

The LAN side transmission buffer management pointers are, in ascending order, a pointer lan_right_sbuf 416 indicating the end of data written from the relay unit 100 and ready for transmission, a pointer lan_right_send 415 indicating the end of transmitted data, and an acknowledgment from the reception side. There is a pointer lan_left_send 414 indicating the end of the data that has been received.

The pointer lan_right_sbuf 416 indicating the end of data written from the relay unit 100 and ready for transmission increases by the written data size each time the relay unit 100 newly writes data. New data is read in an increasing direction starting from a pointer lan_right_send 415 indicating the end of transmitted data, and transmitted to the WAN side with a packet header added. lan_right_send 415 increases by the transmitted data size. When an acknowledgment packet having a reception sequence number larger than lan_left_send 414 is received from the LAN side, lan_left_send 414 increases to the reception sequence number described in the acknowledgment packet.

FIG. 6 is a block diagram of the relay unit 100 in the relay device 200 of this embodiment.

The relay unit 100 includes a LAN side relay unit 110, a WAN side relay unit 120, a LAN upper limit / consumption number management table 600, and a WAN upper limit / consumption number management table 601.

The LAN upper limit / consumption count management table 600 manages the command upper limit count and consumption count on the LAN side. The WAN upper limit / consumption number management table 601 manages the command upper limit number and consumption number on the WAN side.

The LAN-side relay unit 110 includes a reception buffer 111, a request reception processing unit 112, a response transmission processing unit 113, a request creation unit 114, an aggregation unit 115, a response creation unit 116, and a request creation unit 117.

The reception buffer 111 stores the request command read from the LAN side reception buffer 204. The request reception processing unit 112 reads a request command from the reception buffer 111 and determines a transfer destination and transfer timing. The request creation unit 117 creates a new request command based on the request command transferred from the request reception processing unit 112. The response creation unit 116 creates a new response command based on the request command transferred from the request reception processing unit 112. The aggregating unit 115 aggregates the response command created by the response creating unit 116 and the response command transferred from the WAN side relay unit 120. The response transmission processing unit 113 receives the response command transferred from the aggregation unit and transfers the response command to the LAN side transmission buffer 205 and the request creation unit 114. The request creation unit 114 creates a new request command based on the response command transferred from the response transmission processing unit 113.

The WAN-side relay unit 120 includes a request transmission processing unit 121, an aggregation unit 122, a response reception processing unit 123, and a reception buffer 124.

The reception buffer 124 stores the response command read from the WAN side reception buffer 208. The response reception processing unit 123 reads the response command from the reception buffer 124 and transfers it to the LAN side relay unit 110. The aggregation unit 122 aggregates request commands transmitted from the request reception processing unit 112, the request creation unit 117, and the request creation unit 114 of the LAN side relay unit 110. The request transmission processing unit 121 receives the request command transferred from the aggregation unit and transfers it to the WAN side transmission buffer 207.

The functions of each unit of the relay unit 100 described above may be implemented by hardware modules or software modules.

FIG. 7 is a diagram illustrating the configuration of the LAN upper limit / consumption number management table 600 and the WAN upper limit / consumption number management table 601 according to this embodiment.

The LAN upper limit / consumption number management table 600 includes a LAN side command upper limit number 602 and a LAN side command consumption number 603. The command upper limit number 602 defines an upper limit value of the number of commands that can be exchanged on the LAN side. The command consumption number 603 records the number of commands exchanged on the LAN side.

When receiving a request command from the LAN side, the request reception processing unit 112 of the LAN side relay unit 110 increments the command consumption number 603. When the response transmission processing unit 113 of the LAN side relay unit 110 transmits a response command to the LAN side, the command consumption number 603 is decremented.

Furthermore, the request reception processing unit 112 changes the command upper limit number 602. For example, if the value described in credits number 554 in the field of response command 550 transmitted to the LAN side is 0, the command upper limit number 602 is decreased by 1, and if it is 2, the command upper limit number 602 is increased by 1, If there is, the command upper limit number 602 is increased by 31.

The WAN upper limit / consumption number management table 601 includes a WAN side command upper limit number 604 and a WAN side command consumption number 605. The command upper limit number 604 defines an upper limit value of the number of commands that can be exchanged on the WAN side. The command consumption number 605 records the number of commands exchanged on the WAN side.

The request transmission processing unit 121 of the WAN side relay unit 120 increments the command consumption number 605 when a request command is transmitted to the WAN side. When receiving the response command from the WAN side, the response reception processing unit 123 of the WAN side relay unit 120 decrements the command consumption number 605.

Furthermore, the request transmission processing unit 121 changes the command upper limit number 604. For example, it is described in credits number 554 in the response command 550 field received from the WAN side, but if it is 0, the command upper limit number 604 is decreased by 1, and if it is 2, the command upper limit number 604 is increased by 1, For example, the command upper limit number 604 is increased by 31.

As described above, the relay apparatus 200 according to the present embodiment changes the command consumption number and the upper limit number using the LAN upper limit / consumption number management table 600 and the WAN upper limit / consumption number management table 601. That is, when a command is received from the client terminal 701, the LAN side command consumption number 603 is increased, and when a command is transmitted to the client terminal 701, the LAN side command consumption number 603 is decreased. Further, according to the command received from the client terminal 701, the LAN side command upper limit number 602 is increased or decreased. Further, the WAN side command consumption number 605 is increased when a command is transmitted to the server 702, and the WAN side command consumption number 605 is decreased when a command is received from the server 702. Further, according to the command received from the server 702, the WAN side command upper limit number 604 is increased or decreased.

In the relay apparatus 200 of this embodiment, the request reception processing unit 112 of the LAN side relay unit 110 compares the command upper limit number 602 and the command consumption number 603 in the LAN upper limit / consumption number management table 600. If the command consumption number 603 is equal to the command upper limit number 602, the request reception processing unit 112 stops reading the request command from the reception buffer 111. On the other hand, when the command consumption number 603 is smaller than the command upper limit number 602, the request reception processing unit 112 reads the request command from the reception buffer 111. Thereby, when the command consumption number of the LAN is equal to the upper limit number, the request command received from the LAN is stored in the reception buffer 111 without performing the request command reception process. On the other hand, when the command consumption number of the LAN is smaller than the upper limit number, a request command from the LAN is read from the reception buffer 111, and a request command reception process is performed.

In the relay apparatus 200 of this embodiment, the request transmission processing unit 121 of the WAN-side relay unit 120 compares the command upper limit number 604 and the command consumption number 605 in the WAN upper limit / consumption number management table 601. Then, when the command consumption number 605 is equal to the command upper limit number 604, the request transmission processing unit 121 stops the transfer of the request command to the WAN side transmission buffer 207. On the other hand, when the command consumption number 605 is smaller than the command upper limit number 604, the request transmission processing unit 121 transfers the request command to the WAN side transmission buffer 207. Thereby, when the command consumption number on the WAN side is equal to the upper limit number, the request transmission process to the WAN is stopped, and when the command consumption number on the WAN side is smaller than the upper limit number, the request transmission process to the WAN is performed.

Furthermore, in the relay device 200 of this embodiment, the request reception processing unit 112 of the LAN side relay unit 110 compares the command upper limit number 604 and the command consumption number 605 in the WAN upper limit / consumption number management table 601. When the command consumption number 605 is equal to the command upper limit number 604, reading of the request command from the reception buffer 111 is stopped. On the other hand, when the command consumption number 605 is smaller than the command upper limit number 604, the request reception processing unit 112 reads the request command from the reception buffer 111. Thus, when the command consumption number on the WAN side is equal to the upper limit number, the request command received from the LAN is stored in the reception buffer 111 without performing the request command reception process from the LAN. On the other hand, when the command consumption number on the WAN side is smaller than the upper limit number, a request command from the LAN is read from the reception buffer 111 and a request command reception process is performed.

In the relay apparatus 200 of the present embodiment, the response transmission processing unit 113 of the LAN side relay unit 110 determines the difference between the command upper limit number 604 and the command consumption number 605 in the WAN upper limit / consumption number management table 601 and the LAN upper limit / The difference between the command upper limit number 602 and the command consumption number 603 in the consumption number management table 600 is compared. When the difference between the command upper limit number and the consumption number on the WAN side is larger than the difference between the command upper limit number and the consumption number on the LAN side, the response transmission processing unit 113 sets the value of the credits number 554 of the response command to be transmitted to the LAN side. Rewrite it to a larger value to increase the command limit on the LAN side. On the other hand, if the difference between the command limit on the WAN side and the consumption count is smaller than the difference between the command limit on the LAN side and the consumption count, the response transmission processing unit 113 sets the value of the credits number 554 of the response command to be transmitted to the LAN side. Rewrite to a smaller value to reduce the command limit on the LAN side. As a result, the field related to increase / decrease of the upper limit number described in the response command transmitted to the LAN side is changed, and the difference between the upper limit number of commands and the consumption number on the WAN side is the difference between the upper limit number of commands on the LAN side and the consumption number Can be matched. Further, the relay apparatus 200 can match the state of the command upper limit number and the consumption number on the LAN side and the WAN side, the command consumption number exceeds the upper limit number on the WAN side, or the command upper limit number on the LAN side. Can be prevented.

In the relay apparatus 200 of this embodiment, the request creation unit 117 of the LAN side relay unit 110 compares the command upper limit number 604 and the command consumption number 605 in the WAN upper limit / consumption number management table 601. When the command consumption number 603 is equal to the command upper limit number 602, the creation of a new request to the WAN is stopped. On the other hand, when the command consumption number 605 is smaller than the command upper limit number 604, the request creation unit 117 creates a new request to the WAN. As a result, if the upper limit number of commands on the WAN side and the number of consumptions match, creation of a new request to the WAN triggered by reception of a request from the LAN is stopped. On the other hand, when the number of commands consumed on the WAN side is smaller than the upper limit number, a new request to the WAN is created triggered by reception of a request from the LAN.

In the relay device 200 of this embodiment, the response creation unit 116 of the LAN side relay unit 110 compares the command upper limit number 604 and the command consumption number 605 in the WAN upper limit / consumption number management table 601. When the command consumption number 603 is equal to the command upper limit number 602, the creation of a new response to the LAN is stopped. When the command consumption number 605 is smaller than the command upper limit number 604, a new response to the LAN is created. As a result, when the upper limit number of commands on the WAN side and the number of consumptions match, creation of a response to the LAN triggered by reception of a request from the LAN is stopped. On the other hand, if the number of commands consumed on the WAN side is smaller than the upper limit number, a response to the LAN is created using a request reception from the LAN as a trigger.

In the relay device 200 of this embodiment, the request creation unit 114 of the LAN-side relay unit 110 compares the command upper limit number 604 and the command consumption number 605 in the WAN upper limit / consumption number management table 601. When the command consumption number 603 is equal to the command upper limit number 602, the creation of a new request to the WAN is stopped. On the other hand, when the command consumption number 605 is smaller than the command upper limit number 604, the request creation unit 114 creates a new request to the WAN. As a result, when the upper limit number of commands on the WAN side and the number of consumptions match, creation of a new request to the WAN triggered by response transmission to the LAN is stopped. On the other hand, when the number of commands consumed on the WAN side is smaller than the upper limit number, a new request to the WAN is created using a response transmission to the LAN as a trigger.

When the request creation unit 114 and the request creation unit 117 of the LAN side relay unit 110 described above match the upper limit number of commands on the WAN side and the consumption number, the creation of new requests to the WAN is stopped, and the command consumption number on the WAN side If the number is less than the upper limit, a new request can be created to the WAN.

Hereinafter, specific examples of the processing procedure of the relay device 200 and seven examples of effects to be realized will be described in detail.

First, using FIG. 8 and FIG. 9, the first example of the processing procedure performed by the relay apparatus of the present embodiment and the realized effect will be described in detail.

FIG. 8 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 9 is a flowchart of processing performed by the relay device of this embodiment.

A server 702 is connected to the WAN side of the relay apparatus 200, and a client terminal 701 is connected to the LAN side.

First, a relay device 200 installed between a client terminal 701 and a server 702 that communicate using a file sharing protocol receives a request command from the client terminal 701 to the server 702, and a response command from the server 702 to the client terminal 701. The function of relaying will be described.

For example, when transferring a file read request from the client terminal 701, the relay apparatus 200 transmits a request for prefetching subsequent data to the server 702 with the transmission of the file read request as a trigger.

Specifically, when relay apparatus 200 relays request command (A) 1001 transmitted from client terminal 701 to server 702, three request commands (a-1 to a-3) 1003 to 1005 are newly added. Is transmitted to the server 702. Note that the transfer of the request command (A) 1001 from the relay apparatus 200 to the server 702 is not shown.

In this case, the number of command consumption on the server side is 4, but the number of command consumption on the client side is 1, and a state mismatch occurs. When the relay apparatus 200 receives response commands for all request commands from the server 702, the number of command consumptions on the server side becomes zero. Furthermore, when the relay apparatus 200 transmits a response command to the request command (A) 1001 to the client terminal 701, the number of commands consumed on the client side is also zero.

Specifically, in a state where the upper limit number of commands on the WAN side is larger than the consumption number (1002), the relay apparatus 200 receives the request command (A) 1001 from the client terminal 701, and newly adds three request commands (a− 1 to a-3) 1003 to 1005 are generated and transmitted to the server 702. As a result, the command consumption number on the WAN side becomes equal to the upper limit number (1006).

After that, when the relay apparatus 200 is waiting for the arrival of the request command from the client terminal 701 (step 2101) and receives the request command (B) 1007 from the client terminal 701, the relay apparatus 200 receives the request from the WAN side. It is determined whether the command consumption number is equal to the upper limit number (step 2102). As a result, when the command consumption number on the WAN side is equal to the upper limit number, the request command (B) 1007 is stored in the reception buffer 111, and it is repeatedly determined whether the command consumption number on the WAN side is equal to the upper limit number.

Thereafter, a response command (a-1) 1008 is received from the server 702, and when the number of commands consumed on the WAN side becomes smaller than the upper limit number (1009), the request reception processing unit 112 receives the request command (B) stored in the reception buffer 111. 1007 is read and transferred to the request transmission processing unit 121 (step 2103). The request transmission processing unit 121 transfers the transferred request command (B) 1007 as a request command (B) 1010 to the WAN side.

As described above, when the command consumption number on the WAN side is equal to the upper limit number, the received request command is stored in the buffer without receiving the request command from the LAN. When the command consumption number on the WAN side becomes smaller than the upper limit number, the request command from the LAN is read from the buffer and the reception process is resumed. As a result, it is possible to prevent the occurrence of an error and the forced disconnection of the connection due to the command consumption number on the WAN side being larger than the upper limit number, and it is possible to prevent the performance deterioration due to the communication delay between the client terminal and server.

Furthermore, a second example of the processing procedure performed by the relay apparatus of the present embodiment and the effect to be realized will be described in detail with reference to FIGS.

FIG. 10 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 11 is a flowchart of processing performed by the relay device according to this embodiment.

In a state where the command consumption number on the WAN side is equal to the upper limit number (1202), the relay apparatus 200 is waiting for a request command that triggers response command generation to arrive from the client terminal 701 (step 2301). In this state, when the relay apparatus 200 receives the request command (A) 1201 from the client terminal 701, the request reception processing unit 112 accumulates the received request command (A) 1201 in the reception buffer 111 and sends it to the response creation unit 116. Transfer (step 2302).

The response creation unit 116 returns a response command (A) 1203 to the LAN side based on the transferred request command (A) 1201.

The request reception processing unit 112 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 2303), and the request command stored in the reception buffer 111 (until the command consumption number on the WAN side becomes smaller than the upper limit number). A) The reading of 1201 is stopped. Meanwhile, on the LAN side, the request command (A) 1201 is not relayed on the WAN side even though the response of the response command (A) 1203 to the request command (A) 1201 has been completed. Occurs (1204). If this discrepancy is over a long period of time, the risk of failure increases.

Thereafter, when the relay device 200 receives the response command 1206 from the server 702 and the WAN side command consumption number becomes smaller than the upper limit number (1205), the request reception processing unit 112 resumes reading the request command stored in the reception buffer 111. Then, the read request command (A) 1201 is transferred to the request transmission processing unit 121 (step 2304).

On the other hand, in the above-described embodiment, even if the response of the response command to the request command is completed on the LAN side, the WAN does not transmit a corresponding request command, and a state mismatch occurs over a long period of time. There is a problem that the risk when the relay device 200 breaks down increases.

An embodiment for solving the above-described problem will be described in detail with reference to FIGS. It is the 3rd example of the process procedure which the relay apparatus of this Example performs, and the effect implement | achieved.

FIG. 12 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 13 is a flowchart of processing performed by the relay device of this embodiment.

In a state where the command consumption number on the WAN side is equal to the upper limit number (1302), the relay apparatus 200 waits for a request command that triggers response command generation to arrive from the client terminal 701 (step 2401). In this state, when the relay apparatus 200 receives the request command (A) 1301 from the client terminal 701, the request reception processing unit 112 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 2402), and WAN Reading of the request command (A) 1301 accumulated in the reception buffer 111 is stopped until the command consumption number on the side becomes smaller than the upper limit number.

Thereafter, when the relay apparatus 200 receives the response command 1303 from the server 702 and the WAN command consumption number becomes smaller than the upper limit number (1304), the request reception processing unit 112 resumes reading the request command stored in the reception buffer 111. Then, the read request command (A) 1301 is transferred to the response creation unit 116 and the request transmission processing unit 121 (step 2403, step 2404).

The response creation unit 116 returns a response command (A) 1305 to the LAN side based on the transferred request command (A) 1301. The request transmission processing unit 121 transmits the transferred request command (A) 1301 to the WAN side.

In this way, when the number of commands consumed on the WAN side is equal to the upper limit number, the response command response to the LAN triggered by reception of the request command from the LAN is stopped. Also, when the command consumption number on the WAN side is smaller than the upper limit number, the response command return process to the LAN triggered by reception of the request command from the LAN is resumed. For this reason, when the response of the response command to the request command is completed on the LAN side, it is possible to prevent the state mismatch that the corresponding request command is not transmitted on the WAN side from occurring for a long time. The risk at the time of failure can be reduced.

FIG. 14 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 15 is a flowchart of processing performed by the relay device of this embodiment.

In a state where the command consumption number on the WAN side is equal to the upper limit number (1503), the relay apparatus 200 waits for a request command that triggers generation of a request command to arrive from the client terminal 701 (step 2601). In this state, the relay apparatus 200 receives the request command (A) 1501 from the client terminal 701, and then receives the request command (B) 1502.

The request reception processing unit 112 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 2602), and the request command stored in the reception buffer 111 (until the command consumption number on the WAN side becomes smaller than the upper limit number). A) Stop reading 1501. Thereafter, when the response reception processing unit 123 receives the response command 1505 from the server 702 and the WAN side command consumption number becomes smaller than the upper limit number (1504), the request reception processing unit 112 reads the request command stored in the reception buffer 111. And the read request command (A) 1501 is transferred to the request creation unit 117 (step 2603).

The request creation unit 117 newly generates three request commands (a-1) 1506, (a-2) 1508, and (a-3) 1510 (step 2604). Thereafter, the request creation unit 117 determines whether the command consumption number on the WAN side is equal to the upper limit number (Step 2605), and the command transmission number on the WAN side becomes one smaller than the upper limit number. Then, the request command (a-1) 1506, which is one of the created request commands, is transferred to the request transmission processing unit 121 (step 2606).

When the request transmission processing unit 121 transmits the request command (a-1) 1506 to the WAN, the number of commands consumed on the WAN side increases by one, and the number of commands consumed on the WAN side becomes equal to the upper limit number.

The request transmission processing unit 121 determines whether there is a new request command that has not been transmitted (step 2607), and since the two newly generated request commands have not been transmitted, the command consumption number on the WAN side is again equal to the upper limit number. Is determined (step 2605). As a result, the request transmission processing unit 121 stops the transfer of the newly generated request command to the request transmission processing unit 121 and waits until the command consumption number on the WAN side becomes smaller than the upper limit number.

After that, when the relay apparatus 200 receives the response command 1507 from the server 702 and the number of commands consumed on the WAN side becomes one less than the upper limit number, a request command (a-2) 1508 which is one of newly generated request commands is obtained. It is transferred to the request transmission processing unit 121 (step 2606).

When the request transmission processing unit 121 transmits the request command (a-2) 1508 to the WAN, the number of commands consumed on the WAN side increases by one, and the number of commands consumed on the WAN side again becomes equal to the upper limit number.

The request transmission processing unit 121 determines whether there is a new request command that has not been transmitted (step 2607). Since one newly generated request command has not been transmitted, the command consumption number on the WAN side is again equal to the upper limit number. Is determined (step 2605). The request transmission processing unit 121 stops transfer of the newly generated request command to the request transmission processing unit 121 and waits until the command consumption number on the WAN side becomes smaller than the upper limit number.

After that, when the relay apparatus 200 receives the response command 1509 from the server 702 and the number of commands consumed on the WAN side becomes smaller than the upper limit number, the request command (a-3) 1510 which is the last one of the newly generated request commands is It is transferred to the request transmission processing unit 121 (step 2606).

When the request transmission processing unit 121 transmits the request command (a-3) 1510 to the WAN, the number of commands consumed on the WAN side increases by one, and the number of commands consumed on the WAN side again becomes equal to the upper limit number.

The request transmission processing unit 121 determines whether there is a new request command that has not been transmitted (step 2607). When there is no new request command that has not been transmitted, the transmission of the newly generated request command is terminated.

Thereafter, when the relay apparatus 200 receives the response command 1512 from the server 702 and the WAN command consumption number becomes smaller than the upper limit number, the request transmission processing unit 121 sets the request command (B) 1502 as the request command (B) 1513 and the WAN. To the side.

As described above, when the upper limit number is equal to the command consumption number on the WAN side, the transfer of the newly generated request command to the WAN with the request command from the LAN as a trigger is stopped, and the WAN command consumption number is the upper limit number. When it becomes smaller, transfer of request command is resumed. This prevents the occurrence of errors and forced disconnection due to the number of commands consumed on the WAN side exceeding the upper limit, and prevents performance degradation due to communication delay between the client terminal and the server. it can.

On the other hand, in the above-described embodiment, subsequent request commands received from the LAN side are not transferred to the WAN until all new commands generated by using the request command from the LAN as a trigger are transferred to the WAN, and the command response time is There is a problem of deterioration.

An embodiment that solves the above-described problem will be described in detail with reference to FIGS. It is the 3rd example of the process procedure which the relay apparatus of this Example performs, and the effect implement | achieved.

FIG. 16 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 17 is a flowchart of processing performed by the relay device of this embodiment.

In a state where the command consumption number on the WAN side is equal to the upper limit number (1603), the relay apparatus 200 is waiting for a request command that triggers generation of a request command to arrive from the client terminal 701 (step 2701). In this state, the relay apparatus 200 receives the request command (A) 1601 from the client terminal 701, and then receives the request command (B) 1602.

The request reception processing unit 112 determines whether the command consumption number on the WAN side is equal to the upper limit number (Step 2702), and the request command stored in the reception buffer 111 (until the command consumption number on the WAN side becomes smaller than the upper limit number). A) The reading of 1601 is stopped. After that, when the response reception processing unit 123 receives the response command 1605 from the server 702 and the number of commands consumed on the WAN side becomes smaller than the upper limit number (1604), the request reception processing unit 112 reads the request command stored in the reception buffer 111. And the read request command (A) 1601 is transferred to the request creation unit 117 (step 2703).

Upon receiving the request command (A) 1601, the request creation unit 117 determines whether there is a request to be newly created using the request command (A) 1601 as a trigger (step 2704). As a result, when there is a request to be newly generated, the request creation unit 117 newly creates one request command (a) 1606 (step 2705).

The request creation unit 117 transfers the newly created request command (a) 1606 to the request transmission processing unit 121 (step 2706). The request transmission processing unit 121 transmits a new request command (a) 1606 to the WAN.

When the request transmission processing unit 121 transmits the request command (a) 1606 to the WAN, the number of commands consumed on the WAN side increases by one, and the number of commands consumed on the WAN side becomes equal to the upper limit number.

Thereafter, the request creation unit 117 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 2707). If the command consumption number on the WAN side becomes smaller than the upper limit number, is there a request to be newly created? Is determined (step 2704). As a result, if there is an uncreated new request, a new request command is created again (step 2705). On the other hand, when the command consumption number on the WAN side is equal to the upper limit number, the creation of a new request command using the request command (A) 1601 as a trigger ends.

After that, when the command reception number on the WAN side is equal to the upper limit number (1604) and the response reception processing unit 123 receives the response command 1607, the command consumption number on the WAN side becomes one smaller than the upper limit number. When the command consumption number on the WAN side becomes smaller than the upper limit number, the request reception processing unit 112 reads the request command (B) 1602 from the reception buffer 111 and transfers it to the request transmission processing unit 121. The request transmission processing unit 121 transmits a request command (B) 1602 as a request command B 1608 to the WAN.

As described above, when the command consumption number on the WAN side is equal to the upper limit number, the creation of a new request command triggered by a request command from the LAN is stopped, and when the command consumption number on the WAN side is lower than the upper limit number, Create a request command. As a result, a response to the subsequent request command caused by the fact that the subsequent request command received from the LAN is not transferred to the WAN side until all the newly generated request commands are transferred to the WAN after the new request is created too much. Time degradation can be prevented.

FIG. 18 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 19 is a flowchart of processing performed by the relay device of this embodiment.

For example, when the client terminal 701 transmits a file open request, the server 702 returns a response. The relay apparatus 200 transmits a request for prefetching a file to the server 702 using a response to the file open request as a trigger.

In a state where the number of commands consumed on the WAN side is equal to the upper limit number (1802), the relay apparatus 200 waits for transmission of a response command to the client terminal 701 as a trigger for generating a new request command (step 2901). In this state, the relay apparatus 200 receives the response command (A) 1800 from the server 702, transmits it as the response command (A) 1801 to the client terminal 701 on the LAN side, and then receives the request command (B) 1803.

Upon receiving the request command (B) 1803, the request reception processing unit 112 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 2902), and if the command consumption number on the WAN side is equal to the upper limit number, The reading of the request command (B) 1803 stored in the reception buffer 111 is stopped.

On the other hand, when receiving the response command (A) 1800 from the server 702, the response reception processing unit 123 reduces the number of commands consumed on the WAN side by one. For this reason, since the number of commands consumed on the WAN side is smaller than the upper limit number (step 2902), the response transmission processing unit 113 can transmit the response command (A) 1801 toward the LAN side. That is, when the command consumption number on the WAN side is smaller than the upper limit number, the response transmission processing unit 113 transfers the response command (A) 1801 to the request creation unit 114 (step 2903).

The request creation unit 114 generates a plurality of new request commands (a-1) 1806, (a-2) 1808, and (a-3) 1810 based on the response command (A) 1801 (step 2904). Furthermore, the request creation unit 114 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 2905), and if the command consumption number on the WAN side is smaller than the upper limit number, the new request command (a-1) 1806 Is transferred to the request transmission processing unit 121 (step 2906).

The request transmission processing unit 121 transmits the transferred new request command (a-1) 1806 to the WAN. As a result, the number of commands consumed on the WAN side increases by one and becomes equal to the upper limit number.

Thereafter, the request transmission processing unit 121 determines whether there is a new request command that has not been transmitted (step 2907), and since the two newly generated request commands have not been transmitted, the command consumption number on the WAN side is again the upper limit number. (Step 2905). The request transmission processing unit 121 stops transfer of the newly generated request command to the request transmission processing unit 121 and waits until the command consumption number on the WAN side becomes smaller than the upper limit number.

Thereafter, when the relay apparatus 200 receives the response command 1807 from the server 702 and the number of commands consumed on the WAN side becomes one smaller than the upper limit number, a request command (a-2) 1808, which is one of newly created request commands, is obtained. It is transferred to the request transmission processing unit 121 (step 2906).

When the request transmission processing unit 121 transmits the request command (a-2) 1808 to the WAN, the number of commands consumed on the WAN side increases by one, and again the number of commands consumed on the WAN side becomes equal to the upper limit number.

The request transmission processing unit 121 determines whether there is a new request command that has not been transmitted (step 2907). Since one newly generated request command has not been transmitted, the command consumption number on the WAN side is again equal to the upper limit number. Is determined (step 2905). The request transmission processing unit 121 stops transmission of a newly generated request command and waits until the command consumption number on the WAN side becomes smaller than the upper limit number.

After that, when the relay apparatus 200 receives the response command 1809 from the server 702 and the number of commands consumed on the WAN side becomes smaller than the upper limit number, the request command (a-3) 1810 which is the last one of the newly created request command is It is transferred to the request transmission processing unit 121 (step 2906).

When the request transmission processing unit 121 transmits the request command (a-3) 1810 to the WAN, the number of commands consumed on the WAN side increases by one, and again the number of commands consumed on the WAN side becomes equal to the upper limit number.

The request transmission processing unit 121 determines whether there is a new request that has not been transmitted (step 2907), and when there is no new request command, the transmission of the new request triggered by the transmission response to the LAN side ends.

Thereafter, when the relay apparatus 200 receives the response command 1812 from the server 702, the number of commands consumed on the WAN side becomes smaller than the upper limit number. For this reason, the request reception processing unit 112 reads the request command (B) 1803 from the reception buffer 111 and transfers it to the request transmission processing unit 121, and the request transmission processing unit 121 transmits the request command (B) 1813 to the WAN side. .

As described above, when the WAN command consumption number is equal to the upper limit number, transfer of the newly generated request command to the WAN is triggered by the response command transmitted to the LAN, and the WAN command consumption number is the upper limit number. If it is smaller, the request command is transferred. As a result, it is possible to prevent the occurrence of an error and the forced disconnection of the connection due to the command consumption number on the WAN side being larger than the upper limit number, and to prevent the performance deterioration due to the communication delay between the client terminal and the server.

On the other hand, in the above-described embodiment, the subsequent request command received from the LAN side is not transferred to the WAN side until all new commands generated using a request command from the LAN as a trigger are transferred to the WAN, and the command response time There is a problem that deteriorates.

FIG. 20 is a sequence diagram of processing performed by the relay device of this embodiment. FIG. 21 is a flowchart of processing performed by the relay device of this embodiment.

In the state where the command consumption number on the WAN side is equal to the upper limit number (1902), the relay device 200 is waiting for transmission of a response command to the client terminal 701 as a trigger for generating a new request command (step 3001). In this state, the relay apparatus 200 receives the response command (A) 1900 from the server 702, transmits the response command (A) 1901 to the client terminal 701 on the LAN side, and then receives the request command (B) 1903. It was.

Upon reception of the request command (B) 1903, the request reception processing unit 112 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 3002), and if the command consumption number on the WAN side is equal to the upper limit number, The reading of the request command (B) 1803 stored in the reception buffer 111 is stopped.

On the other hand, when receiving the response command (A) 1900 from the server 702, the response reception processing unit 123 reduces the number of commands consumed on the WAN side by one. For this reason, since the number of commands consumed on the WAN side is smaller than the upper limit number (step 3002), the response transmission processing unit 113 can transmit the response command (A) 1901 toward the LAN side. That is, when the command consumption number on the WAN side is smaller than the upper limit number, the response transmission processing unit 113 transmits the response command (A) 1901 toward the LAN side (step 3001), and then the command consumption number on the WAN side is upper limit. It is determined whether it is equal to the number (step 3002). When the command consumption number on the WAN side is smaller than the upper limit number, the response transmission processing unit 113 transfers the response command (A) 1901 to the request creation unit 114 (step 3003).

Upon receiving the response command A 1901, the request creation unit 114 determines whether there is a request to be newly created using the response command (A) 1901 as a trigger (step 3004). As a result, when there is a request to be newly generated, the request creation unit 114 newly creates one request command (a) 1906 (step 3005).

The request creation unit 114 transfers the newly created request command (a) 1906 to the request transmission processing unit 121 (step 3006). The request transmission processing unit 121 transmits a new request command (a) 1906 to the WAN.

Thereafter, the request creation unit 114 determines whether the command consumption number on the WAN side is equal to the upper limit number (step 3007). If the command consumption number on the WAN side becomes smaller than the upper limit number, is there a request to be newly created? Is determined (step 3004). As a result, if there is an uncreated new request, a new request command is created again (step 3005). On the other hand, when the command consumption number on the WAN side is equal to the upper limit number, the creation of a new request command using the response command (A) 1901 as a trigger ends.

Thereafter, when the response reception processing unit 123 receives the response command 1907 in a state where the command consumption number on the WAN side is equal to the upper limit number (1904), the command consumption number on the WAN side becomes one smaller than the upper limit value. When the command consumption number on the WAN side becomes smaller than the upper limit number, the request reception processing unit 112 reads the request command (B) 1903 from the reception buffer 111 and transfers it to the request transmission processing unit 121. The request transmission processing unit 121 transmits a request command (B) 1903 as a request command (B) 1908 to the WAN.

In this way, when the number of commands consumed on the WAN side is equal to the upper limit number, generation of a new request command triggered by a response command transmitted to the LAN is stopped, and when the number of commands consumed on the WAN side is smaller than the upper limit number Generate a new request command. As a result, new request commands to be transmitted to the WAN side are created too much, and subsequent request commands received from the LAN are not transferred to the WAN side until all newly created request commands are transferred to the WAN. Deterioration of the response time of subsequent request commands can be prevented.

As shown in the seven examples of the specific processing procedure of the relay device 200 described above and the effect to be realized, in this embodiment, the command consumption number between the relay device and the server is larger than the upper limit number. It is possible to prevent the occurrence of an error and the forced disconnection of the connection, and it is possible to prevent the performance deterioration due to the delay of the communication between the client terminal and the server.

Furthermore, on the client terminal side, even when the response of the response command to the request command is completed, the server side prevents the request command from being transmitted from occurring for a long period of time, Risk at the time of failure of the relay device can be reduced.

Furthermore, subsequent request commands received from the client terminal side cannot be transferred to the server side until the relay device has created too many new requests to be sent to the server side and all the created new requests have been transferred to the server side. In addition, it is possible to prevent the response time from deteriorating.

The present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the scope of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to those having all the configurations described. A part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Moreover, you may add the structure of another Example to the structure of a certain Example. In addition, for a part of the configuration of each embodiment, another configuration may be added, deleted, or replaced.

In addition, each of the above-described configurations, functions, processing units, processing means, etc. may be realized in hardware by designing a part or all of them, for example, with an integrated circuit, and the processor realizes each function. It may be realized by software by interpreting and executing the program to be executed.

Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, a hard disk, and an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, and a DVD.

Also, the control lines and information lines indicate what is considered necessary for the explanation, and do not necessarily indicate all control lines and information lines necessary for mounting. In practice, it can be considered that almost all the components are connected to each other.

Claims

In a communication device that transfers commands between a server and a client terminal,
Managing the upper limit number and consumption number of commands exchanged between the server and the client terminal;
At least one of the consumption number and the upper limit number of commands exchanged between the communication device and the server, and the consumption number and upper limit number of commands exchanged between the communication device and the client terminal. Compare and
A communication apparatus that controls transfer of a command between the server and the client terminal based on at least one of the comparison results.
The communication device according to claim 1,
A control unit that controls transfer of a command between the communication device and the client terminal; and
A command number management unit for managing the upper limit number and consumption number of commands exchanged between the communication device and the server;
The controller is
If the consumed number of commands exchanged between the communication device and the server is equal to the upper limit number, processing of the command received from the client terminal is stopped,
A communication device, which processes a command received from the client terminal when the number of commands exchanged between the communication device and the server is smaller than an upper limit number.
The communication device according to claim 2,
A buffer for storing the command;
The controller is
If the consumed number of commands exchanged between the communication device and the server is equal to the upper limit number, the command received from the client terminal is stored in the buffer,
The communication apparatus, wherein when the number of consumed commands exchanged between the communication apparatus and the server is smaller than the upper limit number, the command stored in the buffer is read and the read command is processed.
The communication device according to claim 1,
A control unit that controls transfer of a command between the communication device and the server; and
A command number management unit for managing the upper limit number and consumption number of commands exchanged between the communication device and the server;
The controller is
If the consumed number of commands exchanged between the communication device and the server is equal to the upper limit number, stop sending the command to the server,
A communication device, wherein a command is transmitted to the server when the number of consumed commands exchanged between the communication device and the server is smaller than an upper limit number.
The communication device according to claim 1,
A control unit that controls transfer of a command between the communication device and the client terminal; and
A command number management unit for managing the upper limit number and consumption number of commands exchanged between the communication device and the client terminal;
The controller is
If the consumed number of commands exchanged between the communication device and the client terminal is equal to the upper limit number, the processing of the command received from the client terminal is stopped,
A communication apparatus that processes a command received from the client terminal when a consumed number of commands exchanged between the communication apparatus and the client terminal is smaller than an upper limit number.
The communication device according to claim 5, wherein
A buffer for storing the command;
The controller is
If the consumed number of commands exchanged between the communication device and the client terminal is equal to the upper limit number, the command received from the client terminal is stored in the buffer,
The communication device, wherein when the number of consumed commands exchanged between the communication device and the client terminal is smaller than the upper limit number, the command stored in the buffer is read and the read command is processed.
The communication device according to claim 1,
A control unit that controls transfer of a command between the communication device and the client terminal; and
A command number management unit for managing the upper limit number and consumption number of commands exchanged between the communication device and the server;
The controller is
If the consumption number of commands exchanged between the communication device and the server is equal to the upper limit number, stop creating the command to be sent to the server,
A communication apparatus that creates a command to be transmitted to the server when the number of consumed commands exchanged between the communication apparatus and the server is smaller than an upper limit number.
The communication device according to claim 7,
When the number of commands exchanged between the communication device and the server is smaller than the upper limit number, the control unit triggers reception of a command from the client terminal and sends a command to the server. A communication device characterized by being created.
The communication device according to claim 7,
When the number of commands exchanged between the communication device and the server is smaller than the upper limit number, the control unit triggers transmission of a command to the client terminal and sends a command to the server. A communication device characterized by being created.
The communication device according to claim 7,
The control unit sends a command to the client terminal triggered by reception of the command from the client terminal when the number of commands exchanged between the communication device and the server is smaller than the upper limit number A communication apparatus characterized by creating
The communication device according to claim 1,
Commands for managing the upper limit number and consumption number of commands exchanged between the communication device and the server, and the upper limit number and consumption number of commands exchanged between the communication device and the client terminal Number management department, and
A control unit for changing the upper limit number and consumption number of commands managed by the command number management unit;
The controller is
When receiving a command from the client terminal, increase the consumption number of commands on the client terminal side managed by the command number management unit,
When sending a command to the client terminal, decrease the number of client terminal side commands managed by the command number management unit, increase or decrease the upper limit number of the client terminal side commands,
When sending a command to the server, increase the number of server side command consumption managed by the command number management unit,
When receiving a command from the server, the communication apparatus is characterized in that the number of server side commands managed by the command number management unit is decreased and the upper limit number of the server side commands is increased or decreased.
The communication device according to claim 11,
When the control unit transmits a command to the client terminal, the difference between the upper limit number of the server side command and the consumption number and the difference between the upper limit number of the client terminal side command and the consumption number match. A communication apparatus, wherein an upper limit number of the commands is changed.
A method for managing the upper limit number and consumption number of commands exchanged between a server and a client terminal, and transferring the command in a communication device for transferring the command,
At least the number of commands consumed and the upper limit number exchanged between the communication device and the server, and the number of commands consumed and the upper limit number exchanged between the communication device and the client terminal Compare one and
A command transfer method comprising controlling transfer of a command between the server and the client terminal based on the at least one comparison result.
The command transfer method according to claim 13,
The communication device manages a control unit that controls command transfer between the communication device and the client terminal, and manages an upper limit number and a consumption number of commands exchanged between the communication device and the server. A command number management unit
The method
If the consumption number of commands exchanged between the communication device and the server is equal to the upper limit number, the control unit stops processing the command received from the client terminal,
A command transfer method, wherein when the number of commands exchanged between the communication device and the server is smaller than an upper limit number, the control unit processes a command received from the client terminal.
The command transfer method according to claim 14, wherein
The communication device includes a buffer for storing the command,
The method
If the consumption number of commands exchanged between the communication device and the server is equal to the upper limit number, the control unit stores the command received from the client terminal in the buffer,
When the number of commands exchanged between the communication device and the server is less than the upper limit number, the control unit reads the command stored in the buffer and processes the read command. Command transfer method.