JP2012070293A - Duplex communication method and device with high reliability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize duplex communication by an existing special system or a general-purpose communication application without remodelling and upgrading an existing communication control system, an OS and a communication layer.SOLUTION: A message of a general-purpose communication application is duplicated by a virtual network interface, a duplex communication control daemon and a duplex communication middleware, and the same message is transferred to the different network.

Description

  The present invention relates to a method for improving communication reliability later in a network communication system.

  As a method of making the network highly reliable, there is a method of duplicating the network. This duplication is broadly divided into a standby system in which the other network is operated when one network failure occurs and a system in which the same communication message is always transferred in both networks.

  In addition, the mounting methods are roughly classified into those controlled by hardware which is a network device other than the communication host and those controlled by software provided in the communication host itself.

  When controlled by a network device other than the communication host, the communication host does not need to control the network and does not need to be aware of duplex communication. This is advantageous in that it does not require modification of the communication host, but it is necessary to develop network hardware for duplication. In general, such a network is more expensive than an ordinary network, and the operation cost is also high. There is a tendency to be higher. Such network duplication by hardware is often employed in mission critical systems such as finance and military.

  Compared to this, in the communication host, in order to duplicate the network in terms of software, it is necessary to develop a dedicated operating system (hereinafter referred to as OS) having the function from the beginning. Inexpensive OS applications distributed in the pan-market cannot be used. This is because a general-purpose OS communication application interface (hereinafter referred to as API) is not provided.

  As another method using communication middleware, there is a method using communication middleware. In the middleware, there is communication middleware “Nexus / Dlink” described in Non-Patent Document 1 as a system that always transfers the same communication message in both networks. The middleware uses a unique communication API by a communication application, so that one message is copied and transferred to two different networks on the transmitting side, and transferred from the two networks on the receiving side. By importing the first arrival message and discarding the second arrival message, a highly reliable communication environment in which the network is duplicated is provided. It is not possible to duplicate the communication of available applications.

  Therefore, conventionally, in order to enjoy the advantages of the duplex network, there is a problem that an expensive dedicated network must be prepared, or a dedicated communication application that operates with middleware on the dedicated OS or general-purpose OS must be developed. there were.

"NeXUS / Dlink Guide & Reference Software Manual"

  In the method of Non-Patent Document 1, as described above, a communication application that can enjoy high-reliability communication by duplication must always use a communication application interface provided by the middleware. It is not possible to use a communication application that is running on

  In addition, in an existing information control system that is generally known, it is difficult to subsequently duplicate a communication application of an existing dedicated system, and an electronic mail, a Web browser, other A general communication application cannot be duplexed later.

  In general, in order to make the information control system compatible with highly reliable communication, it is inevitable to modify the communication layer of the existing OS.

  In view of the above problems, the present invention provides a method capable of duplicating the communication of an existing dedicated system or general-purpose communication application without the need to modify or modify an existing communication control system, OS, or communication layer. For the purpose.

  A typical embodiment of the present invention that solves the above problems will be described below.

  An apparatus for realizing the duplex highly reliable communication method of the present invention includes a virtual network interface, a duplex communication control daemon, and a duplex communication middleware.

  The virtual network interface of the communication device on the message transmission side always operates from the communication layer 2 to the application layer without creating the communication application message as a communication layer 2 message and then sending the message to the network. Transfer to the duplex communication control daemon. The duplex communication control daemon behaves as one application described by the API of the duplex communication middleware, and creates two messages of the communication layer 2 via the duplex communication middleware and transfers them to two different networks.

  On the other hand, the duplex communication middleware of the communication device on the message transmission side takes only the first arrival message out of the two messages transferred from the two networks, discards the later arrival message, and duplicates only the first arrival message. Forward to.

  The duplex communication control daemon transfers the message in the opposite direction to that described above. That is, the received message is transferred to the virtual network interface of the communication layer 2 this time, and the virtual network interface transfers the message to the communication application of the communication device on the message transmission side. Communication by the general-purpose communication application will be successful.

  In the present invention, only the communication layer 2 virtual network interface and the duplex communication control daemon are added, and these operate as applications that operate in the user space, so that the OS, communication layer, and communication application can be changed. Realize highly reliable duplex communication without modification or modification.

  According to the present invention, communication of a dedicated system or general-purpose communication application that is in operation is made highly reliable later without the need to modify or modify an existing communication control system, OS, or communication layer. be able to.

It is a figure explaining the system configuration in the present invention. It is a figure which shows the hardware constitutions of a communication apparatus. It is a figure which shows the software structure of a communication apparatus. It is a figure which shows the operation | movement outline | summary of duplex communication control middleware. It is a figure which shows the outline | summary of the reliable multiplex communication method of this invention. It is a flowchart which shows the process sequence of a duplex communication control daemon. It is a figure which shows the table required for this invention. It is a figure which shows the outline | summary of the reliable multiplex communication method of this invention provided with the hook library. It is a figure which shows the outline | summary of the multiplexing communication method.

(1) First Example In the following example, the communication AP 173 and the duplex communication management middleware 172 are software and operate in cooperation with the CPU 102. The description of this operation is omitted below. To do.

  The communication message is processed in an area stored as a communication buffer on the memory 104, and all or part of the communication message moves between the memory 104, the CPU 102, and the NIC 112 via the bus 110. Shall.

  FIG. 1 is a diagram illustrating a system configuration according to the present invention.

  The communication devices 1-1 to 1-2 are connected to local area networks (hereinafter referred to as LAN) 10-1, 10-2, and the communication device 2-1 is connected to LANs 20-1, 20-2. ing. The LANs 10-1 and 20-1 are connected to a wide area network (hereinafter referred to as WAN) 30-1, and the LANs 10-2 and 20-2 are connected to the WAN 30-2.

  FIG. 2 is a diagram illustrating a hardware configuration of the communication apparatuses 1-1, 1-2, and 2-1.

  Network interface cards (hereinafter referred to as NICs) 112-1 and 112-2, CPU 102, memory 104, input / output controller 106 for controlling keyboard 22 and mouse 24, and monitor controller 108 are connected by bus 110. The NICs 112-1 and 112-2 are connected to the LANs 10-1 and 10-2 described above.

  FIG. 3 is a diagram showing a configuration of software stored in the memory 104 of the communication apparatuses 1-1, 1-2, and 2-1.

  A NIC control driver 174 for controlling the NIC 112, a duplex communication management middleware 172 for transferring a message to a designated device via the network 10, and an input / output device control driver 150 for controlling the monitor 14, the keyboard 22 and the mouse 24. Is stored in the memory 104 of the communication device 1-1, 1-2, 2-1.

  The virtual NIC control driver 175 is a driver that performs control management of the virtual NIC 175 inside the communication apparatus.

  The virtual NIC 175 is a mechanism that emulates a network device such as a general network card using software virtualization technology, or software that is implemented by the mechanism.

  The virtual NIC 175 is also called a virtual interface, and the OS and communication application recognize and handle a virtual LAN card in the same manner as a LAN card mounted on a physical computer.

  Originally, an OS in a machine that does not have a physical interface recognizes that it has a physical LAN card, and tries to communicate with the physical LAN card. Actually, communication with the virtual LAN card is performed by software, but the OS can communicate with the duplex communication control daemon 176 by trapping the communication contents.

  In this embodiment, it is assumed that the communication application (hereinafter referred to as AP) 148 includes a socket communication interface (hereinafter referred to as socket API) for performing UDP / TCP / IP communication as a communication means. The communication means of the AP 148 is not limited to the socket API. Communication between the AP 148 and the duplex communication control daemon 176 is performed via the transmission queue 166, the reception queue 170, the NIC, or the virtual NIC 175.

  FIG. 4 is a diagram showing an outline of the operation of the duplex communication management middleware 172.

  The duplex communication management middleware 172 provides a unique communication AP interface (hereinafter referred to as API). The communication AP 173 provided with the AP performs communication between the communication APs.

  When the communication AP 173 transmits a message using the API, the duplication communication management middleware 172 of the transmission source creates a copy of the message, passes through a different NIC using a common communication protocol, and passes through the NIC of the communication partner. To deliver the message. TCP / UDP / IP is a well-known communication protocol, and this is used in this embodiment, but the communication protocol that can be used in this embodiment is not limited to this.

  The duplex communication management middleware 172 of the transmission destination captures only the first arrival message, delivers the first arrival message to the transmission destination communication AP, and discards the second arrival message. The determination of the first arrival or the second arrival is realized by the middleware assigning a serial number to the message. The serial number will be described later.

  By transmitting the same message to different networks in this way, even if a failure occurs in one network, communication is continued without interruption, and as a result, communication reliability is improved.

  An example of the duplex communication management middleware 172 is Hitachi's NeXUS / Dlink. In the following, the embodiment will be described on the premise of NeXUS / Dlink.

  FIG. 5 is a diagram showing an outline of the highly reliable multiplexed communication method of the present invention.

  Processing for transferring a message from the communication device 1-1 to the communication device 1-2 will be described in order.

  The communication AP software 148 of the communication device 1-1 transfers the message to the virtual NIC 175. The mode of the message is shown in (B) and (C) of FIG. The virtual NIC 175 transfers a message similar to the message transferred by the normal NIC to the network (the message mode is (C) in FIG. 5A) to the duplex communication control daemon 176 without flowing to the network.

  The duplexed communication control daemon 176 of the communication device 1-1 has a unique API provided by the duplexed communication management middleware 172, reads the destination address included in the message transferred from the virtual NIC 175, and reads the address Is converted into an appropriate transaction code (hereinafter referred to as TCD), and then a message is transmitted through the API. This conversion method will be described later.

  A transaction means a process or transaction related to a product, service, real-time event, etc., and is a concept different from an address. The TCD is a code for identifying a transaction. When data is transferred by designating the TCD, a communication device that has registered the TCD can receive a message.

  TCD is described in detail in Non-Patent Document 1.

When the duplex communication control daemon 176 of the communication device 1-1 transmits a message using the API, the duplex communication management middleware 172 of the communication device 1-1 creates a copy of the message. At this time, the same serial numbers are assigned to both the header portions NX_H (0) and NX_H (1) in FIG. This number is a continuous integer and can give a sufficiently large value. When the maximum value is exceeded, assignment of serial numbers starts again from 0 ((E-0) (E-1) in FIG. 5 (1)).
These messages are transferred to the corresponding communication partner NIC via separate NICs using the communication protocol of the general-purpose OS. The message is given a header via each communication layer of the general-purpose OS ((F-0) (F-1) to (H-0) (H-1) in FIG. 5A).

  The destination communication device 1-2 removes the header at the timing of passing through each communication layer, and the duplex communication management middleware 172 describes the header portions NX_H (0) and NX_H (1) in FIG. The serial number is checked, only the first message is fetched from the two messages, the message is sent to the duplex communication control daemon 176, and the last message is discarded.

  The duplex communication control daemon 176 of the transmission destination communication device 1-2 transfers the message to the virtual NIC 175, and the virtual NIC 175 communicates with the communication AP 148 of the transmission destination communication device 1-2 via the protocol layer in the same way as a normal NIC. Forward messages to

  Thus, not only a communication AP having a unique API of the duplex communication management middleware 172 but also a general-purpose communication AP, a virtual NIC and a user can be connected via a communication device such as an existing communication device. By simply installing the duplex communication control daemon 176 that operates in space later, it is possible to enjoy the benefits of duplex communication without any change in the OS or communication layer.

  FIG. 6 is a flowchart showing the processing procedure of the duplex communication control daemon 176.

  The duplex communication control daemon 176 obtains the IP address and subnet address assigned to the current NIC from the information of the two NICs included in the communication device 1-1. (Step 176-2).

  Here, “19.16.1.1/255.255.255.0” is acquired as the first NIC of the communication device 1-1, and “19.16.2.1/255” is acquired as the second NIC. .255.255.0 "is acquired. Here, the addresses of the first NIC and the second NIC are compared, the lower value of the network number is compared, and the value obtained by adding 1 to the larger value is used as the network address of the virtual NIC. The same number as the host address of the first NIC is set as the host address of the virtual NIC (“19.16.1.3/255.255.255.0”).

  Next, a reception handle for the communication apparatus is created (step 176-4).

  Here, the handle is a kind of identifier in which all information necessary for communication is described, and the communication application performs communication using the handle number. The communication AP need not be aware of the communication mode. The transmission handle is recognized as “data exit” and the reception handle is recognized as “data entry”.

  Here, the addresses of the first NIC and the second NIC are compared, the smaller number corresponding to the host number is TCD (# 1), and the lower value of the network number of the virtual NIC is The smaller value is set as a data field (hereinafter referred to as DF) number (# 3).

  Here, the DF means a place where data can be shared among a plurality of communication devices through which data flows, and is generally set in units of network segments designated by one network address. .

  Next, all communication device information of DF is obtained (176-6).

  This is to create the table in Table 7-1, and information on other communication devices may be obtained using the function of the duplex communication control middleware. In the case of NeXUS / Dlink, these pieces of information can be obtained with a command of nx_get_dfstat. The duplex communication control daemon 176 creates Table 7-1 using these pieces of information.

  Next, a transmission handle for another communication device is created (176-8, Table 7-5).

  The DF and TCD are determined by using the same method as described above, and the destination TCD is uniquely determined in the system.

  Table 7-5 can be used to convert from IP address to TCD. For example, the transmission handle for the communication device whose virtual NIC address is “19.16.3.2/255.255.255.0” is the DF number # 3 and the reception TCD # 2.

  Next, transmission handles for all communication devices in the DF are created (176-8) (Tables 7-2 and G-3). Transmission for all communication devices in the DF is realized by using a common UDP port number for each communication device.

  Here, the number obtained by adding the DF number to 50000 is used as the UDP port number (# 50003).

  As described above, by providing a configuration characterized in that message transfer is performed between the virtual network interface and the duplex communication control daemon, the effect of duplex communication can be achieved even in the general-purpose communication AP of the general-purpose OS. become.

(2) Second Example In the first example, the network configured by the virtual NIC is recognized as a network different from the network configured by the NIC.

  However, in this case, it is necessary to change the IP address for the communication AP. If an incorrect IP address is assigned, communication may not be possible.

  In order to cope with this case, in the second embodiment, a method for realizing the duplex communication method of the present invention without changing the IP address of the communication AP will be described.

  FIG. 8 is a diagram newly including a hook library 178 for hooking a communication API in addition to the virtual NIC 175 and the duplex communication control daemon 176 for realizing the duplex communication method of the present invention. The hook library 178 reads a transmission destination address included in a message passed from the application to the API before starting the communication API, and performs address conversion based on the conversion table in Table I. Table I is a subset of Table 7-1.

  For example, when the destination address of the message received in the transmission API is “19.16.1.2/255.255.255.0”, this is changed to “19.16.3.2/255.255.255.0”. To "". By converting in this way, the message is transferred to the virtual NIC without being transferred to the NIC 112-1, and is transferred from the virtual NIC to the duplex communication control daemon 176.

  On the other hand, when the source address of the message received in the transmission API is “19.16.3.2/255.255.255.0”, the source address is “19.1.1. .2 / 255.255.255.0 "and passing it to the communication AP 148 is sufficient (FIG. 8 (1)).

  When the destination is a communication device that does not include the virtual NIC 175 and the duplex communication control daemon 176 of the present invention, the IP address, subnet address, virtual IP address, and subnet address are described in the conversion table entry in Table I. Therefore, the destination hook library 178 does not perform the conversion process ((2) in FIG. 8).

  In such a case, communication without using the virtual NIC is performed, and the communication AP can communicate using the present method without being aware of the use of the present invention if the duplex communication method of the present invention is already provided. If not, perform normal communication without using this method.

  As described above, the effect of duplex communication can be enjoyed without changing the IP address for the communication AP.

(3) Third Embodiment FIG. 9 is a diagram showing a method for realizing multiplexed communication of a network having a multiplexing degree of 2 or more, to which the present invention is applied.

  The message transferred from the communication AP 148 is transferred to the virtual NIC 175-1, and then transferred to the duplex communication control daemon 176-1. Further, the message of the duplex communication control daemon 176-1 is transferred to the duplex communication control daemon 176-2 and 176-3 via the two virtual NICs 176-2 and 176-3.

  The duplex communication control daemon 176-2 transfers the message to the NICs 112-1 and 112-2, and the duplex communication control daemon 176-3 transfers the message to the NICs 112-3 and 112-4. Thereby, quadruple message transmission can be realized. Similarly, message reception can be quadruplexed, and as a result, quadruple communication can be easily realized.

  In the first to third embodiments, an Ethernet NIC or the like is assumed as the NICs 112-1, 112-2, 112-3, and 112-4. However, the NIC 112-1 is replaced with the Ethernet NIC and 112-2. The same effect can be obtained by using communication NICs of different network media such as a wireless LAN NIC, 112-3 as a carrier company communication card, and 112-4 as a PLC (Power Line Communication) communication card. Those skilled in the art will appreciate. In addition, by using a heterogeneous network, a secondary effect of improving reliability can be obtained. Further, an arbitrary multiplexed communication environment can be created by further increasing the number of stages using the duplex communication control daemon.

1 Communication device 10 LAN
30 WAN
110 Bus 112 NIC
120 CPU
104 memory
22 Keyboard 24 Mouse
106 Input / output controller 108 Monitor controller 148 Communication AP
150 I / O device control driver 175 Virtual NIC
174 NIC control driver 175 Virtual NIC control driver 172 Duplex communication management middleware 176 Duplex communication control daemon 166 Transmission queue 170 Reception queue 180 Hook library

Claims (6)

A duplex high-reliability communication device for performing high-reliability communication between communication applications by connecting two physical interfaces to two networks and transferring the same message to the network,
A virtual network interface which is software for transferring messages via the physical interface, a duplex communication control daemon, and a duplex communication middleware;
When sending data,
The message transferred from the communication application is transferred to the virtual network interface, transferred from the virtual network interface to the duplex communication control daemon, and further duplicated into two or more messages by the duplex communication middleware. Forward the message from one physical network interface,
When receiving data,
Receive one or more messages from the two physical network interfaces,
The duplex communication middleware captures the first message among the messages transferred from the two physical network interface cards and discards the later message, thereby transferring only the first message to the duplex communication control daemon. And
The duplex communication control daemon transfers the first-arrival message to the virtual network interface,
The virtual network interface transfers the first-arrival message to a communication application. The duplex highly reliable communication device according to claim 1,
When sending data,
The source address or destination address of the physical network interface included in the message is converted into the source address or destination address of the virtual network interface,
When receiving data,
Converting the source address or destination address of the virtual network interface included in the message into the source address or destination address of the physical network interface;
A duplex highly reliable communication device characterized by that. A multiplexed high-reliability communication apparatus that performs high-reliability communication between communication applications by connecting two or more physical interfaces to two or more networks and transferring the same message to the networks,
Two or more virtual network interfaces that are software for transferring messages via the physical interface, two or more duplex communication control daemons, and duplex communication middleware,
When sending data,
The message transferred from the communication application is transferred to the virtual network interface, transferred from the virtual network interface to the multiplexed communication control daemon, and further duplicated into two or more messages by the duplex communication middleware. , By transferring to another multiplexing communication control daemon and repeating these processes, the message is transferred from the two or more physical network interfaces,
When receiving data,
Receive two or more messages from the two or more physical network interfaces,
The multiplexed communication middleware captures a first-arrival message from among the messages transferred from the two or more physical network interface cards, and discards the later-arrival message, whereby only the first-arrival message is sent to the duplex communication control daemon Forward to
The duplex communication control daemon transfers the first-arrival message to the virtual network interface, and the virtual network interface further transfers to another virtual network interface, and after repeating these processes, transfers to the communication application. A highly reliable multiplex communication device characterized by A duplex high-reliability communication method in which two physical interfaces are connected to two networks, respectively, and the same message is transferred to the network to perform highly reliable communication between communication applications.
A virtual network interface which is software for transferring messages via the physical interface, a duplex communication control daemon, and a duplex communication middleware;
When sending data,
The message transferred from the communication application is transferred to the virtual network interface, transferred from the virtual network interface to the duplex communication control daemon, and further duplicated into two or more messages by the duplex communication middleware. Forward the message from one physical network interface,
When receiving data,
Receive one or more messages from the two physical network interfaces,
The duplex communication middleware captures the first message among the messages transferred from the two physical network interface cards and discards the later message, thereby transferring only the first message to the duplex communication control daemon. And
The duplex communication control daemon transfers the first-arrival message to the virtual network interface,
The virtual network interface transfers the first-arrival message to a communication application. The duplex high-reliability communication system according to claim 4,
When sending data,
The source address or destination address of the physical network interface included in the message is converted into the source address or destination address of the virtual network interface,
When receiving data,
Converting the source address or destination address of the virtual network interface included in the message into the source address or destination address of the physical network interface;
Dual high-reliability communication system characterized by this. A multiplexed high-reliability communication system in which two or more physical interfaces are connected to two or more networks, and the same message is transferred to the networks to perform high-reliability communication between communication applications.
Two or more virtual network interfaces that are software for transferring messages via the physical interface, two or more duplex communication control daemons, and duplex communication middleware,
When sending data,
The message transferred from the communication application is transferred to the virtual network interface, transferred from the virtual network interface to the multiplexed communication control daemon, and further duplicated into two or more messages by the duplex communication middleware. , By transferring to another multiplexing communication control daemon and repeating these processes, the message is transferred from the two or more physical network interfaces,
When receiving data,
Receive two or more messages from the two or more physical network interfaces,
The multiplexed communication middleware captures a first-arrival message from among the messages transferred from the two or more physical network interface cards, and discards the later-arrival message, whereby only the first-arrival message is sent to the duplex communication control daemon Forward to
The duplex communication control daemon transfers the first-arrival message to the virtual network interface, and the virtual network interface further transfers to another virtual network interface, and after repeating these processes, transfers to the communication application. Multiplexed high-reliability communication system characterized by

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