JP2010246013A - Communication path switching apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication path switching apparatus and method, in which the interruption of communication is made within a short time so as to be applicable to the communication requiring reliability and real-time property, with respect to redundant paths. <P>SOLUTION: A communication path switching apparatus 10 is installed between terminals exchanging data, while facing terminals of redundant two communication paths comprised of an active system 20 and a reserve system 21. The communication path switching apparatus includes a transmitter 11 for duplicating data and transmitting the duplicated data of the same contents to the communication path of the active system 20 and the communication path of the reserve system 21, respectively; and a receiver 12 for receiving first arrival data between data transmitted through the communication path of the active system and data transmitted through the communication path of the reserve system. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication path switching apparatus and method. In particular, the present invention relates to a communication path switching apparatus and method for shortening communication interruption at the time of failure.

  In an IP network, as a method for realizing redundancy of a communication path (hereinafter simply referred to as a path) between devices such as terminals and servers, that is, between end devices of an IP network, an STP (Spanning Tree) is used in a LAN (Local Area Network). Protocol), VRRP (Virtual Router Redundancy Protocol) in the default gateway, and WAN (Wide Area Network) in RIP (Routing Information Protocol) / OSPF (Open Shortest Path), etc. is there. However, these methods have a problem that it may take a long time from the occurrence of a failure to the end of the path switching.

  To solve this problem, we propose a device that monitors the presence / absence of a failure by sending / receiving response signals to multiple routes and selects the route to be used from the multiple routes based on the result. (Patent Document 1).

JP 2005-94137 A

  In the apparatus described in Patent Document 1, in order to reliably determine the occurrence of a failure, if even one response packet for failure monitoring cannot be received, it is not immediately determined that a failure has occurred, but only the set number of packets. It is determined that a failure has occurred when continuous reception has failed. Therefore, there is a limit to shortening the time required from failure occurrence to path switching, and it can be applied to communications that require reliability and real-time performance (delay time, packet loss, etc.) such as monitoring control information in power system operation. It can be difficult.

  On the other hand, it can also be applied to communications that require reliability and real-time performance. As another method for solving the conventional problem that it takes a long time from the occurrence of a failure to the end of path switching, MPLS (Multi Protocol Label Switching) or the like is available. There are a method of introducing a high-spec network device that supports the function, and a method of customizing and incorporating a dedicated function into the system itself (application, middleware, etc.) of the terminal / server. However, these methods have a problem that they lack general versatility and are inefficient.

  It is an object of the present invention to provide a communication path switching apparatus and method for shortening communication interruption in a path made redundant by a conventional method to such an extent that it can be applied to communications that require reliability and real-time characteristics. Objective. It is another object of the present invention to provide a communication path switching apparatus and method that is versatile and efficient.

  (1) A communication path switching apparatus installed opposite to the ends of a plurality of redundant communication paths between apparatuses performing data transmission / reception, wherein the data is replicated and replicated to each of the plurality of communication paths A communication path switching apparatus comprising: a transmission unit that transmits data having the same content; and a reception unit that receives data that has arrived first among data transmitted through the plurality of communication paths.

  According to the configuration of (1), the communication path switching device installed opposite to the ends of a plurality of redundant communication paths between devices that transmit and receive data replicates data, and each of the plurality of communication paths A transmitting unit that transmits each of the duplicated data having the same content; and a receiving unit that receives data that has arrived first among the data transmitted through each of the plurality of communication paths. Here, a plurality of redundant communication paths refers to a plurality of communication paths that are the same at both ends and have different intermediate paths.

  As a result, when the communication path switching device is installed opposite to the end of the communication path, data is transmitted to the receiving side through each of the plurality of redundant communication paths. Even data can arrive at the receiver. As a result, when a failure occurs, data arrives at the receiving side without switching the path, so that the communication disruption should be short enough to be applicable to communications that require reliability and real-time characteristics. Can do.

  (2) The transmission unit assigns the same identifier to each of the duplicated data having the same content, and the reception unit, based on the identifier, whether the arrived data has the same content as the data that has already arrived. The communication path switching device according to (1), which determines whether or not.

  According to the configuration of (2), the transmission unit of the communication path switching device gives the same identifier to each of the duplicated data having the same content, and the reception unit of the communication path switching device has arrived based on the identifier It is determined whether the data has the same content as the data that has already arrived.

  As a result, a plurality of data of the same content arrives at the receiving unit through at least the first route and the second route, but the receiving unit has already arrived at the identifier given to the data at the transmitting unit. It is possible to determine whether or not the content is the same as the processed data. That is, the receiving unit can determine data having the same content among a plurality of data transmitted through at least the first route and the second route.

  (3) The communication path switching device according to (1) or (2), wherein the receiving unit discards data that arrives later.

  According to the configuration of (3), the receiving unit of the communication path switching device discards data that arrives later. As a result, the receiving unit of the communication path switching device receives the data that has arrived first and discards the data that has arrived later, so that the device that receives the data connected to the communication path switching device can only receive one data. Can be received.

  (4) An installed communication path switching method including a communication path switching apparatus installed facing opposite ends of a plurality of redundant communication paths between apparatuses performing data transmission / reception, wherein the data is duplicated, Communication path switching comprising: transmitting each piece of data having the same content copied to each communication path; and receiving the data that arrives first among the data transmitted through each of the plurality of communication paths Method.

  According to the present invention, there is provided a communication path switching apparatus and method for shortening communication interruption in a path made redundant by a conventional method to such an extent that it can be applied to communications that require reliability and real-time characteristics. be able to. Further, the communication path switching device and method are versatile and efficient.

It is a conceptual diagram which shows the communication system which concerns on this invention and a prior art. It is a figure which shows the function structure of the communication path switching apparatus which concerns on suitable embodiment of this invention. It is a flowchart of the transmission / reception process which concerns on suitable embodiment of this invention.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. This is merely an example, and the technical scope of the present invention is not limited to this.

[Communication system conceptual diagram]
FIG. 1 is a conceptual diagram showing a communication system according to the present invention and the prior art. FIG. 1A is a conceptual diagram showing a communication system using a communication path switching apparatus according to the present invention, and FIG. 1B is a conceptual diagram showing a communication system using a switch according to the prior art. First, the characteristics of the communication system using the switch according to the prior art shown in FIG. 1 (b) will be described, and then the communication path switching device according to the present invention shown in FIG. 1 (a) will be used in comparison with the prior art. The communication system that has been used will be described. Note that a terminal and a server are used as examples as devices for transmitting and receiving data.

  FIG. 1B shows a communication system between a terminal 40 and a server 41 having a path made redundant by a switch. In FIG. 1B, VRRP is used as the redundancy method, but this is an example, and other redundancy methods may be used, or a router or the like may be used instead of the switch.

  The terminal 40 is connected to the edge router 1-1 and the edge router 1-2 of the IP network 30 via the switch 100-1. Similarly, the server 41 is connected to the edge router 1-3 and the edge router 1-4 of the IP network 30 via the switch 100-2. The edge router 1-1 and the edge router 1-3 are connected, and similarly, the terminal router 40 and the server 41 can communicate with each other by connecting the edge router 1-2 and the edge router 1-4. ing. The route between the edge router 1-1 and the edge router 1-3 and the route between the edge router 1-2 and the edge router 1-4 are physically the same devices (routers) in the IP network. Etc.).

  It is assumed that there are two redundant paths in the communication system between the terminal 40 and the server 41, and that each is a normal system and a standby system. In the following description, it is assumed that the redundant paths are two paths, the normal system and the standby system. Here, a path between the edge router 1-1 and the edge router 1-3 is a normal system 20, and a path between the edge router 1-2 and the edge router 1-4 is a standby system 21. 1A and 1B, the backup system 21 has one path, but there may be a plurality of paths. However, when there are a plurality of routes of the standby system 21, they must be routes that do not go through physically the same device (router or the like) in the IP network.

  Here, a data transmission / reception method at the time of occurrence of a failure according to the prior art will be described taking data transmission from the terminal 40 to the server 41 as an example. During normal times, data is transmitted from the terminal 40 to the server 41 using the route of the service 20. However, when a failure occurs in the regular system 20, the terminal 40 switches the transmission destination (default gateway) to the edge router 1-2. Data transmission is performed using the route of the standby system 21. Thereby, the interruption of communication when a failure occurs can be shortened.

  In the method described in Patent Document 1, instead of a switch, a communication path switching device that can confirm whether or not a failure has occurred in a path by sending and receiving a response signal is used. Since the communication path switching device described in Patent Document 1 can detect a failure and switch a path in a short time, communication interruption when a failure occurs can be shortened compared to the above-described conventional technology. .

  FIG. 1A shows a communication system between a terminal 40 and a server 41 in which a communication path switching apparatus according to the present invention is installed facing the end of a redundant path. Portions that perform the same functions as those in FIG. 1B described above are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate.

  In FIG. 1A, a communication path switching device 10-1 is provided instead of the switch 100-1, and a communication path switching device 10-2 is provided instead of the switch 100-2. The data transmission from the terminal 40 to the server 41 will be described as an example. The communication path switching device uses both the path of the active system 20 and the path of the standby system 21 regardless of whether it is a normal time or a failure occurs. Data is transmitted from the terminal 40 to the server 41.

  As described above, in the prior art, data was transmitted / received using only the path of the normal system 20 at normal times. However, the communication path switching apparatus according to the present invention uses both the normal system 20 and the standby system 21. Send and receive data. Thereby, even if a failure occurs in the normal system 20, the data transmitted to the path of the standby system 21 can arrive at the communication path switching device on the receiving side. Further, when a failure occurs in the standby system 21, data transmitted to the path of the normal system 20 can arrive at the communication switching device on the receiving side.

  As a result, since data arrives at the receiving side without switching the path when a failure occurs, communication interruption when a failure occurs can be shortened compared to conventional technology, and communication interruption is reliable and real-time. The time can be shortened to such an extent that it can also be applied to communications requiring the above.

  Compared with the method described in Patent Document 1, it is not necessary to confirm whether or not a failure has occurred in the route, so communication interruption can be shortened more quickly, and communication interruption is reliable and real-time. The time can be shortened to such an extent that it can also be applied to communications requiring the above.

[Communication path switching device]
FIG. 2 is a diagram showing a functional configuration of the communication path switching apparatus according to the preferred embodiment of the present invention. The communication path switching device 10 includes a transmission unit 11 and a reception unit 12.

  The transmission unit 11 duplicates data received from the terminal 40. The transmission unit 11 replicates the data received from the terminal 40, and then transmits the data having the same content copied to the paths of the normal system 20 and the standby system 21, respectively. Note that the number of paths of the standby system 21 is not limited to one, and there may be a plurality of paths, but data is transmitted to all of the paths of the plurality of standby systems 21. Moreover, the data received from the original terminal 40 may be included in the duplicated data having the same content.

  In this way, even if a failure occurs in any of the routes by transmitting the data having the same content copied to each of the plurality of routes in the normal system 20 and the standby system 21, a route in which no failure has occurred The data can arrive at the receiving side. Further, when it is detected that a failure has occurred in the data transmission path, the data is transmitted to a plurality of paths of the normal system 20 and the standby system 21 in contrast to the conventional method of transmitting data by switching to a new path. Therefore, even if a failure occurs, there is no need to switch to a new route.

  As a result, the communication interruption at the time of failure can be shortened, so that the communication path switching device 10 can be applied to communications that require reliability and real-time performance.

  Further, after the data is duplicated, the transmission unit 11 assigns an identifier to each duplicated data having the same content. The identifier is given to data in order to determine the same data, and is composed of an arbitrary bit string.

  The receiving unit 12 receives the data that has arrived first among the data that has arrived at the receiving unit 12 via the paths of the normal system 20 and the standby system 21. When receiving the data, the receiving unit 12 transmits the data to the terminal 40. On the other hand, the receiving unit 12 discards data that arrives later. Whether the data arrives first or later is determined based on an identifier given to the data.

  Specifically, the receiving unit 12 determines whether or not the identifier given to the data is included in the identifier group held in the receiving unit 12. If the identifier assigned to the data is included in the identifier group, it is determined that the data is data that has arrived later, and the data is discarded. On the other hand, if the identifier assigned to the data is not included in the identifier group, it is determined that the data is data that has arrived first, and the data is received. At this time, the identifier of the received data is added to the identifier group held in the receiving unit 12. The reason why the received data identifiers are held in the receiving unit 12 as an identifier group is to determine data that arrives later as described above.

  In this way, the terminal 40 that receives data by discarding data other than the data that has arrived at the receiving unit 12 first among the data transmitted to each of the plurality of paths of the normal system 20 and the standby system 21. Does not receive multiple identical data.

[Transmission and reception processing]
FIG. 3 is a flowchart of data transmission / reception processing according to the preferred embodiment of the present invention. FIG. 3A is a flowchart of data transmission processing according to the preferred embodiment of the present invention. The process starts when the communication path switching apparatus 10 receives data transmitted from the terminal 40.
S10: The transmission unit 11 duplicates the data received from the terminal 40.
S20: The transmission unit 11 assigns the same identifier to each piece of data having the same content copied in step S10.
S30: The transmission unit 11 transmits the data to which the identifier is assigned in step S20 to each of the paths of the normal system 20 and the standby system 21.

FIG. 3B is a flowchart of data reception processing according to the preferred embodiment of the present invention.
S100: The receiving unit 12 receives arrival of data sent through the path of the normal system 20 or the standby system 21.
S110: The receiving unit 12 determines whether or not the identifier given to the data received in step S100 is included in the identifier group held by the receiving unit 12. If the determination result is YES, the process proceeds to step S120, and if the determination result is NO, the process proceeds to step S130.
S120: The receiving unit 12 discards the data received in step S100.
S130: The receiving unit 12 receives the data received in step S100.

DESCRIPTION OF SYMBOLS 10 Communication path switching device 11 Transmission part 12 Reception part 20 Regular system 21 Backup system

Claims (4)

A communication path switching device installed opposite to the ends of a plurality of redundant communication paths between devices that transmit and receive data,
A transmitter that replicates the data and transmits each of the same content data replicated to each of the plurality of communication paths;
Among the data transmitted through each of the plurality of communication paths, a receiving unit that receives data that has arrived first;
A communication path switching device comprising: The transmitter assigns the same identifier to each of the duplicated data having the same content,
The communication path switching apparatus according to claim 1, wherein the receiving unit determines whether the arrived data has the same content as the already arrived data based on the identifier.   The communication path switching apparatus according to claim 1, wherein the receiving unit discards data that arrives later. An installed communication path switching method including a communication path switching apparatus installed opposite to the ends of a plurality of redundant communication paths between devices performing data transmission and reception,
Replicating the data and transmitting each of the same content data copied to each of the plurality of communication paths;
Of the data transmitted through each of the plurality of communication paths, receiving the data that has arrived first;
Communication path switching method.

Images