JP3970741B2 - Data communication system and data communication control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data communication system that performs data communication between a plurality of communication devices via a communication path, and a data communication control device that controls data communication between the plurality of communication devices and is suitable for the data communication system.
[0002]
[Prior art]
Conventionally, xDSL systems such as an ADSL (Asymmetric Digital Subscriber Line) system and an SDSL (Symmetric Digital Subscriber Line) system have been developed.
The xDSL system can realize high-speed communication at low cost, but has a drawback of being vulnerable to noise because it uses a high frequency band.
[0003]
Normally, even if communication is maintained, the line speed is extremely reduced at unspecified time due to the power of the equipment that becomes the noise source being turned on or the start of communication by other communication methods and interference. Or the line may be disconnected.
For this reason, when used for communication requiring reliability, a means for securing a backup communication path is required.
Conventionally, for example, a method described in Patent Document 1 has been considered as a method for securing a backup communication path. As a result, it is possible to secure a backup communication path, and it is possible to prevent the occurrence of line disconnection due to interference.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-247191
[Problems to be solved by the invention]
However, in the method described in Patent Document 1, a failure or the like occurs by physically providing a plurality of communication paths and physically switching the communication paths between communication devices in order to secure a backup communication path. To bypass the communication path.
Therefore, since a plurality of physical communication paths are required, there is a problem that the system configuration becomes complicated and expensive.
[0006]
An object of the present invention is to ensure a bypass communication path with a simple and inexpensive configuration.
[0007]
[Means for Solving the Problems]
According to the present invention, in a data communication system that performs data communication between a plurality of communication devices using a physical communication path, communication of the first form is performed between the plurality of communication devices via the physical communication path. First communication means for performing, second communication means for performing communication of the second form between the plurality of communication devices via the physical communication path, and the first communication means for performing the first communication via the physical communication path. When a failure occurs in data communication between the plurality of communication devices performed by one communication unit, by switching from communication by the first communication unit to communication by the second communication unit, in a different communication mode There is provided a data communication system comprising communication control means for performing data communication between the plurality of communication devices via the same physical communication path.
When a failure occurs in data communication between a plurality of communication devices performed by the first communication unit via the physical communication path, the communication control unit performs the second communication from the communication by the first communication unit. By switching to communication by means, data communication is performed between the plurality of communication devices via the same physical communication path in different communication forms.
[0008]
According to the present invention, in the data communication control device that controls data communication performed between a plurality of communication devices using a physical communication path, the first communication is performed between the plurality of communication devices via the physical communication path. First communication means for performing communication in the form of the second communication means, second communication means for performing communication in the second form between the plurality of communication devices via the physical communication path, and the physical communication path. By switching from communication by the first communication means to communication by the second communication means when a failure occurs in data communication between the plurality of communication devices performed by the first communication means via There is provided a data communication control device comprising communication control means for performing data communication between the plurality of communication devices via the same physical communication path in different communication forms.
When a failure occurs in data communication between a plurality of communication devices performed by the first communication unit via the physical communication path, the communication control unit performs the second communication from the communication by the first communication unit. By switching to communication by means, data communication is performed between the plurality of communication devices via the same physical communication path in different communication forms.
[0009]
The first communication means may be an xDSL modem, and the second communication means may be an analog modem.
The first communication means may be an xDSL modem, and the second communication means may be a terminal adapter.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram of a data communication system and a data communication control apparatus according to the first embodiment of the present invention. In the first embodiment, an example is given in which communication by an ADSL (Asymmetric Digital Subscriber Line) modem that connects two specific points via the Internet is backed up by communication using an analog modem. .
[0011]
In FIG. 1, an ADSL router 2 as a data communication control device is a LAN interface unit as an interface means for transmitting and receiving IP (Internet Protocol) packets to and from a terminal (communication device) 1 in a LAN (Local Area Network). 3, a DSL (Digital Subscriber Line) splitter 8 connected to a subscriber line 9 having an ADSL service and capable of mixing and distributing a data signal and a voice signal, and an ADSL separated by the DSL splitter 8 ADSL modem 6 as a first communication means for performing ADSL line connection control using signal and transmission / reception of IP packets via ADSL line, and analog line connection control and analog using analog signal separated by DSL splitter 8 Second communication means for transmitting and receiving IP packets via a line The analog modem 7 and the ADSL modem 6 are monitored, the line connection / disconnection instruction is given to the analog modem 7, and the IP packet from the IP routing unit 4 is sent to the ADSL modem 6 or the analog modem 7. IP control as routing means for performing routing processing on the basis of a predetermined routing rule for the IP packet received from the LAN interface unit 3 and the line control part 5 Part 4.
[0012]
The subscriber line 9 is connected to a terminal (communication device) 13 via an analog telephone network 10, the Internet 11, and an ADSL router 12.
In FIG. 1, an ADSL router 2 is connected to the Internet 11 via a subscriber line 9 provided with an ADSL service, and has the same configuration as the ADSL router 2 between the terminal 13 and the ADSL router 12 connected to the LAN. Assume that IP packets are transmitted and received.
[0013]
It is assumed that a routing table for the ADSL router 12 and the terminal 13 is registered in advance in the ADSL router 2. Similarly, it is assumed that a routing table for the ADSL router 2 and the terminal 1 is registered in advance in the ADSL router 12.
In the DSL splitter 8 connected to the subscriber line 9, the analog signal of the subscriber line 9 is separated / mixed into a voice band and an ADSL signal band, the voice band is in the analog modem 7, and the ADSL signal band is in the ADSL modem 6. Supply.
[0014]
The ADSL modem 6 controls connection of the ADSL line and operates to keep the ADSL line in a steady connection state. The analog modem 7 performs analog line connection / disconnection control in response to an instruction from the line control unit 5.
The LAN interface unit 3 that has received the LAN frame including the IP packet from the terminal 1 extracts the IP packet from the LAN frame and passes it to the IP routing unit 4. The IP routing unit 4 refers to the destination address of the IP packet, and passes it to the line control unit 5 if it is addressed to the terminal 13.
[0015]
The line control unit 5 detects the line connection state of the ADSL modem 6 and passes the IP packet to the ADSL modem 6 if the ADSL line is connected. The IP packet sent from the ADSL modem 6 to the subscriber line 9 reaches the ADSL router 12 via the Internet 11 and is sent to the terminal 13 as registered in the routing table in the ADSL router 12.
[0016]
On the other hand, the IP packet sent from the terminal 13 to the terminal 1 reaches the ADSL modem 6 following the procedure reverse to the procedure described above, and is delivered to the line control unit 5. The line control unit 5 passes the IP packet to the IP routing unit 4, and the IP routing unit 4 refers to the destination address of the IP packet, confirms that it is addressed to the terminal 1, and passes it to the LAN interface unit 3. The LAN interface unit 3 encapsulates the IP packet in a LAN frame and passes it to the terminal 1.
The above is the procedure of IP packet communication performed in a normal state.
[0017]
Next, an operation for changing the communication state when the line connection cannot be maintained due to the occurrence of a path failure will be described.
The line control unit 5 constantly monitors the line connection status of the ADSL modem 6 and the arrival confirmation of the IP packet according to the Internet protocol. The line connection of the ADSL modem 6 cannot be performed due to a path failure, or the arrival confirmation of the IP packet is continuously performed. If it fails, an instruction for line connection is issued to the analog modem 7. The connection instruction includes the analog line telephone number of the ADSL router 12 registered in advance.
[0018]
After the line connection by the analog modem 7 is completed, the line control unit 5 passes the IP packet transferred from the IP routing unit 4 to the analog modem 7 and secures a communication path for the IP packet via the analog telephone network 10. . Similarly, when an incoming call is received from the ADSL router 12 to the analog modem 7, subsequent IP packets are transmitted / received via the analog modem 7.
[0019]
The line control unit 5 monitors the line connection state of the ADSL modem 6 while sending and receiving IP packets via the analog modem 7, and when the line is connected, the ICMP Echo Request packet (echo request) is sent to the ADSL router 12. Message).
The line control unit 5 determines that the communication path via the ADSL modem 6 has been restored when the response from the ADSL router 12 to the echo request message is confirmed (ICP echo reply packet: echo reply message). A command to disconnect the line is sent to the analog modem 7 and the IP packet transferred from the IP routing unit 4 is switched to be transferred to the ADSL modem 6.
[0020]
With the above operation, when a failure occurs in the communication path using the ADSL line between two specific points, it is possible to secure the communication path using the analog line.
Further, according to the first embodiment, a dedicated physical line is not required for securing a bypass communication path. Since xDSL communication uses a high frequency band, communication can be performed on the same physical line as other communication methods using a low frequency band. For example, ADSL communication and analog modem communication, VDSL communication and ISDN communication, and the like.
[0021]
On the other hand, since a high frequency band is used, it is easily affected by external factors such as noise, and an unexpected communication path may be interrupted. The present embodiment is not intended to relieve the failure of the line itself, and is intended to supplement xDSL communication with a slower but more stable communication method. Therefore, the line cost can be increased without using a detour communication line. It is possible to improve the reliability of communication while suppressing it.
In addition, it is easy to introduce and abolish the system. In the case of introducing the system, it is not necessary to prepare a new line, so that it can be used only by changing the contract contents of the existing line, and there is no need for wiring work. On the contrary, the same effect as described above can be obtained when the use of the system is stopped.
[0022]
FIG. 2 is a block diagram of a data communication system and a data communication control apparatus according to the second embodiment of the present invention, and the same reference numerals are given to the same parts as those in FIG.
2, the data communication system includes a terminal (communication device) 1, a VDSL (Very High Speed Digital Subscriber Line) router 22 as a data communication control device connected to the terminal 1, and a VDSL router 22 via a subscriber line 9. A configuration including an ISDN network 210 and the Internet 11 connected to each other, a VDSL router 212 connected to the ISDN network 210 and the Internet 11, and a terminal (communication device) 13 connected to the VDSL router 212. It is.
[0023]
The VDSL router 22 includes a LAN interface unit 3 as an interface unit, an IP routing unit 4 as a routing unit, a line control unit 5 as a communication control unit, a VDSL modem 26 as a first communication unit, and a second communication unit. Terminal adapter 27 and DSL splitter 8 as splitter means.
[0024]
The VDSL router 22 performs normal data communication with the VDSL modem 26. When a failure occurs in the VDSL communication, the terminal controller 27 controls connection with the ISDN line 210 and ISDN communication under the control of the line control unit 5. By doing so, a detour is formed. Since other operations are the same as those in FIG. 1, detailed description thereof is omitted. The second embodiment also has the same effect as the first embodiment.
[0025]
As described above, according to each of the above embodiments, the xDSL modem that performs the first form of communication (xDSL communication) between a plurality of communication apparatuses (terminals 1 and 13) via the physical communication path 9. 6, 26 and the analog modem 7 or terminal adapter 27 that performs the second type of communication (analog communication or ISDN communication) between the plurality of communication devices (terminals 1, 13) via the physical communication path 9. Communication by the xDSL adapters 6 and 26 when a failure occurs in data communication between the plurality of communication devices (terminals 1 and 13) performed by the xDSL adapters 6 and 26 via the physical communication path 9. By switching to communication by the analog modem 7 or the terminal adapter 27, the plurality of communication devices (terminals 1, 13 through the same physical communication path 9 in different communication forms). It is characterized in that it comprises a line control unit 5 which performs data communication with.
[0026]
That is, the line control unit 5 determines whether or not a failure has occurred in the data communication between the plurality of communication devices (terminals 1 and 13) performed by the xDSL adapters 6 and 26 via the physical communication path 9. When it is determined that a failure has occurred, the communication is switched from the communication using the xDSL adapters 6 and 26 to the communication using the analog modem 7 or the terminal adapter 27. When detecting whether or not a failure has occurred in data communication between the plurality of communication devices (terminals 1 and 13) performed by the xDSL adapter 6 or the like via the physical communication path 9, the line control unit 5 When the line connection state of the ADSL modem 6 and the arrival confirmation of the IP packet by the Internet protocol are constantly monitored, the line connection of the ADSL modem 6 cannot be performed due to a route failure, or the arrival confirmation of the IP packet continuously fails. May be configured to determine that a failure has occurred.
By adopting such a configuration, it is not necessary to prepare a plurality of physical lines, so that it is possible to secure a bypass communication path with a simple and inexpensive configuration.
[0027]
In each of the above-described embodiments, an example of an ADSL system or a VDSL system is described. The present invention can be applied to various data communication systems including xDSL systems such as systems. In this case, the ADSL router 2 and the VDSL router 22 which are data communication control devices are the ADSL modem 6 which is a modem capable of ADSL communication and the VDSL modem 26 which is a modem capable of VDSL communication. An xDSL modem that is a modem capable of xDSL communication is used.
[0028]
【The invention's effect】
According to the data communication system of the present invention, since it is not necessary to prepare a plurality of physical lines, it is possible to secure a bypass communication path with a simple and inexpensive configuration.
Further, according to the data communication control device of the present invention, it is not necessary to prepare a plurality of physical lines, and it is possible to construct a data communication system that can secure a detour communication path with a simple and inexpensive configuration.
[Brief description of the drawings]
FIG. 1 is a block diagram of a data communication system and a data communication control apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram of a data communication system and a data communication control device according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 13 ... Terminal 2 as communication device, 12 ... ADSL router 3 as data communication control device ... LAN interface unit 4 as interface means ... IP routing unit 5 as routing means ... Line control unit 6 as communication control means ADSL modem 7 as first communication means Analog modem 8 as second communication means DSL splitter 9 as splitter means Physical Subscriber line 10 as a typical communication path ... Analog telephone network 11 ... Internet 22, 212 ... VDSL router 26 as data communication control device ... VDSL modem 27 as first communication means ..Terminal adapter 210 as second communication means ISDN network

Claims (4)

In a data communication system that performs data communication between a plurality of communication devices using a physical communication path,
ADSL modem that performs communication of the first form among a plurality of communication devices via a physical communication path, and communication of the second form between the plurality of communication apparatuses via the physical communication path When a failure occurs in data communication between the analog modem and the plurality of communication devices performed by the ADSL modem via the physical communication path, the communication from the ADSL modem is switched to the communication by the analog modem. By performing the data communication between the plurality of communication devices via the same physical communication path in different communication forms, and determining that the communication path via the ADSL modem has been restored, the analog with instructs the line disconnection to the modem, and a communication control means for switching the communication by the ADSL modem, the ADSL modem and a Log modem is made using band is different from one another,
The communication control means monitors the line connection state of the ADSL modem while receiving an IP packet via the analog modem, and when the line is connected, the communication device is addressed to the ADSL router connected to the LAN. A data communication system, wherein an echo request message is transmitted and an echo response message from the ADSL router for the echo request message is confirmed, and it is determined that the communication path via the ADSL modem has been restored . The communication control means always monitors the line connection state of the ADSL modem and the arrival confirmation of the IP packet by the Internet protocol, and the line connection of the ADSL modem cannot be performed due to a path failure, or the arrival confirmation of the IP packet is continuously performed. 2. The data communication system according to claim 1 , wherein if the communication fails, it is determined that a failure has occurred and the communication is switched from communication by the ADSL modem to communication by the analog modem. In a data communication control device that controls data communication performed between a plurality of communication devices using a physical communication path,
ADSL modem that performs communication of the first form among a plurality of communication devices via a physical communication path, and communication of the second form between the plurality of communication apparatuses via the physical communication path When a failure occurs in data communication between the analog modem and the plurality of communication devices performed by the ADSL modem via the physical communication path, the communication from the ADSL modem is switched to the communication by the analog modem. By performing the data communication between the plurality of communication devices via the same physical communication path in different communication forms, and determining that the communication path via the ADSL modem has been restored, the analog with instructs the line disconnection to the modem, and a communication control means for switching the communication by the ADSL modem, the ADSL modem and a Log modem is made using band is different from one another,
The communication control means monitors the line connection state of the ADSL modem while receiving an IP packet via the analog modem, and when the line is connected, the communication device is addressed to the ADSL router connected to the LAN. A data communication control device characterized in that when an echo request message is transmitted and an echo response message from the ADSL router for the echo request message is confirmed, it is determined that the communication path via the ADSL modem has been restored. . The communication control means always monitors the line connection state of the ADSL modem and the arrival confirmation of the IP packet by the Internet protocol, and the line connection of the ADSL modem cannot be performed due to a path failure, or the arrival confirmation of the IP packet is continuously performed. 4. The data communication control device according to claim 3 , wherein if the operation fails, it is determined that a failure has occurred, and the communication is switched from communication by the ADSL modem to communication by the analog modem.

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