Abstract:
When a communications carrier uses another company&#39;s network as a relay network, it is necessary to monitor the health of and to perform maintenance for the lines from end to end in the other company&#39;s network as well as the network managed by this carrier. Terminal devices capable of terminating a CCM frame or other OAM signal are installed in users bases, and the health is monitored from end to end between the bases. Furthermore, a control device that controls the terminal devices is installed in the VLAN network used by the user, and remote control of the terminal devices is implemented from the controller. Table information held by the controller is managed collectively under the leadership of an operator, and information about the subordinate terminal devices connected to the controller is reported to the operator on the basis of results of the MAC learning by the controller. IDs managed by the carrier are specified in the connectivity monitoring segments by the operator, and connectivity can be monitored segment by segment.

Description:
INCORPORATION BY REFERENCE 
       [0001]    The present application claims priority from Japanese application JP 2011-083246 filed on Apr. 5, 2011, the content of which is hereby incorporated by reference into this application. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a network configuration for monitoring connectivity of a communication line that strides over a packet communication network in different manager and a method for controlling the network configuration. 
       BACKGROUND ART 
       [0003]    Recently, Ethernet (trademark) rapidly becomes widespread not only in a LAN (Local Area Network) area but also in a carrier network such as a wide-area Ethernet service. However, as compared to other protocols used in conventional transmission networks such as an ATM (Asynchronous Transfer Mode), an OAM (Operation Administration and Maintenance) function is not defined with respect to a packet communication protocol starting with Ethernet. Therefore, maintenance and management functions thereof have been addressed. 
         [0004]    Recently, in ITU-T (International Telecommunication Union Telecommunication Standardization) and IEEE (Institute of Electrical and Electronics Engineers, Inc.) as a standard-setting organization, discussions about the maintenance and management functions are performed. At this time, ITU-T recommendation Y.1731 (Non Patent Literature 1) and IEEE 802. lag (Non Patent Literature 2) are specified and an OAM function for Ethernet is introduced. In addition, specifications of a path switching (protection) system G 8031 (Non Patent Literature 3) using an OAM function are also completed. 
         [0005]    Through the process, since maintenance and management are enabled with regard to communication service in an Ethernet network, practical application of the OAM function starts in a packet communication network including Ethernet. Ethernet is usually applied to a LAN owned by an individual user or a corporate user in many cases. Since Ethernet has the maintenance and management functions, an operation thereof is taken notice of also in infrastructure services presented by a carrier. Also about a customer station equipment installed in a user&#39;s home, introduction of Ethernet OAM (hereinafter, referred to as Ethernet OAM) is studied. 
         [0006]    Conventionally, a carrier has presented services for establishing a relay network between user&#39;s sites through a common carrier leased line or L2-VPN (Layer 2 Virtual Private Network) service. The user of this case may be mainly a corporate user such as a corporate, in many cases. A corporate user has a plurality of sites according to a size of a business such as a headquarters office and a branch office in many cases and mutually performs communication between sites by using a common carrier leased line or L2-VPN service presented by a carrier. When using the services, a corporate user easily shares servers and files as a merit between a plurality of sites. In addition, a network can be established dispersedly into a headquarters office and a data center in consideration of diversification of risk at the time of disaster. 
         [0007]    In services for establishing a relay network for connecting both sites of users at these places separated geographically, a band guarantee is performed in accordance with a contract with a user in the relay network presented by a carrier. An access network provider that presents an infrastructure near a user for communication between sites mutually separated, or a carrier that presents a core network for connecting both of access networks strides over a plurality of networks in different managers. Therefore, it is difficult to perform monitoring from end to end between devices used by users. 
         [0008]    Along with standardization of the above-described Ethernet OAM, maintenance and management can be performed in a protocol of a Layer 2 (hereinafter, referred to as an L2). Further, an access network provider moves from a common carrier leased line device with high cost to a packet communication device. As described above, when both of an access network and a core network are connected through a packet communication device, connection for consistently managing them is conventionally difficult; however, can be easily established. Concretely, a carrier that presents a core network installs a remote device in a user site. Further, a method for managing the entire communication between user sites over an access network provider is being introduced. 
       CITATION LIST 
     Non Patent Literature 
       [0000]    
       
         Non Patent Literature 1: ITU-T Recommendation Y. 1731 
         Non Patent Literature 2: IEEE 802. lag 
         Non Patent Literature 3: ITU-T Recommendation G 8031/Y. 1342 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0012]    When a large-scale network between users is presented up to now, a communications carrier such as a carrier pays reasonable cost according to a scale of the network to establish it. Recently, a case of using an access network presented by other companies increases to enlarge an area of the L2-VPN service. The above-described cost reduction is achieved by using an area network established by a regional agent being an access network provider. When a communications carrier uses another company&#39;s network as a relay network, it is necessary to monitor the normality of and to perform maintenance for the lines from end to end in the other company&#39;s network as well as the network managed by this carrier. To monitor the lines from end to end, it is necessary to install a terminal device that has been prepared by the communications carrier in a user&#39;s home that uses an L2-VPN service. The terminal device is installed in a user&#39;s home, so it must perform remote control via the other company&#39;s network, and the method of that remote control must be addressed. Further, in case of trouble due to a terminal failure or a communication path error, there is the possibility that a trouble is detected not only from a device of a communications carrier such as a carrier but also from devices of other companies and unnecessary malfunction reports are congested. To solve the problems, a burden onto user traffic is relieved by identifying a failure segment effectively and reducing unnecessary malfunction reports. 
       Solution to Problem 
       [0013]    Terminal devices capable of terminating a CCM frame or other OAM signal are installed in user&#39;s bases, and the normality is monitored from end to end between bases. Further, a control device that controls the terminal devices is installed in the VLAN network used by the user, and remote control of the terminal devices is achieved by the controller. Table information held by the controller is managed collectively under the leadership of an operator, and information on the subordinate terminal devices connected to the controller is reported to the operator based on results of MAC learning by the controller. IDs managed by the carrier are specified in connectivity monitoring segments by the operator, and connectivity can be monitored in units of segments. 
       Advantageous Effects of Invention 
       [0014]    According to the present invention, remote control of each terminal device can be achieved via the controller from a MAC address learnt by the controller under the leadership of the operator. The operator can set a subordinate relationship of the terminal device via the controller. Further, the operator can set IDs of the connectivity monitoring segments of connecting a master terminal device and a slave terminal device, and those of connecting the controller and each terminal device. The operator can manage and prepare collectively a table indicating connection information between respective terminal devices that make a connection between bases in the L2-VPN service area and that indicating connection information between the controller and respective terminal devices. Based on the above, the operator can confirm the normality of not only a main signal route through which a user frame flows, but also a control route. Through the apparent connectivity monitoring segments, when a terminal failure in case of trouble or a failure portion at the time of a communication path error is easily identified and unnecessary malfunction reports are reduced, the operator can relieve a burden onto user traffic. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  illustrates one example of a network construction of an L2-VPN network according to an embodiment of the present invention; 
           [0016]      FIG. 2  illustrates one example of a network construction example according to the embodiment of the present invention; 
           [0017]      FIG. 3  illustrates one example of a process flow of a control method performed by an operator at the time of constructing a network according to the embodiment; 
           [0018]      FIG. 4A  illustrates one example of a table into which an operator needs to input at the time of constructing the embodiment of the present invention; 
           [0019]      FIG. 4B  illustrates one example of a table into which the operator needs to input at the time of constructing the embodiment of the present invention; 
           [0020]      FIG. 4C  illustrates one example of a table into which the operator needs to input at the time of constructing the embodiment of the present invention; 
           [0021]      FIG. 4D  illustrates one example of a table into which the operator needs to input at the time of constructing the embodiment of the present invention; 
           [0022]      FIG. 4E  illustrates one example of a table into which the operator needs to input at the time of constructing the embodiment of the present invention; 
           [0023]      FIG. 4F  illustrates one example of a table into which the operator needs to input at the time of constructing the embodiment of the present invention; 
           [0024]      FIG. 5  illustrates one example of a connectivity monitoring range capable of being monitored by an operator according to the embodiment of the present invention; 
           [0025]      FIG. 6  is the entire operation sequence diagram in which a control device (controller) is registered by an operator; 
           [0026]      FIG. 7  is the entire operation sequence diagram in which a terminal device (Box-M/S) is registered by the operator; 
           [0027]      FIG. 8  illustrates one example of a process flow of the control device (controller); 
           [0028]      FIG. 9A  illustrates one example of an internal table about connection information to be managed by the control device (controller); 
           [0029]      FIG. 9B  illustrates one example of an internal table about connection information to be managed by the control device (controller); 
           [0030]      FIG. 9C  illustrates one example of an internal table about connection information to be managed by the control device (controller); 
           [0031]      FIG. 9D  illustrates one example of an internal table about connection information to be managed by the control device (controller); 
           [0032]      FIG. 9E  illustrates one example of an internal table about connection information to be managed by the control device (controller); 
           [0033]      FIG. 9F  illustrates one example of an internal table about connection information to be managed by the control device (controller); 
           [0034]      FIG. 9G  illustrates one example of a configuration of the control device (controller); 
           [0035]      FIG. 10  illustrates one example of a process flow of a center side terminal device (Box-M); 
           [0036]      FIG. 11A  illustrates one example of a table about connection information to be managed by the center side terminal device (Box-M); 
           [0037]      FIG. 11B  illustrates one example of a table about connection information to be managed by the center side terminal device (Box-M); 
           [0038]      FIG. 11C  illustrates one example of a table about connection information to be managed by the center side terminal device (Box-M); 
           [0039]      FIG. 11D  illustrates one example of a table about connection information to be managed by the center side terminal device (Box-M); 
           [0040]      FIG. 11E  illustrates one example of a configuration of the center side terminal device (Box-M); 
           [0041]      FIG. 12  illustrates one example of a process flow of a base side terminal device (Box-S); 
           [0042]      FIG. 13A  illustrates one example of a table about connection information to be managed by the base side terminal device (Box-S); 
           [0043]      FIG. 13B  illustrates one example of a table about connection information to be managed by the base side terminal device (Box-S); 
           [0044]      FIG. 13C  illustrates one example of a table about connection information to be managed by the base side terminal device (Box-S); 
           [0045]      FIG. 13D  illustrates one example of a table about connection information to be managed by the base side terminal device (Box-S); and 
           [0046]      FIG. 13E  illustrates one example of a configuration of the base side terminal device (Box-S). 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0047]    Hereinafter, with reference to drawings, configurations and operations of a network according to the present invention will be described by using as an example an Ethernet OAM configuration specified by ITU recommendation Y. 1731 (Non Patent Literature 1) and operations thereof. 
         [0048]      FIG. 1  illustrates one example of a network configuration of an L2-VPN network  10  according to an embodiment of the present invention. In a network  1 , a terminal (hereinafter, referred to as a user device) of a user (subscriber) subscribing to a service for making a connection between bases is arranged at each site, and conditions that a Box-S 31  and a Box-M 40  being a terminal device similarly arranged at each site connect the user devices to the L2-VPN network  10  are illustrated. Here, the Box-M 40  is a terminal device that is, for example, arranged at a center side of a large city in which a user summarizes each base. Further, the Box-S 31  is a terminal device that is, for example, arranged by a user at a base side of a local region. This terminal device may be a single device, or incorporated into a device of a home gateway for Edge installed at a user&#39;s home and a station of a subscriber, or incorporated into a relay device such as a router or a switch. 
         [0049]    The terminal device is, for example, a device that terminates an OAM signal of a CCM (Continuity Check Message) frame to be used inside a base of the user or outside a base of the user. In the present embodiment, the terminal device is arranged inside the base of the user and further may be arranged outside a base near to the base of the user. 
         [0050]    A terminal device installed at each site is connected to an edge device  20  such as an L2 switch arranged at an edge of the relaying L2-VPN network  10 , and performs communication in a network under setting of ULAN, if needed. 
         [0051]    Here, the edge device  20 , the Box-M 40 , and the Box-S 31  are, for example, devices owned by a carrier being a communications carrier. A usage pattern that the Box-M 40  and the Box-S 31  are lent to the user by the carrier and installed in a user&#39;s home or station is supposed. Further, a network between the edge device  20  and a terminal device such as the Box-M 40  or the Box-S 31  may be configured by a network managed by a regional agent other than a carrier such as an access network provider. Further, a network interposed by the edge device may be considered as a network managed by a carrier. About the fact that who manages which part of the network of  FIG. 1 , various variations are considered also in other than the above-described examples. The present embodiment can be performed even if how the network  1  is partitioned and managed. 
         [0052]    In  FIG. 1 , five Boxes-S 31  of a Box-S 1  ( 31 A), a Box-S 2  ( 31 B), a Box-S 3  ( 31 C), a Box-S 4  ( 31 D), and a Box-S 5  ( 31 E) are arranged as terminal devices at the base side of the user in a local region. Further, one Box-M 40  is arranged as a terminal device at the center side. In addition, a controller  50  that remotely controls each terminal device is also connected via the edge device  20 F such as the L2-VPN network  10  and the L2 switch. The controller  50  is connected to a monitoring control system  190  and a communication path (control plane) constructed for transmitting and receiving Ethernet OAM signals apart from a communication path (data plane) through which a user frame flows. The monitoring control system  190  is composed of a server group as hardware and an application software group. A device management of the controller  50 , the Box-M 40 , and the Box-S 31  is performed via the control plane and further constructions and monitoring of the network are also performed at the same time. 
         [0053]      FIG. 2  illustrates one example of a network construction example according to the embodiment of the present invention. The controller  50 , the Box-M 40 , the Box-S 1  ( 31 A), the Box-S 2  ( 31 B), and the Box-S 3  ( 31 C) construct via the L2-VPN network  10  a network set in a VLAN A (for users)  140 . Similarly, the controller  50 , the Box-M 40 , the Box-S 4  ( 31 D), and the Box-S 5  ( 31 E) construct via the L2-VPN network  10  a network set in a VLAN B (for users)  141 . Between respective terminal devices, the VLAN A (for users)  140  and the VLAN B (for users)  141  are communication paths (data plane) through which a user frame used in communication between the base and the center by the user flows, and also a communication path (control plane) for transferring Ethernet OAM signals that perform connectivity monitoring between terminal devices. Further, a pattern that a plurality of base side Boxes-S 31  are subject under one center side Box-M 40  is taken between respective terminal devices. With reference to one example, in some corporate network, a terminal device installed in a branch office is arranged in a user device connected ahead of the base side Box-S 31 . Further, a data center that controls each branch office is installed in a user device connected ahead of the center side Box-M 40 . They construct networks that mutually transmit and receive signals. The above-described example is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0054]      FIG. 3  illustrates one example of a process flow about a control method performed by the operator at the time of constructing the network according to the embodiment. The controller  50  and a Box  30  are supposed to be preliminarily installed and connected to the edge SW  20  in an initial state. A user terminal connected to the controller  50  is referred to as a Box. 
         [0055]    At the beginning, the operator registers devices and performs a controller registration work  3100 . The operator registers the controller and a user VLAN ID in a table  4010  illustrated in  FIG. 4A . The user VLAN ID is a VLAN ID for a communication path through which a user frame used in communication between the base and the center by the user flows. The operator preliminarily constructs a network through which a user frame flows, and therefore previously grasps the user VLAN ID. Here, since the above-described network  1  of  FIG. 2  is taken as an example, a VLAN ID A and a VLAN ID B are registered in the user VLAN ID in a table  4020  of  FIG. 4B . 
         [0056]    Next, a device registration and a Box-M/S registration work  3200  are performed. An M/S (Master/Slave) setting and registration of Box-M/Box-S devices illustrated in a table  4030  of  FIG. 4C  are input. In  FIG. 4C , the registration and the user VLAN ID of the controller registered in  FIG. 4B  are reflected, and SNs (Serial Number) and MAC addresses of the user terminal connected to the controller  50  corresponding to this VLAN ID are registered. The SN is information for uniquely discriminating user terminals and, for example, a serial number given by a manufacturer at the time of manufacturing a device and identification information newly given by a manager that manages a network of a communication carrier may be used. A method for obtaining an SN and a MAC address of each connected Box by inputting the user VLAN ID A will be described later. 
         [0057]    In a table  4040  of  FIG. 4D , a state where the setting is reflected is illustrated. Four Boxes belong to the user VLAN ID A, and the SNs are S 000 , S 001 , S 002 , and S 003 . Further, a Box with the SN of S 000  and the MAC address of MAC  100  is registered as the Box-M 40 , and a Box with the SN of S 001  and the MAC address of MAC  200  is registered as the Box-S 1  ( 31 A). Similarly, a Box with the SN of S 002  and the MAC address of MAC  300  is registered as the Box-S 2  ( 31 B), and a Box with the SN of S 003  and the MAC address of MAC  400  is registered as the Box-S 3  ( 31 C). 
         [0058]    Three Boxes belong to the user VLAN ID B, and the SNs are S 000 ,  5004 , and S 005 . Further, a Box with the SN of S 000  and the MAC address of MAC  100  is registered as the Box-M( 40 ), and a Box with the SN of S 004  and the MAC address of MAC  500  is registered as the Box-S 4  ( 31 D). Similarly, a Box with the SN of S 005  and the MAC address of MAC  600  is registered as the Box-S 5  ( 31 E) 
         [0059]    Next, setting of line parameters and setting of the connectivity monitoring  3300  are performed. A table  4050  of  FIG. 4E  differs from the table  4040  of  FIG. 4D  in an arrangement, and a table is rearranged and reflected by performing the device registration and the Box-M/S registration work  3200 . As a way to see a table, the Box-S 1  ( 31 A) (the SN is S 001  and the MAC address is MAC 200 ), the Box-S 2  ( 31 B) (the SN is S 002  and the MAC address is MAC 300 ), and the Box-S 3  ( 31 C) (the SN is S 003  and the MAC address is MAC 400 ) are connected under the Box-M 40  (the SN is S 000  and the MAC address is MAC 100 ) belonging to the user VLAN ID A. 
         [0060]    Similarly, the Box-S 4  ( 31 D) (the SN is S 004  and the MAC address is MAC 500 ) and the Box-S 5  ( 31 E) (the SN is S 005  and the MAC address is MAC 600 ) are connected under the Box-M 40  (the SN is S 000  and the MAC address is MAC 100 ) belonging to the user VLAN IDB. 
         [0061]    In setting of the line parameters and setting of the connectivity monitoring  3300 , a line ID, a terminal ID (Box-S side), a terminal ID (Box-M side), and valid/invalid setting of the connectivity monitoring are performed in a column of an ID in a table  4050  of  FIG. 4E . One example of setting of each line parameter is illustrated in  FIG. 5 . The line ID is an ID indicating a connectivity monitoring segment between the Box-M 40  and the Box-S 1  ( 31 A). In this example, an MS  1  ( 6100 ) is set as the line ID. The terminal ID (Box-S side) is an ID indicating the connectivity monitoring segment between the controller  50  and the Box-S 1  ( 31 A). In this example, a CS 1  ( 6200 ) is set as the terminal ID (Box-S side). Similarly, the terminal ID (Box-M side) is an ID indicating the connectivity monitoring segment between the controller  50  and the Box-M 40 . In this example, a CMA ( 6300 ) is set as the terminal ID (Box-M side). Subsequently, setting of the line parameter is similarly performed and a table  4060  of  FIG. 4F  is completed. 
         [0062]    About connectivity monitoring results in the case where  FIG. 5  is taken as an example, the controller  50  confirms the connectivity monitoring results of the terminal ID (Box-M side) between the controller  50  and the Box-M 40  as well as those of the terminal ID (Box-S side) between the controller  50  and the Box-S 1  ( 31 A). About the connectivity monitoring results of a line ID between the Box-M 50  and the Box-S 1  ( 31 A), two ways are used; that is, one is to report the results from the Box-M 40  and the other is to report the results from the Box-S 1 . Here, since the Box-M 40  acts as a master, the connectivity monitoring results of the line ID are supposed to be reported from the Box-M 40 . Note, however, that this is adamantly one example, and the present invention is not necessarily limited to the above-described example. 
         [0063]      FIG. 6  is the entire operation sequence diagram for registering the control device (controller  50 ) by the operator. When the device registration and the controller registration work  3100  of  FIG. 3  are performed, registration of the controller  50  and setting of the user VLAN ID are performed. The controller  50  is started from an initial state  7010  and operated  7100  through the controller registration and the setting of the VLAN ID by the operator. The controller  50  uses the user VLAN ID set by the operator and transmits a multicast CCM frame to the Box  30  ( 7200 ). The Box  30  connected by using the same user VLAN ID continuously receives the multicast CCM frame transmitted from the controller  50 . At this time, the Box  30  transmits to the controller  50  a unicast CCM frame signal to which the VLAN ID used by the received multicast CCM frame is attached ( 7300 ). When the unicast CCM frame is transmitted, a MAC address of the controller  50  is set to a destination address (Destination MAC Address) (hereinafter, referred to as a DA) to transmit the destination MAC address. 
         [0064]    In this case, the CCM (Continuity Check Message) frame used for connectivity monitoring in an Ethernet OAM may be applied. 
         [0065]    In the case where a multicast CCM frame is transmitted, for example, a multicast MAC address for the OAM frame specified by non patent literature 1 is used. When this multicast MAC address is used, the terminal device receiving an Eth-CC signal confirms that the multicast MAC address specified by standards is stored in the destination MAC address, for processing. 
         [0066]    The controller  50  learns a MAC address of the Box  30  from a source address (Source MAC Address) (hereinafter, referred to as an SA) being the MAC address of the unicast CCM frame transmitted by the Box  30 . Next, the controller  50  transmits a VSM frame to which the user VLAN ID is attached by using the learnt MAC address of the Box  30 . The VSM frame differs from the CCM frame in that an Opcode is equal to 0x33. The VSM frame is a frame independently settable by a vender, and here is a control frame for asking the Box  30  for information on the SN and the MAC address. A frame format has a static part of a vender itself and ways of various configurations, and therefore is omitted. 
         [0067]    The Box  30  that receives the VSM frame to itself transmits information on the SN and the MAC address of itself to the controller  50  through a VSR frame. The VSR frame differs from the CCM frame in that an Opcode is equal to 0x32. The VSR frame is a frame independently settable by the vender, and here is a control frame for reporting information on the SN and the MAC address of the Box  30  itself to the controller  50 . A frame format has a static part of the vender itself and therefore is omitted. The MAC address is previously learnt by the controller  50  by using a CCM. Here, the Box  30  transmits the MAC address of itself through the VSR frame again to confirm accord between the SN and the MAC. 
         [0068]    A reference numeral  7400  of  FIG. 6  denotes transmission of the VSM frame from the controller  50  to the Box  30  and reception of the VSR frame from the Box  30  to the controller  50 . The controller  50  updates an inner table of itself based on the information received from the Box  30  through the VSR frame, and reports the information to the operator side. The report information of this time includes information on the Box  30  connected in units of the user VLAN ID and information on the SN and the MAC address of the Box  30  itself. In the multicast CCM frame  7200 , the unicast CCM frame  7300 , and the collection of the VSM/VSR individual information  7400  of  FIG. 6 , the above-described operations may be always continued in a predetermined time interval at the time of the operation  7100  of the controller  50  or later. A reason of the continuation is a newly added information collection purpose of the Box  30 . A sequence of only the controller  50  will be described later with reference to  FIG. 8 . Further, the above-described flow is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0069]      FIG. 7  is the entire operation sequence diagram for registering the terminal device (Box-M/S) by the operator. When the device registration and the Box-M/S registration work  3200  of  FIG. 3  are performed, contents input by the operator are reflected on the inner table of the controller  50  for updating. Based on the updated contents of the inner table, the controller  50  transmits registration setting as a master (Box-M 40 ) to the Box  40  through a VSM frame. When the VSM frame is received, the Box  40  starts operations as the Box-M 40  based on the setting contents and, through the VSR frame, reports to the controller  50  that it operates as the Box-M 40 . The controller  50  reports to the operator that setting of the Box-M 40  is completed. 
         [0070]    Based on the updated contents of the inner table, the controller  50  similarly transmits the registration setting as a slave (Box-S 31 ) to the Box  31  through the VSM frame. When the VSM frame is received, the Box  31  starts operations as a Box-S 31 A based on the setting contents and, through the VSR frame, reports to the controller  50  that it operates as the Box-S 31 A. The controller  50  reports to the operator that setting of the Box-S 31 A is completed. The operations are denoted by a reference numeral  8000 . 
         [0071]    When the setting of the line parameter and the setting of the connectivity monitoring  3300  of  FIG. 3  are performed, contents input by the operator are reflected on the inner table of the controller  50  for updating. Based on the updated contents of the inner table, the controller  50  transmits information on the setting of the line parameter and the valid setting of the connectivity monitoring to the Box-M 40  through the VSM frame. When the VSM frame is received, the Box-M 40  reflects the setting contents on the table of itself and is in an operating state. Through the VSR frame, the Box-M 40  reports to the controller  50  that it is in an operating state. The controller  50  reports to the operator that the setting of the Box-M 40  is completed. 
         [0072]    Based on the updated contents of the inner table, the controller  50  similarly transmits to the Box-S 31  the information on the setting of the line parameter and the valid setting of the connectivity monitoring through the VSM frame. When the VSM frame is received, the Box-S 31  reflects the setting contents on the table of itself and is in an operating state. The Box-S 31  reports to the controller  50  that it is in an operating state. The controller  50  reports to the operator that the setting of the Box-S 31  is completed. The operations are denoted by a reference numeral  8100 . 
         [0073]    Here, descriptions are made with a focus on the Box-M 40  and the Box-S 31 , and practically, a plurality of Boxes  31  can be registered as the Box-M 40  or the Box-S 31 . The above-described flow is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0074]    Separately, sequences of only the controller  50 , only the Box-M 40 , and only the Box-S 30  will be described later with reference to  FIGS. 8 ,  10 , and  12 , respectively. 
         [0075]      FIG. 8  illustrates one example of a process flow of the control device (controller  50 ). The controller  50  has an inner table  9000  ( FIG. 9G ). In an initial state  7010 , an inner table  10010  of  FIG. 9A  is blank. When the registration setting of the controller  50  and the user VLAN ID setting  3100  are performed by the operator, the controller  50  is in an operating state ( 7100 ). 
         [0076]    When being in an operating state, the controller  50  transmits a multicast CCM with the user VLAN to the Box  31  and the Box  40  by using the user VLAN ID set by the operator ( 9110 ). The controller  50  receives a unicast CCM with the user VLAN from the Box  31  and the Box  40  ( 9120 ). Further, when the unicast CCM with the user VLAN is received, the controller  50  learns the MAC addresses of the Box  31  and the Box  40 , and prepares an inner table ( 9130 ). 
         [0077]    An inner table  10020  of  FIG. 9B  results from reflecting the MAC learning result of the Box  31  and the Box  40  on the inner table  10010  of  FIG. 9A . Here, since the above-described network  1  of  FIG. 2  is taken as an example, a destination MAC corresponds to MAC  100 , MAC  200 , MAC  300 , and MAC  400  in the user VLAN-ID A in the inner table  10020  of  FIG. 9B . Similarly, a destination MAC corresponds to MAC  100 , MAC  500 , and MAC  600  in the user VLAN-ID B. 
         [0078]    Next, the controller  50  makes inquiries about detailed information of the individual Box  31  and Box  40  based on the learnt MAC address of the Box  31  and the Box  40 . Concretely, the controller  50  makes inquiries about the SN information of the Box  31  and the Box  40 , and reconfirms the MAC address of the Box  30 . The controller  50  transmits the unicast VSM frame with the user VLAN to the Box  31  and the Box  40  ( 9140 ). 
         [0079]    The controller  50  receives the unicast VSR frame with the user VLAN from the Box  31  and the Box  40 , and updates information of the previously prepared inner table based on the received contents of the unicast VSR frame ( 9160 ). 
         [0080]    An inner table  10030  of  FIG. 9C  results from reflecting the received contents of the unicast VSR frame from the Box  30  on the inner table  10020 . Here, since the above-described network  1  of  FIG. 2  is taken as an example, in the inner table  10030  of  FIG. 9C , the destination MACs of MAC  100 , MAC  200 , MAC  300 , and MAC  400  correspond to the destination SNs of S 000 , S 001 , S 002 , and S 003 , respectively, in the user VLAN-ID A. Similarly, the destination MACs of MAC  100 , MAC  500 , and MAC  500  correspond to the destination SNs of S 000 , S 004 , and S 004 , respectively, in the user VLAN-ID B. When the inner table information  10030  of  FIG. 9C  is completed, the controller  50  reports the table contents to the operator side. 
         [0081]    When the device registration and the Box-M/S registration work  3200  are performed by the operator, the controller  50  updates an inner table ( 9210 ). An inner table  10040  of  FIG. 9B  results from reflecting contents of the Box-M/S registration work  3200  from the operator on the inner table  10030 . Here, since the above-described network  1  of  FIG. 2  is taken as an example, in the inner table  10040  of  FIG. 9D , the destination SNs of S 000 , S 001 , S 002 , and S 003  correspond to the Box-M 40 , the Box-S 1  ( 31 A), the Box-S 2  ( 31 B), and the Box-S 1  ( 31  C), respectively, in the user VLAN-ID A. 
         [0082]    Similarly, the destination SNs of S 000 , S 004 , and S 005  correspond to the Box-M 40 , the Box-S 1  ( 31 D), and the Box-S 1  ( 31 E), respectively, in the user VLAN-ID B. 
         [0083]    Based on the table information of the inner table  10040 , the controller  50  transmits the unicast VSM frame to the Box  31  and the Box  40  ( 9220 ). The controller  50  receives a Box M/S setting response from the Box through the unicast VSR frame ( 9230 ). 
         [0084]    An inner table  10050  of  FIG. 9E  is prepared based on the information collected up to now. The inner table  10050  is prepared in combination with information on the inner table  10040  of  FIG. 9D  and that on the tables  4020  and  4040  of  FIGS. 4B and 4D . The SN and the MAC address being information on the control device (controller  50 ) itself, the SN and the MAC address being information on the center side terminal device (Box-M 40 ) accommodated in the controller  50 , and the SN and the MAC address being information on the base side terminal device (Box-S 31 ) accommodated in the Box-M 40  are indicated in units of the user VLAN-ID. The above-described accommodation relationship is completed when the controller registration work  3100  and the Box-M/S registration work contents c 3200  by the operator are performed. 
         [0085]    Next, when the setting of the line parameter and the setting of the connectivity monitoring  3300  are performed by the operator, the controller  50  updates the inner table ( 9240 ). An inner table  10060  of  FIG. 9F  results from reflecting the setting of the line parameter and the setting contents of the connectivity monitoring by the operator on the inner table  10050 . 
         [0086]    Based on the table information of the inner table  10050 , the controller  50  transmits the unicast VSM frame to the Box M/S ( 9250 ). The transmission contents of the VSM frame include the setting of the line parameter and the setting of the connectivity monitoring. The controller  50  receives a setting response from the Box-M/S through the unicast VSR frame ( 9260 ). The above indicates operation setting of the Box-M 40  and the Box-S 31  from the controller  50 . 
         [0087]    A dotted line portion of  FIG. 8  indicates a sequence of the connectivity monitoring after operations of the Box-M 40  and the Box-S 31 . The controller  50  starts the connectivity monitoring between itself and any of the Box-M 40  and the Box-S 31  ( 9339 ). 
         [0088]    Concretely, based on the inner table  10060  of  FIG. 9F , the controller  50  transmits the unicast CCM frame in units of the line parameter, that is, to the terminal ID (Box-S side) and the terminal ID (Box-M side). In the above-described example, since the MAC addresses of the Box-M 40  and the Box-S 31  accommodated in the controller  50  are grasped, the unicast CCM frame is used; further, the multicast CCM frame may be used. In this example, the unicast CCM frame is used in order to reduce a burden onto user traffic. 
         [0089]    The controller  50  receives a response of the unicast CCM frame from the Box-M 40  and the Box-S 31  and finishes the connectivity monitoring between itself and any of the Box-M 40  and the Box-S 31  ( 9320 ). Further, the controller  50  summarizes results of the connectivity monitoring and updates the inner table ( 9330 ). 
         [0090]    A sequence of the dotted line portion  9300  is repeatedly performed on a steady basis. When a CCM frame is not received for a given length of time, or an abnormality occurs in connectivity between the controller  50  and a relevant device, a report to the operator is promptly performed. Other than the above, a regular report to the operator is set to about five minutes. The above-described example is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0091]      FIG. 10  illustrates one example of a process flow of the center side terminal device (Box-M 40 ). The Box-M 40  has an inner table  12000  ( FIG. 11E ). In the initial state  7020 , an inner table  13010  of  FIG. 11A  is blank. When the multicast CCM frame with the user VLAN is continuously received from the controller  50  five times ( 12010 ), the Box-M 40  releases an LOC (Loss Of Continuity). In the present embodiment, in order that the multicast CCM frame from other devices should not be erroneously learnt, the LOC is supposed to be not released until the multicast CCM frame is continuously received five times. Five-time continuous reception of the above-described example is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0092]    Next, the Box-M 40  learns the MAC address of the controller  50  being a transmission source MAC address of the multicast CCM frame received from the controller  50 , and reflects the learnt MAC address on the inner table for updating ( 12020 ). 
         [0093]    An inner table  13020  of  FIG. 11B  results from reflecting MAC learning results of the controller  50 . Here, since the above-described network  1  of  FIG. 2  is taken as an example, the MAC learning results include a MAC  1  of the user VLAN ID A and a MAC  1  of the user VLAN ID B from the controller  50 . 
         [0094]    The Box-M 40  sets the learnt MAC address as a DA (destination address) and transmits the unicast CCM frame with the user VLAN to the controller  50  ( 12030 ). Further, the Box-M 40  receives from the controller  50  the unicast VSM frame with the user VLAN for inquiring about detailed information ( 12040 ). With respect to the inquiry about the detailed information, the Box-M 40  reports information on the SN and the MAC address of itself to the controller  50  through the unicast VSR frame with the user VLAN ( 12050 ). 
         [0095]    Next, the Box-M 40  receives from the controller  50  information for setting itself, namely, information for setting itself as a master Box through the unicast VSM frame with the user VLAN ( 12060 ). The Box-M 40  receiving the information updates the inner table of itself ( 12070 ). 
         [0096]    An inner table  13030  of  FIG. 11C  results from reflecting contents on the setting of the Box-M 40  (setting as a master) by the controller  50 . Since the controller  50  reports that the Box-M 40  should start up as a master, the Box-M 40  rewrites a portion to be described as the “Box” in the table  13020  into the “Box-S” in the table  13030 . The reason is that the Box-M 40  inside has information on the Box-M 40  itself, namely, the SN and the MAC address, and that the Box-M 40  needs to manage the information, namely, the SNs, and the MAC addresses of a plurality of Boxes-S 31  in the case of operating as the Box-M 40 . The method is taken in order to delete the number of tables to be managed by the Box, namely, delete a memory amount. 
         [0097]    Further, the Box-M 40  transmits to the controller  50  the VSR frame for reporting that the setting is completed ( 12080 ). 
         [0098]    The Box-M 40  receives from the controller  50  information on the setting of the line parameter and the setting of the connectivity monitoring through the unicast VSM frame with the user VLAN ( 12090 ). When the unicast VSM frame with the user VLAN is received from the controller  50 , the Box-M 40  updates the inner table ( 12100 ). 
         [0099]    An inner table  13040  of  FIG. 11D  results from reflecting setting of the SN information, setting of the line parameter, and setting of the connectivity monitoring valid information of the controller set by the controller  50  on the inner table  13030 . Here, since the above-described network  1  of  FIG. 2  is taken as an example, the SN information C 001  of the controller  50  and information on the Box-S connected under the Box-M, namely, the SN and the MAC address (S 001 , S 002 , and S 003  correspond to MAC 200 , MAC 300 , and MAC 400 , respectively), information on the line ID and the terminal ID (Box-M side) of the line parameter, and the valid setting information on the connectivity monitoring in the user VLAN ID A are updated. Here, “-” is written in fields of the terminal ID (Box-S side). The reason is that the Box-M does not manage the terminal ID (Box-S side) between the controller  50  and the Box-S. Similarly, the SN information C 001  of the controller  50  and information on the Box-S connected under the Box-M, namely, the SN and the MAC address (S 004  and S 005  correspond to MAC 500  and MAC 600 , respectively), information on the line ID and the terminal ID (Box-M side) of the line parameter, and the valid setting information on the connectivity monitoring in the user VLAN ID B are updated. 
         [0100]    When the setting is normally completed, the Box-M 40  transmits a setting response report to the controller  50  through the unicast VSR frame ( 12110 ). Further, the Box-M 40  is in an operating state ( 8110 ). 
         [0101]    Based on the information on the inner table  13040 , the Box-M 40  performs the connectivity monitoring between the Box-M 40  and the Box-S 31  ( 12200 ). In addition, the Box-M 40  performs the connectivity monitoring between the controller  50  and the Box-M 40  at the same time ( 12300 ). 
         [0102]    About the connectivity monitoring between the Box-M 40  and the Box-S 31 , the Box-M 40  transmits the multicast CCM to a plurality of Boxes-S 31  accommodated in units of the user VALN ID ( 12210 ). Further, the Box-M 40  receives the unicast CCM from the Box-S 31  ( 12220 ), updates the inner table based on the unicast CCM ( 12230 ), and reflects connectivity monitoring results on the inner table. 
         [0103]    About the connectivity monitoring between the Box-M 40  and the controller  50 , the Box-M 40  receives the unicast CCM from the controller  50  ( 12310 ). Further, the Box-M 40  transmits the unicast CCM to the controller  50  ( 12320 ). The Box-M 40  updates the inner table ( 12330 ), and reflects the connectivity monitoring results on the inner table. 
         [0104]    A sequence ( 12200 ) for performing the connectivity monitoring between the Box-M 40  and the Box-S 31  and a sequence ( 12300 ) for performing the connectivity monitoring between the Box-M 40  and the controller  50  are repeatedly performed on a steady basis. When a CCM frame is not received for a given length of time, or an abnormality occurs in connectivity between the controller  50  and a relevant device, a report to the operator is promptly performed. Other than the above, a regular report to the operator is set to about five minutes. The above-described example is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0105]      FIG. 12  illustrates one example of a process flow of the base side terminal device (Box-S). The Box-S 31  has an inner table  15000  ( FIG. 13E ). In the initial state  7030 , an inner table  16010  of  FIG. 13A  is blank. When the multicast CCM frame with the user VLAN is continuously received from the controller  50  five times ( 15010 ), the Box-S 31  releases a LOC (Loss Of Continuity). 
         [0106]    Next, the Box-S 31  learns the MAC address of the controller  50  being a transmission source MAC address of the multicast CCM frame received from the controller  50 , and reflects the learnt MAC address on the inner table for updating ( 15020 ). 
         [0107]    An inner table  16020  of  FIG. 13B  results from reflecting the MAC learning result of the controller  50  on the inner table. Here, since the above-described network  1  of  FIG. 2  is taken as an example, the MAC learning result includes a MAC  1  of the user VLAN ID A from the controller  50 . Since other Boxes-S belong to a network of the user VLAN ID B, only the Box-S 1  ( 31 A) belonging to a network of the user VLAN ID A is described. 
         [0108]    The Box-S 31  sets the learnt MAC address as a DA (destination address) and transmits the unicast CCM frame with the user VLAN to the controller  50  ( 15030 ). Next, the Box-S 31  receives from the controller  50  the unicast VSM frame with the user VLAN for inquiring about detailed information ( 15040 ). The Box-S 31  receiving the unicast VSM frame reports information on the SN and the MAC address of itself to the controller  50  through the unicast VSR frame with the user VLAN ( 15050 ). 
         [0109]    Next, the Box-S 31  receives from the controller  50  information for setting the Box-S 1  ( 31 A), namely, information for setting the Box-S 31  as a slave Box through the unicast VSM frame with the user VLAN ( 15060 ). The Box- 30  updates the inner table of itself ( 15070 ). 
         [0110]    An inner table  16030  of  FIG. 13C  results from reflecting contents on the setting of the Box-S 1  ( 31 A) by the controller  50 . Since the controller  50  reports that the Box- 30  should start up as the Box-S 1  ( 31 A), the Box- 30  rewrites a portion to be described as the “Box” in the table  16020  into the “Box-M” in the table  16030 . The reason is that the Box-S 1  ( 31 A) itself inside has information on the Box-S 1  ( 31 A) itself, namely, the SN and the MAC address, and that the Box-S 31  needs to manage the information on the Box-M 40  to be terminated, namely, the SN and the MAC address in the case of operating as the Box-S 1  ( 31 A). 
         [0111]    Further, the Box-S 31  transmits to the controller  50  the VSR frame for reporting that the setting is completed ( 15080 ). 
         [0112]    Next, the Box-S 31  receives from the controller  50  information on the setting of the line parameter and the setting of the connectivity monitoring through the unicast VSM frame with the user VLAN ( 15090 ). When the unicast VSM frame with the user VLAN is received from the controller  50 , the Box-S 31  updates the inner table ( 15100 ). 
         [0113]    An inner table  16040  of  FIG. 13D  results from reflecting the SN information of the controller set by the controller  50 , the setting of the line parameter, and the setting of the connectivity monitoring valid information on the inner table  16030 . Here, since the above-described network  1  of  FIG. 2  is taken as an example, the SN information C 001  on the controller  50  and information on the Box-M, namely, the SN and the MAC address (S 000  corresponds to MAC 100 ), information on the line ID and the terminal ID (Box-S side) in the line parameter, and the valid setting information on the connectivity monitoring in the user VLAN ID A are updated. Here, “-” is written in fields of the terminal ID (Box-M side). The reason is that the Box-M does not manage the terminal ID (Box-M side) between the controller  50  and the Box-M. 
         [0114]    When the setting is normally completed, the Box-S 1  ( 31 A) transmits a setting response report to the controller  50  through the unicast VSR frame ( 15110 ). Further, the Box-S 31  is in an operating state ( 8130 ). 
         [0115]    Based on the information on the inner table  16040 , the Box-S 31  performs the connectivity monitoring between the Box-M 40  and the Box-S 31  ( 15200 ). In addition, the Box-S 31  separately performs the connectivity monitoring between the controller  50  and the Box-S 31  ( 15300 ). 
         [0116]    About the connectivity monitoring between the Box-S 31  and the Box-M 40 , the Box-S 31  receives the unicast CCM from the Box-M 40  ( 15210 ). Further, the Box-S 31  transmits the unicast CCM to the Box-M 40  ( 15320 ). Further, the Box-S 31  updates the inner table in accordance with an exchange of the unicast CCM frame between the Box-S 31  and the Box-M 40  ( 15230 ), and reflects connectivity monitoring results on the inner table. 
         [0117]    About the connectivity monitoring between the Box-S 31  and the controller  50 , the Box-S 31  receives the unicast CCM from the controller  50  ( 15310 ). Further, the Box-S 31  transmits the unicast CCM to the controller  50  ( 15320 ). The Box-S 31  updates the inner table in accordance with an exchange of the unicast CCM frame between the Box-S 31  and the controller  50  ( 15340 ), and reflects connectivity monitoring results on the inner table. 
         [0118]    A sequence ( 15200 ) for performing the connectivity monitoring between the Box-M 40  and the Box-S 31  and a sequence ( 15300 ) for performing the connectivity monitoring between the Box-S 31  and the controller  50  are repeatedly performed on a steady basis. When a CCM frame is not received for a given length of time, or an abnormality occurs in connectivity between the Box-S 31  and a relevant device, a report to the operator side is promptly performed by the Box-S 31 . Other than the above, a regular report to the operator side is set to about five minutes. The above-described example is adamantly one example, and the present embodiment is not necessarily limited to the above-described example. 
         [0119]    As described above, in the present embodiment, a terminal device (hereinafter, referred to as a terminal device) that can terminate the Ethernet OAM frame specified by recommendation of IEEE 802. lag and ITU-T Y. 1731 is installed at a user&#39;s base. Further, normality monitoring between bases is achieved from end to end between terminal devices by using a CCM frame. Further, a control device (controller) that controls the terminal device is installed in a VLAN network used by a user. A method for establishing a control route of the terminal device from the controller is performed by MAC address learning and transmission and reception of a CCM frame between the controller and the terminal device. Concretely, a CCM frame with a multicast address is transmitted to each terminal device in a VLAN network used by the same user from the controller. When the CCM frame with the multicast address is received, each terminal device transmits a CCM frame with a unicast address to the controller. The controller learns a MAC address of an object terminal device based on the CCM frame with the unicast address from each terminal device. 
         [0120]    After the MAC address learning, an object device can be identified by a MAC address and a channel for control can be established. The terminal device is controlled by the controller through an independently-specified control frame. To a format of the control frame, in-channel communication of a layer 2 can be applied by using a VSM/VSR (Vender-Specific OAM Message/Vender-Specific OAM Reply) of an Ethernet OAM. The above-described format of the control frame is adamantly one example, and not limited to usage of the VSM/VSR. 
         [0121]    The controller that establishes a control route with the terminal device performs table management in units of a VLAN network in which the user uses information on the terminal device based on the MAC learning result and the report information on a control frame. Table information on the controller can be reported to an operator side and collectively managed. The operator sets a subordinate relationship to terminal devices and determines an upper-side (master) terminal device and a plurality of lower-side (slave) terminal devices. The controller reports the set contents to each terminal device through the control frame based on the set table information. Based on the set contents, each terminal device operates. About the connectivity monitoring, both of monitoring of a main signal route and that of a control route are performed. Concretely, the connectivity monitoring of the main signal route is performed through the CCM frame between the master terminal device and the slave terminal device. Further, the connectivity monitoring of the control route is performed through the CCM frame also between the controller and each terminal device. In a connectivity monitoring segment, an ID managed by the operator is specified, and monitored and managed in units of segments. 
         [0122]    As described above, each terminal device can be remotely controlled through the controller  50  under the leadership of an operator from a MAC address learnt by the controller  50 . The operator can manage and prepare collectively tables indicating connection information between respective terminal devices that make a connection between bases in an L2-VPN service area and connection information between a controller and each terminal device. Based on the above, the operator can confirm normality of not only a main signal route through which a user frame flows but also a control route. When a connectivity monitoring segment becomes apparent, a terminal failure in case of trouble or a failure portion at the time of a communication path error is easily identified. Further, when an unnecessary failure report is reduced, a burden onto user traffic can be relieved. 
         [0123]    It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modification may be made without departing from the spirit of the invention and the scope of the appended claims. 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               1  Network 
               10  L2 VPN network 
               31  Box-S 
               40  Box-M 
               50  Controller 
               6100  Line ID 
               6200  Terminal ID (Box-M side) 
               6300  Terminal ID (Box-S side)