JP2005006292A5 - - Google Patents

Description

Network system

  The present invention relates to a network system composed of a plurality of sub-networks connecting devices including a router device, and more particularly to a technique for automatically constructing a consistent network configuration when a router device connected to a sub-network is activated. About.

  With the expansion of communication networks, various transmission media exist. Various router devices (hereinafter also simply referred to as “routers”) that connect sub-networks (hereinafter also simply referred to as “subnets”) configured using the same or different types of transmission media have been developed. . All the same transmission media are used in the same subnet. In order to connect a plurality of subnets by introducing a router, identifiers (hereinafter referred to as “net IDs”) that uniquely identify the plurality of subnets are consistent (that is, have different values). Needed. Note that a sub-network is a smaller unit network that constitutes one network system.

  For this reason, conventionally, a technique has been proposed for confirming that there is no contradiction in the network configuration of a network system (hereinafter simply referred to as “system”) composed of a plurality of connected subnets when the router is started. (For example, refer to Patent Document 1).

In the above prior art, the router transmits a message data requesting a net ID to all connected subnets by broadcast in the subnet, and the network configuration is incomplete due to the number of responses received. Make sure there is no.
Japanese Patent No. 3373808

  However, in this prior art, when the network configuration in the system does not change as in the case of replacing a router, the router can be started without any problem. However, in order to integrate different systems with a new router, When starting up, network inconsistencies cannot be resolved automatically within the system.

  Therefore, the present invention solves such problems, and a convenient network system in which a consistent network configuration is automatically constructed only by starting up a router without special awareness of the user. The purpose is to provide.

In order to achieve the above object, a network system according to the present invention is a network system composed of a plurality of sub-networks connecting devices including a router device, and the plurality of sub-networks are identified by a net ID. In addition, the router device is connected in a tree shape via the router device, and the router device includes router information including communication means for connecting a plurality of sub-networks and net IDs of the plurality of sub-networks to which the communication means are connected. Router information storage means for storing, and cold start means for performing a cold start that is a startup process involving updating of router information stored in the router information storage means, the cold start means, In the execution of the cold start, the downstream sub-network Characterized in that to perform a cold start on all of the connected equipment. As a result, even when a plurality of different networks are integrated with a new router device, a device that is located downstream can also be cold-started in a chain by simply performing a cold start after connecting the router device to the multiple networks. Therefore, the network ID of the downstream subnetwork in the system is initialized, and a new network system having a consistent network configuration is automatically constructed.

  Here, the network system further includes a net ID server for assigning a net ID to the sub-network, and the cold start means stores the net ID given from the net ID server in the router information storage means. By doing so, the cold start may be performed. The cold start means is a network request for updating the net ID of the subnetwork to a net ID given from the net ID server to all devices connected to the downstream subnetwork. The device may be caused to perform a cold start by transmitting an ID write request. As a result, a cold start of the automatic setting router device in which the net ID is determined by the net ID server uniquely assigns a net ID to the downstream subnetwork, and automates the construction of the network system.

  Further, the cold start means may perform the cold start by storing a preset net ID in the router information storage means. Then, the cold start means sends a net ID write request which is a request to update the net ID of the subnetwork to a preset net ID for all devices connected to the downstream subnetwork. By transmitting, the device may execute a cold start. As a result, the network ID is uniquely assigned to the downstream subnetwork by the cold start of the manually set router device in which the net ID is determined by the manually set net ID server, and the construction of the network system is automated.

  The router device further acquires all router information obtained by collecting router information of all router devices connected to the network system, and stores the acquired all router information and the router information storage means. All router information distribution means for updating all the router information from the information and distributing the updated all router information to all the router devices connected to the network system may be provided. As a result, even when a plurality of systems are integrated with a new router device, new router information to which information accompanying the introduction of the router device is added is distributed to all router devices in the system. All router information updates associated with system integration are automated.

  The router device may further include a warm start unit that performs a warm start that is a startup process that does not involve updating the router information stored in the router information storage unit. The router information storage means stores, in addition to the router information, all router information obtained by collecting router information of all router devices connected to the network system. The warm start means, for example, The information related to the subnetwork to which the communication means is connected matches the router information stored in the router information storage means, and all the router information acquired through the subnetwork to which the communication means is connected is the router information storage. The warm start is performed when the information matches all router information stored in the means. As a result, when the power is turned off and then on again, it is possible to start up while reusing the initial setting information.

Further, the warm start means is acquired when the information about the subnetwork to which the communication means is connected does not match the router information stored in the router information storage means or via the subnetwork to which the communication means is connected. If all the router information thus obtained does not match all the router information stored in the router information storage means, the cold start may be performed without performing the warm start. As a result, when there is a possibility that a conflict occurs during a warm start, the system automatically shifts to a cold start, so that the router device can be prevented from starting up with a conflicting network configuration. .

  The present invention can be realized not only as such a network system, but also as a router device constituting the network system, as a router device activation method, or as a program incorporated in the router device. You can also Such a program can be downloaded to a router device or the like via a network.

  According to the present invention, when the upstream router device performs a cold start, the downstream router device also performs a cold start, so even if there is an abnormality in the network configuration in the network system, the abnormality Is automatically repaired, and if there is no net ID server, when the manually-configured router device performs a cold start, the manually-configured router updates all router information by incorporating its own information, and the network Since it is distributed to all routers existing in the system, the network configuration is automatically updated in the network system. Therefore, the practical value of the present invention in today where various communication networks are mixed is extremely high.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration example of a network system according to the present embodiment. This network system includes five subnets 30 to 34, four routers 10 to 13 connecting the subnets 30 to 34, a net ID server 1, and the like. Note that although various communication terminal devices called nodes are connected to each of the subnets 30 to 34, the illustration is omitted in this figure.

  The subnets 30 to 34 are home networks and the like, are the smallest units of the network, and are identified by the net ID. The node is a home appliance or the like that includes a communication interface.

  The routers 10 to 13 are apparatuses that connect two subnets of the same type or different types of transmission media, and route communication packets such as outputting a communication packet acquired from one subnet to the other subnet.

  The net ID server 1 is also called a parent router, and determines the net ID of each subnet 30 to 34 by providing a net ID to the routers 10 to 13 or provides various router information to the routers 10 to 13. It is a server device. The router information is information about the router and all the subnets to which the router is connected. The router information about the router (also referred to as “own router information”) and all the routers connected to the network system. With all router information.

In this network system, the following rules exist for the network configuration.
(1) The subnets 30 to 34 must be connected by the routers 10 to 13 so as to have a tree structure (that is, not to have a loop structure).
(2) For one network system, or when a plurality of network systems are integrated, one network system after integration (hereinafter, the network or the network system after integration is also referred to as “domain”) is 0. Alternatively, one net ID server is connected. When there are a plurality of subnets and a net ID server is connected, the net ID server needs to be connected to the most upstream (route) subnet.
(3) When a plurality of routers are connected to one subnet, a router on the route to the net ID server (that is, a router to which router information is first given by the net ID server in the subnet) One router exists, and the router becomes a “master router” in the subnet. Other routers become “slave routers”.

  In addition, when a plurality of routers are connected to one subnet, a router close to the net ID server on the communication path is referred to as a “router located upstream” and a router far from the net ID server. Is called “downstream router”. In the network system shown in FIG. 1, the router 11 and the router 12 are downstream routers when viewed from the router 10, and the router 10 is an upstream router when viewed from the router 11.

  FIG. 2 is a functional block diagram showing the configuration of the router 10 (11-13). The router 10 includes a first communication I / F unit 100, a second communication I / F unit 101, a control unit 102, and a router information storage unit 103.

  Each of the first communication I / F unit 100 and the second communication I / F unit 101 is a communication interface that connects the router 10 and the subnet. Under the control of the control unit 102, the communication packet flowing through the subnet is transmitted. Routing such as acquisition and transfer to the other communication I / F unit is performed.

  The control unit 102 is a CPU or the like that controls activation processing described later and the first communication I / F unit 100 and the second communication I / F unit 101 according to router information stored in the router information storage unit 103.

  The router information storage unit 103 is a memory or the like for storing information related to the router 10, all other routers in the domain, and the net ID server. The router information storage unit 104 stores the router information. And all router information storage unit 105 for holding all router information.

  The own router information storage unit 104 is connected to the first property storage unit 104 a for storing the attribute (property) of the subnet connected to the first communication I / F unit 100 and the second communication I / F unit 101. And a second property storage unit 104b for storing the attribute (property) of the subnet being set. As attributes stored in the first property storage unit 104a and the second property storage unit 104b, as shown in FIG. 3, the net ID of the corresponding subnet and the master router information in the subnet (the router is “master router”). Or “slave router”). For example, in FIG. 3, the first property storage unit 104a of the router 10 that connects the subnet A (net ID = 0x01) and the subnet B (net ID = 0x02) has 0x01 as the net ID for the subnet A. As router information, 0x4201 indicating a slave router is stored. On the other hand, the second property storage unit 104a stores 0x02 as a net ID and 0x4102 indicating a master router as master router information for the subnet B. An example is shown. The own router information storage unit 104 also has an area for storing the node ID of the router 10 (an identifier for uniquely identifying each node in the domain). “0x” is a symbol indicating that the subsequent numerical value is in hexadecimal notation. In the present embodiment, a router that connects two subnets is shown, but a router that connects three or more subnets may be used.

  The all router information storage unit 105 stores all router information, that is, a collection of the own router information of all other routers existing in the domain.

  Next, the startup process of the routers 10 to 13 in the network system configured as described above will be described.

First, the cold start of the routers 10 to 13 will be described.
The routers 10 to 13 perform startup processing different from that of general devices on each connected subnet. As the type of startup processing, the initial setting information such as the above properties is discarded, and a new initialization is performed, and initialization is performed while retaining the initial setting information acquired when the connection was established previously. There is a warm start to start.

  As a case where the routers 10 to 13 execute a cold start, (1) a new entry, (2) a warm start failure, and (3) a “net ID write request” ( In some cases, a request to update the net ID is received.

  In addition, the routers 10 to 13 functionally include an automatic setting router and a manual setting router, and the cold start procedure is different. Here, the automatic setting router is a router that automatically acquires a net ID from the net ID server 1, and the manual setting router is a router in which a user manually sets a net ID or a net ID is fixed. It is a router that holds it as a value. The router holds in the router information storage unit 103 whether it is an automatic configuration router or a manual configuration router. When there is a hardware switch or an input screen, it is possible to switch between the automatic setting router and the manual setting router by inputting either automatic setting or manual setting.

  First, a cold start of the routers 10 to 13 (hereinafter, such routers 10 to 13 are simply referred to as “automatic configuration routers”) when the routers 10 to 13 are automatic configuration routers will be described.

FIG. 4 is a table showing the activation conditions in the cold start of the automatic setting router. Here, a combination of the number of master routers detected in the connected subnet (“number of master routers detected”) and the status of whether or not communication with the net ID server 1 is possible (“communication with the net ID server”) For each (CASE 1 to 4), whether or not the automatic setting router is activated as a router is shown.

  As shown in this figure, the auto-configuration router has an abnormal situation, that is, (1) when 0 or 2 or more master routers are detected, and (2) its own router information from the net ID server. If all router information cannot be acquired, the router is not started. In other words, it is activated as a router only when only one master router is detected and communication with the net ID server is possible.

FIG. 5 is a diagram showing a basic sequence in a cold start of the automatic setting router.
First, the automatic setting router performs an internal initial process, and completes the setting of its own node ID (storage in its own router information storage unit 104) (S10). Then, in order to specify the number of master routers, the auto-configuration router sends a “master router information read request” (requests the router to provide master router information) for each of the subnets to which it is connected. Request) is transmitted by simultaneous broadcast within the subnet (S11). Thereafter, the master router information is acquired by receiving a “master router information read response” (response to the “master router information read request”) from the router (S12). As a result, the number of detected master routers is 0 or If it is determined that the number is 2 or more, the automatic setting router does not start as a router. In that case, it starts as a general node and does not perform the subsequent sequence.

  Subsequently, in order to obtain the current net ID of the subnet to be connected, the auto-configuration router is directed to the node profile (node connected to the subnet) for each of the subnets to which the self-configuration is connected. A “net ID read request” (request to notify the net ID) is transmitted by simultaneous broadcast within the subnet (S13). On the other hand, the automatic setting router also performs processing when receiving a direct message from another node having a net ID different from its own net ID. That is, the automatic setting router holds the net ID of the received “net ID read response” (response to “net ID read request”) as a temporary net ID (S14).

  Next, in order to specify the information including the number of net ID servers and the address of the net ID server, the automatic setting router makes a “net ID server information read request” (to the subnet in which the master router exists) ( A request for providing information such as properties to the net ID server) is transmitted by broadcast within the subnet (S15). Then, the automatic setting router acquires the net ID server information (S16), and as a result, when the number of detected net ID servers is found to be 0 or 2 or more, it does not start as a router. In that case, it starts as a general node and does not perform the subsequent sequence.

  Subsequently, the auto-configuration router sends an “all router information read request” (a request to provide all router information to the router) to the router profile for each subnet connected to itself. (S17). Then, all router information is acquired from routers existing in all subnets to which the automatically configured router that is executing a cold start is connected (S18).

After acquiring all the router information, the automatic setting router transmits a “registration request router information write request” (request for requesting new registration of router information to the net ID server) to the net ID server 1 (S19). In the EA information at the time of transmitting the “registration request router information write request” (EA is an address composed of an address determined by an address for realizing layer 2 communication in a transmission medium and an address for specifying a subnet) The slave router's net ID is a value acquired from a node profile existing in the subnet to which the slave router is connected, and the master router's net ID is 0x00. After transmitting this “registration request router information write request”, if it cannot receive the “own router information write request” (request to update to specified local router information) from the net ID server 1 within a certain time, Resend “registration request router information write request”. When other routers are registering with the net ID server, a router registration status notification (router registration busy status 0x30) is received from the net ID server. In this case, a registration request router information write request is issued after a certain time interval. Will be resent.

  When receiving the “own router information write request” from the net ID server 1 (S20), the automatic setting router sends a “own router information write response” to the net ID server 1 (notification that the own router information has been updated). Is transmitted (S21). After sending "Own router information write response", if "All router information write request" (request to update to all specified router information) cannot be received from the net ID server 1 within a certain time, "Register The request router information write request is retransmitted.

  When the “all router information write request” is received from the net ID server 1 (S22), the automatic setting router sends “all router information write response” to the net ID server 1 (notification that all router information has been updated). Is transmitted (S23). After sending "All router information write response", "Router registration completion notification" (notification that the network ID server has updated the router information) cannot be received from the network ID server 1 within a certain time. If the request is received, “registration request router information write request” is retransmitted.

  When the “router registration completion notification” is received from the net ID server 1 (S24), the automatic setting router sends a “router registration completion notification response” (notification that the “router registration completion notification” has been received) to the net ID. It transmits to the server 1 (S25). When the “router registration completion notification response” is transmitted to the net ID server 1, the automatic setting router starts to start as a router (S26).

  The self-configuration router is included in the “own router information write request” received from the net ID server 1 when all the router information acquired from other routers connected to the subnet to which the self-configuration is connected is the same. When the net ID is different from the net ID included in the “net ID read response” received from the node profile that exists in the subnet to which it is connected, it is broadcast in the subnet to the node profile that exists in the different subnet. A “net ID write request” is transmitted using the net ID acquired when the “own router information write request” received from the net ID server 1 is received. On the other hand, if all the router information acquired from other routers connected to the subnet to which it is connected is not the same, using the net ID acquired at the time of receiving the “own router information write request” received from the net ID server 1, A "net ID write request" is transmitted to the subnet to which the self router is connected and the master router does not exist by broadcast in the subnet.

  Such transmission of a “net ID write request” is an effective method for integrating two different network systems. If there is only a manually configured router, it can be established as a system even if there is no net ID server. However, if there is a net ID server in only one network system, the auto-configured router cold By implementing the start, the two network systems can be easily integrated.

FIG. 6 is a diagram illustrating an example in which two network systems are integrated by an automatic setting router. Here, an example in which the network system 20 and the network system 21 are integrated by the automatic setting router 14 is shown. The network system 20 has the net ID server 2, but the network system 21 has no net ID server. That is, the routers 15 and 16 connected to the network system 21 in which no net ID server exists are located downstream from the router 14 that executes the startup process.

  When the upstream router 14 performs a cold start, the downstream routers 15 and 16 are written with a net ID (receive a “net ID write request”) as described above, and start a cold start. That is, the downstream routers 15 and 16 always perform a cold start when the upstream router 14 performs a cold start. By such a cold start chain, the net ID is automatically assigned so that the net ID of the subnet is unique even after the integration of the network system.

  Next, a cold start of the routers 10 to 13 (hereinafter, such routers 10 to 13 are simply referred to as “manual setting routers”) when the routers 10 to 13 are manually set routers will be described.

  FIG. 7 is a table showing activation conditions in the cold start of the manually set router. Here, the number of master routers detected in the connected subnet (“master router detection number”), whether or not communication with the net ID server is possible (“communication with the net ID server”), and manual setting For each combination (CASE 1 to 5) with whether or not the net ID to be used is already used in the domain (“Duplicate NetID”), it is indicated whether or not the manually set router is activated as a router. .

  As shown in this figure, the manually set router has an abnormal situation, that is, (1) when two or more master routers are detected, and (2) the net ID to be set is within the domain. If it is used (if it is duplicated), it will not start as a router. In other words, (1) if no master router is detected, (2) if only one master router is detected, but communication with the net ID server is not possible, or (3) only one master router is detected. If the network ID server can communicate with the network ID but the network ID to be set is not used in the domain, the network ID server is activated as a router. Unlike automatic configuration routers, even if the master router is not detected or cannot communicate with the net ID server, it can be started as a router by constructing a simple network system such as connecting two subnets with one manual configuration router. This is because of considering the case. That is, since the manually set router holds the net ID to be set in advance, even if it cannot communicate with the net ID server, it performs a cold start as long as it is guaranteed that the net ID does not overlap within the domain. I am going to do that.

  FIG. 8 is a diagram showing a basic sequence in a cold start of a manually set router. As described above, the manual setting router starts the following sequence in a state where the net ID to be set is held in the first property storage unit 104a and the second property storage unit 104b in advance.

  First, the manually set router performs an internal initial process, and completes the setting of its own node ID (stored in its own router information storage unit 104) (S30). After that, the manually configured router sends a “master router information read request” to the router profile for each subnet connected to itself, in order to identify the number of master routers. Transmit (S31). Thereafter, the master router information is acquired by receiving a “master router information read response” (S33). As a result, when it is determined that the number of detected master routers is 2 or more, the router is not activated. In that case, it starts as a general node and does not perform the subsequent sequence.

  Further, when the net ID included in the received master router information is different from the net ID held by the manually set router, it does not start as a router. In other words, the following sequence is not performed, and the system is started as a general node, and an abnormality indicating that the system ID is different and the net ID is different is displayed. Also, as the occurrence of an abnormality, the content of the abnormality is notified by simultaneous broadcast within the domain.

  If no “master router information read response” is received (when the router does not exist in the subnet to which the router is connected), the manually set router starts as a router (S32a), and all subnets to which it is connected are started. A “net ID write request” is transmitted to the node profile by simultaneous broadcast within the subnet (S32b).

  When it is determined from the acquired master router information that one master router exists, the manually set router specifies information including the number of net ID servers, the presence / absence of a net ID server, and the address of the net ID server. Therefore, a “net ID server information read request” is transmitted by broadcast in the subnet to the subnet in which the master router exists (S34). Then, the net ID server information is acquired (S35). As a result, when the number of detected net ID servers is found to be 2 or more, the manually set router does not start as a router. In that case, it starts as a general node and does not perform the subsequent sequence. In this case, an abnormality indicating that two or more net ID servers have been detected is displayed, and the abnormality content is transmitted by simultaneous broadcast within the domain as an abnormality has occurred.

  Subsequently, the manually set router transmits an “all router information read request” to the router profile for each of all subnets to which it is connected (S36). Then, all router information is acquired from routers existing in all subnets to which the manually set router that is executing the cold start is connected (S37).

Thereafter, processing is divided according to whether the net ID server does not exist or not.
If there is no net ID server and the set net ID does not overlap with the net IDs of other subnets, the manually set router updates all router information based on its own EA and the acquired all router information. The "all router information write request" is transmitted to all routers existing in the domain (S38a). After transmission, start-up is started as a router (S38b).

  On the other hand, when the net ID server 1 exists, the manually set router acquires all router information (S37), and then transmits a “registration request router information write request” to the net ID server 1 (S39). At this time, in the EA information at the time of transmitting the “registration request router information write request”, both the net ID of the slave router and the net ID of the master router are set to self values.

When the “own router information write request” cannot be received from the net ID server 1 within a predetermined time after transmitting the “registration request router information write request”, the manually set router retransmits the “registration request router information write request”. When other routers are registering with the net ID server, a router registration status notification (router registration busy status 0x30) is received from the net ID server. In this case, a registration request router information write request is issued after a certain time interval. Will be resent.
When the “own router information write request” is received from the net ID server 1 (S40), the manually set router transmits a “own router information write response” to the net ID server 1 (S41). Also, make sure that the value written in “Request to write own router information” is the same as the manually set net ID. When a different net ID is written, the manually set router will start as a router. Instead, it starts as a general node and does not perform the subsequent sequence.

  If the “all router information write request” cannot be received from the net ID server 1 within a certain time after transmitting the “own router information write response”, the manually set router retransmits the “registration request router information write request”. When the “all router information write request” is received from the net ID server 1 (S42), the manually set router transmits an “all router information write response” to the net ID server 1 (S43). If the “router registration completion notification” is not received from the net ID server 1 from the net ID server 1 within a certain period of time after the “all router information write response” is transmitted, the manually set router sends a “registration request router information write request” "Will be resent. When the “router registration completion notification” is received from the net ID server 1 (S44), the manually set router transmits a “router registration completion notification response” to the net ID server 1 (S45). When the “router registration completion notification response” is transmitted to the net ID server 1, the manually set router starts to operate as a router.

  If all router information acquired in step S37 is not the same, the manually set router uses the net ID set by itself for the subnet to which it is connected and the master router does not exist. Send a “Net ID Write Request” by broadcast. As a result, network systems that are not connected to the net ID server can be connected.

  FIG. 9 is a diagram illustrating an example in which network systems to which a net ID server is not connected are integrated by a manually set router. Here, an example is shown in which the network system 22 having no net ID server and the network system 23 are integrated by the manual setting router 15.

  Note that the router 15 that has executed the cold start process acquires all router information from both integrated network systems, and updates all router information by adding its own router information to the acquired all router information. All the router information is distributed to all routers existing in the integrated network system. As a result, all router information held by all routers connected to the two network systems has the same contents.

Finally, a case where the routers 10 to 13 (in this case, the router 10 representatively) performs a warm start will be described below.
As a condition for the router 10 to perform the warm start, it is necessary that the router 10 has already entered the network once by executing the cold start. Note that during warm start processing, routing may or may not be executed based on the previously activated information.

  FIG. 10 is a table showing activation conditions in the warm start of the router. Here, the number of master routers detected in the connected subnet (“master router detection count”), whether the configuration of the connected subnet is the same as the previous startup (“connected subnet information”), the master Whether all router information acquired from the router or net ID server is the same as when it was last started ("all router information from the master router or net ID server"), and whether the router that performs a warm start is an auto-configuration router Whether it is a setting router (“automatic setting router OR manual setting router”) (CASE 1 to 7) for each combination (CASE 1 to 7), it is activated by any of the methods (A) to (C). It is shown. The process (A) is to start up with the information held before the warm start, the process (B) is not activated as a router, and the process (C) is not activated as a router. , To move to a cold start.

As shown in this figure, when an abnormal situation occurs, that is, (1) when two or more master routers are detected in the subnet connected to the router that performs warm start, (2) warm start When the master router is not detected in the subnet connected to the router that performs, and when it is an automatic configuration router, (3) the configuration of the subnet connected to the router that performs warm start is different from the previous startup And (4) if all router information acquired by the router that performs the warm start is different from the previous activation, the router is not activated. In other words, (1) when the master router is not detected, and the subnet configuration is the same as that at the previous activation and is a manually set router, or (2) only one master router is detected, If the subnet configuration is the same as when it was last activated and all the router information is the same as when it was last activated, it is activated as a router.

FIG. 11 is a diagram showing a basic sequence in the warm start of the router 10.
First, the router 10 performs an internal initial process, and completes the setting of its own node ID (stored in its own router information storage unit 104) (S50). After that, the router 10 sends a “master router information read request” to the router profile for all subnets to which the router 10 is connected in order to specify the number of master routers. (S51). Thereafter, the master router information is acquired by receiving the “master router information read response” (S52). As a result, when it is determined that the number of detected master routers is 2 or more, the router does not start. In that case, it starts as a general node and does not perform the subsequent sequence.

  When it is determined from the acquired master router information that the number of master routers is 0 or 1, the router 10 subsequently obtains the current net ID of the connected subnet with respect to the connected subnet. , "Net ID read request" is transmitted by simultaneous broadcast within the subnet (S53). Then, the net ID is acquired (S54), and by referring to the own router information storage unit 104 from the acquired net ID value, it is compared with the subnet configuration at the time of previous activation, and as a result, they are found to be different. To the router cold start. If the number of detected master routers is 0 and the subnet configuration is the same as the previous activation, the router is activated as a router under the previously activated conditions.

  If only one master router is detected, the router 10 sends a “net ID server information read request” to the subnet in which the master router exists in order to specify the number of net ID servers. It is transmitted by simultaneous broadcast (S55). Then, the server receives the net ID server information (S56), refers to the router information storage unit 103, compares the received net ID server information with the net ID server information at the previous activation, and as a result, they are different. If it is found, the router 10 shifts to cold start.

  Subsequently, when there is a net ID server, the router individually transmits an “all router information read request” to the net ID server 1 (S57), whereas when the net ID server 1 does not exist. In step S58, an “all router information read request” is transmitted to the master router in a simultaneous broadcast within the subnet. Then, all router information is acquired (S59, S60) and compared with all router information held in all router information storage unit 105. As a result, when it is found that the acquired all router information is different from all the router information at the previous activation, the router 10 shifts to cold start. Also, even when the acquired all router information does not include its own EA, the router 10 shifts to cold start. If all the router information is the same as the previous activation information and the own EA is included in the all router information, the router 10 starts activation as a router (S61).

In this way, the router 10 starts as a warm start only when it can be confirmed that the configuration of the connected subnet and all the router information are the same as those at the previous startup, and as otherwise, as a router. Does not start or moves to cold start. This prevents the router from starting up with inconsistency that the initial setting information held at the time of previous activation does not reflect the current network configuration.

The network system according to the present invention has been described based on the embodiment, but the present invention is not limited to this embodiment.
For example, in this embodiment, the routers 10 to 13 connect two subnets, but may have a function of connecting three or more subnets.

  Further, as a method of storing the net ID set by the manually setting router, not only a method of storing in a IC such as a memory but also a method of setting by a dip switch or the like may be used.

  The present invention relates to a network system and a router device in which a plurality of networks are connected via a router device. For example, a network system including various transmission media such as a coaxial LAN cable, a power line, an infrared ray, and a radio, and those transmission media. It can be used as a router device such as a gateway to be connected.

It is a figure which shows the structural example of the network system in embodiment of this invention. It is a functional block diagram which shows the structure of a router. It is a figure which shows the example of the property memorize | stored in a router. It is a table which shows the starting conditions in the cold start of an automatic setting router. It is a figure which shows the basic sequence in the cold start of an automatic setting router. It is a figure which shows the example by which two network systems are integrated by the automatic setting router. It is a table which shows the starting conditions in the cold start of a manually set router. It is a figure which shows the basic sequence in the cold start of a manual setting router. It is a figure which shows the example in which network systems without a net ID server are integrated by a manual setting router. It is a table which shows the starting conditions in the warm start of a router. It is a figure which shows the basic sequence in the warm start of a router.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Net ID server 10-16 Router 20-23 Network system 30-34 Subnet 100 1st communication I / F part 101 2nd communication I / F part 102 Control part 103 Router information storage part 104 Self-router information storage part 104a First property storage unit 104b Second property storage unit 105 All router information storage unit