Source: http://www.google.com/patents/US20020159448?dq=7800613
Timestamp: 2017-08-18 22:45:06
Document Index: 288264966

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Patent US20020159448 - Communication device and method of controlling the same - Google Patents
A communication device includes a first part transmitting information to and receiving information from an adjacent device, a second part managing address information of all mounting ports of the communication device, a first port of the adjacent device, and a network to be constructed, the first port...http://www.google.com/patents/US20020159448?utm_source=gb-gplus-sharePatent US20020159448 - Communication device and method of controlling the same
Publication number US20020159448 A1
Application number US 09/957,141
Also published as US7245618
Publication number 09957141, 957141, US 2002/0159448 A1, US 2002/159448 A1, US 20020159448 A1, US 20020159448A1, US 2002159448 A1, US 2002159448A1, US-A1-20020159448, US-A1-2002159448, US2002/0159448A1, US2002/159448A1, US20020159448 A1, US20020159448A1, US2002159448 A1, US2002159448A1
Inventors Yuji Ito, Noritake Izaiku
Original Assignee Yuji Ito, Noritake Izaiku
Communication device and method of controlling the same
US 20020159448 A1
A communication device includes a first part transmitting information to and receiving information from an adjacent device, a second part managing address information of all mounting ports of the communication device, a first port of the adjacent device, and a network to be constructed, the first port being connected to the communication device, a third part automatically determining addresses for the mounting ports of the communication device and the first port of the adjacent device so that the addresses are not duplicated; and a fourth part managing address determination authority to determine the addresses.
a second part managing address information of all mounting ports of the communication device, a first port of the adjacent device, and a network to be constructed, the first port being connected to the communication device;
a third part automatically determining addresses for the mounting ports of the communication device and the first port of the adjacent device so that the addresses are not duplicated; and
a fourth part managing address determination authority to determine the addresses.
2. The communication device as claimed in claim 1, further comprising a fifth part automatically selecting an unused one from addresses on a network including a port to which a terminal is connected, the port being one of the mounting ports of the communication device or a second port of the adjacent device.
3. The communication device as claimed in claim 2, further comprising a sixth part selecting one of the communication device and the adjacent device as a managing device performing centralized management of addresses of terminals on the network,
4. The communication device as claimed in claim 1, further comprising a fifth part resetting the addresses if the addresses are exhausted.
5. The communication device as claimed in claim 1, further comprising a fifth part determining addresses for connecting the network constructed by dynamic address assignment and an existing network constructed by static address assignment based on configuration information.
6. The communication device as claimed in claim 1, further comprising a fifth part constructing configuration information of the communication device based on configuration information including address information preset for the mounting ports.
7. The communication device as claimed in claim 1, further comprising a fifth part controlling a defect of one of the communication device and the adjacent device which one manages the address determination authority.
8. The communication device as claimed in claim 1, further comprising a fifth part selecting one of the communication device and the adjacent device as a device performing centralized management of addresses of terminals on the network.
9. A communication device control method comprising the step of:
(a) determining automatically addresses for all mounting ports of a communication device having address determination authority to determine the addresses and a first port of an adjacent device connected to the communication device through the first port so that the addresses are not duplicated,
wherein address information of the mounting ports of the communication device, the first port the adjacent device, and a network to be constructed is managed, the network including the communication device and the adjacent device.
10. The method as claimed in claim 9, further comprising the step of (b) selecting automatically an unused one from addresses on a network including a port to which a terminal is connected, the port being one of the mounting ports of the communication device or a second port of the adjacent device.
11. The method as claimed in claim 10, further comprising the step of (c) selecting one of the communication device and the adjacent device as a managing device performing centralized management of addresses of terminals on the network,
wherein said step (b) sets a DHCP server function in the communication device if said step (c) selects the communication device as the managing device and said step (c) establishes tunnel connection to the adjacent device if said step (c) selects the adjacent device as the managing device.
12. The method as claimed in claim 9, wherein said step (a) comprises the step of (b) resetting the addresses if the addresses are exhausted.
13. The method as claimed in claim 9, wherein said step (a) comprises the step of (b) determining addresses for connecting the network constructed by dynamic address assignment and an existing network constructed by static address assignment based on configuration information.
14. The method as claimed in claim 9, wherein said step (a) comprises the step of (b) constructing configuration information of the communication device based on configuration information including address information preset for the mounting ports.
15. The method as claimed in claim 9, wherein said step (a) comprises the step of (b) controlling a defect of one of the communication device and the adjacent device which one manages the address determination authority.
16. The method as claimed in claim 9, further comprising the step of (b) selecting one of the communication device and the adjacent device as a device performing centralized management of addresses of terminals on the network.
It is a general object of the present invention to provide a communication device and a method of controlling the same in which the above-described disadvantage is eliminated.
[0015]FIG. 1 is a diagram showing a principle of the present invention;
[0016]FIG. 2 is a block diagram showing a structure of a network including communication devices according to a first embodiment of the present invention;
[0017]FIGS. 3 through 10 are diagrams showing a communication sequence on the network of FIG. 2;
[0018]FIG. 11 is a diagram showing address information concerning the network of FIG. 2;
[0019]FIGS. 12 and 13 are diagrams showing signal frame formats employed in the first and other embodiments of the present invention;
[0020]FIG. 14 is a diagram showing a communication sequence on a network including communication devices according to a second embodiment of the present invention;
[0021]FIG. 15 is a block diagram showing a structure of a network including communication devices according to a third embodiment of the present invention;
[0022]FIGS. 16 and 17 are diagrams showing a communication sequence on the network of FIG. 15;
[0023]FIG. 18 is a diagram showing address information employed in a fourth embodiment of the present invention;
[0024]FIG. 19 is a diagram showing a communication sequence on a network including communication devices according to a fifth embodiment of the present invention;
[0025]FIG. 20 is a diagram showing a communication sequence on a network including communication devices according to a sixth embodiment of the present invention;
[0026]FIG. 21 is a diagram showing a case where a DHCP server function is set in each router; and
[0027]FIG. 22 is a diagram showing a case where centralized management is performed on a DHCP server function.
[0029]FIG. 1 is a block diagram showing a structure of a communication device 100 based on the principle of the present invention. In the drawing, parts newly introduced in the present invention to a conventional communication device are indicated by blocks formed by double lines.
[0055]FIG. 2 is a block diagram showing a structure of a network to which the present invention is applied. This network is an IP network including terminals T1 and T4 and routers R1 through R4. Hereinafter, a terminal is referred to by Tn where n indicates a terminal identification number. Further, a router and its port are referred to by RxPy where x indicates a router identification number and y indicates a port number. For instance, the router R3 includes four ports of R3P1, R3P2, R3P3, and R3P4. Each of the routers R1 through R4 has the structure of the communication device 100 of FIG. 1.
In FIG. 3, when the routers R1, R2, R3, and R4 are turned on in the order described, each of the routers R1 through R4 has its address determination part 2 cause the adjacent router communication part 1 to successively transmit a “parent router inquiry request” to all its mounting ports by MAC broadcast so as to determine whether its adjacent devices (routers) are in compliance with the present invention.
On receiving the “parent router inquiry request”, each of the routers R1 through R4 has its adjacent router communication part 1 inform the address determination part 2 of the reception of the request.
Each of the routers R1 through R4 has its address determination part 2 edit parent router information under its own management and has its adjacent router communication part 1 transmit a “parent router inquiry response”.
On receiving the “parent router inquiry response”, each of the routers R1 through R4 has its adjacent router communication part 1 inform the address determination part 2 of the reception of the response.
In step S6, the address determination part 2 of the parent router R1 causes the adjacent router communication part 1 to transmit a “subordinate device detection request” to all the mounting ports of the parent router R1 by MAC broadcast. The adjacent router communication part 1 of each of the routers R2 and R3 transmits the received “subordinate device detection request” to the address determination part 2. The address determination part 2 of each of the routers R2 and R3 checks the contents of the received information and the setting information of a mounting port that has received the request. Since the mounting port is not assigned an address, the address determination part 2 edits an IP address setting condition (no address) and causes the adjacent router communication part 1 to transmit a “subordinate device detection response” to the parent router R1.
In step S7, the adjacent router communication part 1 of the parent router R1 notifies the address determination part 2 of the received “subordinate device detection responses”. Through the received information, the address determination part 2 recognizes the devices without addresses (the routers R2 and R3). Then, with respect to each of the routers R2 and R3, the address determination part 2 selects one of IP addresses on a network including a port to which a corresponding one of the routers R2 and R3 is connected and notifies the address management part 3 of the addresses. At the same time, the address determination part 2 of the parent router R1 causes the adjacent router communication part 1 to transmit a “subordinate device setting request” to each of the routers R2 and R3 to request the corresponding port of each of the routers R2 and R3 to set the IP address.
In step S8, the adjacent router communication part 1 of each of the routers R2 and R3 transmits the received “subordinate device setting request” to the address determination part 2. The address determination part 2 sets the IP address for the mounting port that has received this request based on the received information and notifies the address management part 3 of the IP address. The address determination part 2 requests the terminal address determination part 5 to set the DHCP function for each port. Then, the address determination part 2 causes the adjacent router communication part 1 to transmit a “subordinate device setting response” to the parent router R1 (step S7).
In step S9, the adjacent router communication part 1 of the parent router R1 transmits the received “subordinate device setting responses” to the address determination part 2 of the parent router R1. The address determination part 2 causes the address determination authority management part 4 to release the address determination authority.
In step S10 of FIG. 5, each of the routers R2 and R3 causes its address determination part 2 to transmit an “address determination authority acquisition request” to the parent router R1 via a routing control part 12 of each of the routers R2 and R3 to perform an address determination authority acquisition operation if at least one of its ports is assigned an IP address and a port without an IP address is detected. In this embodiment, the router R2 transmits the request earlier than the router R3.
The parent router R1 has the “address determination authority acquisition request” received via a frame transmission and reception part 11 and transmitted to the address determination authority management part 4.
In step S11, the address determination authority management part 4 of the parent router R1 checks the acquisition state of the address determination authority. If the address determination authority is not acquired, the address determination authority management part 4 changes the state to an acquired state and thereafter, transmits an “address determination authority acquisition response” (acquisition authorized) to the router R2 via the routing control part 12. In step S12, in response to the acquisition request from the router 3, the address determination authority management part 4 transmits an “address determination authority acquisition response” (acquisition unauthorized) to the router R3 via the routing control part 12 since the address determination authority has been acquired by the router R2.
The router R2 has the “address determination authority acquisition response” (acquisition authorized) received via the frame transmission and reception part 11 and transmitted to the address determination part 2.
In step S13, the address determination part 2 of the router R2 requests the transmission of the latest address information by transmitting an “address information transmission request” to the parent router R1 via the routing control part 12.
In step S14, the parent router R1 has the “address information transmission request” received via the frame transmission and reception part 11 and transmitted to the address management part 3. The address management part 3 of the parent router R1 transmits all the latest address information to the router R2 via the routing control part 12 as an “address information transmission response”.
The router R3 has the “address determination authority acquisition response” (acquisition unauthorized) received via the routing control part 12 and transmitted to the address determination part 2. The address determination part 2 repeats the above-described operation periodically while the router R3 has a mounting port without an IP address.
In steps S16 R3, S16 R4, and S16 R1 of FIGS. 5 and 6, the address determination part 2 of the router R2 causes the adjacent router communication part 1 to transmit a “subordinate device detection request” to all the port of the router R2.
The adjacent router communication part 1 of each of the routers R3 and R4 has the received “subordinate device detection request” transmitted to the address determination part 2.
In step S17 R3, the address determination part 2 of the router R3 checks the contents of the received information and the setting information of a mounting port that has received the request. Since the mounting port is not assigned an address, the address determination part 2 edits an IP address setting condition (no address) and causes the adjacent router communication part 1 to transmit a “subordinate device detection response” to the router R2.
In step S18 of FIG. 6, the address determination part 2 of the router R4 checks the contents of the received information and the setting information of a mounting port that has received the request. Since the mounting port is assigned with an IP address, the address determination part 2 performs a parent router priority check. In step S 19, the address determination part 2 determines that the router R1 is a parent router having a higher priority than the router R4 and that the router R4 is the only device on a network including the router R4, and initializes the address information of the router R4. Thereafter, the address determination part 2 edits an IP address setting condition (no address). Then, in step S17 R4, the address determination part 2 of the router R4 causes the adjacent router communication part 1 to transmit a “subordinate device detection response” to the router R2. It is assumed that the router R4 is in operation as a parent router.
In step S20, through the received information, the address determination part 2 of the router R2 recognizes the devices having ports without addresses (the routers R3 and R4). Then, with respect to each of the routers R3 and R4, the address determination part 2 selects one of IP addresses on a network including a port to which a corresponding one of the routers R3 and R4 is connected and notifies the address management part 3 of the addresses. At the same time, the address determination part 2 of the router R2 causes the adjacent router communication part 1 to transmit a “subordinate device setting request” to each of the routers R3 and R4 to request the corresponding port of each of the routers R3 and R4 to set the IP address.
In step S21, the adjacent router communication part 1 of each of the routers R3 and R4 transmits the received “subordinate device setting request” to the address determination part 2. The address determination part 2 sets the IP address for the mounting port that has received this request based on the received information and notifies the address management part 3 of the IP address. The address determination part 2 requests the terminal address determination part 5 to set the DHCP function for each port. In step S22, the address determination part 2 of each of the routers R3 and R4 causes the adjacent router communication part 1 to transmit a “subordinate device setting response” to the router R2.
The adjacent router communication part 1 of the router R2 transmits the received “subordinate device setting responses” to the address determination part 2. In step S23, the address determination part 2 of the router R2 completes the setting of the IP addresses for all the mounting ports of the router R2 and the adjacent devices complying with the present invention, and thereafter, in step S24, updates the address information by transmitting the latest address information to the parent router R1 via the routing control part 12 as an “address information update notice”.
The parent router R1 transmits the “address information update notice” received via the frame transmission and reception part 11 to the address management part 3. In step S25, the address management part 3 of the parent router R1 updates the address information under its own management based on the received address information, and in step S26, transmits an “address information update response” to the router R2 via the routing control part 12.
In step S27 of FIG. 7, the router R2 transmits the “address information update response” received via the frame transmission and reception part 11 to the address determination part 2. The address determination part 2 of the router R2 transmits an “address determination authority acquisition release request” to the parent router R1 via the routing control part 12.
In step S28, the parent router R1 transmits the “address determination authority acquisition release request” received via the frame transmission and reception part 11 to the address determination authority management part 4. The address determination authority management part 4 of the parent router R1 releases the acquisition of the address determination authority. The parent router R1 transmits an “address determination acquisition release response” to the router R2 via the routing control part 12.
In step S29, the address management part 3 of the parent router R1 causes the address determination authority management part 4 to acquire the address determination authority for the parent router R1 and transmits, as “address information transfer notices”, the latest address information via the routing control part 12 to the routers R2 and R3 that are the devices complying with the present invention and registered based on the address information.
In step S30, each of the routers R2 and R3 transmits the “address information transfer notice” received via the frame transmission and reception part 11 to the address management part 3. The address management part 3 of each of the routers R2 and R3 updates the address information of each of the routers R2 and R3 based on the received address information, and transmits an “address information transfer response” to the parent router R1 via the routing control part 12.
[0089]FIGS. 12 and 13 are diagrams showing signal frame formats employed in the above-described sequence. The frame format shown in FIG. 12 includes a destination MAC address, a sender MAC address, a protocol, and a data part. The data part consists of a control part and an information part. Each of the parent router inquiry request, the parent router inquiry response, the subordinate device detection request, the subordinate device detection response, the subordinate device setting request, and the subordinate device setting response is a signal having this frame format. Information for identifying these signals is written to the control part of the data part. The information part of each signal is recorded with information show in FIG. 12. The parent router inquiry request, for instance, has its information part recorded with a device-representative MAC address.
In FIG. 14, when the address determination part 2 of the router R4 detects a shortage of network addresses at the time of network address determination (step S41), the address determination part 2 activates the address reset part 9. When the address determination part 2 calls the address reset part 9, in step S42, the address reset part 9 calculates the number of residual operable ports of the router R4 which ports are not assigned network addresses, and in step S43, transmits an “address exhaustion notice” to the parent router R1 via the routing control part 12.
In step S44, the parent router R1 has the “address exhaustion notice” received by its frame transmission and reception part 11 and transmitted to its address determination part 2. At this time, the address determination part 2 recognizes the number of residual ports of the router R4 in the frames of the “address exhaustion notice”. Next, the address determination part 2 transmits an “address exhaustion response” to the router R4 via the routing control part 12.
In step S45, on receiving the “address exhaustion response” from the parent router R1 by its frame transmission and reception part 11, the router R4 resumes the operation from a response-awaiting state. In step S46, the router R4 transmits an “address determination authority acquisition release request” to the parent router R1 via the routing control part 12 since the router R4 has acquired the address determination authority.
In step S47, the parent router R1 has the “address determination authority acquisition release request” from the router R4 received by its frame transmission and reception part 11 and transmitted to the address determination authority management part 4, thereby releasing the address determination authority acquired by the router R4. Next, in step S48, the address determination authority management part 4 of the parent router R1 transmits an “address determination authority acquisition release response” to the router R4 via the routing control part 12.
The router R4 has the “address determination authority acquisition release response” received by its frame transmission and reception part 11 and transmitted to its address determination part 2.
In step S49, after the “address determination authority acquisition release response” being transmitted to the router R4, the address determination part 2 of the parent router R1 extends a subnet mask width that is provided based on the number of residual ports required by the router R4. In step S50, the parent router R1 transmits “address reset notices” to the routers R2 through R4 via the routing control part 12 so as to reset addresses for all the ports of the parent router R1 and all of the routers R2 through R4.
On the other hand, each of the routers R2 through R4 has the “address reset notice” received via the frame transmission and reception part 11 and transmitted to the address determination part 2, and waits until a “subordinate device detection request” is transmitted from the parent router R1.
[0105]FIG. 15 is a block diagram showing a structure of a network to which the third embodiment of the present invention is applied. The network of FIG. 15 is formed by connecting an existing network to a port R4P4 of the router R4 of the network shown in FIG. 2. Characteristically, network addresses can be determined automatically in such a case in the third embodiment. The existing network illustrated in FIG. 15 includes a router R5 and a terminal T5 such as a DHCP server.
[0106]FIGS. 16 and 17 are diagrams showing a sequence of operations for automatically determining network addresses according to the third embodiment. In step S51 of FIG. 16, when the router R4 detects a linkup of the existing network to its mounting port (R4P4), the address determination part 2 of the router R4 causes the adjacent router communication part 1 to transmit a “parent router inquiry request” to the port by MAC broadcast.
If no “parent router inquiry response” is returned from the port, it is determined that no device complying with the present invention exists. In step S52, this determination result is transmitted to the existing network connection part 8, and a DHCP frame is transmitted to the DHCP server T5. In step S53, the router R4 detects the router R5 on the existing network by receiving a DHCP frame from the DHCP server T5 by its frame transmission and reception part 11 and transmitting the DHCP frame to its existing network connection part 8. In step S54, the router R4 broadcasts an “IP address acquisition request” to the network connected to the port and receives “IP address acquisition responses”. Then, in step S55, the router R4 constructs IP addresses included in the DHCP frames as a logically different network.
In step S56, in order to obtain path information from the detected router R5, the existing network connection part 8 of the router R4 transmits a “path information request” to the router R5 via the routing control part 12. The router R5 returns a “path information response” to the router R4. This response is transmitted to the existing network connection part 8 of the router R4 via the frame transmission and reception part 11 thereof. The above-described operation is repeated so as to obtain all the path information from the router R5.
If there is a duplicated network address, in step S58, the existing network connection part 8 of the router R4 transmits an “address determination authority management authority request” to the parent router R1 via the routing control part 12. This request is transmitted to via the frame transmission and reception part 11 of the parent router R1 to the address determination authority management part 4 thereof so that, in step S59, an “address determination authority management authority response” is transmitted via the routing control part 12 to the router R4.
In step S60 of FIG. 17, the frame transmission and reception part 11 of the router R4 receives the “address determination authority management authority response” and transmits the response to the existing network connection part 8. Thereby, the router R4 acquires the address determination authority. Thereafter, in step S64, the router R4 transmits an “all network addresses change notice” to the routers R1 through R3 via the routing control part 12. Prior to this, in step S61, the existing network connection part 8 of the router R4 informs the address management part 3 thereof of the change of all the network addresses. In response to this, the address management part 3 of the router 4 initializes all the network address information generated on the networks of the devices having the structure of the communication device 100 of the present invention and develops the path information acquired from the router 5 and the address assigned to the port connected to the existing network. In step S62, the address management part 3 assigns addresses not included in the developed address information to the ports of the router 4 the addresses of which port are undecided. In step S63, the router 4 temporarily has the highest device priority and releases the address determination authority.
On the other hand, in step S64, each of the routers R1 through R3 has the “all network addresses change notice” transmitted to its address determination part 2 via its frame transmission and reception part 11. In step S65, each of the routers R1 through R3 holds the address of the next parent router R4 and waits for a “subordinate device detection request”. Thereafter, in step S65, each of the routers R1 through R3 sets its own ports by the same operations as in the first embodiment.
Next, in step S65A, the existing network connection part 8 of the router R4 returns the device priority of the router R4 from the highest to its original state and in step S66, transmits an “address information update notice” to the routers R1 through R3 via the routing control part 12. In step S67, each of the routers R1 through R3 transmits the received “address information update notice” to its address determination part 2 via its frame transmission and reception part 11 so that the priority of the router R4 is returned to its original state. Thereafter, in step S68, each of the routers R1 through R3 transmits an “address information update response” to the router R4 via the routing control part 12.
The router R4 has the “address information update response” from each of the routers R1 through R3 received by its frame transmission and reception part 11 and transmitted to the existing network connection part 8 so as to release the address determination authority that has been held by the router 4.
[0118]FIG. 18 is a diagram showing address information employed in the fourth embodiment. A network structure is equal to that shown in FIG. 2. A port R1P1 of the router R1 complies with predetermined configuration information. When a device having the structure of the communication device 100 of the present invention, such as the router 1, is turned on, the configuration development part 10 of the device reads configuration information from the configuration storage part 13 and constructs a system based on the configuration information. When the configuration development part 10 detects configuration information related to the address determination part 2, the configuration development part 10 posts the detection to the address determination part 2, thereby constructing a network reflecting the predetermined network address information.
In step S71 of FIG. 19, the router defect control part 7 of each of the routers R2 through R4 transmits a “health check request” to the parent router R1 via the frame transmission and reception part 11. In step S72, the parent router R1 has the “health check request” transmitted via its frame transmission and reception part 11 to its router defect control part 7. The router defect control part 7 of the parent router R1 transmits a “health check response” to each of the routers R2 through R4 via the routing control part 12. The router defect control part 7 of each of the routers R2 through R4 receives the “health check response” via the frame transmission and reception part 11 to confirm that the parent router R1 is in normal operation. This operation is periodically performed so as to confirm whether the parent router R1 is in normal operation.
At this point, if the parent router R1 becomes inoperative (step S73), the following operations are performed with the router defect control part 7 of the router 2 sensing that the “health check response” is not returned to each of the routers R2 through R4 (step S74).
In step S75, in order to confirm the existence of a router currently holding the address determination authority, the router defect control part 7 of the router R2 requests the address management part 3 to transmit an “authority information collection request” to each of the routers R3 and R4 via the routing control part 12. In step S78, the address determination authority management part 4 of each of the routers R3 and R4 receives the “authority information collection request” via the frame transmission and reception part 11. At this point, when the router defect control part 7 of the router R4 receives the “authority information collection request” via the frame transmission and reception part 11, the router defect control part 7 inquires of the address determination authority management part 4 of the router R4 whether the router R4 holds the address determination authority. Since the router R4 does not hold the address determination authority, the router defect control part 7 transmits an “authority information collection response” to the router R2 via the routing control part 12, noting that the router R4 does not hold the address determination authority.
On the other hand, in step S76, when the router defect control part 7 of the router R3 receives the “authority information collection request” via the frame transmission and reception part 11, the router defect control part 7 inquires of the address determination authority management part 4 of the router R3 whether the router R3 holds the address determination authority. However, since the router R3 is currently under an update operation, update information is first transmitted to each of the routers R2 and R4 after the update operation is terminated. Then, in step S77, the router defect control part 7 transmits an “authority information collection response” to the router R2 via the routing control part 12, noting that the router R3 holds the address determination authority.
In step S79, the frame transmission and reception part 11 of the router R2 transmits each received “authority information collection response” to the router defect control part 7 to detect the routers R3 and R4 that are ready for communication. The router defect control part 7 of the router R2 recognizes from the previously acquired address information that the next parent router candidate is the router R4. In step S80, the router defect control part 7 transmits a “next parent router request” to the router R4 via the routing control part 12.
In step S81, the router R4 has the “next parent router request” received by its frame transmission and reception part 11 and transmitted to the address determination authority management part 4 via the router defect control part 7. The router R4 recognizes that the next parent router candidate is the router R4. In step S82, the next parent router R4 acquires the address determination authority for itself and, in step S83, updates parent router information through the address management part 3. In step S84, the next parent router R4 returns a “next parent router response” to the router R2 via the routing control part 12.
In step S85, the next parent router R4 transmits a “parent router change request” to each of the routers R2 and R3 via the routing control part 12 with the parent router information updated by the address determination authority management part 4 being added to the request.
In step S86, each of the routers R2 and R3 has the “parent router change request” received via its frame transmission and reception part 11 and transmitted to its address determination authority management part 4. The address determination authority management part 4 recognizes the router R4 as a parent router. Further, in step S87, the address determination authority management part 4 informs the address management part 3 that the parent router is the router R4 to update the address information. In step S88, the address determination authority management part 4 transmits a “parent router change response” to the router R4 via the routing control part 12.
The next parent router R4 has the “parent router change response” from each of the routers R2 and R3 received by its frame transmission and reception part 11 and transmitted to its address determination authority management part 4, thereby terminating the operation.
[0135]FIG. 20 is a diagram showing an operation sequence according to the sixth embodiment of the present invention. After the parent router R1 is turned on in step S90, in step S91, the configuration development part 10 of the parent router R1 notifies the terminal address determining device determination part 6 of terminal address setting conditions. The terminal address determining device determination part 6 recognizes a designation as an integration function for terminal address determination by configuration development. The address management part 3 enters the contents of the transmitted setting conditions in the address information.
In step S92, the router R1 transmits a “parent router inquiry request” to each of the adjacent terminal T1 and the routers R2 and R3, and receives a “parent router inquiry response” from each of the adjacent terminal T1 and the routers R2 and R3. Thereafter, in step S93, the router R1 performs the same operations as in steps S3 through S5 of FIG. 4. Then, in step S94, the router R1 transmits a “subordinate device detection request” to each of the adjacent terminal T1 and the routers R2 and R3, and receives a “subordinate device detection response” from each of the adjacent terminal T1 and the routers R2 and R3. Since each of the responses from the routers R2 and R3 lacks an address, the router R1 transmits a “subordinate device setting request” (address setting and designation as a DHCP-shared router) to the router R2 and receives a “subordinate device setting response” therefrom.
In step S95, the address determination part 2 of the router R2 receives the “subordinate device setting request” and requests the terminal address determination part 5 to set a DHCP function for each of the ports of the router 2. The terminal address determination part 5 judges the contents of the received information so as to be prevented from setting the DHCP function. Instead, the terminal address determination part 5 requests the terminal address determining device determination part 6 to establish tunnel connection to the parent router R1.
[0138]FIG. 21 is a diagram showing a case where a DHCP server function is set in each of the routers R1 through R4. This corresponds to setting functions in step S8 of FIG. 4 and step S21 of FIG. 6. Each of the routers R1 through R4 has the network addresses of its ports set by its DHCP server function.
[0139]FIG. 22 is a diagram showing a case where centralized management is performed on a DHCP server function. In this case, the router R2 performs the centralized management of the DHCP function. That is, the router R2 set network addresses for all the ports of the routers R1 through R4. This operation corresponds to the operation of step S95 of FIG. 20.
International Classification H04L12/70, H04L29/12, H04L12/46, H04L12/28
Cooperative Classification H04L29/12009, H04L29/12924, H04L61/6063
European Classification H04L61/60D60, H04L29/12A, H04L29/12A9D60
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ITO, YUJI;IZAIKU, NORITAKE;REEL/FRAME:012202/0648