Communication Network Management Method, Access Router, And Mobile Communication Device
Disclosed is a technique which reduces or omits the time needed for DAD processing solicited when a mobile communication device establishes a connection with a new subnetwork, thereby reducing the packet loss and delay to improve the communication efficiency. According to this technique, in a network in which a plurality of ARs 11 to 14 exist, when a mobile communication device (MN 10 ) establishes a connection with one of these plurality of ARs, in addition to the implementation of the DAD processing for confirming whether or not the address (CoA) of the MN is usable at the connection-accepting side, a wide-range DAD implementation request message including the interface ID of the MN is transmitted from the connection-accepting side AR to the other AR existing in a network of a given range (wide-range DAD effective area 31 ), and in a subnetwork under each of ARs, the DAD processing is conducted so as to confirm whether or not the address at the connection of the MN is usable. This enables the DAD processing to be omitted when the MN moves to the other subnetwork.
1 . A communication network management method for a communication system including a plurality of access routers and a mobile communication device connectable to a subnetwork under management of each of said plurality of access routers, comprising:
a step in which, when said mobile communication device establishes a connection with one of said plurality of access routers, said mobile communication device transmits a message for confirming the uniqueness of an address to be used in a subnetwork under the management of said access router which is an object of connection, to an arbitrary node in said subnetwork under the management of said access router with which said mobile communication device establishes the connection;
a step in which said access router which has received the message and with which said mobile communication device establishes the connection transmits a request message, which makes a request for confirming the uniqueness of an address to be used when said mobile communication device establishes a connection with the other access router in said subnetwork under the management of the other access router, to the other access router; and
a step in which, upon receipt of the request message from said access router with which said mobile communication device establishes the connection, the other access router confirms the uniqueness of the address, which is used by said mobile communication device, in said subnetwork under the management of the other access router.
2 . The communication network management method according to claim 1 , comprising:
a step of, when a result of the confirmation on the uniqueness of the address, which is used by said mobile communication device, in the other access router shows that the address is unusable because of being in a duplicate state, transmitting, to said access router with which said mobile communication device establishes the connection, an address duplicate notification message for notifying that the address is unusable; and
a step in which said access router which has received the address duplicate notification message from the other access router and with which said mobile communication device establishes the connection transmits an unusable-state notification message for the notification of the unusable-state of the address, which is used when said mobile communication device establishes the connection with the other access router in said subnetwork under the management of the other access router, to said mobile communication device.
3 . The communication network management method according to claim 2 , comprising:
a step of, when a result of the confirmation on the uniqueness of the address, which is used by said mobile communication device, in the other access router shows the uniqueness of the address, transmitting, to said access router with which said mobile communication device establishes the connection, an address confirmation notification message for notifying that the address is usable; and
a step in which said access router which has received the address confirmation notification message from the other access router and with which said mobile communication device establishes the connection transmits a usable-state notification message for the notification of the usable-state of the address, which is used when said mobile communication device establishes the connection with the other access router in said subnetwork under the management of the other access router, to said mobile communication device.
4 . The communication network management method according to claim 1 , comprising:
a step in which said access router with which said mobile communication device establishes the connection acquires address information on the other access router; and
a step in which said access router with which said mobile communication device establishes the connection generates the request message to be transmitted to the other access router, on the basis of the address information on the other access router.
5 . A communication network management method for a communication system including a plurality of access routers and a mobile communication device connectable to a subnetwork under management of each of the plurality of access routers, comprising:
a step in which said mobile communication device acquires address information on said plurality of access routers;
a step in which, when establishing a connection with one of said plurality of access routers, said mobile communication device transmits a message for confirming the uniqueness of an address, which is used in a subnetwork under the management of said access router with which said mobile communication device establishes the connection, to an arbitrary node in said subnetwork under the management of said access router with which said mobile communication device establishes the connection and, on the basis of the address information on said plurality of access routers, transmits, to the other access router, a request message for making a request for confirming the uniqueness of an address used when said mobile communication device establishes the connection with the other access router in said subnetwork under the management of the other access router; and
a step in which, upon receipt of the request message from said mobile communication device, the other access router confirms the uniqueness of the address used by said mobile communication device in said subnetwork under the management of the other access router.
6 . The communication network management method according to claim 5 , comprising:
a step of, when a result of the conformation of the uniqueness of the address, which is used by said mobile communication device, in the other access router shows that the address is unusable because of being in a duplicate state, transmitting, to said mobile communication device, an unusable-state notification message for notifying that the address is unusable.
7 . The communication network management method according to claim 6 , comprising:
a step of, when a result of the conformation of the uniqueness of the address, which is used by said mobile communication device, in the other access router shows the confirmation of the uniqueness of the address, transmitting, to said mobile communication device, a usable-state notification message for notifying that the address is usable.
8 . The communication network management method according to claim 2 , comprising:
a step of, when said mobile communication device does not receive the unusable-state notification message from said access router with which the mobile communication device establishes the connection, making a decision that the address, which is used when said mobile communication device establishes a connection with the other access router in said subnetwork under the management of the other access router, is usable so that the address decided as being usable is used without confirming the uniqueness of the address when said mobile communication device moves and establishes a connection with the other access router.
9 . The communication network management method according to claim 8 , comprising:
a step in which each of said plurality of access routers existing in a predetermined area transmits an area information message including the same area information corresponding to the same predetermined area periodically or in accordance with a request from said mobile communication device;
a step of acquiring and holding the area information message when said mobile communication device establishes a connection with each of said plurality of access routers; and
a step in which said mobile communication device makes a comparison between the area information acquired from said access router to be connected thereto after movement and the area information acquired from said access router connected thereto when a decision is made that the address to be used at the connection with the other access router is usable and, when the two area information agree with each other, a decision is made that the access router to be connected thereto after the movement is the other access router related to the address which was already decided as being usable.
10 . The communication network management method according to claim 1 , comprising:
a step in which each of said plurality of access routers transmits a prefix information message including prefix information on said subnetwork under the management of said access router periodically or in accordance with a request from said mobile communication device;
a step in which, at a connection with one of said plurality of access routers, the mobile communication device generates an address to be used in a subnetwork under the management of said access router, with which said mobile communication device establishes the connection, by making a combination of the prefix information and an interface ID of said mobile communication device; and
a step in which, when the interface ID of said mobile communication device is included in the request message, the other access router generates the address, which is used by the mobile communication device in said subnetwork under the management of the other access router and which is used for confirming the uniqueness, by making a combination of the prefix information on said subnetwork under the management thereof and the interface ID of said mobile communication device.
11 . An access router for use in a communication system including a plurality of access routers each managing a subnetwork with which a mobile communication device is connectable, comprising:
address confirmation message reception means for receiving, from said mobile communication device establishing a connection with a subnetwork under management of said access router, a message for confirming the uniqueness of an address to be used by said mobile communication device in said subnetwork;
address confirmation request means for, upon receipt of the address confirmation message from said mobile communication device, transmitting, to the other access router, a request message for making a request for confirming the uniqueness of the address used when said mobile communication device establishes a connection with the other access router in a subnetwork under management of the other access router;
address duplicate reception means for receiving a confirmation result indicative of the fact that the address detected by the other access router is unusable; and
unusable-state notification means for, upon receipt of the confirmation result indicative of the unusable state of the address from the other access router, notifying, to said mobile communication device, the unusable-state of the address used when said mobile communication device establishes a connection with the other access router in said subnetwork under the management of the other access router.
12 . The access router according to claim 11 , comprising:
address confirmation reception means for receiving a confirmation result, indicative of the fact that the address detected by the other access router is usable, from the other access router; and
usable-state notification means for, upon receipt of the confirmation result indicative of the usable-state of the address from the other access router, notifying, to said mobile communication device, the usable-state of the address to be used when said mobile communication device establishes a connection with the other access router in said subnetwork under the management of the other access router.
13 . The access router according to claim 11 , comprising:
address information holding means for holding address information on the other access router existing in a predetermined area;
request message generation means for generating the request message to the other access router on the basis of the address information on the other access router held in said address information holding means; and
area information transmission means for transmitting an area information message including the same area information as area information set in the other access router existing in the same predetermined area periodically or in accordance with a request from said mobile communication device.
14 . An access router for use in a communication system including a plurality of access routers each managing a subnetwork with which a mobile communication device is connectable, comprising:
address confirmation request reception means for receiving a request message transmitted from an access router, different from said access router, which has received a message transmitted from said mobile communication device establishing the different access router to make a request for confirming the uniqueness of an address to be used in the subnetwork under management, with the request message being for making a request for confirming the uniqueness of the address to be used by said mobile communication device in said subnetwork under the management thereof; and
address confirmation means for, upon receipt of the request message, confirming the uniqueness of the address to be used by said mobile communication device in said subnetwork under the management thereof.
15 . The access router according to claim 14 , comprising address duplicate notification means for, when a result of the confirmation on the uniqueness of the address to be used by said mobile communication device shows that the address is unusable because of being in a duplicate state, notifying the unusable-state of the address to the access router with which said mobile communication device establishes a connection.
16 . An access router for use in a communication system including a plurality of access routers each managing a subnetwork with which a mobile communication device is connectable, comprising:
address confirmation request reception means for receiving a request message from said mobile communication device, which establishes a connection with an access router different from said access router, for making a request to confirm the uniqueness of an address to be used by said mobile communication device in a subnetwork under management; and
address confirmation means for, upon receipt of the request message, confirming the uniqueness of the address to be used by said mobile communication device in the subnetwork under the management.
17 . The access router according to claim 16 , comprising unusable-state notification means for, when a result of the confirmation on the uniqueness of the address to be used by said mobile communication device shows a detection of the address being unusable because being in a duplicate state, notifying the unusable-state of the address to said mobile communication device.
18 . The access router according to claim 14 , comprising address reservation means for, when a result of the confirmation on the uniqueness of the address to be used by said mobile communication device shows the confirmation of the uniqueness of the address, carrying out address reservation processing to inhibit the use of the address by a communication device other than said mobile communication device.
19 . The access router according to claim 14 , comprising area information transmission means for transmitting an area information message including area information set to be identical to area information set in said plurality of access routers existing in a predetermined area periodically or in accordance with a request from said mobile communication device.
20 . The access router according to claim 14 , comprising address generation means for, when the interface ID of said mobile communication device is included in the request message, generating the address to be used by said mobile communication device in the subnetwork under management, for the confirmation of the uniqueness by making a combination of prefix information on the subnetwork under the management and the interface ID of said mobile communication device.
21 . A mobile communication device, which is connectable to a subnetwork under management of each of a plurality of access routers, comprising:
message reception means for, at a connection with one of said plurality of access routers, receiving a message including information indicative of a predetermined function from said access router which is the object of connection;
address confirmation message transmission means for, at a connection with one of said plurality of access routers, transmitting a message for confirming the uniqueness of an address, which is used in a subnetwork under the management of said access router which is the object of connection, to an arbitrary node in said subnetwork under the management of said access router which is the object of connection;
timer means for measuring time upon receipt of the message including the information indicative of the predetermined function; and
address usage control means for, when the time measured by said timer means exceeds a predetermined time without receiving, from said access router which is the object of connection, a unusable-state notification message for a notification of an unusable-state of the address used when said mobile communication device establishes a connection with the other access router in a subnetwork under management of the other access router, executing control to use the address without confirming the uniqueness of the address at the connection with the subnetwork under the management of the other access router.
22 . A mobile communication device, which is connectable to a subnetwork under management of each of a plurality of access routers, comprising:
message reception means for, at a connection with one of said plurality of access routers, receiving a message including information indicative of a predetermined function from said access router which is the object of connection;
address information holding means for holding address information on said plurality of access routers;
message transmission means for, at a connection with one of said plurality of access routers, transmitting a message for confirming the uniqueness of an address, which is used in a subnetwork under the management of said access router which is the object of connection, to an arbitrary node in a subnetwork under the management of said access router which is the object of connection and for, on the basis of the address information on said plurality of access routers, transmitting, to the other access router, a request message for making a request for confirming the uniqueness of the address used when said mobile communication device establishes a connection with the other access router in a subnetwork under the management of the other access router;
timer means for measuring time upon receipt of the message including the information indicative of the predetermined function; and
address usage control means for, when the time measured by said timer means exceeds a predetermined time without receiving, from said access router which is the object of transmission of the request message, a unusable-state notification message for a notification of an unusable-state of the address used when said mobile communication device establishes a connection with the other access router in the subnetwork under the management of the other access router, executing control to use the address without confirming the uniqueness of the address at a connection with the subnetwork under the management of the other access router.
23 . The mobile communication device according to claim 21 , comprising:
a step for, at a connection with each of said plurality of access routers, acquiring an area information message including area information and holding the area information; and
area decision means for making a comparison between the area information acquired from said access router to be connected after movement and the area information acquired from said access router connected when a decision is made that the address used at the connection with the other access router is usable and for, when the two area information agree with each other, making a decision that said access router to be connected after the movement is the other access router related to the address which was already decided as being usable.
24 . The mobile communication device according to claim 21 , comprising address generation means for, at a connection with one of said plurality of access routers, generating an address to be used in the subnetwork under the management of said access router which is the object of connection by making a combination of the prefix information and the interface ID of the mobile communication device.
25 . The communication network management method according to claim 6 , comprising:
a step of, when said mobile communication device does not receive the unusable-state notification message from said access router with which the mobile communication device establishes the connection, making a decision that the address, which is used when said mobile communication device establishes a connection with the other access router in said subnetwork under the management of the other access router, is usable so that the address decided as being usable is used without confirming the uniqueness of the address when said mobile communication device moves and establishes a connection with the other access router.
26 . The communication network management method according to claim 5 , comprising:
a step in which each of said plurality of access routers transmits a prefix information message including prefix information on said subnetwork under the management of said access router periodically or in accordance with a request from said mobile communication device;
a step in which, at a connection with one of said plurality of access routers, the mobile communication device generates an address to be used in a subnetwork under the management of said access router, with which said mobile communication device establishes the connection, by making a combination of the prefix information and an interface ID of said mobile communication device; and
a step in which, when the interface ID of said mobile communication device is included in the request message, the other access router generates the address, which is used by the mobile communication device in said subnetwork under the management of the other access router and which is used for confirming the uniqueness, by making a combination of the prefix information on said subnetwork under the management thereof and the interface ID of said mobile communication device.
27 . The access router according to claim 16 , comprising address reservation means for, when a result of the confirmation on the uniqueness of the address to be used by said mobile communication device shows the confirmation of the uniqueness of the address, carrying out address reservation processing to inhibit the use of the address by a communication device other than said mobile communication device.
28 . The access router according to claim 16 , comprising area information transmission means for transmitting an area information message including area information set to be identical to area information set in said plurality of access routers existing in a predetermined area periodically or in accordance with a request from said mobile communication device.
29 . The access router according to claim 16 , comprising address generation means for, when the interface ID of said mobile communication device is included in the request message, generating the address to be used by said mobile communication device in the subnetwork under management, for the confirmation of the uniqueness by making a combination of prefix information on the subnetwork under the management and the interface ID of said mobile communication device.
30 . The mobile communication device according to claim 22 , comprising:
a step for, at a connection with each of said plurality of access routers, acquiring an area information message including area information and holding the area information; and
area decision means for making a comparison between the area information acquired from said access router to be connected after movement and the area information acquired from said access router connected when a decision is made that the address used at the connection with the other access router is usable and for, when the two area information agree with each other, making a decision that said access router to be connected after the movement is the other access router related to the address which was already decided as being usable.
31 . The mobile communication device according to claim 22 , comprising address generation means for, at a connection with one of said plurality of access routers, generating an address to be used in the subnetwork under the management of said access router which is the object of connection by making a combination of the prefix information and the interface ID of the mobile communication device.