JP3536919B2 - Communication network control system and method, router - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication network control system and method for performing communication control in a mobile communication hierarchical network.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a configuration of a conventional mobile communication network. This mobile communication network is generally used for a cellular phone network, a position management system of an automobile on an expressway, and the like, and is a network that performs communication by packet communication using a TCP / IP protocol or the like. .

As shown in FIG. 6, this mobile communication network comprises an upper network 1 and a plurality of routers R _n.
(N = 1 to 7), fixed base stations BS _{1 to} BS ₈ and a mobile unit MH. The upper network 1 may be a wide area network, for example, the Internet. Each router R _n is for branching connecting upper network system 1 and the respective base stations BS ₁ to BS _8. Each router R _n are hierarchically connected. The router R _{1 in the} uppermost layer is connected to the upper network 1.
The lower layer of the router R ₁ has the router R ₂ and R _3, respectively is connected to the router R _1, router R ₁ is a subordinate them. Routers R ₄ and R ₅ and routers R ₆ and R ₇ are connected to lower layers of the routers R ₂ and R ₃ , respectively, and the routers R ₂ and R ₃ control them. Also, the router R ₄ is the base station BS _1, BS _2, the base station B to the router R ₅
S ₃ and BS ₄ , base stations BS ₅ and BS ₆ at router R ₆ ,
The base station BS _7, BS ₈ to the router R ₇ are connected respectively, each router R ₄ to R ₇ is a subordinate them. Mobile MH is wirelessly connected by radio to one of the base stations of the base station BS ₁ to BS _7, establishes a communication path to the upper network system 1 as shown below communication partner (not shown) Communication with the

[0004] The location registration message transmitted from the mobile MH is transmitted to the base station BS _n (). Each router R _n
Updates the routing information based on the message, and forwards the message to an upper-layer router (,,). The route information, when receiving a packet of a mobile MH addressed, a path information for indicating the destination of the packet, the routing information is registered in the routing table included in the router R _n. Therefore, when the position registration message reaches the router R ₁ in the uppermost, the communication path to the mobile MH in the network is established. For example, in FIG.
The base station BS ₂ - routers R ₄ - Router R ₂ - communication path of the router R ₁ is established. In this case, as shown in FIG. 7, the packet mobile MH destined transmitted from the host network system 1, the router R ₁ - Router R ₂ - routers R ₄ -
It is transmitted in the order of base station BS ₂ -mobile MH.

In such a network, if a router (eg, router R2 in FIG. 7) in the middle of a communication path between the upper network 1 and the mobile unit MH stops due to a failure or the like, the communication path is disconnected. I will. In this network, since there is no route other than the communication route through the router, the cause of the stop is removed by repairing the stopped router, etc., and the network is restored by restarting the router, and the mobile based on the location registration message transmitted from the MH, to the router R ₂ and the like as a communication path between the mobile MH an upper network system 1 again, the communication by updating the routing information, such as a router R ₂ Route must be restored. In other words, in this network, when the communication path is interrupted, the network is restored, and the communication between the upper network 1 and the mobile MH is continued until the mobile unit MH transmits a location registration message again to open the communication path. Communication cannot be restored.

In FIGS. 6 and 7, the moving object is a moving object MH.
, But in a real network,
It is common to communicate with a plurality of mobiles.
In this case, when the network spreads, a location registration message is transmitted for each mobile unit. Then, this network so tree-like network that branches from the router R ₁ to a plurality of base stations, The more routers upper layer, the greater the number of location registration message sent. Therefore, when a location registration message is transmitted from a plurality of mobile units, there is a problem that the load on the router in the upper layer increases.

[0007]

As described above, in a conventional hierarchical network in mobile communication, if a router or line in the middle of a communication path stops, the communication path is disconnected, and after the network is restored, the communication path is disconnected. Until the location registration message is transmitted again from the mobile unit and a communication path is established, communication between the upper network and the mobile unit cannot be restored.

In addition, as described above, if communication between the upper network and the mobile unit cannot be restored until the location registration message is transmitted again from the mobile unit and a communication path is established, a plurality of mobile units are required. Then, the higher the layer in the network, the greater the number of location registration messages transmitted after the restoration of the network, resulting in a problem that the load on the router in the upper layer increases.

It is an object of the present invention to provide a communication network control system and a communication network control method that can continue communication even if a router or line on the communication path stops.

[0010]

In order to solve the above-mentioned problems, in a communication network control system according to the present invention, a plurality of radio base stations are connected to any one of the radio base stations by radio to perform communication. A plurality of routers for routing a communication path between a mobile unit and a higher-level network and each of the radio base stations are hierarchically connected, a router at the highest level is connected to the higher-level network, and In a communication network control system including a hierarchical network in which a router is connected to each of the radio base stations, in each hierarchical layer of the hierarchical network, a connection destination of an upper layer and a connection destination of a lower layer are the same. , a plurality of the same route router having the same path information are provided, each of the same path Le
Data router selects any one of the same-router routers in the lower layer as a communication route router on a communication route between the higher-level network and the mobile unit;
When it is determined that the router has become unable to communicate, another router among the routers of the same route is selected as the router of the communication route.

In the communication network control system according to the present invention, when a router set as a communication path router out of the same path routers becomes unable to communicate, the communication path router is automatically changed to another one of the same path routers. Switch to. In the communication network control system of the present invention, since the same route router has the same route information, even if the communication route router is switched to another router, the packet can be transmitted to the destination before switching. Therefore, in the communication network control system of the present invention, communication can be continued even if a router or line on the communication path stops.

[0012]

Next, a communication network control system according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the communication network control system according to the present embodiment. As shown in FIG. 1, the communication network control system according to the present embodiment includes an upper network 1 and a router R _n p (n = 1 to
7), and a router _{R n s (n = 1~7)} , and a plurality of radio base stations BS ₁ to BS _8, and a moving body MH.

The routers R ₁ p and R ₁ s are the highest-layer routers connected to the upper network 1. Router R ₁
p and R ₁ s are lower layer routers R ₂ p, R ₂ s and router R ₃
It is also connected to p and R ₃ s. That is, router R
₁ p, R ₁ s are each a is the same as the connection destination of the connection destination and the lower layer of the upper layer, the same path router having the same path information. P of the router R ₁ p is a primary (primar
y, first), and s of the router R ₁ s means secondary (secondary). Router R ₂ p, R ₂ s
The routers R ₇ p and R ₇ s are also the same route routers.

The routers R ₂ p and R ₂ s are routers R in the lower layer.
₄ p, R ₄ s and routers R ₅ p, R ₅ s, and routers R ₃ p, R ₃ s are lower-layer routers R ₆ p, R ₆ s and routers R ₇ p, R ₇ s And connected to. Router R ₄ p, R
₄ s, the router _{R 5 p, R 5 s,} R 6 p, R 6 s, the router R
₇ p, R ₇ s is the lowest layer router, and router R ₄ p,
R ₄ s is connected to base stations BS ₁ and BS ₂ , routers R ₅ p and R ₅ s are connected to base stations BS ₃ and BS ₄ , and routers R ₆ p and R ₆ s , Base stations BS ₅ and BS ₆ , and routers R ₇ p and R ₇ s are connected to base stations BS ₇ and B ₇
It is connected to the S _8. The mobile unit MH is wirelessly connected to the base station B.
Connect to any one of S _{1 to} BS ₈ base stations.

As described above, in the communication network control system of the present embodiment, the same route routers R _n p and R _n
Of s, the router R _n p, if selected as the communication path router on the communication path between the host network system 1 and the mobile MH, routers R _n p becomes impossible communication, a router R _n s is selected as the communication route router.

In FIG. 1, the number of same-router routers is two.
Although the number of router layers is three and the number of base stations is eight, the mobile communication network control system of the present invention is not limited to this. The number of layers, the number of connections, or the number of base stations
Any number may be used.

Next, the operation of the communication network control system of this embodiment, that is, the communication network control method of this embodiment will be described. 2 to 5 are block diagrams illustrating the operation of the communication network control system according to the present embodiment. FIG. 2 shows routers R ₁ p and R ₁ s-router R ₂
p, R ₂ s-the state of communication between the routers R ₄ p and R ₄ s is shown. As shown in FIG. 2, the routers R ₁ p, R ₁ s
The router R ₂ p, R ₂ s in the lower layer, respectively router R ₁
A message is periodically transmitted to p and R ₁ s to notify that they have not stopped functioning.
Similarly, routers R ₄ p and R ₄ s are respectively router R
Sending periodic messages to ₂ p, R ₂ s. The routers R ₁ p and R ₁ s in the uppermost layer periodically transmit messages to the routers R ₂ p and R ₂ s in the lower layer. Similarly, routers R ₂ p and R ₂ s similarly transmit messages to routers R ₄ p and R ₄ s at regular intervals. This message includes a flag called a primary flag. The router that has received the message with the primary flag turned on from the router in the upper layer determines that it has been selected as the communication path router, and operates as a communication path router.

In FIG. 2, the router R ₁ p is set as a communication route router of the highest layer. The router R ₁ p periodically sends a message with the primary flag turned on to the lower layer router R ₂ p, and periodically sends a message with the primary flag turned off to the router R ₂ s. Send. The router R ₂ p set as the communication path router periodically sends the message with the primary flag turned on to the lower layer router R ₄ p and sends the message with the primary flag turned off to the router R ₂ s. Send regularly. Router R that is not a communication route router
₁ s periodically sends a message with the primary flag turned off to both routers R ₂ p and R ₂ s, and router R ₂ s, which is not a communication route router, routers R ₄ p and R ₂ p
_{For 4} s, periodically send a message with the primary flag turned off.

As described above, as shown in FIG. 2, in the communication network control system according to the present embodiment, routers in each layer periodically transmit and receive messages, and use the primary flag included in the messages to for example, the to select the communication route router as a router R ₁ p-router R ₂ p-router R ₄ p path is performed.

Next, as shown in FIG. 3, when the mobile unit MH connects to the base station, a location registration message is notified from the lower layer router to the upper layer router, so that the entire network is connected to the mobile unit MH. A communication path is established. At this time, the lower layer router notifies the same location registration message to all connected upper layer same-router routers.

[0022] FIG. 3, the mobile MH is shown a state when connected to the base station BS _2. When the moving body MH is connected to the base station BS _2, mobile MH transmits a position registration message to the base station BS ₂ (). The base station BS ₂ is the same route router R ₄ p, transfers the location registration message to both the R ₄ s (as'). The routers R ₄ p and R ₄ s update their own route information. Next, router R ₄ p forwards the location registration message to both router R ₂ p and router R ₂ s (and '). Since the router R ₄ s has not received the message with the primary flag turned on from the router in the upper layer and has not been selected as the communication route router, it does not transfer the location registration message. Next, the routers R ₂ p and R ₂ s update the route information. Router R ₂ p forwards the location registration message to both routers R ₁ p and R ₁ s (and '). The router R ₂ s which is not the communication route router does not transfer the location registration message. The routers R ₁ p and R ₁ s update the route information. As described above, the communication path of the router R ₁ p-router R ₂ p-router R ₄ p-base station BS ₂ is established.

Next, as shown in FIG. 4, when the router R ₂ p stops due to a fault, the router R ₂ p sends the upper-layer routers R ₁ p and R ₁ s and the lower-layer routers R ₄ p and R _4. s will not be sent.

As shown in FIG. 5, the router R ₁ p of the upper layer of the router R ₂ p is a message from the router R ₂ p is a predetermined time, the router R ₂ p is stopped if it is not transmitted determination and, so as to periodically notify message for the primary flags with respect to the router R ₂ s, selects the router R ₂ s as the communication path router. Then, the router R ₂ s operates as a communication route router.
The route information to the mobile unit MH on the router R ₂ s is the router R ₂ p
Therefore, the router R ₂ s can maintain the communication between the upper network 1 and the mobile unit MH even if the router R ₂ s is switched as a communication route router.

As described above, in the communication network control system of the present embodiment, when a router designated as a communication path router out of the same path routers becomes unable to communicate, the communication path router is switched to another router. . In the communication network control system of the present embodiment, since the same route router has the same route information, even if the communication route router is switched to another router, the packet can be transmitted to the destination before switching. . Therefore, in the communication network control system of the present embodiment, communication can be continued even if a router or line in the middle of the communication path stops.

[0026]

As described above, according to the communication network control system of the present invention, when a router designated as a communication path router out of the same path router becomes unable to communicate, the communication path router is changed to another router. Switch. In the communication network control system of the present invention, since the same route router has the same route information, even if the communication route router is switched to another router, the packet can be transmitted to the destination before switching. Therefore, in the communication network control system of the present invention, communication can be continued even if a router or line on the communication path stops.

Further, since communication can be continued even if a router or line in the middle of a communication path is stopped, a location registration message is transmitted from a plurality of mobile units to an upper layer of the network after the network is restored, and The problem that the load on the router in the layer increases can also be solved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a communication network control system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a regular message exchange operation of the communication network control system according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a path information update operation of the communication network control system according to one embodiment of the present invention.

FIG. 4 is a block diagram showing an operation of the communication network control system according to the embodiment of the present invention when a communication route router fails.

FIG. 5 is a block diagram illustrating an operation of switching a communication path of the communication network control system according to the embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional mobile communication network.

FIG. 7 is a block diagram showing a configuration of a conventional mobile communication network.

[Explanation of symbols]

1 upper network system BS ₁ to BS ₈ base station _{R 1 ~R 7, R 1 p~R} 7 p, R 1 s~R 7 s router MH mobile

Claims (9)

(57) [Claims] 1. A plurality of wireless base stations, a mobile unit that wirelessly connects to any of the wireless base stations to perform communication, and routes a communication path between a higher-level network and each of the wireless base stations. Communication network control comprising a hierarchical network in which a plurality of routers are hierarchically connected, an uppermost router is connected to the upper network, and a lowermost router is connected to each of the radio base stations. In the system, in each layer of the hierarchical network, a plurality of same-route routers having the same upper-layer connection destination and lower-layer connection destination and having the same route information are provided, and each of the same-route routers is provided. but select, the one of the routers of the same route router lower layer, as the communication path router on the communication path between the mobile body and the upper network system , It determines that the router has become incommunicable
In this case, a different one of the same route routers is selected as the communication route router. 2. A router selected as the lower layer communication path router among the lower layer same path routers,
The upper layer communication path router periodically transmits a message to the upper layer communication path router, and the upper layer communication path router does not transmit a message for a predetermined time from the router selected as the lower layer communication path router. communication network control system according to claim 1, wherein the router selects another same route router as a communication path router of the lower layer is determined that a communication failure when. 3. The same-router router updates the route information based on a location registration message of the mobile unit transmitted from a lower layer, and is selected as a communication-router router among the respective same-router routers. 3. The communication network control system according to claim 1, wherein said router transfers the location registration message to all connected upper-layer routers having the same route. 4. A plurality of wireless base stations, a mobile unit that wirelessly connects to any of the wireless base stations to perform communication, and routes a communication path between a higher-level network and each of the wireless base stations. Communication of a system comprising a hierarchical network in which a plurality of routers are hierarchically connected, a highest-layer router is connected to the higher-level network, and a lowest-layer router is connected to each of the wireless base stations. a network control method, each layer of the hierarchical network, the same connection destination of the connection destination and the lower layer of the upper layer is in advance provided with a plurality of identical path router having the same path information, each same route router, the one of the routers of the same route router lower layer, and a communication path router on a communication path between the mobile body and the upper network system Select Te, it determines that the router has become incommunicable
When the communication network control method for selecting another router of said respective same route router as the communication path router. 5. The router selected as the lower layer communication path router among the lower layer same path routers,
The upper layer communication path router periodically transmits a message to the upper layer communication path router, and the upper layer communication path router does not transmit a message for a predetermined time from the router selected as the lower layer communication path router. 5. The communication network control method according to claim 4 , wherein in such a case, it is determined that the router has become unable to communicate, and another identical path router is selected as the lower layer communication path router. 6. The same-router router updates the route information based on a location registration message of the mobile unit transmitted from a lower layer.
6. The communication network control method according to claim 4 , wherein the router selected as the communication route router transfers the location registration message to all connected upper-layer same-route routers. 7. A plurality of hierarchically connected communication routes between a plurality of radio base stations for wirelessly connecting to a mobile unit and communicating with a higher-level network and having the same route information. One of the same route routers, wherein one of the lower route same route routers is used as a communication route router on a communication route between the upper network and the mobile unit. A router that selects a different one of the same-router routers as the communication-router when it is determined that the router selected as the communication-router router has become unable to communicate. 8. When a communication path router is selected, a message is periodically transmitted to an upper-layer router, and a lower-layer communication path router that periodically transmits a message is selected. 8. The router according to claim 7 , wherein when the message is not transmitted from the router for a predetermined time, the router is determined to have become unable to communicate. 9. The route information is updated based on a position registration message of the mobile unit transmitted from a lower layer, and a router selected as a communication route router among the same route routers is connected. The router according to claim 7 or 8 , wherein the location registration message is transferred to all the same-layer routers in the upper layer.