JP2008193318A - Ad hoc network system and gateway selection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dynamically select a mobile router for providing a gateway function in an ad hoc network. <P>SOLUTION: A mobile router 4 periodically advertises gateway costs while providing a gateway function (S85). The other mobile router 4' compares the gateway costs of the mobile router 4 with its own (S87), stands as a candidate when it judges that its own is more appropriate, and advertises its own gateway costs (S88). The mobile router 4 compares its own gateway costs with those of the mobile router which has stood as a candidate and judges that its own is not better (S89), it stops providing the gateway function and selects as a gateway the mobile router 4' which has stood as a candidate (S90). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ad hoc network system and a gateway selection method.

  Along with the development of network infrastructure, technologies for providing a connection environment to the Internet and the like have been developed even in high-speed moving bodies such as trains and airplanes, and mobile IP (Internet Protocol) networks configured in high-speed moving bodies and A network mobility technique for realizing seamless IP packet transfer with an external fixed IP network is discussed in the IETF Network Mobility (NEMO) Working Group (for example, see Non-Patent Document 1). The mobile network is connected to a fixed network via a default gateway called a mobile router, and the mobile router performs a handover process or the like associated with a change in the fixed IP network to which the mobile network is connected.

  On the other hand, the terminal node itself has an IP packet relay function, and a plurality of nodes transfer IP packets to each other, so even if the network infrastructure such as a wireless base station cannot be used or does not exist, The ad hoc network technology that enables communication in the Internet is discussed in IETF Mobile Ad-hoc Networks (MANET) Working Group. Among them, a technique for connecting an ad hoc network to an external network is also discussed. For example, as shown in FIG. 18, a plurality of nodes constitute an ad hoc network, and each node in the ad hoc network is connected to the Internet. A method of connecting to an external network such as the Internet through a functioning Internet GW is shown (for example, see Non-Patent Document 2).

  However, an apparatus constituting an ad hoc network is an IPv6 node or a Mobile IPv6 node, which is not a mobile router that accommodates a mobile network, and in the case where there are a plurality of nodes that can serve as Internet gateways in the ad hoc network. The method of selecting a node that operates as a gateway is not subject to this draft.

  Further, in an ad hoc network, a method of disseminating information related to the Internet gateway to each node constituting the ad hoc network is mentioned in the discussion regarding the path control of the ad hoc network. For example, in an ad hoc network, a protocol called OLSR for determining routes in advance defines an MPR set for the purpose of limiting “forwarding nodes” in order to make flooding into the ad hoc network efficient. (For example, see Non-Patent Document 3.) The trigger for recalculating the MPR set (trigger for recalculating route information) includes periodic message exchange (Hello, TC) and external trigger, and each node constituting the ad hoc network forwards the packet to another node. “Willingness” indicating the degree of intention to do so is advertised to an adjacent node, and this value is used as a selection condition for the MPR node. Regarding gateways to external networks, Appendix F. 3 is generally described. An example is described in which basic routing with the outside can be supported using a TC message, and a gateway advertises a static route to an external network. However, this document does not describe a method for selecting a gateway in an ad hoc network.

  Further, “DYMO”, which is one of ad hoc network routing protocols, has been proposed (see, for example, Non-Patent Document 4). In this document, “Route.IsGateway” is defined in the data structure, and there is a gateway to the external network in the ad hoc network, and it is conscious that the packet is a transmission packet to the external network. However, it does not mention how to select a node to be a gateway.

  Also, in an ad hoc network where there are multiple gateway nodes with an external network, each node in the ad hoc network uses a message that advertises its existence to the ad hoc network at regular intervals, and It has been proposed to calculate communication quality up to a gateway node and determine which node of a plurality of gateways is used (see, for example, Patent Document 1). In this document, the communication quality is estimated from the reception status of the advertisement message in the upper layer without using the radio quality information in the radio link layer. However, this document assumes that a plurality of gateway nodes exist in a fixed manner, and does not disclose a method for selecting a unique gateway from a plurality of gateway nodes.

JP 2006-5768 A IETF RFC3963 “Network Mobility (NEMO) Basic Support Protocol”, Jan 2005 IETF Draft “Global connectivity for IPv6 Mobile Ad Hoc Networks”, Draft-Wakikawa-manet-globalv6-03. txt, Oct 2003. IETF Draft “The Optimized Link-State Routing Protocol version 2”, draft-ietf-manet-olsrv2-01. txt: March 6, 2006 IETF Draft “Dynamic MANET On-demand (DYMO) Routing”, draft-ietf-manet-dymo-04. txt: March 5, 2006

  A plurality of mobile routers (MRs) that accommodate mobile networks and manage communication associated with movement using mobile IP technology constitute an ad hoc network, relay communication within the ad hoc network, and connect to external networks such as the Internet Is considered as a case where another mobile router (MR) in a communicable state connected to an external network such as the Internet is used as a gateway.

  As shown in FIG. 1, a plurality of mobile routers (MR) 4, 4 ′, 4 ″ accommodating a mobile network are connected to each other via a wireless link, and one mobile router 4 among these mobile routers is a gateway. (IGW), which is connected to an access router (access router (AR)) 14 via a wireless link, and enables communication with an external network via a home agent (HA) 16. The provided mobile router 4 (MR1) receives the router advertisement 17 transmitted from the access router (AR) 14, determines its own IPv6 address (care-of address), and processes as a mobile IP (home agent: HA registration, encapsulation / decapsulation, etc.) Ad hoc network The other mobile routers (MR2, MR3) 4 ′, 4 ″ in 00 receive the IGW advertisement 18 from the mobile router 4 (MR1) which is the gateway (IGW), and which mobile router currently provides the IGW function. And the packet outside the ad hoc network 100 is transferred to the mobile router 4 (MR1) which is the gateway (IGW), and the gateway (IGW) performs the mobile IP encapsulation processing to access router (AR) 14 for transfer. Packet transfer in the ad hoc network 100 is performed by normal IPv6 packet transfer.

At this time, the entry / exit of the MR constituting the ad hoc network into the ad hoc network may be a dynamic case or a static case, but has the following problems.
(1) Even if the MR constituting the ad hoc network is a fixed ad hoc network, an MR suitable for providing an IGW function with a radio link with an access router (AR) cannot be fixed. It may be better to provide the IGW function.
(2) When the MR configuring the ad hoc network is a dynamic ad hoc network, when the MR providing the IGW function leaves the ad hoc network, it is necessary to newly select the MR providing the IGW function .
From the above (1) and (2), each MR constituting the ad hoc network can receive router advertisements received from the access router (AR), IGW advertisements received from other MRs, route information in the ad hoc network, etc. From the information, it is necessary to dynamically determine which MR in the ad hoc network provides the IGW function and change the IGW function to an appropriate MR.

  The present invention has been made to solve such a problem, and an ad hoc network system and a gateway capable of dynamically selecting an MR that provides an Internet gateway function and changing the MR within the ad hoc network. The purpose is to obtain a selection method.

  In the present invention, any one of a plurality of mobile routers accommodating a mobile network establishes a radio link with each other to form an ad hoc network, performs communication within the ad hoc network, and can be connected to an access router. An ad hoc network system in which a mobile router operates as a gateway between an ad hoc network and an external network, and the mobile router is mounted on a mobile unit and establishes a wireless link with an access router connected to the external network, Performs packet relay between the mobile network that accommodates the terminals inside the mobile unit and the external network, and periodically checks whether or not a radio link can be established with multiple nearby access routers, and can use it by referring to the test results Cost information for a simple radio link And selecting an appropriate access router based on the cost information of the wireless link, wherein the access router is connected to the external network and relays packets between the mobile router and the external network. The cost information of the radio link includes the current value of the transmission rate and error rate in the radio link layer, the current position information, the moving direction information, the moving speed information, and the moving schedule of the mobile unit on which the mobile router is mounted. Predicted position after a certain time calculated from the route information, position information of the wireless base station used by the access router for wireless link connection with the mobile router, and an antenna installed on the mobile unit providing the wireless link Provided by the wireless link using the performance value of the antenna and the performance value of the antenna installed in the base station providing the wireless link Is calculated from the available communication time and the average transmission rate, and at least one of the mobile router and the access router uses the cost information of the wireless link, and each mobile router is a gateway in the ad hoc network. The ad hoc network system is characterized in that a gateway cost serving as a priority index for operating as a gateway is calculated and a mobile router operating as a gateway in the ad hoc network is selected using the gateway cost.

    In the present invention, any one of a plurality of mobile routers accommodating a mobile network establishes a radio link with each other to form an ad hoc network, performs communication within the ad hoc network, and can be connected to an access router. An ad hoc network system in which a mobile router operates as a gateway between an ad hoc network and an external network, and the mobile router is mounted on a mobile unit and establishes a wireless link with an access router connected to the external network, Performs packet relay between the mobile network that accommodates the terminals inside the mobile unit and the external network, and periodically checks whether or not a radio link can be established with multiple nearby access routers, and can use it by referring to the test results Cost information for a simple radio link And selecting an appropriate access router based on the cost information of the wireless link, wherein the access router is connected to the external network and relays packets between the mobile router and the external network. The cost information of the radio link includes the current value of the transmission rate and error rate in the radio link layer, the current position information, the moving direction information, the moving speed information, and the moving schedule of the mobile unit on which the mobile router is mounted. Predicted position after a certain time calculated from the route information, position information of the wireless base station used by the access router for wireless link connection with the mobile router, and an antenna installed on the mobile unit providing the wireless link Provided by the wireless link using the performance value of the antenna and the performance value of the antenna installed in the base station providing the wireless link Is calculated from the available communication time and the average transmission rate, and at least one of the mobile router and the access router uses the cost information of the wireless link, and each mobile router is a gateway in the ad hoc network. As an ad hoc network system, which calculates the gateway cost that serves as a priority index to operate as a gateway and selects a mobile router that operates as a gateway in the ad hoc network using the gateway cost, an Internet gateway function is provided. The MR to be selected can be selected dynamically and can be changed within the ad hoc network.

Embodiment 1 FIG.
FIG. 4 shows a configuration diagram of an apparatus for providing a moving network to a high-speed moving body such as a train or an aircraft in the first embodiment of the present invention. As shown in FIG. 4, the high-speed moving body 1 is provided with at least one or more antennas 2. The high-speed moving body 1 is connected to the wireless access control device 3 connected to the antenna 2, the mobile router 4 connected to the wireless access control device 3, and the mobile router 4 via the mobile network 5. One or more mobile terminals 6 are also provided.

  As shown in FIG. 1, the mobile routers 4, 4 ′, 4 ″ are mounted on the high-speed moving body 1 and perform packet relay between a mobile network that accommodates terminals inside the high-speed moving body 1 and an external network. The access router 14 is connected to an external network and relays packets between the mobile routers 4, 4 ′, 4 ″ that accommodate the mobile network and the external network. The mobile routers 4, 4 ′, 4 ″ and the access router 14 establish a wireless link using one of the mobile routers as a gateway. Thereby, communication between the mobile network and the external network is performed. .

  The mobile routers 4, 4 ′, 4 ″ periodically check whether or not a wireless link can be established with a plurality of nearest access routers 14, and refer to the inspection result to obtain cost information of usable wireless links. Calculate an appropriate access router based on the cost information of the radio link.

  Further, a plurality of mobile routers 4, 4 ′, 4 ″ establish radio links with each other to form an ad hoc network and perform communication within the ad hoc network. Any mobile router that can connect to the network operates as a gateway between the ad hoc network and the external network.

  The operation will be described. As shown in FIG. 4, a mobile router 4 that provides a network mobility function is mounted on a high-speed moving body 1 such as a train or an aircraft, and a mobile network 5 laid inside the high-speed moving body 1 has a plurality of mobile terminals. 6 and the mobile router 4 are connected, and the mobile router 4 provides a connection environment to the external network for the mobile terminal 6 connected via the mobile network 5. The mobile router 4 is connected to a wireless access control device 3 for establishing a wireless link used for communication with an external network. The wireless access control device 3 is connected to at least one antenna 2; The radio access control device 3 establishes a radio link with a radio access control device (not shown) mounted on another mobile body and provides the radio link in the ad hoc network 100.

  FIG. 5 shows the configuration of the base station according to the first exemplary embodiment. As shown in FIG. 5, the base station 10 is provided with an antenna 12. In the base station 10, a radio access control device 13 connected to the antenna 12 and an access router 14 connected to the radio access control device 13 are provided. The access router 14 is connected to the home agent 16 via the Internet / fixed network 15.

  The wireless access control device 3 mounted on the high-speed moving body 1 is provided in a base station 10 that is fixedly installed on the ground as shown in FIG. 5, and provides an access router 14 that provides a connection function with an external network. When the mobile router 4 operates as a gateway by establishing a wireless link with the wireless access control device 13 connected to the network, the ad hoc network 100 can be connected to an external network.

  FIG. 6 shows functional configurations of the wireless access control device 3 and the mobile router 4 mounted on the high-speed moving body 1 in the first embodiment. As shown in FIG. 3, in the radio access control device 3, an antenna control unit 31, a receiver 32, a radio link quality determination processing unit 33, a transmitter 34, a mobile body position information processing unit 35, A mobile body movement information processing unit 36 is provided. In the mobile router 4, a radio link cost determination processing unit 41, a gateway determination processing unit 42, an ad hoc network route information processing unit 43, and an IGW advertisement processing unit 44 are provided.

  At this time, the radio access control device 3 uses one or more antennas 2 and determines whether or not a radio link can be established with another high-speed mobile unit or the radio access control device of the base station 10 in advance. The inspection is always performed periodically, and if the wireless link can be established, the wireless link is established. At this time, the antenna control unit 31 of the wireless access control device 3 mounted on the high-speed moving body 1 determines its own position, moving speed / direction, and planned moving path from the moving body position information processing unit 35 and the moving body movement information processing unit. 36, the antenna 2 is controlled, and an attempt is made to establish a radio link with another high-speed moving body or the base station 10. Further, the radio link quality determination processing unit 33 of the radio access control device 3 mounted on the high-speed moving body 1 uses radio link characteristics such as radio wave reception intensity, signal-to-noise ratio, transmission rate, and transmission error rate in an established radio link. The parameters related to quality are measured, and those parameters are provided to the mobile router 4.

  The radio link cost determination processing unit 41 of the mobile router 4 uses the current transmission rate and transmission error rate in the radio link obtained from the radio access control device 3 as a basis, the position of the connected mobile router, its own current position and moving direction. And the estimated speed after a certain period of time from each information of the moving speed and its own planned route, and information between the connected mobile routers from information such as parameters (beam direction controllable range, gain) regarding the performance of the antenna 2 An ad hoc network is configured when the transmission rate and the communicable time are predicted and the required radio link quality and communicable time can be expected.

  Furthermore, the radio link cost determination processing unit 41 of the mobile router 4 uses the current transmission rate and transmission error rate in the radio link obtained from the radio access control device 3 as a basis, the location of the connection destination base station, its current location, A predicted position after a predetermined time is determined from each information of the moving direction and moving speed, and the planned moving path of the mobile station, and the base station 10 The transmission rate and communication possible time with the mobile router 4 are predicted, and the IGW cost is calculated.

  In the gateway determination processing unit 42 of the mobile router 4, the IGW cost calculated by the radio link cost determination processing unit 41 and the IGW cost stored in the IGW advertisement received from the mobile router of another high-speed mobile unit in the ad hoc network are calculated. In comparison, the number of hops (the number of routes between nodes) from the mobile device of the ad hoc network to the mobile router of the ad hoc network from the route information with other mobile routers obtained from the ad hoc network route information processing unit 43 is minimized In consideration of this, it is determined whether or not it should operate as a gateway.

As described above, in this embodiment, a plurality of mobile routers that accommodate mobile networks establish radio links with each other to form an ad hoc network, perform communication within the ad hoc network, and communicate with the access router. An ad hoc network system in which any mobile router that can be connected operates as a gateway between an ad hoc network and an external network. The mobile router is mounted on a mobile unit and connected to an access router connected to the external network. The wireless link is established by the mobile network and the packet is relayed between the mobile network that accommodates the terminal inside the mobile unit and the external network, and the availability of the wireless link with the plurality of nearest access routers is periodically checked. Can be used with reference to test results Calculating cost information of a line link, and selecting an appropriate access router based on the cost information of the radio link, the access router being connected to the external network, the mobile router and the external network The cost information of the radio link includes the current value of the transmission rate and error rate in the radio link layer, the current position information and the moving direction information of the mobile unit on which the mobile router is mounted. A predicted position after a certain time calculated from the moving speed information and the planned moving route information, the position information of the wireless base station that the access router uses for the wireless link connection with the mobile router, and the movement that provides the wireless link The performance value of the antenna installed on the body and the performance value of the antenna installed in the base station that provides the radio link Is calculated from the communicable time and the average transmission rate that can be provided by the wireless link, and at least one of the mobile router and the access router uses the cost information of the wireless link to The router calculates the gateway cost, which is a priority index for the router to operate as a gateway in the ad hoc network, and uses the gateway cost to select the mobile router that operates as the gateway in the ad hoc network. The mobile router (MR) to be provided can be dynamically selected and changed within the ad hoc network.
In addition, in the transitional state when the mobile router that provides the gateway function is changed, the mobile router that provides the gateway function after switching is identified by the mobile router that provides the gateway function before switching. By notifying the currently connected access router, packets arriving at the access router destined for the mobile router that provides the gateway function before switching from the external network are sent to the mobile router that provides the gateway function after switching. Forwards packets that arrive at the mobile router that provides the gateway function before switching to the mobile router that provides the gateway function after switching in order to forward and forward from the ad hoc network to the external network via the access router. like Since, it is possible to prevent packet discard due to the transfer path can not be resolved in the packet forwarding in a transient state when the mobile router which provides a gateway function is changed.

  It should be noted that at least one of the mobile router and the access router has a current value of transmission speed and error rate in a lower layer of the radio link, current position information, moving direction information, and moving speed information of a mobile unit on which the mobile router is mounted. Installed on a mobile unit that provides a wireless link and a predicted position calculated after a certain amount of time and the predicted route information, the position information of the wireless base station that the access router uses for wireless link connection with the mobile router, and The communication performance time and average transmission rate that the wireless link can provide using the performance value of the antenna and the performance value of the antenna installed in the base station that provides the wireless link, and connection with other mobile routers in the ad hoc network Using the number of hops and the current transmission rate and error rate at the radio link layer between mobile routers, Ruruta calculates the gateway cost indicative of priority to operate as a gateway within an ad hoc network may be selected mobile router acting as a gateway in the ad hoc network using the gateway costs.

Embodiment 2. FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 1 and a home agent (HA) 16 that performs mobile IP processing, when a new gateway (IGW) of the ad hoc network 100 is selected and the state shown in FIG. 2 is obtained. An example of the operation is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 7, descriptions of the wireless access control devices installed at various places are omitted.

  As shown in FIG. 7, when the access router (AR) 14 can communicate with only one mobile router (MR), the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW). (Steps S 1 and S 2), the mobile router (MR 2) 4 ′, which is another mobile router (MR) constituting the ad hoc network 100, then establishes a radio link with the access router (AR) 14 and establishes a gateway ( IGW) is detected (step S3), the IGW cost when the wireless link with the access router (AR) 14 is established is estimated (step S4), and the current gateway The access router (A) via the mobile router (MR1) 4 (current IGW) which is (IGW) ) 14 to send the IGW cost information notification (Step S5).

  When the access router (AR) 14 receives the IGW cost information notification from the mobile router (MR1) 4 which is the current gateway (IGW) (step S5), the access router (AR) 14 is notified by the mobile router (MR2) notified by the IGW cost information notification. When the estimated cost information and the cost information in the connection with the mobile router (MR1) which is the current gateway (IGW) are compared, and it is determined that the gateway (IGW) should be changed as a result, the access router (AR) ) A mobile router (MR2) 4 ′, which is another MR that can establish a radio link with the network 14 and constitute the same ad hoc network 100, is selected as a new gateway (IGW) (step S6), and the current IGW (MR1) 4 is selected. A notification of IGW selection is transmitted to the new IGW (MR2) 4 ′ via the route (step S7). GW (MR2) 4 'sends the IGW elected acknowledgment to the access router (AR) 14 via current IGW (MR1) 4 (step S8). The current IGW (MR1) 4 transfers the IGW selection confirmation notification to the access router (AR) 14 and then stops communication with the access router (AR) 14 (step S9), and the access arrives at the current IGW (MR1) 4 The packet addressed to the router (AR) 14 is transferred to the new IGW (MR2) 4 ′ (step S10). The new IGW (MR2) 4 ′ starts to establish a radio link with the access router (AR) 14 immediately after transmitting the IGW selection confirmation notification (step S11), and the radio link with the access router (AR) 14 is established. Until the packet is transferred after being established, the packet addressed to the access router (AR) 14 transferred from the current IGW (MR1) 4 is buffered (step S12).

  When the access router (AR) 14 receives the IGW selection confirmation notification from the new IGW (MR2) 4 ′ via the current IGW (MR1) 4, the access destination of the radio link is changed from the current IGW (MR1) 4 to the new IGW (MR2). Switch to 4 ′ and establish a radio link with the new IGW (MR2) 4 ′. Also, from the reception of the IGW selection confirmation notification from the new IGW (MR2) 4 ′ until the new IGW (MR2) 4 ′ completes the address update process in the mobile IP, the home agent (HA) 16 previously Since the mobile IP packet arrives at the mobile router (MR1) (old IGW) 4 that was the gateway (IGW) until this point, the destination is changed to the new IGW (MR2) 4 ′ and buffered ( Step S13) After establishing a radio link with the new IGW (MR2) 4 ′ (step S14), the buffered mobile IP packet is transferred to the new IGW (MR2) 4 ′ (step S15).

  In the new IGW (MR2) 4 ′, after the radio link with the access router (AR) 14 is established, the buffered packet addressed to the access router (AR) 14 is transmitted (step S16), and in the ad hoc network 100 An IGW advertisement is transmitted to the mobile router (MR), and the gateway (IGW) is advertised to the mobile router (MR2) 4 ′.

  When the first IGW advertisement is received from the new IGW (MR2) 4 ′, the old IGW (MR1) 4 receives a new packet addressed to the access router (AR) 14 that has been transferred as a gateway (IGW) after a certain period of time. Transfer to the IGW (MR2) is stopped (step S18).

  As described above, in the present embodiment, a mobile router that constitutes an ad hoc network and a mobile router that is not itself a gateway detects that a wireless link used for connection with an access router can be established, Estimate the gateway cost when assuming that the gateway function is provided to other mobile routers, report the gateway cost as a result of the estimation to the access router to which the mobile router that is the current gateway is connected. It is appropriate to provide the gateway function in the ad hoc network by comparing the gateway cost reported from the mobile router that constitutes the ad hoc network with the gateway cost of the mobile router that provides the current gateway function. Select the mobile router to be the successor, instruct the mobile router selected as the successor to start providing the ad hoc network gateway function, and the mobile router that provides the current gateway function provides the gateway function Since one mobile router in the ad hoc network is selected as a gateway to the external network, the mobile router (MR) that provides this Internet gateway function is dynamically selected. In the ad hoc network, the packet can be changed, and even when the MR that provides the IGW function is changed, the packet can be prevented from being discarded in the transient state.

  In addition, in the transitional state when the mobile router that provides the gateway function is changed, the mobile router that provides the gateway function after switching is identified by the mobile router that provides the gateway function before switching. By notifying the currently connected access router, packets arriving at the access router destined for the mobile router that provides the gateway function before switching from the external network are sent to the mobile router that provides the gateway function after switching. Forwards packets that arrive at the mobile router that provides the gateway function before switching to the mobile router that provides the gateway function after switching in order to forward and forward from the ad hoc network to the external network via the access router. like Since, it is possible to prevent packet discard due to the transfer path can not be resolved in the packet forwarding in a transient state when the mobile router which provides a gateway function is changed.

Embodiment 3 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, the gateway (IGW) of the ad hoc network 100 is newly selected in the system shown in FIG. An example of the operation when the state shown in FIG. 2 is reached is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 8, descriptions of the wireless access control devices installed at various places are omitted.

  When the access router (AR) 14 can communicate with a plurality of MRs, the mobile router (MR1) 4 in the ad hoc network 100 operates as a gateway (IGW) (steps S11 and S12), and then the ad hoc network 100 When the mobile router (MR2) 4 ′, which is another MR constituting the network, detects that the mobile router (MR2) 4 ′ has established a wireless link with the access router (AR) 14 and can become a gateway (IGW), A radio link with the access router (AR) 14 is established (step S13), and an IGW cost is estimated (step S14), and an IGW cost information notification is transmitted to the access router (AR) 14 using this radio link ( Step S15).

  When the access router (AR) 14 receives the IGW cost information notification from the mobile router (MR2) 4 ′ (step S15), the cost information calculated by the mobile router (MR2) notified by the IGW cost information notification and the current information If the cost information in the connection with the mobile router (MR1) which is the gateway (IGW) is compared and, as a result, it is determined that the gateway (IGW) should be changed, the wireless link with the access router (AR) 14 is changed. The mobile router (MR2) 4 ′, which is another MR that is established and constitutes the same ad hoc network 100, is selected as a new IGW (step S16), and an IGW selection notification is transmitted to the new IGW (MR2) 4 ′ (step S17). ), The new IGW (MR2) 4 ′ sends an IGW selection confirmation notification to the access router (AR) 14. That (step S18).

  The new IGW (MR2) 4 'starts the operation as the gateway (IGW) immediately after transmitting the IGW selection confirmation notification (step S19), and transmits the IGW advertisement into the ad hoc network 100 (step S20). MR1 (old IGW) 4 that has been the gateway (IGW) stops the gateway (IGW) operation when receiving the first IGW advertisement from the new IGW (MR2) 4 ′ (step S21), and the old IGW (MR1 ) The transfer of the packet addressed to the access router (AR) 14 arriving at 4 to the new IGW (MR2) 4 ′ is started (step S22).

  When the access router (AR) 14 receives the IGW selection confirmation notification from the new IGW (MR2) 4 ′, the access link (AR) 14 changes the radio link for transmitting the packet addressed to the ad hoc network 100 from the old IGW (MR1) 4 to the new IGW (MR2) 4 ′. Switch to. Until the new IGW (MR2) 4 ′ completes the address update process in the mobile IP, the packet of the mobile IP arrives from the home agent (HA) 16 to the mobile router (MR1) 4 that is the old IGW. Therefore, the destination is changed to the mobile router (MR2) 4 ′, which is the new IGW, and transferred to the new IGW (MR2) 4 ′ (step S23).

  As described above, in the present embodiment, as in the second embodiment, it is possible to dynamically select a mobile router (MR) that provides this Internet gateway function and to change it within an ad hoc network. Further, even when the MR that provides the IGW function is changed, it is possible to prevent the packet from being discarded in the transient state.

Embodiment 4 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, when a new ad hoc network gateway (IGW) is selected and the state shown in FIG. An example of the operation is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 9, descriptions of the wireless access control devices installed at various places are omitted.

  When the access router (AR) 14 can communicate with only one mobile router (MR), the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (steps S31 and S32). Thereafter, the mobile router (MR2) 4 ′, which is another MR constituting the ad hoc network 100, can establish a radio link with the access router (AR) 14 and become a gateway (IGW). Is detected (step S33), the IGW cost when the radio link with the access router (AR) 14 is established is estimated (step S34), and the mobile router (MR1) 4 which is the current gateway (IGW) 4 An IGW cost information notification is transmitted to (current IGW) (step S35).

  When the current IGW (MR1) receives the IGW cost information notification from the mobile router (MR2) 4 ′ (step S35), the cost information calculated by the mobile router (MR2) notified by the IGW cost information notification and the current gateway If the cost information in the connection with the mobile router (MR1) that is (IGW) is compared and, as a result, it is determined that the gateway (IGW) should be changed, any MR that can be another IGW is replaced with the new IGW. (Step S36). In the example of FIG. 9, the mobile router (MR2) 4 ′ is selected as a new IGW, and an IGW selection notification is transmitted to the mobile router (MR2) 4 ′ (step S37), and the new IGW (MR2) is sent to the current IGW (MR1). An IGW selection confirmation notification is transmitted (step S38). Upon receiving this IGW selection confirmation notification, the current IGW (MR1) 4 transmits an IGW switching notification to the access router (AR) 14 (step S39), and then stops communication with the access router (AR) 14 (step S40). ), The wireless link with the access router (AR) 14 is released, and the packet addressed to the access router (AR) 14 that has arrived at the mobile router (MR1) 4 that is the current IGW is released to the mobile router (MR2) that is the new IGW. 4 '(step S41).

  The new IGW (MR2) 4 ′ starts to establish a radio link with the access router (AR) 14 immediately after transmitting the IGW selection confirmation notification (step S42), and the radio link with the access router (AR) 14 is started. Until the packet transfer is possible, the packet addressed to the access router (AR) 14 transferred from the current IGW (MR1) 4 is buffered (step S43).

  When the access router (AR) 14 receives the IGW switching notification from the mobile router (MR1) 4 (old IGW) that was the gateway (IGW) before, the access router (AR) 14 changes the connection destination of the wireless link from the old IGW (MR1) 4 to the new IGW. Switch to (MR2) 4 'and establish a radio link with the new IGW (MR2) 4' (step S48). Also, from the time when the IGW switching notification is received from the old IGW (MR1) 4 until the new IGW (MR2) 4 ′ completes the address update process in the mobile IP, the home agent (HA) 16 Since a mobile IP packet arrives at a certain mobile router (MR1) 4, this destination is changed to the new IGW (MR2) 4 ′ and buffered, and a radio link with the new IGW (MR2) is established. After that, the buffered mobile IP packet (step S44) is transferred to the new IGW (MR2) (step S45).

  The new IGW (MR2) 4 ′ transmits an IGW advertisement into the ad hoc network 100, and advertises to each mobile router (MR) that the gateway (IGW) has been switched to the mobile router (MR2) 4 ′ (step S46). At the same time, after the radio link with the access router (AR) 14 is established, the buffered packet for the access router (AR) 14 is transmitted (step S49).

  When the first IGW advertisement is received from the new IGW (MR2) 4 ′, the old IGW (MR1) 4 identifies itself as a gateway (after receiving a prescribed number of IGW advertisements or after a prescribed time has elapsed). The transfer of the packet addressed to the access router (AR) 14 assumed to be IGW) to the new IGW (MR2) is stopped (step S47).

  As described above, a mobile router that constitutes an ad hoc network and that is not a gateway itself detects that a wireless link used for connection with an access router can be established, and functions as a gateway to other mobile routers. The gateway cost is calculated to the mobile router that is the current gateway, and the mobile router is the gateway reported by the other mobile router. Comparing the cost with the gateway cost of oneself, selecting a mobile router that is suitable for providing a gateway function within an ad hoc network, and succeeding the mobile router that provides the current gateway function Selection Instructed the mobile router to start providing the gateway function of the ad hoc network and stops providing the gateway function by itself, thereby making one mobile router in the ad hoc network as a gateway to the external network. The mobile router (MR) that provides this Internet gateway function can be dynamically selected and changed within the ad hoc network, and the MR that provides the IGW function is changed. Sometimes, it is possible to prevent the packet from being discarded in the transient state.

Embodiment 5. FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, the ad hoc network gateway (IGW) is newly selected in the system shown in FIG. An example of the operation when the state shown in FIG. 2 is reached is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 10, descriptions of wireless access control devices installed in various places are omitted.

  When the access router (AR) 14 can communicate with a plurality of mobile routers (MR), the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (step S51), and then the ad hoc It is detected that the mobile router (MR2) 4 ′, which is another MR constituting the network 100, has established a wireless link with the access router (AR) 100 and can become a gateway (IGW). Then (step S52), a radio link with the access router (AR) 14 is established, the IGW cost is estimated, and an IGW cost information notification is transmitted to MR1 (current IGW) 4, which is the current gateway (IGW) ( Step S53).

  When the current IGW (MR1) 4 receives the IGW cost information notification from the mobile router (MR2) 4 ′ (step S53), the cost information calculated by the mobile router (MR2) notified by the IGW cost information notification and the current Comparing the cost information in connection with the mobile router (MR1), which is the gateway (IGW), and, as a result, determining that the gateway (IGW) should be changed, establishes a radio link with the access router (AR) 14 Then, one of the other MRs constituting the same ad hoc network is selected as the new IGW (in the example of the figure, the mobile router (MR2) 4 ′ is selected) (step S54), and the new IGW (MR2) 4 ′ is selected. An IGW selection notification is transmitted (step S55), and the new IGW (MR2) transmits an IGW selection confirmation notification to the current IGW (MR1) 4. (Step S56). Upon receiving this IGW selection confirmation notification, the current IGW (MR1) 4 transmits an IGW switching notification to the access router (AR) 14 (step S57), and then stops communication with the access router (AR) 14 (step S58). , The radio link with the access router (AR) 14 is released, and the packet addressed to the access router (AR) 14 that has arrived at the mobile router (MR1) 4 (old IGW), which has been the gateway (IGW), is sent to the new IGW. (MR2) Transfer to 4 '(step S59).

  The new IGW (MR2) 4 ′ starts the operation as the gateway (IGW) immediately after transmitting the IGW selection confirmation notification (step S56) (step S60), and transmits the IGW advertisement into the ad hoc network 100 (step S61). ). When the old IGW (MR1) 4 receives the first IGW advertisement from the new IGW (MR2) 4 ′ (step S61), the IGW operation is stopped and transfer to the new IGW (MR2) is started (step 59). .

  When the access router (AR) 14 receives the IGW switching notification from the old IGW (MR1) (step S57), the access router (AR) 14 transmits a radio link for transmitting a packet addressed to the ad hoc network 100 from the old IGW (MR1) 4 to the new IGW (MR2). ) Switch to 4 '. Until the new IGW (MR2) 4 ′ completes the address update process in the mobile IP, the mobile IP packet arrives from the home agent (HA) 16 to the mobile router (MR1) 4 which is the old IGW. Then, the destination is changed to the mobile router (MR2) 4 ′, which is the new IGW, and transferred to the new IGW (MR2) (step S60).

  As described above, according to the present embodiment, as in the fourth embodiment, the mobile router (MR) that provides this Internet gateway function is dynamically selected and changed within the ad hoc network. Further, even when the MR that provides the IGW function is changed, it is possible to prevent the packet from being discarded in the transient state.

Embodiment 6 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, the operation when a new ad hoc network gateway (IGW) is selected to enter the state shown in FIG. An example of this is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 11, descriptions of wireless access control devices installed in various places are omitted.

  When the access router (AR) 14 can communicate with only one MR, the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (steps S65 and S66), and then the ad hoc It is detected that the mobile router (MR2) 4 ′, which is another MR constituting the network 100, has established a wireless link with the access router (AR) 14 and can become a gateway (IGW). (Step S67), the IGW cost when the radio link with the access router (AR) 14 is established is estimated (step S68), and as a result, the current gateway becomes a new gateway (IGW). More suitable than the mobile router (MR1) 4 (current IGW) which is a gateway (IGW) Judging transmits IGW ads into ad-hoc network for candidacy to the gateway (IGW) a (candidacy) (step S69). Immediately thereafter, the mobile router (MR2) 4 '(new IGW) newly running as a gateway (IGW) starts to establish a radio link with the access router (AR) 14 (step S70). At this time, the state where the mobile router (MR1) 4 is used as the gateway (IGW) without changing the gateway (IGW) in other MRs continues.

  The current IGW (MR1) 4 receives an IGW advertisement run by another MR to the gateway (IGW) (step S69), and the IGW cost of the new IGW (MR2) 4 ′ notified by the IGW advertisement and the current IGW (MR1) ), And decides to delegate the IGW function to the new IGW (MR2) (step S71), sends an IGW switching notification to the access router (AR) 14 (step S72), and the own IGW The operation is stopped (step S73), the communication with the access router (AR) 14 is stopped, the radio link with the access router (AR) 14 is released, and the mobile router (MR1) that has been the gateway (IGW) until now. Starts forwarding packets addressed to access router (AR) 14 arriving at 4 (old IGW) to new IGW (MR2) 4 ′ Step S74).

  The new IGW (MR2) 4 ′ starts to try to establish a radio link with the access router (AR) 14 immediately after transmitting the candidate IGW advertisement (step S69) to the gateway (IGW) (step S70). The packet addressed to the access router (AR) transferred from the old IGW (MR1) is buffered until the wireless transfer with the router (AR) 14 is established and packet transfer is possible (step S75). When the wireless link with the router (AR) 14 is established, operation as a gateway (IGW) is started (step S76), and the buffered packet for the access router (AR) 14 is transmitted (step S77). The ad hoc network 100 displays an IGW advertisement indicating that it is a gateway (IGW). It begins to cycle sent to.

  When the access router (AR) 14 receives the IGW switching notification from the old IGW (MR1) 4 (step S72), the access router (AR) 14 switches the connection destination of the radio link from the old IGW (MR1) to the new IGW (MR2) (step S78). And establish a radio link with the new IGW (MR2). Also, from the time when the IGW switching notification is received from the old IGW (MR1) 4 until the new IGW (MR2) 4 ′ completes the address update process in the mobile IP, the home agent (HA) Since a mobile IP packet arrives at a certain mobile router (MR1) 4, this destination is changed to the new IGW, which is a mobile router (MR2) 4 ′, and is buffered. After the wireless link is established, the buffered mobile IP packet is transferred to the new IGW (MR2) (step S79).

  When the first IGW advertisement is received from the new IGW (MR2) 4 ′, the old IGW (MR1) 4 identifies itself as a gateway (after receiving a prescribed number of IGW advertisements or after a prescribed time has elapsed). Transfer of the packet addressed to the access router (AR) 14 designated as (IGW) to the new IGW (MR2) 4 ′ is stopped (step S80).

  As described above, in the present embodiment, when the mobile router constituting the ad hoc network operates as a gateway, the mobile router advertises its own gateway cost in the ad hoc network, and the other mobile routers Compare the gateway cost advertised by the mobile router that is the gateway with the gateway cost of its own, determine that the gateway cost of its own is optimal, and that it is appropriate for itself to provide the gateway function within the ad hoc network, The mobile router that has run for the gateway function in the ad hoc network, advertises its own gateway cost into the ad hoc network, and provided the gateway function in the ad hoc network, Compare the gateway cost of yourself with the gateway cost obtained from the contents advertised by the mobile router that has run for the gateway function, and determine that the gateway cost you own is not superior and provide the gateway function The mobile router (MR) that provides the Internet gateway function is dynamically selected and changed within the ad hoc network. Further, even when the MR that provides the IGW function is changed, it is possible to prevent the packet from being discarded in the transient state.

Embodiment 7 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, the ad hoc network gateway (IGW) is newly selected in the system shown in FIG. An example of the operation when the state shown in FIG. 2 is reached is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2, and FIG. 12, descriptions of wireless access control devices installed in various places are omitted.

  When the access router (AR) 14 can communicate with a plurality of MRs, the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (step S85), and then the ad hoc network 100 is configured. The mobile router (MR2) 4 ′, which is another MR, establishes a wireless link with the access router (AR) 14 (step S86), and is in a state where it can become a gateway (IGW). Upon detection, a wireless link with the access router (AR) 14 is established and the IGW cost is estimated. As a result, the mobile router (IGW), which is the current gateway (IGW), becomes a new gateway (IGW). MR1) If determined to be more appropriate than 4 (current IGW) (step S87), To candidacy to gateways (IGW) into the ad-hoc network to send IGW advertising (candidacy) (step S88). At this time, the state where the mobile router (MR1) 4 is used as the gateway (IGW) without changing the gateway (IGW) is maintained in other MRs.

  The current IGW (MR1) 4 receives the IGW advertisement that the mobile router (MR2) 4 ′ has run for the gateway (IGW) (step S88), and is newly notified to the gateway (IGW) that is notified by the IGW advertisement. When the IGW cost of (MR2) 4 ′ (new IGW) is compared with the IGW cost of the current IGW (MR1) and it is decided to delegate the IGW function to the new IGW (MR2) (step S89), the access router (AR) The IGW switching notification is transmitted to 14 (step S90).

  The new IGW (MR2) 4 ′ starts the packet transfer operation from the access router (AR) 14 immediately after transmitting the candidate IGW advertisement to the gateway (IGW) (step S88) (step S91). The IGW advertisement that is the gateway (IGW) is periodically transmitted into the ad hoc, and the operation as the gateway (IGW) is started when the first IGW advertisement is transmitted (step S92) (step S93).

  When the access router (AR) 14 receives the IGW switching notification from the mobile router (MR1) 4 (old IGW) that has been the gateway (IGW) until now (step S90), the access router (AR) 14 changes the connection destination of the radio link to the old IGW (MR1). ) 4 is switched to the new IGW (MR2) 4 ′ (step S94). Also, from the time when the IGW switching notification is received from the old IGW (MR1) 4 to the time when the new IGW (MR2) completes the address update process in the mobile IP, the home agent (HA) previously receives the gateway (IGW). Since the mobile IP packet arrives at the mobile router (MR1) 4 (old IGW), the destination is changed to the mobile router (MR2) 4 ′, which is the new IGW, and the mobile IP packet is updated. Transfer to the IGW (MR2) (step S94).

  The old IGW (MR1) 4 receives the first IGW advertisement from the new IGW (MR2) 4 ′ (step 88), and after a certain time (after receiving a predetermined number of IGW advertisements or after a specified time elapses). The transfer of the packet addressed to the access router (AR) 14 assuming itself as the gateway (IGW) to the new IGW (MR2) 4 ′ is stopped (step S95).

  As described above, in the present embodiment, as in the sixth embodiment, it is possible to dynamically select a mobile router (MR) that provides this Internet gateway function and change it within the ad hoc network. Further, even when the MR that provides the IGW function is changed, it is possible to prevent the packet from being discarded in the transient state.

Embodiment 8 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, the operation when a new ad hoc network gateway (IGW) is selected to enter the state shown in FIG. An example of this is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 13, descriptions of the wireless access control devices installed at various places are omitted.

  In a state where the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (step S100), thereafter, the access router (AR) 14 and the mobile router (MR1) which is the current gateway (IGW). 4, the mobile router (MR1) 4 transmits an IGW advertisement whose IGW cost has been updated into the ad hoc network 100 (step S101). As a result, when other MRs constituting the ad hoc network 100 can establish a wireless link with the access router (AR) 14 and become a gateway (IGW), as described above, the gateway (IGW) selection operation is executed, and a new gateway (IGW) operates (step S102).

  Although FIG. 13 shows a case where the access router (AR) 14 can communicate with only one mobile router (MR), the same applies when the access router (AR) 14 can communicate with a plurality of mobile routers (MR). When the deterioration of the quality of the radio link between the access router (AR) 14 and the current IGW (MR1) 4 is detected, the current IGW (MR1) 4 transmits an IGW advertisement with updated IGW cost into the ad hoc network 100. As a result, a new gateway (IGW) is selected.

  As described above, in the present embodiment, when the mobile router operating as a gateway reduces the gateway cost due to deterioration of the quality of the radio link, etc., the gateway cost is lowered and advertised into the ad hoc network. By prompting other mobile routers constituting the ad hoc network to stand as gateways, the mobile router (MR) that provides this Internet gateway function is dynamically selected as in the sixth and seventh embodiments, and In the ad hoc network, the packet can be changed, and even when the MR that provides the IGW function is changed, the packet can be prevented from being discarded in the transient state.

Embodiment 9 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. 13 and a home agent (HA) 16 that performs mobile IP processing, the operation when a new ad hoc network gateway (IGW) is selected to enter the state shown in FIG. An example of this is shown in the sequence diagram of FIG. In FIG. 1, FIG. 2 and FIG. 14, descriptions of the wireless access control devices installed in various places are omitted.

  In the ad hoc network 100, in the state where the mobile router (MR1) 4 is a gateway (IGW) (step S110), after that, another MR configuring the ad hoc network 100 is a mobile router (IGW) which is the current gateway (IGW). MR1) Several MRs that can provide operation as a gateway (IGW) upon detecting a continuous absence of IGW advertisements that should have been periodically transmitted from 4 (current IGW) (step S111) Transmits an IGW advertisement (candidate) into the ad hoc network 100 in order to run as a candidate for the gateway (IGW) (step S112). Thereafter, the mobile router (MR) whose candidacy is not finally denied starts operation as a gateway (IGW) (step S113). At this point in time, the mobile router (MR1) 4 that has been the gateway (IGW) before is used as the gateway (IGW) without changing the gateway (IGW) in other MRs. Communication between the ad hoc network 100 and the access router (AR) 14 is not possible.

  The new IGW (MR2) 4 ′ selected from the plurality of MRs starts to periodically transmit an IGW advertisement indicating that it is a gateway (IGW) into the ad hoc network 100 (step S114), and configures the ad hoc network 100. The other MR recognizes the mobile router (MR2) 4 ′ as a new gateway (IGW) (step S115).

  FIG. 15 shows an example in which another MR denies a candidate for a certain MR. Other MRs constituting the ad hoc network 100 detect continuous lack of IGW advertisements that should be periodically transmitted from the mobile router (MR1) 4 (current IGW) which is the current gateway (IGW) (step S120). ), MR (MR2) 4 ′, which is determined to be more appropriate to be the gateway (IGW) than the MR (MR3) 4 ″ previously running for the gateway (IGW), is the mobile that has run for the gateway (IGW) first. The IGW operation (step S121) of the router (MR3) 4 ″ is denied, and an IGW advertisement (candidate candidate) is transmitted into the ad hoc network 100 in order to provide the IGW operation (step S122). At this time, the state where the mobile router (MR1) 4 that was the gateway (IGW) is still used without changing the gateway (IGW) in other MRs is still in use, but the ad hoc network 100 and the access are maintained. Communication with the router (AR) 14 is not possible.

  The mobile router (MR2) 4 ′, which is a new IGW that was selected by the gateway (IGW) without being denied after a plurality of MRs run, ad hoc an IGW advertisement indicating that it is the gateway (IGW). (Step S123), other MRs constituting the ad hoc network 100 recognize the mobile router (MR2) 4 ′ as a new gateway (IGW) (step S124).

  As described above, in this embodiment, when the mobile router constituting the ad hoc network operates as a gateway, the mobile router periodically advertises its own gateway cost in the ad hoc network. The mobile router compares the gateway cost advertised by the mobile router that is the gateway with its own gateway cost, and the current mobile router's gateway cost is more optimal than its own gateway cost. In the determined state, the mobile router that provides the gateway function is monitored to periodically advertise the gateway cost in the ad hoc network, and if the periodic advertisement stops, Or The mobile router candid to provide the gateway function in the ad hoc network, advertises its own gateway cost into the ad hoc network, and other mobile routers in the ad hoc network provide the gateway cost and gateway function of its own Compared with the gateway cost obtained from the content advertised by the mobile router that has been elected, it has been determined that it does not provide the gateway function, and the candidate mobile router was selected as the gateway to the external network, A mobile router (MR) that provides this Internet gateway function can be dynamically selected and changed within an ad hoc network.

Embodiment 10 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. FIG. 16 shows an example of the operation when the gateway (IGW) of the ad hoc network is not switched in the system of FIG. 1, which is configured by the mobile agent 13 and the home agent (HA) 16 that performs mobile IP processing. . In FIG. 1 and FIG. 16, the description of the radio access control apparatus installed in each place is omitted.

  In a state where the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (step S130), after that, the mobile router (MR2) 4 ′, which is another MR configuring the ad hoc network 100, When it is detected that a wireless link with the access router (AR) 14 has been established to become a gateway (IGW) (step S131), a wireless link with the access router (AR) 14 is established. If the mobile router (MR1) 4 that is the current gateway (IGW) is more appropriate than the new gateway (IGW), the IGW cost is estimated (step S132). When judging (step S133), the sign to the gateway (IGW) The not carried out, IGW ads do not send.

  As described above, in the present embodiment, one mobile router in the ad hoc network operates as a gateway, and thereafter, other mobile routers constituting the ad hoc network establish a wireless link with the access router. As a result of calculating the IGW cost when establishing a wireless link with the access router by detecting that it is possible to establish and become a gateway (IGW), rather than being a new gateway itself When it is determined that the mobile router that is the current gateway is more appropriate, the mobile router that provides this Internet gateway function (no IGW advertisement is not sent because the candidate for the gateway (IGW) is not sent). MR) is dynamically selected to optimize the current gateway If the mobile router is optimal, it can be left as it is, or if there is a mobile router that is more appropriate than the mobile router that is the current gateway, it can be changed within the ad hoc network. Even when the MR to be provided is changed, the packet can be prevented from being discarded in the transient state.

Embodiment 11 FIG.
The mobile router (MR) 4 and the radio access control device 3 mounted on the high-speed moving body 1 and the access router (AR) 14 and the radio access control device installed in the base station 10 as described in the first embodiment. FIG. 17 is a sequence diagram illustrating an example of an operation when the ad hoc network gateway (IGW) is not switched in the system of FIG. 1, which is configured by the mobile agent 13 and the home agent (HA) 16 that performs mobile IP processing. . In FIG. 1 and FIG. 17, the description of the radio access control apparatus installed in each place is omitted.

  In a state where the mobile router (MR1) 4 in the ad hoc network 100 is operating as a gateway (IGW) (step S140), thereafter, the access router (AR) 14 and the mobile router (MR1) which is the current gateway (IGW). The current IGW (MR1) 4 transmits an IGW advertisement in which the IGW cost is updated to the ad hoc network 100 by detecting a deterioration in the quality of the radio link with the 4 (current IGW) (step S141). As a result, when other MRs constituting the ad hoc network 100 can establish a wireless link with the access router (AR) 14 and become a gateway (IGW), as described above, the gateway The selection operation of (IGW) is executed, and a new gateway (IGW) is established (step S142).

  At this time, if the quality of the radio link between the access router (AR) 14 and the current IGW (MR1) 4 is restored, the current IGW (MR1) 4 can run as an IGW cost of the current IGW (MR1) 4 The IGW cost is compared, the IGW function is determined not to be delegated (step S143), the IGW advertisement whose IGW cost is updated to the latest value is transmitted into the ad hoc network (step S144), and another MR gateway The candidate for (IGW) is rejected (step S145), and the operation of the gateway (IGW) is continued.

  In the above description, the case where the quality is restored after the quality degradation once has been described as an example. However, the present embodiment is not limited to this case and includes the case where the quality is not degraded. Shall. For example, when an ad hoc network composed of mobile routers (MR1) 4, (MR2) 4 ′, (MR3) 4 ″ approaches the access router (AR) with the mobile router (MR1) 4 as the head. Even when another mobile router (MR2) 4 ′ detects that the connection with the access router (AR) is possible, the mobile router (MR1) 4 further approaches the access router (AR) so that the mobile router (MR1) In this embodiment, the mobile router (MR1) 4 operates as a gateway (IGW) regardless of the quality degradation. The other mobile router (MR2) 4 ′ is running as a candidate while periodically sending IGW advertisements to the ad hoc network. However, when the mobile router (MR1) 4 currently operating as the gateway (IGW) determines that it is appropriate to provide the gateway function, the gateway of the other mobile router (MR2) 4 ′ All cases where the candidate for (IGW) is rejected and the operation of the gateway (IGW) is continued are included.

  As described above, in the present embodiment, when the mobile router constituting the ad hoc network operates as a gateway and periodically advertises the gateway cost of the ad hoc network in the ad hoc network, When other mobile routers stand to offer gateway functions in ad hoc networks and advertise their own gateway costs into the ad hoc network, when they receive the advertisements, they provide their own gateway costs and gateway functions Compared to the gateway cost obtained from the content advertised by the above mobile router, it is determined that it is appropriate to provide the gateway function. By advertised, the candidate mobile router is denied to operate as a gateway to an external network. Therefore, a mobile router (MR) that provides this Internet gateway function is dynamically selected, and ad hoc It is possible to change in the network, and even when the MR that provides the IGW function is changed, it is possible to prevent the packet from being discarded in the transient state.

It is the block diagram which showed the connection state of the mobile router mounted in the high-speed moving body, the access router provided in the base station, and the home agent. It is the block diagram which showed the connection state of the mobile router mounted in the high-speed moving body, the access router provided in the base station, and the home agent. It is the block diagram which showed the connection state of the mobile router mounted in the high-speed moving body, the access router provided in the base station, and the home agent. It is the block diagram which showed the structure of the mobile network which concerns on this invention. It is the block diagram which showed the structure of the base station which concerns on this invention. It is the block diagram which showed the structure of the radio | wireless access control apparatus and mobile router which were provided in the high-speed moving body which concerns on this invention. It is the sequence diagram which showed operation | movement of the high-speed moving body, base station, and home agent which concern on Embodiment 2 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 3 of this invention. It is the sequence diagram which showed operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 4 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 5 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 6 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 7 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 8 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 9 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 9 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 10 of this invention. It is the sequence diagram which showed the operation | movement of the high-speed mobile body, base station, and home agent which concern on Embodiment 11 of this invention. It is the block diagram which showed the structure of the conventional network.

Explanation of symbols

  1, 1 ', 1 "high-speed mobile body, 2 antennas, 3 radio access control device, 4, 4', 4" mobile router, 5 mobile network, 6 mobile terminal, 10 base station, 12 antenna, 13 radio access control device , 14 access router, 15 Internet / fixed network, 16 home agent, 31 antenna control unit, 32 receiver, 33 radio link quality determination processing unit, 34 transmitter, 35 mobile body position information processing unit, 36 mobile body mobile information processing Unit, 41 wireless link cost determination processing unit, 42 gateway determination processing unit, 43 ad hoc network route information processing unit, 44 IGW advertisement processing unit.

Claims (10)

A plurality of mobile routers that accommodate mobile networks establish wireless links with each other to form an ad hoc network, communicate within the ad hoc network, and can be connected to an access router. An ad hoc network system that operates as a gateway between a network and an external network,
The mobile router is mounted on a mobile unit, establishes a wireless link with an access router connected to an external network, relays packets between the mobile network that accommodates terminals inside the mobile unit and the external network, Periodically check whether or not a wireless link can be established with multiple nearby access routers, calculate the cost information of the available radio link by referring to the check result, and based on the cost information of the radio link Select the right access router,
The access router is connected to the external network and performs packet relay between the mobile router and the external network,
The cost information of the radio link is calculated from the current value of the transmission rate and error rate in the radio link layer, the current position information, the moving direction information, the moving speed information, and the planned moving path information of the mobile unit on which the mobile router is mounted Predicted position after a certain period of time, position information of a radio base station used by the access router for radio link connection with the mobile router, and a performance value of an antenna installed on a mobile unit providing the radio link The performance value of the antenna installed in the base station that provides the radio link, and the communication available time and the average transmission rate that can be provided by the radio link using,
At least one of the mobile router and the access router uses the cost information of the radio link to calculate a gateway cost that serves as a priority index for each mobile router to operate as a gateway in an ad hoc network. Select a mobile router that acts as a gateway in an ad hoc network using cost,
An ad hoc network system characterized by this. At least one of the mobile router and the access router has a current value of a transmission rate and an error rate in a lower layer of the radio link, current position information, moving direction information, and moving speed information of a mobile unit on which the mobile router is mounted. Installed on a mobile unit that provides a wireless link and a predicted position calculated after a certain amount of time and the predicted route information, the position information of the wireless base station that the access router uses for wireless link connection with the mobile router, and The communication performance time and average transmission rate that the wireless link can provide using the performance value of the antenna and the performance value of the antenna installed in the base station that provides the wireless link, and connection with other mobile routers in the ad hoc network Using the number of hops and the current transmission rate and error rate at the radio link layer between mobile routers, Iruruta calculates the gateway cost indicative of priority to operate as a gateway within the ad hoc network selects the mobile router acting as a gateway in the ad hoc network using the gateway costs,
The ad hoc network system according to claim 1. In the ad hoc network system according to claim 1 or 2,
The mobile router that configures the ad hoc network advertises the gateway cost when it operates as a gateway in the ad hoc network, and compares it with the gateway cost obtained from the content advertised by other mobile routers. Among the multiple mobile routers that are part of the same ad hoc network, the gateway cost that it owns is optimal, and it is advisable to provide the gateway function within the ad hoc network. Candidate to provide the gateway function in the network, advertising its own gateway cost into the ad hoc network,
Other mobile routers in the ad hoc network compare themselves with the gateway cost when operating as a gateway and the gateway cost obtained from the content advertised by the mobile router that has run for the gateway function. Without selecting a candidate mobile router as a gateway to the external network,
A gateway selection method characterized by that. In the ad hoc network system according to claim 1 or 2,
When the mobile router that configures the ad hoc network is operating as a gateway, the mobile router periodically advertises its own gateway cost in the ad hoc network,
Other mobile routers should compare the gateway cost advertised by the mobile router, which is the gateway, with the gateway cost they own, and the gateway cost they own is optimal, and it is appropriate that they provide the gateway function within the ad hoc network If it is determined, it candid to provide the gateway function in the ad hoc network, advertises its own gateway cost into the ad hoc network,
The above mobile router that provided the gateway function in the ad hoc network has its own gateway cost compared to the gateway cost obtained from the content advertised by the mobile router that has run for the gateway function. If it determines that the gateway cost is not superior, it stops providing the gateway function, and selects the above-mentioned mobile router as a gateway to the external network.
A gateway selection method characterized by that. In the ad hoc network system according to claim 1 or 2,
When the mobile router that configures the ad hoc network operates as a gateway, the gateway router advertises its own gateway cost periodically in the ad hoc network, and other mobile routers advertise the gateway mobile router Compare the cost with your own gateway cost, and provide the gateway function when it is determined that the current mobile router's gateway cost is more optimal than your own gateway cost and you want to use the current gateway function. Monitoring that the gateway cost is periodically advertised in the ad hoc network from the mobile router, and if the periodic advertisement stops, one of the mobile routers in the ad hoc network Candidate to provide the gateway function in, advertised its own gateway cost into the ad hoc network, and other mobile routers in the ad hoc network have stood to provide their own gateway cost and gateway function Compare with the gateway cost obtained from the content advertised by the mobile router, determine that it does not provide the gateway function, and select the candidate mobile router as the gateway to the external network.
A gateway selection method characterized by that. In the ad hoc network system according to claim 1 or 2,
When mobile routers that make up an ad hoc network are acting as gateways and periodically advertising their own gateway costs in the ad hoc network, other mobile routers provide gateway functions in the ad hoc network If you advertise your gateway cost to the ad hoc network and receive the advertisement, the content of the mobile router that you have appointed to provide the gateway function If it is judged that it is appropriate to provide the gateway function, advertising the gateway cost of own in the ad hoc network, the candidate mobile It denies that the router operates as a gateway to external networks,
A gateway selection method characterized by that. In the ad hoc network system according to claim 1 or 2,
If a mobile router that makes up an ad hoc network determines that it should delegate the provision of the gateway function to another mobile router when it is operating as a gateway, it reduces the gateway cost of the mobile router and Advertise in the network,
Other mobile routers compare the gateway cost advertised by the mobile router that is the gateway with the gateway cost of their own, the gateway cost of their own is optimal, and it is possible for the mobile router to provide the gateway function within the ad hoc network Judging that it is appropriate, and running for the gateway function in the ad hoc network, advertising its own gateway cost into the ad hoc network,
The mobile router that provided the gateway function in the ad hoc network compares its own gateway cost with the gateway cost obtained from the content advertised by the mobile router that has run for the gateway function. Determining that the gateway cost you have is not superior, stop providing the gateway function, and select the candidate mobile router as a gateway to the external network,
A gateway selection method characterized by that. In the ad hoc network system according to claim 1 or 2,
It is assumed that a mobile router that constitutes an ad hoc network and that is not a gateway itself can establish a wireless link used for connection with an access router and provides a gateway function to other mobile routers. The gateway cost of the case, and the gateway cost that is the result of the trial calculation is reported to the mobile router that is the current gateway,
The mobile router, which is a gateway, compares the gateway cost reported from other mobile routers with its own gateway cost, and provides a mobile router that is a suitable successor to provide a gateway function in an ad hoc network. Instructed to start providing the gateway function of the ad hoc network to the mobile router elected as the successor from the mobile router that is elected and presenting the gateway function, and stops providing the gateway function itself By selecting one mobile router in the ad hoc network as the gateway to the external network,
A gateway selection method characterized by that. In the ad hoc network system according to claim 1 or 2,
It is assumed that a mobile router that constitutes an ad hoc network and that is not a gateway itself can establish a wireless link used for connection with an access router and provides a gateway function to other mobile routers. The gateway cost of the case is reported, and the gateway cost that is the result of the trial calculation is reported to the access router to which the mobile router that is the current gateway is connected,
The access router can provide the gateway function in the ad hoc network by comparing the gateway cost reported from the mobile router constituting the ad hoc network with the gateway cost of the mobile router that provides the current gateway function. Select a mobile router that will be the appropriate successor, instruct the mobile router selected as the successor to start providing the ad hoc network gateway function,
The mobile router that provides the current gateway function stops providing the gateway function, and selects one mobile router in the ad hoc network as a gateway to the external network.
A gateway selection method characterized by that. The ad hoc network system according to any one of claims 7 to 9,
In the transient state when the mobile router that provides the gateway function is changed, the mobile router that provides the gateway function after switching, which is recognized by the mobile router that provides the gateway function before switching, is identified with the current identification information of the mobile router that provides the gateway function. By notifying the connected access router, packets arriving at the access router destined for the mobile router that provides the gateway function before switching from the external network are transferred to the mobile router that provides the gateway function after switching. In addition, in order to transfer from an ad hoc network to an external network via an access router, packets that arrive at the mobile router that provides the gateway function before switching are transferred to the mobile router that provides the gateway function after switching. , Game To prevent packet discard due to not resolve the transfer path in a packet forwarding in a transient state when the mobile router that provides way function is changed,
A gateway selection method characterized by that.

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