JP4948104B2 - Access control device and wireless IP telephone system - Google Patents

Description

  The present invention relates to a wireless IP telephone system using wireless LAN technology, and more particularly to a wireless IP telephone system that performs congestion control for each wireless LAN access point.

  FIG. 1 shows a configuration example of a conventional wireless IP telephone system. As shown in FIG. 1, this wireless IP telephone system includes a plurality of wireless LAN access points (hereinafter referred to as wireless APs), a wireless LAN switch that manages a plurality of wireless APs, and a SIP server that performs call control of IP telephones. Including. Further, terminals such as a wireless VoIP terminal exist under the wireless AP, and are connected to the wireless AP. In this system, a voice channel is established between terminals by call connection processing based on SIP, and voice communication by RTP is performed.

The wireless LAN switch has a function that supports handover between the terminal and the wireless AP, a function that distributes the connection from the terminal to the wireless AP, and the like. It is possible to connect to a wireless AP having a sufficient bandwidth while avoiding the AP (for example, see Non-Patent Document 1).
Nikkei Communication, pp. 96 to 103, Nikkei Business Publications, Inc. 2005.7.15

  However, the conventional wireless IP telephone system has the following problems.

  For example, in a state where a large number of terminals are connected to the wireless AP 10 in the system of FIG. 1 and wireless AP resources that are close to the limit are used, the wireless AP 10 exists under the wireless AP 10 but is still connected to the call. It is assumed that a new call connection request for the terminal 1 that does not exist is transmitted from the terminal 2.

  Generally, the resource allocation for each connected terminal in the wireless AP is a best-effort type with no guarantee of quality of service (QoS). Therefore, the resources for the call of the terminal 1 are allocated to the wireless AP 10 in the call connection process. A voice channel is established between the caller terminals 2 and voice communication is performed.

  However, since the wireless AP 10 has used wireless AP resources that are close to the limit before the connection of the terminal 1, when the terminal 1 is connected, the resources of the wireless AP 10 are further consumed, and the wireless AP 10 enters a congestion state. . As a result, not only a good voice quality cannot be obtained at the terminal 1, but also the voice quality at all the terminals originally connected to the wireless AP 10 is lowered, and noise, missing sound, communication disconnection, etc. occur.

  As described above, in the conventional wireless IP telephone system, when a call connection request is made to a terminal under the wireless AP, even if the wireless AP is in a congested state, a call is established to the terminal. There was a problem of adversely affecting all terminals under the wireless AP.

  In addition, there is a technology that limits the number of calls that can be accommodated in a wireless AP in a conventional system consisting of a wireless LAN switch and a wireless AP, but control at the application layer (for example, a layer that performs call control by SIP) Therefore, when the call source terminal fails in the call connection, the call source terminal cannot grasp whether the call connection has failed due to the destination terminal or the wireless AP. Thus, the conventional system has not been able to realize a flexible response at the application layer.

  Furthermore, in the conventional wireless IP telephone system, since it is not possible to perform wireless AP congestion management / control for a terminal in a call, when a terminal is handed over from a connected wireless AP to another wireless AP. Even if another wireless AP uses a wireless AP resource that is close to the limit, the other wireless AP accepts the connection of the terminal that has been handed over. Therefore, another wireless AP that accepts this terminal has the same problem as the wireless AP that accepts an incoming call from the terminal 2 shown in FIG. That is, the call quality of a call of a terminal using the handover destination wireless AP is reduced, or a disconnected state occurs. In addition, when the handed over terminal becomes disconnected, the communication partner terminal cannot know what state the terminal is in, so it can determine whether the disconnected call can be disconnected. There is also a problem that an unnecessary standby state occurs.

  Also, in an environment where multiple wireless APs are arranged adjacent to each other, even if a certain wireless AP is congested, the adjacent wireless AP may not be congested. There is a request to continue communication using an adjacent wireless AP.

  The present invention has been made in view of the above points, and an object of the present invention is to solve the problems of the prior art and provide a technique for performing control according to the resource state of the wireless AP.

The present invention is an access control apparatus in a wireless IP telephone system having a plurality of wireless APs and VoIP call control means, and triggered by the connection from the terminal to a certain wireless AP, the terminal in the data link layer A lower layer that receives a terminal registration request including lower layer identification information that is identification information and wireless AP identification information from the wireless AP, and registers the identification information of the wireless AP in the storage unit in association with the lower layer identification information A terminal registration request including registration means, and upper layer identification information which is identification information used in call control of the terminal and the lower layer identification information, is received from the VoIP call control means, and the upper layer identification information is received from the lower layer Upper layer registration means for registering in the storage means in association with identification information, and receiving a call connection request related to an incoming call to the terminal or an outgoing call from the terminal. Triggered by a resource reservation request from the VoIP call control means, the storage means is searched based on higher layer identification information of the terminal included in the request to detect the wireless AP accommodating the terminal, and the wireless AP And resource control means for controlling the allocation of communication resources to the terminal and storing the state information indicating the state of the terminal in the storage means in association with the lower layer identification information and the upper layer identification information. The VoIP call control means makes a call connection between the terminal and the partner terminal, stores state information indicating that communication resources for the terminal have been secured, and stores the terminal in the partner terminal. When the terminal moves from the subordinate of the connected wireless AP to the subordinate of the destination wireless AP, which is another wireless AP, In response to the connection from the terminal to the destination wireless AP, the lower layer registration means sends a terminal registration request including lower layer identification information of the terminal and identification information of the destination wireless AP to the movement Received from the destination wireless AP, the identification information of the destination wireless AP is registered in the storage means in association with the lower layer identification information and the upper layer identification information, and the resource control means has communication resources for the terminal By confirming that the status information indicating that it has been secured is stored in the storage means, the wireless AP is assigned to the terminal without receiving a request from the VoIP call control means. The communication resource is released, and further, it is determined whether or not the destination wireless AP is in a congested state. The AP secures communication resources for the terminal, and when the destination wireless AP is in a congested state, transmits a radio link disconnection request with the terminal to the destination wireless AP without securing communication resources. It is comprised as an access control apparatus characterized by the above.
The access control device retains the number of times communication resources for the terminal have failed to be secured because another wireless AP connected to the terminal that has disconnected the wireless link with the wireless AP is in a congested state. If the number of failed communication resource allocations does not reach the predetermined number, a wireless link disconnection request is transmitted to the wireless AP that has failed to secure communication resource, and communication resource allocation fails. When the number of times reached the predetermined number, a handover failure notification may be transmitted to the VoIP call control means.
Further, the present invention is an access control apparatus in a wireless IP telephone system having a plurality of wireless APs and VoIP call control means, and the data link layer is triggered by the connection from a terminal to a certain wireless AP. A terminal registration request including lower layer identification information that is terminal identification information and wireless AP identification information is received from the wireless AP, and the identification information of the wireless AP is associated with the lower layer identification information and registered in the storage unit. A terminal registration request including lower layer registration means, upper layer identification information that is identification information used in call control of the terminal, and the lower layer identification information is received from the VoIP call control means, and the upper layer identification information is received. An upper layer registration means for registering in the storage means in association with lower layer identification information, and a call connection request related to an incoming call to the terminal or an outgoing call from the terminal. The resource reservation request for the terminal is received from the received VoIP call control means, the storage means is searched based on the upper layer identification information of the terminal included in the request, and the wireless AP accommodating the terminal is detected. Resource control means for performing communication resource allocation control for the terminal in the wireless AP and storing state information indicating the state of the terminal in the storage means in association with the lower layer identification information and the upper layer identification information And the VoIP call control means performs call connection between the terminal and the counterpart terminal, and the terminal is under communication with the connected wireless AP in a state where the terminal is communicating with the counterpart terminal. The resource control means is assigned to the terminal in the wireless AP when the wireless AP moves under the control of the first destination wireless AP that is another wireless AP. Releasing the communication resources, storing the state information indicating that the terminal is undergoing handover in the storage means, and further determining whether or not the first destination wireless AP is in a congested state, When the first destination wireless AP is in a congested state, the access control device transmits a radio link disconnection request with the terminal to the first destination wireless AP, and receives the radio link disconnection request. When the terminal that has received a radio link disconnection instruction from one destination wireless AP has made a connection to the second destination wireless AP, the lower layer registration means performs the lower layer identification information of the terminal and the first 2 receives a terminal registration request including the identification information of the second destination wireless AP from the second destination wireless AP, and corresponds the identification information of the second destination wireless AP to the lower layer identification information and the upper layer identification information. Add the memory The resource control means receives a request from the VoIP call control means by confirming that the status information indicating that the terminal is in handover is stored in the storage means. Instead, it may be configured as an access control device that secures communication resources related to the terminal for the second destination wireless AP.
The access control device holds the number of times communication resources related to the terminal have failed to be secured because another wireless AP connected to the terminal that has disconnected the wireless link with the wireless AP is in a congested state. If the number of failed communication resource allocations does not reach the predetermined number, a wireless link disconnection request is transmitted to the wireless AP that has failed to secure communication resource, and communication resource allocation fails. When the number of times reached the predetermined number, a handover failure notification may be transmitted to the VoIP call control means.
The present invention is also a wireless IP telephone system comprising a VoIP call control means and the access control device, wherein the VoIP call control means is a transfer destination of a call connection request related to an incoming call to the terminal. When the handover failure notification is received from the transfer destination table recording the identification information of the destination terminal and the access control device, the identification information of the transfer destination terminal is acquired from the transfer destination table, and the identification information is And a means for transmitting a call connection request to the transfer destination terminal. The wireless IP telephone system may be configured.
Further, the present invention is an access control apparatus in a wireless IP telephone system having a wireless AP and a VoIP call control means, and triggered by the connection from the terminal to the wireless AP, the terminal in the data link layer Lower layer registration that receives a terminal registration request including lower layer identification information and wireless AP identification information as identification information from the wireless AP, and registers the wireless AP identification information in the storage unit in association with the lower layer identification information And a terminal registration request including upper layer identification information, which is identification information used in call control of the terminal, and the lower layer identification information, is received from the VoIP call control means, and the upper layer identification information is received from the lower layer Upper layer registration means for registering in the storage means in association with identification information, and receiving a call connection request related to an incoming call to the terminal or an outgoing call from the terminal Receiving the resource status inquiry from the VoIP call control means, searching the storage means based on the upper layer identification information of the terminal included in the inquiry to detect the wireless AP accommodating the terminal, A determination unit that obtains a determination result as to whether or not the AP is in a congested state, and has a notification unit that notifies the VoIP call control unit that the wireless AP is congested when the AP is in a congested state. You may comprise as an access control apparatus. The registration of the upper layer identification information in association with the lower layer identification information in the storage means means that the upper layer identification information is associated with the upper layer identification information and the lower layer identification information stored in advance in the storage means. It also includes recording information indicating that has entered the registration state.

  The storage means of the access control device stores the wireless AP identification information, the resource upper limit value of the wireless AP, and the resource amount being used in the wireless AP in association with each other, and the notification means stores the wireless AP's resource information. A determination unit that determines whether or not the wireless AP is in a congestion state based on a resource upper limit value, a resource amount in use, and a required resource amount for the terminal included in the resource state inquiry may be included.

  The present invention is also a wireless IP telephone system having the access control device and the VoIP call control means, wherein the VoIP call control means is congested with the wireless AP as a response to the resource status inquiry. When a notification to the effect is received from the access control device, the call connection request is suspended, the terminal that transmitted the call connection request is notified that the communication path is congested, and the wireless AP is congested. It can also be configured as a wireless IP telephone system characterized by having call control means for making a call connection to a destination terminal upon receiving from the access control device a notification that the state has been recovered.

  The present invention relates to an access control method in a wireless IP telephone system having a wireless AP, a VoIP call control means, and an access control device, wherein the access control device is triggered by a connection from a terminal to the wireless AP. Receiving a terminal registration request including lower layer identification information, which is identification information of the terminal in the data link layer, and wireless AP identification information from the wireless AP, and associating the wireless AP identification information with the lower layer identification information A lower layer registration step for registering in the storage means, and the access control apparatus sends a terminal registration request including higher layer identification information, which is identification information used for call control of the terminal, and the lower layer identification information, to the VoIP call control And receiving the upper layer identification information in association with the lower layer identification information and registering it in the storage means. And the VoIP call control means receives a call connection request relating to an incoming call to the terminal or an outgoing call from the terminal, and transmits an inquiry of a resource state necessary for the call of the terminal to the access control apparatus. A resource status inquiry step, wherein the access control device searches the storage means based on upper layer identification information of the terminal included in the inquiry to detect the wireless AP accommodating the terminal, and the wireless AP is congested A determination step of obtaining a determination result as to whether or not the wireless AP is in a congested state, a notification step of notifying the VoIP call control means that the wireless AP is congested, and the VoIP call control means comprising: It can also be configured as an access control method characterized by having a call control step for executing call control in response to the AP being congested.

  Further, the present invention is an access control apparatus in a wireless IP telephone system having a plurality of wireless APs and VoIP call control means, and the data link layer is triggered by the connection from a terminal to a certain wireless AP. A terminal registration request including lower layer identification information that is terminal identification information and wireless AP identification information is received from the wireless AP, and the identification information of the wireless AP is associated with the lower layer identification information and registered in the storage unit. A terminal registration request including lower layer registration means, upper layer identification information that is identification information used in call control of the terminal, and the lower layer identification information is received from the VoIP call control means, and the upper layer identification information is received. An upper layer registration means for registering in the storage means in association with lower layer identification information, and a call connection request related to an incoming call to the terminal or an outgoing call from the terminal. Triggered by the resource reservation request from the received VoIP call control means, the storage means is searched based on the upper layer identification information of the terminal included in the request to detect the wireless AP accommodating the terminal, Resource control means for performing communication resource allocation control for the terminal in the wireless AP, and the VoIP call control means performs call connection between the terminal and the counterpart terminal, and the terminal is communicating with the counterpart terminal. In this state, when the terminal moves from a connected wireless AP to a destination wireless AP that is another wireless AP, the terminal is connected to the destination wireless AP. As a trigger, the lower layer registration means receives a terminal registration request including lower layer identification information of the terminal and identification information of the destination wireless AP from the destination wireless AP, and AP identification information is registered in the storage means in association with the lower layer identification information and the upper layer identification information, and the resource control means receives the request from the VoIP call control means without receiving a request from the VoIP call control means. As an access control device that releases resources allocated to the terminal and secures communication resources for the terminal in the destination wireless AP when the destination wireless AP is not congested It can also be configured.

  The resource control means obtains a determination result as to whether or not the destination wireless AP is in a congestion state before securing resources in the destination wireless AP, and the destination wireless AP is in a congestion state In this case, the access control apparatus may transmit a wireless link disconnection request with the terminal to the destination wireless AP.

  In this configuration, when the terminal that has received the wireless link disconnection instruction from the destination wireless AP that has received the wireless link disconnection request has made a connection to another wireless AP, the lower layer registration unit includes: The identification information of the other wireless AP is registered in the storage unit in association with the lower layer identification information and the upper layer identification information, and the resource control unit, when the other wireless AP is not in a congestion state, Resources for the terminal can be secured in other wireless APs.

  In addition, the access control apparatus holds the number of times that the resource reservation has failed because the wireless AP to which the terminal is connected is in a congested state, compares the number of times with a predetermined number of times, and determines the number of times the resource reservation has failed. If the predetermined number of times has not been reached, a wireless link disconnection request is transmitted to the wireless AP that has failed to secure the resource, and if the number of failed resource reservations has reached the predetermined number of times, a handover failure notification is sent. You may make it transmit to the said VoIP call control apparatus.

  In a wireless IP telephone system having the access control device and the VoIP call control means, the VoIP call control means performs call control for the counterpart terminal when the handover failure notification is received from the access control device. It may be.

  The present invention also relates to an access control method in a wireless IP telephone system having a plurality of wireless APs, VoIP call control means, and an access control device, wherein the access control device is connected to a wireless AP from a terminal. As a result, a terminal registration request including lower layer identification information that is identification information of the terminal in the data link layer and wireless AP identification information is received from the wireless AP, and the identification information of the wireless AP is received as the lower layer identification information. A lower layer registration step of registering in the storage means in association with information, and a terminal registration request including the upper layer identification information, which is identification information used in call control of the terminal by the access control device, and the lower layer identification information Is received from the VoIP call control means, and the upper layer identification information is registered in the storage means in association with the lower layer identification information. A recording step, a step in which the VoIP call control means receives a call connection request related to an incoming call to the terminal or an outgoing call from the terminal, and transmits a resource reservation request to the access control apparatus; and Triggered by receiving the resource reservation request, the storage means is searched based on higher layer identification information of the terminal included in the request to detect the wireless AP accommodating the terminal, and the wireless AP A resource control step for performing allocation control of communication resources to the terminal, wherein the VoIP call control means performs a call connection process between the terminal and the partner terminal, and the terminal is in communication with the partner terminal. When the terminal moves from a connected wireless AP to a destination wireless AP that is another wireless AP, the terminal moves to the destination wireless AP. When the connection is established, the destination wireless AP transmits a terminal registration request including lower layer identification information of the terminal and identification information of the destination wireless AP to the access control apparatus, and the terminal registration The access control device that has received the request registers the identification information of the destination wireless AP in the storage means in association with the lower layer identification information and the upper layer identification information, and receives the request from the VoIP call control means. Without receiving, the communication resource allocated to the terminal in the wireless AP is released, and when the destination wireless AP is not congested, the destination wireless AP secures the communication resource for the terminal. It can also be configured as an access control method characterized by this.

  Further, the present invention is an access control apparatus in a wireless IP telephone system having a plurality of wireless APs and VoIP call control means, and the data link layer is triggered by the connection from a terminal to a certain wireless AP. A terminal registration request including lower layer identification information that is terminal identification information and wireless AP identification information is received from the wireless AP, and the identification information of the wireless AP is associated with the lower layer identification information and registered in the storage unit. A terminal registration request including lower layer registration means, upper layer identification information that is identification information used in call control of the terminal, and the lower layer identification information is received from the VoIP call control means, and the upper layer identification information is received. An upper layer registration means for registering in the storage means in association with lower layer identification information, and a call connection request related to an incoming call to the terminal or an outgoing call from the terminal. The resource reservation request for the terminal is received from the received VoIP call control means, the storage means is searched based on the upper layer identification information of the terminal included in the request, and the wireless AP accommodating the terminal is detected. Resource determining means for obtaining a determination result as to whether or not the wireless AP is in a congested state, and when the wireless AP is in a congested state, the access control device disconnects the radio link with the terminal. The lower layer registration is triggered when the terminal that has transmitted a request to the wireless AP and has received a wireless link disconnection instruction from the wireless AP that has received the wireless link disconnection request has connected to another wireless AP. Means for registering the identification information of the other wireless AP in the storage means in association with the lower layer identification information and the upper layer identification information; Configuration may be.

  When the call connection request is related to an incoming call from the counterpart terminal to the terminal, the resource determination unit acquires a determination result as to whether or not the other wireless AP is in a congestion state, and the other When the wireless AP is not in a congested state, the access control apparatus can be configured to transmit a message indicating that resource reservation has been successful to the VoIP call control means.

  In a wireless IP telephone system having the access control device and the VoIP call control means, the VoIP call control means is based on the call connection request in response to receiving a message indicating that the resource reservation is successful. The call connection process can be continued.

Further, in the wireless IP telephone having the access control device and the VoIP call control means, when the call connection request relates to a call from the terminal to the partner terminal, the resource determination means Obtaining a determination result of whether or not a wireless AP is in a congested state, and when the other wireless AP is not in a congested state, the VoIP call control means, based on a call connection request received again from the terminal, A call connection process between the terminal and the partner terminal can be performed.
Further, the access control device holds the number of times that the resource reservation has failed because the wireless AP to which the terminal is connected is in a congested state, compares the number of times with a predetermined number of times, and determines the number of times that the resource reservation has failed. If the predetermined number of times has not been reached, a wireless link disconnection request is transmitted to the wireless AP that has failed in resource reservation, and if the number of failed resource reservations has reached the predetermined number of times, the wireless AP is congested. A message indicating the state may be transmitted to the VoIP call control device.

  The present invention also relates to an access control method in a wireless IP telephone system having a plurality of wireless APs, VoIP call control means, and an access control device, wherein the access control device is connected to a wireless AP from a terminal. As a result, a terminal registration request including lower layer identification information that is identification information of the terminal in the data link layer and wireless AP identification information is received from the wireless AP, and the identification information of the wireless AP is received as the lower layer identification information. A lower layer registration step of registering in the storage means in association with information, and a terminal registration request including the upper layer identification information, which is identification information used in call control of the terminal by the access control device, and the lower layer identification information Is received from the VoIP call control means, and the upper layer identification information is registered in the storage means in association with the lower layer identification information. A recording step, a step in which the VoIP call control means receives a call connection request relating to an incoming call to the terminal or an outgoing call from the terminal, and the access control apparatus reserves a resource reservation for the terminal from the VoIP call control means. Receiving the request, searching the storage means based on the upper layer identification information of the terminal included in the request, detecting the wireless AP accommodating the terminal, and whether or not the wireless AP is in a congested state A resource determination step of obtaining a determination result; a step of transmitting, when the wireless AP is in a congested state, a request for disconnecting a wireless link with the terminal to the wireless AP; and a request for disconnecting the wireless link When the terminal that has received the wireless link disconnection instruction from the wireless AP that has received the connection establishes a connection to another wireless AP, the access control apparatus The wireless AP identification information may be registered in the storage means in association with the lower layer identification information and the upper layer identification information.

  According to the present invention, wireless AP identification information and upper layer identification information that is identification information used in terminal call control are registered in association with each other based on lower layer identification information that is terminal identification information in the data link layer. Since the wireless AP accommodating the target terminal can be detected based on the higher layer identification information used in call control, call control of the terminal corresponding to the higher layer identification information can be realized according to the resource state of the wireless AP. Therefore, when there is a call connection request to a terminal under the wireless AP, if the wireless AP is in a congested state, for example, a busy is transmitted to the transmitting terminal without establishing a call to the terminal. Such a flexible response at the application layer is possible, and the problem of the prior art that adversely affects all terminals under the wireless AP is solved.

  In addition, since flexible support at the application layer is possible, various causes such as notification of the cause of call connection failure, call transfer, call connection after congestion recovery, etc. are provided to the source terminal that has failed in the call connection. It is possible to take correspondence.

  Further, according to the present invention, it is possible to perform handover while performing congestion management / control of a wireless AP for a terminal that is on a call, and the problems of the related art relating to handover are solved.

  Further, according to the present invention, in an environment where a plurality of wireless APs are arranged adjacent to each other, even if the connected wireless APs are congested, if the adjacent wireless APs are not congested, the adjacent wireless APs It is possible to continue communication using the. This also increases the call success probability.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
(System overview)
FIG. 2 shows an example of a system according to the first embodiment of the present invention. The system shown in FIG. 2 is obtained by adding an access controller 30 to the system shown in FIG. The access controller 30 can be provided in place of the wireless LAN switch in FIG. 2 or in the wireless LAN switch.

  The access controller 30 in the system of FIG. 2 has a function of managing the resource allocation state for each terminal for each wireless AP. The SIP server 40 has a function of inquiring the resource state to the access controller in response to the occurrence of VoIP communication and performing call control according to the resource state.

  An outline of the operation of the system according to the present embodiment will be described with reference to FIG. In FIG. 3, it is assumed that the wireless AP 10 is in a congested state and the terminal 1 is under the wireless AP 10 but has not yet been connected. In this state, when a call connection request for the terminal 1 is transmitted from the source terminal 2 to the SIP server 40 (step A), the SIP server 40 calls the access controller 30 to call the terminal 1 that is the destination terminal. Queries the resource status for (step B). The access controller 30 notifies the SIP server 40 that the wireless AP 10 is in a congested state and resources cannot be allocated to the terminal 1 in the wireless AP 10 (step C). The SIP server 40 receives this notification, and transmits busy to the caller terminal 2 as a response to the call connection request in step A (step D).

  As described above, in this embodiment, when the wireless AP is in a congested state, a new call connection is not made, and thus, adverse effects such as voice deterioration on the terminal connected to the wireless AP caused by the new call connection are prevented. it can. In addition, although busy return was demonstrated as a process of the SIP server 40 at the time of congestion, this is only an example and various other processes are possible.

(System operation details)
Next, the operation of the system according to the present embodiment will be described in detail with reference to a sequence diagram. Each sequence diagram appropriately shows the structure of data held in each device. In addition, although the registrar and the SIP server are shown in the sequence diagram, they may be separate devices, or the registrar may be included in the SIP server. This registrar has functions similar to those of a general SIP-based registrar. In each sequence, MSID indicates the MAC address of the terminal, APID indicates the ID of the wireless AP, and URI indicates SIP-URI.

  First, a sequence for registering the VoIP terminal 1 (hereinafter referred to as terminal 1) in the access controller will be described with reference to FIG. The registration process shown in FIG. 4 is automatically performed when the terminal 1 is turned on, for example. Further, at the time shown in FIG. 4, the access controller is registered in the SIP server, and message transmission and reception based on SIP is possible between the access controller and the SIP server.

  In step 1 of FIG. 4, wireless link connection processing and authentication processing in the wireless LAN are performed between the terminal 1 and the wireless AP. Here, the wireless AP acquires and registers the MAC address (MSID) of the terminal 1 (step 2). The wireless AP transmits a terminal registration request including the wireless AP ID (AP01) and the MAC address (MS01) of the terminal 1 to the access controller (step 3). The access controller registers the wireless AP ID (AP01) and the MAC address (MS01) of the terminal 1 received from the wireless AP by storing them in the storage device (step 4). Then, the access controller returns a terminal registration response to the wireless AP (step 5).

  In step 6, the terminal 1 transmits a SIP register message to the registrar. The message to be transmitted includes MS01 and the URI (URI1) of terminal 1. The registrar performs normal register processing and transmits a URI registration request including MS01 and URI1 to the access controller (step 7). The access controller validates the URI by storing URI1 in association with AP01 and MS01 (step 8), and sends a URI registration response to the registrar (step 9). Then, the registrar returns a response to the register message in step 6 to the terminal 1 (step 10).

  In the example described here, the MAC address and URI of the terminal are stored in the access controller in the sequence, but these data are stored in advance in the access controller and only state changes are recorded. It is good. In this case, for example, AP01 is recorded in association with MS01 registered in advance in step 4, and information that URI1 is valid is recorded in association with AP01, MS01, and URI1 in step 8. The same applies to other embodiments.

  Next, processing for deleting the registered terminal 1 from the access controller will be described with reference to FIG. The process shown in FIG. 5 is executed, for example, when the terminal 1 is turned off.

  In step 1 of FIG. 5, the terminal 1 transmits a register message including a registration deletion command to the registrar. The registrar sends a URI deletion request to the access controller (step 2), and the access controller that receives this request invalidates the URI by deleting URI1 from the database (step 3). The access controller returns a URI deletion response (step 4), and the registrar returns a response to the terminal 1 (step 5).

  In Step 6, when the terminal 1 leaves the wireless AP (disconnects the wireless link with the wireless AP), the wireless LAN process is performed, and the wireless AP receives the MSID and deletes the MSID (Step 7). A terminal deletion request is transmitted to the access controller (step 8), and the access controller that has received this deletes AP01 and MS01 from the database (step 9), and returns a terminal deletion response to the wireless AP (step 10).

  Next, with reference to FIGS. 6 to 8, an operation when an incoming request is made from the terminal 2 to the terminal 1 under the wireless AP that is not congested will be described.

  The source terminal 2 transmits a call connection request (INVITE) to the SIP server (step 1). The SIP server that has received the INVITE transmits a QoS reservation request including the source terminal URI (URI2), the destination terminal URI (URI1), and the necessary bandwidth to the access controller (step 2). The access controller searches the database based on the destination URI 1 and extracts the wireless AP having the terminal 1 under control (step 3). Then, a QoS reservation request including MS01 and necessary bandwidth is transmitted to the wireless AP (step 4). The wireless AP reserves a bandwidth for the terminal 1 (step 5), returns a QoS reservation response to the access controller (step 6), and the access controller returns a QoS reservation response to the SIP server (step 7). Thereafter, a sequence based on normal SIP is executed (steps 8 to 12).

  In this example, the wireless AP manages the bandwidth and reserves / reserves the bandwidth, but the access controller has a function to manage the bandwidth of the wireless AP and control resources such as bandwidth reservation / reservation. May be. In this case, messages regarding bandwidth reservation / reservation / release are not transmitted / received between the wireless AP and the access controller, and resource management such as bandwidth reservation / reservation / release is performed within the access controller. The same applies to other embodiments.

  The wireless AP performs timer monitoring, and if the next message (step 16) is not received within a predetermined time, the bandwidth secured in step is released (step 13 in FIG. 7).

  The SIP server that has transmitted and received ACK (steps 11 and 12 in FIG. 6) manages the call between the terminal 1 and the terminal 2 as a busy call. Since the bandwidth between the terminals 1 and 2 is determined at this time, the SIP server transmits a QoS ensuring request to the access controller in step 14 of FIG. Thereafter, a bandwidth (resource) is secured in the wireless AP by the same sequence (step 15 to step 19 in FIG. 7) as the QoS reservation request sequence (step 3 to step 7 in FIG. 6). Voice communication is executed (step 20).

  FIG. 8 is a sequence diagram showing processing when a call is disconnected from the terminal 2 after step 20 of FIG. In steps 21 to 24, the SIP server disconnects the call by performing normal SIP processing. In step 25, the SIP server sends a QoS release request to the access controller. The access controller extracts the corresponding wireless AP (step 26) and transmits a QoS release request to the wireless AP (step 27). The wireless AP releases the bandwidth that has been reserved for the MS01 so far (step 28), returns a QoS release response to the access controller (step 29), and the access controller returns a QoS release response to the SIP server (step 30). .

  9 to 11 are diagrams illustrating a sequence in a case where the terminal 1 under the wireless AP not in the congestion state transmits to the terminal 2. Except for the difference in SIP sequence caused by the exchange of the transmitting terminal and the receiving terminal, the same processing as in FIGS. 6 to 8 is executed, and bandwidth reservation, bandwidth reservation, and bandwidth release are performed.

  Next, an operation example 1 in the case where an incoming request is received from the terminal 2 to the terminal 1 under the congested wireless AP will be described with reference to FIG.

  Steps 1 to 4 in FIG. 12 are the same as steps 1 to 4 in FIG. In step 5 after the wireless AP receives the QoS reservation request from the access controller, the wireless AP has already allocated almost all the bandwidth that can be allocated, and cannot reserve the necessary bandwidth included in the QoS reservation request. judge. Then, the wireless AP returns a QoS reservation response indicating that it is congested to the access controller (step 6). The access controller also returns a similar QoS reservation response to the SIP server (step 7), and the SIP server determines that the wireless AP is congested based on this QoS reservation response, and transmits a busy to the terminal 2 (step 8).

  Next, an operation example 2 in the case where an incoming request is received from the terminal 2 to the terminal 1 under the congested wireless AP will be described with reference to FIGS. The operation example 1 described with reference to FIG. 12 is an example in which the SIP server returns busy to the calling terminal, while the operation example 2 is an example in which the SIP server transfers a call. In this case, it is assumed that a transfer destination table in which a transfer destination terminal corresponding to the terminal is recorded for each terminal in the SIP server. Further, it is assumed that the transfer destination terminal 3 (URI 3) is a VoIP terminal connected to the network by wire.

  Steps 1 to 7 in FIG. 13 are the same as steps 1 to 7 in FIG. When the SIP server receives a QoS reservation response indicating that congestion is occurring, in step 8, the SIP server refers to the transfer destination table and obtains the transfer destination URI 3 corresponding to the terminal 1 (URI 1) that is the destination. Then, the SIP server transmits a QoS reservation request designating the destination URI 3 to the access controller (step 9). The access controller searches for a wireless AP having the terminal 3 of URI 3 under control (step 10), but such a wireless AP does not exist in the database, and a QoS reservation response indicating that fact is returned to the SIP server (step 11). Thereafter, the SIP server performs call connection processing for normal transfer (steps 12 to 16 in FIG. 14), and voice communication is performed between the terminal 3 and the terminal 2 (step 17). When the call is disconnected in steps 18 to 21, the SIP server transmits a QoS release request to the access controller in step 22 (step 22), but the corresponding wireless AP is not found in the access controller (step 23). A QoS release response is transmitted to the SIP server (step 24).

  Next, an operation example 3 in the case where an incoming request is received from the terminal 2 to the terminal 1 under the congested wireless AP will be described with reference to FIG. In the operation example 3, a media server is provided, and after the SIP server receives a QoS reservation message indicating that congestion is present in step 7, the media server and the terminal 2 are connected (steps 8 to 12). After a guidance such as “Cannot connect because of congestion” is sent to the terminal 2 (step 13), the call is disconnected (steps 14 to 17).

  Next, an operation example 4 in the case where an incoming request is received from the terminal 2 to the terminal 1 under the congested wireless AP will be described with reference to FIGS. In the operation example 4, the terminal 1 is in a state where the connection is impossible due to the wireless AP congestion, and a guidance for notifying the terminal 1 to wait until communication becomes possible is sent to the terminal 2, and the congestion of the wireless AP is resolved. When the terminal 1 becomes communicable, the terminal 1 and the terminal 2 are connected.

  In step 7, when the SIP server receives a QoS reservation response indicating congestion, the SIP server sends a QoS reservation + notification request including the outgoing / incoming URI, required bandwidth, and CallID to the access controller (step 8). The QoS reservation + notification request is a message for notifying the wireless AP of the bandwidth for which the QoS reservation is to be made, and requesting that notification be made when there is enough space to secure the bandwidth.

  In step 9, the access controller transmits a QoS reservation + notification request to the corresponding wireless AP. The wireless AP that has received the QoS reservation + notification request recognizes that the bandwidth reservation has been made to the MS01, starts monitoring the bandwidth (step 10), and returns a response to the QoS reservation + notification request (step 11). 12).

  On the other hand, the source terminal 2 and the media server are connected by a predetermined procedure using SIP (step a to step f), and guidance is sent to the terminal 2 (step 13).

  In FIG. 17, the wireless AP checks for available bandwidth (step 14), and transmits a QoS availability notification, which is a message for notifying that the available bandwidth exceeds the requested bandwidth, to the access controller (step 14). 15). This notification includes a CallID for identifying the call. The access controller sends a QoS empty notification to the SIP server (step 16), and a QoS empty response is returned from the SIP server (steps 17 and 19).

  Next, the session between the terminal 2 and the media server is terminated by a predetermined SIP procedure (step 20), and connection processing from the terminal 2 to the terminal 1 is started (step 21). The subsequent processing (step 22 to step 39 in FIG. 18) is the same as the processing in step 2 to FIG. 7 in FIG.

  Next, with reference to FIG. 19 to FIG. 21, a connection operation in the case of performing an extension group simultaneous call as another operation example will be described. In this example, the SIP server holds an extension group table in which a representative number is associated with a set of child numbers. Further, it is assumed that terminals URI1, URI2, and URI3 of the extension group with URI0 as the representative number exist under the wireless AP.

  In FIG. 19, when the SIP server receives an INVITE including the representative number (URI0) as the destination from the terminal 4 (step 1), the SIP server refers to the extension group table and searches for the child numbers (URI1, URI2, URI 3) is extracted, and a QoS reservation request, each of which is a destination, is transmitted to the access controller (steps 2 to 4). The access controller extracts a wireless AP corresponding to each destination (step 5), and sends a QoS reservation request including the MSID, required bandwidth, and CallID to the wireless AP. In this example, all destinations are the same. Since it is under the control of the wireless AP, all QoS reservation requests are transmitted to one wireless AP (steps 6 to 8). Note that CallID is the same for all destinations.

  A plurality of terminals belonging to the representative are called by calling with the representative number, but only one terminal is connected to the caller. Accordingly, in step 9, the wireless AP reserves a band for one line in association with CallID.

  Thereafter, a response to each of Steps 6 to 8 (Step 10) and a response to each of Steps 2 to 4 are returned (Step 11).

  Thereafter, the SIP server transmits INVITE to each terminal belonging to the extension group and rings each terminal (steps 12 to 14 in FIG. 20). In the example of FIG. 20, the terminal 3 responds and the terminal 3 and the terminal 4 are connected (step 15 to step 18). After that, the bandwidth securing process in the wireless AP for the terminal 3 is performed in the same sequence as Step 13 to Step 19 in FIG. 7 (Step 19 to Step 25).

  On the other hand, as shown in FIG. 21, message transmission / reception for canceling the INVITE is performed in the terminal 1 (steps 26 to 29). Then, a QoS release request for the terminal 1 is sent from the SIP server to the access controller (step 30), and sent from the access controller to the wireless AP (step 31). The wireless AP deletes the entry of the terminal 1 (step 32), and a response to the request is returned (steps 33 and 34). The same processing as that of the terminal 1 is performed on the terminal 2 (steps 35 to 43).

  Next, with reference to FIGS. 22-25, the example of a connection operation in the case of performing a call park is demonstrated. Here, an example in which a hold operation is performed at the terminal 1 while the terminal 1 and the terminal 2 are in a call, guidance is sent from the media server to the terminal 2, and then the terminal 2 and the terminal 3 are connected. Show.

  In step 2 of FIG. 22, the park hold operation in the terminal 1 is performed. Thereby, the media server and the terminal 2 are connected according to a predetermined SIP procedure (step 3 to step 15), and guidance is transmitted (step 16 in FIG. 23). Thereafter, the connection is disconnected (steps 17 to 20), and the bandwidth reserved for the terminal 1 in the wireless AP is released (steps 21 to 30).

  On the other hand, after a predetermined procedure in SIP (steps 27 to 30), after the SIP server receives the INVITE from the terminal 3 in step 31 of FIG. 24, the same as in steps 2 to 10 of FIG. Call connection processing including bandwidth reservation and bandwidth reservation in the wireless AP for the terminal 3 is executed, and a call is performed between the terminal 3 and the terminal 2 (step 50 in FIG. 25).

Next, a connection operation example in the case of performing call waiting will be described with reference to FIGS.
In a state where the terminal 1 and the terminal 2 are connected (step 1 in FIG. 26), the terminal 3 transmits INVITE, which is a connection request to the terminal 1, to the SIP server (step 2). Then, a QoS reservation request is transmitted from the SIP server (step 3), and the access controller transmits a QoS reservation request for the terminal 1 to the corresponding wireless AP through the same processing as the bandwidth reservation described so far (steps 4, 5). ).

  In the wireless AP, a band for one line is already secured for the terminal 1, and a band for another line is reserved here (steps 6 to 8).

  When the terminal 1 can establish a session for two lines, as shown in FIG. 27, the terminal 1 holds the call with the terminal 2 and the connection between the terminal 1 and the terminal 3 is made (step 9 to step 9). 20). When terminal 1 can only establish a session for one line, after terminal 1 receives INVITE (step 9 in FIG. 28), terminal 2 is parked by the processing shown in steps 2 to 30 in FIGS. The terminal 1 and the terminal 3 are connected (steps 11 to 21 in FIG. 28).

(Outline of device configuration)
Next, main functions provided in the SIP server, access controller, wireless AP, and console to realize the above-described operation will be described. FIG. 29 is a diagram for explaining a functional outline example of the SIP server 40, the access controller 30, the wireless AP 10, and the console 50.

  In addition to the call control function 41 for performing call control based on SIP, the SIP server 40 uses the registration / deletion of the terminal to / from the SIP server (registrar) as a trigger to perform URI registration (validation) with the access controller. / Access controller that has a function to make a request for QoS reservation / reservation / release to the access controller by making a request of / deletion (invalidation) and triggering a SIP message (INVITE / BYE / response, etc.) An interface function 42 is provided.

  The access controller 30 performs processing corresponding to each of the requests received from the SIP server 40, and transmits an answer (OK / NG) to the SIP server. The SIP server interface function 31 and the upper limit resource set in the wireless AP A determination function 32 that performs congestion determination based on the above, an anti-wireless AP interface function 33 that performs processing corresponding to a terminal registration / deletion request received from a wireless AP, and (a) a terminal MAC address and SIP− according to input from the console It has a database interface 35 and a console interface function 34 for setting the URI pair, (b) the maximum resource amount of the wireless AP, etc. in the database 35. This example is an example in which the access controller manages the bandwidth of each wireless AP.

  Further, in addition to the wireless AP function 11 inherent to the wireless AP, the wireless AP 10 has an anti-access controller interface function 12 that makes a terminal registration / deletion request to the access controller 30 triggered by the connection / disconnection of the terminal to / from the wireless AP. Have.

  The console 50 has a user interface function 51 that receives an input from the operator and an anti-access controller interface function 52 that transmits setting information to the access controller.

  The SIP server and the access controller are realized by installing programs for realizing the above functions in a computer having a CPU, a storage device, a communication device, and the like.

  Next, terminal management data and wireless AP management data in the database 35 held by the access controller 30 will be described.

  FIG. 30 shows an example of terminal management data. In the example shown here, the terminal MAC address and the terminal SIP-URI are associated with each other and registered in advance in the database 35 of the access controller 30 as a fixed value. Based on the data transmitted and received by the sequence described with reference to FIG. 6 and the like, the terminal is managed by recording the wireless state, call state, CallID, and connection AP as needed.

  The “wireless state” in the data shown in FIG. 30 is data indicating the connection state between the terminal and the wireless AP. When the terminal and the wireless AP are in the connected state, “Link Up” is recorded and when the terminal is in the disconnected state "Link Down" is recorded. Further, the ID of the wireless AP when in the connected state is recorded in “connected AP”.

  “Call state” is data indicating the state of the call, and “Register” is recorded when registered without a call connection, and “Unregister” is recorded when registration is deleted. In addition, when a QoS reservation request is received from the SIP server and the QoS reservation response is returned to the SIP server, "QoS reservation is in progress" is recorded, and after the QoS reservation response is returned to the SIP server, the QoS reservation request is received. "QoS reserved" is recorded until the QoS is received, and "QoS is being secured" is recorded and the QoS is secured when QoS is secured from when the QoS securing request is received until the QoS securing response is returned to the SIP server. In the state where QoS is secured after the response is returned to the SIP server, “QoS secured” is recorded.

  “CallID” records data when the “SIP state” is QoS reservation / QoS reservation / QoS reservation / QoS reservation, and sets a CallID for each call (SIP session). This CallID is used for grouping calls at the time of simultaneous incoming calls and specifying a call for QoS empty Notify ().

  By referring to the data shown in FIG. 30, the access controller can determine which call consumes the resource of which wireless AP.

  FIG. 31 shows an example of wireless AP management data. The APID and the resource upper limit value are fixed value data registered in advance, and the resource amount in use is changed at any time.

  “APID” in FIG. 31 is a unique ID for each wireless AP, and is the same information registered in “connection AP” of the terminal management data. The “resource upper limit value” is a resource upper limit value that can be used in the wireless AP. The “resource usage amount” is a resource amount currently used in the wireless AP, and dynamically changes according to the number of calls of a terminal connected to the wireless AP. Based on the difference between this information and the “resource upper limit value”, the free resource amount can be determined, and it can be determined whether or not the wireless AP is congested.

  The wireless AP may hold wireless AP management data. When the wireless AP holds the wireless AP management data, the wireless AP performs congestion determination, and the congestion determination result is transmitted to the access controller. On the other hand, since the access controller holds this data, it is not necessary to provide functions such as congestion determination to the wireless AP. The same applies to other embodiments.

(Access controller detailed function configuration)
Next, a detailed functional configuration of the access controller 30 will be described with reference to FIG. The example shown in FIG. 32 is an example when the access controller 30 performs wireless AP resource management such as congestion determination. As shown in FIG. 32, the access controller 30 has a database 35, a SIP cooperation I / F 60, a resource management function 70, a data management function 80, a wireless AP management function 90, a terminal management function 100, and a wireless AP cooperation I / F 110. ing.

  Hereinafter, the function of each functional unit will be described in more detail.

  The SIP cooperation I / F 60 includes a SIP request reception unit 61, a SIP request return unit 62, and a SIP notification unit 63.

  The SIP request reception unit 61 includes a terminal registration request reception unit 64 and a resource request reception unit 65. The terminal registration request receiving unit 64 receives a terminal registration request from the registrar. Also, the terminal registration information is passed to the terminal registration unit (application layer) 101. The resource request receiving unit 65 receives a resource request from the SIP server 40 and requests a resource operation from the resource reservation / release unit 71 according to the resource request type (reservation / reservation + notification / reservation / release). When the resource request type is “reservation + notification”, the resource status change monitoring unit 72 is requested to monitor resources.

  The SIP request return unit 62 includes a terminal registration request return unit 66 and a resource request return unit 67. The terminal registration request return unit 66 returns the result of the request to the terminal registration request reception unit 64 to the registrar, and requests a resource request. The return unit 67 returns the request result to the resource request receiving unit 65 to the SIP server 40.

  The SIP notification unit 63 has a resource state change notification unit 68, and the resource state change notification unit 68 sends a QoS empty Notify () notification to the SIP server 40 in response to a request from the resource state change monitoring unit 72. Do.

  The resource management function 70 includes a resource reservation / release unit 71 and a resource state change monitoring unit 72. The resource reservation / release unit 71 requests a resource operation from the data update unit 81 according to the resource request type (reservation / reservation / release). In addition, congestion is determined according to the amount of free resources. For example, if the value obtained by subtracting the resource amount in use from the upper limit resource amount is equal to or less than the requested resource amount, it is determined that congestion is occurring. The resource state change monitoring unit 72 monitors the free resources of the wireless AP, and notifies the resource state change notification unit 68 of the free state when the wireless AP changes to the free state.

  The data management function 80 has a data update unit 81. The data update unit 81 reads / adds / updates / deletes data from the database 35. Also, mutual conversion between SIP-URI and terminal MAC address is performed. The wireless AP management function 90 has a wireless AP / resource registration unit 91. The wireless AP / resource registration unit 91 sets the wireless AP registration and the resource upper limit value for the wireless AP in the database 35 based on an instruction from the console 50.

  The terminal management function 100 includes a terminal registration unit (application layer) 101 and a terminal registration unit (data link layer) 102. The terminal registration unit (application layer) 101 receives the SIP-URI of the resource management target terminal from the terminal registration request reception unit 64 and requests the data update unit 81 to perform data registration. With this process, SIP-URI is validated in this system. The terminal registration unit (data link layer) 102 receives the MAC address of the resource management target terminal from the terminal MAC registration request reception unit 111 and requests the data update unit 81 to perform data registration. By this processing, the terminal MAC address is validated in this system.

  The wireless AP cooperation I / F 110 has a terminal MAC registration request receiving unit 111. The terminal MAC registration request accepting unit 111 accepts an event triggered by a terminal event (Association / Disassociation / Reassociation) that occurs in the wireless AP, and responds to the terminal registration unit (data link layer) 102 according to the type of the event. Request registration / deletion / re-registration of terminal MAC address.

  The functional configuration described above is merely an example. Any configuration may be used as long as the operation described in this embodiment can be realized. The same applies to the other embodiments.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the second embodiment, a method for solving the problem during handover will be described.

  In the first embodiment, call band reservation in the wireless AP is performed with the SIP sequence as a trigger, but since a call is not started / terminated at the time of handover, no SIP sequence is generated. Thus, in the second embodiment, the bandwidth of the destination wireless AP is secured, etc., triggered by a wireless link reconnection request (Reassociation).

  With reference to FIG. 33, an overall operation flow of the system in the present embodiment when a terminal 1 in communication with another terminal 2 via a certain wireless AP 10 moves under the control of another wireless AP 20 and performs handover. To do.

  If the terminal 1 moves under the control of another wireless AP 20 and the destination wireless AP 20 is not congested (No in step 1), the handover is completed (step 2). If the destination wireless AP 20 is congested (Yes in step 1), the wireless AP 20 disconnects the wireless link with the terminal 1 and prompts the terminal to connect to the adjacent wireless AP 25, and the terminal 1 A wireless link connection to is made (step 4). However, the wireless link disconnection / connection retry is performed up to a predetermined number of retries, and when the number of retries reaches a predetermined value (Yes in Step 3), the access controller determines that the handover has failed, and the call Call processing such as sending out guidance to the partner terminal is performed (step 5).

  In the present embodiment, the wireless AP adjacent to the congested wireless AP 20 is a wireless AP other than the wireless AP 20 whose radio wave reach is within a range in which communication quality can be maintained during VoIP communication, as viewed from a terminal existing under the wireless AP 20. In addition to the wireless AP, the wireless coverage area includes a wireless AP in which the radio wave coverage is within a range where communication quality can be maintained during VoIP communication by moving the terminal to some extent. The same applies to the third embodiment.

  Next, referring to FIG. 34, an outline of the operation of the system in the present embodiment will be described by taking as an example a case where call processing is immediately performed on the terminal 2 when the destination wireless AP 20 is in a congested state. . The basic system configuration is the same as the system configuration in the first embodiment. In FIG. 34, the wireless AP 10 and the wireless AP 20 are connected to the access controller 30, and the terminal 1 is subordinate to the wireless AP 10 from the wireless AP 10 subordinate. The case of moving is shown. In the example of FIG. 34, it is assumed that the destination wireless AP 20 is in a congestion state.

  First, it is assumed that the terminal 1 is in a call with the terminal 2 via the wireless AP 10 (step A). When the terminal 1 moves under the wireless AP 20, the terminal 1 transmits a reconnection request to the wireless AP 20 by the handover function (step B). In response to this request, the access controller 30 transmits a bandwidth release request for releasing the bandwidth allocated to the terminal 1 to the wireless AP 10, and the wireless AP 10 releases the bandwidth (step C).

  Further, the access controller 30 transmits a bandwidth securing request to the wireless AP 20, but in the state of FIG. 34, the wireless AP 20 is in a congested state and fails to secure the bandwidth (step D). Then, the access controller 30 transmits a handover failure notification to the SIP server 40 (step E), and the SIP server 40 performs call processing on the terminal 2 (step F).

  Details of the processing in the present embodiment will be described below with reference to FIGS. 35 to 48, the register is assumed to be included in the SIP server. Further, terminal management data held by the access controller is shown as a call state management table. In addition, as a premise of the operation, it is assumed that the specified retry value (upper limit value) and the reconnection request rejection time are registered from the maintenance terminal to the access controller. This registration may be performed for each terminal or may be set as a value common to all terminals. Moreover, you may set for every wireless AP.

  First, a case where the destination wireless AP 20 is not congested will be described with reference to FIGS.

  In FIG. 35, it is assumed that communication is performed between the terminal 1 and the terminal 2 by performing the sequence described in the first embodiment (step 1 in FIG. 6 to step 19 in FIG. 7 and the like). (Step 1). Here, the terminal 1 moves from the subordinate of the wireless AP 10 to the subordinate of the wireless AP 20 (step 2). The terminal 1 transmits a reconnection request (Reassociation) to the wireless AP 20 (step 3), and the wireless AP 20 acquires and registers the MAC address (MSID) of the terminal 1 (step 4). The wireless AP 20 transmits a terminal registration request including the wireless AP 20 ID (AP02) and the terminal 1 MAC address (MS01) to the access controller (step 5). The access controller updates the registration by storing the ID (AP02) of the wireless AP 20 received from the wireless AP 20 in association with the MAC address (MS01) of the terminal 1 in the storage device (step 6). Note that the current call state for the terminal 1 is “QoS secured”. Then, the access controller returns a terminal registration response to the wireless AP 20 (step 7).

  In the present embodiment, when the access controller receives a terminal registration request regarding a terminal that has “QoS secured”, the access controller 1 does not receive a trigger from the SIP server, and the terminal 1 A QoS release request is transmitted (steps 8 and 9). Receiving this request, the wireless AP 10 releases the bandwidth for the terminal 1 and transmits a QoS release response to the access controller (steps 10 and 11).

  Subsequently, the access controller transmits a QoS ensuring request including MS01 and the necessary bandwidth to the wireless AP 20 (step 12). Since the necessary bandwidth between the terminal 1 and the terminal 2 has already been determined, the QoS reservation sequence is not performed.

  In step 13, the bandwidth is secured for the terminal 1 in the wireless AP 20, and a QoS ensuring response is transmitted to the access controller (step 14). Thereafter, a call is performed between the terminal 1 and the terminal 2 via the wireless AP 20.

  The processing from step 16 shows call disconnection processing. In steps 16 to 19, the SIP server disconnects the call by performing normal SIP sequence processing. In step 20, the SIP server sends a QoS release request to the access controller. The access controller extracts the corresponding wireless AP 20 (step 21), and transmits a QoS release request to the wireless AP 20 (step 22). The wireless AP 20 releases the bandwidth reserved for the MS01 so far (step 23), returns a QoS release response to the access controller (step 24), and the access controller sets the “call state” for the terminal 1 to “none”. And a QoS release response is returned to the SIP server (step 25).

  Next, an example of an operation in the case where the first moving destination wireless AP 20 is congested and the handover succeeds by connecting to the adjacent wireless AP 25 will be described with reference to FIGS. 38 to 40.

  In steps 2 to 39 in FIG. 38, terminal registration for the wireless AP 20 is performed in the access controller in the same manner as in steps 2 to 11 in FIG. 35, and the bandwidth for the wireless AP 10 is released.

  In step 11 of FIG. 39, the access controller that has received the QoS release response sets the call state for the terminal 1 to “handover”. Then, the access controller transmits a QoS ensuring request to the wireless AP 20 (step 12). Here, the wireless AP 20 determines that the bandwidth that can be currently allocated has been almost allocated, and the necessary bandwidth included in the QoS ensuring request cannot be reserved (step 13). Then, the wireless AP 20 returns a QoS ensuring response indicating that it is congested to the access controller (step 14).

  The access controller counts the number of times the wireless AP is congested after the handover. That is, in step 15, “1” is counted. This “1” indicates that one retry failed. In this example, the first handover is performed and the connection to the destination wireless AP is also included in the “retry”, but the count may be started from the retry after the first handover fails. . Then, this numerical value is compared with a predetermined numerical value, and when this numerical value has reached a predetermined numerical value, the process proceeds to call processing described later. Such determination processing is performed in order to prevent a retry from continuing forever. In the case of FIG. 39, it is assumed that the predetermined numerical value is a numerical value larger than 1, and the first retry failure is made, so that the process shifts to the process for reconnection without shifting to the call process.

  In step 16, the access controller transmits a wireless link disconnection request including MS01 and reconnection request rejection time to the wireless AP 20. The wireless AP 20 sets a reconnection request refusal time for the terminal 1 (step 17 in FIG. 40). Thereby, even when the wireless AP 20 receives a connection request again from the terminal 1, the wireless AP 20 rejects the connection request within the reconnection request rejection time. That is, even if a connection request is received, the subsequent operation is not performed.

The wireless AP 20 that has received the wireless link disconnection request disconnects the wireless link by transmitting a wireless link disconnection instruction (Disassociation) to the terminal 1 (step 18). The terminal 1 disconnected from the wireless link transmits a connection request (Association) to the wireless AP 25 that is a wireless AP adjacent to the wireless AP 20. Depending on the specifications of the terminal 1, the connection to the wireless AP 20 may be attempted several times again, and if the connection fails, the connection to the adjacent wireless AP may be performed. However, during the reconnection request rejection time, the wireless AP 20 Will never send a device registration request again.
The wireless AP 25 acquires and registers the MAC address (MSID) of the terminal 1 (step 20). The wireless AP 25 transmits a terminal registration request including the ID of the wireless AP 25 (AP03) and the MAC address (MS01) of the terminal 1 to the access controller (step 21). The access controller updates the registration by storing the ID (AP03) of the wireless AP 25 received from the wireless AP 25 in the storage device in association with the MAC address (MS01) of the terminal 1 (step 22). Then, the access controller returns a terminal registration response to the wireless AP (step 23).

  In the present embodiment, when the access controller receives a terminal registration request regarding a terminal that is “in handover”, the access controller does not receive a trigger from the SIP server and transmits the MS01 to the wireless AP 25 that has transmitted the terminal registration request. And a QoS ensuring request including the necessary bandwidth (steps 24 and 25).

  In step 26, the wireless AP 25 secures a bandwidth for the terminal 1, and a QoS ensuring response is transmitted to the access controller (step 27). The access controller sets the “call state” for the terminal 1 to “QoS secured”, and then a call is made between the terminal 1 and the terminal 2 via the wireless AP 25. The call disconnection process is the same as the process described with reference to FIGS.

  Next, with reference to FIG. 41 to FIG. 42, an operation example 1 in the case where the terminal 1 fails in the handover and the call control is performed on the communication partner terminal will be described.

  It is assumed that the processing from step 2 in FIG. 38 to step 25 in FIG. 40 has been performed because the destination wireless AP 20 is congested.

  In step 25, the wireless AP 25 that has received the QoS ensuring request determines that the bandwidth that can be currently allocated has been almost allocated, and the necessary bandwidth included in the QoS ensuring request cannot be reserved (step 26 in FIG. 41). ). Then, the wireless AP 25 returns a QoS ensuring response indicating that it is congested to the access controller (step 27).

  In this operation example 1, it is assumed that the specified value of the number of retries is set to 2. In step 28 in FIG. 42, the access controller sets the retry count value to “2” and compares it with the specified value, and determines that the number of retries has reached the specified value. Change to "None".

Then, the access controller transmits to the SIP server a handover failure notification including URL1 that is the URL of the terminal 1 and "congestion" that is the reason for handover failure. In this operation example 1, the SIP server that has received the handover failure notification performs normal termination processing by the Bye (steps 30 to 33).
There are various variations in the operation of the SIP server after receiving the handover failure notification, and which operation to use among these variations can be preset in the SIP server.
Next, an operation example 2 of the SIP server after receiving the handover failure notification will be described with reference to FIGS. 43 and 44 show an example in which it is determined that the handover has failed when the wireless AP 20 is congested. The processing until the handover failure notification is transmitted to the SIP server is as described above.

  In the operation example 2, the transfer from the terminal 1 to another terminal is performed. In this operation example, as in the case shown in FIG. 13 in the first embodiment, a transfer destination table in which a transfer destination terminal corresponding to the terminal is recorded for each terminal is registered in the SIP server. To do. Further, it is assumed that the terminal 3 (URI 3) that is the transfer destination of the terminal 1 is a VoIP terminal connected to the network by wire.

After receiving the response to Bye from the terminal 1 (step 3 in FIG. 43), the SIP server refers to the transfer destination table and acquires the transfer destination URI 3 corresponding to the terminal 1 (URI 1) that is the destination (step 4). ). Then, the SIP server executes a SIP sequence for requesting the terminal 2 to change the connection to the terminal 3 (steps 5 to 8), and transmits a QoS reservation request designating the destination URI 3 to the access controller ( Step 9). The access controller searches for a wireless AP having the terminal 3 of URI 3 under control (step 10), but such a wireless AP does not exist in the database, and a QoS reservation response indicating that fact is returned to the SIP server (step 11). Thereafter, the SIP server performs call connection processing for normal transfer (steps 12 to 16 in FIG. 44), and voice communication is performed between the terminal 3 and the terminal 2 (step 17). When the call is disconnected in steps 18 to 21, the SIP server transmits a QoS release request to the access controller in step 22 (step 22), but the corresponding wireless AP is not found in the access controller (step 23). A QoS release response is transmitted to the SIP server (step 24).
Next, an operation example 3 of the SIP server after receiving the handover failure notification will be described with reference to FIG.
In operation example 3, a media server is provided. After the SIP server receives the response to Bye in step 3, the media server and the terminal 2 are connected (steps a to i), and the media server “connects because it is congested. After the guidance prompting the end of the message such as “cannot be done” is sent to the terminal 2 (step j), the call is disconnected by the end of the call from the terminal 2 (step k to step n).
Next, an operation example 4 of the SIP server after receiving the handover failure notification will be described with reference to FIGS.
In the operation example 4, a guidance for notifying the terminal 1 to wait until communication becomes possible is sent to the terminal 2, and when the congestion of the wireless AP 20 is resolved and the terminal 1 becomes communicable, the terminal 1 and the terminal 2 are connected. To do.

  In step 3, when the SIP server receives a response to Bye, the SIP server sends a QoS reservation + notification request including the outgoing / incoming URI, required bandwidth, and CallID to the access controller (step 4). The QoS reservation + notification request is a message for notifying the wireless AP of the bandwidth for which the QoS reservation is to be made, and requesting that notification be made when there is enough space to secure the bandwidth.

  In step 5, the access controller transmits a QoS reservation + notification request to the corresponding wireless AP 20. The wireless AP 20 that has received the QoS reservation + notification request recognizes that the bandwidth reservation has been made to the MS 01, starts monitoring the bandwidth (step 6), and returns a response to the QoS reservation + notification request (step 7). 8).

  On the other hand, the terminal 2 and the media server are connected by a predetermined procedure using SIP (steps a to i), and guidance for notifying the terminal 2 that the wireless AP 20 is in a standby state until the resources are available is played. (Step j).

  In FIG. 47, the wireless AP 20 checks for available bandwidth (step 9), and transmits a QoS available notification, which is a message for notifying that the available bandwidth exceeds the requested bandwidth, to the access controller (step 9). 10). This notification includes a CallID for identifying the call. The access controller sends a QoS empty notification to the SIP server (step 11), and a QoS empty response is returned from the SIP server (steps 12 to 14).

  Next, the SIP server transmits a SIP message for reconnection to the terminal 1 to the terminal 2 and executes a SIP sequence for switching connections (steps 15 to 19). Then, through the same procedure as in the case of the incoming call from the terminal 2 to the terminal 1 in the first embodiment (step 20 in FIG. 47 to step 36 in FIG. 48), the call between the terminal 1 and the terminal 2 is performed. Performed (step 37).

(About device configuration)
An outline of functions of the apparatus according to the second embodiment will be described with reference to FIG. The basic configuration of the apparatus in the second embodiment is the same as the apparatus configuration in the first embodiment. Hereinafter, main points different from the apparatus of the first embodiment will be described.

  The call control function 41 in the SIP server 40 also has a function of executing a call control process at the time of handover failure. The access controller 30 includes a radio link retry determination function 36 and a handover success / failure determination function 37 in addition to the functions described in the first embodiment. The radio link retry determination function 36 counts the number of radio link retry failures and determines whether or not a preset number has been reached. The handover success / failure determination function 37 determines whether or not the handover has succeeded when the terminal is handed over. Specifically, when it is determined by the radio link retry determination function 36 that the number of failed radio link retries has reached a preset number, it is determined that the handover has failed, and the SIP server 40 is notified accordingly. To do. Further, the determination function 32 in the present embodiment also has a function of performing wireless AP congestion determination when a terminal call connection request is made.

  FIG. 50 shows terminal management data in the present embodiment. In this embodiment, the call state includes “in handover”. At the time of handover, the access controller sets the call state to “in handover” in response to the release of the band in the wireless AP before the handover. Then, at the time of handover, the call state is changed from “being handed over” to “QoS secured” in response to securing the bandwidth in the wireless AP of the handover destination.

  Further, the terminal management data in the present embodiment includes the number of radio link retries (upper limit value) for each terminal and the actual number of radio link retries. When the actual number of radio link retries reaches the upper limit value, it is determined that the handover has failed.

  FIG. 51 shows wireless AP management data for managing reconnection request refusal time in the present embodiment. As shown in FIG. 51, for each wireless AP and each terminal, a reconnection request rejection time and a reconnection request rejection elapsed time that is actually a time elapsed after disconnecting the wireless link are recorded.

  FIG. 52 shows a detailed functional configuration diagram of the access controller in the present embodiment. Hereinafter, a different part from 1st Embodiment is demonstrated.

  The SIP request return unit 62 includes a handover failure notification unit 69 that notifies the SIP server that handover has failed. Further, in addition to the function of the first embodiment, the resource reservation / release unit 71 has a function of examining the resource of the wireless AP and determining whether it is in a congestion state at the time of terminal handover. Further, the resource management function 70 has a radio link retry determination unit 73 that determines whether or not the number of radio link retries of a certain terminal has reached a predetermined upper limit value.

  In addition to the function described in the first embodiment, the data update unit 81 has a function of setting the call state of the terminal to “in handover” after releasing the resources of the source wireless AP at the time of handover of the terminal. Yes. In addition, the wireless AP cooperation I / F 110 includes a wireless link disconnection request unit 112. The wireless link disconnection request unit 112 is configured to link a wireless link to a reconnection destination wireless AP in order to reconnect the terminal to another adjacent wireless AP when resources of the reconnection destination wireless AP cannot be secured at the time of handover. A disconnect request is transmitted.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. In the first embodiment, when there is an incoming call from another terminal to a terminal connected to a congested wireless AP, an example of performing call control such as sending guidance to the other terminal explained.

  Even if a certain wireless AP is congested, the adjacent wireless AP may not be congested. However, in the first embodiment, the adjacent wireless AP cannot be effectively used. Therefore, in this embodiment, an example in which communication is continued using a wireless AP adjacent to a congested wireless AP will be described.

  First, with reference to FIG. 53, an outline of the operation of the system when the terminal 1 connected to the congested wireless AP 10 receives an incoming call from the terminal 2 will be described.

  First, it is assumed that the terminal 1 is connected to the wireless AP 10 through a wireless link. When the terminal 2 transmits a connection request to the terminal 1 (step A), the SIP server 40 transmits a bandwidth reservation request to the access controller 30 (step B). The access controller 30 transmits a bandwidth reservation request to the wireless AP 10, but the bandwidth reservation fails because the wireless AP 10 is congested (step C). Then, the access controller 30 notifies the SIP server 40 that the terminal 1 is switching to the adjacent wireless AP (step D). Thereafter, the access controller 30 transmits a wireless link disconnection request for the terminal 1 to the wireless AP 10, and the wireless AP 10 disconnects the wireless link with the terminal 1 (step E).

  The terminal 1 that has disconnected the wireless link with the wireless AP 10 establishes a wireless link connection with the adjacent wireless AP 20 (step F). Then, the access controller 30 makes a bandwidth reservation for the wireless AP 20 in response to a terminal registration request from the wireless AP 20, and when the bandwidth reservation is successful (step G), notifies the SIP server 40 to that effect (step H). The server 40 resumes the call connection sequence, and the terminal 1 and the terminal 2 are connected (step I).

  Next, with reference to FIG. 54, an outline of the operation of the system when the terminal 1 connected to the congested wireless AP 10 transmits to the terminal 2 will be described.

  First, it is assumed that the terminal 1 is connected to the wireless AP 10 through a wireless link. When the terminal 1 transmits a connection request to the terminal 2 (step A), a bandwidth reservation request is transmitted (step B), but the wireless AP 10 is congested and fails in bandwidth reservation (step C). Further, the access controller 30 notifies the SIP server 40 that the terminal 1 is being switched to the adjacent wireless AP (step D).

  Then, the SIP server 40 sends a call connection cancellation notification to the terminal 1 (step E), and the access controller 30 transmits a wireless link disconnection request to the terminal 1 to the wireless AP 10. The wireless link with is disconnected (step F).

  The terminal 1 that has been disconnected from the wireless link establishes a wireless link connection with the adjacent wireless AP 20 (step G). Then, when the user performs an operation on the terminal 1, the terminal 1 transmits a connection request to the terminal 2 (step H). Bandwidth is secured (step I), and a call between the terminal 1 and the terminal is established (step J). In the above method, the call is once disconnected, but the function of the terminal 1 can continue the call without disconnecting the call.

  Hereinafter, the operation of the system in the present embodiment will be described in detail.

  In this embodiment, when the wireless AP is not congested, the operation when there is an incoming call from the terminal 2 to the terminal 1 is as shown in FIGS. 6 to 8 in the first embodiment.

  Further, when the wireless AP is not congested, the operation in the case where a transmission is made from the terminal 1 to the terminal 2 is as shown in FIGS. 9 to 11 in the first embodiment.

Operation of the system in the case where the terminal 1 connected to the wireless AP 10 receives an incoming call from the terminal 2 in an environment where there is a wireless AP 20 that is not congested adjacent to the wireless AP 10 that is congested. Will be described in detail with reference to FIG.
Steps 1 to 4 in FIG. 55 are the same as steps 1 to 4 in FIG. In Step 5 after the wireless AP 10 receives the QoS reservation request from the access controller, the wireless AP 10 has almost allotted the bandwidth that can be currently allocated, and cannot reserve the necessary bandwidth included in the QoS reservation request. judge. Then, the wireless AP 10 returns a QoS reservation response indicating that it is congested to the access controller (step 6). The access controller sets the call state of the terminal 1 in the call state management table to “switching to adjacent wireless AP”, and returns a QoS reservation response including information indicating that the terminal 1 is switching to the adjacent wireless AP to the SIP server. (Step 7).

  The access controller counts the number of times the wireless AP is congested after the terminal connects to the wireless AP. That is, in step 8, “1” is counted. This “1” indicates that one retry failed. In this example, the first connection is also included in “retry”, but the count may be started from a retry after the first connection failure. Then, this numerical value is compared with a predetermined numerical value, and when this numerical value has reached a predetermined numerical value, the process proceeds to call processing described later. Such determination processing is performed in order to prevent a retry from continuing forever. In the case of FIG. 55, it is assumed that the predetermined numerical value is a numerical value greater than 1, and the first retry failure is made, so the process proceeds to reconnection.

  In step 9 of FIG. 56, the access controller transmits a wireless link disconnection request (corresponding to an adjacent wireless AP movement instruction) including MS01 and reconnection request rejection time to the wireless AP 10. The wireless AP 10 sets a reconnection request rejection time for the terminal 1 (step 10). Thereby, when the wireless AP 10 receives a connection request from the terminal 1 again, the wireless AP 10 rejects the connection request within the reconnection request rejection time. That is, the connection operation is not performed even when a connection request is received.

  The wireless AP 10 that has received the wireless link disconnection request disconnects the wireless link by transmitting a wireless link disconnection instruction (Disassociation) to the terminal 1. The terminal 1 disconnected from the wireless link transmits a connection request (Association) to the wireless AP 20 which is an adjacent wireless AP (step 12). Depending on the specifications of the terminal 1, the connection to the wireless AP 10 may be retried, but even in that case, the terminal registration request is not transmitted again from the wireless AP 10 during the reconnection request rejection time.

  The wireless AP 20 registers MS01 that is the MSID of the terminal 1 (step 13). Then, the wireless AP 20 transmits a terminal registration request including the ID of the wireless AP 20 (AP02) and the MAC address (MS01) of the terminal 1 to the access controller (step 14). The access controller updates the MSID and APID by storing the wireless AP ID (AP02) received from the wireless AP 20 and the MAC address (MS01) of the terminal 1 in the storage device. (Step 15). Then, the access controller returns a terminal registration response to the wireless AP 20 (step 16). The access controller sets the call state for the terminal 1 to “none” (step 17).

  Thereafter, bandwidth reservation is performed for the wireless AP 20 (steps 18 to 21 in FIG. 57), and the same processing as in step 8 to FIG. 7 in FIG. 6 is performed, so that a call between the terminal 1 and the terminal 2 is performed. A connection is made.

  Next, the operation when the wireless AP 10 is congested and the adjacent wireless AP 20 is congested and the call is interrupted will be described with reference to FIG.

  The processing from the INVITE transmission from the terminal 2 to the terminal re-registration with respect to the wireless AP 20 and the access controller is the same as the processing shown in FIGS.

  In FIG. 58, the access controller transmits a QoS reservation request to the wireless AP 20 (step 18). Since the wireless AP 20 is congested, a QoS reservation response indicating that the wireless AP 20 is congested is returned to the access controller (steps 19 and 20). The access controller compares the current number of retries with the upper limit of the number of retries, determines that the current number of retries (= 2) has reached the predetermined number of retries (= 2), and has failed the retry Determine (step 21). Therefore, the access controller returns a QoS reservation response including information indicating that the SIP server is congested (step 22). The SIP server that has received the QoS reservation response transmits a message indicating “call suspension” to the terminal (step 23).

  Note that the SIP server that has received the QoS reservation response may perform the same call control as that of the first embodiment on the terminal 2.

  Next, FIG. 59 shows the operation of the system when the terminal 1 connected to the wireless AP 10 makes a call to the terminal 2 in an environment where there is a wireless AP 20 that is not congested adjacent to the wireless AP 10 that is congested. Reference will be made to FIG.

  Steps 1 to 4 in FIG. 59 are the same as steps 1 to 4 in FIG. In step 5 after the wireless AP 10 receives the QoS reservation request from the access controller, the wireless AP 10 is determined to be congested and cannot reserve the necessary bandwidth included in the QoS reservation request (step 5). Then, the wireless AP 10 returns a QoS reservation response indicating that it is congested to the access controller (step 6).

  The access controller sets the call state of the terminal 1 in the call state management table to “switching to adjacent wireless AP”, and returns a QoS reservation response including information indicating that the terminal 1 is switching to the adjacent wireless AP to the SIP server. (Step 7). The SIP server that has received the QoS reservation response transmits a message for interrupting the call to the terminal 1 (step 8). Further, the access controller transmits a wireless link disconnection request (corresponding to an adjacent wireless AP movement instruction) including MS01 and the reconnection request rejection time to the wireless AP 10 (step 10). The wireless AP 10 sets a reconnection request rejection time for the terminal 1 (step 11). Thereby, when the wireless AP 20 receives the connection request from the terminal 1 again, the wireless AP 20 rejects the connection request within the reconnection request rejection time. That is, the connection operation is not performed even when a connection request is received.

  The wireless AP 10 that has received the wireless link disconnection request disconnects the wireless link by transmitting a wireless link disconnection instruction (Disassociation) to the terminal 1 (step 12). The terminal 1 disconnected from the wireless link transmits a connection request (Association) to the wireless AP 20 which is an adjacent wireless AP (step 13).

  The wireless AP 20 registers MS01, which is the MSID of the terminal 1 (step 14). Then, the wireless AP 20 transmits a terminal registration request including the wireless AP ID (AP02) and the terminal 1 MAC address (MS01) to the access controller (step 15). The access controller updates the MSID and APID by storing the wireless AP ID (AP02) received from the wireless AP 20 and the MAC address (MS01) of the terminal 1 in the storage device. (Step 16). Then, the access controller returns a terminal registration response to the wireless AP (step 17). The access controller sets the call state for the terminal 1 to “none”.

  Then, when the user performs a re-operation on the terminal 1, an INVITE message is transmitted from the terminal 1 to the SIP server (step 19). Thereafter, with respect to the wireless AP 20, the same processing as in Step 19 of FIG. 9 to Step 19 of FIG. 10 is executed, and call connection between the terminal 1 and the terminal 2 is performed.

  In the above case, if the wireless AP 20 is also congested, the processing of Step 1 in FIG. 59 to Step 8 in FIG. 60 is executed for the wireless AP 20 and the connection of the terminal 1 is disconnected. Thereafter, step 12 of FIG. 60 is executed, and the subsequent processing is performed for the adjacent wireless AP. In the case of outgoing calls, the access controller that has received the QoS reservation response indicating congestion is counting the number of retries, and if it reaches the upper limit, the wireless link disconnection request (adjacent wireless AP movement) Instruction) may not be transmitted.

(About device configuration)
An overview of the functions of the apparatus according to the third embodiment will be described with reference to FIG. The basic configuration of the apparatus in the third embodiment is the same as the apparatus configuration in the first embodiment. Hereinafter, main points different from the apparatus of the first embodiment will be described.

  The access controller 30 has a call connection control function 38 and a terminal control function 39 in addition to the functions described in the first embodiment. The call connection control function 38 includes a function of returning a response message indicating “switching to adjacent wireless AP” as a response to the QoS reservation request from the SIP server when congestion of the wireless AP is detected. In addition, the terminal control function 39 counts the function of transmitting a wireless link disconnection request when wireless AP congestion is detected, and the number of wireless link retry failures, and determines whether or not a preset number has been reached. The handover success / failure determination function 37 determines whether or not the handover has succeeded when the terminal is handed over.

  FIG. 62 shows terminal management data in the present embodiment. In the present embodiment, the call state includes “switching to adjacent wireless AP”. The access controller sets the call state to “switching to adjacent wireless AP” in response to detecting that the wireless AP connected to the terminal is congested. However, if the number of retries has reached the upper limit value, the switching operation is not performed, and therefore no call state is set. Then, when the terminal registration for the adjacent wireless AP is completed, the call state is changed from “switching to the adjacent wireless AP” to “none”.

  Further, the terminal management data in the present embodiment includes the number of radio link retries (upper limit value) for each terminal and the actual number of radio link retries. When the actual number of wireless link retries reaches the upper limit value, it is determined that the call connection has failed.

  FIG. 63 shows wireless AP management data for managing reconnection request refusal time in the present embodiment. As shown in FIG. 63, the reconnection request rejection time and the reconnection request rejection elapsed time that is actually the time elapsed since the wireless link was disconnected are recorded for each wireless AP and each terminal.

  FIG. 64 shows a detailed functional configuration diagram of the access controller in the present embodiment. In the following, parts different from the first embodiment will be mainly described.

  The resource request return unit 67 in the SIP request return unit 62 includes a function of notifying the SIP server that “switching to an adjacent wireless AP” is in progress when the wireless AP is congested. Further, the resource reservation / release unit 71 has a function of examining the resource of the wireless AP, determining whether or not it is in a congested state, and requesting disconnection of the wireless link when it is in a clothing state. Further, the resource management function 70 has a radio link retry determination unit 73 that determines whether or not the number of radio link retries of a certain terminal has reached a predetermined upper limit value.

  Further, the data update unit 81 has a function of setting the call state of the terminal to “switching to adjacent wireless AP” when the wireless AP is congested. In addition, the wireless AP cooperation I / F 110 includes a wireless link disconnection request unit 112. The wireless link disconnection request unit 112 transmits a wireless link disconnection request to the wireless AP in order to reconnect the terminal to another adjacent wireless AP when the wireless AP is in a congested state.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

It is a figure which shows the structural example of the conventional radio | wireless IP telephone system. It is a figure which shows an example of the system in embodiment of this invention. It is a figure for demonstrating the operation | movement outline | summary of the system in the 1st Embodiment of this invention. In the 1st Embodiment of this invention, it is a sequence diagram for registering the terminal 1 to an access controller. In the 1st Embodiment of this invention, it is a sequence diagram for deleting the terminal 1 registered from the access controller. FIG. 7 is a sequence diagram when an incoming request is made from a terminal 2 to a terminal 1 under a wireless AP that is not congested in the first embodiment of the present invention. FIG. 7 is a sequence diagram when an incoming request is made from a terminal 2 to a terminal 1 under a wireless AP that is not congested in the first embodiment of the present invention. FIG. 7 is a sequence diagram when an incoming request is made from a terminal 2 to a terminal 1 under a wireless AP that is not congested in the first embodiment of the present invention. FIG. 5 is a sequence diagram when a terminal 1 under a wireless AP that is not in a congested state transmits to a terminal 2 in the first embodiment of the present invention. FIG. 5 is a sequence diagram when a terminal 1 under a wireless AP that is not in a congested state transmits to a terminal 2 in the first embodiment of the present invention. FIG. 5 is a sequence diagram when a terminal 1 under a wireless AP that is not in a congested state transmits to a terminal 2 in the first embodiment of the present invention. FIG. 5 is a sequence diagram illustrating an operation example 1 when a terminal 2 receives an incoming request to a terminal 1 under a congested wireless AP in the first exemplary embodiment of the present invention. FIG. 10 is a sequence diagram showing an operation example 2 when a terminal 2 receives an incoming request to the terminal 1 under the congested wireless AP in the first exemplary embodiment of the present invention. FIG. 10 is a sequence diagram showing an operation example 2 when a terminal 2 receives an incoming request to the terminal 1 under the congested wireless AP in the first exemplary embodiment of the present invention. FIG. 10 is a sequence diagram illustrating an operation example 3 in a case where there is an incoming call request from the terminal 2 to the terminal 1 under the congested wireless AP in the first exemplary embodiment of the present invention. FIG. 10 is a sequence diagram showing an operation example 4 when a terminal 2 receives an incoming request to the terminal 1 under the congested wireless AP in the first exemplary embodiment of the present invention. FIG. 10 is a sequence diagram showing an operation example 4 when a terminal 2 receives an incoming request to the terminal 1 under the congested wireless AP in the first exemplary embodiment of the present invention. FIG. 10 is a sequence diagram showing an operation example 4 when a terminal 2 receives an incoming request to the terminal 1 under the congested wireless AP in the first exemplary embodiment of the present invention. In the 1st Embodiment of this invention, it is a sequence diagram which shows the connection operation | movement in the case of performing an extension group simultaneous call. In the 1st Embodiment of this invention, it is a sequence diagram which shows the connection operation | movement in the case of performing an extension group simultaneous call. In the 1st Embodiment of this invention, it is a sequence diagram which shows the connection operation | movement in the case of performing an extension group simultaneous call. FIG. 5 is a sequence diagram showing a connection operation when performing a call park in the first embodiment of the present invention. FIG. 5 is a sequence diagram showing a connection operation when performing a call park in the first embodiment of the present invention. FIG. 5 is a sequence diagram showing a connection operation when performing a call park in the first embodiment of the present invention. FIG. 5 is a sequence diagram showing a connection operation when performing a call park in the first embodiment of the present invention. FIG. 6 is a sequence diagram showing a connection operation when call waiting is performed in the first embodiment of the present invention. FIG. 6 is a sequence diagram showing a connection operation when call waiting is performed in the first embodiment of the present invention. FIG. 6 is a sequence diagram showing a connection operation when call waiting is performed in the first embodiment of the present invention. In the 1st Embodiment of this invention, it is a figure for demonstrating the function outline | summary of an apparatus. In the 1st Embodiment of this invention, it is a figure which shows the example of terminal management data. In the 1st Embodiment of this invention, it is a figure which shows the example of wireless AP management data. FIG. 3 is a detailed functional configuration diagram of an access controller 30 in the first embodiment of the present invention. It is a whole operation | movement flow of the system in the 2nd Embodiment of this invention. It is a figure for demonstrating the outline | summary of operation | movement of the system in the 2nd Embodiment of this invention. In the 2nd Embodiment of this invention, it is a sequence diagram which shows operation | movement when the movement-destination wireless AP 20 is not congested. In the 2nd Embodiment of this invention, it is a sequence diagram which shows operation | movement when the movement-destination wireless AP 20 is not congested. In the 2nd Embodiment of this invention, it is a sequence diagram which shows operation | movement when the movement-destination wireless AP 20 is not congested. FIG. 10 is a sequence diagram illustrating an operation example when the first destination wireless AP 20 is congested in the second embodiment of the present invention, but the handover succeeds by connecting to the adjacent wireless AP 25. FIG. 10 is a sequence diagram illustrating an operation example when the first destination wireless AP 20 is congested in the second embodiment of the present invention, but the handover succeeds by connecting to the adjacent wireless AP 25. FIG. 10 is a sequence diagram illustrating an operation example when the first destination wireless AP 20 is congested in the second embodiment of the present invention, but the handover succeeds by connecting to the adjacent wireless AP 25. FIG. 10 is a sequence diagram showing an operation example 1 when handover fails and call control is performed on a communication partner terminal in the second embodiment of the present invention. FIG. 10 is a sequence diagram showing an operation example 1 when handover fails and call control is performed on a communication partner terminal in the second embodiment of the present invention. In the 2nd Embodiment of this invention, it is a sequence diagram which shows the operation example 2 when a handover fails. In the 2nd Embodiment of this invention, it is a sequence diagram which shows the operation example 2 when a handover fails. In the 2nd Embodiment of this invention, it is a sequence diagram which shows the operation example 3 when a handover fails. In the 2nd Embodiment of this invention, it is a sequence diagram which shows the operation example 4 when a handover fails. In the 2nd Embodiment of this invention, it is a sequence diagram which shows the operation example 4 when a handover fails. In the 2nd Embodiment of this invention, it is a sequence diagram which shows the operation example 4 when a handover fails. In the 2nd Embodiment of this invention, it is a figure for demonstrating the function outline | summary of an apparatus. In the 2nd Embodiment of this invention, it is a figure which shows the example of terminal management data. In the 2nd Embodiment of this invention, it is a figure which shows the example of the radio | wireless AP management data for reconnection request refusal time management. FIG. 5 is a detailed functional configuration diagram of an access controller 30 in the second embodiment of the present invention. In the 3rd Embodiment of this invention, it is a figure for demonstrating the operation | movement outline | summary of a system when the terminal 1 connected to the wireless AP in congestion receives the incoming call from the terminal 2. In the 3rd Embodiment of this invention, it is a figure for demonstrating the operation | movement outline | summary of a system when the terminal 1 connected to the wireless AP 10 in congestion transmits to the terminal 2. FIG. In the third embodiment of the present invention, the operation of the system when an incoming call is received from the terminal 2 to the terminal 1 connected to the congested wireless AP 10 in an environment where the non-congested wireless AP 20 exists is shown. It is a sequence diagram. In the third embodiment of the present invention, the operation of the system when an incoming call is received from the terminal 2 to the terminal 1 connected to the congested wireless AP 10 in an environment where the non-congested wireless AP 20 exists is shown. It is a sequence diagram. In the third embodiment of the present invention, the operation of the system when an incoming call is received from the terminal 2 to the terminal 1 connected to the congested wireless AP 10 in an environment where the non-congested wireless AP 20 exists is shown. It is a sequence diagram. FIG. 10 is a sequence diagram illustrating an operation when a wireless AP 10 is congested and an adjacent wireless AP 20 is congested and a call is interrupted in the third embodiment of the present invention. In the third embodiment of the present invention, when terminal 1 connected to wireless AP 10 makes a call to terminal 2 in an environment where wireless AP 20 that is not congested exists adjacent to wireless AP 10 that is congested It is a sequence diagram which shows operation | movement of this system. In the third embodiment of the present invention, when terminal 1 connected to wireless AP 10 makes a call to terminal 2 in an environment where wireless AP 20 that is not congested exists adjacent to wireless AP 10 that is congested It is a sequence diagram which shows operation | movement of this system. In the 3rd Embodiment of this invention, it is a figure for demonstrating the function outline | summary of an apparatus. In the 3rd Embodiment of this invention, it is a figure which shows the example of terminal management data. In the 3rd Embodiment of this invention, it is a figure which shows the example of the radio | wireless AP management data for reconnection request refusal time management. FIG. 6 is a detailed functional configuration diagram of an access controller 30 in the third embodiment of the present invention.

Explanation of symbols

1, 2 Terminal 10, 20, 25 Wireless AP
11 wireless AP function 12 to access controller interface function 30 access controller 31 to SIP server interface function 32 determination function 33 to wireless AP interface function 34 to console interface function 35 database 36 wireless link retry determination function 37 handover success / failure determination function 38 call connection control Function 39 Terminal control function 40 SIP server 41 Call control function 42 Access controller interface function 50 Console 51 User interface function 52 Access controller interface function 60 SIP cooperation I / F
70 Resource Management Function 80 Data Management Function 90 Wireless AP Management Function 100 Terminal Management Function 110 Wireless AP Cooperation I / F

Claims (5)

An access control apparatus in a wireless IP telephone system having a plurality of wireless APs and VoIP call control means,
Upon receiving a connection from a terminal to a wireless AP, a terminal registration request including lower layer identification information and wireless AP identification information, which is identification information of the terminal in the data link layer, is received from the wireless AP. Lower layer registration means for registering wireless AP identification information in the storage means in association with the lower layer identification information;
A terminal registration request including upper layer identification information that is identification information used in call control of the terminal and the lower layer identification information is received from the VoIP call control means, and the upper layer identification information corresponds to the lower layer identification information. And upper layer registration means for registering in the storage means,
In response to a resource reservation request from the VoIP call control means that has received a call connection request relating to an incoming call to the terminal or an outgoing call from the terminal, the storage means based on the upper layer identification information of the terminal included in the request The wireless AP that accommodates the terminal is detected to perform allocation control of communication resources for the terminal in the wireless AP, and status information indicating the status of the terminal is displayed as the lower layer identification information and the upper layer. Resource control means for storing in the storage means in association with identification information ,
Call connection between the terminal and the partner terminal is performed by the VoIP call control means, status information indicating that communication resources for the terminal have been secured is stored in the storage means, and the terminal is connected to the partner terminal. In the state of communication, when the terminal moves from the subordinate of the connected wireless AP to the subordinate of the destination wireless AP that is another wireless AP,
In response to a connection from the terminal to the destination wireless AP, the lower layer registration means sends a terminal registration request including lower layer identification information of the terminal and identification information of the destination wireless AP to the movement Received from the destination wireless AP, the identification information of the destination wireless AP is registered in the storage means in association with the lower layer identification information and the upper layer identification information,
The resource control means confirms that state information indicating that communication resources for the terminal have been secured is stored in the storage means, without receiving a request from the VoIP call control means, Release the communication resources allocated to the terminal in the wireless AP, further determine whether the destination wireless AP is in a congestion state, if the destination wireless AP is not in a congestion state, A communication resource for the terminal is secured in the destination wireless AP, and when the destination wireless AP is in a congestion state, a request for disconnecting a radio link with the terminal is made without securing a communication resource. An access control device that transmits to an AP.   The access control device retains the number of times communication resources for the terminal have failed to be secured because another wireless AP connected to the terminal that has disconnected the wireless link with the wireless AP is in a congested state. If the number of failed communication resource allocations does not reach the predetermined number, a wireless link disconnection request is transmitted to the wireless AP that has failed to secure communication resource, and communication resource allocation fails. The access control apparatus according to claim 1, wherein when the number of times reached the predetermined number, a handover failure notification is transmitted to the VoIP call control means. An access control apparatus in a wireless IP telephone system having a plurality of wireless APs and VoIP call control means,
Upon receiving a connection from a terminal to a wireless AP, a terminal registration request including lower layer identification information and wireless AP identification information, which is identification information of the terminal in the data link layer, is received from the wireless AP. Lower layer registration means for registering wireless AP identification information in the storage means in association with the lower layer identification information;
A terminal registration request including upper layer identification information that is identification information used in call control of the terminal and the lower layer identification information is received from the VoIP call control means, and the upper layer identification information corresponds to the lower layer identification information. And upper layer registration means for registering in the storage means,
A resource reservation request for the terminal is received from the VoIP call control means that has received a call connection request related to an incoming call to the terminal or an outgoing call from the terminal, and based on the upper layer identification information of the terminal included in the request Search the storage means to detect the wireless AP accommodating the terminal, perform communication resource allocation control for the terminal in the wireless AP, and display state information indicating the state of the terminal as the lower layer identification information and the Resource control means for storing in the storage means in association with higher layer identification information ,
Call connection between the terminal and the partner terminal is performed by the VoIP call control means, and when the terminal is in communication with the partner terminal, the terminal is connected to another wireless AP from the subordinate of the connected wireless AP. The resource control means releases communication resources allocated to the terminal in the wireless AP, and the terminal is in handover. State information indicating is stored in the storage means, and further determines whether or not the first destination wireless AP is in a congestion state,
When the first destination wireless AP is in a congested state, the access control device transmits a radio link disconnection request with the terminal to the first destination wireless AP and receives the radio link disconnection request. When the terminal that has received the radio link disconnection instruction from the first destination wireless AP has made a connection to the second destination wireless AP, the lower layer registration means performs the lower layer identification information of the terminal and the A terminal registration request including identification information of the second destination wireless AP is received from the second destination wireless AP, and the identification information of the second destination wireless AP is received as the lower layer identification information and the upper layer identification information. Register in association with the storage means,
The resource control means confirms that the status information indicating that the terminal is undergoing handover is stored in the storage means, so that the second request can be made without receiving a request from the VoIP call control means . access control device, characterized in that intends line communication resources reserved for said terminal to the destination radio AP. The access control device holds the number of times communication resources related to the terminal have failed to be secured because another wireless AP connected to the terminal that has disconnected the wireless link with the wireless AP is in a congested state. and compared with the predetermined number of times, when the number of failed secure communication resources has not reached the predetermined number, transmits a radio link disconnection request to the wireless AP has failed to secure the communication resource, fail to secure communication resources 4. The access control apparatus according to claim 3, wherein when the number of times reached the predetermined number, a handover failure notification is transmitted to the VoIP call control means. A wireless IP telephone system having VoIP call control means and the access control device according to claim 2 ,
The VoIP call control means includes
A transfer destination table that records identification information of a transfer destination terminal that is a transfer destination of a call connection request related to an incoming call to the terminal;
When the handover failure notification is received from the access control device , the identification information of the transfer destination terminal is acquired from the transfer destination table, and a call connection request is made to the transfer destination terminal using the identification information Means for transmitting
A wireless IP telephone system comprising:

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