JP2006108834A - Call control method and call controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regulate registration and connection individually and appropriately while taking account of the state of each AP. <P>SOLUTION: The call controller 12 receives a first parameter group including information for specifying an RTC client 16 and information of an access point (AP) 14 to which the RTC client belongs through a network 11. Furthermore, the call controller 12 receives a second parameter group including information about QoS in the RTC client and updates a state information table 30 storing the information about QoS for each AP 14 to which the RTC client 16 belongs in accordance with the second parameter group. Upon receiving a registration request or connection request by the RTC client, the call controller 12 specifies that RTC client and an AP to which the RTC client belongs based on the first parameter group, and determines whether registration or connection is possible or not by referring to the state information table and the information about QoS of the AP to which the RTC client belongs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a call control method, a call control device, and a call control program for realizing real-time communication (RTC).

  Real-time communication is represented by voice communication (VoIP: Voice over IP) in a wireless LAN. For example, in a wireless LAN environment, many RTC clients represented by VoIP terminals are connected to one access point (AP). If the AP further includes a data communication client, that is, a client that transmits / receives still image data or text data that is not connected by real-time communication, the RTC is configured according to the amount of traffic on the wireless LAN. Communication quality (for example, voice call quality) decreases. Data communication clients accessing the web or mail are less susceptible to large packet delays, fluctuations, and deterioration of communication quality due to packet loss. However, since the RTC client is directly related to the communication quality of the application, for example, the voice call quality, it is easily affected greatly.

In order to avoid this, a method of limiting the total number of registered RTC clients and the call volume in a call control device such as a SIP server can be considered. However, such a method has a problem that although the total call volume is not large, it cannot cope with a case where calls are concentrated on a specific AP.
JP-A-4-373325 JP-A-11-220477

  Patent Document 1 discloses a technique for performing optimum regulation adapted to traffic characteristics in a mobile communication system that controls calling and location registration according to communication traffic. In Patent Document 1, a mobile terminal monitors a call restriction and location registration restriction signal from a base station (corresponding to an AP), and the terminal itself cancels a call or a registration request at a certain rate by random number generation. The restriction value transmitted by the restriction signal from the base station is dynamically changed according to the traffic.

  However, in order to apply this method to, for example, an RTC client in a wireless LAN environment, it is necessary to incorporate a mechanism for transmitting and receiving a restriction signal into the AP. It is not easy to modify the configuration of a large number of APs on the network, which is not desirable in terms of cost. Or, considering the configuration in which the call control device issues a restriction signal, it is possible to monitor the entire traffic, but it is not possible to individually issue a restriction signal in consideration of the state of each AP. There is a problem.

  Patent Document 2 discloses a technique for maintaining call quality by effectively restricting outgoing calls when the traffic volume increases in a LAN private branch exchange network system. In this technique, a traffic volume is measured in a LAN private branch exchange, and when it is determined that call restriction is necessary, a “call restriction message” is broadcast to a LAN base station or a LAN telephone. As a result, the subsequent call restriction can be distributed and controlled for each base station.

  This method is also based on the measurement result of the traffic amount of the LAN private branch exchange network. Therefore, when this is applied to a wireless LAN environment, the total traffic volume is small, but when the traffic volume under a specific base station is concentrated and the QoS of the RTC client under the base station is lowered, There was a problem that it was not possible to cope.

  An object of the present invention is to provide a data communication method, a call control device, and a call control program capable of appropriately regulating registration and connection individually in consideration of the state of each AP.

An object of the present invention is a call control method for controlling a call of an RTC client in a network environment including a real-time communication client (RTC client) that performs real-time communication and a terminal relay device connected to the RTC client. In the call control device capable of data communication with the RTC client via the network and the terminal relay device,
Receiving a first parameter group including information identifying an RTC client and information of a terminal relay device to which the RTC client belongs via the network; and a second parameter group including information on QoS in the RTC client , A step of updating a state information table storing information on QoS for each terminal relay device to which the RTC client belongs, and a registration request or connection by the RTC client according to the second parameter group When receiving the request, the RTC client and the terminal relay device to which the RTC client belongs are specified based on the first parameter group, and the terminal relay device to which the RTC client belongs is referred to by referring to the state information table Q of By referring to the information about the S, is accomplished by a call control method characterized by comprising the steps of: determining whether the registration of whether or connection, the.

  According to the present invention, when there is a registration request from the RTC client or when there is a connection request, whether or not it is possible is determined according to the state of the terminal control device to which the RTC client belongs. As a result, it is possible to control the quality of the RTC with higher granularity. Even when RTC clients and non-RTC clients coexist, registration / connection according to the traffic status of the actual RTC client is performed in order to determine whether registration or connection is possible based on the information about the QoS of the RTC client. Limits can be realized.

  Note that the terminal relay device includes an access point (AP) and an edge router in a wireless LAN environment.

  In a preferred embodiment, the state information table includes, as items, the number of RTC client registrations for each terminal relay device, and the step of determining whether or not registration is possible belongs to the RTC client in the state information table. Including the step of referring to the number of registrations related to the terminal relay device and determining whether or not the registration is possible, and if the registration is possible as a result of the determination of whether or not registration is possible, the RTC client in the status information table A step of updating the number of registrations relating to the terminal relay device to which.

  In another preferred embodiment, the state information table includes, as items, the number of connections of RTC clients for each terminal relay device, and the step of determining whether connection is possible or not is included in the state information table. A step of determining whether or not the connection is possible by referring to the number of connections related to the terminal relay device to which the device belongs, and if the connection is possible as a result of the determination of whether or not the connection is possible, A step of updating the number of connections related to the terminal relay device to which the RTC client belongs is provided.

  In a more preferred embodiment, the step of determining whether or not connection is possible refers to the step of determining whether or not connection is possible by referring to the number of connections related to the terminal relay device to which the RTC client to be connected belongs in the status information table. And when the connection is possible as a result of the determination as to whether or not the connection is possible, the state information table includes a step of updating the number of connections related to the terminal relay device to which the RTC client as the connection partner belongs. .

  According to this embodiment, whether or not connection is possible is determined according to the situation of the terminal relay device related to both the RTC client related to the connection request and the RTC client as the connection partner.

  When the RTC client and the terminal relay device can be connected wirelessly, the RTC client moves while connected to the network via another terminal relay device, so that the connection request from the RTC client is sent to the terminal relay device. It may be received by the relay device. As described above, when the RTC client is already connected, the registration and connection are permitted regardless of the number of registrations and / or the number of connections related to the terminal relay device related to the connection request in the status information table, and the information In the status table, it is desirable to update the number of registrations and the number of connections related to other terminal relay devices and the number of registrations and the number of connections related to terminal relay devices related to connection requests. Thereby, the RTC client can continue the RTC communication.

  In another preferred embodiment, the second parameter group includes a jitter value, a packet loss number and / or a round-trip delay time, which are fluctuations in the packet delay time in the RTC client, and updates the state information table. Updating a jitter value statistic, a packet loss count statistic, and / or a round trip delay time statistic.

  In yet another preferred embodiment, the step of updating the state information table includes updating a QoS value based on the statistical value of the jitter value, the statistical value of the number of packet losses, and / or the statistical value of the round trip delay time. And determining whether or not registration is possible or whether or not connection is possible includes referring to the QoS value. As this QoS value, an R value or a MOS value can be used.

  In a preferred embodiment, the step of determining whether or not registration is possible or whether or not connection is possible includes a step of comparing the referenced item with a threshold value in a connection restriction information table that stores a threshold value of each item. Including.

  In one embodiment, the RTC client includes a step of transmitting the first parameter group at the time of a registration request, and the call control device includes the first parameter group transmitted from the RTC client. Receive. Alternatively, the call control device may be configured to acquire the first parameter group based on information transmitted from an authentication server that authenticates the RTC client and a DHCP (Dynamic Host Configuration Protocol) server. good.

  In one embodiment, the call control device receives the first parameter group transmitted from a terminal relay device to which the RTC client belongs. Alternatively, the RTC client may include a step of transmitting the second parameter group, and the call control device may be configured to receive the second parameter group transmitted from the RTC client. Further, the call control device may be configured to obtain the second parameter group using SNMP (Simple Network Management Protocol) from the terminal relay device.

Another object of the present invention is to provide an RTC client via a network and the terminal relay device in a network environment including a real-time communication client (RTC client) that performs real-time communication and a terminal relay device connected to the RTC client. A call control device capable of data communication with
First receiving means for receiving a first parameter group including information for identifying an RTC client and information on a terminal relay device to which the RTC client belongs via the network, and information on QoS in the RTC client. A second reception unit that receives the second parameter group, and a state information table that stores information on QoS for each terminal relay device to which the RTC client belongs in accordance with the second parameter group by the second reception unit When a registration request or a connection request by the RTC client is received, the RTC client and the terminal relay device to which the RTC client belongs are specified based on the first parameter group, and Referring to the state information table, the R By referring to the information about QoS of C client belongs end station, it is also achieved by a call control apparatus characterized by comprising determination means for determining whether the registration of whether or connection, the.

  In a preferred embodiment, the status information table includes, as items, the number of RTC client registrations for each terminal relay device, and the determination means registers the terminal relay device to which the RTC client belongs in the status information table. In the state information table, when the state information processing unit is configured to determine whether the registration is possible with reference to the number, and the state information processing unit can register as a result of the judgment as to whether the registration is possible, The number of registrations related to the terminal relay device to which the RTC client belongs is updated.

  Further, in a preferred embodiment, the state information table includes, as items, the number of connections of RTC clients for each end relay device, and the determination means includes the end relay device to which the RTC client belongs in the state information table. The status information table is configured to determine whether or not the connection is possible with reference to the number of connections related to the status information, and when the status information processing unit can connect as a result of the judgment of the availability of the connection. The number of connections related to the terminal relay device to which the RTC client belongs is updated.

  In a further preferred embodiment, the determination means is updated so as to determine whether or not connection is possible by referring to the number of connections related to the terminal relay device to which the RTC client to be connected belongs in the status information table, and When the connection is possible as a result of the determination as to whether or not the connection is possible, the state information processing unit updates the number of connections related to the terminal relay device to which the RTC client as the connection partner belongs in the state information table. It is configured.

  In a preferred embodiment, the second parameter group includes a jitter value, a packet loss number and / or a round-trip delay time, which are fluctuations in packet delay time in the RTC client, and the state information processing means Configured to update value statistics, packet loss count statistics, and / or round trip delay time statistics.

  In a further preferred embodiment, the state information processing means is configured to update a QoS value based on the statistical value of the jitter value, the statistical value of the number of packet losses, and / or the statistical value of the round trip delay time, and The determination unit is configured to refer to the QoS value.

  In a preferred embodiment, the determining means is configured to compare the referenced item with a threshold value in a connection restriction information table storing each threshold value of the item.

  In this specification, the connection request includes a call request. In this case, the RTC client related to the connection request is the caller, and the RTC client that is the connection partner is the callee.

  According to the present invention, it is possible to provide a data communication method, a call control device, and a call control program that can appropriately regulate registration and connection in consideration of the state of each AP.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an entire wireless LAN communication environment according to an embodiment of the present invention. As shown in FIG. 1, a call control device 12 is connected to a network 11. For example, a router 15 is provided in the network. A plurality of access points (AP) 14-1, 14-2, 14-3,... Are also connected to the network 11. In the specification, it is expressed as AP14 except when referring to a specific AP. A router 15 is appropriately arranged on the network.

  A plurality of clients can be connected to the AP 14 via a wireless LAN. Here, for example, a terminal that performs voice communication by VoIP is referred to as an RTC client, and other terminals are referred to as non-RTC clients. In the present embodiment, the RTC client performs voice communication, but is not limited to this. Further, for example, a client that performs data communication or mail transmission / reception via the web corresponds to a non-RTC client. In the example of FIG. 1, for example, RTC clients 16-1 and 16-2 and a non-RTC client 17-1 are connected to AP1 (reference numeral 14-1). Hereinafter, the RTC client 16 and the non-RTC client 17 are referred to except when referring to a specific RTC client and a non-RTC client.

  RTC is a highly immediate data communication mainly using UDP (User Datagram Protocol), and is greatly affected by packet delay, delay fluctuation, loss, etc. due to fluctuations in network traffic. For example, it affects voice call quality). On the other hand, a non-RTC client that executes data communication via the web or data transmission / reception via e-mail mainly uses TCP (Transmission Control Protocol), and therefore the influence of the traffic load appears only as a response time fluctuation to the user.

  The call control device 12 mainly performs RTC client authentication, location management based on an IP address, and call control. Note that the call control device 12 does not need to be physically a single device, and may implement the above functions by transmitting and receiving data via a network. Procedures related to location registration / management and call control are described in SIP (Session Initiation Protocol: RFC3261) used in VoIP and H.264. H.323 is standardized as a representative.

  As shown in FIG. 1, most of the RTC client 16 and the non-RTC client 17 are connected to the network 11 in a mixed state under the jurisdiction of the AP 14 having jurisdiction over them. The RTC client 16 notifies the call control device 12 of its own IP address and ID (for example, a telephone number), and can receive a call by registering the current location (IP address). This registration process is periodically performed, and the registration information accumulated in the call control device 12 is refreshed. However, when re-registration from the RTC client 16 is not performed even though a predetermined time has elapsed, The call control device 12 deletes the registration information.

  Further, the RTC client 16 can move between the APs 14 and connects to APs in different subnets across the router (for example, from the area 18-2 managed by the AP-2 to the area 18 managed by the AP-3). In the case of moving to -3), the call control device 12 can re-register using the newly acquired IP address, thereby enabling seamless incoming calls.

  FIG. 2 is a block diagram showing the configuration of the call control device. As shown in FIG. 2, the call control device 12 includes a QoS information reception processing unit 20, a registration processing unit 22, an AP state information processing unit 24, a call control processing unit 26, and a database (DB) 28. . The DB 28 includes an AP state information table 30 and a connection restriction information table 32. FIG. 3 is a block diagram showing the configuration of the RTC client. As shown in FIG. 3, the RTC client 16 includes a QoS information transmission processing unit 40, a registration / call control processing unit 42, and a media transfer unit 44. The QoS information reception processing unit 20 of the call control device 12 and the QoS information transmission processing unit 40 of the RTC client 16 exchange data via the network. The call control processing unit 26 of the call control device 12 and the registration / call control processing unit 42 of the RTC client 16 exchange data via the network.

  The QoS information transmission processing unit 40 transmits QoS information (second parameter group) regarding the currently connected RTC to the QoS information transmission processing unit 20 of the call control device 12. This QoS information includes fluctuation of packet delay time (fluctuation of packet arrival interval: jitter value), number of packet losses, round trip delay time (RTT), and the like.

  For example, the QoS information transmission processing unit 40 can be implemented by using RTCP RR (Receiver Report) and SR (Sender Report) defined by RTP (RFC1889). Since the RTCP packet is originally transmitted only by the communication partner or by multicast, it is necessary to configure the call control device 12 to transmit the same packet. Since the IP address of the call control device 12 is preset in the RTC, it is not necessary to consider means for newly acquiring the address.

  The registration / call control processing unit 42 mainly executes a registration process and a signaling process for outgoing calls and incoming calls. In the registration process, an ID that can identify the currently connected AP, for example, a BSSID (MAC address), can be acquired and included in the registration message. Therefore, in the registration process, the following registration information (first parameter group) is transmitted.

(Client ID, AP_ID)
The client ID corresponds to a value that uniquely identifies the RTC client, and AP_ID corresponds to the BSSID. FIG. 5 is a diagram illustrating an example of a message transmitted by the registration / call control processing unit 42 of the RTC client. As shown in FIG. 5, the BSSID of the AP is included as “Call-Info” in the message.

  Signaling processing is performed using SIP (RFC3261) or H.264 mainly used in current VoIP. It can be implemented by following a procedure such as H.323.

  The media transfer unit 44 transmits / receives a media stream, and executes CODEC processing and packet transmission / reception processing for each medium.

  The QoS information reception processing unit 20 receives the QoS information (second parameter group) from the QoS information transmission processing unit 40 and notifies the AP state information processing unit 24 of the following data set.

(Client ID, jitter value, number of packet losses, round trip delay time (RTT))
The registration processing unit 22 executes registration processing and registration cancellation processing of the RTC client 16. The registration processing unit 22 creates and updates the AP state information table 30 and registers the RTC client 16 with reference to the AP state information table 30 and the connection restriction information table 32 in cooperation with the call control processing unit 26. Determine whether or not.

  FIG. 4A is a diagram illustrating a data configuration of the AP state information table. As shown in FIG. 4A, records (for example, reference numerals 401 and 402) of the AP state information table (reference numeral 400 in FIG. 4A) include AP_ID (ap_id) RTC registration number (cv_r), It includes the number of RTC connections (cv_c), QoS value (cv_qos), jitter statistical value (cv_jtr), loss statistical value (cv_loss), RTT statistical value (cv_rtt), and registered RTC list (cv_list). AP_ID indicates the ID of the access point. In the present embodiment, a record of the AP state information table is provided for each access point.

The number of RTC registrations indicates the number of RTC clients currently registered in the AP specified by AP_ID. The number of RTC connections indicates the number of RTC clients currently in real-time communication. The jitter statistics value is obtained by averaging the jitter values in the second parameter group from the RTC client registered in the AP for each AP specified by the AP_ID. Similarly, the loss statistical value and the RTT statistical value are obtained by averaging the number of packet losses and the round trip delay time, respectively. In this embodiment, the R value calculated based on the jitter statistical value, the loss statistical value, and the RTT statistical value is used as the QoS value. Of course, other values as the QoS value, for example, MOS (Mean
(Opinion Score) value may be used.

  The registered RTC list includes the client ID of the RTC client registered in the AP specified by the AP_ID.

  FIG. 4B is a diagram illustrating a data configuration of the connection restriction information table. As shown in FIG. 4B, records (for example, reference numerals 411 and 412) in the connection restriction information table (reference numeral 410 in FIG. 4B) include, as items, AP_ID (ap_id), RTC registration number limit value ( sv_r), RTC connection number limit value (sv_c), QoS value limit value (sv_qos), jitter statistic limit value (sv_jtr), loss statistic limit value (sv_loss), and RTT statistic limit value (sv_rtt) , The RTC registration number limit value, and the RTC connection number limit value respectively represent the upper limit of the number of RTC client registrations and the number of connections in the AP specified by the AP_ID. The QoS value limit value represents the lower limit of the QoS value. Further, the jitter statistical value limit value, the loss statistical value limit value, and the RTT statistical value represent upper limits of the jitter statistical value, the loss statistical value, and the RTT statistical value, respectively.

  The connection restriction information table 410 is determined in advance for each AP individually or uniformly for a plurality of APs, and stored in the DB 28. The AP state information table 30 is updated by the AP state information processing unit 24 in response to the AP state information processing unit 24 receiving the QoS information (second parameter group).

  The call control processing unit 26 processes a request regarding a call from the RTC client 16. When a registration message or a registration cancellation message is received from the RTC client 16, it is passed to the registration processing unit 22. The call control processing unit 26 determines the status of the AP to which the calling and called RTC clients belong by referring to the AP status information table 30 and the connection restriction information table 32 in cooperation with the registration processing unit 22. If the connection is possible, the connection between the calling RTC client and the called RTC client is permitted. This process will be described in detail later. The call control processing unit 26 executes other standard processes such as SIP / H323. The registration processing unit 22 can also execute other standard processes such as SIP / H323.

  Processing executed by the call control device 12 configured as described above will be described in detail below. FIG. 6 is a flowchart showing a registration process executed by the call control device 12 according to the present embodiment. As shown in FIG. 6, the call control processing unit 26 of the call control device 12 is initially in a standby state (step 600).

  When the call control processing unit 26 receives a message from the RTC client (step 601), the registration processing unit 22 that has received the notification indicating the reception indicates whether the message is a registration request or a registration cancellation. to decide. If there is no need for deregistration (No in step 602), that is, in the case of a registration request, the registration processing unit 22 stores the first parameter group and the registered location information table included in the received message. Referring to, it is determined whether or not the RTC client is connected (step 603). If NO in step 603, the registration processing unit 22 records the AP status information table and the connection restriction information table for the AP to which the RTC client belongs from the AP_ID in the first parameter group. Are identified, and the value in the record is referred to (step 604). Next, the registration processing unit 22 compares the RTC registration number and the RTC registration number limit value, the RTC connection number and the RTC connection number limit value, the QoS value and the QoS value limit value, respectively, and the RTC registration number is the RTC registration number limit value. If it is smaller (cv_r <sv_r), the number of RTC connections is smaller than the RTC connection number limit value (cv_c <sv_c), and the QoS value is larger than the QoS value limit value (cv_qos> sv_qos) (Yes in step 605) Yes)), it is determined that the RTC client can be registered. Therefore, the registration processing unit 26 instructs the AP state information processing unit 24 to update the AP state information table, and provides the AP state information processing unit 24 with the first parameter group as registration information.

  8 and 9 are flowcharts showing processing executed by the AP state information processing unit 24. The AP state information processing unit 24 is in a standby state until an instruction is received from the QoS information reception processing unit 20, the registration processing unit 22, and the call control processing unit 26 (step 801). When there is an instruction from any of the three types of processing units, the contents of the instruction are determined, and a predetermined process corresponding to the processing unit that issued the instruction is executed. In the case described above, the AP state information processing unit 24 receives the registration information (step 901 in FIG. 9), and determines whether or not the instruction is a deletion command (step 902). In the above case, since it is a registration instruction, it is determined NO in step 902. The AP state information processing unit 24 adds the client ID of the RTC client to be newly registered to the registered RTC list (cv_list) of the corresponding record in the AP state information table, and sets the number of RTC registrations of the record to “1”. Increase (step 606 in FIG. 6, step 903 in FIG. 9).

  In addition, the registration processing unit 26 creates a record including a client ID, an IP address, a registration time, and the like in a registration position information table (not shown) (step 607). Thereafter, the call control processing unit 26 returns a registration reception message to the RTC client 16 (step 608).

  On the other hand, if NO is determined in step 605, that is, the RTC registration number is equal to or greater than the RTC registration number limit value, the RTC connection number is equal to or greater than the RTC connection number limit value, or the QoS value is equal to or less than the QoS limit value. In any case, the call control processing unit 26 transmits a registration rejection message to the RTC client 16 (step 609). The RTC client 16 that has received this may transmit a voice message indicating that registration cannot be performed to the user, or may display a text message on the screen of the display device. Further, the registration rejection message may include information on neighboring APs (recommended connection destination APs) recommended for connection (for example, AP_ID of the AP).

  Next, the case where deregistration is necessary (Yes in step 603) will be described. In this case, the registration processing unit 22 passes the first parameter group to the AP state information processing unit 24 together with a registration cancellation instruction. Accordingly, the AP state information processing unit 24 determines Yes in step 902 of FIG. The AP state information processing unit 24 finds a record including the client ID of the RTC client corresponding to the registered RTC list (cv_list) from the AP state information table, and from the registered RTC list of the found record, While deleting the client ID, the value of the RTC registration number (cv_r) of the record is reduced by “1” (step 610, step 904 in FIG. 9). Further, the registration processing unit 22 deletes the record including the client ID from the registered position information table (step 611).

  Next, processing when the RTC client 16 is moved will be described. When an RTC connection (for example, a call) is not being made, the RTC client 16 changes from one AP (for example, AP-1 (reference numeral 14-1)) to a different AP (for example, AP-2 (reference numeral 14-2)). Consider moving to.

  In the present embodiment, the RTC client 16 performs registration by adding a new AP_ID using a connection with a new AP 14 as a trigger, and if successful, registers with the AP_ID of the source AP. To release. In this case, the call control device 12 receives the request simply as a continuous registration request and deregistration request, and basically follows the flowcharts shown in FIGS.

  Further, during the RTC communication (for example, telephone call), the RTC client 16 changes from a certain AP (for example, AP-1 (reference numeral 14-1)) to a different AP (for example, AP-2 (reference numeral 14-2)). If the destination AP (for example, AP-2) is congested, the number of registrations may exceed the registration number limit value.

  In the call control device 12, the RTC client 16 in communication is grasped. Therefore, in the case described above, the RTC client from the communicating RTC client may be handled with priority, and registration may be permitted even if the registration number limit value related to the destination AP is exceeded. More specifically, in the case described above, it is determined as Yes in step 603. Therefore, the registration processing unit 22 passes to the AP state information processing unit 24 an instruction for deregistration regarding the movement source AP and a registration instruction regarding the movement destination AP. In response to this, the AP state information processing unit 24 sets the number of RTC registrations (cv_r) and the number of RTC connections (cv_c) of the relevant AP in the AP state information table 30 to “1”, respectively. And the client ID of the RTC client is deleted from the registered RTC list (step 1101). In addition, the AP state information processing unit 24 increases the number of RTC registrations (cv_r) and the number of RTC connections (cv_c) of the record about the destination AP in the AP state information table 30 by “1”, respectively. At the same time, the client ID of the RTC client is added to the registered RTC list (step 1102). Thereafter, the process returns to step 607, and the registered position information table is updated (step 607).

  Next, processing when there is a call request or a disconnection request from the RTC client will be described with reference to FIG.

  When the call control processing unit 26 is waiting to receive a call request or a disconnection request (step 700) and receives a call request from a registered RTC client (step 701), the first parameter group and registered location information Referring to the table, it is determined whether or not the RTC client that has transmitted the call request is connected (step 702). If it is determined as No in step 702, the call control processing unit 26 specifies the AP_ID of the AP to which the calling and receiving RTC clients included in the call request belong, and AP status information Each record including the AP_ID is specified in the table (step 703). The call control processing unit 26 refers to the record for the AP to which the calling RTC client belongs in the AP status information table, and the RTC connection number is smaller than the RTC connection number limit value (cv_c <sv_c), and the QoS. It is determined whether or not the value is larger than the QoS limit value (cv_qos> sv_qos) (step 704). When it is determined as Yes in step 704, the call control processing unit 26 refers to the record of the AP state information table for the AP to which the called RTC client belongs, and the number of RTC connections is RTC. It is determined whether or not the connection number limit value is smaller (cv_c <sv_c) and the QoS value is larger than the QoS limit value (cv_qos> sv_qos) (step 705). If it is also determined as Yes in step 705, the call control processing unit 26 instructs the AP state information processing unit 24 to update the AP state information table, and as the call connection information, the call source and the call destination Pass the first set of parameters for both.

  Upon receiving the call connection information (step 802 in FIG. 8), the AP state information processing unit 24 determines whether it is a deletion command (step 803). In this case, since it is determined as No in step 803, the AP state information processing unit 24 stores the number of RTC connections (cv_c) in the AP state information table including the AP_IDs of the calling and called APs. ) Is increased by “1” (step 706, step 804 in FIG. 8).

  In addition, the registration processing unit 22 adds necessary information such as call destination information (for example, client ID of the callee RTC client) and call time to the record having each client ID in the registration position information table. Keep it. Thereafter, the call control processing unit 26 executes call connection processing based on the procedure such as SIP / H323 (step 707). In this manner, real-time communication between the calling RTC client and the called RTC client is started.

  For example, if it is determined NO in step 704 or NO in step 705, the call control processing unit 22 executes call rejection processing (step 708). For example, the call control processing unit 22 returns a message packet, voice, or IVR (Interactive Voice Response) indicating a busy state to the RTC client according to a procedure such as SIP / H323.

  Next, when receiving a disconnection request from the RTC client (step 709), the call control processing unit 26 instructs the AP state information processing unit 24 to update the AP state information table accompanying the disconnection request, and also includes necessary information. give. The AP state information processing unit 24 identifies records each including the AP_ID of the AP to which the calling and called RTC clients belong in the AP state information table, and sets the number of RTC connections (cv_c) of these records to “1”. ”(Step 710, step 805 in FIG. 8).

  In addition, the registration processing unit 22 adds necessary information such as a call disconnection time to the record of each client ID in the registration position information table. Thereafter, the call control processing unit 26 disconnects the call between the RTC clients according to a procedure such as SIP / H323 (step 711). Next, call processing when the RTC client 16 moves will be described. Since movement during RTC communication basically does not generate new call connection processing, call connection processing related to this (see FIG. 7) is not necessary. However, for example, in SIP, dynamic attribute change is possible such that QoS is lowered during communication and the voice codec is changed to a lower bandwidth. Even in this case, the call control device 12 can determine that it is a re-calling process (reInvite) from the connected RTC client 16. Therefore, in such a case, it is possible to process a message according to a normal standard procedure without using the call restriction procedure according to the present invention. When a recall request is received from the RTC client, the call control device 12 determines Yes in step 702 of FIG. In this case, the call connection process (step 707) is executed without passing through the processes of steps 703 to 706.

  Thus, according to the present embodiment, for each AP, the number of registered RTC clients belonging to the AP, the number of connections by real-time communication, the QoS value, and the like are held in the AP state information table, and the number of registrations, the number of connections, When the QoS value does not reach the predetermined limit value, the registration of the RTC client is permitted. In addition, for the APs to which the calling RTC client and the called RTC client respectively belong, if the number of connections of the RTC clients and the QoS value do not reach the above limit values, real-time communication between these RTC clients is permitted. . Thereby, call control with high granularity can be realized.

  Next, processing related to QoS information by the AP state information processing unit 24 will be described. As described above, the QoS information (second parameter group) is transmitted from the QoS information transmission processing unit 40 of the RTC client to the QoS information reception processing unit 20 of the call control device 12, and in the call control device 12, The AP state information processing unit 24 is notified of a data set of (client ID, jitter value, number of packet losses, round trip delay time (RTT)).

  When the AP state information processing unit 24 receives the data set as the QoS information (step 806), the AP state information processing unit 24 searches the AP state information table for a record having the AP_ID of the AP to which the RTC client belongs (step 807). Next, the AP state information processing unit 24 calculates the jitter statistical value, loss statistical value, and RTT statistical value in the record based on the jitter value, the number of packet losses, and the round trip delay time (RTT) in the received data set. Update. That is, a statistical value (for example, an average value) may be calculated again in consideration of a new jitter value, the number of packet losses, and a round trip delay time (RTT). In addition, the QoS value is calculated again with the change of these statistical values. The AP state information processing unit 24 stores the calculated QoS value, jitter statistical value, loss statistical value, and RTT statistical value in the record (step 808).

  The processing in steps 807 and 808 may be executed every time the data set is received, or the data set may be temporarily stored for a predetermined time and executed at an appropriate timing. You may comprise. Alternatively, the QoS information receiving unit 20 may temporarily hold a set of predetermined time data and notify the AP state information processing unit 24 of these at an appropriate timing.

  As described above, according to the present embodiment, optimal call control can be realized by appropriately changing the value relating to QoS in the AP state information table.

  Next, a second embodiment of the present invention will be described. In the first embodiment, registration information (first parameter group) is acquired from the RTC client. In the second embodiment, registration information is acquired from an authentication server or a DHCP (Dynamic Host Configuration Protocol) server.

  FIG. 10 is a block diagram showing the configuration of the call control device 112 according to the second embodiment. In FIG. 10, the same members as those in the first embodiment shown in FIG. As shown in FIG. 10, the call control device 112 includes the QoS information reception processing unit 20, the registration processing unit 22, the AP singing information processing unit 24, the call control processing unit 26, the DB 28, the authentication information acquisition unit 114, and the DHCP. An information acquisition unit 116 is included.

  The authentication information acquisition unit 114 performs data communication with an authentication server (not shown) via a network. The DHCP information acquisition unit 116 performs data communication with a DHCP server (not shown) via a network.

  In an authentication server (mainly a Radius server) used in IEEE 802.1X, the correspondence between the MAC address of the RTC client and the AP to which the RTC client belongs is known. Further, since the DHCP server knows the correspondence between the MAC address and the IP address of the RTC client, the call control device 112 acquires the information using the syslog or the like, so that the call control device 112 requests the registration of the RTC. Using the client's IP address as a key, the AP_ID to which the RTC client belongs can be associated. Even if DHCP is not used, it is sufficient that the call control device can refer to correspondence information between the IP address and the MAC address of the RTC client. When the RTC client is moved, in the second embodiment, the information described above is notified to the call control apparatus 112 from the authentication server and the DHCP server by using the syslog or the like. . Therefore, in the AP status information table 30, it is possible to update the record relating to the movement source AP and the movement destination AP and update the registered position information table.

  Next, a third embodiment of the present embodiment will be described. In the first embodiment, registration information is acquired from an RTC client, and in the second embodiment, registration information is acquired from an authentication server or a DHCP server. In the third embodiment, such information is acquired from the AP.

  In the AP, a MAC address and an IP address of a normally connected client are associated with each other. Therefore, when there is a registration request from the RTC client, the call control device may inquire about such information from the AP. Here, since it is inefficient to make an inquiry to all the APs, it is possible to configure the AP to report to the call control device using the syslog or the like. When the RTC client moves, in the third embodiment, the call control apparatus is notified from the AP by a syslog or the like along with the movement. Therefore, in the AP status information table 30, it is possible to update the record relating to the movement source AP and the movement destination AP and update the registered position information table.

  The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

  For example, in the above-described embodiment, the RTC client transmits QoS information (second parameter group) to the call control device. However, the present invention is not limited to such a configuration, and SNMP (Simple Network) is used. The management protocol may be configured to acquire QoS information from an AP or RTC client by using RTP-MIB (RFC 2959: Real-Time Transport Protocol Management Information Base) proposed by IETF.

  In the above embodiment, when the RTC client is registered, the AP status information table compares the number of RTC registrations, the number of RTC connections, and the QoS value with the limit values of the connection limit information table. However, the present invention is not limited to this, and only the RTC registration number and the QoS value may be considered.

  Further, the present invention can be applied not only in a wireless LAN environment but also in an environment where an RTC client is connected to an edge router by wire.

  Furthermore, in the above-described embodiment, the jitter value, the number of packet losses, and the round trip time (RTT) are used as the QoS information. However, the present invention is not limited to this, and any one or more of these are used. May be used, or other indicators may be used.

  In the embodiment, in order to determine whether registration is possible, the RTC registration number (cv_r) is compared with the RTC registration number limit value (sv_r), and the RTC connection number (cv_c) and the RTC connection number limit are compared. Although the value (sv_c) is compared (see step 605 in FIG. 6), the present invention is not limited to this. For example, the RTC registration number (cv_r) and the RTC registration number limit value (sv_r) are compared. You may do it.

FIG. 1 is a block diagram showing an entire wireless LAN communication environment according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the call control apparatus according to the present embodiment. FIG. 3 is a block diagram showing the configuration of the RTC client according to the present embodiment. 4A is a diagram illustrating a data configuration of the AP state information table, and FIG. 4B is a diagram illustrating a data configuration of the connection restriction information table 410. FIG. 5 is a diagram illustrating an example of a message transmitted by the registration / call control processing unit of the RTC client according to the present embodiment. FIG. 6 is a flowchart showing a registration process executed by the call control device according to the present embodiment. FIG. 7 is a flowchart showing processing executed by the call control device when there is a call request or disconnection request from the RTC client in this embodiment. FIG. 8 is a flowchart showing processing executed by the AP state information processing unit according to the present embodiment. FIG. 9 is a flowchart showing processing executed by the AP state information processing unit according to the present embodiment. FIG. 10 is a block diagram showing the configuration of the call control device according to the second exemplary embodiment of the present invention. FIG. 11 is a flowchart showing a registration process executed by the call control device according to this embodiment.

Explanation of symbols

11 Network 12 Call Control Device 14 AP
15 router 16 RTC client 20 QoS information reception processing unit 22 registration processing unit 24 AP state information processing unit 26 call control processing unit 28 DB
30 AP Status Information Table 32 Connection Restriction Information Table 40 QoS Transmission Processing Unit 42 Registration / Call Control Processing Unit 44 Media Transfer Unit

Claims (21)

A call control method for controlling a call of the RTC client in a network environment including a real-time communication client (RTC client) that performs real-time communication and a terminal relay device connected to the RTC client,
In a call control device capable of data communication with an RTC client via a network and the terminal relay device,
Receiving, via the network, a first parameter group including information identifying an RTC client and information of a terminal relay device to which the RTC client belongs;
Receiving a second set of parameters including information regarding QoS at the RTC client;
Updating a state information table storing information on QoS for each terminal relay device to which the RTC client belongs, according to the second parameter group;
When a registration request or a connection request is received by the RTC client, the RTC client and a terminal relay device to which the RTC client belongs are specified based on the first parameter group, and the status information table is referred to And a step of determining whether registration or connection is possible by referring to QoS information of the terminal relay device to which the RTC client belongs. The status information table includes, as items, the number of registered RTC clients for each terminal relay device,
The step of determining whether or not registration is possible includes the step of referring to the number of registrations related to the terminal relay device to which the RTC client belongs in the status information table and determining whether or not the registration is possible.
In addition, when registration is possible as a result of the determination as to whether or not registration is possible, there is provided a step of updating the number of registrations related to the terminal relay device to which the RTC client belongs in the status information table. The method according to 1. The status information table includes, as items, the number of connections of the RTC client for each terminal relay device,
The step of determining whether or not connection is possible includes the step of determining whether or not the connection is possible by referring to the number of connections related to the terminal relay device to which the RTC client belongs in the status information table,
The method further comprises a step of updating the number of connections related to a terminal relay device to which the RTC client belongs in the status information table when connection is possible as a result of the determination of whether connection is possible. The method according to 1 or 2. The step of determining whether or not connection is possible includes the step of determining whether or not connection is possible by referring to the number of connections related to the terminal relay device to which the RTC client as a connection partner belongs in the status information table,
Further, when connection is possible as a result of the determination as to whether or not connection is possible, there is provided a step of updating the number of connections related to the terminal relay device to which the RTC client as the connection partner belongs in the status information table. The method according to claim 3. The second parameter group includes a jitter value, a packet loss number, and / or a round-trip delay time, which are fluctuations in the packet delay time in the RTC client,
5. The step of updating the state information table includes a step of updating a statistical value of the jitter value, a statistical value of the number of packet losses, and / or a statistical value of a round trip delay time. The method according to any one of the above. Updating the state information table includes updating a QoS value based on the statistical value of the jitter value, the statistical value of the number of packet losses, and / or the statistical value of the round-trip delay time;
6. The method according to claim 5, wherein the step of determining whether registration is possible or connection is possible includes a step of referring to the QoS value. The step of determining whether or not registration or connection is possible includes a step of comparing a referenced item with a threshold value in a connection restriction information table storing a threshold value of each item. The method according to any one of 1 to 6. The RTC client comprises a step of transmitting the first parameter group upon registration request;
The method according to claim 1, wherein the call control device receives the first parameter group transmitted from the RTC client. 2. The first parameter group is configured in the call control device based on information acquired from an authentication server that authenticates the RTC client and a DHCP (Dynamic Host Configuration Protocol) server. The method described in 1. The method according to claim 1, wherein the call control device acquires the first parameter group from a terminal relay device to which the RTC client belongs. Transmitting the second parameter group in the RTC client;
The method according to claim 1, wherein the call control device receives the second parameter group transmitted from the RTC client. The method according to claim 1, wherein the second parameter group using SNMP (Simple Network Management Protocol) is acquired from the terminal relay device in the call control device. A call control method for controlling a call of the RTC client in a wired network environment including a real-time communication client (RTC client) that performs real-time communication and a wired terminal relay device connected to the RTC client by wire. ,
In the call control device capable of data communication with the RTC client via the network and the wired terminal relay device,
Receiving, via the network, a first parameter group including information identifying an RTC client and information of a wired terminal relay device to which the RTC client belongs;
Receiving a second set of parameters including information regarding QoS at the RTC client;
Updating a state information table storing information on QoS for each wired terminal relay device to which the RTC client belongs according to the second parameter group;
When a registration request or a connection request is received by the RTC client, the RTC client and a wired terminal relay device to which the RTC client belongs are specified based on the first parameter group, and the status information table is A call control method comprising: referring to information on QoS of the wired terminal relay device to which the RTC client belongs, and determining whether registration is possible or whether connection is possible. In a network environment including a real-time communication client (RTC client) for real-time communication and a terminal relay device connected to the RTC client, a call control device capable of data communication with the RTC client via the network and the terminal relay device Because
First receiving means for receiving, via the network, a first parameter group including information identifying an RTC client and information of a terminal relay device to which the RTC client belongs;
Second receiving means for receiving a second parameter group including information on QoS in the RTC client;
State information processing means for updating a state information table storing information on QoS for each terminal relay device to which the RTC client belongs, in accordance with a second parameter group by the second receiving means;
When a registration request or a connection request is received by the RTC client, the RTC client and a terminal relay device to which the RTC client belongs are specified based on the first parameter group, and the status information table is referred to A call control apparatus comprising: a determination unit configured to determine whether registration is possible or connection is possible by referring to information on QoS of a terminal relay apparatus to which the RTC client belongs. The status information table includes, as items, the number of registered RTC clients for each terminal relay device,
The determination means is configured to determine whether the registration is possible by referring to the number of registrations related to the terminal relay device to which the RTC client belongs in the status information table; and
The status information processing unit is configured to update the number of registrations related to the terminal relay device to which the RTC client belongs in the status information table when registration is possible as a result of the determination of whether or not registration is possible. The call control device according to claim 14. The status information table includes, as items, the number of connections of the RTC client for each terminal relay device,
The determination means is configured to determine whether or not the connection is possible by referring to the number of connections related to the terminal relay device to which the RTC client belongs in the status information table; and
The status information processing means is configured to update the number of connections related to the terminal relay device to which the RTC client belongs in the status information table when connection is possible as a result of the determination of the connection possibility. The call control device according to claim 14 or 15, characterized in that: The determination means is updated so as to determine whether or not connection is possible by referring to the number of connections related to the terminal relay device to which the RTC client to be connected belongs in the status information table, and
When the connection is possible as a result of the determination as to whether or not the connection is possible, the state information processing unit updates the number of connections related to the terminal relay device to which the RTC client as the connection partner belongs in the state information table. The call control device according to claim 16, wherein the call control device is configured. The second parameter group includes a jitter value, a packet loss number, and / or a round-trip delay time, which are fluctuations in the packet delay time in the RTC client,
18. The state information processing unit is configured to update the statistical value of the jitter value, the statistical value of the number of packet losses, and / or the statistical value of the round trip delay time. The call control device according to claim 1. The state information processing means is configured to update a QoS value based on the statistical value of the jitter value, the statistical value of the number of packet losses, and / or the statistical value of the round-trip delay time; and
19. The call control device according to claim 18, wherein the determination unit is configured to refer to the QoS value. 20. The determination unit according to claim 14, wherein the determination unit is configured to compare a referenced item with a threshold value in a connection restriction information table storing each threshold value of the item. The call control device according to Item. In a network environment including a real-time communication client (RTC client) that performs real-time communication and a wired terminal relay device that is connected to the RTC client by wire, the network and the RTC client via the wired terminal relay device A call control device capable of data communication,
First receiving means for receiving, via the network, a first parameter group including information identifying an RTC client and information of a wired terminal relay device to which the RTC client belongs;
Second receiving means for receiving a second parameter group including information on QoS in the RTC client;
State information processing means for updating a state information table storing information on QoS for each wired terminal relay device to which the RTC client belongs, in accordance with a second parameter group by the second receiving means;
When a registration request or a connection request is received by the RTC client, the RTC client and a wired terminal relay device to which the RTC client belongs are specified based on the first parameter group, and the status information table is A call control device comprising: a judgment means for judging whether registration is possible or connection is possible by referring to information related to QoS of a wired terminal relay device to which the RTC client belongs.

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