JP3995001B2 - VoIP system - Google Patents

Description

  The present invention relates to a VoIP (Voice over Internet Protocol) system using a wireless LAN, and more particularly to call management using a SIP server.

  A conventional wireless communication system using PHS (Personal Handy Phone) realizes a telephone call using a circuit switching method.

  For this reason, the number of simultaneous calls per PHS base station (wireless antenna) is determined. If there are a large number of PHS terminals that are talking with the maximum allowable number of PHS base stations, even if there are other PHS terminals in the service area of the PHS base station, the other PHS terminals will talk. However, there is a notification from the PHS base station that the call is in progress (BUSY), and the call cannot be made.

  Therefore, a PHS terminal that cannot make a call needs to access another PHS base station. However, even in the case of accessing other PHS base stations in this way, there is no particular effect on the PHS terminal during a call.

  On the other hand, a wireless call system using a wireless terminal (hereinafter referred to as an end point) using a wireless LAN realizes a call using a packet switching method. The maximum number of endpoints that can be connected per access point for a call using this packet switching method is theoretically determined to be 256. Therefore, in such an IP telephone system (VoIP system) using packet communication by wireless LAN, the maximum number of endpoints that can be connected per access point is 256.

  However, in order to operate an endpoint for a VoIP system in such a wireless LAN environment, a communication band of a certain level or more is always required for each endpoint for VoIP. Therefore, an endpoint for VoIP within a range satisfying this condition. Need to work.

The prior art document information related to the invention of this application includes the following.
JP 2003-284144 A

  In operation using a wireless LAN, communication cannot be ensured when a certain number of communication (calls) as endpoints is performed (hereinafter referred to as communication includes calls as well). Had trouble.

  That is, the wireless LAN is standardized by IEEE 802.11, and CSMA-CA (Carrier Sense Multiple Access with Collision Avoidance) is adopted as a communication method. In the wireless LAN, collision (collision of signals flowing on the same line) cannot be detected. Therefore, in this CSMA-CA, each endpoint continues for a certain time or more to confirm that the communication path is free, and then transmits data. I have to. For this reason, as the number of calls increases, the voice packet interval increases, leading to fluctuations in sound quality, interruptions, and the like.

  A communication failure that specifically occurs in such a manner greatly depends on the communication method and performance of the access point and the endpoint. Therefore, even if the number of endpoints connected per access point is less than the logical limit of 256, such communication failure occurs as the number of communication increases.

  When the communication of the VoIP endpoint is started beyond the number that can be normally communicated, not only the VoIP endpoint that has started communication last but also the VoIP endpoint that is already communicating.

  In order to avoid this communication failure, it is necessary to prevent only PHS terminals that are accessed later from being connected as in the above-described PHS system.

  Although it is possible to limit the number of connections per access point (the number of endpoints in the service area), keeping the number within the limit including the endpoints that are not calling does not directly limit the number of calls. Therefore, when there is a surplus in the number of calls, an excessive limit is imposed. Therefore, such a limitation on the number of connections leads to extremely poor use efficiency per access point and poor access point arrangement efficiency.

  For this reason, there is a problem that a mechanism (means) is required to keep the number of endpoints during communication within the limit.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a VoIP system using a wireless LAN that solves a communication problem due to congestion in a wireless section caused by an increase in the number of calls at one access point and improves operability.

The present invention was devised to achieve the above object, and the first invention records identification information of the wireless terminal in a VoIP system in which wireless terminals using a wireless LAN can communicate with each other. A SIP server for managing connection and call state of the wireless terminal based on the identification information, a wireless terminal for notifying the SIP server of the identification information, and an access point for connecting the wireless terminal via the wireless LAN And configured with
The identification information and the call state are recorded in a management table of the SIP server. The management table includes a column for recording the BSSID of the access point, a column for recording the IP address of the wireless terminal, and the wireless terminal. A field for recording the identifier of the SIP server, a field for recording a call state of the wireless terminal,
The SIP server is a VoIP system that checks and records the call state of the wireless terminal for each access point and limits the number of calls under the same access point.

  A second invention is a VoIP system in which the identification information is an identification ID of an access point used by the wireless terminal and individual identification information of the wireless terminal.

  The management table may include a column for recording the MAC address of the wireless terminal.

A third invention is a VoIP system for notifying the SIP server of the identification information when the wireless terminal is connected to the access point or when the connection is changed to another access point.

A fourth invention is a VoIP system in which the identification information is notified from the wireless terminal to the SIP server by a Register message to which a header field for notifying the BSSID of an access point is added.

  According to the present invention, it is possible to obtain a VoIP system using a wireless LAN, which solves a communication problem due to congestion in a wireless section caused by an increase in the number of calls at one access point and improves operability.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a system configuration diagram showing an example of a VoIP system according to the present invention.

  As shown in the figure, the VoIP system 1 includes an IP network 15 configured by connecting various servers, terminals represented by end points, and the like, an SIP server 11 connected to the IP network 15 and managing the terminals, A network connection device 12 connected to the network 15, access points AP1 and AP2 connected to the network connection device 12, and end points EP1 to EP3 connected to the access points AP1 and AP2 via a wireless LAN. Configured.

  The VoIP system 1 is a multimedia network system that transmits and receives voice information, data, and the like between end points EP1 to EP3 connected via a network connection device 12 and access points AP1 and AP2 via an IP network 15.

  The SIP server 11 controls the VoIP system 1 by SIP (Session Initiation Protocol) for establishing, maintaining, changing, deleting, and terminating a multimedia session of the connected IP network 15. It is a management server.

  The SIP server 11 manages the connection state and call (communication) state of the end points EP1 to EP3 connected to the access points AP1 and AP2.

  The SIP server 11 has an endpoint management table for managing the endpoints EP1 to EP3.

  The information recorded in the end point management table is the identification information issued by the end points EP1 to EP3 and the call state (call state) of the end points EP1 to EP3.

  The identification information issued by the end points EP1 to EP3 indicates a connection state indicating to which access points AP1 and AP2 the end points EP1 to EP3 are connected.

  The IP network 15 is a network that is controlled by IP (Internet Protocol) and transmits data and voice. An SIP server 11, a network connection device 12, and the like are connected to the IP network 15.

  The network connection device 12 is a device for connecting a terminal or the like to the IP network 15, and includes a switching hub, a router, a WAN cable, a LAN cable, etc. (not shown). The network connection device 12 is connected to various servers such as the SIP server 11 and terminals such as access points AP1 and AP2 and end points EP1 to EP3.

  The end points EP1 to EP3 are mobile terminals that are equipped with a wireless LAN function and can be connected to the access points AP1 and AP2 via a wireless LAN, and are IP telephone devices that implement a function of notifying the SIP server 11.

  That is, the end points EP1 to EP3 are connected to the access points AP1 and AP2 by a wireless LAN, and the end points EP1 to EP3 (or between the end points EP1 to EP3 and other terminals and end points not shown) are connected. It is a VoIP system call terminal capable of transmitting and receiving data and voice and capable of two-way calls.

  The end points EP1 to 3 notify the SIP server 11 of the start of the call when the end points EP1 to 3 or the other end points (not shown) are started. Further, the end points EP1 to 3 notify the SIP server 11 of the end of the call when the end points EP1 to 3 and the other end points (not shown) are ended.

  Next, the operation of the VoIP system 1 will be described.

  As illustrated, the end points EP1 to EP3 are connected by a wireless LAN via access points AP1 and AP2. The end points EP1 to EP3 connected by the wireless LAN transmit and receive data and voice to / from the end points EP1 to EP3 or other end points not shown via the access points AP1 and AP2.

  Here, the end points EP1 to EP3 are connected to one of the access points AP1 and AP2, and transmit and receive data and voice via the access points AP1 and AP2. However, the end points EP1 to EP3 are different from each other. When the wireless LAN connection of AP2 is established, the access points AP1 and AP2 transmit and receive data and voice via the network connection device 12. That is, each of the end points EP1 to EP3 is under one of the access points AP1 and AP2 and is managed by the SIP server 11.

  Here, the subordinates of the access points AP1 and AP2 or the access points AP1 and AP2 mean that the end points EP1 to EP3 are connected to any of the access points AP1 and AP2 via a wireless LAN.

  When the connection between the end points EP1 to EP3 and the access points AP1 and AP2 is established, the use of the line can be started. The end points EP1 to EP3 use the identification information of the end points EP1 to EP3 as the access points AP1 and AP2. The SIP server 11 is notified via the network connection device 12 and the IP network 15.

  The identification information notified to the SIP server 11 by the end points EP1 to EP3 is the BSSID (Basic Service Set Identifier) of the access points AP1 and AP2 used by the end points EP1 to EP3, that is, the MAC addresses of the access points AP1 and AP2. In addition, it is the individual identification information of the end points EP1 to EP3.

  The SIP server 11 that has received the notification of the identification information issued from the endpoints EP1 to EP3 records the received identification information in the endpoint management table that the SIP server 11 has.

  Specific identification information is an IP address and SIP-ID, which are individual identification information of the end points EP1 to EP3, and BSSIDs (MAC addresses) of the access points AP1 and AP2.

  The SIP server 11 creates an endpoint management table in the format shown in Table 1, for example, based on the notification information from each of the endpoints EP1 to EP3, and manages the connection status and call status of each endpoint EP1 to EP3. .

  Table 1 shows an endpoint management table in which identification information notified to the SIP server 11 by the endpoints EP1 to EP3 is recorded.

  The endpoint management table is composed of the following columns from the left.

  The column of AP ID (AP BSSID) indicates the BSSID (MAC address) of the access points AP1 and AP2 connected to each network connection device 12. Thereby, the SIP server 11 can recognize to which access points AP1 and AP2 the end points EP1 to EP3 are connected.

  The EP IP address column shows the IP addresses of the end points EP1 to EP3. The EP SIP-ID column indicates the identifier (ID) of the SIP server that each of the end points EP1 to EP3 has. The column of the call status of the endpoint indicates whether the endpoints EP1 to EP3 are busy or not. In FIGS. 2 and 3, the endpoint call status column in the endpoint management table is indicated by a circle when the call is in progress and by a cross when the call is not being made.

  The call state (call state) of the end points EP1 to EP3 is recognized and recorded by notifying the SIP server 11 of the start and end of the call of the end points EP1 to EP3, and the end state by the periodic management of the SIP server 11. You may carry out by grasping | ascertaining the call state of point EP1-3.

  The management table may be provided with an EP ID (EP MAC) column in addition to the above items. This EP ID indicates the MAC addresses of the end points EP1 to EP3 connected to the access points AP1 and AP2.

  In order to facilitate the management of the number of endpoint connections and the number of call states, the endpoint management table should be managed in a format sorted for each AP ID.

  An endpoint management table in the VoIP system 1 of FIG. 1 is shown at the bottom of the configuration diagram of the VoIP system 1.

  As can be seen from the figure, end points EP1 and EP2 are connected to the access point AP1 by a wireless LAN. This connection state is shown in the upper column of the endpoint management table. Looking at the endpoint management table from the left, it can be seen that the AP ID (AP BSSID) of the access point AP1 is AP1 in the AP ID (AP BSSID) column. In the right EP IP address column, the EP IP addresses of the end points EP1 and EP2 connected to the access point AP1 are recorded as IP1 and IP2, respectively. In the next EP SIP-ID column, the EP SIP-IDs of the end points EP1 and EP2 are recorded as S1 and S2.

  Similarly, looking at the lower column of the end point management table, it can be seen that the end point EP3 is connected to the access point AP2 by the wireless LAN. Looking at the endpoint management table from the left, the AP ID (AP BSSID) of the access point AP2 is AP2 in the AP ID (AP BSSID) column, and the access point AP2 is connected to the EP IP address column. The EP IP address of the end point EP3 is recorded as IP3, and the EP SIP-ID of the end point EP3 is recorded as S3 in the column of EP SIP-ID.

  As described above, the end points EP1 to EP3 notify the SIP server 11 of the identification information possessed by the end points EP1 to EP3 when the access points AP1 and AP2 start to use (Associate).

  In addition, when the access points AP1 and AP2 to be used are changed, the end points EP1 to 3 send new identification information to the SIP server 11, and the SIP server 11 receives the end points EP1 to EP3. The content recorded in the endpoint management table is changed according to the notification.

  As the information notification destination of the endpoints EP1 to EP3, a device that manages a call of a VoIP call as the SIP server 11 can be considered. It is also conceivable that the notification destination is not the SIP server 11 directly. In this case, identification information notified to each other may be exchanged between the notification destination system and the SIP server 11 that manages the call.

  The SIP server 11 can also grasp the degree of congestion of the calls of the end points EP1 to EP3 under the access points AP1 and AP2 by managing the call states of the end points EP1 to EP3.

  When a new call request is received from the VoIP end points EP1 to EP3, the access points AP1 and AP2 used by the end points EP1 to EP3 are referred to by referring to the recorded contents of the end point management table of the SIP server 11. The number of endpoints during the call is confirmed, and if the limit is exceeded, the call request is accepted (BUSY).

  FIG. 2 shows a part of the connection state of the network that cannot make a call due to call restriction despite a new call request from the end point, and the recorded contents of the end point management table of the SIP server 11 at that time.

  As shown in the figure, it is assumed that the end point EP5 is connected to the access point AP1 through a wireless LAN. The access point AP1 is connected to the SIP server 11 via the network connection device 12, the IP network 15 (see FIG. 1), and the like.

  Here, the allowable number of calls at the access point AP1 (call limit number) is within 3 calls, and the end points EP1, 2, 4 to 6 are already connected to the access point AP1, and among these end points EP1, 2, Assume that 4 is talking.

  Further, it is assumed that the allowable number of calls of the access point AP2 is within 3 calls, and the end point EP3 is already connected to the access point AP2, but no call is made.

  The SIP server 11 records this connection state and call state in the endpoint management table that the SIP server 11 has, which is shown in the lower part of FIG. The end point management table has the same item structure as that in Table 1, and the connection state of the end points EP1 to EP6 connected to the access points AP1 and AP2 and the call state of the end points EP1 to EP6 can be known.

  For example, the end point EP4 is connected to the access point AP1 by a wireless LAN. This connection state is shown in the upper column of the endpoint management table.

  Looking at the endpoint management table from the left, the AP ID (AP BSSID) of the access point AP1 is AP1 in the AP ID (AP BSSID) column, and the EP IP address of the endpoint EP4 is IP4 in the EP IP address column. In the EP SIP-ID column, the EP SIP-ID of the end point EP4 is recorded as S4. Looking at the call status column of the endpoint, it can be seen that the endpoint EP4 is busy (indicated by a circle). Similarly, it can be seen from the endpoint call status column in the endpoint management table that the endpoints EP1 and EP2 are talking.

  At this time, it is assumed that there is a call request (INVITE: session establishment request) from the end point EP5 connected to the access point AP1, as shown in FIG. The access point AP1 that has received the call request relays the call request issued from the end point EP5 to the SIP server 11.

  The SIP server 11 that has received a call request from the endpoint EP5 via the access point AP1 confirms the recorded contents of the endpoint management table it has. At this time, the end point management table (see FIG. 2) indicates that the end points EP1, 2, and 4 are already in a call as already described. Therefore, the new call request of the end point EP5 is a request for the fourth call from the access point AP1 and exceeds the call limit number, and the SIP server 11 needs to reject the call request of the end point EP5. is there.

  Based on the contents recorded in the endpoint management table, the SIP server 11 responds to the call request (inquiry) from the endpoint EP5 as busy (BUSY). Due to the operational limitation by the management of the SIP server 11 as described above, the end point EP5 which has made a call request cannot make a call.

  As already explained, the other access point AP2 is connected only to the end point EP3, and this end point EP3 is not talking, so there is still room for the allowable number of calls at the access point AP2. I know that there is.

  Therefore, the end point EP5 may change the connection to the access point AP2, which is another access point capable of sufficiently performing wireless LAN communication, according to an instruction from the SIP server 11 or a further request from the end point EP5.

  FIG. 3 shows a part of the network connection state in which the connection to the access point is changed after the operation restriction, and the recorded contents of the endpoint management table of the SIP server 11 at that time.

  The end point EP5 changes the connection by the wireless LAN from the access point AP1 to the access point AP2. This change in connection is notified from the endpoint EP5 to the SIP server 11 and recorded in the endpoint management table of the SIP server 11.

  The recorded contents of this endpoint management table are shown in the lower part of FIG. As can be seen from the content recorded at the bottom of the table, the end point EP5 is connected to the access point AP2 via a wireless LAN, and in the AP ID (AP BSSID) column, the AP ID (AP BSSID) of the access point AP2 is AP2, In the EP IP address column, the EP IP address of the end point EP5 is recorded as IP5b, and in the EP SIP-ID column, the EP SIP-ID of the end point EP5 is recorded as S5.

  In a state where the end point EP5 is connected to the access point AP2 by wireless LAN, the end points EP3 and EP5 are not in a call. This can be understood from the recorded contents in the endpoint call status column of the endpoint management table, and the endpoints EP3 and EP5 are recorded with a cross, meaning that no call is made. Therefore, the access point AP2 still has room for the call restriction number.

  As shown in the figure, it is assumed that there is a call request (INVITE) from the end point EP5 connected to the access point AP2. The call request is issued from the end point EP5 and transmitted to the SIP server 11 via the access point AP2.

  The SIP server 11 that has received a call request (inquiry) for the endpoint EP5 from the access point AP2 confirms the recorded contents of the endpoint management table it has. At this time, according to the recorded contents of the endpoint management table, as described above, the endpoints EP3 and EP5 are connected to the access point AP2, but the endpoint EP3 is not talking. Therefore, the new call request (INVITE) of the end point EP5 is within the call limit number of the access point AP2 (within 3 calls) as seen from the access point AP2, and the SIP server 11 permits the call request of the end point EP5. be able to.

  Based on the contents recorded in this endpoint management table, the SIP server 11 permits the call of the endpoint EP5 in response to a call request (inquiry) from the endpoint EP5, and the other party's telephone (other endpoint not shown) Make a ring (RING).

  When the other party's telephone responds to this ringing (RING) and the telephone conversation starts, the record in the endpoint call status column of the endpoint management table of the SIP server 11 changes from “X” to “O”, and the telephone call is completed. A circle indicating the inside is recorded.

  When the call with the other party's telephone at the end point EP5 is completed, the record in the call state column of the end point naturally changes from a circle mark to a cross mark.

  Further, the SIP server 11 not only makes a call request from the end points EP1 to 6 under the access points AP1 and AP2, but also from other end points (terminals) to the end points EP1 to EP6 under the access points AP1 and AP2. The number of calls is also limited for requests.

  FIG. 4 shows a case where there is a call request from the end point EP3 to the end point EP5 when the end points EP1 to EP6 and the access points AP1 and AP2 are in the call state shown in FIG.

  When a call request is transmitted from the end point EP3, the SIP server 11 first refers to the end point management table of the access point AP2 to which the end point EP3 is connected, and sets in advance the number of calls of the access point AP2. The number of calls restricted per access point AP2 (set to 3 in this case) is compared. In this case, since the number of calls at the access point AP2 is less than or equal to the call limit, the number of calls at the access point AP1 is further referred to by referring to the number of calls at the access point AP1 to which the endpoint EP5 to which a call is requested is connected. And the preset number of calls per access point AP1 (set to 3 in this case). As a result, since the number of calls exceeds the call limit at the access point AP1, a response (Busy) for rejecting the start of the call is transmitted from the SIP server 11 to EP3 in response to the call request from the end point EP3.

  As described above, the operation restriction management by the SIP server 11 does not deteriorate the congestion of the call of the access point AP1 that has already reached the call limit number, and the call failure of the other end points EP1 to EP6 due to the increase in the number of calls. Will not occur.

  Further, the end point EP5 whose call is restricted by the state of the access point AP1 changes the wireless LAN connection to another access point AP2 in response to an instruction from the SIP server 11 or a request from the end point EP5, and still has a spare access point. It is possible to receive a call permission from the SIP server 11 via the AP 2 and to talk to other terminals (end points EP1 to EP4, 6 or other terminals not shown).

  For this reason, the VoIP system 1 can sufficiently secure the communication band of the access point AP1, and can also ensure a sound call of the end point EP5.

  When the end point EP5 cannot switch the communication to the access point AP2, that is, when the SIP server 11 does not have the function of instructing the end point EP5 to switch to the access point AP2, or the end point EP5 is for some reason. There are cases where switching to the access point AP2 cannot be performed according to an instruction from the SIP server 11.

  In these cases, the call request of the endpoint EP5 is rejected by the BUSY notification from the SIP server 11 to the endpoint EP5. In this case, the end point EP5 makes a call when the person using (possessing) the end point EP5 actively moves under the access point AP2 and makes a call request to the SIP server 11. It becomes possible.

  Further, it is assumed that the end point EP5, which is able to make a call without any problem under the access point AP1, actively moves under the access point AP2 together with a human being used for some reason. In this case, it is assumed that the access point AP2 is already in a call state where the number of calls is full. At this time, the SIP server 11 that has received the notification that the end point EP5 has moved from the access point AP1 to the access point AP2 exceeds the call limit number of the access point AP2, even if the end point EP5 is busy. The call can be interrupted (BYE).

  Furthermore, by using the identification information notified to the SIP server 11 and notifying the other systems of these identification information, the SIP server 11 or the other system sends the individual identification information of each of the endpoints EP1 to EP6 to the endpoint EP1. Can be used as location information (i.e., which access points AP1 and AP2 are under control), and the information of the endpoints EP1 to EP6 can be used for purposes other than the VoIP system. It becomes.

  Next, a method for acquiring an AP ID by an endpoint will be described.

  As shown in FIG. 5, when establishing communication with the access point, the end point makes a detection request or a connection request to the access point according to the IEEE 802.11 connection procedure. In response to this request, the access point transmits a detection request response and a connection request response to the endpoint. The data from the access point, such as the detection request response and the connection request response, includes the BSSID (MAC address) of the access point, whereby the end point can acquire the BSSID of the access point.

  Next, a method for the endpoint to notify the BSSID of the access point will be described.

  In normal operation, the endpoint regularly transmits a Register message to the SIP server at the time of initial registration and after registration, and uses this to notify the BSSID. In addition, when the access point to which the end point is connected is switched, a Register message is immediately transmitted after switching, and the BSSID of the newly connected access point is notified.

  A specific BSSID notification method is described in the format of “802.11-BSSID: AP ID” by adding a header name “802.11-BSSID” to the Register message. The APSID part is set with the BSSID of the access point and transmitted. In addition to this, when notifying the MAC address of the endpoint together, information is added by the epmac parameter.

  That is, the Register message is composed of a text file and is composed of a plurality of header fields (for example, “To”, “From”, “Contact”, etc.), but in order to realize the notification function, a new header field called 802.11-BSSID is created. Add Further, when notifying the MAC address of the endpoint, an additional parameter used in a header field called epmac is added.

  As a specific example of the header field of the Register message to be added, there is a format of “802.11-BSSID: xx.xx.xx.xx.xx.xx; epmac = yy.yy.yy.yy.yy.yy”.

  In addition to the notification method using the Register message, a notification method can be added to the header of an INVITE message for starting a call, an INVITE message for updating a session, or a BYE message for disconnecting a call. It is.

  Next, a processing method when an access point ID notification is received from an end point will be described.

  In FIG. 6, the end point EP5 is connected to the access point AP1 and makes a connection request to the SIP server 11. Here, the Register message and the endpoint management table when the SIP server 11 also manages the MAC addresses of the endpoints EP1 to EP6 are shown. In the Register message, the BSSID of the access point AP1 is included in the header field 802.11-BSSID. The MAC address information of the end point EP5 is added to the epmac parameter.

  When the SIP server 11 receives a notification of the AP ID of the access point AP1 from the end point EP5, the SIP server 11 records information on the access point AP1 connected to the end point EP5 in association with the end point management table. If the processing of the received Register message is OK, the SIP server 11 transmits a 200 (OK) response to the endpoint EP5. This 200th response means that the processing of the Register message itself is OK, and the processing corresponding to the added header is naturally OK.

  If the recorded endpoint information is not updated within the validity period of the Register (specified by the value of the Expire parameter in the Contact header of the Register message), the registration is deleted.

  In the above description, the end points EP1 to EP6 notify the SIP server 11 of the identification information. Instead, the access points AP1, AP2, the upper network connection device 12, a LAN switch (not shown), etc. act on behalf of the SIP server 11. Even in the method of notifying the server 11 of the identification information, the same connection management and number of calls can be restricted by the SIP server 11.

  When the notification function to the SIP server 11 cannot be implemented in the terminal (endpoints EP1 to EP6), the access points AP1 and AP2 instead of the endpoints EP1 to EP6, and the endpoints EP1 to EP6 subordinate to the own access point AP1 and AP2 The number of calls can be limited by implementing a function for identifying and notifying information on the access points AP1 and AP2.

  As a method of notifying the SIP server 11, the access points AP1 and AP2 can notify using a NOTIFY message which is one form of SIP message. By adding an AP-ID or an EP parameter to the header field of the NOTIFY message, the access points AP1 and AP2 use the SIP server to identify the identification information of the endpoints EP1 to EP6 connected to their BSSID. 11 can be notified. Since a plurality of endpoints are normally connected to the access point, it is preferable to notify a plurality of endpoints simultaneously in the format EP = A, B, C... (A, B, C are MAC addresses of the endpoints).

  The access points AP1 and AP2 also transmit the endpoint list information to the SIP server even when the information of the connected endpoints changes.

  In addition to the SIP message, any message that can maintain consistency between the access point and the SIP server can be used as a notification to the SIP server.

  Similar to the case where the identification information is notified to the SIP server 11 by the access points AP1 and AP2, the network connection device 12 can also notify the SIP server 11 of the identification information. The network connection device 12 notifies the SIP server 11 of the AP ID (AP BSSID) of the access point connected to the port and the identification information of the end point connected to the access point.

  In addition, the network connection device 12 also stores the list information of the endpoints EP1 to EP6 in the SIP server 11 when the information of the endpoints EP1 to EP6 registered in the port to which the access points AP1 and AP2 are connected changes. Send.

  In any case, the access points AP1 and AP2 and the network connection device 12 have a function of decoding and interpreting a part of communication data with respect to the IP address, SIP-ID, etc. of the end points EP1 to EP6. Need to be.

  As described above, the VoIP system can maintain a healthy call by managing the end points connected to each access point and restricting calls after grasping the number of calls per access point. .

  In addition, when an endpoint that cannot make a call due to this call restriction makes a call request, the wireless LAN connection change to another access point that has not reached the call restriction number is made to secure the call of the endpoint that made the call request. be able to.

  The SIP server manages the connection state and call state of the endpoints of these VoIP systems, and the identification information of each endpoint for management is notified to the SIP server when connecting from each endpoint to the access point and when the connection is changed. The

  The SIP server records each notified identification information in the endpoint management table and can use it for the management of the VoIP system described above.

  As described above, the VoIP system of the present invention eliminates a call (communication) failure due to an increase in the number of calls for each access point, which has been a problem in the past, and secures a sufficient call bandwidth at each access point.

  The VoIP system secures a sufficient call bandwidth for each access point by changing the access point to which the connected end point is connected as necessary, and also makes a call request (or other) for each end point. In response to a call request from a terminal (end point) (not shown) of FIG.

  The present invention can be used when building a wireless VoIP system in an enterprise. Secondary, it can be applied to the location management system of each endpoint owner.

It is a block diagram which shows the outline | summary of an endpoint information notification function. It is the block diagram which shows the state of the network which is performing the operation restriction, and the recorded contents of the endpoint management table of the SIP server at that time. FIG. 6 is a block diagram showing a state of a network in which the connection of the endpoint is changed after the operation restriction, and a recorded content of the endpoint management table of the SIP server at that time. It is a block diagram which shows the state of the network which is performing the operation restriction. It is a figure which shows the acquisition method of AP ID by an endpoint. It is a figure explaining the processing method when the notification of AP BSSID is received from the endpoint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 VoIP (Voice over Internet Protocol) system 11 SIP (Session Initiation Protocol) server 12 Network connection apparatus AP1, AP2 Access point EP1-3 Endpoint (terminal)
15 IP (Internet Protocol) network

Claims (5)

In a VoIP system in which wireless terminals using a wireless LAN can communicate with each other, the identification information possessed by the wireless terminals is recorded, and the connection of the wireless terminals based on the identification information, and the SIP server for managing the communication state, A wireless terminal for notifying the SIP server of the identification information, and an access point for connecting the wireless terminal via the wireless LAN;
The identification information and the call state are recorded in a management table of the SIP server. The management table includes a column for recording the BSSID of the access point, a column for recording the IP address of the wireless terminal, and the wireless terminal. A field for recording the identifier of the SIP server, a field for recording a call state of the wireless terminal,
The VoIP system, wherein the SIP server checks and records a call state of the wireless terminal for each access point, and limits the number of calls under the same access point.   The VoIP system according to claim 1, wherein the identification information is an identification ID of an access point used by the wireless terminal and individual identification information of the wireless terminal. The VoIP system according to claim 1 or 2 , wherein the management table includes a field for recording a MAC address of a wireless terminal. The VoIP system according to any one of claims 1 to 3 , wherein when the wireless terminal is connected to the access point or when the connection is changed to another access point, the identification information is notified to a SIP server. The VoIP system according to any one of claims 1 to 4 , wherein the identification information is notified from the wireless terminal to the SIP server by a Register message to which a header field for notifying the BSSID of the access point is added.

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