VoIP COMMUNICATION CONTROL METHOD AND ACCESS POINT APPARATUS

Abstract

A critical threshold value of the number of connections of VoIP communication by a wireless LAN is set to an access point apparatus. The access point apparatus records identification information of terminals each of which has transmitted a request for connection of VoIP communication. After the number of terminals whose identification information have been recorded reaches the critical threshold value, the access point apparatus transmits a packet indicating release an association to a terminal whose identification information is newly recorded.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an arrangement view of a wireless LAN system to which the present invention is applied;

FIG. 2 is a detailed arrangement view of a wireless LAN access point of an embodiment 1;

FIG. 3 is a flowchart explaining an operation of the embodiment 1;

FIG. 4 is a detailed arrangement view of a wireless LAN access point of an embodiment 2;

FIG. 5 is a flowchart explaining an operation of the embodiment 2; and

FIG. 6 is a flowchart explaining an operation of an embodiment 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A best mode of the present invention will be explained with reference to the drawings.

In a wireless LAN system, a system composed of one access point and a terminal that communicates with the access point is called a basic service set. A connection network for connecting basic service sets with each other is called a distribution system.

In the basic service set, a procedure for causing terminals to belong to an access point is called an association. A management list of the terminals belonging to the access point is created by the association. Since the list is supplied to the distribution system, a terminal can communicate with other terminal and other system through the access point. It is called disassociation to release the association.

Embodiment 1

FIG. 1 shows an arrangement of a system to which the present invention is applied. The system 1000 includes an access point (AP) 100 operated under the control of a program and VoIP terminals 101 and 102 which can communicate with each other.

The AP 100 is a wireless LAN access point apparatus for controlling the number of connections of VoIP terminals to be connected to a wireless LAN. The VoIP terminal 101 is a VoIP terminal acting as a wireless LAN client and connected to the AP 100 by the wireless LAN. The VoIP terminal 102 is connected to the AP 100 through a wired LAN 103 and can carries out a VoIP call to the VoIP terminal 101.

FIG. 2 shows a detailed arrangement of the AP 100 of the embodiment 1. The AP 100 includes a ROM 201, a CPU 202, a RAM 203, a wireless LAN unit 204, and a wired LAN unit 205.

The ROM 201 includes a control program 201a executed by the CPU 202, a critical threshold value 201b as set data used to execute the program, and a bit train 201c. Although the critical threshold value 201b and the bit train 201c may be previously written to the control program 201a, it may be written by a person in charge of an engineering work independently of the program. The CPU 202 carries out an arithmetic operation processing for controlling the number of VoIP calls and the like by executing the control program 201a. The RAM 203 acts as the working area of the CPU 202. Further, the RAM 203 has a MAC address table 203a for recording the number of connections of the VoIP terminal. The CPU 202 records the MAC addresses of the terminals to be connected and the number of terminals in communication at the time to the MAC address table 203a. The wireless LAN unit 204 takes charge of a wireless LAN communication function based on IEEE 802.11. The wired LAN unit 205 takes charge of a wired LAN communication function based IEEE 802.3.

An operation of the embodiment 1 will be explained with reference to the flowchart of FIG. 3. In this explanation, SIP (Session Initiation Protocol) is applied as a call control protocol for carrying out a VoIP communication for the purpose of convenience. Other call control protocols such as H.323, MGCP (Media Gateway Control Protocol), and the like may be applied in place of SIP.

The AP 100 monitors all the packets transmitted from and received by the VoIP terminal 101 connected to the wireless LAN (step S1).

The AP 100 determines whether or not the content of description of a packet being monitored agrees with the transmission/reception command included in the bit train 201c of the ROM 201 (step S2). In the SIP, the transmission/reception command corresponds to an INVITE command which is used as a transmission command and a reception command for requesting connection of the VoIP communication.

When the content of the packet is the INVITE command as a result of determination (step S2: Yes), the AP 100 confirms whether or not the MAC address of the VoIP terminal 101 included in the packet exists in the MAC address table 203a of the RAM 203 (step S3).

When the MAC address of the target is already registered to the MAC address table 203a as the result of determination (step S3: Yes), the process goes to a processing of other packet to be monitored. When the MAC address is not yet registered (step S3: No), the AP 100 registers the MAC address of the VoIP terminal 101 included in the packet to the MAC address table 203a (step S4).

The AP 100 determines whether or not the number of MAC addresses registered to the MAC address table 203a, that is, the number of VoIP calls at the time exceeds the preset critical threshold value 201b (step S5). The critical threshold value 201b is an upper limit value prescribed to the AP 100 as to the number of connections of the VoIP calls.

When the number of the registered MAC addresses does not exceed the critical threshold value 201b as a result of determination, (step S5: No), the process goes to a processing of other packet to be monitored. When the number of the registered MAC addresses exceeds the critical threshold value 201b (step S5: Yes), the AP 100 transmits a Dis-Association command determined by IEEE 802.11, that is, a command indicating to release the association to the VoIP terminal 101 acting as the transmission source or the transmission destination of the INVITE command (step S6). The VoIP terminal 101 that receives the Dis-Association command is disconnected from wireless LAN.

In case the VoIP terminal 101 is disconnected from wireless LAN, the VoIP communication of the VoIP terminal 101 is not established. After transmitting the Dis-Association command, the AP 100 deletes the MAC address which registered to the MAC address table 203a as to the VoIP terminal 101.

When the content of description of the packet being monitored does not agree with the transmission/reception command (step S2: No), the AP 100 determines whether or not the content of description agrees with a disconnection command (“BYE”) included in the bit train 201c of the ROM 201 (step S7).

When the content of description of the packet does not also agree with the disconnection command as a result of determination (step S7: No), the process goes to a processing of other packet to be monitored. When the content of description of the packet agrees with the disconnection command (step S7: Yes), the AP 100 recognizes that the VoIP communication of the VoIP terminal 101 has finished and deletes the MAC address of the VoIP terminal 101 from the MAC address table 203a (step S8).

Embodiment 2

FIG. 4 shows a detailed arrangement of an AP 100 of a second embodiment. FIG. 5 is a flowchart showing an operation of the AP 100 of the second embodiment. Although the AP 100 of the second embodiment is fundamentally has the same arrangement as that of the embodiment 1 described above (FIG. 2), it is different from the embodiment described above in that a call status is added to a MAC address to show a call status of a VoIP terminal. The MAC address table 303a has “during a call” or “call finished” recorded thereto as the call status of the terminal.

The operation of the second embodiment will be explained referring to the flowchart of FIG. 5.

The AP 100 monitors all the packets transmitted from and received by a VoIP terminal 101 connected to a wireless LAN (step S11).

The AP 100 determines whether or not the content of description of a packet being monitored agree with a transmission/reception command (“INVITE”) included in a bit train 301c of a ROM 301 (step S12).

When the description of the packet agrees with the INVITE command as a result of determination (step S12: Yes), the AP 100 confirms whether or not the MAC address of the VoIP terminal 101 included in the packet exists in a MAC address table 303a of a RAM 303 (step S13).

When the MAC address of the target is already registered to the MAC address table 303a as a result of determination (step S13: Yes), the AP 100 determines whether or not the call status associated with the MAC address is “during a call” (step S18).

When the call status is “during a call” as a result of determination (step S18: Yes), the process goes to a processing of other packet to be monitored. Further, when the call status is “call finished” (step S18: No), the AP 100 changes the call status of the VoIP terminal 101 to “during a call” in the MAC address table 303a (step S15).

In contrast, when the MAC address of the target is not yet registered to the MAC address table 303a (step S13: No), the AP 100 associates the MAC address with the call status of “during a call” and registers them to the MAC address table 303a (steps S14, S15).

The AP 100 determines whether or not the number of MAC addresses associated with the call status of “during a call”, that is, the number of terminals in a VoIP call exceeds a critical threshold value 301b in the MAC address table 303a (step S16). The critical threshold value 301b used in the determination may be the same as or different from the critical threshold value 201b of the embodiment 1.

When the number of VoIP calls does not exceed the critical threshold value 301b as a result of determination (step S16: No), the process goes to a processing of other packet to be monitored. When the number of calls exceeds the critical threshold value 301b (step S16: Yes), the AP 100 transmits a Dis-Association command indicating to release an association to the VoIP terminal 101 acting as a transmission source or a transmission destination of the INVITE command and to the VoIP terminal 101 whose call status is “call finished” (step S17). In this case, the terminal to which “call finished” is recorded is a terminal which carried out a VoIP call in the past but does not carry out a VoIP call at this time as well as which is in the state that a communication session with the AP 100 is continued. The VoIP terminal 101 which receives the Dis-Association command is disconnected from a wireless LAN.

The AP 100 changes the call status of the VoIP terminal 101, which is disconnected from wireless LAN after the call status of it is set to “during a call”, to “call finished” (step S21).

When the content of description of the packet being monitored does not agree with the transmission/reception command (step S12: No), the AP 100 determines whether or not the content of description thereof agrees with a disconnection command (“BYE”) included in the bit train 301c of the ROM 301 (step S19).

When the content of description of the packet does not also agree with the disconnection command (step S19: No), the process goes to a processing of other packet to be monitored. When the content of description of the packet agree with the disconnection command (step S19: Yes), the AP 100 determines whether or not the call status of the VoIP terminal is “during a call” (step S20).

When the call status is “call finished” as a result of determination (step S20: No), the process goes to a processing of other packet to be monitored. Further, when the call status is “during a call” (step S20: Yes), the AP 100 changes the call status of the VoIP terminal to “call finished” (step S21).

As described above, in the second embodiment, when the number of connections of the terminals in the AP 100 exceeds the critical threshold value, not only a terminal, which intends to newly start a VoIP call, but also a “call finished” terminal, which is being connected to the wireless LAN, are disconnected from the wireless LAN. With this operation, the “call finished” terminal can be prevented from resuming a VoIP call.

Note that since a terminal, which is connected to the wireless LAN regardless that it is not a VoIP terminal, is not disconnected therefrom in the second embodiment, it can carry out a data communication.

Embodiment 3

FIG. 6 is a flowchart explaining an operation of a third embodiment. The third embodiment relates to a control of an AP 100 when a “call finished” VoIP terminal, which is disconnected in the second embodiment, newly issues a request for connection.

An operation of the third embodiment will be explained referring to the flowchart of FIG. 6.

When the AP 100 receives a message for confirming possibility of connection such as “Association Request” based on IEEE 802.11 or “Probe Request” from a “call finished” VoIP terminal in a MAC address table 303a (step S30), the AP 100 determines whether or not the number of “during a call” MAC addresses, that is, the number of terminals in a call at the time exceeds a critical threshold value 301b (step S31).

When the number of terminals in a call at the time exceeds the critical threshold value as a result of determination (step S31: Yes), the AP 100 rejects the request for connection (step S32). Specifically, the AP 100 ignores “Association Request” or “Probe Request” transmitted from the VoIP terminal.

When the number of terminals in a call at the time does not exceed the critical threshold value (step S31: No), the AP 100 permits connection of the VoIP terminal to the wireless LAN (step S33).

According to the third embodiment, even if the “call finished” VoIP terminal, which is disconnected from the wireless LAN in the second embodiment tries new connection, it is possible to control the terminal such that it is not connected to the same access point again as long as the number of VoIP calls exceeds the critical threshold value.

The present invention can be applied to a streaming communication such as VoIP, a moving image communication, and the like in the wireless LAN system based on IEEE 802.11. The present invention can be also applied to an on-demand delivery service antenna for delivering music and moving images from the Internet. Further, the present invention can be also applied to a radio communication other than IEEE 802.11.

Although the exemplary embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions and alternatives can be made therein without departing from the sprit and scope of the invention as defined by the appended claims. Further, it is the inventor's intent to retrain all equivalents of the claimed invention even if the claims are amended during prosecution.

Claims

1. A VoIP communication control method comprising: setting a critical threshold value of the number of connections of VoIP communication through an access point apparatus by a wireless LAN;recording identification information of terminals each of which has transmitted a request for connection of VoIP communication; andtransmitting a packet indicating release an association from the access point apparatus to a terminal whose identification information is newly recorded after the number of terminals whose identification information have been recorded reaches the critical threshold value.

2. A VoIP communication control method of claim 1, further comprising: deleting the identification information of the terminal to which the packet indicating release an association is transmitted.

3. A VoIP communication control method of claim 1, further comprising: recording status information indicating during a call in association with the identification information to be recorded;changing the status information indicating during a call to status information indicating the call finished when a request for disconnection from VoIP communication is transmitted from the terminal whose status information indicating during a call has been recorded;changing the status information indicating the call finished to status information indicating during a call when a request for connection of VoIP communication is transmitted from the terminal whose the status information indicating call finished has been recorded; andtransmitting a packet indicating release an association to a terminal whose status information indicating during a call is newly recorded when the number of terminals whose status information indicating during a call have been recorded reaches the critical threshold value.

4. A VoIP communication control method of claim 3, further comprising: transmitting a packet indicating release an association to the terminal whose status information indicating the call finished has been recorded when the number of terminals whose status information indicating during a call have been recorded reaches the critical threshold value.

5. A VoIP communication control method of claim 1, wherein the identification information of the terminal to be recorded is MAC address of the terminal; and wherein the packet indicating to release an association is a Dis-Association packet based on IEEE 802.11.

6. An access point apparatus comprising: a memory in which a critical threshold value of the number of connections of VoIP communication by a wireless LAN and a control program are stored anda CPU for executing the control program;wherein the CPU records identification information of terminals each of which has transmitted a request for connection of VoIP communication to the memory and transmits a packet indicating release an association to a terminal whose identification information is newly recorded after the number of terminals whose identification information have been recorded reaches the critical threshold value.

7. An access point apparatus of claim 6, wherein the CPU deletes the identification information of the terminal to which the packet indicating release an association is transmitted.

8. An access point apparatus of claim 6, wherein the CPU records status information indicating during a call in association with the identification information to be recorded to the memory,changes the status information indicating during a call to status information indicating the call finished when a request for disconnection from VoIP communication is transmitted from the terminal whose status information indicating during a call has been recorded,changes the status information indicating the call finished to status information indicating during a call when a request for connection of VoIP communication is transmitted from the terminal whose the status information indicating call finished has been recorded, andtransmits a packet indicating release an association to a terminal whose status information indicating during a call is newly recorded when the number of terminals whose status information indicating during a call have been recorded reaches the critical threshold value.

9. An access point apparatus of claim 8, wherein the CPU transmits a packet indicating release an association to the terminal whose status information indicating the call finished has been recorded when the number of terminals whose status information indicating during a call have been recorded reaches the critical threshold value.

10. An access point apparatus of claim 6, wherein the CPU records a MAC address as the identification information of the terminal to be recorded to the memory and transmits a Dis-Association packet based on IEEE 802.11 as the packet indicating to release an association.