JP2008054162A - Congestion regulation system, device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a congestion regulation device capable of detecting and regulating abnormal congestion without inclining to a specific session. <P>SOLUTION: The present invention provides a congestion regulation device provided in a communication system that transfers messages and responses concerning call processing protocols such as establishment and disconnection of a session via a network for transferring packets between a communication terminal and a call processor. Then, the congestion regulation device is characterized by including a call amount measurement means for measuring "arrival frequency/time" for prescribed kinds of messages from the communication terminal to the call processor as a call amount at the point of time, a regulation judgment means for comparing the measured call amount with a threshold to judge whether or not the call amount is at a congestion state and a regulation means for discarding the prescribed kinds of messages arrived when the call amount is at the congested state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a congestion regulation system, apparatus, and program, and can be applied to, for example, an attempt to reduce the adverse effects of congestion on an IP telephone system.

  Recently, IP telephones have become widespread, and congestion in IP telephone systems is being studied. A traffic control system (TCS) and a countermeasure system using a telephone exchange for planned congestion (concentration at ticket reservation centers, etc.) and disaster-type congestion (concentration in the affected area), which has been realized with conventional telephone systems, In the IP telephone system, it is possible to take countermeasures using almost the same method.

  However, in the case of abnormal congestion (unpredictable call concentration, etc.), the call agent (CA) in charge of call processing is congested with the CPU, making it difficult to connect to the telephone, and delay is a problem even in normal conditions. Packet congestion in easy-to-use networks causes degradation of sound quality due to packet discarding.

Therefore, a method for controlling congestion in the IP telephone system has already been proposed. For example, Patent Document 1 discloses that a session control device adjacent to or incorporated in a session setting device measures congestion by measuring a session incomplete rate or session arrival rate for each group, and an incoming terminal belonging to a group in which congestion is detected. It describes that congestion control is performed by regulating session requests for
JP 2005-167771 A

  However, in the congestion control method of Patent Document 1, congestion is detected based on the incompletion rate or arrival rate of a session, congestion that is not biased toward a specific session cannot be detected, and such congestion cannot be regulated. There is.

  Therefore, there is a demand for a congestion regulation system, device, and program that can detect and regulate abnormal congestion that is not biased toward a specific session.

  In order to solve this problem, according to the first aspect of the present invention, a message and a response relating to a call processing protocol such as session establishment and disconnection are exchanged between a communication terminal and a call processing device via a network for transferring packets. A congestion control device provided in a communication system, wherein (1) “arrival frequency / time” of a first predetermined type of message from the communication terminal to the call processing device is measured as a call volume at that time And (2) a regulation determination unit that compares the measured call volume with a threshold value to determine whether or not it is in a congestion state, and (3) that has arrived when the congestion state is determined. And restricting means for discarding two predetermined types of messages.

  A congestion restriction system according to a second aspect of the present invention is a communication system that exchanges messages and responses related to call processing protocols such as session establishment and disconnection between a communication terminal and a call processing device via a network for transferring packets. The congestion control device according to the first aspect of the present invention is provided.

  A congestion restriction program according to a third aspect of the present invention is a communication system that exchanges messages and responses related to call processing protocols such as session establishment and disconnection between a communication terminal and a call processing device via a network that transfers packets. A call volume measuring means for measuring the “arrival frequency / time” of the first predetermined type of message from the communication terminal to the call processing device as the call volume at that time. It is possible to function as a restriction determination unit that compares a call volume with a threshold value and determines whether or not a congestion state occurs, and a restriction unit that discards a second predetermined type of message that has arrived when the congestion state is determined. Features.

  According to the congestion regulation system, apparatus, and program of the present invention, it is possible to detect and regulate abnormal congestion that is not biased toward a specific session in real time.

(A) One Embodiment Hereinafter, an embodiment in which the congestion regulation system, apparatus, and program according to the present invention are applied to congestion regulation according to an IP telephone system.
This will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 1 is a block diagram showing the overall configuration of the congestion regulation system of this embodiment. In FIG. 1, in the congestion restriction system 1 of this embodiment, a congestion restriction device 4 is provided at the boundary of a network 3 that accommodates a call agent (CA) 2 and provides an IP telephone system. That is, the IP phone dedicated terminals 5-1 and 5-2 and the soft phones 6-1 and 6-2 realized on the personal computer (PC) are connected to the network 3 side only through the congestion control device 4. The congestion regulating device 4 is provided at a position where it can be accessed. The IP phone dedicated terminal (5-2) and the soft phone (6-2) may be elements of the LAN7. In the following description, IP phone dedicated terminals, soft phones, and the like are collectively referred to as IP phone terminals.

  As is well known, the call agent 2 performs association processing between a telephone number and an IP address, linkage control between a public telephone network and an IP network, call and signaling control, and the like.

  The congestion regulation device 4 that characterizes this embodiment is constructed by installing a congestion regulation program in a computer having a communication function, for example. In addition, the congestion control apparatus 4 may be constructed as a dedicated apparatus, or may be constructed using a general-purpose computer. Further, the congestion control device 4 may be realized as one function of a device in charge of a predetermined function such as an Internet service provider (ISP) server or router.

  The congestion restriction device 4 is a device that performs congestion restriction processing, and functionally includes a call volume measurement unit 11, a restriction determination unit 12, and a restriction unit 13, as illustrated in FIG.

  The call volume measuring unit 11 analyzes a SIP message exchanged between the IP telephone terminal (5-1, 5-2, 6-1, 6-2, etc.) and the call agent 2, and measures the call volume. Is. Details of the processing of the call volume measuring unit 11 will be described in the section of operation.

  The restriction determination unit 12 determines whether or not the restriction is necessary (congestion state) by comparing the call amount measured by the call amount measurement unit 11 with a predetermined restriction value (threshold value). Details of the processing of the restriction determination unit 12 will be described in the operation section.

  The restricting unit 13 basically discards a call message that has arrived when the restriction determining unit 12 determines that a restriction is necessary, and notifies the transmission source side of the call message. In the case of this embodiment, the restriction unit 13 excludes priority calls and calls from priority subscribers even when the restriction determination unit 12 determines that the restriction is necessary. is there. Details of the processing of the restricting unit 13 will be described in the section of operation.

(A-2) Operation | movement of embodiment Next, operation | movement of the congestion control apparatus 4 in the congestion control system 1 of this embodiment is demonstrated. The operations other than the congestion control device 4 are the same as those in the conventional one.

  First, the call volume measuring operation by the call volume measuring unit 11 will be described with reference to FIG. FIG. 2 is a flowchart showing a call volume measuring operation by the call volume measuring unit 11.

  When receiving a SIP message as will be described later, the call volume measuring unit 11 starts the processing shown in FIG. 2 and determines whether or not the received message is an INVITE message (step 100). If the received message is not an INVITE message, the series of processing shown in FIG. 2 is terminated. If the received message is an INVITE message, the value of the INVITE message number counter (soft counter) is incremented by 1 (step 101). The series of processes shown in FIG.

  Here, the SIP message for starting the processing of FIG. 2 is a SIP message from the IP telephone terminal (5-1, 5-2, 6-1, 6-2, etc.) to the call agent 2. For example, the SIP message relates to an IP packet that satisfies the condition that the destination IP address is a specified value, the protocol is a specified value, and the destination port is a specified value.

  Further, as will be described later, the value of the INVITE message number counter is cleared periodically (every second).

  As described above, in this embodiment, since the call volume is measured as the number of INVITE messages, the call volume can be captured almost in real time. As a result, even when congestion occurs, the call volume is almost real time. You can catch that.

  Next, the restriction determination operation by the restriction determination unit 12 will be described with reference to FIG. FIG. 3 is a flowchart showing the restriction determination operation by the restriction determination unit 12.

  For example, the restriction determination unit 12 starts the restriction determination process illustrated in FIG. 3 as a periodic process every second, and first determines whether the value of the INVITE message number counter at that time exceeds the restriction value. (Step 150). The value of the INVITE message number counter at this time is the number of INVITE messages that have arrived in the previous one second, and as described above, the call volume can be grasped almost in real time.

  When the value of the INVITE message number counter exceeds the restriction value, the restriction determination unit 12 sets a restriction state flag (= TRUE) (step 151), while the value of the INVITE message number counter is equal to or less than the restriction value. Then, the restriction state flag is reset (= FALSE) (step 152). The setting and resetting of the restriction state flag corresponds to whether or not there is a congestion state. Here, when the restriction value is set high, it is difficult to determine the congestion state, and when the restriction value is set low, it is easy to determine the congestion state.

  When the restriction state flag is set, this may be notified to the management center device (eg, TCS).

  Thereafter, the restriction determination unit 12 clears the value of the INVITE message number counter (step 153), and ends the series of processes shown in FIG.

  Next, the regulation operation by the regulation unit 13 will be described with reference to FIG. FIG. 4 is a flowchart showing the regulation operation by the regulation unit 13.

  As in the case of the call volume measurement unit 11, the regulation unit 13 outputs a SIP message that satisfies a predetermined condition from the IP telephone terminal (5-1, 5-2, 6-1, 6-2, etc.) to the call agent 2. When received, the process shown in FIG. 4 is started, and first, it is determined whether or not a restriction state flag is set (step 200). If the restriction state flag is not set (if it is not congested), there is no need for restriction, and the series of processes shown in FIG.

  On the other hand, if the restriction state flag is set, it is determined whether or not the received SIP message is a reINVITE message (step 201). The reINVITE message is a message for transmitting call connection maintenance to the call agent 2, and is a message unsuitable for discarding even in a congested state. That is, when the reINVITE message does not reach the call agent 2 due to the discard, the call agent 2 misunderstands that the established session is disconnected, and thus is not suitable for discard. Therefore, when the received SIP message is a reINVITE message, the series of processing shown in FIG. 4 is terminated, and the reINVITE message is not discarded even in a congested state.

  If the received SIP message is not a reINVITE message, it is determined whether or not the received message is an INVITE message (step 202). In this embodiment, the message to be discarded is defined only as the INVITE message. Therefore, if the received SIP message is not an INVITE message, the series of processes shown in FIG. 4 is terminated, and the received message is not discarded even in a congested state.

  If the received SIP message is an INVITE message, it is determined whether the INVITE message is a message related to a priority call or a message related to a priority subscriber (step 203).

  A priority call refers to a call for which priority should be given to session establishment regardless of a contract with a subscriber, such as a call related to an emergency call (for example, “110”). The restricting unit 13 holds a priority call number (not necessarily one) in advance, compares the called number of the received INVITE message with the held priority call number, and the called number matches the priority call number. If so, it is determined as a priority call. A priority subscriber refers to a call for which priority should be given to session establishment by a contract with the subscriber. The restricting unit 13 holds a priority subscriber ID (not necessarily one) in advance, and the content of a predetermined item (for example, a VLAN identifier) of the received INVITE message is stored as a priority subscriber ID. In comparison, if the content of the predetermined item matches the priority subscriber ID, it is determined as a priority subscriber.

  If the received INVITE message is a message related to a priority call or a message related to a priority subscriber, the series of processes shown in FIG. 4 is terminated, and the received message is not discarded even in a congested state.

  If the received INVITE message is neither a message relating to a priority call nor a message relating to a priority subscriber, the restriction unit 13 discards the received INVITE message (step 204), and 503 is sent to the transmission source of the received INVITE message. A response is returned (step 205), and the series of processing shown in FIG. The 503 response is a response to the incoming SIP message indicating service invalidity (Service Unavailable) (other busy responses may be applied). In addition to the response of the 503 response, discard of the received INVITE message may be notified to the management center device (eg, TCS).

  By the process shown in FIG. 4 as described above, in the restricted state, the INVITE message related to the priority call and other than the priority subscriber is discarded, and the reINVITE message is not discarded.

(A-3) Effect of the Embodiment According to the above embodiment, it is determined whether or not the congestion state is based on the call volume measured for the INVITE message instead of the traffic volume of the IP packet. Congestion (traffic) can be regulated by detecting congestion in real time, including abnormal congestion that is not biased toward the real time. When congestion is restricted and traffic is suppressed to a certain level or less, the influence of propagation delay and delay fluctuation in the network 3 can be suppressed, and deterioration of sound quality of the IP telephone can be prevented.

  Further, since the restriction is discarding of the INVITE message, congestion can be restricted without establishing a session (without generating voice data traffic), and the efficiency of restriction can be increased.

  Furthermore, priority calls such as emergency calls and priority subscribers by contract can be excluded from the restriction, and priority control can be introduced in congestion regulation. For planned congestion (concentration at the ticket reservation center, etc.) and disaster congestion (concentration in the affected area), the operator will make a priority call or priority subscription regarding the traffic concentration destination (concentration prediction destination). This can be done by registering the person.

  Furthermore, it is congestion restriction control using the SIP message, and it is possible to notify the restriction state by returning a busy response to the call of the subscriber.

  In the above embodiment, since the congestion control device 4 provided at the boundary of the network 3 providing the IP telephone system controls the congestion, the SIP message reaching the call agent 2 is suppressed, and as a result, The upper limit of the processing load of the call agent 2 is suppressed, and the processing delay is also suppressed to a certain extent.

(B) Other Embodiments In the above embodiment, the call volume measurement is performed regardless of the transmission source / destination. However, measurement is performed in units of transmission sources (group concept may be introduced), Alternatively, a combination of a transmission source / destination (a group concept may be introduced) is measured in units, and a restriction determination operation or a restriction operation may be performed in that unit. In the case where the congestion restriction process is performed in such a predetermined unit, information such as a transmission source causing the congestion may be automatically registered in the black list when the call volume exceeds the restriction value.

  In the above embodiment, the restriction value used for the restriction determination operation is fixed. However, if the previous determination result is a set of restriction state flags, a restriction value that is one step lower than the previous restriction value is set. You may make it apply. If this is done, there is a high possibility that it will be determined as congestion this time, and there is a high possibility that the discard rate of the INVITE message will be high. That is, the longer the congestion state, the higher the message discard rate, which can contribute to speeding up the avoidance of the congestion state.

  Further, in the above embodiment, the call volume (congestion state) is shown as the number of INVITE messages per predetermined time, but the time required for the number of INVITE messages to be a predetermined number is used as a call volume parameter. You may do it.

  In the above embodiment, the SIP message used for measuring the call volume is the INVITE message. However, another SIP message may be used for measuring the call volume. For example, a REGISTER (registration) message may be used. In this case, the number of SIP messages and REGISTER messages may be counted separately, and the restriction determination operation and the restriction operation may be performed separately. The total number of SIP messages and REGISTER messages is counted, and based on the total number. Thus, the regulation determination operation and the regulation operation may be performed in combination. Note that when the REGISTER message is used, the reREGISTER message that transmits the registration maintenance of the IP telephone terminal to the call agent 2 is excluded from the restriction even in the restricted state.

  In each of the above-described embodiments, the IP phone dedicated terminal and the soft phone are shown as the IP phone terminal, but other terminals may be used. For example, it may be an IP facsimile terminal or a portable terminal.

  In each of the above embodiments, the congestion control device has been described as an independent device that is not associated with the call agent. However, although the effect of reducing the processing load on the call agent cannot be obtained, as one function of the call agent, A congestion control device may be provided as a peripheral device for the agent.

  In the above embodiment, the case where the present invention is applied to an IP telephone system has been shown. However, the present invention is also applied to a communication system that provides other services (for example, home appliance control service, home care service, etc.). can do. In short, the present invention can be applied to any communication system that applies SIP or a protocol similar to SIP as a protocol applied to session establishment or the like.

It is a block diagram which shows the whole structure of the congestion control system of embodiment. It is a flowchart which shows the call volume measurement operation | movement of embodiment. It is a flowchart which shows the regulation determination operation | movement of embodiment. It is a flowchart which shows the control operation | movement of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Congestion control system, 2 ... Call agent (CA), 3 ... Network, 4 ... Congestion control apparatus, 5-1, 5-2 ... IP telephone dedicated terminal, 6-1, 6-2 ... Soft phone, 11 ... Call volume measurement unit, 12 ... restriction determination unit, 13 ... restriction unit.

Claims (6)

A congestion control device provided in a communication system that exchanges messages and responses related to a call processing protocol such as session establishment and disconnection via a network for transferring packets between a communication terminal and a call processing device,
Call volume measuring means for measuring “arrival frequency / time” of a first predetermined type of message from the communication terminal to the call processing device as a call volume at that time;
A restriction determination means for comparing the measured call volume with a threshold value and determining whether or not the congestion state;
And a restricting means for discarding a second predetermined type of message that has arrived when the congestion state is determined.   The congestion regulating apparatus according to claim 1, wherein both the first predetermined type message and the second predetermined type message are call messages.   The restricting means holds preferential message information that is not subject to restriction, and even if it is the second predetermined type of message that has arrived when it is determined to be in a congestion state, The congestion control device according to claim 1 or 2, wherein when the message information matches the priority message information, the message is not discarded.   The congestion control apparatus according to claim 1, wherein when the incoming message is discarded, the restriction unit responds to a predetermined type of response to the transmission source of the message.   5. The communication system according to claim 1, wherein the communication terminal and the call processing device exchange a message and a response related to a call processing protocol such as establishment or disconnection of a session via a network for transferring packets. A congestion control system characterized by providing a congestion control device. A computer provided in a communication system that exchanges messages and responses related to a call processing protocol such as session establishment and disconnection via a network that transfers packets between a communication terminal and a call processing device,
Call volume measuring means for measuring “arrival frequency / time” of a first predetermined type of message from the communication terminal to the call processing device as a call volume at that time;
A restriction determination means for comparing the measured call volume with a threshold value and determining whether or not the congestion state;
A congestion restriction program that functions as a restriction unit that discards a second predetermined type of message that has arrived when it is determined that a congestion state has occurred.

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