JP2009200658A - Media gateway apparatus and event transmission method used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a media gateway apparatus capable of mounting an event buffer function used for monitoring the service level of speech communication quality or the like even when assuming such large scale subscriber holding that call information to be handled increases by the increase of a subscriber holding capacity. <P>SOLUTION: A media gateway (MG1) includes a means (call information management unit 12) for storing an event state detected when a session with an MGC is disconnected, and a means (MGC transmission and reception unit 11) for performing the retrieval processing of an event held by a termination unit when the session is established again and autonomously transmitting the retrieved results to the media gateway controller. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a media gateway device and an event transmission method used therefor. The present invention relates to an event transmission method of MG (Media Gateway) using the H.248 / MEGACO protocol.

  ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) Recommendation The functional requirements when the event buffer descriptor (Event Buffer Descriptor) defined in H.248 is implemented in MG are shown below.

  1. An event buffer is provided for each termination unit. When an event occurs, the event is added to the event buffer, and simultaneously notify is transmitted.

  2. The event added to the event buffer is held until the event descriptor (Events Descriptor) of the corresponding termination is changed in state by Modify or the termination itself is deleted.

  In the MG related to the present invention, in order to satisfy the functional requirements shown above, It is necessary to prepare a FIFO (First In First Out) buffer for storing events generated as specified in H.248 in a list.

  In VoIP (Voice over IP) services such as IP (Internet Protocol) telephones, when performing communication between networks having different policies, from the viewpoint of NGN (Next Generation Network) that guarantees service quality in units of subscribers. An event monitoring function implemented in MG or MG is required.

The following Patent Document 1 describes a technique for monitoring an event set in advance by the MG and reporting the monitoring result to an MGC (Media Gateway Controller).
JP 2006-304298 A

  In MG related to the present invention, H.C. Since it is necessary to prepare a FIFO buffer for storing events generated as listed in H.248, when the termination increases, the number of generated events also increases, and the size of the FIFO buffer that manages this increases. Problems such as increased memory usage and search processing delays occur. This makes it difficult to realize an MG that accommodates large-scale termination information.

  In addition, if the implementation is such that notify is sent when an event occurs without using a FIFO buffer, the event that occurred during the session disconnection cannot be retained, so the event that occurred during the session disconnection is sent to the MGC. Problems such as inability to notify. With the technique described in Patent Document 1, since the monitoring result of a preset event is only reported to the MGC, the above problem cannot be solved.

  Therefore, the object of the present invention is to solve the above-mentioned problems, and even when assuming large-scale subscriber accommodation in which call information to be handled increases as the number of subscriber accommodation increases, the service level such as call quality is improved. An object of the present invention is to provide a media gateway device that can implement an event buffer function used for monitoring and an event transmission method used therefor.

  The media gateway device according to the present invention stores means for storing an event state detected in a state where a session with the media gateway controller is disconnected, and an event held in a termination unit in a state where the session is re-established. Means for performing a search process and autonomously transmitting the search result to the media gateway controller.

  The event transmission method according to the present invention includes a step in which a media gateway device stores an event state detected in a state in which a session with a media gateway controller is disconnected, and a unit of termination in a state in which the session is reestablished. Performing the event search process and autonomously transmitting the search result to the media gateway controller.

  The present invention has a service level such as call quality even when assuming large-scale subscriber accommodation in which call information handled increases as the number of subscriber accommodation increases due to the configuration and operation as described above. The effect that the event buffer function used to monitor the event can be implemented is obtained.

  Next, embodiments of the present invention will be described with reference to the drawings. First, a media gateway device [hereinafter referred to as MG (Media Gateway)] according to the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration example of an MG according to the present invention. In FIG. 1, the MG 1 includes an MGC (Media Gateway Controller) transmission / reception unit 11, a call information management unit 12, and a packet transfer unit 13.

  According to the present invention, an MG that converts a protocol or the like installed at a network boundary having a different operation policy is converted from MGC to ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) recommendation H.264. The present invention relates to a case where control is performed using H.248 / MEGACO.

  The MG 1 according to the present invention stores an event state detected in a state in which the session is disconnected by the call information management unit 12, and in a state in which the session is re-established by the MGC transmission / reception unit 11, termination. It speeds up the event search process held in the unit and sends it autonomously.

  As a result, the MG1 according to the present invention speeds up and reliably performs event transmission by notification to the MGC. Further, the MG 1 according to the present invention can quickly detect a network failure or the like, and can maintain a service level such as call quality of IP (Internet Protocol) telephone and video distribution.

  The MG used in the present invention is a generic term for media gateways used at network boundaries with different operation policies, a function for allocating transmission resources in units of subscribers and flows, a bandwidth control and traffic marking control function, and a NAT (Network Address). (Translator) / NAPT (Network Address-Port Translator) control function, pinhole control function to prevent unauthorized traffic from flowing into the core network, quality monitoring function to monitor the network status by monitoring packet transfer rate, It shall have SBC (Session Border Controller) functions such as a monitor function for copying and transferring a specific flow to a specified destination.

  As an example of MG, TISPAN (The Telecoms & Network for Network) is one of the standards organizations of ETSI (European Communications Standards Institute) and TISPAN (The Telecoms & Network N BGF (Border Gateway Function) and RCEF (Resource) conforming to the Resource and Admission Control Subsystem (RACS) architecture for realizing QoS (Quality of Service) functions It is equivalent to the ontrol Enforcement Function) function.

  MGC used in the present invention is ITU-T recommendation H.264. It is assumed that call information such as termination and context is set for the MG using 248 / MEGACO. Here, ITU-T Recommendation H.264 In 248 / MEGACO, a logical element called a context is used as a control target base, and termination is associated with the context for control.

  An example of the MGC is equivalent to a function of A-RACF (Access-Resource and Admission Control Function) in the above-described RACS architecture or a control device provided with a Service Policy Decision Function (SPDF).

  The session used in the present invention represents a communication state between the MGC and the MG. The session is established when the communication can be normally performed, and the session is established when the communication cannot be performed due to a communication path failure or a MGC failure. Shall be disconnected.

  In the network configuration according to the present invention, a signaling protocol such as SIP or RTP (Real) is transmitted from the first SIP (Session Initiation Protocol) client to the second SIP client via the first network, the MG, and the second network. -In order to enable communication using a media communication protocol such as time transport protocol), the operation policy is converted from the first network to the second network based on the termination information registered in the MG. Shall. Also, the termination setting is performed from the MGC to the MG via the third network.

  An example of an event that occurs in the present invention is H.264. A Quality Alert (nt / qualert) event is set to monitor the call quality at the termination specified in H.248, and a notification is sent to the MGC when the communication state of the flow that matches the termination falls below the set threshold. There is a mechanism to do.

  As an example of use of this apparatus, when an event for monitoring call quality is set for a media communication flow between a first SIP client and a second SIP client via MG, the flow is set. It is assumed that notify is transmitted from the MG to the MGC via the third network when the rate falls below the threshold value.

  In the present invention, H.P. When the event buffer function defined in H.248 is installed in the MG, the event buffer function is realized by preparing an area for storing event buffer information for each termination information in the termination management table. Further, in the present invention, it is possible to support the function without mounting the FIFO (First In First Out) buffer necessary for the MG related to the present invention described above, and the mounting can be easily performed. it can. Furthermore, in the present invention, the memory usage can be reduced, so that resources can be effectively used.

  For an event that occurs during session disconnection, a notify is created by searching for a termination having event buffer information after the session is established. In the present invention, since the search condition is only termination, the search scale is reduced and the search process can be speeded up.

  Further, in the present invention, after the session is disconnected due to a communication abnormality between the MGC and the MG or a failure of the MGC, the communication state is restored, and when the session is reestablished, the MG autonomously enters the event buffer. By sequentially transmitting existing events using “notify”, it is possible to transmit the event to the MGC without missing the event that occurred during the session disconnection.

  Furthermore, in the present invention, an event is notified by sending a notify regardless of whether the MGC is compatible with an event buffer descriptor (Event Buffer Descriptor). For this reason, in the present invention, even when the MGC does not support the event buffer descriptor and the protocol version does not match, or even when the MG performs event notification for a plurality of MGCs with different protocol versions, event transmission is possible. Is possible.

  As described above, the present invention increases the call information handled by increasing the number of subscribers accommodated in the event buffer function (event monitoring function) used to monitor the service level such as call quality for the MG. It can also be implemented in an MG that assumes large-scale subscriber accommodation.

  FIG. 2 is a block diagram showing an example of a network configuration according to the embodiment of the present invention. In FIG. 2, the network according to the embodiment of the present invention includes MG1, SIP clients 2 and 3, MGC4, and networks 100, 200, and 300.

  MG1 is a system that is the subject of the present invention. A packet including call information such as 248 termination information is received. The SIP clients 2 and 3 can be connected via the networks 100 and 200 and MG1.

  FIG. 3 is a block diagram showing a configuration example of MG1 of FIG. In FIG. 3, the MG 1 includes an SBC 10 including an MGC transmission / reception unit 11, a call information management unit 12, and a packet transfer unit 13. The call information management unit 12 includes a termination registration unit 121, a termination management table 122, and an event transmission control unit 123.

  The termination information received by the MG 1 from the MGC 4 is transferred to the MGC transmission / reception unit 11. The MGC transmission / reception unit 11 converts the transferred termination information into a format for internal communication and transmits it to the call information management unit 12. The call information management unit 12 registers the transmitted call information in the termination management table 122 via the termination registration unit 121.

  When the packet flow is received from the network 100 or the network 200, the packet transfer unit 13 searches the call information management unit 12 to determine whether it matches the set call information. The set processing is performed, and the data is transferred to the opposite network 200 or network 100. If there is no matching termination information, the packet transfer unit 13 discards the packet flow.

  FIG. 4 is a diagram showing a detailed configuration of the termination management table 122 of FIG. In FIG. 4, the termination management table 122 includes termination information (“Termination A”, “Termination B”, “Termination C”, “Termination D”, “Termination E”, “Termination F”, “Termination G”), event descriptor (Event Descriptor) information ( “EventA”, “EventB”, “none”, “EventD”, “EventE”, “none”, “EventA”), event buffer information (“none”, “Event BufferB”, “Event BufferC”, “none”) , “Event Buffer E”, “none”, “none”).

  The event buffer information includes a request ID corresponding to the event descriptor information, an event ID indicating the event type, a stream ID identifying the packet flow, an event parameter indicating the event information (Event Param), and an occurrence time. It consists of a time stamp (Time Stamp).

  Here, as in “Termination A” in FIG. 4, event descriptor information is set for the termination, and when an event occurs in the corresponding termination, the packet transfer unit 13 notifies the call information management unit 12 of the event occurrence. .

  When the call information management unit 12 receives the event occurrence notification, the event occurrence notification is transferred to the event transmission control unit 123. The event transmission control unit 123 confirms the service state of the MG1 device main body, and if the device state is in service, searches for the termination to be processed. The event transmission control unit 123 discards the notified event if the apparatus state is out of service.

  If the device status is in-service and there is a termination to be processed, information is added to the event buffer item of the termination information. At this time, if the same event (the event ID and the stream ID match) already exists in the event buffer, the original data is prioritized and the newly generated event is discarded.

  After the event buffer information shown above is added to the event buffer item of the termination management table 122, if the service state of the device is in service, a notification is created from the event buffer information and transmitted.

  FIG. 5 is a flowchart showing an operation when an event occurs in the embodiment of the present invention. With reference to FIG. 2 to FIG. 5, the operation when an event occurs in the embodiment of the present invention will be described.

  When an event occurs in the termination for which event descriptor information is set as in “Termination A” in FIG. 4, the call information management unit 12 performs event detection (step S1 in FIG. 5), and then checks the device status. This is performed (step S2 in FIG. 5).

  The call information management unit 12 discards the event when the device state is NG due to failure or out of service (step S3 in FIG. 5). The call information management unit 12 searches the termination management table 122 when the device status is OK due to in-service or the like (step S4 in FIG. 5).

  The call information management unit 12 performs a termination information search of a linear search on the termination information column of the termination management table 122 shown in FIG. 4 as to whether or not the generated event matches the set termination (FIG. 4). 5 step S5). If the call information management unit 12 does not match all the terminations, the call information management unit 12 discards the event (step S6 in FIG. 5).

  When there is a termination that matches the event that has occurred, the call information management unit 12 searches the event buffer information of the termination (step S7 in FIG. 5). As a result of the search, the call information management unit 12 has already written the event buffer information, and when the same event (the event ID and the stream ID match) exists in the event buffer, the call data management unit 12 gives priority to the original data, The newly generated event is discarded (step S8 in FIG. 5).

  As a result of the search of the event buffer information, the call information management unit 12 does not write the event buffer information as in “Termination A” in FIG. 4, and writes the event buffer information when “none” ( FIG. 5 step S9). Thereafter, the call information management unit 12 performs a notify transmission process for creating and transmitting a notify based on the information (step S10 in FIG. 5).

  Then, the call information management unit 12 deletes the event descriptor information column in FIG. 4 (deletion of event descriptor information) to indicate that the termination event has ended (step S11 in FIG. 5).

  When a modification request including event descriptor information newly included in the termination information is received, the call information management unit 12 clears the event buffer information of the corresponding termination regardless of the contents. At this time, notify is not transmitted. Also, notify is not transmitted when a termination having event buffer information is subtracted.

  When the session is reestablished after the session between MGC4 and MG1 is disconnected, the call information management unit 12 starts a timer for a certain period of time, and after the timer expires, performs a linear search for the event buffer item of the termination and performs event buffer information Is created and transmitted to MGC4.

  The event transmission control unit 123 activates a timer for a period of time from when the event buffer information is notified to be transmitted until the search processing for the next termination is performed, and after the timer expires, the termination search and notification transmission are performed. And do. In this case, it is possible to prevent MGC4 congestion by adjusting the notify transmission interval.

  FIG. 6 is a flowchart showing processing at the time of session re-establishment in the embodiment of the present invention. With reference to FIG. 2 to FIG. 4 and FIG. 6, processing at the time of session re-establishment in the embodiment of the present invention will be described.

  When call re-establishment is detected (session re-establishment detection) (step S21 in FIG. 6), the call information management unit 12 starts a timer and sets a waiting time (Wait) so that processing is not performed immediately after the apparatus is started. (Start-up timer process) (step S22 in FIG. 6).

  When the timer of the activation timer process expires, the call information management unit 12 searches the termination management table 122 (step S23 in FIG. 6). The termination information column in FIG. 4 is linearly searched (termination search) (step S24 in FIG. 6). If termination exists, event buffer information is searched (event buffer search) (step S25 in FIG. 6).

  When the event buffer information exists like “Terminaton B” in FIG. 4, the call information management unit 12 creates a notify from the event buffer information and performs a notify transmission to the MGC 4 (notify transmission process) (step in FIG. 6). S26). Thereafter, the call information management unit 12 deletes the event descriptor information (step S27 in FIG. 6).

  As a result of deleting the event descriptor information, the call information management unit 12 changes the event descriptor column to “none” in “Termination C” in FIG. 4 in the termination management table 122. Then, the call information management unit 12 activates the transmission timer and sets the time until the next termination search is performed as a wait time (transmission timer process) (step S28 in FIG. 6).

  FIG. 7 is a sequence chart showing a message sequence between MG1 and MGC4 when an event occurs in the embodiment of the present invention. With reference to FIG. 7, the message exchange between MG1 and MGC4 when an event occurs in the embodiment of the present invention will be described.

  As shown in FIG. 7, in the state where the session is normally established between MG1 and MGC4 (a1 in FIG. 7), when an event occurs in MG1 (a2 in FIG. 7), MG1 Then, an event buffer creation process is performed (a3 in FIG. 7), and notify is transmitted to MGC4 (a4 in FIG. 7). In response to the notification, MGC4 transmits a notify response to MG1 (a5 in FIG. 7).

  When a failure occurs between MGC4 and MG1 and a session disconnection occurs (a6 in FIG. 7), when an event further occurs in MG1 (a7 in FIG. 7), MG1 internally performs event buffer creation processing. Although it is implemented, notify notification is not performed (a8 in FIG. 7).

  When communication between MGC4 and MG1 is restored and the session is re-established (a9 in FIG. 7), MG1 performs an event buffer search process (a10 in FIG. 7) and sends a notification of notification of the corresponding termination. (A11 in FIG. 7). In response to the notify notification, MGC4 transmits a notify response to MG1 (a12 in FIG. 7).

  Thus, in the present embodiment, H.264 is used. The function requirements of the event buffer descriptor defined in H.248 are not used by the FIFO buffer required for the MG related to the present invention described above, but the event buffer descriptor is used for the termination management information. Development man-hours can be reduced.

  In the present embodiment, an event that occurs while the session between MGC4 and MG1 is disconnected is held, and after GS1 autonomously notifies the event to MGC4 after recovery from disconnection of the session, Event information during session disconnection can be transmitted without being missed, and the MGC 4 can detect a network failure or the like immediately after the session is established. Thus, in the present embodiment, it is possible to maintain a service level such as call quality.

  Furthermore, in the present embodiment, the event buffer descriptor in the MEGACO message is not implemented, and the event is notified by notify transmission, so the H.C. of MGC4 and MG1. The event notification can be performed even when the version of the H.248 protocol does not match, or for a plurality of MGCs having different protocol versions.

FIG. 1 is a block diagram showing a configuration example of a media gateway according to the present invention. It is a block diagram which shows an example of the network structure by embodiment of this invention. FIG. 3 is a block diagram illustrating a configuration example of a media gateway in FIG. 2. It is a figure which shows the detailed structure of the termination management table of FIG. It is a flowchart which shows the operation | movement at the time of the event generation | occurrence | production in embodiment of this invention. It is a flowchart which shows the process at the time of session re-establishment in embodiment of this invention. It is a sequence chart which shows the message sequence between the media gateway at the time of the event generation in embodiment of this invention, and a media gateway controller.

Explanation of symbols

1 Media gateway
2,3 SIP client
4 Media gateway controller
10 SBC
11 MGC transceiver
12 Call Information Management Department
13 Packet transfer unit 100, 200, 300 Network
121 Termination Registration Department
122 Termination Management Table
123 Event transmission controller

Claims (14)

  Means for storing an event state detected in a state where a session with the media gateway controller is disconnected, and a search result of an event held in a termination unit in a state where the session is re-established. Means for autonomously transmitting a message to the media gateway controller.   2. The media gateway device according to claim 1, wherein the operation policy is installed at different network boundaries, and at least protocol conversion is performed.   3. The media gateway device according to claim 2, wherein an operation policy is converted between the different networks based on termination information registered in the own device. Including a termination management table for storing the termination information;
The media gateway device according to any one of claims 1 to 3, wherein an area for storing event buffer information for each termination information is provided in the termination management table.   5. The media gateway device according to claim 4, wherein, for an event that occurs during the disconnection of the session, a termination having event buffer information is searched after the session is established to create a notify to the media gateway controller. .   After the session is disconnected, when the communication state is restored and the session is re-established, events existing in an event buffer autonomously are sequentially transmitted to the media gateway controller using the notify. The media gateway device according to claim 5.   ITU-T recommendation H.264 from the media gateway controller. The media gateway device according to any one of claims 1 to 6, wherein the media gateway device is controlled using H.248 / MEGACO.   A step of storing an event state detected by the media gateway device in a state in which the session with the media gateway controller is disconnected; and an event search process held in a termination unit in a state in which the session is re-established And sending the search result autonomously to the media gateway controller.   9. The event transmission method according to claim 8, wherein the media gateway device is installed at a network boundary having a different operation policy and performs at least protocol conversion.   The event transmission method according to claim 9, wherein the media gateway device converts an operation policy between the different networks based on termination information registered in the device itself. The media gateway device is provided with a termination management table for storing the termination information,
11. The event transmission method according to claim 8, wherein an area for storing event buffer information is provided for each termination information in the termination management table.   The media gateway device searches for a termination having event buffer information after the session is established for an event that occurs while the session is disconnected, and creates a notify to the media gateway controller. 11. The event transmission method according to 11.   After the session is disconnected, the media gateway device autonomously transmits events existing in the event buffer to the media gateway controller using the notify when the communication state is restored and the session is reestablished. The event transmission method according to claim 12, wherein:   The media gateway device receives ITU-T recommendation H.264 from the media gateway controller. 14. The event transmission method according to claim 8, wherein the event transmission method is controlled using H.248 / MEGACO.

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