A civil aviation control communication monitoring system based on ED137C standard

Abstract

The application discloses a civil aviation control communication monitoring system based on ED137C standard, which receives and analyzes or packages and sends SIP messages carrying control communication monitoring identification fields based on the ED137C standard; a complex monitoring conference bridge is constructed in a VOIP core exchange server, according to different types of monitoring requirements, media streams of corresponding monitored objects are fused, and a unidirectional stream media transmission link is established with a voice communication exchange unit of a monitoring initiator; and complex monitoring between cross-system devices is realized by means of outgoing and incoming route communication management of a VOIP relay gateway. The application is based on a set of VOIP core exchange servers, VOIP relay gateway devices, VOIP radio gateway devices, a plurality of voice communication exchange units and a plurality of network switches, is simple to lay out, and one set of devices can realize one-to-one, one-to-many, many-to-one and many-to-many control communication monitoring functions with different types of VOIP systems.

Description

TECHNICAL FIELD

[0001] The application discloses a civil aviation control communication monitoring system based on an ED137C standard. The method and system are based on the ED137C standard protocol of EUROCONTROL, realize different types of monitoring functions in a VOIP system and between VOIP systems without additional monitoring equipment and lines, and provide technical support for airport air traffic control and control training and other services. BACKGROUND

[0002] In the process of civil aviation control training and actual control application, control monitoring seats are arranged for training and supervising young assistant controllers, and checking and correcting control instructions issued by the young assistant controllers. The monitoring function of the current domestic civil aviation control voice communication system is mainly realized in a mode of analog lines, that is, the handle or physical interface of the head of the monitoring seat is connected to the communication voice of the monitored seat through bypass and line connection. This mode has good communication link stability, but is limited by the exclusivity of the physical line, has poor deployment flexibility, and does not have the ability of a single controller to monitor multiple assistant controllers.

[0003] With the continuous development of IP packet communication technology, domestic and foreign civil aviation voice communication switching systems gradually change from the traditional analog switching system to the VOIP (Voice over Internet Protocol, abbreviated as VOIP) switching system. In 2009, the foreign ERROCONTROL organization began to publish the ED137 series standards, proposed a series of requirements for the application of VOIP in civil aviation communication switching systems, and clearly specified the interaction requirements of seat communication monitoring in the ED137C standard updated in 2019. Due to the special requirements of the industry, the VOIP system of the domestic civil aviation control communication switching changes relatively late: the VCCS-3000 system installed in Dongying Shengli Airport in 2019 is the earliest known domestic voice communication switching system that applies the VOIP system; since then, domestic voice communication switching system manufacturers including Nanjing Les Electronic Equipment Co., Ltd., Beijing Equipment Technology Co., Ltd., Shenyang Dongjin Aviation Technology Co., Ltd., and other major domestic voice communication switching system manufacturers have begun to research communication switching systems based on the VOIP technology system; since 2021, North China, East China, Southwest and other major air traffic control bureaus have begun to organize technical personnel of various manufacturers and relevant regional bureaus to carry out application verification joint test work of the VOIP voice communication switching system based on the ED137 series standards, and have begun to develop domestic industry standards.

[0004] In summary, a seat monitoring method based on a unified interaction standard and compatible with VoIP switching is needed to replace the traditional analog line connection method for seat monitoring, providing support for civil aviation operations such as air traffic control training and collaborative air traffic control. To achieve this, the following key issues need to be addressed: (1) How to implement seat communication monitoring interaction based on the ED137C standard protocol using IP packet communication. (2) What streaming media processing and interaction methods should be used to implement cross-system seat communication monitoring. (3) How to implement complex seat communication monitoring functions such as "one-to-many," "many-to-one," and "many-to-many." (4) How to effectively avoid "loop monitoring" during the seat communication monitoring process and ensure its stability and reliability. Summary of the Invention

[0005] Purpose of the Invention: This invention addresses the shortcomings of existing technologies by providing a seat communication monitoring design method based on the ED137C standard protocol using IP packet communication. It can replace traditional analog line methods, automatically completing complex types of air traffic control communication monitoring functions, and providing support for air traffic control and control training operations.

[0006] This invention designs a civil aviation control communication monitoring system based on the ED137C standard. The system includes a VoIP core switching server (1), a VoIP relay gateway device (2), a VoIP radio gateway device (3), a voice communication unit (VCU) seat (4), and a network switch (5).

[0007] The VoIP core switching server (1) has dual network redundancy and primary / backup data synchronization functions, used to realize signaling control, voice switching and conference bridge processing of telephone wired channels and radio wireless channels; the VoIP core switching server (1) embeds a control communication monitoring software functional unit to realize VoIP monitoring message reception and parsing, packet assembly and transmission and monitoring conference bridge management based on the ED137C standard, wherein the monitoring messages include wired communication monitoring (G / G monitoring), wireless communication monitoring (A / G monitoring) and seat communication monitoring (monitoring);

[0008] The VoIP trunk gateway device (2) is used to implement the relay transmission of signaling messages and the proxy forwarding of voice media streams, so as to realize the connection and interaction between the local VoIP system and external system resources. For each session, the method of serial number to route mapping management is used to realize the isolation of outgoing and incoming communication messages.

[0009] The VOIP radio gateway device (3) realizes the communication interaction between the VOIP system and the remote radio station in a back-to-back manner. On the radio station side, the VOIP radio gateway device (3) performs signaling and media interaction with all external VOIP radios based on the ED137C standard protocol to obtain all radio station resources. On the VOIP system side, the VOIP radio gateway device (3) performs interaction with the VOIP core exchange server (1) by using an internal interface protocol to establish a link for the communication interaction of the radio station resources on demand.

[0010] The voice communication exchange unit (4) is used to realize the initiation and termination of the VOIP monitoring function and is the initiator and receiver of the monitoring function. The voice communication exchange unit (4) sends relevant applications to the VOIP core exchange server (1) based on an internal agreement protocol in response to the operation of the human-computer interaction interface and receives the media stream of the monitoring conference bridge from the VOIP core exchange server (1).

[0011] The network switch (5) is configured in a dual-machine stacking and same-group port aggregation manner to realize the dual-network connection of the VOIP core exchange server (1), the VOIP relay gateway device (2), the VOIP radio gateway device (3), and the voice communication exchange unit (4) and complete the redundant hot backup of the network switch (5) and the ports in the group.

[0012] The VOIP monitoring function includes the intra-system monitoring function and the cross-system monitoring function.

[0013] The intra-system monitoring function refers to the monitoring function between the voice communication exchange units VCU seats (4) registered on the VOIP core exchange server (1). For example, the VCU1-1 seat in the VOIP1 system initiates a monitoring application, and the monitored object is the VCU1-2 seat in the VOIP1 system.

[0014] The cross-system monitoring function refers to the monitoring of the voice communication exchange units VCU seats (4) registered on the VOIP core exchange server (1) to the voice communication exchange units VCU seats (4) registered on the external VOIP system. For example, the VCU1-1 seat in the VOIP1 system initiates a monitoring application, and the monitored object is the VCU2-1 seat in the VOIP2 system.

[0015] The type of the VOIP monitoring function includes one-to-one monitoring, one-to-many monitoring, many-to-one monitoring, and many-to-many monitoring.

[0016] The one-to-one monitoring refers to that the monitoring party and the monitored party are both single voice communication exchange units VCU seats (4). For example, the VCU1 seat initiates monitoring, and the monitored object is the VCU2 seat.

[0017] The pair of one-to-many monitoring refers to that the monitoring party is one voice communication unit (VCU) seat (4), and the monitored party is two or more different VCU seats (4). For example, the VCU1 seat initiates the monitoring, and the monitored objects are the VCU2, VCU3, etc. seats.

[0018] The pair of one-to-many monitoring refers to that the monitoring party is one voice communication unit (VCU) seat (4), and the monitored party is two or more different VCU seats (4). For example, the VCU1 seat initiates the monitoring, and the monitored objects are the VCU2, VCU3, etc. seats.

[0019] The pair of one-to-many monitoring refers to that the monitoring party is one voice communication unit (VCU) seat (4), and the monitored party is two or more different VCU seats (4). For example, the VCU1 seat initiates the monitoring, and the monitored objects are the VCU2, VCU3, etc. seats.

[0020] The system supports the function of chain monitoring (Monitor Chain). The monitored VCU can simultaneously serve as a new monitoring initiator and apply for a new monitoring to the VOIP core switching server (1). The chain monitoring is also called multi-level monitoring, and finally forms a node-shaped cascading chain monitoring mode.

[0021] The system supports loop detection (Loop Closure). On the basis of the chain monitoring, it is detected whether the node chain loop of the monitoring exists. If it is found that the chain loop exists, the monitoring application is rejected. If the monitoring chain loop exists, it will form a self-oscillation of the RTP flow. The handle or headset of all nodes on the monitoring link will appear a high-frequency voice, which affects the normal command and control.

[0022] The loop detection (Loop Closure) of the system is processed as follows for the two monitoring modes of the system monitoring and the system-to-system monitoring.

[0023] For the system monitoring, the VOIP core switching server (1) traverses all the monitoring conference bridges in the system, extracts the monitoring initiator and the monitored member list, forms two or more one-way monitoring node links, and performs loop detection. If all the monitoring node links do not exist in the closed loop, no processing is performed. Otherwise, if the monitoring node link exists in the closed loop, the VOIP core switching server (1) replies to the 482 LoopDetected state response to reject the last monitoring application.

[0024] For the monitoring between systems, the node of the monitoring communication link is the VOIP core exchange server (1) of each VOIP system, each node embeds the node ID information of the monitoring link in the INVITE message and the reply 200OK response message of the initiation of the monitoring application, that is, the SID List (Source ID List) field is added in the SDP (Session Description Protocol) information of the message body to share, for example, sid=voip1 voip2 voip3 voip4;

[0025] Each node of the chain monitoring maintains the SID List, when a new monitoring node is added, the initiator of the monitoring notifies the uplink monitoring node to update the SID List through the INFO message. For example, when voip4 adds a new monitoring node voip5, an INFO message is sent to notify node voip3, the sid field of the INFO message is sid=voip1 voip2 voip3 voip4 voip5; after node voip3 receives the notification message, the local SID List is updated, and then an INFO message is sent to notify node voip2, and so on.

[0026] The loop detection of the "monitoring between systems" is realized by detecting whether the SID List exists in the node closed loop. If all the monitoring node links do not exist in the closed loop, no processing is performed; otherwise, if the monitoring node link exists in the closed loop, for example, voip1→voip2→voip3→voip4→voip1, the VOIP core exchange server (1) replies to the 482LoopDetected state response to refuse the last monitoring application, for example, to refuse the application of monitoring voip1 sent by voip4.

[0027] The VOIP core exchange server (1) allocates and maintains a unique number for each voice communication exchange unit VCU seat (4) in the system, and maintains a crown number-routing table for each external VOIP system, and the VOIP core exchange server (1) performs the outgoing and incoming management of the external number of the system according to the crown number-routing table.

[0028] The system realizes the monitoring function of the communication by the following steps:

[0029] Step 1, the controller clicks the listening function button on the VCU1-1 seat interface in the voice communication unit VCU1-1 in the No.1 VOIP system VOIP1, the listening function types include wired communication listening, wireless communication listening and seat communication listening, the seat interface prompts the listening success, and the corresponding listening function button is in the green highlight state; in order to more accurately describe the steps of the listening function and the belonging system and the mutual relationship of each voice communication unit, the No.N VOIP system is set as VOIPN, N is a natural number, the No.M voice communication unit VCU seat in the No.N VOIP system is set as VCUN-M seat, M is a natural number;

[0030] Step 2, in the listening function mode, the controller selects and clicks the seat button configured on the VCU1-1 seat interface or dials the seat number through the dial pad to realize the addition of the listened member (such as VCU1-2 in the VOIP1 system, VCU2-1 in the VOIP2 system, etc.), after the addition is successful, the corresponding listened member number button on the VCU1-1 seat interface is in the listened identification state (such as the button displays a yellow outer frame);

[0031] Step 3, the listened VCU1-2 and VCU2-1 seats carry out wired communication and wireless communication, the media stream of the communication interaction enters the listening conference bridge for fusion and is then unidirectionally sent to the listened VCU1-1 seat, realizing the wired communication listening, wireless communication listening and seat communication listening functions;

[0032] Step 4, the controller clicks the listening function button on the VCU1-1 seat interface again to cancel the listening function.

[0033] Step 1 includes the following steps:

[0034] Step 1-1, the controller clicks the listening function button on the VCU1-1 seat interface, if it is a seat communication listening function, the VCU1-1 seat initiates a seat communication listening conference function application to the VOIP core switching server of the No.1 VOIP system;

[0035] Step 1-2, the VOIP core switching server of the No.1 VOIP system parses the received application message based on the osip2 protocol, extracts the related media SDP information, including the seat listening port number, the seat IP address, the media receiving and sending direction and the media encoding type;

[0036] Step 1-3, according to the information extracted from the application message, a local listening conference bridge is established, the conference data structure includes the conference type, the conference ID, the listening seat number, the conference state, the server side listening port, the seat side listening port and the listening member list; in the initial state, the listening member list is empty;

[0037] Steps 1-4: After the meeting is established, the VoIP core switching server of VoIP system 1 sends an RTP (Real-time Transport Protocol) stream unidirectionally to the VCU1-1 monitoring seat; at the same time, the VoIP core switching server of VoIP system 1 replies with a 200 OK status response to the VCU1-1 monitoring seat, and the monitoring function button on the VCU1-1 seat interface is highlighted in green.

[0038] Step 2 includes the following steps:

[0039] Step 2-1: In the seat communication monitoring mode, the controller selects to click the monitored member number button on the VCU1-1 seat interface. For VCU1-2 and VCU2-1 seats, the VCU1-1 seat initiates a request to add the monitored member to the VoIP core switching server of the No. 1 VoIP system. The message carries the conference ID, the monitored member's number, and the monitoring type.

[0040] Step 2-2: The VoIP core switching server of VoIP system 1 parses the request message, extracts the monitored member number, determines whether the monitored member is a local user, and searches the registered user list of the VoIP core switching server of VoIP system 1 to see if the monitored member number exists. If the monitored member number, i.e., the VCU2-1 seat number, is an external number, then proceed to step 2-2-1; otherwise, if the monitored member is a local user, i.e., the VCU1-2 seat number, then proceed to step 2-3.

[0041] Step 2-2-1: The VoIP core switching server of VoIP system 1 looks up the routing information of the corresponding external number according to the system prefix-routing table. The VoIP core switching server of VoIP system 1 establishes a virtual seat number VCU1-1-virtual-monitor and sends a seat communication monitoring application based on the ED137 standard to the VoIP2 system through the VoIP trunk gateway device. The subject field in the message is monitoringing, the direction in the SDP of the message body is recvonly, and the SIDList is sid=voip1.

[0042] Step 2-2-2, after receiving the seat communication monitoring application sent by VCU1-1-virtual-monitor of VOIP1 from VOIP2 through the VOIP relay gateway of VOIP2, the VOIP core exchange server of the No. 2 VOIP system extracts the monitored VCU2-1 seat number in the message, establishes a local monitoring conference bridge of VOIP2, and the conference data structure includes conference type, conference ID, monitored seat number, conference status, server-side monitoring port, seat-side monitoring port and monitoring member list; the monitoring member list adds the number of the VCU2-1 seat;

[0043] Step 2-2-3: the VOIP core exchange server of the No. 2 VOIP system replies to the seat communication monitoring application response of 200 OK of the VOIP1 system through the VOIP relay gateway device, the direction of the SDP in the message body is sendonly, and the SID List is sid=voip2, thereby establishing a one-way communication RTP stream between VCU1-1-virtual-monitor of VOIP1 and Monitor Group2 of VOIP2, and the direction is Monitor Group2 to VCU1-1-virtual-monitor;

[0044] Step 2-3, the monitoring conference bridge Monitor Group1 of the VOIP core exchange server of the No. 1 VOIP system adds the local user VCU1-2 seat and the created virtual VCU1-1-virtual-monitor seat to the monitored member list;

[0045] Step 2-4, in response to step 2-1, the VOIP core exchange server of the No. 1 VOIP system replies to the VCU1-1 seat with a 200 OK message of adding monitored members successfully.

[0046] Step 3 includes the following steps:

[0047] Step 3-1, the monitored VCU1-2 seat performs wired communication, the VOIP core exchange server of the No. 1 VOIP system creates a telephone media PM of the communication calling party and the called party, and adds the PM to a media conference Media Group for exchange, and the PM media data structure includes a server-side RTP port number and IP address, a calling or called party-side RTP port number and IP address and a communication RTP stream buffer;

[0048] Step 3-2, the VOIP core exchange server of the No. 1 VOIP system adds the PM of the monitored VCU1-2 seat to the monitoring conference bridge Monitor Group1 of VOIP1, thereby realizing the wired communication monitoring of the VCU1-2 seat;

[0049] Step 3-3, the VCU1-2 seat being monitored performs wireless communication, and the VOIP core exchange server of the No.1 VOIP system creates a VCU MD and adds a radio receiving RD unit and a radio transmitting RS unit communicating with the VCU1-2 to the VCU MD. The VCU MD, the RD unit and the RS unit are all data structures related to communication RTP stream buffering, including a server-side RTP port number and IP address, a radio transceiver-side RTP port number and IP address, and a communication RTP stream buffer;

[0050] Step 3-4, the VOIP core exchange server of the No.1 VOIP system adds the VCU MD of the VCU1-2 seat being monitored to the monitoring conference bridge Monitor Group1 of the VOIP1, so as to realize wireless communication monitoring of the VCU1-2 seat.

[0051] Step 3-5, the VCU2-1 seat being monitored performs wired communication, the VOIP core exchange server of the No.2 VOIP system adds the PM of the VCU2-1 seat being monitored to the monitoring conference bridge Monitor Group2 of the VOIP2, and the RTP stream of wired communication is unidirectionally sent to the virtual VCU1-1-virtual-monitor seat in the No.1 VOIP system through the Monitor Group2, the VOIP core exchange server of the No.1 VOIP system adds the PM of the VCU1-1-virtual-monitor to the monitoring conference bridge Monitor Group1 of the VOIP1, so as to realize wired communication monitoring of the VCU2-1 seat.

[0052] Step 3-6, the VCU2-1 seat being monitored performs wireless communication, the VOIP core exchange server of the No.2 VOIP system adds the VCU MD of the VCU2-1 seat being monitored to the monitoring conference bridge Monitor Group2 of the VOIP2, and the RTP stream of wireless communication is unidirectionally sent to the virtual VCU1-1-virtual-monitor seat in the No.1 VOIP system through the Monitor Group2, the VOIP core exchange server of the No.1 VOIP system adds the PM of the VCU1-1-virtual-monitor to the monitoring conference bridge Monitor Group1 of the VOIP1, so as to realize wireless communication monitoring of the VCU2-1 seat.

[0053] Step 4 includes the following steps:

[0054] Step 4-1, the controller clicks the monitoring function button on the VCU1-1 seat interface again, and sends a seat communication monitoring cancellation application message to the VOIP core exchange server of the No.1 VOIP system;

[0055] Step 4-2, after receiving the cancel message, the VOIP core exchange server of the VOIP system 1 traverses the monitored members of the monitoring conference bridge MonitorGroup1, and judges whether the monitored member is a local user, i.e. searches the registered user list of the VOIP core exchange server of the VOIP system 1 to determine whether the monitored member number exists, if the monitored member number, i.e. the VCU1-2 seat number, is a local number, the monitored member is removed from the list;

[0056] Step 4-3, if the traversed monitored member number, i.e. the VCU2-1 seat number, is a number outside the system, the VOIP core exchange server of the VOIP system 1 sends a monitoring cancel application message in the ED137C standard through the VOIP relay gateway device, the application source is VCU1-1-virtual-monitor, and the application destination is the VCU2-1 seat;

[0057] Step 4-4, after receiving the cancel message of the seat communication monitoring, the VOIP core exchange server of the VOIP system 2 removes the VCU2-1 seat from the monitored list of the local monitoring conference MonitorGroup2;

[0058] Step 4-5, the VOIP core exchange server of the VOIP system 2 judges whether the monitored member list of the monitoring conference MonitorGroup2 is empty, if yes, destroys the monitoring conference MonitorGroup2, and returns 200OK to the VOIP core exchange server of the VOIP system 1 in response to the application of the monitoring cancel in step 4-3;

[0059] Step 4-6, after receiving the 200OK state response of the VOIP core exchange server of the VOIP system 2, the VOIP core exchange server of the VOIP system 1 removes the VCU1-1-virtual-monitor from the monitored list of the local monitoring conference MonitorGroup1;

[0060] Step 4-7, the VOIP core exchange server of the VOIP system 1 judges whether the monitored list of the local monitoring conference MonitorGroup1 is empty, if yes, destroys the monitoring conference MonitorGroup1, and returns 200OK to the VCU1-1 seat in response to the application of the seat communication monitoring cancel in step 4-1, and the seat communication monitoring process is ended.

[0061] Beneficial effects: the application realizes the civil aviation control communication monitoring function in and between the VOIP systems by means of pure software, compared with the mode of analog line lead voice, the system deployment has better convenience, and the communication link resource has higher utilization rate. The monitoring function adapts to the needs of rich application scenarios, supports three modes of monitoring of wired communication monitoring, wireless communication monitoring and seat communication monitoring, and simultaneously supports four monitoring business modes of one-to-one, one-to-many, many-to-one and many-to-many. All types of monitoring functions meet the ED137C standard protocol, and the interface standardization of the civil aviation VOIP communication switching system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0062] The above and / or other aspects of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0063] Figure 1 The media processing schematic diagram for the VOIP wired communication monitoring of the present application.

[0064] Figure 2 The media processing schematic diagram for the VOIP wireless communication monitoring of the present application.

[0065] Figure 3 The RTP data flow chart for the monitoring function in and between the VOIP systems of the present application.

[0066] Figure 4 The signaling interaction flow chart for the seat communication monitoring function in the VOIP system of the present application.

[0067] Figure 5 The signaling interaction flow chart for the seat communication monitoring function between the VOIP systems of the present application.

[0068] Figure 6 The VOIP system composition and the related device connection schematic diagram in the system of the present application. DETAILED DESCRIPTION

[0069] The present application is the advanced service function of the civil aviation VOIP control communication switching system, and realizes the control communication monitoring function between different seats by means of software. The monitoring service is cooperatively processed in the signaling level, the service level and the media level, and the signaling, the session and the media are deeply fused around the monitoring business flow.

[0070] In the signaling level, the monitoring handshake procedure is constructed by the ED137C standard SIP (Session Initial Protocol, SIP for short) communication protocol between the VOIP systems (namely, between the VOIP relay gateways), and the network layer and the transmission layer parameters of the communication monitoring process are acquired;

[0071] At the session level, a multi-level monitoring conference bridge (Monitor Group) is built inside the VOIP core exchange server. The monitoring conference bridge data structure includes monitoring conference type, monitoring seat name, seat IP address, seat port number, conference bridge local port number, and monitored member list. The monitored member list data structure further includes monitored member wired communication media information (PM), monitored member wireless communication media information (VCUMD), and the like.

[0072] At the media level, the monitoring conference bridge merges the PM and VCUMD of the monitored members to form monitoring mixing data, and then establishes a one-way RTP stream from the Monitor Group of the monitored system to the Monitor Group of the monitoring system, and from the Monitor Group of the monitoring system to the VCU of the communication seat of the monitoring initiator, to finally realize the monitoring function of the controlled communication.

[0073] The technical scheme of the present application is to embed a software function unit of regulatory communication monitoring into a VOIP core switching server, to realize a seat monitoring function in a back-to-back mode, that is, to realize the establishment of a regulatory communication monitoring conference bridge and the creation of a monitoring link (one-way RTP stream) in the VOIP core switching server. When the VOIP core switching server receives a regulatory communication monitoring application sent by a terminal, it judges whether the monitored user is in the VOIP system or outside the VOIP system, and makes corresponding processing. If the monitored object is a member in the VOIP system, the VOIP core switching server independently collects wired communication or wireless communication media of the monitored member, and transmits them into a local monitoring conference bridge (a first-level monitoring conference bridge) for fusion processing; if the monitored object is a member outside the VOIP system, the VOIP core switching server initiates an application for regulatory communication monitoring to the VOIP system where the monitored object is located, and the application message conforms to the ED137C standard protocol, that is, the subject field of the message is "G / G monitoring", "A / G monitoring" or "monitoring", and the direction in the SDP is "recvonly" and the SID List is "sid=voip1". After the VOIP system where the monitored object is located receives the application for regulatory communication monitoring, it establishes a local monitoring conference bridge (a second-level monitoring conference bridge), collects wired communication or wireless communication media of the monitored object, transmits them into the local monitoring conference bridge (the second-level monitoring conference bridge) for fusion processing, and then returns a 200OK state response conforming to the ED137C standard protocol to the VOIP system where the monitoring initiator is located, to establish a one-way RTP stream from the second-level monitoring conference bridge to the first-level monitoring conference bridge, thereby realizing the regulatory communication monitoring function of the user outside the VOIP system.

[0074] The present application provides a VOIP communication switching system supporting a regulatory communication monitoring function, as shown in Figure 6 The system adopts a dual-redundancy star bus network architecture with a dual-network switch as a core network switching device, and is a full-digital, dual-redundancy and non-blocking communication system, which has a completely redundant configuration for transmission of control signals and audio signals.

[0075] The VOIP core switching server is the core of the VOIP communication switching system, has the functions of dual-network redundancy and master-slave data synchronization, and is used for realizing the functions of signaling control, voice switching, conference bridge processing and the like of telephone wired channels and radio wireless channels. For the function of monitoring the regulated communication, the VOIP monitoring message receiving and analyzing, packet sending and monitoring conference bridge management based on the ED137C standard are mainly realized, wherein the monitoring messages include the types of "wired communication monitoring (G / G monitoring)", "wireless communication monitoring (A / G monitoring)" and "seat communication monitoring (monitoring)" and the like.

[0076] The voice communication switching unit includes a touch display screen, a voice access box, an external loudspeaker, an audio input / output device with a PTT switch, an audio input / output device including a headset and a telephone handle, and the like, and supports the controller to complete the communication of the wired telephone and the command to the air radio. It is the initiator and receiver of the VOIP regulated communication monitoring function, sends the related application to the VOIP core switching server based on the internal agreement protocol through the man-machine interface operation of the software, and receives the media stream of the monitoring conference bridge from the VOIP core switching server.

[0077] The VOIP relay gateway mainly realizes the relay transmission of the signaling message and the proxy forwarding of the voice media stream, realizes the interconnection and intercommunication with the external IP line. For each session, the device software adopts the method of crown number-routing mapping management to realize the isolation of the outgoing and incoming messages, and the interactive protocol and process based on the ED137C standard are mainly embodied in the device software.

[0078] The network switch realizes the connection of the VOIP core switching server, the voice communication switching unit and the VOIP relay gateway and the like. The network switch adopts the configuration mode of dual-machine stacking and same-group port aggregation, is connected with the dual-network ports of each device respectively, and realizes the redundant hot standby of the network switch and the ports in the group.

[0079] The working process of the present application will be further described below in combination with Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 .

[0080] The design method realizes the seat regulated communication monitoring function based on the ED137C standard protocol in four steps.

[0081] Step one: initiating the regulated communication monitoring application

[0082] The control communication monitoring application can be divided into multiple levels of monitoring applications according to business requirements. The controller initiates the monitoring application by clicking the control communication monitoring function button on the voice communication unit interface. Taking "seat communication monitoring" as an example, as shown in Figure 4 and Figure 5 , the monitoring application process in the VOIP system is shown in Figure 4 , and the monitoring application process between VOIP systems is shown in Figure 5 . Whether it is an application within the system or between the systems, VCU1-1 first initiates a monitoring application conforming to the internal system agreement protocol to the VOIP core exchange server SERVER1 of VOIP1 ①, and the message format is the SIP hypertext protocol: the application Method is INVITE, the From field is the account "300@192.168.1.101" of VCU1-1, the To field is "conf@192.168.1.200", wherein "192.168.1.200" is the IP address of SERVER1, the Subject field of the message is "vcu_monitor", and the message body (msgbody) carries SDP information indicating the IP address, port number, supported media encoding format, and media stream direction of the VCU1-1 side RTP stream receiving and sending, wherein the media stream direction is "recvonly".

[0083] After the VOIP core exchange server SERVER1 of VOIP1 receives the monitoring application message, the fields of the monitoring application are obtained through osip2 protocol analysis, a monitoring conference bridge is established, and the ②100 Trying and ③200 OK messages are replied. The SDP information of the 200 OK message carries the media data of the monitoring conference bridge, including the IP address, port number, supported media encoding format, and media stream direction, wherein the media stream direction is "sendonly".

[0084] After VCU1-1 receives the ③200 OK response, the seat communication monitoring function button on the interface becomes a green highlighted enabled state.

[0085] Step two: Establish a multi-level control communication monitoring conference bridge

[0086] In the above steps, the VOIP1 VOIP core exchange server creates a first-level control monitoring conference bridge MonitorGroup1, wherein the list of monitored members is initially empty.

[0087] According to the control business requirements, the controller clicks the voice communication unit number button configured on the VCU1-1 interface button area, or dials the voice communication unit number through the dial pad, to send a monitored member addition application message to the VOIP core exchange server of VOIP1.

[0088] AsFigure 4 VCU1-1 sends an application ⑤ INFO message to SERVER1 to add the monitored member VCU1-2, the From field is "300@192.168.1.101", the To field is "304@192.168.1.200", and the Subject field is "monitor", wherein "304" is the voice communication unit VCU1-2 in the VOIP1 system to be monitored. The VOIP core switch server adds VCU1-2 to the monitored member list of the monitoring conference and returns a 200 OK status response message ⑥ to VCU1-1. The number key of the monitored member VCU1-2 on the VCU1-1 interface is in a monitored state (the key is displayed with a yellow outer frame). According to actual business needs, an application message ⑤ can be continuously sent to add other VCU in the system to the monitored member list of the MonitorGroup1.

[0089] As shown in Figure 5 VCU1-1 sends an application ⑤ INFO message to SERVER1 to add the monitored member VCU2-1, the From field is "300@192.168.1.101", the To field is "022304@192.168.1.200", and the Subject field is "monitor", wherein "022304" is the voice communication unit VCU2-1 in the VOIP2 system to be monitored.

[0090] As described above, the VOIP core switch server allocates and maintains a unique number for each VCU seat in the system, and maintains a prefix-number-routing table for each external VOIP system. The VOIP core switch server performs outgoing and incoming management of external numbers according to the prefix-number-routing table. In the example shown in Figure 5 The prefix-number-routing table maintained by the VOIP1 core switch for the VOIP2 system is "022-10.42.1.2", wherein "10.42.1.2" is the external IP address of the VOIP trunk gateway SIP_GW2 of the VOIP2 system. After receiving the application message ⑤, the VOIP1 system VOIP core switch server parses that the voice communication unit to be monitored is in an external system and obtains the routing address of the VOIP2 system where the monitored member is located according to the prefix-number-routing table.

[0091] The VOIP core switching server sends the monitoring application message ⑦ INVITE to the trunk gateway SIP_GW2 of the VOIP2 system through the trunk gateway SIP_GW1. The application message ⑦ conforms to the ED137C standard protocol, the From field is "300Monitor@10.42.1.1", the To field is "304@10.42.1.2", the Subject field is "monitoring", the media transceiving direction in the SDP information is "recvonly", and the SID List is "sid=voip1". The "300Monitor" is a virtual voice communication switching unit user created by the VOIP1 VOIP core switching server for the VOIP2 system, the "304" is a voice communication switching unit in the VOIP2 system, and "10.42.1.2" is the trunk gateway address of the VOIP2 system.

[0092] The trunk gateway SIP_GW2 of the VOIP2 system receives the monitoring application message and sends the ⑧ INVITE message to the VOIP core switching server SERVER2 through the out-in conversion. According to the crown number routing table mapping maintained by the VOIP core switching server SERVER2, it is obtained that "10.42.1.1" is the routing address of the VOIP1 system, and the corresponding crown number is "021". The VOIP2 VOIP core switching server establishes a secondary monitoring conference bridge MonitorGroup2, the internal structure of which includes the monitoring type, the monitoring initiator "021300Monitor", the monitoring link local port number, the IP address and the monitored member list, as shown in the following table: Figure 5 The monitored member of the secondary monitoring conference bridge MonitorGroup2 is VCU2-1. After the secondary monitoring conference bridge MonitorGroup2 is established, the VOIP core switching server SERVER2 of the VOIP2 system replies to the VOIP1 system through the VOIP trunk gateway SIP_GW2 that 200 OK, the SDP information of the message contains the IP address, the local port, the media encoding and the transceiving direction of the MonitorGroup2, wherein the media transceiving direction is "sendonly", and the SID List is "sid=voip2".

[0093] The VOIP core switching server SERVER1 of the VOIP1 receives the 200 OK state response sent by the VOIP core switching server SERVER2 of the VOIP2 through the trunk gateway SIP_GW1, adds the virtual voice communication switching unit user "300Monitor" created locally to the primary monitoring conference bridge MonitorGroup1, and replies ​200 OK to VCU1-1, responding to the ⑤INFO request to add the member of the external system being monitored.

[0094] VCU1-1 receives After receiving the 200 OK status response, the number of the member VCU2-1 being monitored is displayed on the interface as a number key identification in a monitored state (with a yellow outer frame). At this point, the regulatory communication monitoring has completed the monitoring application, response, and creation of the MonitorGroup at each level of the monitoring conference bridge. As shown in Figure 4 and as shown in the regulatory communication monitoring embodiment of Figure 5 VCU2-1 in the VOIP2 system, after the wired and wireless communication media of the VCU2-1 in the VOIP2 system enter the secondary monitoring conference bridge MonitorGroup2 in a unidirectional manner, the media streams are fused and mixed, and the mixed media streams are transmitted to the primary monitoring conference bridge MonitorGroup1 in the VOIP1 system through the unidirectional communication link between the SIP_GW1 and the SIP_GW2. The wired and wireless communication media transmitted to the VCU1-2 in a unidirectional manner are fused and mixed again, and the mixed media streams are transmitted to the handle or headset of the VCU1-1 through the unidirectional communication link between the VCU1-1 and the primary monitoring conference bridge created in step one. At this point, the controller using the voice communication switching unit VCU1-1 can monitor the wired and wireless communication voice of the VCU2-1 in the local VCU1-2 and the primary VOIP2 system, achieving the effect of regulatory monitoring.

[0095] The above steps one and two are the simplest embodiment in the multi-level regulatory communication monitoring application. According to actual business needs, multiple different types of monitored members can be added, as shown in the monitoring application example of Figure 3 VCU1-1 adds VCU1-2 and VCU1-3 in the VOIP1 system and VCU2-1 and VCU2-2 in the VOIP2 system. In addition, the monitored members VCU1-2, VCU1-3, VCU2-1, and VCU2-2, or even VCU1-1 can be monitored by other voice communication switching units, achieving the function of "multi-to-multi monitoring". The design process and method steps of the application scenario are the same as steps one and two of the present specification.

[0096] Step three: fusion of wired and wireless communication media

[0097] The above steps one and two only describe the design process and method steps of the regulatory communication monitoring from the signaling layer and the session layer. The signaling interaction is based on the SIP protocol and is completed in the initial stage of establishing communication, and does not participate in the subsequent monitoring process. The session layer stores the necessary communication parameters in the monitoring process in the form of a data structure. The specific monitoring process is implemented in the media layer.

[0098] As shown in Figure 3In the shown example, after the completion of the application for monitoring the communication, the monitoring conference bridge in the VOIP1 and VOIP2 systems is created. The wired and wireless communication media of the VCU2-1 and VCU2-2 are fused in the secondary monitoring conference bridge MonitorGroup2, and the generated mixed media stream is unidirectionally transmitted to the VCU1-1-virtual-monitor (e.g. 300Monitor in the embodiment). Figure 5 Since the VCU1-1-virtual-monitor is in the list of the monitored members of the primary monitoring conference bridge MonitorGroup1, the generated mixed media stream is further fused with the wired and wireless communication media of the VCU1-2 and VCU1-3 in the MonitorGroup1, and the generated RTP stream is unidirectionally transmitted to the handset or the headset of the VCU1-1.

[0099] As Figure 1 and as Figure 2 The processes of the media entering the monitoring conference bridge MonitorGroup in the wired and wireless communication processes are respectively described in the simplest examples. Among them Figure 1 The process of the RTP stream entering the monitoring conference bridge in the wired communication process of the VCU1-2 and VCU1-3 is described; Figure 2 The process of the RTP stream entering the monitoring conference bridge in the wireless communication process of the VCU1-2 is described.

[0100] The VCU1-2 establishes the communication handshake with the VCU1-3 through the basic SIP call flow INVITE-100TRYING-180RINGING-200OK-ACK, and the VOIP core switching server establishes the phone media PM (PM, Phone Media) for the VCU1-2 and VCU1-3. The PM data structure includes the local IP address of the VOIP core switching server, the local receiving RTP port number, the local receiving buffer RecvBuf, the local sending buffer SendBuf, the IP address of the remote VCU, and the receiving RTP port number of the remote VCU. The VOIP core switching server creates the phone conference bridge Phone Group, exchanges the PM and the joining Phone Group, and the media exchange steps of the communication process of the VCU1-2 and VCU1-3 are as follows:

[0101] Step a1: the PM1-2 (connected with the VCU1-2) of the VOIP core switching server receives the RTP data from the VCU1-2, fills and accumulates the data in the RecvBuf of the PM1-2;

[0102] Step a2: PM1-3 of VOIP core exchange server (interface with VCU1-3) receives RTP data from VCU1-3, fills into RecvBuf of PM1-3 for accumulation;

[0103] Step a3: Accumulate to 10 cycles (20ms per cycle, minimum unit of RTP flow), copy data in RecvBuf of PM1-2 to SendBuf of PM1-3, copy data in RecvBuf of PM1-3 to SendBuf of PM1-2;

[0104] Step a4: Perform gain control, speech enhancement and anti-jitter processing in SendBuf;

[0105] Step a5: Establish a timer with 20ms cycle, and send data in SendBuf of PM1-2 and PM1-3 to corresponding remote VCU (remote IP address and port number) at regular intervals.

[0106] The wired communication monitoring process is shown in Figure 1 According to the current session state of the monitored member, the corresponding PM is added to the MonitorGroup, that is, the bytes in RecvBuf and SendBuf of the PM are filled into the mixed sound buffer of the MonitorGroup for fusion mixing every 20ms.

[0107] VCU1-2 establishes a communication link with a certain radio station based on the SIP call flow INVITE-100TRYING-200OK-ACK through the radio gateway RadioGW, and the VOIP core exchange server establishes RD (Radio Dispatch) and RS (Radio Selector) structures for the radio station receiving channel and the radio station transmitting channel respectively on the RadioGW side, and establishes a VCU MD (VCU Mixing and Dispatch) structure on the VCU side. The structure data includes: server side RTP port number and IP address, radio station transceiver side RTP port number and IP address, communication RTP flow buffer, etc. The wireless communication between the VCU and the radio station is a "many-to-many" interactive mechanism, and the media transceiving process is described as follows:

[0108] Step b1: The radio station sets a certain regulatory communication frequency, receives media from the air, and sends the media to the RD receiving buffer RecvBuf corresponding to the radio station in the VOIP core exchange server through the radio gateway RadioGW;

[0109] Step b2: VOIP core exchange server detects all VCUs currently selected the receiving channel of the radio, distributes media to the VCU MD corresponding to each VCU through RD;

[0110] Step b3: VOIP core exchange server detects the media data sent by each RD in the receiving buffer RecvBuf of VCU MD, and mixes and fuses the multi-media. The fused media is sent to the corresponding VCU terminal;

[0111] Step b4: VCU clicks to select the transmitting channel of the radio, and sends the media of shouting to the sending buffer SendBuf of VCU MD through pressing PTT switch. The accumulated media stream in SendBuf is sent to the receiving buffer RecvBuf in RS structure every 20 ms;

[0112] Step b5: VOIP core exchange server detects the media stream sent by each VCU in the receiving buffer RecvBuf of RS, compares the priority of each VCU, selects the media stream sent by the VCU with the highest priority, and sends it to the radio gateway RadioGW, and then sends it to the radio through RadioGW to form the shouting to the air. The VCU interface that is not selected displays the identification information of "lower priority, PPT is preempted".

[0113] The wireless communication monitoring process is shown in Figure 2 According to the current session state of the monitored member, the corresponding VCU MD is added to MonitorGroup, that is, the bytes in the RecvBuf and SendBuf of VCU MD are filled into the mixing buffer of MonitorGroup every 20 ms to mix and fuse.

[0114] The above PM of wired communication and VCU MD of wireless communication can exist in each monitored voice communication exchange unit. The media in the receiving buffer and sending buffer of each PM and VCU MD is added to the monitoring conference bridge to mix and fuse, and the fused media is sent to the handle or headset of the monitored voice communication exchange unit to form the media-level regulated communication monitoring process.

[0115] It should be noted that, as shown in Figure 1 and as shown in Figure 2The described example is the simplest wired communication and wireless communication monitoring process. According to the needs and actual conditions of specific regulatory services, the voice communication unit VCU complex wired communication and complex wireless communication process can be monitored. Because the smallest media unit in the wired communication process is PM, and the smallest media unit in the wireless communication process is VCUMD, RS and RD. The complex wired communication process is the complex processing of PM, and the complex wireless communication process is the complex processing of VCUMD, RS and RD. The regulatory communication monitoring is the process of obtaining the smallest unit PM and VCUMD for fusion mixing, which is irrelevant to the complex wired communication and complex wireless communication process. Therefore, the monitoring method and process of complex wired communication and wireless communication services can be implemented as the examples of Figure 1 and Figure 2 .

[0116] Step four: cancel the regulatory communication monitoring function

[0117] The controller clicks the monitoring function button on the VCU1-1 seat interface again to initiate an application for canceling the monitoring function. The VOIP1 VOIP core switching server receives the cancel monitoring application and parses it through the osip2 protocol, and then traverses the monitored member list of the local first-level monitoring conference bridge MonitorGroup1.

[0118] If the monitored member is a local voice communication unit VCU, such as VCU1-2 and VCU1-3 as shown in Figure 3 , the VOIP1 VOIP core switching server SERVE1 removes the VCU1-2 and VCU1-3 members from the monitored list, and disconnects the one-way RTP stream transmission link of the monitoring conference bridge cache area and the corresponding PM and VCUMD of the VCU1-2 and VCU1-3.

[0119] If the monitored member is a user outside the system, such as Figure 3VCU2-1 and VCU2-2 of the VOIP2 system. The VOIP core switch server SERVER1 of the VOIP1 sends a BYE message to cancel the monitoring to the VOIP2 system through the VOIP trunk gateway SIP_GW1. The BYE message complies with the ED137C standard protocol, the From field is "300Monitor@10.42.1.1", the To fields are "304@10.42.1.2" and "308@10.42.1.2" respectively, and the Subject field is "monitoring". Wherein "300Monitor" is a virtual voice communication unit user created by the VOIP core switch server of the VOIP1 for the VOIP2 system, "304" is the voice communication unit VCU2-1 in the VOIP2 system, "308" is the voice communication unit VCU2-2 in the VOIP2 system, and "10.42.1.2" is the trunk gateway address of the VOIP2 system.

[0120] The VOIP core switch server SERVER2 of the VOIP2 system receives the application to cancel the monitoring of the regulated communication through the trunk gateway SIP_GW2, processes similarly to the VOIP1 system, detects that the VCU2-1 and VCU2-2 are local voice communication units, and removes the VCU2-1 and VCU2-2 from the monitored list and disconnects the unidirectional RTP stream transmission link between the conference bridge buffer and the PM and VCUMD corresponding to the VCU2-1 and VCU2-2.

[0121] The VOIP core switch server SERVER2 of the VOIP2 system detects that the monitored member list is empty and receives the application to cancel the monitoring of the conference, destroys the local secondary monitoring conference bridge MonitorGroup2, and then responds to the application to cancel the monitoring of the regulated communication of the VOIP1 system by returning 200 OK to the VOIP1 system through the SIP_GW2.

[0122] The VOIP core switch server SERVER1 of the VOIP1 system receives the 200 OK response to cancel the monitoring through the SIP_GW1, removes the virtual voice communication unit VCU1-1-virtual-monitor from the monitored member list of the primary monitoring conference bridge MonitorGroup1, and disconnects the unidirectional RTP stream transmission link between the conference bridge buffer and the PM and VCUMD corresponding to the virtual voice communication unit VCU1-1-virtual-monitor.

[0123] Finally, the VOIP core switching server SERVER1 of the VOIP1 system detects that the monitored member list is empty and receives the application of the VCU1-1 for canceling the monitoring of the conference, and destroys the local first-level monitoring conference bridge MonitorGroup1. Then, in response to the application of canceling the monitoring of the communication, the 200 OK is returned to the VCU1-1.

[0124] Up to now, the monitoring of the communication is ended, the monitored state of the VCU number button of the monitored member is canceled on the interface of the VCU1-1, and the corresponding button state is restored to the idle state.

[0125] It can be seen through the above four steps that, during the normal operation of the system, the process of the monitoring of the communication can be realized by replacing the original analog line connection mode with the IP network packet communication and the related software processing. According to the demand of the monitoring of the communication, the method and the system provided by the application can support the monitoring based on three types of services, i.e., the "wired communication monitoring", the "wireless communication monitoring" and the "seat communication monitoring". Meanwhile, the method provided by the application supports the monitoring of the communication in the VOIP system and between the VOIP systems in various modes such as "one-to-one", "one-to-many", "many-to-one" and "many-to-many", wherein the application and the response of the monitoring of the communication between the VOIP systems comply with the ED137C standard protocol. In addition, the application can also meet the monitoring demand of various complex wired / wireless monitoring processes of the communication (for example, the three-party conference, the dispatch group, the call transfer, the telephone transfer, the comparison communication, the frequency coupling, etc.). In summary, the method and the system designed by the application are simple in deployment, comprehensive in function design and standard in interface design.

[0126] In the specific implementation, the application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium can store a computer program, the computer program can run some or all steps in the application content and each embodiment of the monitoring system of the communication of the civil aviation based on the ED137C standard when executed by the data processing unit. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM) or a random access memory (RAM) and the like.

[0127] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present application can be implemented by means of a computer program and a corresponding general hardware platform. Based on such understanding, the technical solutions in the embodiments of the present application can be embodied in the form of a computer program, i.e., a software product, which can be stored in a storage medium, including a plurality of instructions for causing a device (which can be a personal computer, a server, a single-chip microcomputer, a MUU or a network device, etc.) comprising a data processing unit to execute the method described in various embodiments or some parts of the embodiments of the present application.

[0128] The present application provides a civil aviation control communication monitoring system based on ED137C standard, about VOIP control command and communication monitoring, the method and way of realizing the technical scheme are many, the above-mentioned is only the preferred design way of the present application, it should be pointed out that, for the ordinary skilled in the art, without departing from the principle of the present application, can make a number of improvements and refinements, these improvements and refinements should also be regarded as the protection scope of the present application. The components not explicitly described in the embodiments can be implemented using existing technology.

Claims

1. A civil aviation control communication monitoring system based on the ED137C standard, characterized in that, The system includes a VoIP core switching server (1), a VoIP trunk gateway device (2), a VoIP radio gateway device (3), a voice communication switching unit (VCU) seat (4), and a network switch (5); The VoIP core switching server (1) has dual network redundancy and primary / backup data synchronization functions, used to realize signaling control, voice switching and conference bridge processing of telephone wired channels and radio wireless channels; the VoIP core switching server (1) embeds a control communication monitoring software function unit to realize VoIP monitoring message reception and parsing, packet sending and monitoring conference bridge management based on the ED137C standard, wherein the monitoring messages include wired communication monitoring, wireless communication monitoring and seat communication monitoring; The VoIP trunk gateway device (2) is used to realize the relay transmission of signaling messages and the proxy forwarding of voice media streams, so as to realize the connection and interaction between the local VoIP system and external system resources. For each session, the method of serial number to route mapping management is used to realize the isolation of outgoing and incoming communication messages. The VoIP radio gateway device (3) adopts a back-to-back approach to realize the communication interaction between the VoIP system and the remote radio. On the radio side, the VoIP radio gateway device (3) interacts with all external VoIP radios based on the ED137C standard protocol to obtain all radio resources. On the VoIP system side, it interacts with the VoIP core switching server (1) using the internal interface protocol to establish a link for radio resource communication interaction as needed. The Voice Communication Switching Unit (VCU) seat (4) is used to initiate and terminate the VoIP monitoring function. It is the initiator and recipient of the monitoring function. The Voice Communication Switching Unit (VCU) seat (4) responds to the human-computer interaction interface operation, sends relevant applications to the VoIP core switching server (1) based on the internal agreed protocol, and receives media streams from the VoIP core switching server (1) monitoring the conference bridge. The network switch (5) adopts a dual-machine stacking and same-group port aggregation configuration to realize dual-network connection of VOIP core switching server (1), VOIP trunk gateway device (2), VOIP radio gateway device (3) and voice communication switching unit VCU seat (4), and complete the redundancy hot standby of network switch (5) and group ports.

2. The system according to claim 1, characterized in that, The VoIP monitoring function includes in-system monitoring and cross-system monitoring; The monitoring function within the system refers to the monitoring function between the voice communication switching unit (VCU) seats (4) registered on the VoIP core switching server (1); The cross-system monitoring function refers to the voice communication switching unit (VCU) seat (4) registered in the VoIP core switching server (1) monitoring the voice communication switching unit (VCU) seat (4) registered in the external VoIP system.

3. The system according to claim 2, characterized in that, The types of VoIP monitoring functions include one-to-one monitoring, one-to-many monitoring, many-to-one monitoring, and many-to-many monitoring; The one-to-one monitoring refers to both the monitoring party and the monitored party being a single voice communication switching unit (VCU) seat (4); The one-to-many monitoring refers to the monitoring party being the same voice communication switching unit (VCU) seat (4), and the monitored party being two or more different voice communication switching unit (VCU) seats (4); The term "many-to-one monitoring" refers to a situation where the monitoring party consists of two or more different VCU seats, while the monitored party consists of the same VCU seat. The multi-to-multi monitoring refers to the monitoring party having two or more different voice communication exchange unit (VCU) seats (4), and the monitored party also having two or more different voice communication exchange unit (VCU) seats (4).

4. The system according to claim 3, characterized in that, The system supports chained listening functionality, whereby the monitored VCU can simultaneously act as a new listening initiator and submit a new listening request to the VoIP core switching server (1). The system supports loop detection. Based on chained monitoring, it detects whether the chain of monitored nodes is closed. If a closed chain is found, the monitoring request is rejected. For the two monitoring modes—intra-system monitoring and inter-system monitoring—the loop detection processing of the system is as follows: For monitoring within the system, the VoIP core switching server (1) traverses all monitoring conference bridges within the system, extracts the list of monitoring initiators and monitored members, forms two or more unidirectional monitoring node links, and performs loop detection. If none of the monitoring node links are closed, no action is taken; otherwise, if there is a closed monitoring node link, the VoIP core switching server (1) replies with a 482 LoopDetected status response to reject the last monitoring request. For monitoring between systems, the nodes of the control communication monitoring link are the VoIP core switching servers (1) of each VoIP system. Each node embeds the node ID information of the monitoring link in the INVITE message that initiates the monitoring request and the 200 OK response message, that is, adds the SID List field to the SDP information of the message body for sharing. Each node in the chained monitoring maintains a SID List. When a new monitoring node is added, the initiator of the monitoring notifies its upstream monitoring nodes to update the SID List through INFO messages.

5. The system according to claim 4, characterized in that, The VoIP core switching server (1) assigns and maintains a unique number for each voice communication switching unit (VCU) seat (4) in the system, and maintains a prefix-routing table for each external VoIP system. The VoIP core switching server (1) manages outgoing and incoming communication of external numbers in the system according to the prefix-routing table.

6. The system according to claim 5, characterized in that, The system implements the control communication monitoring function through the following steps: Step 1: The controller clicks the monitoring function button on the seat interface of the voice communication switching unit VCU1-1 in VOIP1 of VOIP system No.

1. The monitoring function includes wired communication monitoring, wireless communication monitoring and seat communication monitoring. The seat interface will indicate that the monitoring is successful and the corresponding monitoring function button will be highlighted. Setting: The Nth VoIP system is denoted as VoIPN, where N is a natural number; the Mth Voice Communication Switching Unit (VCU) seat within the Nth VoIP system is denoted as VCUN-M seat, where M is a natural number. Step 2: In the monitoring function mode, the controller can select to click the seat button configured on the VCU1-1 seat interface or dial the seat number through the dial pad to add the monitored member. After the addition is successful, the corresponding monitored member number button on the VCU1-1 seat interface will be in the monitored status. Step 3: The monitored VCU1-2 and VCU2-1 seats conduct wired and wireless communication. The media streams of the communication interaction enter the monitoring conference bridge for fusion, and then are sent unidirectionally to the monitored VCU1-1 seat, realizing wired communication monitoring, wireless communication monitoring and seat communication monitoring functions. Step 4: The controller clicks the monitoring function button on the VCU1-1 seat interface again to cancel the monitoring function.

7. The system according to claim 6, characterized in that, Step 1 includes the following steps: Step 1-1: The controller clicks the monitoring function button on the VCU1-1 seat interface. If it is the seat communication monitoring function, the VCU1-1 seat will send a request for the seat communication monitoring conference function to the VoIP core switching server of the No. 1 VoIP system. Steps 1-2: The VoIP core switching server of VoIP system 1 parses the received application message based on the osip2 protocol and extracts the relevant media SDP information, including the seat listening port number, seat IP address, media transmission and reception direction and media encoding type. Steps 1-3: Based on the information extracted from the application message, establish a local monitoring conference bridge. The conference data structure includes conference type, conference ID, monitoring seat number, conference status, server-side monitoring port, seat-side monitoring port, and monitoring member list; initially, the monitoring member list is empty. Steps 1-4: After the meeting is established, the VoIP core switching server of VoIP system 1 sends an RTP stream unidirectionally to the VCU1-1 monitoring seat; at the same time, the VoIP core switching server of VoIP system 1 replies with a 200 OK status response to the VCU1-1 monitoring seat, and the monitoring function button on the VCU1-1 seat interface is highlighted.

8. The system according to claim 7, characterized in that, Step 2 includes the following steps: Step 2-1: In the seat communication monitoring mode, the controller selects to click the monitored member number button on the VCU1-1 seat interface. For VCU1-2 and VCU2-1 seats, the VCU1-1 seat initiates a request to add the monitored member to the VoIP core switching server of the No. 1 VoIP system. The message carries the conference ID, the monitored member's number, and the monitoring type. Step 2-2: The VoIP core switching server of VoIP system 1 parses the request message, extracts the monitored member number, determines whether the monitored member is a local user, and searches the registered user list of the VoIP core switching server of VoIP system 1 to see if the monitored member number exists. If the monitored member number, i.e., the VCU2-1 seat number, is an external number, then proceed to step 2-2-1; otherwise, if the monitored member is a local user, i.e., the VCU1-2 seat number, then proceed to step 2-3. Step 2-2-1: The VoIP core switching server of VoIP system 1 looks up the routing information of the corresponding external number according to the system prefix-routing table. The VoIP core switching server of VoIP system 1 establishes a virtual seat number VCU1-1-virtual-monitor and sends a seat communication monitoring application based on the ED137 standard to the VoIP2 system through the VoIP trunk gateway device. The subject field in the message is monitoringing, the direction in the SDP of the message body is recvonly, and the SIDList is sid=voip1. Step 2-2-2: After receiving the seat communication monitoring request from VCU1-1-virtual-monitor of VOIP1 through the VOIP trunk gateway of VOIP2, the VOIP core switching server of VOIP2 extracts the seat number of the monitored VCU2-1 from the message, establishes a local monitoring conference bridge of VOIP2, and the conference data structure includes conference type, conference ID, monitoring seat number, conference status, server-side monitoring port, seat-side monitoring port, and monitoring member list; the monitoring member list is then updated with the seat number of VCU2-1. Step 2-2-3: The VoIP core switching server of VoIP system 2 replies to the VOIP1 system with a 200 OK response to request seat communication monitoring through the VoIP trunk gateway device. The direction in the SDP of the message body is sendonly, and the SID List is sid=voip2. A one-way communication RTP flow is established between VCU1-1-virtual-monitor of VoIP1 and Monitor Group2 of VoIP2, with the direction from Monitor Group2 to VCU1-1-virtual-monitor. Steps 2-3: Monitor Group 1, the monitoring conference bridge of the VoIP core switching server of VoIP system 1, adds the local user VCU1-2 seat and the created virtual VCU1-1-virtual-monitor seat to the list of monitored members. Step 2-4, in response to step 2-1, the VoIP core switching server of VoIP system 1 replies to the VCU1-1 seat with a 200 OK message indicating that the added member has been successfully added.

9. The system according to claim 8, characterized in that, Step 3 includes the following steps: Step 3-1: The monitored VCU1-2 seats conduct wired communication. The VoIP core switching server of the No. 1 VoIP system creates a telephone media PM for the caller and the called party, and adds the PM to the Media Group for exchange. The PM media data structure includes the RTP port number and IP address on the server side, the RTP port number and IP address on the caller or called party side, and the communication RTP stream buffer. Step 3-2: The VoIP core switching server of VoIP system 1 will add the PM of the VCU1-2 seats to the monitoring conference bridge Monitor Group1 of VoIP1 to realize wired communication monitoring of VCU1-2 seats. Step 3-3: The monitored VCU1-2 seats conduct wireless communication. The VoIP core switching server of the No. 1 VoIP system creates a VCUMD and adds the radio receiving RD unit and radio transmitting RS unit that communicate with VCU1-2 to the VCUMD. The VCUMD, RD and RS units are all data structures related to the communication RTP stream buffer, including the server-side RTP port number and IP address, the radio transceiver-side RTP port number and IP address, and the communication RTP stream buffer. Steps 3-4: The VoIP core switching server of VoIP system 1 will add the VCU1-2 monitoring VCU1-2 seats to the monitoring conference bridge Monitor Group1 of VoIP1 to enable wireless communication monitoring of VCU1-2 seats. Steps 3-5: The monitored VCU2-1 seat establishes wired communication. The VoIP core switching server of VoIP system 2 adds the PM of the monitored VCU2-1 seat to the monitoring conference bridge Monitor Group2 of VoIP2. The RTP stream of the wired communication is sent unidirectionally through Monitor Group2 to the virtual VCU1-1-virtual-monitor seat in the VoIP1 system. The VoIP core switching server of VoIP system 1 adds the PM of VCU1-1-virtual-monitor to the monitoring conference bridge Monitor Group1 of VoIP1, thus realizing wired communication monitoring of the VCU2-1 seat. Steps 3-6: The monitored VCU2-1 seat conducts wireless communication. The VoIP core switching server of VoIP system 2 adds the VCU2-1 seat's VCUMD to the VoIP2 monitoring conference bridge Monitor Group2. The wireless communication RTP stream is sent unidirectionally through Monitor Group2 to the virtual VCU1-1-virtual-monitor seat in the VoIP1 system. The VoIP core switching server of VoIP system 1 adds the VCU1-1-virtual-monitor's PM to the VoIP1 monitoring conference bridge Monitor Group1, thus enabling wireless communication monitoring of the VCU2-1 seat.

10. The system according to claim 9, characterized in that, Step 4 includes the following steps: Step 4-1: The controller clicks the monitoring function button on the VCU1-1 seat interface again to send a request message to cancel seat communication monitoring to the VoIP core switching server of VoIP system No.

1. Step 4-2: After receiving the cancellation message, the VoIP core switching server of VoIP system 1 traverses the monitored members of MonitorGroup1 and determines whether the monitored member is a local user. That is, it searches the list of registered users of VoIP1 VoIP core switching server to see if the monitored member number exists. If the monitored member number, i.e., the VCU1-2 seat number, is a local number, the monitored member is removed from the list. Step 4-3: If the VCU2-1 seat number of the traversed monitoring member number is an external number of the system, then the VoIP core switching server of VoIP system No. 1 sends an ED137C standard monitoring cancellation request message through the VoIP trunk gateway device. The request source is VCU1-1-virtual-monitor, and the request destination is the VCU2-1 seat. Step 4-4: After receiving the cancellation message for seat communication monitoring, the VoIP core switching server of VoIP system No. 2 removes the VCU2-1 seat from the monitored list of the local monitoring conference MonitorGroup2. Steps 4-5: The VoIP core switching server of VoIP system 2 checks whether the list of monitored members of the monitoring conference MonitorGroup2 is empty. If it is, it destroys the monitoring conference MonitorGroup2 and responds to the request for monitoring cancellation in step 4-3 by replying with 200 OK to the VoIP core switching server of VoIP system 1. Steps 4-6: After receiving the 200 OK status response from the VoIP core switching server of VoIP system 2, the VoIP core switching server of VoIP system 1 removes VCU1-1-virtual-monitor from the monitored list of local monitoring conference MonitorGroup1. Steps 4-7: The VoIP core switching server of VoIP system 1 checks whether the monitored list of local monitoring conference MonitorGroup1 is empty. If it is, it destroys the monitoring conference MonitorGroup1 and responds to the request in step 4-1 regarding the cancellation of seat communication monitoring by replying 200 OK to seat VCU1-1. The seat communication monitoring process ends.

Images