Q.921 link testing method, system and storage medium

Abstract

The present invention belongs to the field of communication voice technology, and discloses a Q.921 link test method, system and storage medium. When the present invention tests the Q.921 link, the ISDN protocol stack uses a Q.921 entity as both the user side and the network side based on the local loopback function of the E1 port, establishes a Q.921 link inside the E1 port, obtains the Q.921 link status information and reports it to the IUA protocol stack, and the IUA protocol stack queries the Q.921 link status and feeds back to the NGN platform. The present invention can determine whether the integrated digital access gateway can work normally based on the Q.921 link status without connecting the E1 line or other equipment, thereby reducing the workload and time cost of equipment installation and cutover. The present invention writes the Q.921 link status into a table, and the IUA protocol stack directly queries the table to obtain the Q.921 link status after receiving the link query message, which can reduce the system response time and improve the link test efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of communication voice technology, and more specifically, relates to a Q.921 link testing method, system and storage medium. Background Art

[0002] With the popularization of VoIP network technology, more and more traditional voice communication equipment PBX needs to be cut over to VoIP network. Enterprises use integrated digital access gateways to connect PBX to VoIP network without changing the PBX service functions, which not only reduces enterprise costs, but also expands voice communication with VoIP users and increases the diversity of enterprise voice services.

[0003] The existing Q.921 link establishment technology of the integrated digital access gateway requires two Q.921 entities to serve as the user side and the network side respectively, resulting in the inability to establish the Q.921 link when there is no PBX or instrument connected. Therefore, when the integrated digital access gateway is currently cut over to the PBX in engineering, in order to reduce the cutover time and reduce user perception, the on-site engineering personnel usually use an instrument to test the data loopback of the E1 port to determine whether the port can work normally. If the port works normally, the PBX is cut over to the integrated digital access gateway. This method requires carrying professional instruments to the computer room, and it cannot fully verify whether the gateway equipment hardware and software can work normally. Considering the comprehensive verification and cost issues, before cutting the PBX to the integrated digital access gateway, it is urgent to solve the problem of how to reduce the installation and maintenance cost of the integrated digital access gateway, and how to conveniently, quickly and comprehensively determine whether an E1 port is working normally while reducing costs. Summary of the invention

[0004] The purpose of the present invention is to provide a Q.921 link test method, system and storage medium to reduce the installation and maintenance cost of an integrated digital access gateway, and to determine whether the gateway device can work normally without the integrated digital access gateway having to access lower-layer PBX equipment or use special instruments.

[0005] In a first aspect, the present invention provides a Q.921 link testing method, comprising:

[0006] After the ISDN protocol stack in the integrated digital access gateway receives the E1 port test command, the E1 chip in the integrated digital access gateway starts a local loopback function of an E1 port, and the ISDN protocol stack uses a Q.921 entity as both the user side and the network side based on the local loopback function of the E1 port, and establishes a Q.921 link inside the E1 port; the ISDN protocol stack obtains Q.921 link status information, and reports the Q.921 link status information to the IUA protocol stack in the integrated digital access gateway;

[0007] The IUA protocol stack receives the link query information sent by the NGN platform, queries the Q.921 link status based on the Q.921 link status information, and sends link feedback information to the NGN platform.

[0008] Preferably, the Q.921 entity sends frame information, the command / response identifier of the frame information is assigned a first value, the frame information is looped back to the Q.921 entity via the E1 chip, and after receiving the frame information, the Q.921 entity modifies the command / response identifier of the frame information to a second value, so that the Q.921 entity can process the frame information normally and complete the loopback link establishment of the Q.921 entity.

[0009] Preferably, the specific implementation method of obtaining the Q.921 link status information is:

[0010] The T200 timer is started, the Q.921 entity sends SABME frames regularly, the command / response identifier of the SABME frames is related to the network side, the SABME frames are looped back to the Q.921 entity via the E1 chip, the Q.921 entity modifies the command / response identifier of the SABME frames to be related to the user side after receiving the SABME frames, the Q.921 entity processes the received SABME frame information, returns the UA frame, the command / response identifier of the UA frame is related to the network side, the UA frame is looped back to the Q.921 entity via the E1 chip, the Q.921 entity modifies the command / response identifier of the UA frame to be related to the user side after receiving the UA frame, the Q.921 entity processes the received UA frame information, stops the T200 timer, starts the T203 timer, sends an RR frame once, starts the T200 timer, the Q.921 entity sends RR frames regularly as link heartbeats, the ISDN protocol stack updates the Q.921 link status to normal, and writes into the Q.921 link status table;

[0011] During the process of the Q.921 entity periodically sending RR frames as link heartbeats, if the RR frames are looped back to the Q.921 entity through the E1 chip, it is determined that the E1 port is working normally; if the RR frames cannot be looped back to the Q.921 entity through the E1 chip, and the T200 timer times out and sends a preset number of times, it is determined that the E1 port is working abnormally, the T203 timer is stopped, the T200 timer is started, the Q.921 entity periodically sends SABME frames, the ISDN protocol stack updates the Q.921 link status to failure, and writes it into the Q.921 link status table.

[0012] Preferably, when the Q.921 link state changes, the ISDN protocol stack reports the updated Q.921 link state to the IUA protocol stack.

[0013] Preferably, after receiving the updated Q.921 link status reported by the ISDN protocol stack, the IUA protocol stack determines the change of the Q.921 link status;

[0014] If the Q.921 link status changes from fault to normal, the IUA protocol stack sends an Establish Indication primitive message to the NGN platform;

[0015] If the Q.921 link status changes from normal to faulty, the IUA protocol stack sends a Release Indication primitive message to the NGN platform.

[0016] Preferably, after receiving the Establish Request primitive message sent by the NGN platform when querying the link status, the IUA protocol stack queries the Q.921 link status from the Q.921 link status table of the ISDN protocol stack;

[0017] If the Q.921 link status is normal, the IUA protocol stack sends an Establish Confirm primitive message to the NGN platform;

[0018] If the Q.921 link status is faulty, the IUA protocol stack sends a Release Indication primitive message to the NGN platform.

[0019] Preferably, the NGN platform sends the link query information to the IUA protocol stack;

[0020] The NGN platform receives the link feedback information, and obtains a test result of the Q.921 link based on the link feedback information.

[0021] Preferably, if the NGN platform receives an Establish Indication primitive message or an Establish Confirm primitive message sent by the IUA protocol stack, the NGN platform displays that the status of the PRI interface is normal;

[0022] If the NGN platform receives the Release Indication primitive message sent by the IUA protocol stack, the NGN platform displays the status of the PRI interface as faulty.

[0023] In a second aspect, the present invention provides a Q.921 link test system, comprising: an NGN platform and an integrated digital access gateway, wherein the integrated digital access gateway comprises an E1 chip, an ISDN protocol stack and an IUA protocol stack;

[0024] The Q.921 link test system is used to implement the steps in the above-mentioned Q.921 link test method.

[0025] In a third aspect, the present invention provides a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the steps in the above-mentioned Q.921 link testing method are implemented.

[0026] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0027] (1) The present invention enables the local loopback function of an E1 port through the E1 chip in the integrated digital access gateway. Based on the local loopback function of the E1 port, the ISDN protocol stack in the integrated digital access gateway uses a Q.921 entity as both the user side and the network side, and establishes a Q.921 link inside the E1 port. That is, the present invention implements the frame processing logic of the user side and the network side on a Q.921 entity at the same time, solves the problem of the prior art that the Q.921 link cannot be established when the PBX or other equipment instruments are not connected, reduces the installation and maintenance costs of the integrated digital access gateway, and provides a technical basis for efficient and low-cost testing of the Q.921 link. Since the present invention establishes a Q.921 link inside the E1 port, when testing the Q.921 link, the Q.921 link status can be queried through the NGN platform without connecting the E1 line or other equipment instruments to determine whether the integrated digital access gateway can work normally, and then determine whether the PBX can be cut over to the E1 port. The present invention reduces the workload and time cost of equipment installation and cutover to a certain extent. When a voice call fails, the operation and maintenance personnel can also quickly locate the faulty node through link testing. Compared with the existing technology of only reporting link failures, the present invention adds a way to query the link status, which is more intuitive and more practical.

[0028] (2) The present invention writes the Q.921 link status into a table. After receiving the link query message from the NGN platform, the IUA protocol stack directly looks up the table to obtain the Q.921 link status. Compared with the prior art that requires sending a Q.921 link establishment request (EstablishRequest primitive message) to the Q.921 entity, and the Q.921 entity needs to wait for the link establishment request (EstablishRequest primitive message) from the NGN platform before establishing the Q.921 link, the present invention can reduce the coupling degree between systems, reduce the system response time, and improve the efficiency of link testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a Q.921 link test method provided in Embodiment 1 of the present invention;

[0030] Figure 2 A flowchart of a link test status reporting message in a Q.921 link test method provided in Embodiment 1 of the present invention;

[0031] Figure 3 This is a flowchart of a link test status query message in a Q.921 link test method provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0032] First, the terms used in the present invention are explained.

[0033] NGN: Next Generation Network.

[0034] ISDN: Integrated Services Digital Network, integrated digital access gateway.

[0035] IUA: ISDN User Adaptation Layer, ISDN user adaptation layer protocol.

[0036] PRI: Primary Rate Interface, a user-network interface in ISDN.

[0037] SABME: Set Asynchronous Balanced Mode Extended, set extended asynchronous balanced mode.

[0038] UA: Unnumbered Acknowledgement, unnumbered confirmation.

[0039] RR: Receive Ready, ready to receive.

[0040] T200 timer: A timer that prevents deadlock in the data link layer data transmission process.

[0041] T203 timer: A timer in the LAPD protocol. The value of this timer indicates the maximum time that no frame can be exchanged on the LAPD link.

[0042] in service: the device is in use, which in the present invention indicates that the PRI interface status is normal.

[0043] out of service: the device is not in use, which in the present invention means that the PRI interface status is faulty.

[0044] Q.921 / Q.931 Boundary Primitive Transport (QPTM) message:

[0045] Establish Indication primitive message: that is, EST_IND primitive, used to indicate that a data link has been established on the signaling channel.

[0046] Release Indication primitive message: that is, REL_IND primitive, used to indicate the release of the data link on the signaling channel.

[0047] Establish Request primitive message: that is, EST_REQ primitive, used to request to establish a data link on the signaling channel.

[0048] Establish Confirm primitive message: that is, EST_CON primitive, used to confirm that a data link has been established on the signaling link.

[0049] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0050] Embodiment 1:

[0051] Example 1 provides a Q.921 link test method, see Figure 1 ,include:

[0052] After the ISDN protocol stack in the integrated digital access gateway receives the E1 port test command, the E1 chip in the integrated digital access gateway starts a local loopback function of an E1 port. Based on the local loopback function of the E1 port, the ISDN protocol stack uses a Q.921 entity as both the user side and the network side to establish a Q.921 link inside the E1 port; the ISDN protocol stack obtains Q.921 link status information and reports the Q.921 link status information to the IUA protocol stack in the integrated digital access gateway; the IUA protocol stack receives the link query information sent by the NGN platform, queries the Q.921 link status based on the Q.921 link status information, and sends link feedback information to the NGN platform.

[0053] The NGN platform sends the link query information to the IUA protocol stack; the NGN platform receives the link feedback information and obtains the test result of the Q.921 link based on the link feedback information. In the present invention, the integrated digital access gateway provides an E1 port test command, and the engineering maintenance personnel can use this command to implement the Q.921 link test carried by the IUA link. The key technology of this solution lies in an E1 port of the integrated digital access gateway. How to establish a Q.921 link inside this port without connecting an E1 line, and display the result on the NGN platform.

[0054] For an E1 port of an integrated digital access gateway, usually a D channel needs two Q.921 entities to serve as the user side and the network side respectively to establish a Q.921 link. The technical solution of the present invention is to implement the frame processing logic of the user side and the network side on a Q.921 entity at the same time, so as to achieve the purpose of loopback link establishment by a Q.921 entity of a D channel. The present invention enables the local loopback function of an E1 port by writing a specific register on the E1 chip, and can realize the signaling data loopback from the ISDN protocol stack inside the gateway device to the E1 port and then to the ISDN protocol stack without connecting the E1 line.

[0055] A Q.921 entity has remotetype (remote Q.921 entity type, 0 indicates the user side, 1 indicates the network side) and localtype (local Q.921 entity type, 0 indicates the user side, 1 indicates the network side) parameters. localtype is configured locally, and remotetype is obtained from the frame header command / response identifier sent by the other end. Under normal circumstances, the remotetype and localtype values ​​are different. If they are the same, the Q.921 entity does not process the received frame information.

[0056] In the present invention, when the Q.921 entity of the ISDN protocol stack sends frame information, it assigns a value related to the localtype value to the frame header command / response identifier (i.e., C / R bit, indicating whether a frame is a command frame or a response frame, abbreviated as c_r) of the sent frame. Relying on the local loopback function of the E1 chip, the frame is looped back to the Q.921 entity through the E1 chip. After receiving the frame information, the Q.921 entity changes the command / response identifier of the frame header so that the frame can be normally processed by the Q.921 entity, thereby realizing the user-side and network-side frame processing logic of the D channel on a Q.921 entity.

[0057] The following describes the user-side and network-side frame processing logics of the D channel on a Q.921 entity implemented by the present invention in conjunction with the specific assignment of the C / R bit.

[0058] Normally, on the user side, the C / R bit is 0 when sending a command frame, and the C / R bit is 1 when sending a response frame; on the network side, the opposite is true, the C / R bit is 1 when sending a command frame, and the C / R bit is 0 when sending a response frame. In the present invention, when the Q.921 entity sends a command frame as the network side, the C / R bit of the frame information is assigned a value of 1, the frame information is looped back to the Q.921 entity via the E1 chip, and the Q.921 entity modifies the C / R bit of the frame information to 0 after receiving the frame information. At this time, the frame becomes a command frame sent from the user side to the network side, and the Q.921 entity as the network side can process the frame normally. Similarly, when the Q.921 entity sends a response frame as the network side, the C / R bit is 0, the frame information is looped back to the Q.921 entity via the E1 chip, and the Q.921 entity modifies the C / R bit of the frame information to 1 after receiving the frame information. At this time, the frame becomes a response frame sent from the user side to the network side, and the Q.921 entity as the network side can process the frame normally. When the Q.921 entity acts as the user side to send and receive frames, it is similar to that when it acts as the network side. In effect, a Q.921 entity acts as the network side and the user side at the same time, thereby realizing the loopback link establishment of a Q.921 entity.

[0059] The present invention utilizes the local loopback function of the E1 port, uses a Q.921 entity as both the user side and the network side, and establishes a Q.921 link inside the E1 port, thereby solving the problem in the prior art that the Q.921 link cannot be established when no PBX or other equipment instruments are connected, reduces the installation and maintenance costs of the integrated digital access gateway, and on this basis realizes efficient and low-cost testing of the Q.921 link.

[0060] Among them, the Q.921 entity sends frame information, the command / response identifier of the frame information is assigned a first value, the frame information is looped back to the Q.921 entity through the E1 chip, and after receiving the frame information, the Q.921 entity modifies the command / response identifier of the frame information to the second value, so that the Q.921 entity can process the frame information normally and complete the loopback link establishment of the Q.921 entity.

[0061] See also Figure 2 The specific implementation method of obtaining the Q.921 link status information is as follows:

[0062] S1. Enable the E1 port, start the T200 timer, and the Q.921 entity (i.e., ISDN protocol stack) sends SABME frames regularly. As the network side, the command / response identifier (abbreviated as c_r) of the SABME frame is 1.

[0063] S2. Enter the test command to enable the local loopback function of the E1 port and the Q.921 link test function;

[0064] S3, SABME frame is looped back to the Q.921 entity via the E1 chip;

[0065] S4. The default configuration of the integrated digital access gateway is that on the network side, after receiving the SABME frame, the Q.921 entity modifies the command / response identifier of the SABME frame to 0. The Q.921 entity processes the received SABME frame information and returns the UA frame. The command / response identifier of the UA frame is 0.

[0066] S5. The UA frame is looped back to the Q.921 entity via the E1 chip;

[0067] S6. After receiving the UA frame, the Q.921 entity modifies the command / response identifier of the UA frame to 1, and the Q.921 entity processes the received UA frame information, stops the T200 timer, starts the T203 timer, sends an RR frame once, and starts the T200 timer;

[0068] S7. The Q.921 entity periodically sends RR frames as link heartbeats, and the ISDN protocol stack updates the Q.921 link status to normal and writes into the Q.921 link status table.

[0069] In the process of the Q.921 entity periodically sending RR frames as link heartbeats, if the RR frames are looped back to the Q.921 entity via the E1 chip, it is determined that the E1 port is working normally (corresponding to Figure 2 S7 in the figure); if the RR frame cannot be looped back to the Q.921 entity through the E1 chip, and the T200 timer times out for a preset number of times (for example, the T200 timer times out and sends 3 times), it is determined that the E1 port is working abnormally, the T203 timer is stopped, the T200 timer is started, the Q.921 entity sends SABME frames regularly, the ISDN protocol stack updates the Q.921 link status to failure, and writes the Q.921 link status table (corresponding to Figure 2 S8 in ).

[0070] That is, after the test function is enabled, a Q.921 entity of the ISDN protocol stack periodically sends a SABME frame as the network side, which is looped back to the Q.921 entity through the E1 chip. After receiving the SABME frame, the Q.921 entity modifies the command / response identifier of the frame to be user-side related. At this time, the ISDN protocol stack no longer discards the frame, and processes it back to the UA frame normally. The UA frame is looped back to the Q.921 entity. After receiving the UA frame, the Q.921 entity modifies the command / response identifier of the frame to be user-side related, and processes it normally, stops the T200 timer, starts the T203 timer, modifies the Q.921 link state to Established, reports the state to the IUA protocol stack, and records the state of the E1 port. The ISDN protocol stack then starts the T200 timer and periodically sends the RR frame. When an abnormal situation such as a fault occurs on the E1 port, the RR frame cannot be looped back. The ISDN protocol stack stops the T203 timer, starts the T200 timer, sends SABME frames regularly, modifies the Q.921 link status to a fault, reports the status to the IUA protocol stack and records it.

[0071] In the present invention, when the port is normal, the Q.921 link is in the Established state, and if the link establishment fails due to factors such as port failure, the Q.921 link is in the Non-Established state. The Q.921 link state is written into the Q.921 link state table.

[0072] When the Q.921 link status changes, the ISDN protocol stack reports the updated Q.921 link status to the IUA protocol stack. After receiving the updated Q.921 link status reported by the ISDN protocol stack, the IUA protocol stack determines the change of the Q.921 link status. If the Q.921 link status changes from fault to normal (i.e., from non-Established status to Established status), the IUA protocol stack sends an Establish Indication primitive message to the NGN platform; after the NGN platform receives the Establish Indication primitive message, the NGN platform displays the status of the PRI interface (i.e., primary rate interface) as normal (i.e., in service). If the Q.921 link status changes from normal to fault, the IUA protocol stack sends a Release Indication primitive message to the NGN platform; after the NGN platform receives the Release Indication primitive message, the NGN platform displays the status of the PRI interface as fault (i.e., out of service).

[0073] See also Figure 3, when the NGN platform queries the link status, the NGN platform sends an EstablishRequest primitive message to the IUA protocol stack. After receiving the Establish Request primitive message, the IUA protocol stack queries the Q.921 link status from the Q.921 link status table of the ISDN protocol stack. If the Q.921 link status is normal (i.e., Established status), the IUA protocol stack sends an Establish Confirm primitive message to the NGN platform; after the NGN platform receives the Establish Confirm primitive message, the NGN platform displays that the status of the PRI interface is normal (i.e., in service). If the Q.921 link status is faulty, the IUA protocol stack sends a ReleaseIndication primitive message to the NGN platform; after the NGN platform receives the Release Indication primitive message, the NGN platform displays that the status of the PRI interface is faulty (i.e., out of service).

[0074] In the present invention, the NGN platform sends an Establish Request primitive message to the integrated digital access gateway through SCTP (Stream Control Transmission Protocol) to request to establish a data link on the signaling channel. After receiving the request, the IUA protocol stack does not send a Q.921 Establish Request primitive message to the Q.921 protocol stack, that is, after receiving the message, the IUA protocol stack does not send the link establishment request to the ISDN protocol stack to let it perform the link establishment process and then return the result, but directly queries the link status from the Q.921 link status table of the ISDN protocol stack, and returns an Establish Confirm primitive message to the NGN platform according to whether the link status is normal. The NGN platform displays the Q.921 link status of this E1 port as normal (i.e., in service). If the status is abnormal, the NGN platform returns a Release Indication primitive message to the NGN platform, and the NGN platform displays the Q.921 link status of this E1 port as faulty (i.e., out of service). ofservice), thereby achieving loose coupling between the IUA protocol stack and the ISDN protocol stack, and quickly responding to requests from the NGN platform. After the test is completed, on the NGN platform, the engineering maintenance personnel can determine the status of the IUA link and Q.921 link by checking the status of a certain PRI interface, thereby determining whether the signaling channel is normal and whether the PBX can be cut over to the E1 port of the integrated digital access gateway.

[0075] Embodiment 2:

[0076] Embodiment 2 provides a Q.921 link test system, including: an NGN platform and an integrated digital access gateway, wherein the integrated digital access gateway includes an E1 chip, an ISDN protocol stack and an IUA protocol stack.

[0077] The E1 chip is responsible for D channel signaling data transmission, and the E1 chip loops back the frame data of the ISDN protocol stack through a local loopback function.

[0078] The ISDN protocol stack interacts with its own ISDN protocol stack through the ISDN protocol, and the ISDN protocol stack is responsible for establishing a Q.921 link and saving the link status. That is, the ISDN protocol stack relies on the local loopback function of the E1 chip to implement an internal Q.921 link of an E1 port, and feeds back the Q.921 link status to the IUA protocol stack.

[0079] The IUA protocol stack interacts with the NGN platform through the IUA protocol. The IUA protocol stack is responsible for transmitting the Q.921 primitives carried by the NGN platform through the IP network and feeding back the link test results to the NGN platform through the Q.921 primitives.

[0080] The NGN platform is used to send link query information to the IUA protocol stack, receive link feedback information from the IUA protocol stack, and obtain a test result of the Q.921 link based on the link feedback information.

[0081] In the present invention, one D channel exists in one E1 port, one Q.921 entity of the ISDN protocol stack realizes link building with itself by means of the loopback function of the E1 chip, and the result is fed back to the NGN platform through the IUA protocol, and the NGN platform displays the link status, thereby realizing the Q.921 link test of one E1 port of the integrated digital access gateway.

[0082] Specifically, the Q.921 link test system provided in Example 2 is used to implement the steps in the Q.921 link test method described in Example 1, and thus will not be described in detail. For the system functions, refer to the description of Example 1.

[0083] Embodiment 3:

[0084] Embodiment 3 provides a storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps in the Q.921 link testing method described in Embodiment 1 are implemented.

[0085] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A Q.921 link testing method, characterized in that: include: After the ISDN protocol stack in the integrated digital access gateway receives the E1 port test command, the E1 chip in the integrated digital access gateway starts a local loopback function of an E1 port, and the ISDN protocol stack uses a Q.921 entity as both the user side and the network side based on the local loopback function of the E1 port, and establishes a Q.921 link inside the E1 port; the ISDN protocol stack obtains Q.921 link status information, and reports the Q.921 link status information to the IUA protocol stack in the integrated digital access gateway; The IUA protocol stack receives the link query information sent by the NGN platform, queries the Q.921 link status based on the Q.921 link status information, and sends link feedback information to the NGN platform.

2. The Q.921 link testing method according to claim 1, characterized in that: The Q.921 entity sends frame information, and the command / response identifier of the frame information is assigned a first value. The frame information is looped back to the Q.921 entity through the E1 chip. After receiving the frame information, the Q.921 entity modifies the command / response identifier of the frame information to a second value, so that the Q.921 entity can process the frame information normally and complete the loopback link establishment of the Q.921 entity.

3. The Q.921 link testing method according to claim 1, characterized in that: The specific implementation method of obtaining the Q.921 link status information is as follows: The T200 timer is started, the Q.921 entity sends SABME frames regularly, the command / response identifier of the SABME frames is related to the network side, the SABME frames are looped back to the Q.921 entity via the E1 chip, the Q.921 entity modifies the command / response identifier of the SABME frames to be related to the user side after receiving the SABME frames, the Q.921 entity processes the received SABME frame information, returns the UA frame, the command / response identifier of the UA frame is related to the network side, the UA frame is looped back to the Q.921 entity via the E1 chip, the Q.921 entity modifies the command / response identifier of the UA frame to be related to the user side after receiving the UA frame, the Q.921 entity processes the received UA frame information, stops the T200 timer, starts the T203 timer, sends an RR frame once, starts the T200 timer, the Q.921 entity sends RR frames regularly as link heartbeats, the ISDN protocol stack updates the Q.921 link status to normal, and writes into the Q.921 link status table; During the process of the Q.921 entity periodically sending RR frames as link heartbeats, if the RR frames are looped back to the Q.921 entity through the E1 chip, it is determined that the E1 port is working normally; if the RR frames cannot be looped back to the Q.921 entity through the E1 chip, and the T200 timer times out and sends a preset number of times, it is determined that the E1 port is working abnormally, the T203 timer is stopped, the T200 timer is started, the Q.921 entity periodically sends SABME frames, the ISDN protocol stack updates the Q.921 link status to failure, and writes it into the Q.921 link status table.

4. The Q.921 link testing method according to claim 3, characterized in that: When the Q.921 link state changes, the ISDN protocol stack reports the updated Q.921 link state to the IUA protocol stack.

5. The Q.921 link testing method according to claim 4, characterized in that: After receiving the updated Q.921 link status reported by the ISDN protocol stack, the IUA protocol stack determines the change of the Q.921 link status; If the Q.921 link status changes from fault to normal, the IUA protocol stack sends an Establish Indication primitive message to the NGN platform; If the Q.921 link status changes from normal to faulty, the IUA protocol stack sends a Release Indication primitive message to the NGN platform.

6. The Q.921 link testing method according to claim 3, characterized in that: After receiving the Establish Request primitive message sent by the NGN platform when querying the link status, the IUA protocol stack queries the Q.921 link status from the Q.921 link status table of the ISDN protocol stack; If the Q.921 link status is normal, the IUA protocol stack sends an Establish Confirm primitive message to the NGN platform; If the Q.921 link status is faulty, the IUA protocol stack sends a Release Indication primitive message to the NGN platform.

7. The Q.921 link testing method according to claim 1, characterized in that: The NGN platform sends the link query information to the IUA protocol stack; The NGN platform receives the link feedback information, and obtains a test result of the Q.921 link based on the link feedback information.

8. The Q.921 link testing method according to claim 7, characterized in that: If the NGN platform receives the Establish Indication primitive message or the Establish Confirm primitive message sent by the IUA protocol stack, the NGN platform displays that the status of the PRI interface is normal; If the NGN platform receives the Release Indication primitive message sent by the IUA protocol stack, the NGN platform displays the status of the PRI interface as faulty.

9. A Q.921 link test system, characterized in that: include: NGN platform and integrated digital access gateway, wherein the integrated digital access gateway includes an E1 chip, an ISDN protocol stack and an IUA protocol stack; The Q.921 link test system is used to implement the steps in the Q.921 link test method according to any one of claims 1 to 8.

10. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by the processor, the steps in the Q.921 link testing method according to any one of claims 1 to 8 are implemented.

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