WO2007009384A1

WO2007009384A1 - A method for realizing pstn emulation service

Info

Publication number: WO2007009384A1
Application number: PCT/CN2006/001772
Authority: WO
Inventors: Youzhu Shi
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-07-21
Filing date: 2006-07-20
Publication date: 2007-01-25
Also published as: CN100550936C; CN1901571A

Abstract

A method for realizing PSTN emulation service, comprises: A, Plain Old Telephone Service(POTS) terminal is given a certain applicable service character (S1); B, PSTN service control unit initiates a triggering event subscription request corresponding to the said applicable service character of the POTS terminal, and sends the session initiate protocol(SIP) message to the POTS terminal(S2); C, SIP user agent node receives and analyzes the SIP message, then creates a subscription example of the triggering event for the POTS terminal(S3); D, SIP user agent node receives the triggering signal described by the triggering event package, and sends the SIP message to the PSTN service control unit(S4); E, PSTN service control unit analyzes the said SIP message, and triggers the applicable service character of the POTS terminal(S5). Traditional POTS terminal can also use the PSTN emulation service after the POTS terminal is connected to packet core network using SIP as call control signaling.

Description

Method for realizing public telephone exchange network simulation service

The present invention relates to the field of communications, and in particular, to a public telephone switching network (PSTN) emulation service implementation method. Background technique

At present, with the continuous maturity of packet technology, traditional telecommunication networks based on circuit switching are developing towards packet-switched broadband telecommunication networks. Many operators have prepared or have established packet telecommunication networks, although users use packet communication terminals to access packet telecommunication networks. The network is the trend of future development. In the process of building a packet telecommunication network, it is impossible for all contracted users to replace the terminal equipment uniformly. Therefore, at least the current packet telecommunication network must support the access of the traditional POTS terminal. In this way, the packet telecommunication network needs to inherit the traditional PSTN service.

We know that many applications of PSTN supplementary services are closely related to analog user signaling. For example, hotline services are triggered by off-hook signals, call waiting and three-way calling services are performed by means of flashing (speaker hook). The machine interacts and uses the service. Therefore, the call control signaling in the packet telecommunication network must support the transmission of related service information such as an off-hook signal and a flashing signal.

Generally, a traditional POTS terminal can access a packet telecom network through a certain network access node device, and the device performs translation of analog user signaling and packet signaling. Currently, the most mature commercial solution is to connect the POTS terminal to the packet telecommunication network through the user media gateway, and the H.248 protocol transmits the relevant service information of the simulated user signaling to achieve the inheritance of the traditional PSTN service by the packet telecommunication network.

On the other hand, we also know that the use of SIP as the packet telecommunications core network call control signaling is one of the current technological trends, such as ITU-T and ETSI standards for NGN, so when the traditional POTS terminal accesses When using SIP as the packet core network for call control signaling, Consider how the SIP protocol conveys information about analog user signaling.

The network logical structure of the packet core network using SIP as call control signaling is shown in Figure 1:

1. The user media conversion node provides mutual conversion of circuit voice and packet voice between the POTS terminal and the packet domain, and supports the codec function of the packet voice.

2. The SIP user proxy node is a SIP user agent (SIP UA) in which the POTS terminal accesses a packet domain in which SIP is call control signaling, and when the user media conversion node and the SIP user proxy node are different network entities, The E1 interface is a media gateway control protocol such as H.248; when the network access node and the SIP user agent node are the same network entity, the E1 interface is a custom internal interface.

3. The network access node is a network node that provides the POTS terminal with the function of registration authentication and authentication of the access packet core network, and registers the POTS terminal to different call session control units. When the POTS terminal initiates a call, the network access node Route the call to its own call session control unit. When the network ingress node and the SIP user agent node are different network entities, the E2 interface between the two is SIP; when the network access node and the SIP user agent node are the same network entity, the E2 interface is SIP or customized. Internal interface. Generally, when the user media switching node and the SIP user agent node are different network entities, the SIP user agent node and the network access node are often the same network entity.

4. The call session control unit provides functions such as call control and routing connection for registered users (including POTS terminal users) accessing the packet core network, which can trigger the call to the service control unit. The E6 interface between the two call session control units is SIP. When the call session control unit and the network access node are different network entities, the E3 interface between the two is SIP; when the call session control unit and the network access node are the same network entity, the E3 interface is SIP or customized. Internal interface.

5. The service control unit provides various service logic control functions for the registered users of the access packet core network, and is a host execution environment for various services. The PSTK service control unit is a logically controlled service for providing PTSN simulation services for POTS terminal users. control unit. When the service control unit and the call session control unit are different network entities, the E4 interface between the two is SIP; when the service control unit and the call session control unit are the same network entity, the E4 interface is a SIP or a customized internal interface. . There may be multiple service control units that handle different services. 6. The media resource control unit provides control functions such as application, application, and release of various media resources, such as tone and voice notification resources, conference resources, and collection resources, for registered users (including POTS terminal users) accessing the packet core network. Wait. When the media resource control unit and the call session control unit are different network entities, the E5 interface between the two is SIP; when the media resource control unit and the call session control unit are the same network entity, the E5 interface is SIP or customized. Internal interface.

7. The Media Gateway Control Unit provides interworking control for mutual calls between registered users (including POTS terminal users) accessing the packet core network and traditional PSTN network users, and performs translation of SIP and other call control protocols. When the media gateway control unit and the call session control unit are different network entities, the E7 interface between the two is SIP; when the media gateway control unit and the call session control list are not the same network entity, the E7 interface is SIP or customized. Internal interface.

In the NGN standard being developed by ITU-T and ETSI, the traditional PSTN service that the traditional POTS terminal is connected to the NGN and provided by the NGN is called the PSTN emulation service, that is, in the NGN, The above-mentioned hotline, call waiting, and three-party calling services are still to be provided for the accessed POTS terminal users. Since the users still use the POTS terminals, the user usage patterns of these PSTN emulation services have not changed. Therefore, as mentioned above, the SIP protocol can support the transmission of analog user signaling such as off-hook signals and flashing signals to implement these PSTN emulation services.

Although the SIP protocol itself provides the SUBSCRIBE/NOTIFY mechanism to solve this problem, the event packet carried by the SIP NOTIFY message conveys the relevant service information of the simulated user signaling, but at the same time, the above-mentioned hotline, call waiting and three-party calling and other traditional PSTN supplementary services. There is no corresponding implementation, and there is no description on how to pass the analog user signaling information. Summary of the invention

The present invention provides a public telephone switching network emulation service implementation method, which is used to solve the problem that the traditional POTS terminal existing in the prior art accesses the packet core network using SIP as the call control signaling, and the PSTN emulation service cannot be implemented well. The problem.

The method of the invention comprises: A PSTN simulation service implementation method includes the following steps:

POTS terminals are given service characteristics that can be applied;

The PSTN service control unit sends, to the SIP user agent node, the filtering rule reported by the trigger event corresponding to the applicable service feature to the SIP user agent node;

The SIP user agent node receives the trigger signal corresponding to the trigger event sent by the POTS terminal, and sends a SIP message to the PSTN service control unit according to the filtering rule, where the SIP message indicates that the POTS terminal sends a trigger signal;

The PSTN service control unit parses the SIP message and triggers the service characteristics of the POTS terminal that can be applied.

The trigger signal is an off-hook signal that simulates user signaling.

The POTS terminal is given a service that can be applied as a hotline service or a busy hosted service.

The method in which the POTS terminal is given the service characteristics that can be applied is: The POTS terminal user successfully registers the hotline service or the busy registration service.

The POTS terminal is given a service that can be used by the application service to pick up a special tone service or a voice announcement service for the POTS terminal user.

The method by which the POTS terminal is given the service characteristics that can be applied is: the POTS terminal user successfully activates the message light, or the POTS terminal user successfully registers the unconditional call forwarding or outgoing call restriction or the DND or absent or the phone lock, or the POTS terminal user Enter the arrears state, or the POTS end user becomes a Centrex user or a small customer.

The PSTN service control unit triggers the applicable service characteristics of the POTS terminal, including the following steps:

The PSTN service control unit starts a timer to monitor the POTS terminal user dialing;

If the timer expires and the POTS terminal user does not dial, the PSTN service control unit sends a REFER message to the SIP user agent node, instructing the latter to initiate a new hotline number or busy registration number for the hotline or busy registration successful registration. The SIP initial session request; or the PSTN Service Control Unit sends a REFER message to the hotline number or the busy registration number, instructing the latter to initiate a new SIP initial session request to the POTS end user. The PSTN service control unit triggers the applicable service characteristics of the POTS terminal, and further includes the following steps:

The PSTN service control unit sends a REFER message to the SIP user agent node, instructing the SIP user agent node to initiate a new SIP initial session request to the special prompt tone or the voice prompting media resource; or the PSTN service control unit to the special prompt tone or voice The prompted media resource sends a REFER message, and the media resource indicating the special prompt tone or the voice prompt initiates a new SIP initial session request to the POTS terminal user;

The new SIP session is successfully established, and the POTS terminal user listens to a special prompt tone or voice prompt. The trigger signal is a flash signal that simulates user signaling.

The service is a call waiting, or three-way call, or a conference call, or a fork call transfer, or a malicious call, or a busy callback, or a busy registration of a service.

The method in which the POTS terminal is given a service characteristic that can be applied is: the POTS terminal user successfully activates the service of the service fork or successfully registers the service of the auction fork, or the POTS terminal user is online.

The trigger signal is an on-hook signal that simulates user signaling.

The filtering rule is a subscription,

The PSTN service control unit initiates a subscription request of the trigger event to a SIP user agent node, and sends a SIP message, where the SIP message indicates, by using a header field, an event packet type of the triggered event that is subscribed;

The SIP user agent node receives a trigger signal corresponding to the trigger event sent by the POTS terminal, and sends a SIP message to the PSTN service control unit according to the subscription instance of the event packet that the POTS terminal has established, and the SIP message passes the header. The domain and the carried event packet indicate that the POTS terminal issues a trigger signal.

The method further includes the step of the PSTN service control unit canceling the subscription instance:

The POTS terminal is unassigned to the service feature that can be applied; the trigger event subscription request is sent, and the SIP message is sent to the POTS terminal, and in the header field of the SIP message, the event packet type of the subscribed trigger event is specified. Unsubscribe request ID; The SIP user agent node receives and parses the SIP message via the call session control unit, and cancels the created subscription instance for the POTS terminal.

The method, the PSTO [the service control unit periodically or irregularly refreshes the subscribed instance before the subscription instance is canceled, and re-initiates the corresponding trigger event subscription request for the service feature that can be applied by the POTS terminal.

And the PSTN service control unit initiates the subscription request of the triggering event to the SIP user agent node, where the SIP message is a SUBSCRIBE message.

The SIP user agent node receives a trigger signal corresponding to the trigger event sent by the POTS terminal, and sends a SIP message to the PSTN service control unit according to the subscription instance of the event packet that the POTS terminal has established. The SIP message is a NOTIFY message.

The event package can describe one or more trigger signals.

With the solution of the present invention, after the traditional POTS terminal accesses the packet core network using SIP as the call control signaling, the hotline, busy registration, call waiting, three-party calling, conference call, call forwarding, and malicious call can still be used. Busy callback, etc. based on the off-hook signal and the cross-fork signal

The PSTN emulation service enables users to get a good experience in business inheritance. DRAWINGS

1 is a schematic diagram of a network structure of a packet core network using SIP messages as call control signaling in the prior art;

2 is a schematic flow chart of a solution of the present invention;

3 is a schematic flowchart of Embodiment 1 of the present invention;

4 is a schematic flow chart of Embodiment 2 of the present invention. detailed description

Specific embodiments of the present invention are described below in conjunction with the drawings.

The embodiments of the present invention respectively perform related descriptions based on the implementation of the PSTN emulation service based on the off-hook signal interaction and the cross-talk signal interaction. In this solution, after the POTS terminal is given the service characteristic that can be applied, in the service application process, the service control unit sends the trigger event corresponding to the applicable service characteristic to the SIP user agent node to the SIP user agent node. And the SIP user agent node sends a SIP message indicating that the POTS terminal sends a trigger signal to the PSTN service control unit according to the filtering rule when receiving the trigger signal of the trigger event pair sent by the POTS terminal, The SIP message is parsed by the PSTN service control unit, and the service characteristics of the POTS terminal that can be applied are triggered.

In the solution of the present invention, the filtering rule for establishing the simulated user signal reporting on the SIP user agent node may be multiple. For example, the PSTN service control unit subscribes to the SIP user agent node by subscribing the simulated user signal generated by the POTS terminal to the SIP user agent. The filtering rule for the analog user signal reporting is established on the node, that is, only the POTS terminal that created the subscription instance will be reported. For example, the PSTN service control unit may describe the filtering rule in a file, and then send the file to the SIP user agent node, and the SIP user agent node matches the received simulated user signal with the filtering rule described in the file, to Decide whether to report the analog user signal. This filtering rule can be described in XML in this file.

As shown in Figure 2, the flow diagram of the scheme in which the subscription is a filtering rule is as shown in the figure, and includes the following steps:

51. A traditional ordinary telephone service (POTS) terminal is given some kind of service characteristics that can be applied. If the POTS terminal user wants to use the PSTN emulation service, it must give the POTS terminal the corresponding service characteristics that can be applied. For example, if the user wants to use the hotline, the user must first successfully register the hotline number, so that the POTS terminal has the hotline characteristic that can be applied; If the user wants to receive a new message, and then listens to the voice prompt of the new message after picking up the phone, the user must first activate the message light service to enable the POTS terminal to have the off-hook voice prompt feature that can be applied; If the user wants to use a three-party call, the user must first successfully activate the service permission of the three-party call, so that the POTS terminal has the three-party call feature that can be applied, and the like. For different PSTN emulation services, the method in which the POTS terminal is given the corresponding service characteristics that can be applied is also different and will not be described in detail herein.

52. The PSTN service control unit initiates corresponding to the service characteristics that can be applied by the POTS terminal. Triggering an event subscription request, sending a SIP message to the POTS terminal, the SIP message indicating, by the header field, an event packet type of the triggered trigger event.

In the solution of the present invention, it is required to initiate a corresponding trigger event subscription request for the service feature to which the POTS terminal can be applied, and the clearing uses a SIP SUBSCRIBE message to indicate the triggered trigger in the Event header field of the SIP SUBSCRIBE message. The event packet type of the event, such as the off-hook signal event packet, the flashing signal event packet, and the like.

53. The SIP user agent node receives the SIP message through the call session control unit and performs an analysis, and creates a subscription instance of the trigger event package for the POTS terminal.

54. The SIP user agent node receives the trigger signal described by the trigger event packet sent by the POTS terminal, and sends a SIP message to the PSTN service control unit, where the SIP message indicates that the POTS terminal sends a trigger signal by using the header field and the carried event packet. .

When a POTS terminal user uses a service characteristic that can be applied, it sends a related trigger signal, which is described by a trigger event packet in which a subscription instance has been created, such as an off-hook signal event packet describing an off-hook signal. The SIP user agent node converts to a SIP NOTIFY message and sends it to the PSTN service control unit. The SIP NOTIFY message indicates that the POTS terminal sends a trigger signal through the header field and the carried event packet.

55. The PSTN service control unit parses the SIP message and triggers a service characteristic of the POTS terminal that can be applied.

After receiving the SIP NOTIFY message, the PSTN service control unit parses the SIP NOTIFY message, and determines the POTS terminal according to the information carried in the Event header field of the SIP NOTIFY message and the event packet carried by the SIP NOTIFY message, such as an off-hook signal event packet. A corresponding trigger signal, such as an off-hook signal, is triggered to trigger the service characteristics of the POTS terminal that can be applied, and provide related services for the POTS terminal.

Embodiment 1: PSTN emulation service based on off-hook signal interaction.

Typical PSTN emulation services based on off-hook signal interactions include hotline services and busy hosting services. The definitions of these two services can be found in the general technical specifications of the telephone exchange equipment of the Ministry of Posts and Telecommunications.

The application of these two services is very similar, the difference is that the registration and revocation methods are different, below Take the hotline service as an example to describe the application flow of the PSTN emulation service and the off-hook signal event packet format.

The network access node is omitted in Figure 3. When the network access node and the SIP user agent node are different network entities, the call will go through the network into the node. It should be noted that the flowchart illustrations and texts in the present invention are merely illustrative of the key technologies of the present invention, and do not represent a complete call and service control process, nor do they exhaust all possible branch processes; The format and name of the event packet carried by the described SIP message only highlights the analog user signaling information that it must carry, and does not mean that this is the only way to describe it.

As can be seen from Figure 3, the process mainly includes the following steps:

511. The POTS terminal user picks up the phone, dials, and initiates a hotline registration request. If the Chinese national standard is defined, dial "*52*TN#", where TN is the hotline subscriber number that you want to register;

512. The SIP user agent node translates the call initiated by the POTS terminal user into a SIP message, initiates a SIP initial call request, and sends an INVITE message to the call session control unit.

513. The call session control unit triggers the INVITE message to the PSTN service control unit that processes the hotline service according to a certain manner, such as the called number prefix.

514. The PSTN service control unit performs number analysis and performs service logic control of the hotline registration. If the hotline of the POTS terminal user can be successfully registered, the corresponding hotline subscriber number TN is recorded, and the INVITE message is sent to the call session control unit. 200 OK response code;

515. The call session control unit delivers a 200 OK response code of the response INVITE message to the SIP user agent node.

516. The SIP user agent node sends an ACK acknowledgement message.

517. The call session control unit delivers an ACK acknowledgement message to the PSTN service control unit.

518. After the hotline registration is successful, the PSTN service control unit initiates a subscription request for an "off-hook signal" event of the POTS terminal user, and sends a SUBSCRIBE message to the user;

The present invention defines the "off-hook signal" event package as follows:

Signal-offliook = offhook- status-line CRLF

[off ook- account CRLF] Offhook-status-line = "Off-Hook" HCOLON offhook-statue off ook-status = "yes" I "no"

Offliook-account = "Offhook- Account" HCOLON Account-URI Account-U I = SIP-employment I SIPS-URI I absoluteURI where the off-hook signal event packet type is named signal-offhook and the event package contains two parameters Off-Hook indicates whether an off-hook signal is sent, and Offhook-Account indicates the POTS terminal identifier that sent the off-hook signal.

Therefore, in the SUBSCRIBE message, the subscribed event packet type must be indicated in the "Event" header field, indicating that the subscribed off-hook signal event packet:.

Event: signal-offhook

S19. The call session control unit delivers a SUBSCRIBE message to the SIP user agent node.

5110. The SIP user agent node receives and parses the SUBSCRIBE message, creates an "off-hook signal" subscription instance for the POTS terminal user, and returns a 200 OK response code indicating that the subscription is successful.

5111. The call session control unit delivers a 200 OK response code to the PSTN service control unit, and the PSTN service control unit receives the 200 OK response code to complete the “off-hook signal, the subscription process;

5112. The POTS terminal user uses the hotline service and picks up the phone (not dialing);

5113. The SIP user agent node receives the off-hook signal of the POTS terminal user, determines that there is a subscription instance of the "off-hook signal" of the user, and sends a NOTIFY message to the subscriber (PSTN service control unit) to notify the user to send out "off-hook signal";

According to the "off-hook signal" event packet format defined above, the "Event" header field in the NOTIFY message is set as follows:

Event: signal-offhook

The event package carried in the NOTIFY message is as follows:

Off-Hook: yes

Offhook-Account: POTS End User Number in URI format

5114. The call session control unit sends a NOTIFY message to the service control unit that processes the hotline service according to a manner, such as an event packet type signal-offhook. S115: The PSTN service control unit receives and parses the NOTIFY message, determines that the POTS terminal user has issued an "off-hook signal" subscription, and learns that the POTS terminal user initiates an off-hook operation, and the user registers the hotline service. , a timer T1 is started for the user, the timer duration is a waiting time (for example, 5 seconds) specified by the hotline service, and finally a 200 OK response code indicating that the NOTIFY message is successfully received is returned;

5116. The call session control unit delivers a 200 OK response code to the SIP user agent node, and the SIP user agent node receives the 200 O response code to complete the notification process of the “off-hook signal”;

5117. The T1 timer of the POTS terminal user on the FTSN service control unit times out, the user does not dial the call, the PSTN service control unit takes out the hotline user number TO registered by the user, and sends a REFER message to the user, so that the SIP user agent node automatically Initiating a call to the T number, and the TN number can be carried by the "Refer-To" header field in the REFER message;

5118. The call session control unit delivers a REFER message to the SIP user agent node.

5119. The SIP user agent node receives and parses the REFER message, initiates a new SIP initial call request to the TN number carried in the "refer-To" header field, and sends an INVITE message to the call session control unit, where the call session control unit receives the message. INVITE message, as a normal SIP call processing, such as processing service triggering, routing connection, etc.;

5120. The SIP user agent node sends back a 200 OK response code indicating that the REFER message is successfully received.

The S12 call session control unit delivers a 200 OK response code to the PSTN service control unit;

5122. Due to the SIP protocol, the SUBSCRIBE message indicates that the subscription instance has a limited subscription period (specified by the "Expires" header field in the SUBSCRIBE message), so that the subscription instance always exists before the POTS terminal user cancels the hotline registration, PSTN The service control unit must periodically refresh the subscription instance, that is, the PSTN service control unit periodically sends the subscription to the POTS terminal user.

SUBSCRIBE message, subscribe to its "off-hook signal" event;

5123. The call session control unit delivers a SUBSCRIBE message to the SIP user agent node.

5124. The SIP user agent node receives and parses the SUBSCRIBE message, refreshes the subscription period of the "off-hook signal" subscription instance of the POTS terminal user, and returns a 200 OK response indicating that the subscription is successful. Should be coded;

5125. The call session control unit delivers a 200 OK response code to the PSTN service control unit, and the PSTN service control unit receives the 200 OK response code to complete a refresh subscription process of the “off-hook signal”;

5126. The POTS terminal user picks up the phone, dials, and initiates a hotline cancellation request. For example, according to the Chinese national standard, "#52#"

5127. The SIP user agent node translates the call initiated by the POTS terminal user into a SIP message, initiates a SIP initial call request, and sends an INVITE message to the call session control unit.

5128. The call session control unit triggers the INVITE message to the service control unit.

S 129. The PSTN service control unit performs number analysis, performs service logic control of the hotline cancellation, and responds to the INVITE message, and sends a 200 OK response code to the call session control unit.

5130. The call session control unit delivers a 200 OK response code of the response INVITE message to the SIP user agent node.

5131. The SIP user agent node sends an ACK acknowledgement message.

5132. The call session control unit delivers an ACK acknowledgement message to the PSTN service control unit.

After the hotline is revoked successfully, the PSTN service control unit initiates an unsubscribe request for the "off-hook signal" event of the POTS terminal user, and sends a SUBSCRIBE message to the user, where the "Expires" header i or the value is 0;

5134. The call session control unit delivers a SUBSCRIBE message to the SIP user agent node.

5135. The SIP user agent node receives and parses the SUBSCRIBE message, and according to the “Expires” header field value of 0, it is determined to be an unsubscribe request, and the “off-hook signal” subscription instance of the POTS terminal user is cancelled, and the return indicates that the subscription cancellation is successful. 200 OK response code;

S136 The call session control unit delivers a 200 OK response code to the PSTN service control unit, and the PSTN service control unit receives the 200 OK response code to complete the "off-hook signal," the subscription cancellation process.

Compared with the busy registration business process and the hotline business process, the registration and revocation modes are different, that is, the trigger conditions of the PSTN service control unit to subscribe to and cancel the "off-hook signal" event are different, so the present invention does not specifically describe the busy condition. Host the simulation business process.

Embodiment 2: According to the off-hook signal interaction, the PSTN simulation service is prompted after off-hook. The two PSTN emulation services described in the foregoing Embodiment 1 directly trigger the hotline and busy registration application flow according to the off-hook signal. Besides, we know that in the traditional PSTN service, the main function of the off-hook signal is After picking up the phone, the dial-up tone is sent to the off-hook user, and the POTS terminal user has the following two possibilities in addition to the normal dial tone after picking up the phone:

1. Listen to a special dial tone or a voice announcement after picking up the phone. When the user owes money, there is a new message in the voice mailbox, the user registers the unconditional call forwarding service, the user registers the outgoing call restriction service, the user registers the DND service, the user registers the absent service, the user registers the phone lockout service, the user registers When the Centrex group user is a small user, the POTS terminal user picks up the phone and listens to a special dial tone or a voice announcement, such as "Your phone has been owed", "Your voice mailbox has a new message." "Wait, and this special dial tone can be different according to the different scenarios mentioned above, such as listening to "unfortunately, call forwarding to register special dial tone", "phone lock special dial tone", "Centrex group special dial tone," etc. .

2. Listen to the second dial tone during dialing. If the Centrex group dials the group prefix, listen to the second dial tone.

That is, when the POTS terminal has certain service characteristics, it needs to be prompted immediately after it goes off-hook or during dialing. The prompt mode is to send a special dial tone or a voice announcement, or send it twice in the dialing. Dial tone.

The following is a procedure for a Centrex group user who has registered an unconditional call forwarding service to initiate a group call. The user picks up the phone and listens to the "unconditional call forwarding registration special dial tone", dials the group prefix, and listens to the "secondary dial tone." ", dial the first number outside the group, the dial tone stops.

As shown in FIG. 4, it is a schematic flowchart of the PSTN simulation service that is performed according to the off-hook signal interaction and is prompted after the off-hook. As shown in the figure, the process mainly includes the following steps:

S21. The POTS terminal user is a Centrex group user. When the user is online, the PSTN service control unit subscribes to the group prefix dialing event and the group number first dialing event through the KPML format; as described above, the Centrex group user dials the group word. After the crown, you should listen to the second dial tone. After dialing the first digit of the group, the second dial tone stops, so you must subscribe to these two events. Among them, KPML is a key markup language described in XML language, and the PSTN service control unit initiates the POTS terminal. The user's SUBSCRIBE subscription message, the subscription event type in the message is "kpml", and the dialing scheme (out of the group prefix and the out-of-group number) that needs to be subscribed is described in the message body. The specific KPML can refer to the relevant draft in the IETF. The invention is not described in detail.

S22. The call session control unit delivers a SUBSCRIBE message.

S23. The SIP user agent node receives and parses the SUBSCRIBE message, creates a "kpml," a subscription instance of the event for the POTS terminal user, and returns a 200 O response code indicating that the subscription is successful;

524. The call session control unit delivers a 200 OK response code to the PSTN service control unit.

525. When the POTS terminal user registers the helpless call forwarding service successfully, the PSTN service control unit initiates a subscription request for the user's "off-hook signal" event, sends a SUBSCRIBE message, "off-hook signal, and the event description is as before. Said

526. The call session control unit delivers a SUBSCRIBE message.

527. The SIP user agent node receives and parses the SUBSCRIBE message, creates an “off-hook signal, a subscription instance of the event, and returns a 200 OK response code indicating that the subscription is successful for the POTS terminal user;

528. The call session control unit delivers a 200 OK response code to the PSTN service control unit.

529. The POTS terminal user picks up the phone;

5210. The SIP user agent node receives the off-hook signal of the POTS terminal user, determines that there is a subscription instance of the off-hook signal for the user, and sends a NOBFY message to the subscriber (PSTN service control unit) to notify the user. Issued "off-hook signal,,," off-hook signal, the event packet format is as described above;

5211. The call session control unit delivers a NOTIFY message.

S212. The PSTN service control unit receives and parses the NOTIFY message, and determines that the POTS terminal user has issued an "off-hook signal" subscription, and learns that the POTS terminal user initiates an off-hook operation, and returns a successful 200 OK response code. ;

5213. The call session control unit delivers a 200 OK response code.

5214. After receiving the off-hook signal of the POTS terminal user, the PSTN service control unit instructs the user to listen to the “unconditional call forwarding registration special dial tone”, and sends a REFER message to the user, so that the SIP user agent node can send the media resource control unit to the media resource control unit. Initiate a call, in the "Refer-To" header field The "method" parameter indicates the "INVITE" message, and the "unconditional call forwarding registration special dial tone" can be directly represented by the URI address in the "Refer-To" header field; or " Refer- To," in the header field only Indicates the address of the media resource control unit, and the specific played tone type "unconditional call forwarding registration special dial tone" is indicated in the message body;

S215. The call session control unit delivers a REFER message.

5216. The SIP user agent node receives and parses the REFER message, and sends back a 200 OK response code indicating that the reception is successful.

5217. The call session control unit delivers a 200 OK response code.

5218. The SIP user agent node initiates a call session request to the media resource control unit, sends a SIP INVITE message, and requests to play an “unconditional call forwarding registration special dial tone”;

5219. The call session control unit delivers an INVITE message.

5220. The media resource control unit sends back a 200 OK response response code indicating the response.

S221. The call session control unit delivers a 200 OK response response code.

5222. The SIP user agent node sends back an ACK acknowledgement message that the 200 OK response response code is successful.

5223. The call session control unit delivers an ACK acknowledgement message to the media resource control unit, the SIP session is successfully established, and the POTS terminal user listens to the “unconditional call forwarding registration special dial tone,”;

5224, the POTS terminal user then dials the Centrex out-of-group prefix, such as "0";

5225. The SIP user agent node receives the outbound prefix number dialed by the POTS terminal user, determines that there is a subscription instance of the user's "kpml", and matches the subscribed dial plan, and if the matching is successful, the subscriber (PSTN) The service control unit sends a NOTIFY message to notify the user that a "kpml" event is sent, and the message body carries the group prefix number;

5226. The call session control unit delivers a NOTIFY message.

5227. The PSTN service control unit receives and parses the NOTIFY message, determines that the POTS terminal user has subscribed to the "kpml", and receives the outbound group prefix number dialed by the POTS terminal user from the message body, and performs number analysis and judgment. The number is the out-of-group prefix and returns the 200 OK response code that was successfully received. S228. The call session control unit delivers a 200 OK response code.

The S229 PSTN service control unit first controls the media resource control unit to stop playing the "unconditional call forwarding registration special dial tone", and sends a REFER message to the SIP user agent node, which is indicated as "" in the "method" parameter of the "Refer-To" header field. BYE" message;

S230. The call session control unit delivers a REFER message.

5231. The SIP user agent node receives and parses the REFER message, and sends back a 200 OK response code indicating that the reception is successful.

5232. The call session control unit delivers a 200 OK response code.

5233. The SIP user proxy node initiates a BYE message to the media resource control unit according to the method method indicated by the REFER message, and releases a session of “unconditional call forwarding registration special dial tone”;

5234. The call session control unit delivers a BYE message.

5235. The media resource control unit releases the session of “unconditional call forwarding registration special dial tone”, and returns a 200 OK response code that is successfully released.

5236. The call session control unit delivers a 200 OK response code.

5237. The PSTN service control unit controls the media resource control unit to play a "secondary dial tone" to the user, and sends a REFER message to the SIP user agent node, indicating "INVITE" in the "method" parameter of the " Refer-To" header field. Message

S238. The call session control unit delivers a REFER message.

S239. The SIP user agent node receives and parses the REFER message, and sends back a 200 OK response code indicating that the reception is successful.

S240. The call session control unit delivers a 200 OK response code.

5241. The SIP user agent node initiates a call session request to the media resource control unit, sends a SIP INVITE message, and requests to play a “secondary dial tone”;

5242. The call session control unit delivers an INVITE message.

5243. The media resource control unit returns a 200 OK response response code indicating the response.

5244. The call session control unit delivers a 200 OK response response code. 5245. The SIP user agent node sends back an ACK acknowledgement message that the 200 OK response response code is successful.

5246. The call session control unit delivers an ACK acknowledgement message to the media resource control unit, the SIP session is successfully established, and the POTS terminal user listens to the “secondary dial tone”;

S247, the POTS terminal user then dials the first place of the group number;

S248. The SIP user agent node receives the first group number of the group dialed by the POTS terminal user, determines that there is a subscription instance of the user's "kpml", and matches the subscribed dialing plan. If the matching is successful, the subscriber (PSTTST service) The control unit sends a NOTIFY message to notify the user that a "kpml" event is sent, and the message body carries the first digit of the group number;

S249> The call session control unit transmits a NOTIFY message;

5250. The PSTN service control unit receives and parses the JTIFY message, determines that the POTS terminal user has subscribed to the "kpml", receives the first group external number dialed by the POTS terminal user from the message body, and returns a successful receiving 200. OK response code;

5251. The call session control unit delivers a 200 OK response code.

S252. The PSTN service control unit first controls the media resource control unit to stop playing the "secondary dial tone", and sends a REFER message to the SIP user agent node, indicating the message "BYE" in the "method" parameter of the " Refer-To" header field. ;

S253. The call session control unit delivers a REFER message.

5254. The SIP user agent node receives and parses the REFER message, and sends back a 200 OK response code indicating that the reception is successful.

5255. The call session control unit delivers a 200 OK response code.

5256. The SIP user agent node initiates a BYE message to the media resource control unit according to the method method indicated by the REFER message, and releases the session of the second tone.

5257. The call session control unit delivers a BYE message.

5258. The media resource control unit releases the "secondary dial tone," session, and returns a 200 OK response code that is successfully released.

5259. The call session control unit delivers a 200 OK response code. Embodiment 3: PSTN emulation service based on the cross-signal signal interaction.

Typical PSTN emulation services based on the cross-talk signal interaction are: call waiting, three-way calling, conference call, call forwarding, finding malicious calls, busy callback, busy registration, etc. The definition of the service can be found in the telephone exchange equipment of the Ministry of Posts and Telecommunications. General technical specification. There are three specific ways in which the flash signal can interact in these services:

1. After the flash is shot, dial a specific service code to activate a service registration, such as busy callback and busy registration.

2. After the fork is shot, dial a specific number or service code to activate a service application mode, such as call waiting, three-party calling, and finding a malicious call.

3. After the flash is shot, dial a called subscriber number to initiate a new call, such as three-way calling, conference call, and call forwarding.

It can be seen that no matter which PST emulation service is implemented correctly, the SIP user agent node must pass the scramble signal to the PSTN service control unit through the event packet carried by the NOTIFY message. According to the SUBSCRIBE/NOTIFY mechanism of SIP, before this, the PSTN service control unit must first subscribe to the SIP user agent node for the "cross-signal" event of the POTS terminal user.

In the aforementioned hotline service flow, after the registration hotline is successful, the user needs to "off-hook signal, and report it to the PSTN service control unit (the ordinary user does not need to do this processing), so the user can register according to the service code. And revocation as the trigger condition for the "off-hook signal" event subscription and unsubscribe, but for the simulation service based on the cross-signal interaction, as long as the user can shoot the fork, the "cross-signal signal" needs to be reported to the PSTN. The business control unit, therefore, the trigger conditions for the "cross-signal" event subscription and unsubscribe can be as follows:

1. POTS terminal users are online and offline in the packet domain, as a trigger condition for subscription and unsubscription of the "cross-signal" event. Online and offline include: user registration and logout, system occlusion and occlusion of the user.

2. When the POTS terminal user activates or cancels the service authority of the above-mentioned one service, it is a trigger condition for the subscription and unsubscription of the "cross-fork signal" event.

Regardless of the trigger condition of the method, the PSTN service control unit uses the SUBSCRIBE message. The process of subscribing and unsubscribing to the "cross-signal" event of the POTS end user is the same.

Since the PSTN service control unit subscribes and unsubscribes (including refresh subscriptions) to the POTS end user's "cross-signal" event, and the SIP user agent node pairs the "flash signal, the notification of the event, and the aforementioned "off-hook signal," The process is similar, and the process is no longer described in the present invention.

The present invention defines a "cross-over signal" event package as follows:

Signal-flashhook = flash-status-line CRLF

[flash-account CRLF]

Flash-status-line = "Flash-Hook" HCOLON flash-status flash-status - "yes" I "no"

Flash-account = "Flash-Account" HCOLON Account-U I Account-U I = SIP-URI I SIPS-URI / absoluteURI

Among them, the flashing signal event packet type is named signal-flashhook, and the event packet contains two parameters. Flash-Hook indicates whether the flashing signal is sent, and Flash-Account indicates the POTS terminal identifier that sends the flashing signal.

Wherein, the PSTN service control unit uses the SUBSCRIBE message to subscribe and unsubscribe the "cross-signal" event of the POTS terminal user, and must indicate the subscribed event packet type in the "Event" header field of the SUBSCRIBE message, indicating that the subscription cross-signal signal Event package:

Event: signal-flashhook

When the POTS terminal user uses the above service, the SIP user agent node receives the flashing signal of the POTS terminal user, and determines that there is a subscription instance of the "flash signal" of the user, and then the subscriber service control unit) Send a NOTIFY message, informing the user that a "flash signal" has been issued, in the "off-hook signal" event packet format defined above, the "Event" header field in the NOTIFY message:

Event: signal-flashhook

The event package carried in the NOTIFY message is as follows:

Flash-Hook: yes

Flash-Account: POTS end user number in URI format

The number dialed by the POTS terminal user after the call is also reported to the PSTN service control unit by the SIP user agent node. It can also be carried by the NOTIFY message. For details, see the IETF current grass. The draft-ietf-sipping-kpml-07.txt, the PSTN service control unit receives the number dialed by the user after the flashing of the fork, performs number analysis and performs corresponding business logic control, and the process is not described in detail in the present invention.

In addition, according to the foregoing three embodiments, it can be seen that the off-hook signal and the flashing signal are very similar two kinds of analog user signaling, which are analog user signaling caused by the operation of the hook of the dialogue machine, and therefore, their events The package can be defined as a hook signal event package. The event package is defined as follows: signal-hook = hook-status-line CRLF

[flash-account CRLF]

Hook-status-line = "Hook-Type" HCOLON hook-status hook-status = "off-hook" I "flash-hook" I "no" hook-account = "Hook-Account" HCOLON Account-URI Account-URI = SIP-U II SIPS-URI / absolute

Among them, the hook signal packet type is named signal-hook, and the event packet contains two parameters Hook-Type indicating the hook operation category, and the off-hook category and the fork type are respectively off-hook and flash- Hook, Hook-Account indicates the POTS terminal identifier that issues the corresponding hook operation.

When the PSTN service control unit uses the SUBSCRIBE message to subscribe and unsubscribe the "cross-signal," and "off-hook" events of the POTS end user, the subscribed event packet type must be indicated in the "Event" header field of the SUBSCRIBE message. Subscribe to the Hook Signal Event Package:

Event: signal-hook

When the SIP user agent node receives the flashing signal of the POTS terminal user and determines that there is a subscription instance of the "flash signal" of the user, it sends a NOTIFY message to the subscriber (PSTN service control unit), notifying the user that the message is sent. "Crossing the signal", the "Event" header field in the NOTIFY message:

Event: signal-hook

The event package carried in the NOTIFY message is as follows:

Hook-Type: flash-hook

Hook-Account: POTS end user number in URI format When the SIP user agent node receives the off-hook signal of the POTS terminal user and determines that there is a subscription instance of the "off-hook signal" of the user, the subscriber sends a NOTIFY message to the subscriber (PST service control unit), notifying the user that the user has sent the "Off-hook signal", the "Event" header field in the NOTIFY message:

Event: signal-hook

The event package carried in the NOTIFY message is as follows:

Hook-Type: off-hook

Hook-Account: POTS end user number in URI format

As can be seen from the description of the above three embodiments, after the traditional POTS terminal accesses the packet core network using SIP as call control signaling, the hotline, busy registration, call waiting, and three parties can still be used. Calls, conference calls, call forwarding, malicious calls, busy callbacks, etc., based on off-hook signals, and cross-signal interaction simulation services, so that users get a good experience in business inheritance.

It can be seen that the core idea of the present invention is to implement an off-hook signal and a bifurcation signal generated by a SIP user agent node in order to implement a PSTN emulation service triggered by an analog user signal (off-hook signal, bifurcation signal). The SIP message is delivered to the service control unit for subsequent service processing. At the same time, because the PSTN service control unit only needs to process the related simulation service, the SIP user agent node is required to report the simulated user signal generated by the POTS terminal, that is, the SIP user agent node needs to selectively report according to a certain filtering rule (instead of In any of the foregoing embodiments, the PSTN service control unit establishes a filtering rule for simulating user signal reporting on the SIP user agent node by subscribing to the SIP user agent node an analog user signal generated by the POTS terminal. Only the POTS terminal that created the subscription instance will be reported for the simulated user signal.

Obviously, the PSTN service control unit can also establish a filtering rule for the simulated user signal reporting on the SIP user agent node by other means. For example, the PSTN service control unit can describe the filtering rule in a file, and then send the file to the SIP user. The proxy node, the SIP user proxy node matches the received simulated user signal with the filtering rules described in the file to determine whether The analog user signal is reported. This filtering rule can be described in XML in this file. At this time, the analog user signal may still be in the event packet description format in the foregoing embodiment, and may still be reported by the SIP NOTIFY message, or may be reported by the SIP PUBLISH advertisement message; of course, since the filtering rule has changed at this time Therefore, it is also possible to carry analog user signals in other description formats through other SIP messages. '

In addition, the analog user signal that needs to be reported to the network has an on-hook signal in addition to the off-hook signal and the flash signal. The present invention is also applicable to the scenario where the SIP user agent node reports the on-hook signal to the PST service control unit due to the implementation of the simulation service. . For example, in general, after the POTS terminal hangs up, the SIP user agent node will directly send a SIP BYE goodbye message to the network to release the call. In the implementation process of some emulation services, only the SIP user agent node is required to report the on-hook signal, but The call is not released, and the method provided by the present invention can be employed at this time. The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

Rights request

A method for implementing a PSTN simulation service, comprising the steps of:

The POTS terminal is given a service characteristic that can be applied; the filtering rule reported by the trigger event corresponding to the service characteristic of the application;

2. The method according to claim 1, wherein the trigger signal is an off-hook signal simulating user signaling.

The method according to claim 2, wherein the POTS terminal is given a service that can be applied as a hotline service or a busy hosted service.

The method according to claim 3, wherein the POTS terminal is given a service characteristic that can be applied as follows: The POTS terminal user successfully registers the hotline service or the busy deposit service.

The method according to claim 2, wherein the POTS terminal is given a service that can be used by the POTS terminal to pick up a special tone service or a voice announcement service.

6. The method according to claim 5, wherein the POTS terminal is given a service characteristic that can be applied as follows: the POTS terminal user successfully activates the message light, or the POTS terminal user successfully registers the unconditional call forwarding or Outbound restrictions or DND or absence or phone lockout, or POTS end users entering arrears status, or POTS end users become Centrex users or small pay users.

The method according to claim 3, wherein the PSTN service control unit triggers the applicable service characteristics of the POTS terminal, and includes the following steps:

The PSTN service control unit starts a timer to monitor the POTS terminal user dialing; If the timer expires, the POTS terminal user does not dial, and the service control unit sends a REFER message to the SIP user agent node, instructing the latter to initiate a new hotline number or busy registration number to the hotline or busy registration registration. The SIP initial session request; or the PSTN service control unit sends a REFER message to the hotline number or the busy registration number, instructing the latter to initiate a new SIP initial session request to the POTS end user.

The method according to claim 5, wherein the PSTN service control unit triggers the applicable service characteristics of the POTS terminal, and further includes the following steps:

The new SIP session is successfully established, and the POTS terminal user listens to a special prompt tone or voice prompt.

9. The method according to claim 1, wherein the trigger signal is a flash signal that simulates user signaling.

10. The method of claim 9, wherein the service is a call waiting, or a three-way call, or a conference call, or a fork call transfer, or a malicious call, or a busy callback, or a busy call Registered fork business.

The method according to claim 10, wherein the POTS terminal is given a service characteristic that can be applied as follows: the POTS terminal user successfully activates the service fork service authority or successfully registers the service fork service , or POTS end users online.

12. The method according to claim 1, wherein the trigger signal is an on-hook signal simulating user signaling.

The method according to claim 1, wherein the filtering rule is a subscription, the PSTN service control unit initiates a subscription request for the triggering event to a SIP user agent node, and sends a SIP message, the SIP The message indicates the type of event package of the triggered event that is subscribed through the header field; The SIP user agent node receives a trigger signal corresponding to the trigger event sent by the POTS terminal, and sends a SIP message to the PSTN service control unit according to the subscription instance of the event packet that the POTS terminal has established, and the SIP message passes the header. The domain and the carried event packet indicate that the POTS terminal issues a trigger signal.

14. The method according to claim 13, further comprising the step of canceling the subscription instance by the PSTN service control unit:

The POTS terminal is deprived of the service characteristics that can be applied;

The PST service control unit initiates a corresponding cancel trigger event subscription request to the POTS terminal to be applied, and sends a SIP message to the POTS terminal, indicating the subscribed trigger event in the header field of the SIP message. Event package type and unsubscribe request identifier;

The SIP user agent node receives the SIP message and parses it through the call session control unit, and cancels the created subscription instance for the POTS terminal.

The method according to claim 13, wherein the service control unit periodically or irregularly refreshes the subscribed instance before the subscription instance is cancelled, and re-initiates the corresponding trigger for the applicable service feature of the POTS terminal. Event subscription request.

The method according to claim 13, wherein the PSTN service control unit initiates a subscription request for the trigger event to a SIP user agent node, and the SIP message is a SUBSCRIBE message.

The method according to claim 13, wherein the SIP user agent node receives a trigger signal corresponding to the trigger event sent by the POTS terminal, according to a subscription instance of the event package that has been established by the POTS terminal. In the step of sending a SIP message to the PSTN service control unit, the SIP message is a NOTIFY message.

18. The method of claim 13 wherein the event package can describe one or more trigger signals.