CN101742370B - Method for call processing in communication system, network node and application server - Google Patents

Abstract

The embodiment of the invention provides a method for processing call in a communication system, a network node and an application server. The communication system comprises the network node; and the network node terminates ISDN/PSTN signaling on a user side, and realizes mapping between the ISDN/PSTN signaling and an SIP. The call processing method comprises that: the network node receives call establishing request message, and distributes a B channel resource to an ISDN/PSTN user according to the call establishing request message; and the network node determines a busy/idle state of the ISDN/PSTN according to the locally managed B channel resource, and performs corresponding call processing according to the busy/idle state of the ISDN/PSTN and the condition whether the call number of the ISDN/PSTN user reaches an allowed maximum call number. The call processing method can realize that a network entity under an IMS architecture can realize service call processing according to the occupation condition of the B channel resource.

Description

Method for call processing in communication system, network node and application server

technical field

The invention relates to the technical field of communication, in particular to a method for call processing in a communication system, a network node, an application server and a communication system.

Background technique

With the development of communication technology, Integrated Services Digital Network (ISDN) services have been widely used. In order to realize the separation of data and control flow, ISDN channels are divided into two types, B and D, among which: B channel is a user channel, which is used to transmit user information such as data, voice, image, etc., and the rate is 64kbit/s; D channel It is a control channel, used to transmit public channel signaling and control calls on the B channel of the same interface, and the rate is 64kbit/s or 16kbit/s. Digital Subscriber System No.1 (DSS1) is a protocol on the D channel of the user network interface in the ISDN network, mainly covering the data link layer and the network layer used to control basic calls, corresponding to the ITU In the Q.921 and Q.931 protocols suggested by -T, DSS1 signaling is transmitted through the D channel and complies with the Link Access Procedure on the D Channel (LAPD).

Internet Protocol Multimedia Subsystem (IMS) is a subsystem that provides IP-based multimedia session control in the next generation network, including all core network elements that provide audio, video, text, instant messaging and other multimedia service control. The Session Initiation Protocol (SIP) is used as the IMS control layer protocol to carry call control signaling and provide unified multimedia services and applications.

Traditional telephone switching network (Public Switched Telephone Network, PSTN) / ISDN terminal users will still have a large number of business needs, and it is necessary to provide users of traditional telephone terminals with exactly the same services of the existing PSTN / ISDN network under the IMS architecture. To improve the service experience and improve the quality of service (QoS), the effectiveness of resource management must be enhanced while reducing the complexity of management. However, as shown in Figure 1 is a schematic diagram of the existing typical IMS network architecture, IMS and PSTN/ISDN simulation subsystems are two key subsystems, IMS adopts the core unified with the third generation partnership project (3GPP) control architecture, and the PSTN/ISDN simulation subsystem is used to inherit traditional services, in which, the signaling (dotted line in Figure 1) of the traditional terminal (PSTN/ISDN terminal) and the signaling of the IMS terminal (dashed line in Figure 1) commands are completely independent.

Contents of the invention

Embodiments of the present invention provide a method for call processing in a communication system, a network node, an application server, and a communication system, so as to realize that network entities under the IMS architecture can process service calls according to the resource occupation of the B channel.

An embodiment of the present invention provides a method for call processing in a communication system, the communication system includes a network node, the communication system includes a network node, and the network node terminates ISDN/PSTN signaling on the user side and implements ISDN/PSTN A mapping between signaling and a session initiation protocol SIP, the method comprising:

The network node receives a call establishment request message, and allocates B channel resources for ISDN/PSTN users according to the call establishment request message;

The network node determines the busy/idle status of the ISDN/PSTN user's B channel resource and whether the number of calls of the ISDN/PSTN user reaches the maximum allowed number of calls according to the locally managed B channel resources, and performs corresponding call service processing.

In the above service call processing method, the network node uses the B channel resources managed on it to perceive the occupation of the B channel based on the ISDN/PSTN interface or ISDN/PSTN number, and determines whether to trigger the busy service accordingly, simplifying the process of signaling interaction process.

An embodiment of the present invention provides a method for call processing in a communication system, the communication system includes a network node, the network node terminates ISDN/PSTN signaling on the user side, and implements mapping between ISDN/PSTN signaling and SIP , the method includes:

The network node allocates B channel resources for ISDN/PSTN users during the call connection process for ISDN/SPTN users;

The network node generates a SIP message containing B channel resource occupancy information indicating the B channel resource occupancy status of the ISDN/PSTN user according to locally managed B channel resources;

The network node sends a SIP message indicating the B channel resource occupation information of the ISDN/PSTN user's B channel resource occupation to the application server, so that the application server indicates the ISDN/PSTN user according to the information in the SIP message. Corresponding call service processing is performed based on the B channel resource occupation status information of the B channel resource occupation status.

An embodiment of the present invention provides a network node, and the network node includes:

The message forwarding unit is used to convert the ISDN/PSTN signaling message from the terminal equipment of the ISDN/PSTN user into a session initiation protocol SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message Send to the terminal equipment of ISDN/PSTN users;

The B channel management unit is used to manage B channel resources, and allocates B channel resources for ISDN/PSTN users when the message forwarding unit receives a call establishment request message;

The resource state determination unit is used to determine whether the B channel resource busy status of the ISDN/PSTN user and the number of calls of the ISDN/PSTN user reach the maximum number of calls allowed according to the B channel resources managed by the B channel management unit, and determine the need for Triggered call service;

The call processing unit is configured to perform corresponding call service processing according to the received result determined by the resource state determination unit, and control the message forwarding process of the message forwarding unit.

An embodiment of the present invention provides a network node, and the network node includes:

The message forwarding unit is used to convert the ISDN/PSTN signaling message from the terminal equipment of the ISDN/PSTN user into a session initiation protocol SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message Send to the terminal equipment of ISDN/PSTN users;

The B channel management unit is used to allocate B channel resources for ISDN/PSTN users during the call connection process for ISDN/SPTN users;

The resource occupancy determination unit is used to generate a SIP message containing B channel resource occupancy information indicating the B channel resource occupancy information of the ISDN/PSTN user according to the locally managed B channel resources, and send it to the application server through the message forwarding unit.

An embodiment of the present invention provides an application server, which includes:

The session initialization SIP interface unit is used to communicate with other application servers and/or network nodes through SIP messages;

The B-channel management unit is used to obtain the B-channel resource occupation information carried in the SIP message from the SIP message received by the SIP interface unit, indicating the B-channel resource occupation of ISDN/PSTN users, and store and/or update the local management B channel resources;

A resource status determination unit, configured to determine whether the B channel resource busy status and the ISDN/PSTN user call number reach the maximum number of calls allowed according to the B channel resource managed by the B channel management unit, and determine the call service that needs to be triggered;

The call processing unit is configured to perform corresponding call service processing according to the result output by the resource state determination unit.

The above application server can realize signaling interaction with other application servers or network nodes, better record and/or update the B channel resource occupation information, and can trigger related services according to the above B channel resource occupation information.

An embodiment of the present invention provides a communication system, the communication system includes a network node and an application server, wherein,

The network node is configured to convert the ISDN/PSTN signaling message from the terminal equipment of the ISDN/PSTN user into a SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message. Order the message to be sent to the terminal equipment of the ISDN/PSTN user; in the call connection process for the ISDN/SPTN user, allocate B channel resources for the ISDN/PSTN user; The SIP message of the B channel resource occupation situation information of the B channel resource occupation situation; the SIP message of the B channel resource occupation situation information indicating the B channel resource occupation situation of the ISDN/PSTN user is sent to the application server;

The application server is configured to communicate with the network node through the received SIP message, obtain the B channel resource occupation information carried in the SIP message from the SIP message indicating the B channel resource occupation of ISDN/PSTN users, and store and/or Or update the locally managed B channel resources; perform corresponding call service processing according to the locally managed B channel resources.

The above-mentioned communication system utilizes the network node to terminate the signaling message on the user side, realizes the mapping between the signaling message of the terminal equipment of the ISDN/PSTN user and the SIP message of the server, and generates a message containing the information representing the ISDN/PSTN user The session initialization protocol message of the B channel resource occupation information of the B channel resource occupation is sent to the application server, and the application server performs corresponding call service processing according to the B channel resources when determining to start the corresponding service processing.

Description of drawings

FIG. 1 is a schematic diagram of an existing typical IMS network architecture;

FIG. 2A is a flow chart of Embodiment 1 of service call processing in the present invention;

FIG. 2B is a flow chart of the second embodiment of service call processing in the present invention;

Fig. 3 is a signaling flowchart of an embodiment of service call processing in the present invention;

Fig. 4 is the signaling flow diagram of the application server of the present invention executing the NDUB operation and triggering the embodiment of the call waiting service;

FIG. 5 is a schematic structural diagram of an embodiment of an application server in the present invention;

FIG. 6 is a schematic structural diagram of Embodiment 1 of a network node in the present invention;

FIG. 7 is a schematic structural diagram of Embodiment 2 of a network node in the present invention;

FIG. 8 is a schematic structural diagram of an embodiment of a communication system according to the present invention.

Detailed ways

The technical solutions of the embodiments of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The embodiment of the present invention implements NDUB-related operations in the ISDN service scenario based on the above-mentioned IMS architecture. In the IMS architecture, the MSAN will act as a VGW/Access Gateway (AGW) functional entity, terminate the digital subscriber signaling (DSS1) on the user side, and Realize the mapping between digital user signaling and SIP signaling. In addition, MSAN is responsible for the allocation and management of ISDN/PSTN user channel resources, such as the allocation and management of B channels. The specific allocation management can refer to the definition in TISPAN 183 036. MSAN uses the B channel resources managed on it to perceive the ISDN/PSTN-based Interface or B channel occupancy of ISDN/PSTN number is used as a basis to perform related processing of "whether the resource is full", and can determine whether to trigger the busy service based on this, simplifying the process of signaling interaction. In another embodiment of the present invention, MSAN is responsible for completing the allocation and management of ISDN/PSTN user channel resources, such as the allocation and management of B channels. The specific allocation management can refer to the definition in TISPAN183036, and the channel resources managed by MSAN Send the B channel resource occupation information indicating the B channel resource occupation of ISDN/PSTN users to the application server through a SIP message, and the application server indicates the B channel resource occupation of ISDN/PSTN users according to the information in the SIP message sent by MSAN The B-channel resource occupancy information determines the busy/idle state of the B-channel resource of the ISDN/PSTN user and the maximum number of calls allowed by the ISDN/PSTN user, and can be based on the busy/idle state of the B-channel resource of the ISDN/PSTN user and the allowed /Maximum number of PSTN user calls for corresponding call processing.

In order to simplify the description, ISDN users are used for description in the following, and ISDN users can be extended to PSTN users.

Among them, according to the busy state of the B channel resources of the ISDN/PSTN user and whether the number of calls of the ISDN/PSTN user reaches the maximum number of calls allowed, corresponding call service processing is performed, including but not limited to one or more of the following combinations Condition:

1. If channel B resources are busy, and the number of calls to the ISDN number/ISDN interface has reached the maximum value, the call establishment request is rejected and a 486 response can be returned.

2. If the B channel resources are idle, and the number of calls of the ISDN number/ISDN interface has reached the maximum value, the call establishment request is rejected and a 486 response can be returned.

3. If the B channel resource is idle, and the number of calls of the ISDN number/ISDN interface has not reached the maximum value, the call establishment request is allowed, but the call waiting service will not be triggered, and the connection process will be performed as a normal call.

4. If channel B resources are busy, and the number of calls of the ISDN number/ISDN interface does not reach the maximum value, the call waiting service will be triggered.

The above ISDN number/ISDN interface is used to identify ISDN users.

As shown in Figure 2A, it is a flow chart of the first embodiment of service call processing in the present invention, and Figure 2A shows that the network node realizes the B channel resource busy/idle detection of ISDN/PSTN users according to the B channel resources managed on it, and according to the busy/idle The detection result triggers the corresponding call processing.

Step 101, the network node receives the call setup request message, and distributes the B channel resources for ISDN/PSTN users according to the above call setup request message;

For the calling ISDN/PSTN user, the call establishment request is carried on the control channel from the calling ISDN/PSTN user, such as the call establishment request message of the D channel, which is used to establish a call with the calling ISDN/PSTN user; Call ISDN/PSTN user, this call establishment request message is the SIP call establishment request message from application server, is used for setting up the call with called ISDN/PSTN user;

Step 102, determine whether the ISDN/PSTN user who needs to set up a call has ordered a busy service, if so, perform step 103, otherwise perform step 104;

In addition, allocate B channel resources for ISDN/PSTN users who need to establish calls according to the received call establishment request message;

Step 103, according to the B channel resources of ISDN/PSTN users of local management, determine whether the B channel resources of ISDN/PSTN users are busy or idle and whether the number of calls of this ISDN/PSTN user reaches the maximum number of calls allowed, and accordingly carry out corresponding Call business processing;

For specific call processing, refer to the above description, and details will not be repeated here. Among them, according to the ISDN/PSTN user's B channel resource busy state, the number of calls of the ISDN/PSTN user, these two parameters are matched with the locally stored ISDN/PSTN user service processing decision condition, see above.

Step 104: Determine the busy/idle state of the ISDN/PSTN user's B channel resource according to the locally managed ISDN/PSTN user's B channel resource, and reject the call establishment request if busy.

In the above service call processing method, the MSAN uses the B channel resources managed on it to sense the occupation of the B channel based on the ISDN/PSTN interface or ISDN/PSTN number, and determines whether to trigger the busy service accordingly, simplifying the signaling interaction process .

As shown in Figure 2B, it is a flow chart of the second embodiment of service call processing in the present invention, and Figure 2B shows that the network node will represent the B channel resources of the B channel resources occupied by ISDN/PSTN users according to the B channel resources locally managed The occupancy information is sent to the application server through the SIP message, so that the application server can judge the busy/idle state of the channel resource of the ISDN/PSTN user according to the B channel resource occupancy information in the SIP message and realize the busy/idle detection on the call, and trigger according to the busy/idle detection result Corresponding call service processing, such as performing call waiting service or busy call completion service, etc.

Step 201, the network node receives the call setup request message, and allocates B channel resources for ISDN/PSTN users according to the call setup request message;

For the calling ISDN/PSTN user, the call establishment request is carried on the control channel from the calling ISDN/PSTN user, such as the call establishment request message of the D channel, which is used to establish a call with the calling ISDN/PSTN user;

For the called ISDN/PSTN user, the call setup request message is a SIP call setup request message from the application server, which is used to set up a call with the called ISDN/PSTN user;

The network node can query the locally managed B channel resources according to the call establishment request message, and allocate B channel resources for ISDN/PSTN users;

Step 202, the network node sends a SIP message containing B channel resource occupation information indicating the B channel resource occupation status of the ISDN/PSTN user to the AS according to the locally managed B channel resources;

Wherein, in the process of establishing a call for the calling ISDN/PSTN user and/or the called ISDN/PSTN user, the network node can obtain the capability information indicating that the AS supports channel resource negotiation from the SIP message sent by the AS, and start the procedure accordingly 202 operation;

In particular, when the network node establishes a call for the called ISDN/PSTN user, the capability information indicating that the AS supports channel resource negotiation can be carried in the SIP call establishment request message sent by the AS to the network node to save procedures and reduce message interaction;

Step 203, the AS stores and/or updates the locally managed B channel resources according to the B channel resource occupancy information in the SIP message sent by the network node, and determines the ISDN/PSTN user's busy/idle status according to the B channel resources locally managed by the AS Check whether the number of calls with the ISDN/PSTN user reaches the maximum number of calls allowed, and perform corresponding call processing accordingly.

For example, perform call waiting service or busy call completion service, etc.

In the process of the above method, it can be judged on the AS whether the ISDN/PSTN user has registered a predetermined busy service, and according to the judgment result, it is determined whether to send capability information indicating that the AS supports channel resource negotiation to the network node, so as to notify the network node to feed back the ISDN service to the AS. /PSTN user's B channel resource occupancy information.

In the embodiment of the above service call processing method, the network node sends the B channel resource occupation information indicating the B channel resource occupation of ISDN/PSTN users to the application server through a SIP message according to the channel resources managed on it, and the application server according to the above In the SIP message, the B channel resource occupation information indicating the B channel resource occupation of ISDN/PSTN users determines the busy status of the B channel resources of the ISDN/PSTN users and the maximum number of calls allowed by the ISDN/PSTN users, and can be based on The B channel resource busy/idle state of the ISDN/PSTN user and the maximum number of calls allowed by the ISDN/PSTN user are correspondingly processed.

As shown in FIG. 3 , it is a signaling flow chart of the service call processing embodiment of the present invention. The call processing takes the application server AS to implement corresponding call processing according to the B channel resource occupation and the number of calls of ISDN users as an example. The signaling flow chart of service call processing as shown in Figure 3, can clearly see that calling party ISDN user (caller), calling party MSAN (O-MSAN), calling party AS from this signaling flowchart (O-AS), called party AS (T-AS), called party MSAN (T-MSAN) and called party ISDN user (callee), the process of starting a new call in Figure 3 Call setup messages include: DSS1 reminder message (DSS1 ALERTING message), DSS1 connection message (DSS1 CONNECT message), DSS1 connection confirmation message (DSS1 CONNECT ACK), DSS1 progress message (DSS1 PROGRESS message), DSS1 setup message (DSS1SETUP message), DSS1 setup message Confirmation message (DSS1 SETUP ACK message); the message to end a call includes: DSS1 release message (DSS1 RELEASE message), DSS1 release completion message (DSS1 REL COM message). The call flow includes:

The calling party ISDN user sends a call setup request message (DSS1 SETUP message) to the calling party MSAN through the D channel;

In steps 301-302, the calling party MSAN receives the call setup request message carried on the D channel, and the calling party MSAN sends a SIP request message to the called party AS through the calling party AS. This process can use the INVITE message defined by the SIP standard ,No longer;

Step 303, in the call connection process, if the called party AS judges that the called party ISDN user has registered the CW service, and the parameter is set to "AS executes NDUB", then in the SIP request (SIP INVITE) sent to the called party MSAN ) message needs to carry the information Supported: ChanStatus indicating that the AS supports channel resource negotiation, so as to notify the called party MSAN to report channel resource occupancy. An example of a SIP INVITE message that meets the above requirements is as follows:

INVITE sip:+8675511111huawei.com; user＝phone SIP/2.0

Call-ID: c006b979a8938e0683bcc9096ba308bc

From:<sip:+8675512345huawei.com; user＝phone>; tag＝7f1f90f1

To:<sip:+8675511111huawei.com; user＝phone>

Supported:ChanStatus //Indicates that the AS supports channel resource negotiation

Content-Length:...

Content-Type: application/sdp

Steps 304 to 306, the called party MSAN sends a SIP response message to the calling party MSAN through the called party AS and the calling party AS in turn. This process can use the 183 message defined by the SIP standard, and will not be described again;

In addition, MSAN also sends DSS1 reminder messages to ISDN users;

Step 307, during the call connection process, the called party MSAN determines that the AS supports channel resource negotiation according to the information Supported:ChanStatus indicating that the AS supports channel resource negotiation in the SIP INVITE message, and then generates B channel resource occupation according to the locally managed B channel resources The SIP message of the situation information, and return the generated SIP message containing the B channel resource occupation information to the called party AS, so that the called party AS can record and/or refresh the B channel resource of the ISDN interface or ISDN number accordingly occupancy. Among them, the SIP message containing the resource occupancy information of the B channel is a SIP200 response message, and the resource occupancy information of the B channel is represented by an extended xml code. An example of a SIP200 response message that meets the above requirements is as follows:

SIP/2.0200OK

Call-ID: c006b979a8938e0683bcc9096ba308bc

From:<sip:+86755612345huawei.com; user＝phone>; tag＝7f1f90f1

To:<sip:+8675511111huawei.com; user=phone>; tag=314159

Content-Length:...

Content-Type: multipart/mixed; boundary＝Boundary42

--Boundary42

Content-Length:...

Content-Type: application/ChannelStatus+xml//Indicates the resource occupation of channel B

<?xml version="1.0" encoding="UTF-8"?>

<ChannelStatus state="ChannelFullBusy">

<uri>sip:+8675511111huawei.com</uri>

</Channel Status>

--Boundary42

Content-Length:...

Content-Type: application/sdp

Step 308, the called party AS sends a SIP response message to the calling party AS, which may adopt the SIP200 message defined by the SIP standard;

Step 309, during the call connection process, if the calling party AS judges that the calling party ISDN user has registered the CW service, one embodiment of the present invention is that the calling party AS executes NDUB, then the SIP200 message sent to the calling MSAN The information Supported:ChanStatus indicating that the AS supports channel resource negotiation needs to be carried in the message, so that the calling MSAN can determine that the AS supports channel resource negotiation based on the information Supported:ChanStatus in the SIP200 message indicating that the AS supports channel resource negotiation. An example of a SIP200 message that meets the above requirements is as follows :

SIP/2.0200OK

Call-ID:d432fa84b4c76e66710

From:<sip:+86755612345huawei.com; user＝phone>; tag＝43524545

To:<sip:+8675511111huawei.com; user=phone>; tag=a3343df32

Supported:ChanStatus //Indicates that the AS supports channel resource negotiation

Content-Length:...

Content-Type: application/sdp

Steps 310-312, the calling party MSAN sends a SIP ACK message to MSAN through the calling party AS and the called party AS in turn; here, steps 310-312 are optional;

Step 313, during the call connection process, if the calling party MSAN judges that the received SIP200 message contains the ability information Supported:ChanStatus indicating that the AS supports channel resource negotiation, then after the SIP dialogue is established, send a SIP Update message, and in The SIP Update message carries B channel resource occupancy information indicating the B channel resource occupancy, where the B channel resource occupancy information is expressed in xml code, so that the calling party AS can record and/or refresh the ISDN interface or ISDN number accordingly The calling party AS can determine whether to trigger a busy service, such as a call waiting service or a busy call completion service, according to the B channel resource occupancy status managed on it; the example of a SIP Update message that meets the above requirements is as follows:

UPDATE sip:+8675511111huawei.com; user＝phone SIP/2.0

Call-ID:d432fa84b4c76e66710

From:<sip:+8675512345@huawei.com; user＝phone>; tag＝43524545

To:<sip:+8675511111huawei.com; user=phone>; tag=a3343df32

Content-Length:...

Content-Type: application/ChannelStatus+xml//Indicates the resource occupancy of channel B

<?xml version="1.0" encoding="UTF-8"?>

<Channel Status state="ChannelFullBusy">

<uri>sip:+8675512345huawei.com</uri>

</ChannelStatus>

Step 314, the calling party AS sends a SIP200 message to the calling party MSAN;

Step 315, in the call release process, the release party MSAN, that is, the calling party MSAN, carries the B channel resource occupancy situation of the extended xml code representation in the SIP release request (SIP BYE) message, and the calling party AS records and/or Or refresh the B channel resource occupancy of the ISDN interface or ISDN number. An example of a SIP BYE message that meets the above requirements is as follows:

BYE sip:+8675511111huawei.com; user＝phone SIP/2.0

Call-ID:d432fa84b4c76e66710

From:<sip:+8675512345huawei.com; user＝phone>; tag＝43524545

To:<sip:+8675511111huawei.com; user=phone>; tag=a3343df32

Content-Length:...

Content-Type: application/ChannelStatus+xml//Indicates the resource occupancy of channel B

<?xml version="1.0" encoding="UTF-8"?>

<ChannelStatus state="ChannelFullBusy">

<uri>sip:+8675512345huawei.com</uri>

</ChannelStatus>

Steps 316～317, the calling party AS sends a SIP release (SIP BYE) message to the called party MSAN through the called party AS, the existing standard practice can be adopted in the SIP release message, and the resource occupation of the B channel is not included;

Step 318, during the call release process, the MSAN at the released side, that is, the MSAN of the called party, carries in the SIP200 message the B-channel resource occupancy of the extended xml code representation, and the called party AS records and/or refreshes the ISDN interface accordingly Or the resource occupation of the B channel of the ISDN number. An example of a SIP200 message that meets the above requirements is as follows:

SIP/2.0 200 OK

Call-ID:d432fa84b4c76e66710

From:<sip:+86755612345huawei.com; user＝phone>; tag＝43524545

To:<sip:+8675511111huawei.com; user=phone>; tag=a3343df32

Content-Length:...

Content-Type: application/Channel Status+xml//Indicates the resource occupancy of channel B

<?xml version="1.0" encoding="UTF-8"?>

<ChannelStatus state="ChannelFullBusy">

<uri>sip:+8675511111huawei.com</uri>

</ChannelStatus>

Steps 319-320, standard practice, no special requirements.

In addition, the above-mentioned steps 315-320 are the processing flow executed when the calling party sends the release request message. Similarly, if the callee sends the release request message, the subsequent operation flow is completely equivalent to the steps 315-320 , which will not be described here.

Through the signaling interaction processing between the above service control entities, the AS can learn the required resource status information, and determine whether the call waiting service can be triggered accordingly; as shown in Figure 4, the application server of the present invention performs the NDUB operation And trigger the signaling flowchart of the call waiting service embodiment, according to the definition of NDUB judging conditions in ITU-T Q.953.1, the execution result of NDUB includes the following several situations: 1, B channel resources are busy, and the ISDN number/ If the number of calls on the ISDN interface has reached the maximum value, the call establishment request is rejected and a 486 response is returned. 2. If the B channel resources are idle, and the number of calls based on the ISDN number/ISDN interface has reached the maximum value, the call establishment request is rejected and a 486 response is returned. 3. If the B channel resource is idle, and the number of calls of the ISDN number/ISDN interface has not reached the maximum value, the call establishment request is allowed, but the call waiting service will not be triggered, and the connection process will be performed as a normal call. 4. If channel B resources are busy, and the number of calls of the ISDN number/ISDN interface does not reach the maximum value, the call waiting service will be triggered. The signaling interaction process in this case includes:

Step 401, AS receives SIP call setup request (SIP INVITE) message;

Step 402, AS executes NDUB-related processing and judgment, that is, judges whether the busy state of the B channel resource of the ISDN/PSTN user and the number of calls of the ISDN/PSTN user reach the maximum number of calls allowed, if the judgment result of NDUB is to trigger call waiting service, then the SIP INVITE message sent to MSAN needs to carry the service indication P-Service-Indication, the service identification can use the extended enhanced Backus-Naur Form (ABNF) format, described as follows:

P-Service-Indication="P-Service-Indication"

                               

Indication = "CW"

Step 403, MSAN receives the SIP call setup request (SIP INVITE) message from AS, and judges whether the indication "cw" representing the call waiting service is carried in the service indication P-Service-Indication;

Step 404, if the indication "cw" representing the call waiting service is carried in the service indication P-Service-Indication, then the Info in the channel identification (Channel identification) IE in the DSS1 call setup request (DSS1SETUP) message sent to the user side The .Chan sel field needs to be set to 00 (No channel), and the channel is indicated as "00", which means that there is no channel, that is, call waiting is required, so that the terminal equipment of the ISDN/PSTN user detects the channel identifier in the DSS1SETUP message and performs call waiting.

Through the signaling interaction processing between the service control entities shown in Figure 3, the application server can learn the B channel resource occupancy information required to execute the NDUB judgment process, and see whether the call waiting service is triggered based on this information in Figure 4 processing flow.

As shown in Figure 5, it is a schematic structural diagram of an embodiment of the application server of the present invention, and the application server includes:

The SIP interface unit 21 is used to communicate with other application servers and/or network nodes (such as MSAN) through SIP messages; other application servers can be the calling application server of the network to which the calling ISDN/PSTN user belongs, and the network node can be the It is called MSAN; other application servers can also be called application servers of the network to which the called ISDN/PSTN user belongs, and the network node can be called MSAN.

The B-channel management unit 22 is configured to obtain, from the SIP message received by the SIP interface unit 21, the B-channel resource occupancy information carried in the SIP message to represent the B-channel resource occupancy of ISDN/PSTN users, and store and/or update Locally managed B-channel resources;

The resource state determination unit 23 is used to perform the NDUB operation of the ISDN/PSTN user according to the B channel resource managed by the B channel management unit 22, that is, to determine the busy state of the B channel resource of the ISDN/PSTN user and the number of calls of the ISDN/PSTN user Whether to reach the maximum number of calls allowed, when the business type that needs to be triggered is determined, the call processing unit 24 is notified to carry out corresponding call processing; the resource status determination unit 23 can monitor the SIP message received by the SIP interface unit 21, trigger the operation of NDUB to Determine whether to start the corresponding business processing.

The call processing unit 24 is used to perform corresponding call services according to the result output by the resource status determination unit 23, namely the busy/idle status of the B channel resource of the ISDN/PSTN user, and whether the number of calls of the ISDN/PSTN user reaches the maximum number of calls allowed Processing, call completion service or call waiting service if busy.

The above-mentioned application server may also include a B channel resource negotiation unit 25, configured to notify the SIP interface unit to send a SIP message indicating the capability information of the AS supporting channel resource negotiation to the MSAN.

The above application server can realize signaling interaction with other application servers or network nodes, better record and/or update the B channel resource occupation information, and can trigger related services according to the above B channel resource occupation information.

As shown in FIG. 6, it is a schematic structural diagram of Embodiment 1 of a network node of the present invention, and the network node includes:

The message forwarding unit 30 is used to convert the ISDN/PSTN signaling message from the terminal equipment of the ISDN/PSTN user into a SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message and send it to the Terminal equipment for ISDN/PSTN users;

The B channel management unit 34 is used to manage the B channel resources. When the message forwarding unit 30 receives the call setup request message, it distributes the B channel resources for ISDN/PSTN users, wherein, if the call setup request is from the calling ISDN/PSTN user ISDN/PSTN signaling call setup request message, then B channel management unit 34 allocates B channel resources for the calling ISDN/PSTN user; if the call setup request is a SIP call setup request message from the application server, then B channel management unit 34 is The called ISDN/PSTN user allocates B channel resources.

Resource state determination unit 35, is used for determining whether the B channel resource busy state of ISDN/PSTN user and the call number of this ISDN/PSTN user reach the maximum call number allowed according to the B channel resource managed by B channel management unit 34, and according to This determination requires the call service to be triggered. Refer to the above description for the judgment process.

The call processing unit 36 is configured to perform corresponding call service processing according to the received result determined by the resource status determining unit 35 , and control the message forwarding process of the message forwarding unit 30 .

The message forwarding unit 30 specifically includes an ISDN/PSTN interface unit 31 , a mapping unit 32 and a SIP interface unit 33 . The ISDN/PSTN interface unit 31 is configured to provide a communication interface with ISDN/PSTN user terminal equipment, and receive signaling messages from or to ISDN/PSTN. The SIP interface unit 33 is configured to provide a SIP interface with the application server, and receive SIP messages from or to the application server. Wherein, the ISDN/PSTN interface unit 31 sends the mapping unit 32 from the ISDN/PSTN signaling message, and the mapping unit 32 converts the ISDN/PSTN signaling message into a SIP message, and sends the SIP message to the SIP interface unit 33; The unit 33 sends the SIP message from the application server to the mapping unit 32 , and the mapping unit 32 converts the SIP message into an ISDN/PSTN signaling message and sends it to the ISDN/PSTN interface unit 31 .

The network node above also includes: a configuration management unit 37 configured to configure parameters of the message forwarding unit 30 , such as message conversion and mapping parameters of the mapping unit 32 .

The above-mentioned ISDN/PSTN signaling message may be a DSS1-based signaling message. The above-mentioned network node can allocate B-channel resources for the calling party ISDN/PSTN user and/or the called party ISDN/PSTN user, and according to the B-channel resources managed on the calling party ISDN/PSTN user and/or the called party ISDN/PSTN user The PSTN user provides corresponding call service processing, and the call service processing refers to the above description, and will not be repeated here.

The above-mentioned network nodes do not need to exchange information with the application server, but make decisions based on locally managed B-channel resources to determine whether to trigger the busy service. Since the network nodes are directly connected to ISDN/PSTN users, they can respond to user requests more quickly. If necessary, the load on the application server can be reduced when there is no need to charge for busy services; if charging for busy services is required, the network node can record the records of busy services locally, and record the busy services periodically Or send based on the request of the application server (or billing server) for billing.

As shown in FIG. 7, it is a schematic structural diagram of Embodiment 2 of the network node of the present invention, and the network node includes:

The message forwarding unit 30 is used to convert the ISDN/PSTN signaling message into a SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message and send it to the terminal equipment of the ISDN/PSTN user;

The B channel management unit 34 is used for distributing B channel resources for ISDN/PSTN users during the call connection process for ISDN/SPTN users;

The resource occupancy determination unit 38 is used to generate a SIP message containing the B channel resource occupancy information indicating the B channel resource occupancy of the ISDN/PSTN user according to the locally managed B channel resources, and send it to the application through the message forwarding unit 30 server.

The message forwarding unit 30 specifically includes an ISDN/PSTN interface unit 31 , a mapping unit 32 and a SIP interface unit 33 . The ISDN/PSTN interface unit 31 is configured to provide a communication interface with ISDN/PSTN user terminal equipment, and receive signaling messages from or to ISDN/PSTN. The SIP interface unit 33 is configured to provide a SIP interface with the application server, and receive SIP messages from or to the application server. Wherein, the ISDN/PSTN interface unit 31 sends the mapping unit 32 from the ISDN/PSTN signaling message, and the mapping unit 32 converts the ISDN/PSTN signaling message into a SIP message, and sends the SIP message to the SIP interface unit 33; The unit 33 sends the SIP message from the application server to the mapping unit 32 , and the mapping unit 32 converts the SIP message into an ISDN/PSTN signaling message and sends it to the ISDN/PSTN interface unit 31 .

The network node above also includes: a configuration management unit 37 configured to configure parameters of the message forwarding unit 30 , such as message conversion and mapping parameters of the mapping unit 32 .

The above-mentioned network node can send the B-channel resource occupancy information indicating the B-channel resource occupancy of the ISDN/PSTN user to the application server through the SIP message according to the channel resources managed on it, and the application server can send the information according to the SIP message sent by the MSAN. B channel resource occupancy information of ISDN/PSTN user's B channel resource occupancy information determines the B channel resource busy status of the ISDN/PSTN user and whether the number of calls of the ISDN/PSTN user reaches the maximum number of calls allowed, and can be used according to Then, the corresponding call service processing is performed, and the call service processing refers to the above description, and will not be repeated here. In addition, the above-mentioned network node may be MSAN or the like.

The above-mentioned network node can send the B-channel resource occupancy situation information indicating the B-channel resource occupancy situation of the ISDN/PSTN user to the application server through a SIP message according to the channel resources managed thereon, and the application server can represent ISDN/PSTN according to the above-mentioned SIP message. The B channel resource occupation status information of PSTN user's B channel resource occupation status determines whether the B channel resource busy state of the ISDN/PSTN user and the number of calls of the ISDN/PSTN user have reached the maximum number of calls allowed, and can be determined according to the determined As a result, corresponding call service processing is performed.

As shown in FIG. 8 , it is a schematic structural diagram of an embodiment of a communication system of the present invention. The system includes a network node 1 and an application server 2, wherein the above-mentioned network node 1 is used to transmit ISDN/PSTN information from terminal equipment of ISDN/PSTN users The signaling message is converted into a SIP message and sent to the above-mentioned application server 2, and the SIP message from the above-mentioned application server 2 is converted into an ISDN/PSTN signaling message and sent to the terminal equipment of the ISDN/PSTN user; making a call for the ISDN/SPTN user During the connection process, allocate B channel resources for ISDN/PSTN users; generate a SIP message containing B channel resource occupancy information indicating the B channel resource occupancy information of the above ISDN/PSTN users according to the locally managed B channel resources; will indicate the above ISDN The SIP message of the B channel resource occupation information of the /PSTN user's B channel resource occupation situation is sent to the application server 2; the application server 2 is used to communicate with the network node 1 through the received SIP message, and obtain the SIP from the SIP message The B channel resource occupation information carried in the message indicates the B channel resource occupation of ISDN/PSTN users, and store and/or update the locally managed B channel resources; perform corresponding call service processing according to the locally managed B channel resources.

The above-mentioned communication system utilizes the network node to terminate the signaling message on the user side, realizes the mapping between the signaling message of the terminal equipment of the ISDN/PSTN user and the SIP message of the server, and generates the B containing the above-mentioned ISDN/PSTN user. The session initialization protocol message of channel resource occupancy information of B channel resource occupancy information is sent to the application server, and the application server performs corresponding call service processing according to the above-mentioned B channel resources when determining to start corresponding call service processing.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (7)

1. A method for call processing in a communication system, characterized in that the communication system includes a network node, and the network node terminates the ISDN/PSTN signaling of the user side, and realizes the ISDN/PSTN For mapping between signaling and SIP, the method includes: The network node allocates B channel resources for ISDN/PSTN users during the call connection process for ISDN/PSTN users; The network node generates a SIP message containing B channel resource occupancy information indicating the B channel resource occupancy status of the ISDN/PSTN user according to locally managed B channel resources; The network node sends a SIP message indicating the B channel resource occupation information of the ISDN/PSTN user's B channel resource occupation to the application server, so that the application server indicates the ISDN/PSTN user according to the information in the SIP message. Corresponding call service processing is performed based on the B channel resource occupation status information of the B channel resource occupation status. 2. the method for call processing in the communication system according to claim 1, is characterized in that, described network node generates the B channel that comprises the B channel resource occupancy situation that represents described ISDN/PSTN user according to the B channel resource of local management Before the SIP message of resource occupation situation information, the method also includes: The network node receives a SIP message from the application server including capability information indicating that the application server supports B-channel resource negotiation. 3. A network node, characterized in that, comprising: The message forwarding unit is used to convert the ISDN/PSTN signaling message from the terminal equipment of the ISDN/PSTN user into a session initiation protocol SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message Send to the terminal equipment of ISDN/PSTN users; The B channel management unit is used to allocate B channel resources for ISDN/PSTN users during the call connection process for ISDN/PSTN users; The resource occupancy determination unit is used to generate a SIP message containing the B channel resource occupancy information representing the B channel resource occupancy information of the ISDN/PSTN user according to the locally managed B channel resource, and send it to the application server through the message forwarding unit. 4. The network node according to claim 3, wherein the message forwarding unit comprises: The ISDN/PSTN interface unit is used to provide a communication interface with the terminal equipment of the ISDN/PSTN user, and receive ISDN/PSTN signaling messages from or to the terminal equipment of the ISDN/PSTN user; The SIP interface unit is used to provide a SIP interface with the application server, and receive SIP messages from or to the application server; The mapping unit is used to convert ISDN/PSTN signaling messages into SIP messages, send the SIP messages to the SIP interface unit and convert the SIP messages into ISDN/PSTN signaling messages, and send them to the ISDN/PSTN interface unit. 5. An application server, characterized in that, comprising: The session initialization SIP interface unit is used to communicate with other application servers and/or network nodes through SIP messages; The B-channel management unit is used to obtain the B-channel resource occupation information carried in the SIP message from the SIP message received by the SIP interface unit, indicating the B-channel resource occupation of ISDN/PSTN users, and store and/or update the local management B channel resources; A resource status determination unit, configured to determine whether the B channel resource busy status and the ISDN/PSTN user call number reach the maximum number of calls allowed according to the B channel resource managed by the B channel management unit, and determine the call service that needs to be triggered; The call processing unit is configured to perform corresponding call service processing according to the result output by the resource status determining unit. 6. The application server according to claim 5, further comprising: The channel resource negotiation unit is configured to notify the SIP interface unit to send a SIP message indicating the capability information of the application server where it is located supports channel resource negotiation to the network node. 7. A communication system, comprising a network node and an application server, characterized in that: The network node is configured to convert the ISDN/PSTN signaling message from the terminal equipment of the ISDN/PSTN user into a SIP message and send it to the application server, and convert the SIP message from the application server into an ISDN/PSTN signaling message. The message is sent to the terminal equipment of the ISDN/PSTN user; during the call connection process for the ISDN/PSTN user, the B channel resource is allocated for the ISDN/PSTN user; according to the local management of the B channel resource generation, it contains the information indicating the ISDN/PSTN user The SIP message of the B channel resource occupation situation information of the B channel resource occupation situation; the SIP message of the B channel resource occupation situation information indicating the B channel resource occupation situation of the ISDN/PSTN user is sent to the application server; The application server is configured to communicate with the network node through the received SIP message, obtain the B channel resource occupation information carried in the SIP message from the SIP message indicating the B channel resource occupation of ISDN/PSTN users, and store and/or Or update the locally managed B channel resources; perform corresponding call services according to the locally managed B channel resources. the

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