CN101127697A - Flow control method and system under the framework of separation of media control and processing - Google Patents

Abstract

The invention relates to the field of communication, and discloses a flow control method and system under the framework of separation of media control and processing, so that the service will not be interrupted when the quality of the CS network is poor. In the present invention, if the highest rate required by the CS side is lower than the lowest rate of the current codec of the media stream, the codec of the media stream is updated according to the requirement of the CS side. In the H.245 message packet, the event descriptor and the observation event descriptor for selecting the codec value are added. The media processing device or the media control device may select a codec for the media stream, and notify related devices to modify the codec for the media stream. It is also possible to bidirectionally close the original logical channel between the media control device and the CS side, and then open a new logical channel for the media stream, triggering related devices to renegotiate a new codec for the media stream.

Description

Flow control method and system under the framework of separation of media control and processing

technical field

The invention relates to the communication field, in particular to the flow control technology under the framework of separation of media control and processing.

Background technique

The traditional network is based on Time Division Multiplexing (Time Division Multiplexing, referred to as "TDM") public switched telephone network (Public Switched Telephone Network, referred to as "PSTN") voice network, with circuit switching (Circuits Switch, referred to as "CS") Mainly, it was originally designed and constructed for transmitting voice, ensuring voice quality, and undertaking voice services, and its services and controls are completed by switches.

With the continuous development of communication technology, various services of the Internet, mobile communication network, and fixed-line communication network continue to infiltrate and merge. Application Protocol, referred to as "WAP") and video conferencing and other emerging business types.

In order to increase the network transmission rate and enrich the types of network services, the new-generation network architecture separates the media control device from the media processing device, as shown in Figure 1. The media control device completes call control and instructs the media processing device to operate media resources. The media processing device provides media resources and operates the media resources according to the instructions of the media control device. The media control device and the media processing device interact through a media control protocol, such as the H.248 protocol. Media control devices include but are not limited to Media Gateway Controller (Media Gateway Controller, "MGC"), Mobile Services Switching Center (Mobile services Switching Center, "MSC") server, and Multimedia Resource Function Controller (Multimedia Resource Function Controller) , referred to as "MRFC"), etc. Media processing equipment includes but is not limited to Media Gateway (Media GateWay, referred to as "MGW") and Multimedia Resource Function Processor (Multimedia Resource Function Processor, referred to as "MRFP").

The media control protocol adopted between the media control device and the media processing device, the H.248 protocol, and the multimedia communication control protocol H.245 protocol adopted by the CS network are introduced below.

The H.248 protocol is defined by the International Telecommunication Union Telecommunication Standardization Sector ("ITU-T" for short) SG 16 standard organization, and is a protocol specially used for media resource control.

The basic principle of the H.248 protocol is to abstract various resources on the media processing device into a network, which is further divided into a physical network and a temporary network. The physical network represents some semi-permanent physical entities, such as TDM time slots; the temporary network represents the public resources released after temporary application and use, such as RealTime Transfer Protocol (RealTime Transfer Protocol, referred to as "RTP") flow. The combination of networks is abstracted as context, and topology is used to describe the relationship between networks. Based on these abstractions, call connection is actually an operation on the network and context, and is completed through command requests and responses between the media control device and the media processing device. Commands include addition, modification, deletion, notification, etc.; command parameters are called descriptions Symbols, including properties (Property), signals (Signal), events (Event), statistics (Statistic), parameters with business relevance are logically aggregated into a package (Package). A packet is a method provided by the H.248 protocol to extend protocol functions. The H.248 protocol expands the functions of the protocol through the package, and adds new functions to the protocol. Generally, it is not necessary to modify the protocol body, but only need to define a new package (Package). A package can be regarded as an encapsulation of an independent feature. When a media processing device claims to support this package, it means that it supports this feature. The media control device can use the properties, events, signals, and statistics defined in the package to operate the media. Process the media resources on the device and implement the corresponding business logic.

The H.245 protocol is a control protocol for multimedia communication formulated by ITU-T.

The H.245 protocol defines a series of procedures used for in-band negotiation at the beginning of the communication or during the communication process. These procedures are used to realize: exchanging voice, video and data capabilities; requesting the transmission of special voice, video or data modes; management Logical channels used to transmit voice, video, and data information; perform master-slave determination; transmit various control and indication signals; control the bit rate of a single logical channel or the entire multiplex; and calculate the loopback delay.

The H.245 protocol also defines the syntax and semantics of network messages. These messages cover receiving and sending capabilities, mode priority at the receiving end, logical channel signaling, control and indication, etc. Response signaling process is adopted to ensure reliable audio, video and data communication.

The H.245 protocol includes Command messages, which are used to request the peer end to perform certain operations according to the commands of the local end after the call is established. Command class messages include "flow control command" messages. It is used to notify the peer end when the network quality of the local end changes after the call is established, and requires the peer end to control the bit rate of a certain media stream or the entire multiplexed stream sent to the local end.

In order to enable the existing CS service to continue in the future IP network, the 3rd Generation Partnership Project (3rd Generation Partnership Project, referred to as "3GPP") proposed an IP-based multimedia subsystem (IP based Multimedia Subsystem, referred to as "IMS"), IMS is a system specially designed for the next-generation all-IP multimedia mobile network, focusing on using IP networks to carry mobile multimedia services. The 3GPP specification introduces the concept of IMS, mainly hoping to Provide traditional CS services (such as voice services) in the form of IMS, and hope to realize all multimedia services provided to users through this IMS system. IMS uses the IP packet domain as the bearer channel for its control signaling and media transmission, and uses the Session Initiation Protocol (SIP) as the call control signaling to establish, maintain and terminate voice and multimedia processes, realizing business Management, session control, and bearer access are separated.

When establishing a multimedia session between the IMS and the CS network, signaling intercommunication and user data intercommunication between the IMS network and the CS network need to be completed through a media control device and a media processing device. Generally, the IMS network uses the SIP protocol as the control signaling, and the CS network uses the H.245 protocol as the multimedia communication control protocol. Wherein, the SIP control signaling of the IMS network is terminated at the media control device, and the H.245 media control signaling of the CS network can be terminated at the media control device or at the media processing device.

Generally, the establishment of a multimedia session between the IMS and the CS network requires the following procedures:

1) Establish communication between the IMS and the media control device through a control protocol, such as the SIP protocol;

2), the media control device requires the media processing device to reserve media resources for the IMS endpoint through a media control protocol, such as the H.248 protocol;

3), the media control device requires the media processing device to reserve media resources for the CS endpoint through a media control protocol, such as the H.248 protocol;

4), when the media processing device terminates the H.245 message, the media processing device opens the one-way logical channel from the media processing device to the CS, and the CS opens the one-way logical channel from the CS to the media processing device; the media control device terminates the H.245 When receiving a message, the media control device opens a one-way logical channel from the media control device to the CS, and the CS opens a one-way logical channel from the CS to the media control device.

In the multimedia session between IMS and CS, when the quality of the CS network decreases, in order to ensure the transmission quality, the CS side will perform flow control on the received media stream, and the "flow control command" flow control message of the H. The sending rate of the media stream.

According to the different conditions of the termination of the H.245 message in the media processing device and the media control device, there are two different processes for flow control of the media stream.

When the "flow control command" message of the H.245 protocol is terminated in the media processing device:

After the multimedia session is established, when the quality of the CS network decreases, the CS side sends the H.245 "flow control command" message to the media processing device to limit the upper limit of the bit rate of a single logical channel or the entire multiplexed logical channel at the remote end. The media processing device reports the message to the media control device through a media control protocol, such as H.248.12. After receiving the "flowcontrol command" message sent by the CS side, the media control device requires the media processing device to modify the media stream at the CS multiplexing endpoint and IMS endpoint according to the upper limit of the bit rate of the media stream in the logical channel contained in the "flow control command" message. bitrate cap. The media processing device performs flow control on the media stream according to the instructions of the media control device, and subsequent services are not affected. When the highest bit rate defined by the CS side for the media stream is lower than the lowest bit rate for the media processing device to send the media stream to the CS side, the media processing device stops transmitting the media stream.

When the "flow control command" message of the H.245 protocol is terminated in the media control device:

After the multimedia session is established, when the quality of the CS network deteriorates, the CS side sends a "flow control command" message of the H.245 protocol to the media control device to limit the upper limit of the bit rate of a single logical channel or the entire multiplexed logical channel at the remote end. After the media control device receives the "flowcontrol command" message sent by the CS side, according to the upper limit of the media stream bit rate in the logical channel contained in the "flow control command" message, the media processing device is required to modify the CS multiplexing endpoint and the IMS endpoint media stream. bitrate cap. The media processing device performs flow control on the media stream according to the instructions of the media control device, and subsequent services are not affected. When the highest bit rate defined by the CS side for the media stream is lower than the lowest bit rate for the media processing device to send the media stream to the CS side, the media control device requires the media processing device to stop transmitting the media stream.

In practical application, there is the following problem: when the quality of the CS network is poor, the service may be interrupted.

The main reason for this situation is that when the network quality of the CS network is poor, the transmission bit rate of a single logical channel or the entire multiplexed logical channel at the remote end is limited, and the maximum bit rate limited for media streams on the CS side is lower than When the media processing device sends the media stream to the lowest bit rate on the CS side, the media processing device will stop the transmission of the media stream, resulting in interruption of its services.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a flow control method and system under the framework of separation of media control and processing, so that services will not be interrupted when the quality of the CS network is poor.

In order to achieve the above object, the present invention provides a flow control method under the framework of separation of media control and processing, comprising the following steps:

If the highest rate required by flow control on the CS side of circuit switching is lower than the lowest rate of the current codec of the media stream, update the codec of the media stream from the media processing device to the IP multimedia subsystem IMS, and from the media processing device to the CS side to comply with The codec required by the flow control on the CS side.

Wherein, the step of updating codec includes the following sub-steps:

The media processing device respectively selects a first codec and a second codec that meet the flow control requirements of the CS side for the media streams from the local end to the CS side and from the IMS to the local end;

The media processing device notifies the IMS through the media control device to modify the codec of the media stream to a second codec;

The media processing device closes the logical channel originally opened for the media stream, and then opens a new logical channel for the media stream, and uses the first codec on the new logical channel.

In addition, in the method, the media control device instructs the media processing device to detect that the highest rate required by the CS side flow control is lower than the lowest rate of the current codec of the media stream by selecting the codec value event, and When the media processing device can respectively select the first codec and the second codec that meet the flow control requirements of the CS side for the media stream from the local end to the CS side and the IMS to the local end, report the corresponding observation event and carry the selected codec .

In addition, in the method, the step of updating the codec includes the following sub-steps:

The media processing device respectively selects a first codec and a second codec candidate set that meet the flow control requirements of the CS side for media streams from the local end to the CS side and from the IMS to the local end;

The media processing device notifies the IMS of the candidate set of the second codec through the media control device, and the IMS selects one of the candidate sets from the candidate set as the second codec, and modifies the codec of the media stream to the second codec at the local end. Codec, and notify the media processing device to modify the codec of the media stream in the IMS endpoint to a second codec through the media control device;

The media processing device closes the logical channel originally opened for the media stream, and then opens a new logical channel for the media stream, and uses the first codec on the new logical channel.

In addition, in the method, the step of updating the codec includes the following sub-steps:

The media control device respectively selects a first codec and a second codec that meet the flow control requirements of the CS side for the media streams from the media processing device to the CS side and from the IMS to the media processing device;

The media control device notifies the media processing device to modify the codec of the media stream in the CS multiplexing endpoint and the IMS endpoint to the first codec and the second codec respectively;

The media control device closes the logical channel originally opened for the media stream, and then opens a new logical channel for the media stream, and uses the first codec on the new logical channel;

The media control device notifies the IMS to modify the codec of the media stream to the second codec.

In addition, in the method, the step of updating the codec includes the following sub-steps:

The media control device respectively selects a first codec and a second codec candidate set that meet the flow control requirements of the CS side for media streams from the media processing device to the CS side and from the IMS to the media processing device;

The media control device notifies the IMS of the candidate set of the second codec, and the IMS selects one of the candidate sets as the second codec, modifies the codec of the media stream to the second codec at the local end, and notifies all The second codec selected by the media control device;

The media control device notifies the media processing device to modify the codec of the media stream in the CS multiplexing endpoint and the IMS endpoint to the first codec and the second codec respectively;

The media control device closes the logical channel originally opened for the media stream, and then opens a new logical channel for the media stream, and uses the first codec on the new logical channel.

In addition, in the method, the CS side and the media processing device interact to close the logical channel originally opened for the media stream between the CS side and the media processing device in both directions, and then for the media stream The media stream opens a new logical channel, triggering the media processing device to renegotiate a new codec.

In addition, in the method, the CS side and the media control device interact to close the logical channel originally opened for the media stream between the CS side and the media processing device in both directions, and then for the media stream The media stream opens a new logical channel, triggering the media control device to renegotiate a new codec.

In addition, in the method, the media control device notifies the IMS through a SIP message to modify the codec of the media stream to the second codec.

Furthermore, in the method, the logical channels are opened and closed by H.245 commands.

In addition, in the method, the media processing device or media control device judges whether the highest rate required by the CS side for flow control is lower than the lowest rate of the current codec of the media stream according to the flow control command from the CS side.

The present invention also provides a flow control system under the framework of separation of media control and processing, including:

A device for detecting whether the maximum rate required by the flow control on the CS side is lower than the minimum rate of the current codec of the media stream;

It is used to update the codec of the media stream from the media processing device to the IMS and from the media processing device to the CS side to comply with the CS side when the highest rate required by the flow control on the CS side is lower than the minimum rate of the current codec of the media stream Codec device required by flow control.

Through comparison, it can be found that the main difference between the technical solution of the present invention and the prior art is that if the highest rate required by the CS side is lower than the minimum rate of the current codec of the media stream, the codec of the media stream is updated according to the CS side requirement. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

By adding the event descriptor for codec value selection and the observation event descriptor in the H.245 message packet, the media processing device can make the maximum rate required by the flow control on the CS side lower than the minimum rate of the current codec of the media stream, and this When the terminal has the ability to select a codec that meets the flow control requirements of the CS side, it reports to the media control device the new codec selected for the media stream from the local end to the CS side and from the IMS to the local end.

The media processing device or the media control device may select a codec for the media stream, and notify related devices to modify the codec for the media stream. Compared with the prior art, this solution only involves the modification of the media processing device and the media control device, and can be better compatible with the existing CS side device and IMS device.

The media processing device or the media control device may select a codec candidate set for the IMS, and the IMS selects the most suitable codec from the candidate set. This solution substantially increases the negotiation process on the new codec between the media processing device or media control device and the IMS, so that the best codec can be comprehensively determined according to the actual conditions of the media processing device or media control device and the IMS.

It is also possible for the CS side to close the original logical channel between the CS side and the media processing device in both directions by interacting with the media processing device or the media control device, and then open a new logical channel for the media stream to trigger the media stream Renegotiate the new codec. This solution requires less changes to the media processing device and the media control device.

Description of drawings

FIG. 1 is a schematic diagram of separation of a media control device and a media processing device in the prior art;

FIG. 2 is a flowchart of a flow control method under the framework of separation of media control and processing according to the first embodiment of the present invention;

3 is a schematic diagram of interaction between a media control device and a media processing device in a stream control method under a media control and processing separation framework according to a first embodiment of the present invention;

FIG. 4 is a flowchart of a flow control method under the framework of separation of media control and processing according to the third embodiment of the present invention;

FIG. 5 is a flowchart of a flow control method under the framework of separation of media control and processing according to the fifth embodiment of the present invention;

Fig. 6 is a flowchart of a flow control method under the framework of separation of media control and processing according to the seventh embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

The core of the present invention is that when the highest rate required by the CS side is lower than the lowest rate of the current codec of the media stream, the codec of the media stream from the media processing device to the IMS and from the media processing device to the CS side is updated according to the CS side requirements. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

The flow control method under the framework of separation of media control and processing in the first embodiment of the present invention will be described below according to the principle of the invention. In this embodiment, the H.245 message is terminated at the media processing device.

As shown in FIG. 2, in step 201, the media control device instructs the media processing device to detect that the highest rate required by the CS side flow control is lower than the lowest rate of the current codec of the media stream by selecting the codec value event, and The media processing device can respectively select the first codec and the second codec that meet the flow control requirements of the CS side for the media streams from the local end to the CS side and from the IMS to the local end, and report corresponding observation events with the selected codecs.

Among them, the selected codec value event is a newly defined event for the situation that the media processing device detects that the maximum rate required by the CS side flow control is lower than the minimum rate of the current codec of the media stream. The specific definition is as follows:

Event Name (event name) : ChoiceCodecValue (choice codec value)

EventID (event ID) : ccv(0x0001)

Description (descriptor) : Indicates that the media processing device detects that the maximum rate required by the flow control on the circuit switching CS side is lower than the minimum rate of the current codec of the media stream, and the media processing device can respectively connect from the local end to the CS side and from the IMS to the IMS side. When the media stream at the local end selects the first codec and the second codec that meet the flow control requirements of the CS side, report the corresponding observation event and carry the selected codec.

According to the newly defined selected codec value event, for the case where the H.245 message is terminated in the media processing device, an event descriptor is added to the H.245 message packet in the existing H.248.12 protocol, and the media control device passes The descriptor of the selected codec value event notifies the media processing device to compare the rate and select the codec. The specific definition of the event descriptor is as follows:

Events Descriptor (event descriptor)

Parameter Name (parameter name): ChoiceCodecValue (choose codec value)

ParameterID (parameter identification) : ccv(0x0001)

Description (descriptor) : Instructs the media processing device to detect whether the maximum rate required by the circuit switching CS side flow control is lower than the minimum rate of the current codec of the media stream, and when it is lower than the minimum rate of the current codec of the media stream, it is the local end respectively Select the first codec and the second codec that meet the flow control requirements of the CS side for the media stream to the CS side and the IMS to the local end, and report the corresponding observation event, carrying the selected codec.

Type (type) : enumeration

Optional (whether optional) : yes

Possible values (possible values): a codec that meets the requirements

Default (default value): None

In addition to adding an event descriptor in the H.245 message packet, an observation event descriptor needs to be added. The media processing device reports the codec it chooses by including the parameter value "ChoiceCodecValue" in the observation event descriptor. The specific definition of the observation event descriptor is as follows:

Observed Events Descriptor (observation event descriptor)

Parameter Name (parameter name): ChoiceCodecValue (choose codec value)

Parameter ID (parameter identification): ccv(0x0001)

Description (descriptor) : The media processing device detects that the maximum rate required by the flow control on the circuit switching CS side is lower than the minimum rate of the current codec of the media stream, and the media processing device can respectively connect the local end to the CS side and the IMS to the local end. When the media stream at the end selects the first codec and the second codec that meet the flow control requirements of the CS side, report the corresponding observation event and carry the selected codec.

Type (type) : enumeration

Optional (whether optional) : yes

Possible values (possible values): a codec that meets the requirements

Default (default value): None

By adding the event descriptor for codec value selection and the observation event descriptor in the H.245 message packet, the media processing device can make the maximum rate required by the flow control on the CS side lower than the minimum rate of the current codec of the media stream, and this When the terminal has the ability to select a codec that meets the flow control requirements of the CS side, it reports to the media control device the new codec selected for the media stream from the local end to the CS side and from the IMS to the local end.

Then enter step 202, the media processing device monitors according to the instructions of the media control device, and when receiving the "flow control command" message of the H.245 protocol sent by the CS side, the media processing device reports the "flow control command" to the media control device "information.

Then enter step 203, the media processing device judges whether the maximum rate limited by the CS side to the media stream indicated in the "flow control command" message is lower than the minimum rate of the current encoding and decoding of the media stream, and if so, respectively from the local end to the CS side Select the first codec and the second codec that meet the flow control requirements of the CS side for the media stream from the IMS to the local end. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

Then enter step 204, the media processing device sends an H.245CLC close logical channel message to the CS side, closing the logical channel originally opened for the media stream.

Then enter step 205, the media processing device reports the selected codec value event to the media control device, and includes the selected first codec and the second codec in the ChoiceCodecValue (selected codec value) parameter of the reported selected codec value event .

Then enter step 206, after the media control device updates the codec corresponding to the media stream in the Session Description Protocol (Session Description Protocol, referred to as "SDP") according to the second codec reported by the media processing device, it sends a SIP message to the IMS to notify The IMS modifies the codec of the media stream to the second codec.

Then enter step 207, after receiving the message from the media control device, the IMS updates the codec corresponding to the media stream in the local SDP to the second codec, and returns a SIP message to the media control device.

Then enter step 208, after receiving the SIP message, the media control device notifies the media processing device to modify the codec of the media stream in the CS multiplexing endpoint and the IMS endpoint to the first codec and the second codec respectively. Since the codec is selected for the media stream through the media processing device, and the relevant device is notified to modify the codec for the media stream, compared with the prior art, only the modification of the media processing device is involved, and it can be better compatible with the existing CS side device and IMS device compatible.

Then enter step 209, the media processing device sends an H.245OLC open logical channel message to the CS side, opens a new logical channel for the media stream, and uses the first codec on the new logical channel.

The above is the process flow of the flow control method under the framework of the separation of media control and processing in this embodiment. According to the process, the interaction between the media processing device and the media control device will be described as an example when the H.245 message is terminated by the media processing device. .

The interaction is shown in Figure 3, where the media control device is the MGCF, and the media processing device is the IM-MGW. First, in step 301, the MGCF uses the H.248 modification/event descriptor to instruct the IM-MGW to detect that the maximum rate required by the CS side flow control is lower than the minimum rate of the current codec of the media stream, and the IM-MGW When the first codec and the second codec that meet the flow control requirements of the CS side can be selected for the media stream from the local end to the CS side and from the IMS to the local end, report the corresponding observation event and carry the selected codec. After receiving the modification/event descriptor, the IM-MGW returns a corresponding response.

Then in step 302, the IM-MGW monitors according to the instructions of the MGCF, and when receiving the "flow control command" message of the H.345 protocol sent by the CS side, the IM-MGW sends an H.248 notification event/flow control to the MGCF Command, report the "flow control command" message. The MGCF returns a corresponding response.

Then in step 303, the IM-MGW judges whether the maximum rate limited by the CS side to the media stream indicated in the "flow control command" message is lower than the minimum rate of the current codec of the media stream, and if so, the rate from the local end to the CS The media stream from the side and the IMS to the local end selects the first codec and the second codec that meet the flow control requirements of the CS side, and reports the first codec and the second codec to the MGCF through the H.248 notification event/coding. The MGCF returns a corresponding response.

Then in step 304, the MGCF notifies the IM-MGW through the H.248 modification/remote descriptor to modify the codec of the media stream in the CS multiplexing endpoint and the IMS endpoint to the first codec and the second codec respectively. The IM-MGW returns a corresponding response after receiving it. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

The flow control method under the separation framework of media control and processing in the second embodiment of the present invention is roughly the same as that in the first embodiment, the only difference is that in the first embodiment, the maximum rate required for flow control on the CS side is lower than that of the media flow When the current codec is at the lowest rate, the media processing device selects the first codec and the second codec that meet the flow control requirements of the CS side for the media streams from the local end to the CS side and from the IMS to the local end; and in this embodiment, When the highest rate required by the flow control on the CS side is lower than the lowest rate of the current codec of the media stream, the media processing device selects the first codec that meets the flow control requirements on the CS side for the media stream from the local end to the CS side and from the IMS to the local end. , and the second codec candidate set, the media processing device notifies the IMS of the second codec candidate set through the media control device, and the IMS selects one from the candidate set as the second codec, and the codec of the media stream at the local end The decoding is modified to the second codec, and the media processing device is notified by the media control device to modify the codec of the media stream in the IMS endpoint to the second codec. This solution substantially increases the negotiation process on the new codec between the media processing device or the media control device and the IMS, so that the best codec can be comprehensively determined according to the actual conditions of the media processing device or the media control device and the IMS.

The flow control method under the framework of separation of media control and processing according to the third embodiment of the present invention will be described below. In this embodiment, the H.245 message is terminated at the media control device.

As shown in Figure 4, in step 401, when the media control device receives the "flow control command" message of the H.245 protocol sent by the CS side, it determines whether the maximum rate limited by the CS side to the media stream indicated in the message is low Based on the lowest rate of the current codec of the media stream, if it is, select the first codec and the second codec that meet the flow control requirements of the CS side for the media streams from the media processing device to the CS side and from the IMS to the media processing device. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

Then enter step 402, where the media control device sends an H.245CLC close logical channel message to the CS side to close the logical channel originally opened for the media stream.

Then enter step 403, after the media control device updates the codec corresponding to the media stream in the SDP to the second codec, it sends a SIP message to the IMS to notify the IMS to modify the codec of the media stream to the second codec.

Then enter step 404, after receiving the message from the media control device, the IMS updates the codec corresponding to the media stream in the local SDP to the second codec, and sends a SIP message to the media control device.

Then enter step 405, after receiving the SIP message, the media control device notifies the media processing device to modify the codec of the media stream in the CS multiplexing endpoint and the IMS endpoint to the first codec and the second codec respectively. Since the media control device only selects the codec for the media stream and notifies the relevant devices to modify the codec for the media stream, compared with the prior art, only the modification of the media control device is involved, and it can be compared with the existing CS side equipment and IMS equipment. Very compatible.

Then enter step 406, the media control device sends an H.245OLC open logical channel message to the CS side, opens a new logical channel for the media stream, and uses the first codec on the new logical channel.

The flow control method under the framework of separation of media control and processing in the fourth embodiment of the present invention is roughly the same as that in the third embodiment, the only difference is that in the third embodiment, the maximum rate required for flow control on the CS side is lower than that of the media stream When the current codec is at the lowest rate, the media control device selects the first codec and the second codec that meet the flow control requirements of the CS side for the media streams from the media processing device to the CS side and from the IMS to the media processing device; and in this implementation In this mode, when the highest rate required by the flow control on the CS side is lower than the minimum rate of the current encoding and decoding of the media stream, the media processing device selects the media streams that comply with the CS side flow control for the media streams from the media processing device to the CS side and from the IMS to the media processing device. The required first codec and the candidate set of the second codec, the media control device notifies the IMS of the candidate set of the second codec, and the IMS selects one from the candidate set as the second codec, and sends the media stream at the local end The codec of the codec is changed to the second codec, and the selected second codec is notified to the media control device. The media control device notifies the media processing device to modify the codec of the media stream in the CS multiplexing endpoint and the IMS endpoint respectively to the first codec and the selected second codec. This solution substantially increases the negotiation process on the new codec between the media processing device or the media control device and the IMS, so that the best codec can be comprehensively determined according to the actual conditions of the media processing device or the media control device and the IMS.

The flow control method under the framework of separation of media control and processing according to the fifth embodiment of the present invention will be described below. In this embodiment, the CS side mainly closes the original logical channel between the CS side and the media processing device in both directions through the interaction with the media processing device or the media control device, and then opens a new logical channel for the media stream to trigger Renegotiate a new codec for this media stream. This solution requires less changes to the media processing device and the media control device. In this embodiment, the H.245 message is terminated at the media processing device.

As shown in Figure 5, in step 501, the media control device instructs the media processing device to detect that the highest rate required by the flow control on the CS side of the circuit switching is lower than the lowest rate of the current codec of the media stream by selecting the codec value event, and The media processing device can respectively select the first codec and the second codec that meet the flow control requirements of the CS side for the media streams from the local end to the CS side and from the IMS to the local end, and report corresponding observation events with the selected codecs.

In step 502, when the network quality degrades, the CS side sends a "flow control command" message of the H.245 protocol to the media processing device to limit the maximum rate required by the CS side flow control.

Then enter step 503, the media processing device reports the event to the media control device through the existing technology, and at the same time the media processing device stops sending the media stream.

Then enter step 504, the media processing device judges whether the maximum rate limited to the media stream by the CS side indicated in the "flow control command" message is lower than the minimum rate of the current codec of the media stream, and if so, sends "flow control command" to the CS side indication" message, indicating that the rate at this time is 0.

Then enter step 505, after receiving the "flow control indication" message from the media processing device, the CS side sends a "request mode" message to the media processing device to close the logic opened for the media flow between the local end and the media processing device aisle.

Then enter step 506, the CS side sends a CLC close logical channel message to the media processing device, and selects a new codec. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

Then enter step 507, the CS side sends an OLC open logical channel message to the media processing device, and opens a new logical channel between the local end and the media processing device for the media stream.

Then enter step 508, the media processing device reports the "request mode" message sent by the CS side, the CLC close logical channel message, and the OLC open logical channel message.

Then enter step 509, where the media processing device sends a CLC close logical channel message to close the logical channel opened for the media stream from the local end to the CS side.

Then enter step 510, the media processing device reports the selected codec value event to the media control device, and the ChoiceCodecValue (selected codec value) parameter of the selected codec value event of the report includes the local terminal to which the media processing device selects for the media stream. The first codec on the CS side and the second codec on the IMS side to the local end. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

Then enter step 511, the media control device updates the codec corresponding to the media stream in the SDP according to the second codec reported by the media processing device, and then sends a SIP message to the IMS to notify the IMS to modify the codec of the media stream to the second codec. Codec.

Then enter step 512, after receiving the message from the media control device, the IMS updates the codec corresponding to the media stream in the local SDP to the second codec, and returns a SIP message to the media control device.

Then enter step 513. After the media control device receives the SIP message, it notifies the media processing device to revise the SDP corresponding to the media stream of the CS multiplexing endpoint and the IMS endpoint, and the coded code adopted by the media stream of the CS multiplexing endpoint and the IMS endpoint. The decoding is modified to the first codec and the second codec respectively.

Then enter step 514, the media processing device sends an OLC open logical channel message to the CS side, and opens a one-way logical channel from the local end to the CS side.

The flow control method under the framework of separation of media control and processing in the sixth embodiment of the present invention is roughly the same as that in the fifth embodiment, the only difference is that in the fifth embodiment, the maximum rate required for flow control on the CS side is lower than that of the media stream When the current codec is at the lowest rate, the media processing device selects the first codec and the second codec that meet the flow control requirements of the CS side for the media streams from the local end to the CS side and from the IMS to the local end; and in this embodiment, When the highest rate required by the flow control on the CS side is lower than the lowest rate of the current codec of the media stream, the media processing device selects the first codec that meets the flow control requirements on the CS side for the media stream from the local end to the CS side and from the IMS to the local end. , and the second codec candidate set, the media processing device notifies the IMS of the second codec candidate set through the media control device, and the IMS selects one from the candidate set as the second codec, and the codec of the media stream at the local end The decoding is modified to the second codec, and the media processing device is notified by the media control device to modify the codec of the media stream in the IMS endpoint to the second codec. This solution substantially increases the negotiation process on the new codec between the media processing device or the media control device and the IMS, so that the best codec can be comprehensively determined according to the actual conditions of the media processing device or the media control device and the IMS.

The flow control method under the framework of separation of media control and processing according to the seventh embodiment of the present invention will be described below. In this embodiment, the CS side mainly closes the original logical channel between the CS side and the media processing device in both directions through the interaction with the media processing device or the media control device, and then opens a new logical channel for the media stream to trigger Renegotiate a new codec for this media stream. This solution requires less changes to the media processing device and the media control device. In this embodiment, the H.245 message is terminated at the media control device.

As shown in FIG. 6, in step 601, when the network quality is degraded, the CS side sends a "flow control command" message of the H.245 protocol to the media control device to limit the maximum rate required by the CS side flow control.

Then enter step 602, the media control device judges whether the maximum rate limited to the media stream by the CS side indicated in the "flow control command" message is lower than the minimum rate of the current codec of the media stream, and if so, instructs the media processing device to stop sending the media stream media stream.

Then enter step 603, the media control device sends a "flow control indication" message to the CS side, indicating that the rate at this time is 0.

Then enter step 604, after receiving the "flow control indication" message from the media control device, the CS side sends a "request mode" message to the media control device to close the logic opened for the media flow between the local end and the media control device aisle.

Then enter step 605, the CS side sends a CLC close logical channel message to the media control device, and selects a new codec. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

Then enter step 606, the CS side sends an OLC open logical channel message to the media control device to open a new logical channel between the local end and the media control device for the media stream.

Then enter step 607, the media control device sends a CLC close logical channel message to close the logical channel opened for the media stream from the local end to the CS side.

Then enter step 608, the media control device selects an updated second codec for the media stream between the media processing device and the IMS, and sends the selected second codec to the IMS through a SIP message.

Then enter step 609, after receiving the message from the media control device, the IMS updates the codec corresponding to the media stream at the local end to the second codec, and returns a SIP message to the media control device.

Then enter step 610, after the media control device receives the SIP message, it notifies the media processing device to revise the SDP corresponding to the media stream of the CS multiplexing endpoint and the IMS endpoint, and the coded code adopted by the media stream of the CS multiplexing endpoint and the IMS endpoint The decoding is modified to the first codec and the second codec respectively.

Then enter step 611, the media control device sends an OLC open logical channel message to the CS side, and opens a one-way logical channel from the local end to the CS side.

The flow control method under the media control and processing separation framework of the eighth embodiment of the present invention is roughly the same as the seventh embodiment, the only difference is that in the seventh embodiment, the media control device is the media processing device and the IMS The media stream selects a second codec that meets the requirements of the CS, and sends the selected second codec to the IMS through a SIP message; and in this embodiment, the media control device selects a second codec for the media stream between the media processing device and the IMS. The second codec candidate set that meets the CS requirements, and sends the selected second codec candidate set to the IMS through a SIP message, and the IMS selects one from the candidate set as the second codec, and sends the media stream at the local end The codec of the codec is changed to the second codec, and the selected second codec is notified to the media control device. This solution substantially increases the negotiation process on the new codec between the media processing device or the media control device and the IMS, so that the best codec can be comprehensively determined according to the actual conditions of the media processing device or the media control device and the IMS.

In the ninth embodiment of the present invention, the flow control system under the framework of separation of media control and processing includes a device for detecting whether the highest rate required by the flow control on the CS side is lower than the lowest rate of the current codec of the media stream; When the maximum rate required by the side flow control is lower than the minimum rate of the current codec of the media stream, update the codec of the media stream from the media processing device to the IMS and from the media processing device to the CS side to the codec that meets the flow control requirements of the CS side device of. By updating the codec, the media stream can meet the flow control requirements at a rate greater than 0, thereby maintaining service continuity.

The media processing device and media control device referred to in the present invention may also have other names in different application environments, but their functions are the same. For example, a media processing device is often called a media gateway, and a media control device is often called a media gateway controller, a soft switch, and the like.

Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the present invention. The spirit and scope of the invention.

Claims (12)

1. medium control separates the flow control method under the framework with processing, it is characterized in that, comprises following steps:

The flank speed that the control of ifs circuit exchange CS effluent requires is lower than the minimum speed limit of the current encoding and decoding of Media Stream, then the encoding and decoding of medium processing device to IP Multimedia System IMS, medium processing device to the Media Stream of CS side is updated to respectively to meet the encoding and decoding that the control of described CS effluent requires.

2. medium control according to claim 1 separates the flow control method under the framework with processing, it is characterized in that the step of described renewal encoding and decoding comprises following substep:

Described medium processing device is respectively local terminal and selects to meet first encoding and decoding and second encoding and decoding that the control of described CS effluent requires to CS side and IMS to the Media Stream of local terminal;

Described medium processing device notifies IMS that the encoding and decoding of described Media Stream are revised as second encoding and decoding by described medium control device;

Described medium processing device is closed original logical channel for described Media Stream unlatching, opens new logical channel for this Media Stream again, uses first encoding and decoding in this new logical channel.

3. medium control according to claim 2 separates the flow control method under the framework with processing, it is characterized in that, described medium control device is by selecting encoding and decoding value incident, indicate described medium processing device to be lower than the minimum speed limit of the current encoding and decoding of Media Stream in the flank speed that detects circuit switching (CS) effluent control requirement, and this medium processing device can be respectively the Media Stream of local terminal to CS side and IMS to local terminal when selecting to meet first encoding and decoding that the control of described CS effluent requires and second encoding and decoding, reports corresponding observed events and carries the encoding and decoding of selection.

4. medium control according to claim 1 separates the flow control method under the framework with processing, it is characterized in that the step of described renewal encoding and decoding comprises following substep:

Described medium processing device is respectively the Media Stream of local terminal to CS side and IMS to local terminal and selects to meet first encoding and decoding that the control of described CS effluent requires and the Candidate Set of second encoding and decoding;

Described medium processing device is by the Candidate Set of described medium control device notice IMS second encoding and decoding, IMS selects a kind of as second encoding and decoding from this Candidate Set, at local terminal the encoding and decoding of described Media Stream are revised as second encoding and decoding, and notify described medium processing device that the encoding and decoding of Media Stream described in the IMS end points are revised as second encoding and decoding by described medium control device;

Described medium processing device is closed original logical channel for described Media Stream unlatching, opens new logical channel for this Media Stream again, uses first encoding and decoding in this new logical channel.

5. medium control according to claim 1 separates the flow control method under the framework with processing, it is characterized in that the step of described renewal encoding and decoding comprises following substep:

Described medium control device is respectively medium processing device and selects to meet first encoding and decoding and second encoding and decoding that the control of described CS effluent requires to CS side and IMS to the Media Stream of medium processing device;

Described medium control device notifies described medium processing device that the encoding and decoding of Media Stream described in multiplexing end points of CS and the IMS end points are revised as first encoding and decoding and second encoding and decoding respectively;

Described medium control device is closed original logical channel for described Media Stream unlatching, opens new logical channel for this Media Stream again, uses first encoding and decoding in this new logical channel;

Described medium control device notice IMS is revised as second encoding and decoding with the encoding and decoding of described Media Stream.

6. medium control according to claim 1 separates the flow control method under the framework with processing, it is characterized in that the step of described renewal encoding and decoding comprises following substep:

Described medium control device is respectively the Media Stream of medium processing device to CS side and IMS to medium processing device and selects to meet first encoding and decoding that the control of described CS effluent requires and the Candidate Set of second encoding and decoding;

The Candidate Set of described medium control device notice IMS second encoding and decoding, IMS selects a kind of as second encoding and decoding from this Candidate Set, at local terminal the encoding and decoding of described Media Stream are revised as second encoding and decoding, and notify described medium control device selected second encoding and decoding;

Described medium control device notifies described medium processing device that the encoding and decoding of Media Stream described in multiplexing end points of CS and the IMS end points are revised as first encoding and decoding and second encoding and decoding respectively;

Described medium control device is closed original logical channel for described Media Stream unlatching, opens new logical channel for this Media Stream again, uses first encoding and decoding in this new logical channel.

7. medium control according to claim 1 separates the flow control method under the framework with processing, it is characterized in that, described CS side and described medium processing device are by mutual, in the two-way logical channel of originally opening between described CS side and the described medium processing device of all closing for described Media Stream, open new logical channel for this Media Stream again, trigger described medium processing device and consult new encoding and decoding again.

8. medium control according to claim 1 separates the flow control method under the framework with processing, it is characterized in that, described CS side and described medium control device are by mutual, in the two-way logical channel of originally opening between described CS side and the described medium processing device of all closing for described Media Stream, open new logical channel for this Media Stream again, trigger described medium control device and consult new encoding and decoding again.

9. separate flow control method framework under with processing according to each described medium control in the claim 2 to 5, it is characterized in that described medium control device notifies IMS that the encoding and decoding of described Media Stream are revised as second encoding and decoding by sip message.

10. separate flow control method under the framework with processing according to each described medium control in the claim 2 to 8, it is characterized in that, by H.245 ordering the described logical channel of opening and closing.

11. separate flow control method under the framework with processing according to each described medium control in the claim 2 to 8, it is characterized in that, described medium processing device or medium control device, according to flow-control command, judge whether the flank speed of CS effluent control requirement is lower than the minimum speed limit of the current encoding and decoding of Media Stream from described CS side.

12. medium control separates the flow control system under the framework with processing, it is characterized in that, comprises:

Whether the flank speed that is used to detect CS effluent control requirement is lower than the equipment of the minimum speed limit of the current encoding and decoding of Media Stream;

Be used for when the flank speed of CS effluent control requirement is lower than the minimum speed limit of the current encoding and decoding of Media Stream, the encoding and decoding of medium processing device to IMS and medium processing device to the Media Stream of CS side be updated to the equipment that meets the encoding and decoding that the control of described CS effluent requires respectively.

Images