CN100452895C - Method and device of implementing media resource control in soft switch call server - Google Patents

Abstract

The present invention relates to a method and apparatus of implementing media resource control in softswitch call server. Said call server controls media resource on media gateway through gateway control protocol. Said method includes the steps of: using Leg model to define incoming media resource and corresponding outgoing media resource respectively for each media stream between said call server and said media gateway, wherein using calling LegID to identify said incoming media resource and called LegID to identify said outgoing media recourse; a call service function module in said call server identifying and managing said calling LegID and called LegID; setting a media gateway controller(MGC) module in said call server which further processes the media stream identified by said calling LegID and called LegID. The present invention is employed to implement complete separation of control and bear, and simplify the complexity of media control flow in call control layer.

Description

In the call server of soft switch, realize the method and apparatus of media resource control

Technical field

The present invention relates to communication technical field, relate to the method and apparatus of in the call server of soft switch, realizing media resource control especially.

Background technology

In the traditional exchange network, all directly relevant with switch to function or business that user terminal provides, control signaling and voice/data carrying concentrate in the conventional switch.Conventional switch has constituted the exchcange core of traditional exchange network.For each user terminal, traditional " calling out and control " function and business combine, the CCF difference of different business demands, and conventional switch can not realize controlling and separating that voice/data carries thus.

Along with the evolution of network technology, in the future communications network design that mobile network and fixed network merge gradually, particularly the notion of next generation network (NGN) has appearred in IP technology and be the development of the broadband network of representative with the IP network.NGN is a kind of comprehensive, open network architecture, and multiple business such as voice, data and multimedia can be provided.NGN can be on unified packet network business such as converged communication, information, ecommerce and transaction, satisfy diversified, personalized business demand, on the basis of inheriting, realize and the miscellaneous service network, the for example intercommunication between public switch telephone network (PSTN)/Integrated Service Digital Network, public land mobile radio communication (PLMN), Intelligent Network, the Internet provides fused business such as new voice, data, video traffic fast in the whole network.

NGN adopts Softswitch technology, the principle that followed that carrying and control are separated, control and user plane is separated.The basic conception of soft switch is that CCF is separated from transport layer (media gateway).By server, for instance, the software on the call server in NGN (Call Sever) is realized the basic call controlled function, as calling out route, management control (set up session, remove session), signalling interworking.NGN mainly is with in the conventional switch aspect the network architecture, and the signaling control section separates with the voice/data bearing part, and H.248/Megaco the MGCP of middle use standard for example carries out mutual.That is to say, in the soft-exchange construction of NGN, by call server by MGCP such as MGCP, H.248 wait the media resource of controlling on the media gateway.

In 3GPP R4 protocol infrastructure, the circuit domain of core network has realized separating of carrying and control, and MSC (mobile switching centre) is broken down into Mobile Switching Center Server (MSCServer) and media gateway (MGW).The function of MSC Server is a business function, simultaneously by the controlled function of Mc interface enforcement to media gateway., soft exchanging system is being introduced in the mobile core network, the Call server of MSC can be MSC Server herein; The Call server of GMSC (GMSC (gateway mobile switching center)) can be GMSC Server; The MGW of MSC can be MSC MGW; The MGW of GMSC can be GMSC MGW or be called for short GMGW.

In the framework of soft switch, media resource comprises as multiple carryings such as IP, ATM, E1.Calling out the control of control and medium and adopt what kind of implementation method, is that call server is realized the key of the multiple media resource of control flexibly.

The several different methods that can adopt call server realizes the control to media resource.In the agreement 3GPP of current proposition TS 23.205 about " Bearer Independent CS CoreNetwork " part a kind of method that is realized media resource control by call server is disclosed, control media resource simultaneously by call control layer, the media resource data are kept at call control layer.Call control layer carries out media resource control when finishing call proceeding.

Referring to accompanying drawing 1, accompanying drawing 1 has exemplarily been described the method for the calling medium control that realization is general on call server.Usually, the main two class functions that realize on call server, a class is medium control and management function, another kind of is other controlled function.First kind function mainly is to be used for controlling media gateway, for miscellaneous service is set up bearer channel on media gateway, and release of bearer channel, modification, reconstruction or the like, the function of this class is called bearer control signalling (Bear Control Signalling).Another kind of function on the call server then is called call control signalling (Call Control Signalling).In the prior art, shown in accompanying drawing 1, the call server model is unified in bearer control signalling and these two kinds of signaling process functions of call control signalling in the same functional entity, just in call service function CSF (CallService Function) entity.CSF is directly by call bearer control CBC (CallBearer Control) interface control media gateway.The CBC interface uses the communication protocol between call server and media gateway, as H.248, and MGCP (MGCP) etc.

This carrying control mode has following shortcoming: a large amount of media resource data are kept at call control layer, each call control node must independently be controlled media resource, causes medium control flow very complicated (medium of for example handling the inter-network pass connect optimization problem); Different call control nodes may be controlled identical media resource simultaneously, is difficult to the Synchronous Processing media resource and connects; To call out the control of control and medium and mix, be unfavorable for that media resource control further separates; In this case, can not realize controlling and separating fully of carrying.

Summary of the invention

Be the solution the above-mentioned problems in the prior art, an object of the present invention is to provide a kind of method and apparatus of on call server, realizing media resource control, thereby on call server, realize control and separating fully of carrying.Especially, will call out control and separate, realize the control of soft switch better media resource with medium control.

Another object of the present invention is that the calling-bearing interface between call server and the media gateway is optimized, and simplifies the complexity of medium control flow in the call control layer.

A further object of the present invention is that the Synchronous Processing media resource connects in the control media resource, and can guarantee the accuracy and the reliability of connection.

According to an aspect of the present invention, a kind of method that realizes media resource control in based on the call server of soft switch has been proposed, wherein, described call server is controlled the media resource on the media gateway by gateway control protocol, described method comprises: to each Media Stream between described call server and the described media gateway, use the Leg model respectively incoming call media resource and corresponding exhalation media resource to be defined, wherein use caller LegID to identify described incoming call media resource, use called LegID to identify described exhalation media resource; By the call service function in the call server (CSF) module described caller LegID sign and called LegID are discerned and managed; A Media Gateway Controller (MGC) module is set in described call server, handles by the Media Stream that described MGC module further identifies described caller LegID and called LegID sign is identified.

According to another aspect of the present invention, a kind of call server based on soft switch has been proposed, described call server is controlled the media resource on the media gateway by gateway control protocol, described call server comprises: a call service function CSF module is used for the call control signalling stream between described call server and the described media gateway is handled; A Media Gateway Controller (MGC) module, be used for each Media Stream between described call server and the described media gateway, use the Leg model respectively incoming call media resource and corresponding exhalation media resource to be defined, wherein use caller LegID to identify described incoming call media resource, use called LegID to identify described exhalation media resource; A primitive interface that connects call service function CSF module and media gateway controller MGC module, be used to simplify in the described call server between CSF and the MGC about the processing of bearer control signalling; Wherein, described CSF module is discerned and is managed described caller LegID sign and called LegID by described MGC module definition; And further described caller LegID sign and called LegID are identified the Media Stream that is identified by described MGC module and handle.

Description of drawings

Below in conjunction with the drawings the specific embodiment of the present invention is described, thus, it is more obvious that characteristics of the present invention, advantage and beneficial effect will become, wherein:

Fig. 1 shows the schematic diagram that call server of the prior art is controlled media resource;

Fig. 2 shows the schematic diagram that call server according to the present invention is controlled media resource;

Fig. 3 shows two the Leg data structures of setting up according to the present invention on the media gateway that are distributed in; And

Fig. 4 shows GMSC Incoming side medium connection procedure.

Embodiment

Below in conjunction with the drawings preferred implementation of the present invention is described in detail.

In the prior art, because call control layer is when finishing call proceeding, also to control media resource, the defective of being brought is thus: a large amount of media resource data are kept at call control layer, each call control node must independently be controlled media resource, causes medium control flow very complicated (medium of for example handling the inter-network pass connect optimization problem); Different call control nodes may be controlled identical media resource simultaneously, is difficult to the Synchronous Processing media resource and connects; To call out the control of control and medium and mix, be unfavorable for that media resource control further separates; In this case, can not realize controlling and separating fully of carrying.

For addressing the above problem, basic thought of the present invention is to set up a kind of logical model that media resource is carried out centralized management in call server.The logical model that is appreciated that centralized management media resource designed according to this invention has versatility to soft switchcall server.Particularly, the present invention has designed a kind of method that is controlling models with Leg to realize that call server is controlled media resource on call server.

The present invention is based on the system architecture of soft switch (Softswitch), and for example 3GPP R4,3GPP R5, NGN etc. are described.Therefore, relatively, implementation method of the present invention relates to uses following agreement, and described agreement is quoted from as a reference at this:

ITU-T Q.1902.x Bearer Independent Call Control protocol(CS2)

ITU-T Q.1950 CBC protocol

ITU-T Q.1970 IP Bearer Control protocol

ITU-T Q.1990 BICC tunneling control protocol

ITU-T H.248 H.248

3GPP TS 29.232 Media Gateway Controller；Media Gateway

interface；Stage 3

3GPP TS 23.205 Bearer Independent CS Core Network-Stage 2

Wherein a kind of execution mode of the present invention is the framework that separates with carrying with the calling of BICC (Bearer Independent CallControl) and H.248 illustrates as the medium control protocol, but the present invention is not limited to this, in having the communication system of similar framework, also can use method of the present invention and realize effective control and the management of call server media resource.

At first, introduce the notion of Leg according to the present invention.Calling with a success is an example, always has Calling Side and callee side.The present invention is abstracted into two Leg with the media resource of these both sides.Identify the media resource of these calling both sides by Leg ID.Should be appreciated that, Internet protocol), (Asynchronous Transfer Mode:, and corresponding medium processing capacity is as speech coding conversion, DTMF detection, voice conferencing bridge joint, automatic speech recognition, speech-to-text conversion etc. for ATM asynchronous transfer mode), EL media resources such as (E1) media resource described here includes but not limited to IP (Internet Protocol:.Defined Leg model comprises following data structure according to the present invention, and should be understood that also can similar model constructed according to the invention:

● the relevant information of relevant MGW address is described;

● describe the dependency structure of Context content in the agreement H.248, comprise the attribute of the Context correspondence of agreement regulation;

● describe the dependency structure of Termination content in the agreement H.248, comprise the attribute of Termination correspondence in the agreement;

● other information of medium are described as the encoding list of consulting, SDP, Tunnel information etc.

In every message in the agreement H.248/Megaco, comprise one or more transaction, constitute affairs (Transaction) by " request " and " response ", each transaction comprises one or more contexts (context), and each context comprises one or more orders.Contextual definition the contact between some terminals, context is to describe the topological relation between the terminal and the parameter of medium mixing/exchange.

After introducing the Leg notion, in order to manage control Leg, increase a media gateway controller MGC (Media Gateway Controller) module on the call server newly, interface as shown in Figure 2 for the call bearer control CBC (Call Bearer Control) after the improvement.Call service function CSF (Call Service Function) is to the operation control of the paired LegID of operation control transformation of medium, and real media manipulation realizes at MGC.Thereby no longer need to preserve a large amount of media resource data at call control layer, simplified the complexity of medium control flows.

Thus, call server is realized the media resource that LegID identified is effectively managed by defined Leg and corresponding LegID thereof are discerned and manage.

Above-mentionedly realized centralized management by using, and realized to call out further separation of control and medium control, and then realized control and separating fully of carrying medium according to MGC module of the present invention.

Below specify the MGC module of setting up according to the present invention, described MGC module is a centralized control resource module, and each CSF is by carrying out media manipulation alternately with the MGC module.Particularly, MGC module according to the present invention has following function:

● the distribution of control resource (as LegID, ConfID etc.);

● by the CBC interface to the control and management of MGW media resource;

● the management of a plurality of media gateway (when for example medium connect the inter-network pass, inner attended operation between the shielding gateway); That is, MGC manages all connection end point information, intermediate ends dot information and the annexation between them.And distribute two independently LegID come presentation medium information, CSF only need manage this two LegID, and need not be concerned about concrete terminal point information.

● when handling complicated business, CSF shielding medium are connected intermediary operation.CSF only need operate Leg, need not be concerned about concrete media manipulation.Leg is to concrete media information in the MGC mapping, carries out actual medium control operation.

● process that separate calls is relevant and the incoherent process of calling (breaking away from service etc.) as MGW registration, MGW; These processes directly terminate in the MGC module, and MGC manages all MGW information, and CSF need not be concerned about.

● for CSF provides carrying control operation interface;

MGC needs to distribute interim node when doing the medium attended operation of striding media gateway.MGC need manage interim node.Simultaneously, MGC can carry out preferably MGW.For example an end point type is IP, and the gateway at another end point place is supported the IP end point, and MGC can choose two end point on the MGW.

For calling out incoherent process (breaking away from service etc. as MGW registration, MGW), the MGC module can be distributed on the module of centralized management MGW resource status calling out incoherent process.

Below specify the interface between the bearer inter-working function module (Bearer Interworking Function BIWF) according to MGC module of the present invention and MGW.

Described interface keeps the interface between original CSF and the MGW constant.Adopt CBC agreement, H.248 or the standard interface of other protocol definitions, comprise (Package), process (Transaction or Procedure) (referring to table one) etc.

The affairs of in Q.1950, using	The flow process of definition in 3GPP TS 23.205 and 23.153
		Change_Topology	Change Flow Direction changes flow path direction
Join	Join Bearer Termination
		Isolate	Isolate Bearer Termination
Establish_BNC_Notify+(tunnel)	Establish Bearer
		Prepare_BNC_Notify+(tunnel)	Prepare Bearer
Cut_Through	Change Through-Connection
		Not defined in Q.1950	Activate Interworking Function
Cut_BNC(include several procedures).	Release Bearer(Release Bearer and Release termination)
		BNC Established	Bearer Established
BNC Release	Bearer Released
		Insert_Tone	Send Tone
Insert_Annoucement	Play Announcement
		Signal Completion	Announcement Completed
Detect_Digit	Detect DTMF
		Insert_Digit	Send DTMF
Detected digit(BIWF)	Report DTMF
		Confirm_Char	Confirm Char
Modify_Char	Modify Char
		Reserve_Char_Notify	Reserve Char
BNC Modified	Bearer Modified
		Echo Canceller	Activate Voice Processing Function
BNC Connected	[No definition yet]
		BNC Modification failure	Bearer Modified Failed
Tunnel(MGC-MGW)	Tunnel Information Down
		Tunnel(MGW-MGC)	Tunnel Information Up
Insert Tone	Stop Tone
		Insert Announcement	Stop Announcement
Detect Digits	Stop DTMF Detection
		Insert Digit	Stop DTMF
Signal.Completion	Tone Completed

Below explanation is according to the interface between MGC module of the present invention and the CSF.

After introducing the MGC module, original CBC interface is transformed into internal interface, that is to say, the interface of MGC and CSF can own simple defining, need not observe H.248 or MGCP or the like agreement.As mentioned above, CSF can simply come media manipulation by control LegID, and the structure of call control layer is greatly simplified.For instance, realize, this interface can be packaged into succinct interface primitive for simplifying.

This interface described in some primitive of definition below:

● batch operation MGC-BIND:CSF gives MGC with the related media information band, indication MGC allocation medium resource.MGC and distributes LegID to identify after the media gateway Resources allocation, then LegID is returned to CSF.

● revise that (connections) operation MGC-MODIFY:CSF will call out relevant LegID and other relevant informations bring MGC, and indicate MGC make amendment medium property or connection medium.

● releasing operation MGC-UNBIND:CSF will call out relevant LegID and other relevant informations bring MGC, and make amendment medium property or connect medium of indication MGC.

Similarly, can define other operation primitive such as playback, collect the digits etc.

Fig. 3 is a pair of Leg controlling models that is distributed in two callings on the media gateway.In a pair of calling, the calling and called user may use the carrying or the resource that requires to be not quite similar, and so also just makes the calling and called user may be linked into different media gateway.Connect from medium, calling and called need to set up the Media Stream that is linked into media gateway separately, because cross over different media gateway, also need the Media Stream that connects two media gateway.

On the soft switch controlling models, the Media Stream of calling and called all is by different Context and Termination set expression.For instance, in accompanying drawing 3, Termination1 represents calling endpoint, and its medium property indicates the caller Media Stream.Termination4 represents the called end point, and its medium property is represented called Media Stream.In the identical Context1 of Termination1, end points Termination2 in the middle of setting up, in the identical Context2 of Termination4, end points Termination3 in the middle of setting up.Connection attribute between Termination2 and the Termination3 is represented the Media Stream that inter-network is closed.The bearing relation that this shows a pair of calling can be very complicated, if CSF directly manages these relations, will make operation flow complexity extremely.

The present invention independently goes out these Media Stream relations of the special organization and administration of MGC, distributes simple LegID1, and LegID2 shines upon the medium annexation of calling and called.CSF only need manage this two LegID, thinks that simply it represents the calling and called carrying, need not be concerned about the concrete beared information of its representative, and all concrete media informations are explained by MGC.

Fig. 4 connects flow process according to the solution of the present invention at the medium that GMSC Incoming side realizes.This flow process mainly shows separating of CSF and MGC function, and CSF utilizes with the primitive interface of concrete bearer independent and communicates by letter with MGC, and MGC finishes the carrying mapping, uses the CBC agreement control media gateway of standard.Concrete steps are as follows,

1) CSF receives the Initial Address message of playing a game, and uses primitive MGC_Bind_Req to MGC request Incoming bearing resource.After MGC receives request, select suitable media gateway, use standard C BC protocol command ADD to this gateway application resource.

2) gateway successfully returns bearing resource (C1 T1) gives MGC, and MGC shields concrete beared information, distributes corresponding LegID1.Use primitive MGC_Bind_Rsp (LegID1) to return to the CSF carrying.

3) CSF preserves Incoming LegID1, re-uses MGC_Bind_Req (LegID1) and applies for called bearing resource to MGC.MGC judges whether that according to Incoming information, calling features needs select different media gateway (being at same gateway in the present embodiment).Use standard A DD order to the called carrying of this gateway application.

4) gateway successfully returns bearing resource (C1 T2) gives MGC, and MGC shields concrete beared information, distributes corresponding LegID2.Use primitive MGC_Bind_Rsp (LegID2) to return to the CSF carrying.

5) CSF obtains called LegID2, and the called bearer related information of Incoming side this moment is complete, returns Adress Complete information to the Incoming far-end.

6) (LegID1 LegID2) connects calling and called to the MGC request to CSF use MGC_Modify_Req.MGC shines upon LegID1, and (C1, T1), (C2 T2), analyzes its concrete medium stream information to LegID2, and the MOD order request media gateway of use standard C BC agreement connects T1 and the T2 among the C1 to concrete beared information.

7) media gateway is successfully returned connection, and MGC returns success and connects MGC_Modify_Rsp to CSF.This moment, the calling and called beared information was complete, and CSF returns Anwser message to the Incoming far-end, and phone is set up successfully.

8) the Incoming far-end is sent out Release and is required to take out stitches to CSF.CSF removes request MGC_Unbind_Req (LegID1) to MGC application carrying.MGC analyze LegID1 mapping relations (C1, T1) and called carrying (C1, T2), this moment, calling and called still were in connection status, MGC uses standard C BC interface to send out to media gateway to disconnect calling and called carrying connection request.Successfully return the back sending out removing end points T1 request, finish the work of taking out stitches.

Below in conjunction with the drawings the method and the corresponding apparatus of media resource control of realizing in the call server of soft switch of the present invention set forth, but the present invention is not limited to this.One skilled in the art will appreciate that according to the principle of the invention, can make various modifications, improvement, and do not break away from the enclose scope of claim of the present invention the present invention.

Claims (12)

1, a kind of method that in based on the call server of soft switch, realizes media resource control, wherein, described call server is controlled the media resource on the media gateway by gateway control protocol, and described method comprises:

To each Media Stream between described call server and the described media gateway, use the Leg model respectively incoming call media resource and corresponding exhalation media resource to be defined, wherein use caller LegID to identify described incoming call media resource, use called LegID to identify described exhalation media resource;

By the call service function CSF module in the call server described caller LegID sign and called LegID are discerned and managed;

A media gateway controller MGC module is set in described call server, further the Media Stream that is identified by described caller LegID sign and called LegID sign is handled by described MGC module.

2, according to the method that in the call server of soft switch, realizes media resource control of claim 1, wherein, described MGC module is handled at least a media resource among IP, ATM, the E1, so that at least a medium processing capacity of corresponding speech coding conversion, DTMF detection, voice conferencing bridge joint, automatic speech recognition, speech-to-text conversion is controlled.

3, according to the method that in the call server of soft switch, realizes media resource control of claim 1, also be included in the step of adding following at least a kind of information in the media resource of described use Leg model identification, described information comprises:

The relevant information of related media gateway address;

The dependency structure of context Context in the associated gateway control protocol comprises the attribute of the Context correspondence of described agreement regulation;

The dependency structure of Termination content in the associated gateway control protocol comprises the attribute of Termination correspondence in the described agreement; And

The relevant information of described media resource.

4, according to the method that in the call server of soft switch, realizes media resource control of claim 1, further comprise:

By the operation of the mutual execution between CSF and the MGC to media resource, the operation of wherein said MGC comprises:

The distribution of control resource;

Control the CBC interface to the control and management of media gateway MGW media resource by call bearer;

The management of a plurality of media gateway;

CSF shielding medium are connected intermediary operation;

Process that separate calls is relevant and the incoherent process of calling; And

For CSF provides carrying control operation interface.

5, according to the method that in the call server of soft switch, realizes media resource control of claim 1, further comprise:

Between described MGC module and media gateway, adopt the CBC agreement, H.248 or the standard interface of other protocol definitions communicate.

6, according to the method that in the call server of soft switch, realizes media resource control of claim 1, further comprise: between described MGC module and CSF, be provided with interface, interface package interface primitive between described MGC module and CSF is to become the primitive interface with concrete bearer independent, so that CSF utilizes described primitive interface with concrete bearer independent to communicate by letter with MGC, identify media resource is operated by controlling described caller LegID sign and called LegID, wherein said primitive comprises:

The batch operation MGC-BIND of indication MGC allocation medium resource;

Make amendment medium property or connect the modification/attended operation MGC-MODIFY of medium of indication MGC;

Make amendment medium property or connect the releasing operation MGC-UNBIND of medium of indication MGC.

7, a kind of call server based on soft switch, described call server is controlled the media resource on the media gateway by gateway control protocol, and described call server comprises:

A call service function CSF module is used for the call control signalling stream between described call server and the described media gateway is handled;

A media gateway controller MGC module, be used for each Media Stream between described call server and the described media gateway, use the Leg model respectively incoming call media resource and corresponding exhalation media resource to be defined, wherein use caller LegID to identify described incoming call media resource, use called LegID to identify described exhalation media resource;

A primitive interface that connects call service function CSF module and media gateway controller MGC module, be used in the described call server between CSF and the MGC about the processing of bearer control signalling;

Wherein, described CSF module is discerned and is managed described caller LegID sign and called LegID by described MGC module definition; And

Handle by the Media Stream that described MGC module further identifies described caller LegID and called LegID sign is identified.

8, according to the call server based on soft switch of claim 7, wherein, described MGC module is handled at least a media resource among IP, ATM, the E1, so that at least a medium processing capacity of corresponding speech coding conversion, DTMF detection, voice conferencing bridge joint, automatic speech recognition, speech-to-text conversion is controlled.

9, according to the call server based on soft switch of claim 7, wherein, use the media resource of Leg model identification to comprise following a kind of information at least:

The relevant information of related media gateway address;

The dependency structure of context Context in the associated gateway control protocol comprises the attribute of the Context correspondence of described agreement regulation;

The dependency structure of Termination content in the associated gateway control protocol comprises the attribute of Termination correspondence in the described agreement; And

The relevant information of described media resource.

10, according to the call server based on soft switch of claim 7, by the operation of the mutual execution between CSF and the MGC to media resource, the performed operation of wherein said MGC further comprises:

The distribution of control resource;

By the CBC interface to the control and management of media gateway MGW media resource;

The management of a plurality of media gateway;

CSF shielding medium are connected intermediary operation;

Process that separate calls is relevant and the incoherent process of calling; And

For CSF provides carrying control operation interface.

11, according to the call server based on soft switch of claim 7, adopt between wherein said MGC module and the media gateway CBC agreement, H.248 or the standard interface of other protocol definitions communicate.

12, according to the call server based on soft switch of claim 7, wherein, interface between described MGC module and the CSF also is arranged to package interface primitive, so that CSF utilizes with the primitive interface of concrete bearer independent and communicates by letter with MGC, come media resource is operated by controlling described LegID, wherein said primitive comprises:

The batch operation MGC-BIND of indication MGC allocation medium resource;

Make amendment medium property or connect the modification/attended operation MGC-MODIFY of medium of indication MGC;

Make amendment medium property or connect the releasing operation MGC-UNBIND of medium of indication MGC.

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