CN101453470A - Session description protocol capability information obtaining method, system and network entity - Google Patents

Abstract

The present invention relates to communication technology, in particular to a method, system and network entity for acquiring session description protocol capability information, which are used to solve the problem in the prior art that one communication party cannot obtain the other party's session description protocol capability information. The technical scheme of the present invention realizes that one communication party obtains its session description protocol capability information from the other party through the message interaction between the communication parties, especially when it is applied under the H.248 protocol, by extending the corresponding attribute parameters, the media can be conveniently realized. The gateway controller obtains the corresponding SDP capability information between the media gateways.

Description

Session description protocol capability information acquisition method, system and network entity

technical field

The present invention relates to communication technology, in particular to a method, system and network entity for acquiring session description protocol capability information.

Background technique

MGC (Media Gateway Controller, Media Gateway Controller) and MG (Media Gateway, Media Gateway) are two key components in the packet network. The MGC is responsible for the call control function, and the MG is responsible for the service bearer function, thereby realizing the separation of the call control plane and the service bearer plane, thereby fully sharing network resources, simplifying equipment upgrades and service expansion, and greatly reducing development and maintenance costs. For example, as shown in Figure 1, it is a schematic diagram of networking between MG and MGC in NGN (Next Generation Network, next-generation network), wherein, the communication protocol between MG is RTP (Real-time Transport Protocol, real-time transport protocol) protocol; MG and The currently widely used communication protocols between MGCs include H.248/MeGaCo (Gateway Control Protocol, Gateway Control Protocol) and MGCP (MediaGateway Control Protocol, Media Gateway Control Protocol). Among them, MGCP version 1 was formulated by IETF (Internet Engineering Task Force, Internet Engineering Task Force) in October 1999 and revised in January 2003, H.248/MeGaCo version 1 was developed by IETF and ITU (International Telecommunications Union, International Telecommunications Union, ) was jointly formulated in November 2000 and revised in June 2003, H.248 version 2 was formulated by ITU in May 2002 and revised in March 2004, H.248 version 3 was formulated by ITU in September 2005 .

Taking H.248 as an example, various resources on the MG are abstracted as Tennination. Terminals are further divided into physical (Physical) terminals and temporary (Ephemeral) terminals. The former represents some physical entities with semi-permanent existence, such as TDM (Time Division Multiplex, time division multiplexing) channels, etc., and the latter represents some temporary applications that are released after use. public resources, such as RTP streams, etc. In addition, the Root terminal represents the MG as a whole. The combination between terminals is abstractly represented as a context (Context). A context can contain multiple terminals, so topology (Topology) is used to describe the relationship between terminals. For terminals that have not yet been associated with other terminals, they are contained by a special context called a Null context.

Based on this abstract model of the protocol, the connection of the call is actually an operation on the terminal and the context. This operation is accomplished through a command (Command) request (Request) and a response (Reply) between the MGC and the MG. Command types include Add, Modify, Subtract, Move, AuditValue, AuditCapabilities, Notify, and ServiceChange. Command parameters, also known as descriptors (Descriptor), are classified into properties (Property), signals (Signal), events (Event), statistics (Statistic), etc. Parameters with business relevance are logically aggregated into packages.

H.248 uses Local (local) and Remote (remote) descriptors to negotiate media parameters, where the Local descriptor defines the parameters of the media received by the local end, and the Remote descriptor defines the parameters of the remote received media , such as receiving address, receiving port, media type, etc. H.248 uses the SDP (Session Description Protocol) based on RFC2327 formulated by IETF to describe these media parameters by default in the Local and Remote descriptors. However, IETF has formulated RFC3266, which is an update to RFC2327 in order to support IPv6, and IETF has revised SDP in the newly formulated RFC4566, which leads to changes in protocol syntax.

As RFC3266 and RFC4566 will also be applied in H.248, MGs that implement these different RFCs related to SDP will be endowed with different SDP capabilities, including possible supported SDP parameters and possible values of these parameters. The MGC needs to understand these SDP capabilities of the MG in order to effectively use these capabilities in the control of the MG. Although the current H.248 protocol allows the MGC to audit the Local and Remote descriptors on the MG, it does not provide a mechanism for the MGC to obtain information about the SDP capabilities of the MG.

Contents of the invention

The present invention provides a method, system and network entity for acquiring session description protocol capability information to solve the problem in the prior art that one party in communication cannot obtain the other party's session description protocol capability information.

The present invention provides a method for acquiring session description protocol capability information, including:

The first network entity requests the second network entity for the session description protocol capability information of the second network entity;

In response to the request, the second network entity returns the local SDP capability information to the first network entity.

In the method, the SDP capability information includes an SDP attribute parameter and a value corresponding to the SDP attribute parameter.

Further, the method further includes the following step: the second network entity saves the received SDP capability information of the second network entity locally.

Wherein, the communication between the first network entity and the second network entity is through the H.248 protocol.

Under the H.248 protocol, the request sent by the first network entity to the second network entity may be an audit command request carrying attribute parameters respectively corresponding to the SDP capabilities to be requested by the first network entity;

According to the audit command request, the second network entity returns the local SDP capability information to be requested by the first network entity in a command response of the command request to the first network entity.

Under the H.248 protocol, the request sent by the first network entity to the second network entity may be an audit command request carrying attribute parameter flags corresponding to requesting all session description protocol capabilities;

In response to the audit command request, the second network entity returns all SDP capability information of the local end in a command response of the command request to the first network entity.

Wherein, an attribute parameter corresponding to the SDP capability is set in the command response, and the SDP capability information of the second network entity is set as a value of the corresponding attribute parameter.

The present invention also provides a system for acquiring SDP capability information, including a first network entity and a second network entity, wherein:

The first network entity includes: a module for requesting the second network entity's SDP capability information from the second network entity;

The second network entity includes: a module for returning the local SDP capability information to the first network entity in response to the request of the first network entity.

Further, the first network entity further includes: a first storage module storing the SDP capability information of the second network entity.

Further, the first network entity further includes a first transceiver module, which sends the request;

The second network entity further includes: a second transceiver module, configured to receive the request and send the information.

Wherein, the first network entity is a media gateway controller, the second network entity is a media gateway, and the media gateway controller and the media gateway communicate through the H.248 protocol.

The beneficial effects of the present invention are as follows:

A method and system for acquiring session description protocol capability information provided by the present invention realizes one communication party obtaining its session description protocol capability information from the other party through message interaction between the two parties, especially when it is applied under the H.248 protocol, through By extending the corresponding attribute parameters, it is convenient for the media gateway controller to obtain the corresponding session description protocol capability information between the media gateways.

Description of drawings

Figure 1 is a schematic diagram of networking of MG and MGC in NGN;

FIG. 2 is a schematic flowchart of the first method for acquiring session description protocol capability information according to the present invention;

FIG. 3 is a schematic diagram of a main structure of the SDP capability information acquisition system and network entities of the present invention.

Detailed ways

A method for acquiring session description protocol capability information provided by the present invention includes:

The first network entity requests the second network entity's session description protocol capability information from the second network entity;

In response to the request, the second network entity returns the local SDP capability information to the first network entity.

When the first network entity and the second network entity communicate through the H.248 protocol, the SDP parameters defined in RFC4566 can be defined as a H.248 Registry type in the IANA (Internet Assigned Numbers Organization) Extended property (Property) parameters. These SDP parameter types include:

●Transport protocol (proto)

●Bandwidth description (bwtype)

●Network type (nettype)

●Address type (addrtype)

● key (enckey)

●Session-level attribute domain (att-filed(session level))

●Session and media level attribute domain (att-field(both session and media level))

●Only media level attribute field (att-field(media level only))

● Unknown level attribute field (att-field(unknown level)).

The above attribute parameters respectively represent values that can be associated with the corresponding registration types, and the data type is a string (String) list, which is set in the terminal state and is a read-only parameter.

As shown in Figure 2, the main process of realizing the above-mentioned method of the present invention under the H.248 protocol includes the following steps:

Step S201, the first network entity sends an audit command request to the second network entity, and the audit command request carries attribute parameters corresponding to the above-mentioned SDP capabilities to be requested by the first network entity;

Under the H.248 protocol, the request sent by the first network entity to the second network entity may be an audit command request carrying attribute parameters corresponding to the SDP capabilities that the first network entity wants to request; the second network entity According to the audit command request, the SDP capability information of the local end to be requested by the first network entity is carried in a command response of the command request and returned to the first network entity.

Under the H.248 protocol, the request sent by the first network entity to the second network entity may be an audit command request carrying an attribute parameter flag representing all SDP capabilities corresponding to the request, for example, carrying a wildcard; the first In response to the audit command request, the second network entity returns all SDP capability information of the local end in a command response of the command request to the first network entity.

Step S202. According to the audit command request, the second network entity returns the SDP capability information of the local end that the first network entity wants to request in the command response of the command request to the first network entity;

Wherein, the attribute parameters corresponding to the above-mentioned SDP capabilities to be requested by the first network entity are set in the command response, and the SDP capability information of the second network entity is respectively set as the value of the corresponding attribute parameters; or according to the wildcard, the command The response is set with attribute parameters and corresponding values corresponding to all SDP capabilities supported by the second network entity, and values corresponding to attribute parameters not supported by the second network entity are empty.

Step S203, the first network entity saves the received SDP capability information of the second network entity locally.

An application scenario of the above technical solution is: the first network entity is the MGC, and the second network entity is the MG. Typically, in order to determine the SDP capability of the MG, including the SDP parameters that may be supported and the possible values of these parameters, the MGC should Send an audit command request, such as an audit value (AuditValue) command request, to the MG for the above attribute parameters, and then the MG will return the value that may be associated with each audited attribute parameter to the MGC in a corresponding command response. The MGC can also use a wildcard (Wildcard) to audit all the above attribute parameters at the same time. If the MG does not support the SDP parameter corresponding to an audited attribute parameter, the value list that may be associated with the attribute parameter returned to the MGC is empty. Therefore, the MGC can obtain the SDP capability of the MG by auditing these attribute parameters.

For example, the package to which these extended attribute parameters belong is named SDP Capability (SDP Capability) package, the attribute parameter corresponding to the transmission protocol (proto) registration type is also named transmission protocol (proto), and the address type (addrtype) registration type is corresponding to The attribute parameter of is also named address type (addrtype). The MGC sends to the MG the audit value (AuditValue) command request for the transmission protocol (proto) and address type (addrtype) attribute parameters of the SDP Capability (SDP Capability) packet, and the MG responds with the transmission protocol supported by itself in the corresponding command response The possible values of RTP and TCP as the transmission protocol (proto) attribute parameter are put in a list, and the address type IP4 supported by itself is put in a list as the possible value of the address type (addrtype) attribute parameter, and returned together to MGC. From this, the MGC can learn that the transmission type supported by the MG is RTP or TCP, and the address type is IPv4.

As shown in FIG. 3 , the present invention also provides a system for acquiring SDP capability information, including a first network entity 300 and a second network entity 400, wherein:

The first network entity 300 includes: a first transceiver module 301;

The first network entity 300 also includes: a module for requesting the second network entity's SDP capability information from the second network entity through the first transceiver module 301, such as the request module 302 in FIG. 3 ;

The first network entity 300 also includes: a first storage module 303 for saving the SDP capability information of the second network entity;

The second network entity 400 includes: a second transceiver module 401;

The second network entity 400 also includes: in response to the request of the first network entity 300, a module that returns the local SDP capability information to the first network entity 300 through the second transceiver module 401, such as the response module shown in FIG. 3 402.

Wherein, the above-mentioned first network entity is a media gateway controller, the second network entity is a media gateway, and the media gateway controller and the media gateway communicate through the H.248 protocol.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (18)

1, a kind of session description protocol capability information obtaining method is characterized in that, comprises the steps:

First network entity is to the session description protocol capability information of described second network entity of the second network entity request;

Described second network entity response described request returns to described first network entity with the session description protocol capability information of local terminal.

2, the method for claim 1 is characterized in that, described session description protocol capability information comprises the session description protocol parameters supported and the value of this session description protocol parameters correspondence.

3, the method for claim 1 is characterized in that, passes through H.248 protocol communication between described first network entity and second network entity.

4, method as claimed in claim 3 is characterized in that:

The request that described first network entity sends to second network entity is the audit command request that carries the session description protocol capability information of the first network entity desire request;

Described second network entity is according to described audit command request, the session description protocol capability information of the local terminal of the first network entity desire request is carried in the command response of this command request and returns to described first network entity.

5, method as claimed in claim 4 is characterized in that, is provided with the corresponding respectively property parameters of described session description protocol capability in the described command request.

6, method as claimed in claim 3 is characterized in that:

The request that described first network entity sends to second network entity is the audit command request that carries the sign of all session description protocol capability information of representative request;

Described second network entity responds described audit command request, all session description protocol capability information of local terminal is carried in the command response of this command request and returns to described first network entity.

7, as claim 4 or 6 described methods, it is characterized in that, be provided with the corresponding respectively property parameters of described session description protocol capability in the described command response, the session description protocol capability information of described second network entity is set to the value of corresponding property parameters.

8, method as claimed in claim 7 is characterized in that, in the described command response, the value of the unsupported property parameters correspondence of second network entity is empty.

9, the method for claim 1 is characterized in that, described first network entity is a Media Gateway Controller, and described second network entity is a media gateway.

10, a kind of session description protocol capability Information Acquisition System comprises first network entity and second network entity, it is characterized in that:

Comprise in described first network entity: to the module of the session description protocol capability information of described second network entity of the second network entity request;

Comprise in described second network entity: respond the request of described first network entity, the session description protocol capability information of local terminal is returned to the module of described first network entity.

11, system as claimed in claim 10 is characterized in that, also comprises in described first network entity: first memory module of preserving the session description protocol capability information of described second network entity.

12, system as claimed in claim 11 is characterized in that:

Comprise also in described first network entity that first transceiver module sends described request;

Also comprise in described second network entity: second transceiver module receives described request and sends described information.

13, system as claimed in claim 10 is characterized in that, described first network entity is a Media Gateway Controller, and described second network entity is a media gateway, passes through H.248 protocol communication between this Media Gateway Controller and the media gateway.

14, a kind of network entity comprises first transceiver module, it is characterized in that, described network entity also comprises: by the module of described first transceiver module to this opposite end session description protocol capability information of Correspondent Node request.

15, network entity as claimed in claim 14 is characterized in that, also comprises in the described network entity: first memory module of preserving the session description protocol capability information of described second network entity.

As claim 14 or 15 described network entities, it is characterized in that 16, described network entity is a Media Gateway Controller.

17, a kind of network entity comprises second transceiver module, it is characterized in that, described network entity also comprises: the module that sends the session description protocol capability information of local terminal by described second transceiver module.

18, network entity as claimed in claim 17 is characterized in that, described network entity is a media gateway.

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