WO2007019777A1

WO2007019777A1 - A session establish method and a session control node

Info

Publication number: WO2007019777A1
Application number: PCT/CN2006/001855
Authority: WO
Inventors: Ying Wang; Peng Wang; Baofeng Zhang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-08-16
Filing date: 2006-07-26
Publication date: 2007-02-22
Also published as: CN1889565B; CN1889565A

Abstract

A session establish method and a session control node can improve the efficiency of the session establish with the ensured most success. In present invention, when the session control node with media control ability transmits the initial session establish request massage, the extra media ability provided by the gateway of the node is added into the calling terminal media ability set, and the added media ability can be exchanged with the intrinsic ability in the media ability set by the gateway. When the reply massage is transmitted, if the media ability with highest priority level in the called terminal media ability set in the massage should be provided by the gateway of the node, the priority level of the media ability which has the highest priority level in the primary calling terminal media ability set can be set as the highest priority level, and said media ability can be exchanged with this media ability.

Description

Session establishment method and session control node

Technical field

The present invention relates to a communication technology, and more particularly to a session establishment method and a session control node in a case where a terminal capability of a SIP (Session Initiation Protocol) domain is not matched. BACKGROUND OF THE INVENTION The Session Initiation Protocol is a "standard for Voice over Internet Protocol (VoIP)" released by the Internet Engineering Task Force (IETF) in March 1999.

The SIP signaling protocol is used to initiate, manage, and terminate voice and video sessions in a packet network, specifically to generate, modify, and terminate sessions between one or more participants. SIP is an integral part of the IETF multimedia data and control architecture and is therefore associated with many other IETF protocols, such as the Real Time Transfer Protocol (RTP) and the Session Description Protocol (Session Description Protocol). "SDP") and so on.

SIP mainly provides five aspects related to session establishment and termination:

(1) User location: decision of the terminal system used for communication;

(2) User availability: the decision of the called party to participate in the communication; (3) User capabilities: the decision of the media and media parameters used;

(4) Session establishment: "ringing,,, and establishment of call and callee session parameters;

(5) Session management: including transferring and terminating sessions, modifying session parameters, and calling services.

SIP has two types of messages:

(1) Request: A message sent from the client to the server.

(2) Response: A message sent from the server to the client. The request message includes:

INVITE: Initial call.

ACK: Confirm the final response of the INVITE.

BYE: Terminate the call.

CANCEL: Undo search and ring.

OPTIONS: Query the other party's capabilities.

REGISTER: Register a location service.

INPO: Sends information in a session without changing the session state.

PRACK: Same as ACK, but for temporary response.

SUBSCRIBE: This method is used to subscribe to notifications of changes in status to remote endpoints.

NOTIFY: This method sends a message to inform the subscriber of the change in the state of the reservation.

UPDATE: Allows the client to update the parameters of a session without affecting the current state of the session.

MESSAGE: Instant messaging by hosting instant messaging content in its request body.

REFER: Its function is to instruct the recipient to contact a third party by using the contact address information provided in the request. The response message contains a numeric response code. The SIP response code set is based in part on the Hyper Text Transfer Protocol ("HTTP") response code. There are two types of responses: Temporary Response (1XX): The temporary response is used by the server to indicate the process, but does not terminate the SIP transaction. Final response (2XX, 3XX, 4XX, 5XX, 6XX): Final response to terminate SIP Transaction. The SIP that has become the mainstream protocol for the packet domain session service requires the two parties to carry the SDP description through the SIP protocol to negotiate the media capabilities. This is because in the packet-based network-based session service, the two parties must be able to perform media interaction, including media codec format, IP protocol version (IPv4/IPv6), and receiving IP address and port. The number of packets, the length of the package, etc., the negotiation is successful, and the media capabilities of both sides of the session are the same, and the interaction of the media streams is possible. This media negotiation process generally follows the Offer/Answer mode. However, when there is no intersection between the terminal capabilities of the two parties in the packet domain session, the called side will return 488 (Not Acceptable Here) or 606 (Not Acceptable), indicating that the called terminal does not support the media capability of Offer, and the call will be removed, the session will be The establishment was not successful. The process of the call failure due to the mismatch of the capabilities of the SIP terminal is as shown in FIG. 1. The first SIP server is the server to which the user of the first device terminal (TE, Terminal Equipment) belongs, and the second SIP server is the user of the second device terminal. server. In the steps 101 to 103, the SIP Invite message sent by the first device terminal is routed to the second device terminal by using the first SIP server and the second SIP server. Subsequently, the second device terminal determines the media capability and the content provided by the first terminal. The capability of the terminal cannot be matched; in steps 104 to 106, the 488 message sent by the second device terminal is routed to the first device terminal by the second SIP server and the first SIP server; Steps 107 to 109, the ACK message sent by the first device terminal Routing to the second device terminal via the first SIP server and the second SIP server. It can be understood that the middle may also be routed through other network entities, which will not be described here. Currently, in the case that the terminal capability (for example, the codec capability) cannot be matched, the service call session control function (Serving CSCF, referred to as "S-CSCF") that is called by the called user triggers the service to the application server (AppUcation Server, referred to as "AS"), the resource provided by the Media Resource Function Controller ("MRFC") is called by the AS to complete the codec conversion between the calling and the called, wherein the MRFC controls the media resource function processor (Multimedia The Resource Function Processor, called "MRFP", implements media capabilities. The specific process is shown in FIG. 2, where steps 201 to 203 are that the calling user initiates the initial call, but because the media capability of the called user does not match the media capability 1 provided by the calling user, the AS is triggered by the S-CSCF. Steps 205 to 209 are a process in which the AS initiates a call to the called user and learns from the returned response of the called user that the media capability supported by the called user is 2. Steps 212 to 217 are processes in which the AS calls the MRFC to apply for a media resource for the called user. Steps 218 to 225 are processes for the AS to negotiate with the called user. Since the AS already knows the media capabilities supported by the called user, the negotiation must be successful. Steps 226 to 229 are processes in which the AS calls the MRFC to apply for the media resource for the calling user. Steps 231 to 235 are the process of the capability negotiation between the AS and the calling user. Since the AS already knows the media capabilities supported by the calling user, Therefore the consultation must be successful. After the AS returns a response to the MRFC through the S-CSCF (step 236), the quality of service negotiation process of the primary and the called user is performed. It can be seen that in the prior art, the AS and the called user are respectively negotiated with the media capabilities by the AS, so that the calling and called users can establish a call. That is, the call is divided into two segments from the session control layer. The previous segment is from the calling user to the AS, and the latter segment is from the AS to the called user. The AS works in the Back to Back User Agent (B2BUA) mode. The media stream is also divided into two segments, the previous segment from the calling terminal to the MRFP, and the latter segment from the MRFP to the called terminal. In the actual application, the above solution has the following problems: In the case that the terminal capabilities of the primary and the called user do not match, the entire session process has many steps, and the session establishment time is relatively long.

The main reason for this situation is that the entire session must be triggered by the S-CSCF, the call is established in two segments, the media negotiation is also carried out separately, and the mediation between the calling terminal/called terminal and the MRPP is required. The AS is divided into two segments to negotiate with the calling/called user and the MRFC, respectively. As can be seen from Figure 2, the Offer/Answer negotiation is performed four times during the session establishment process of the primary and called users, and the Offer/Answer negotiation has a long route and many intermediate nodes, so the Offer/Answer negotiation The efficiency is lower. In addition, the AS requests two resources for the called user and the calling user respectively. Therefore, the time ratio of session establishment Longer.

SUMMARY OF THE INVENTION The present invention provides a session establishment method and a session control node, which improves session establishment efficiency on the premise of maximizing the success of a session. The present invention provides a session establishment method, including the following steps: When a session control node having a media control capability forwards a request to establish a session message, the parameter of the media capability additionally provided by the gateway controlled by the node is added to the message. The media capabilities of the calling terminal are concentrated, wherein the newly added media capability is that the original media capability is not concentrated but can be converted with the original media capability centralized media capability through the gateway; the session control node transmits the pair backwards. If the message of the session establishment media message carrying the response message of the called terminal media capability set is clear, if the first media capability with the highest priority of the called terminal media capability concentration of the called terminal is to be provided by the gateway controlled by the local node, Selecting a second media capability with the highest priority and being mutually convertible by the gateway and the first media capability, and recording the highest priority media capability in the response message. Set to the second media capability. The message requesting to establish a session and the response message thereof are session initiation protocol messages; in the message requesting to establish a session and the response message thereof, the media capability set of the primary and the called terminal is respectively described by a session description protocol. Further in the method, the message requesting to establish a session is an "Invite" message; the response message is a "180 Ringing" or "183 Session Progress" message. In addition, in the method, the session control node with media control capability may be a media resource function controller;

'The gateway may be a media resource function processor. In addition, in the method, when the session control node transmits a response message to the message requesting to establish a session, if the media capability of the called terminal carried by the response message is determined The first media capability with the highest priority should be provided by the gateway controlled by the node, and further includes the following steps: deleting or placing the media capability of the called terminal with the media capability other than the second media capability Lower priority. In addition, in the method, the priority of the newly added media capability is lower than the priority of each media capability of the original calling terminal media capability set in the message requesting the session establishment. In addition, in the method, when the session control node transmits a response message to the message requesting to establish a session, if it is determined that the media content of the called terminal with the highest priority of the media content of the called terminal is It should be provided by the gateway controlled by the local node, and further includes the following steps: requesting the gateway to reserve resources for implementing conversion between media corresponding to the first and second media capabilities. In addition, in the method, when the session is established, the route of the calling terminal user to the called terminal user may pass through one or more of the session control nodes with media control capabilities. In addition, in the method, when the session control node transmits a response message to the message requesting to establish a session, if it is determined that the media content of the called terminal with the highest priority of the media content of the called terminal is It should not be provided by the gateway controlled by the node, and further includes the following steps: transparently transmitting the called terminal media capability set, or at least partially according to the record, the called terminal media capability should be centralized by each node provided by the node The media ability is removed and passed down. In addition, in the method, when the media stream of the session is established, the gateway forwards the media corresponding to the second media capability to the media corresponding to the first media capability, and The media corresponding to one media capability is converted into the media corresponding to the second media capability. The present invention also provides a session control node, including: a media capability adding unit, configured to additionally provide media capabilities of a gateway controlled by the node The mediation capability of the calling terminal carried in the message that is added to the forward-delivered request establishment session; the additional provided media capability is that the original calling terminal media capability is not concentrated but can pass the gateway and the original calling terminal media capability The first media capability determining unit is configured to determine whether the first media capability with the highest media priority of the called terminal media capability set by the response message sent by the forward transmission of the node should be controlled by the local node. Providing: a second media capability setting unit, configured to: when the first media capability determining unit determines to be YES, select the highest priority from the foregoing original calling terminal media capability set, and pass the gateway and the first media capability The mutually converted second media capability sets the highest priority media capability in the aforementioned response message to the second media capability. The session control node further includes: a priority setting unit, configured to: when the media capability adding unit adds the media capability additionally provided by the gateway controlled by the node to the media capacity of the calling terminal carried by the message, The priority of the additionally provided media capabilities is lower than the priority of the media capabilities of the original calling terminal media capability set in the message. The session control node further includes: a media capability processing unit, configured to determine, by the first media capability determining unit, that the first media capability with the highest media priority of the called terminal carried by the response message is controlled by the local node When the gateway is provided, the media capabilities of the called terminal media capability carried in the response message are deleted or placed at a lower priority than the media capabilities of the second media capability. The session control node further includes: a called terminal media capability set delivery unit, configured to: in the first media capability determining unit, determine, by the first media capability determining unit, the first media capability with the highest media priority of the called terminal carried by the response message When the gateway controlled by the local node is not provided, the media capability set of the called terminal is transparently transmitted, or the media capability set of the called terminal is at least partially deleted, and the media capabilities provided by the local node are transmitted. The session control node further includes:

a gateway reservation resource requesting unit, configured to: when the first media capability determining unit determines that the first media capability with the highest priority of the called terminal media capability set carried by the response message is to be provided by the gateway controlled by the local node, The gateway requests the reserved resource to implement the conversion between the media corresponding to the first and second media capabilities. The session control node is a media resource function controller. The session control node is set in a server to which the end user belongs. In the present invention, the session control node having the media control capability adds the media capability provided by the local gateway to the media capability set of the calling terminal of the message when the initial session establishment request message is delivered, and the added media capability can pass through the gateway and the media. The original capabilities of the capability set are mutually converted. When the response message is delivered, if the media capability with the highest priority of the media capacity of the called terminal of the message should be provided by the gateway of the node, the media capability can be converted with the media capability. The priority of the media capability with the highest priority in the mediation of the calling terminal media capability is set to the highest. Therefore, in the case that the session terminal capability set does not match, the solution can fully utilize the network resources to ensure that the session can be successfully established, and the session establishment efficiency is relatively high. Compared with the prior art, the embodiment of the present invention improves the session establishment efficiency from three aspects: First: the present invention only performs one Offer/Answer negotiation, while in the prior art, there are four Offer/Answer negotiations, and Offer The /Answer negotiation is less efficient (because the Offer/Answer negotiation has a longer route and more intermediate nodes), so this has a greater effect on efficiency. Second, the present invention does not re-initiate the call, but only performs the modification of the media capability set on the transmitted related message, and the modification is transparent to other nodes in the route as well as the master and the called terminal. In another aspect, When upgrading an existing network to apply the present invention, the upgrade is limited to the session control node itself with media control capability, and other nodes in the network do not need to be upgraded. Level

Third, the present invention only applies for resources once to the gateway, and applies resources for media conversion in both directions in one application, while the prior art applies twice.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of message interaction in a prior art in which a SIP terminal capability mismatch causes a call to fail; FIG. 2 is a schematic diagram of message interaction in the prior art to maximize the success of a session; FIG. 3 is a session establishment method according to the present invention; Schematic diagram of message interaction.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be further described in detail below with reference to the accompanying drawings. In the case that the terminal capabilities cannot be matched, the present invention performs media conversion by means of a media gateway in the network, and adapts the capabilities of both parties. The media gateway can implement functions including codec conversion, rate adaptation, etc., and is controlled by the network session layer control node to perform these functions. According to the principle of the session establishment method of the present invention, in the session, when the originating terminal carries its own media capability description through the initial session establishment request message to the session control node having the media control capability, the session control node compares the originating terminal. The ability and the ability of the media gateway to add the ability of the media gateway to meet the following conditions in the message media capability description to the next hop: Condition 1: The originating terminal does not have the capability of the media gateway; Condition 2: For the match The ability of condition 1, while the media gateway is also able to provide its mutual conversion with at least one of the capabilities of the previous segment of the network and the originating terminal. For example: originating terminal and previous segment network support capabilities 1, 2, 3, media gateway additional support capabilities 4, 5, while the media gateway can support the conversion of capability 4 and capabilities 1, 2, 3, but does not support Ability 5 and ability 1, 2, 3 conversion, so only capability 4 can be added to the media capability description. To ensure that the called terminal preferentially selects the capabilities supported by the calling terminal when selecting the matching capability, When the session control node adds the capability parameter in the media capability description, the capability provided by the media gateway should be lower than the capability provided by the calling terminal. In the route where the calling terminal calls the called terminal, there may be multiple session control nodes capable of controlling the media gateway, and each node may add the capability that satisfies the conditions 1 and 2 to the media capability description and transmit the same. The session control node should be able to record which capabilities in the media capability description are provided by the media gateway controlled by the node, and which are provided by the previous segment network and the originating terminal. When the session establishment information (for example, the Invite message in the SIP domain) arrives at the called terminal, the Offer media capability set provided to the called terminal is already the sum of the capabilities that the originating terminal and the transit network entity can provide, and the maximum guarantee is provided to the master. The called ability negotiation can be successful. When the called terminal gives the media capability set Answer of the called terminal according to the media capability set and priority arrangement provided in the forward direction, the session control node determines whether the highest priority media capability given in the Answer is based on the previous record. Provided by the media gateway controlled by the session control node. If yes, you need to control the media gateway to provide two media conversion capabilities. The two media are: Media 1: This session controls the highest priority media capability in the Answer received by the node. Media 2: The highest priority of the Offer received by this control node is the ability to convert media with Media 1. At the same time, when the session control node passes the Answer capability set in the backward direction, the description of the media 2 is placed in the highest priority in the media capability description, and the description of other media capabilities in the received Answer can be placed after the description of the media 2 , can also be deleted. If no, the session control node does not need to do the media gateway control operation, directly transparently transmits the received Answer media capability description, and can also set the capability added by the session control node when sending the offer forward in the received Answer media. The capability description is deleted and sent out. The specific process for implementing the above inventive principles will be further described in detail below with reference to FIG. It should be noted that, in the session establishment method of the embodiment of the present invention, TE1, SCN1, SCN3, GW, SCN2, and TE2 are involved. SCN1 is a server to which the SIP terminal TE1 user belongs (for example, S-CSCF); SCN2 is a server to which the SIP terminal TE2 user belongs (for example, S-CSCF); SCN3 is a session layer control node having media control capability in the network, In the embodiment, it is an MRFC. In this case, the GW in this embodiment, that is, the media gateway under the control of the SCN3, may be an MRFP, and is responsible for implementing media stream forwarding, including codec conversion and the like. In actual physical deployment, SCN3 may be combined with SCN1 or SCN2, or it may be a separate physical entity. Step 301: The TE1 initiates a session, and sends an initial session suggestion request "Invite" message to the SCN1. The SDP description of the "Invite" message carries the media capability set of TE1 itself as the media capability Offerl (original calling terminal capability set). To make it easier to understand, assume that the media capabilities in Offerl are 1, 2, 3, and their priorities are high to low, followed by 3, 2, L. Thereafter, in step 302: SCN1 does not control any gateway, established through the initial session. The "Invite" message is requested, and the call is forwarded to SCN3, where the media Offerl does not change. Next, proceed to step 303: SCN3 controls the media gateway to enable the media gateway to provide new capabilities (assuming media capabilities 4 and 5, and media capability 4 can be converted to and from media capabilities 1 or 3, media capability 5 and media capabilities) 1 or 3 mutual conversion) is added to Offerl and becomes Offer2 (adding the calling terminal media capability set after the new capability provided by the media gateway, ie, media capabilities 1, 2, 3, 4 and 5), SCN3 will simultaneously match The media capabilities of the aforementioned conditions 1 and 2 are added to the SDP description.

I can see that, in this step, the SCN3 adds the parameter of the media capability additionally provided by the media gateway of the node to the media capacity of the calling terminal carried by the message, and records the newly added media capability and the original calling terminal. Media capability set and its priority. It should be pointed out that the newly added media capability is the original media capability set, which is not available in Offerl, but can be converted with the original media capability centralized media capability through the gateway. And, the priority of newly added media capabilities

The level is lower than the priority of each media capability in Offerl. For example, in the present embodiment, media capabilities 4 and 5 have lower priority than media capabilities 1, 2, and 3, assuming that media capability 4 has a higher priority than media capability 5. In step 304: SCN3 establishes a request "Invite" message through the initial session, which will be converted Offei'2 after SDP is sent to SCN2. Step 305: The SCN2 also does not control the media gateway. The initial session establishment request "Invite" message is forwarded to the TE2, where the media Offer2 does not change. In step 306: TE2 finds the intersection (media capabilities 4 and 5) according to the capabilities supported by Offer2 and the terminal (assumed to be media capabilities 4 and 5), and feeds Answer2 to SCN2 according to the priority provided by Offer2 (called terminal Media ability set). Considering that the media capability 4 in Offer2 has a higher priority than the media capability 5, in Answer2, the physical capability 4 is the highest priority media capability. Thereafter, at step 307, SCN2 transparently transmits Answer2 to SCN3. After SCN3 obtains Answer2, it is judged whether the highest priority capability in Answer2 (hereinafter referred to as "first media capability") is provided by the gateway controlled by the node, and if so, the highest priority is selected in the recorded Offerl media capability set. The highest priority media capability in the response message returned to TE1 can be set to the second media capability by the second media capability that the WG converts to the first media capability. The media capabilities of the called terminal media capabilities brought by the response message are deleted or placed at a lower priority than the media capabilities of the second media capability. In this embodiment, the media capability of the highest priority in Answer2 is the media capability 4, which is provided by the WG, so the media capability that can be converted into the media capability 4 is selected in the recorded media capability set of Offerl. That is, media capability 2 and media capability 3, and since the priority of media capability 3 is higher than the priority of media capability 2 in Offerl, media capability 3 is set to the highest priority media capability in Answerl. Thereafter, steps 308 and 309 are performed. If it is determined that the first media capability with the highest priority of the media capability set of Answer2 should not be provided by the gateway of the local node, the called terminal media capability set is transparently transmitted, or the called terminal media is at least partially according to the record. The capability set should be passed down by the media capabilities provided by the node. In step 308, the SCN3 requests the GW to reserve resources for implementing conversion between the media corresponding to the first and second media capabilities. It should be pointed out that the request for reservation is two assets. Source. One is the resource allocated according to the highest priority capability of 0ffer2 interworking with the called party; the other is the resource allocated according to the highest priority capability in Offerl interworking with the calling party. These two resources belong to the same context in the gateway. Thereafter, at step 309, the GW feedback is successfully executed. It should be noted that this does not mean that resources can be used at this time. SCN3 can control the gateway resources to be in the Mute state. In step 310: SCN3 feeds Answerl (the capability set provided by the media gateway) to SCN1 according to the information in Offerl provided by TE1 and the same priority. If TE2 has a capability set that coincides with TE1, it is transparently transmitted according to the capability set of TE2 feedback. Step 311 to step 319: Continue to complete the negotiation process of the calling and called capabilities. Step 320 to step 329: Complete the update of the called and called media. Step 330 to step 341: The called ringing, off-hook, and call-on. When the media stream of the session is established, the media gateway forwards the media corresponding to the second media capability to the media corresponding to the first media capability, and the media corresponding to the first media capability in the backward direction Convert to the media corresponding to the second media capability. As shown in FIG. 3, in steps 306, 307, 310, and 311, the response message is a "183 Session Progress" message, and in other embodiments of the present invention, the response message may also be "180 Ringing." In general, compared with the prior art, in a packet bearer-based session network, when the capability set of the session terminal does not match, the session establishment method of the present invention can utilize network resources to join the session control node through the network. The set of capabilities provided by the controlled media gateway provides more capability options, and only applies for a resource to the media gateway. Under the condition that the session can be successfully established to the maximum extent, the Offer/Answer negotiation efficiency is improved, and the session establishment is ensured. More efficient. The session control node of the embodiment of the present invention includes a media capability adding unit, a priority setting unit, a first media capability determining unit, a second media capability setting unit, a media capability processing unit, a called terminal media capability set delivery unit, and a gateway pre- Leave the resource request unit. among them, a media capability adding unit, configured to add the media capability additionally provided by the gateway controlled by the node to the mediation capability of the calling terminal carried by the message of the forward delivery request establishment session; the additionally provided media capability is the original calling The terminal media capability is not concentrated but can be converted by the gateway and the media capabilities of the original calling terminal media capabilities. a priority setting unit, configured to set a priority of the additionally provided media capability when the media capability adding unit adds the media capability additionally provided by the gateway controlled by the node to the mediation capability of the calling terminal media carried by the message The level is lower than the priority of each media capability of the original calling terminal media capability in the message. The first media capability determining unit is configured to determine whether the first media capability with the highest mediation priority of the called terminal media capability carried by the response message sent by the forward end of the node should be provided by the gateway controlled by the local node. a second media capability setting unit, configured to: when the first media capability determining unit determines to be YES, select the highest priority from the foregoing original calling terminal media capability set, and convert the first media capability through the gateway The second media capability sets the highest priority media capability in the aforementioned response message to the second media capability. a media capability processing unit, configured to: when the first media capability determining unit determines that the first media capability with the highest priority of the called terminal media capability set carried by the response message is to be provided by the gateway controlled by the local node, the response message is sent The media capabilities of the called terminal media that are carried in the media other than the second media capability are deleted or placed at a lower priority. a gateway reservation resource requesting unit, configured to: when the first media capability determining unit determines that the first media capability with the highest priority of the called terminal media capability set carried by the response message is to be provided by the gateway controlled by the local node, to the gateway The requesting the reserved resource is used to implement the conversion between the media corresponding to the first and second media capabilities. The called terminal media capability set delivery unit is configured to: when the first media capability determining unit determines that the first media capability with the highest priority of the called terminal media capability concentration carried by the response message is not provided by the gateway controlled by the local node Transmitting the called terminal media capability set, or at least partially deleting the media of the called terminal media capability set by the local node Pass after the ability. The session control node may be a media resource function controller, and the gateway controlled by the media resource function processor may be a media resource function processor. The session control node may be set in a server to which the terminal user belongs, or may be a separate entity. It should be noted that each unit of the session control node may be independent of each other, and may be integrated and combined in various manners, and details are not described herein.

Although the present invention has been illustrated and described with reference to the preferred embodiments of the present invention, those skilled in the art The spirit and scope of the invention.

Claims

Rights request

A method for establishing a session, comprising: a session control node having a media control capability, when forwardly transmitting a message requesting to establish a session, adding a media capability additionally provided by a gateway controlled by the node to the message The calling terminal media capability is centralized, and the additionally provided media capability is that the original calling terminal media capability is not concentrated but can be converted by the media capability of the original calling terminal media capability by the gateway; the session control node When the response message carrying the called terminal media capability set of the message for establishing the session is forwarded, if it is determined that the first media capability with the highest media priority of the called terminal carried by the response message is determined by the local node Provided by the controlled gateway, the second media capability with the highest priority and capable of being mutually converted by the gateway and the first media capability is selected in the foregoing original calling terminal media capability, and the highest priority media capability in the response message is selected. Set to the second media capability.

The method for establishing a session according to claim 1, wherein the session control node further includes, when the media capability provided by the gateway controlled by the node is added to the media capacity of the calling terminal carried by the message, The priority of setting the additionally provided media capability is lower than the priority of each media capability of the original calling terminal media capability set in the message.

The method for establishing a session according to claim 1, wherein the session control node determines that the first media capability with the highest priority of the media content concentration of the called terminal carried by the response message is to be provided by the gateway controlled by the local node. And the method further includes: deleting or placing the media capability of the called terminal media capability carried in the response message other than the second media capability to a lower priority.

The method for establishing a session according to claim 1, wherein the session control node forwards a response message carrying the media capability set of the called terminal to the request to establish a session, if the Concentrated media capacity of the called terminal carried in the response message The first media capability with the highest priority should not be provided by the gateway controlled by the node, and further includes: transparently transmitting the set of media capabilities of the called terminal, or at least partially deleting the media capabilities of the called terminal to be provided by the node. After the media ability is passed.

The method for establishing a session according to claim 1, wherein the session control node determines that the first media capability with the highest priority of the media content of the called terminal carried by the response message is provided by the gateway controlled by the node. And the method further includes: requesting, by the gateway, a resource to be used for implementing conversion between media corresponding to the first and second media capabilities.

The method for establishing a session according to claim 1, wherein, when the media stream of the session is established, the gateway forwards the media corresponding to the second media capability to the first media capability. The media is backward to convert the media corresponding to the first media capability to the media corresponding to the second media capability.

The session establishing method according to claim 1, wherein, when the session is established, the calling terminal user passes through one or more media control capable sessions in a route to the called terminal user. Control node.

The session establishing method according to any one of claims 1 to 7, wherein the message requesting to establish a session and a response message thereof are a session initiation protocol message; a message for establishing a session in the request and a response thereof The message description protocol describes the media capability set of the calling and called terminals respectively.

9. The session establishing method according to claim 8, wherein the message requesting the establishment of the session is an "Invite" message; and the response message is a "180 Ringing" or "183 Session Progress" message.

10. The session establishing method according to claim 8, wherein the session control node having media control capability is a media resource function controller; and the gateway is a media resource function processor.

A session control node, comprising: a media capability adding unit, configured to add the media capability additionally provided by the gateway controlled by the node to the mediation capability of the calling terminal carried by the message of the forward delivery request establishment session; the additionally provided media capability is the original calling The terminal media capability is not integrated but can be mutually converted by the media capability of the mediation of the mediation of the original calling terminal; the first media capability determining unit is configured to determine the called terminal carried by the response message transmitted by the node in the backward direction. Whether the first media capability with the highest priority of the media capability set should be provided by the gateway controlled by the local node; the second media capability setting unit, configured to: when the first media capability determining unit determines to be YES, from the foregoing original calling terminal media The capability selects the second media capability with the highest priority and can be converted by the gateway and the first media capability, and sets the highest priority media capability in the foregoing response message as the second media capability.

The session control node according to claim 11, further comprising: a priority setting unit, configured to add, by the media capability adding unit, the media capability additionally provided by the gateway controlled by the node to the message When the carrying capacity of the calling terminal is concentrated, the priority of setting the additionally provided media capability is lower than the priority of each media capability of the original calling terminal media capability set in the message.

The session control node according to claim 11, further comprising: a media capability processing unit, configured to: after the first media capability determining unit determines that the called terminal media capability set carried by the response message is prioritized When the highest-level first media capability is to be provided by the gateway controlled by the local node, the media capability of the called terminal carried by the response message is deleted or placed at a lower priority than the media capability of the second media capability.

The session control node according to claim 11, further comprising: a called terminal media capability set delivery unit, configured to determine, at the first media capability determining unit, the called terminal carried by the response message When the first media capability with the highest priority of media capability aggregation should not be provided by the gateway controlled by the node, transparently transmitting the set of media capabilities of the called terminal, or at least partially deleting the media capability set of the called terminal should be provided by the node. After the various media capabilities are passed.

The session control node according to claim 11, further comprising: a gateway reservation resource requesting unit, configured to determine, at the first media capability determining unit, the called terminal media capability carried by the response message When the first media capability with the highest priority is to be provided by the gateway controlled by the local node, the gateway requests the reserved resource to implement the conversion between the media corresponding to the first and second media capabilities.

The session control node according to any one of claims 11 to 15, wherein the session control node is a media resource function controller.

The session control node according to any one of claims 11 to 15, characterized in that the session control node is set in a server to which the terminal user belongs.