WO2008003214A1

WO2008003214A1 - Method, device and system for media flow traversing nat

Info

Publication number: WO2008003214A1
Application number: PCT/CN2007/001643
Authority: WO
Inventors: Xiaoqiang Ding; Haiyan Jian; Qingfeng Meng; Wei Su; Ci Liu; Kai Wen; Fuqing Huang; Lili Xue
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-06-30
Filing date: 2007-05-21
Publication date: 2008-01-10
Also published as: CN101043475A; CN100596125C

Abstract

A method for media flow traversing NAT is provided to solve the problem that the BGF cannot correctly forward media flow in the network because of the overlap of different user addresses. In the method, a first network entity obtains the address information of the media flow and the identifier of the user network, then sends said address information and identifier to the BGF, which will then build the media mapping relation for media flow forwarding based on the address information, and bind said identifier in the mapping relation. The corresponding device and system are also given in the invention.

Description

Method, device and system for media stream traversing network address translation

Technical field

The present invention relates to a network address translation technology in the field of communications, and in particular, to a method, device and system for media stream traversing network address translation. Background technique

IMS is a subsystem of the third generation mobile communication partner organization that supports IP multimedia services. IMS uses SIP call control mechanisms to create, manage, and terminate various types of multimedia services. This kind of multimedia communication is not only simple video and audio communication, but also includes instant messaging, co-location browsing, collaborative work, streaming media, etc., especially the new communication method and traditional voice convergence service. It can be said that IMS provides service integration. basis.

An important feature of IMS is its wide adaptability to various access technologies. At present, the IMS proposed by 3GPP can support 2G and 3G mobile access methods. Due to the independence of IMS and access technologies, standardization organizations such as 3GPP and ITU-T are studying the ability to extend IMS to adapt to fixed terminal in call flow and Compared with the mobile terminal, the authentication capability enhances the access security and QoS capabilities, supports multiple access technologies including fixed networks, and constructs a public core network with fixed network and mobile network convergence.

Due to the lack of the current public network address, a large number of users currently using the network use private network addresses. In order to expand the application range of the IMS network, it is necessary to solve the problem of network address translation NAT. Currently widely used NAT conversion technologies include the following:

1, NAT / ALG mode

A normal NAT device only processes IP headers and TCP/UDP headers, and does not process the carried data. The NAT/ALG mode needs to process the IP address information in the message payload, as shown in Figure 1. An obvious disadvantage of the NAT/ALG method is that the encrypted message content cannot be identified. Therefore, the message must be transmitted in plain text. This makes the message have a great security risk when it is transmitted on the public network.

2, MIDCOM mode

As shown in Figure 2, unlike NAT/ALG, MIDCOM's framework is a mechanism for controlling Middlebox (NAT/FW) with a trusted third party (MIDCOM Agent). The intelligence of business identification is also transferred from Middlebox to the external MIDCOM Agent, so the application protocol is transparent to Middlebo.

3, STUN way

The private network access user obtains the external address whose address corresponds to the egress NAT through some mechanism, and then fills in the external address on the egress NAT directly in the address information described in the packet payload, instead of the user in the private network. The private IP address, so that the content of the packet payload does not need to be modified when passing through the NAT. The IP address of the packet header can be translated according to the normal NAT process. The IP address information and the header address information in the payload are consistent. of.

In the current network, a large number of private network users need to use the services provided by the IMS system. The current solution includes signaling network address translation traversal and media network address translation traversing two parts. The basic networking is shown in Figure 3.

For signaling traversal NAT, the BFD function (PED) is simply used as a NAT device. When a private network user registers, the BGF solidifies the signaling channel assigned to the user. It is used for subsequent signaling interaction between the end user and the IMS system. The main processing flow is shown in Figure 4:

Step 400: The private network user UE1 initiates registration of the REGISTER message, and the message reaches the BGF through the private network.

Step 401: The BGF receives the REGISTER message, determines that the message needs to be sent to the P-CSCF on the public network through the destination address, establishes a temporary mapping channel (assigns the network side address and port), and transmits the message to the P-CSCF.

Step 402: The P-CSCF determines that the user to be registered is a private network user, and the BGF is temporarily assigned to the signaling channel (network side address and port) of the user through the interface between the P-CSCF and the BGF, and is sent to the BGF. The BGF is required to cure the signaling channel of the user for subsequent signaling interaction between the private network user and the P-CSCF.

Step 403: After completing the signaling channel curing process, the BGF sends the processing result to the P-CSCF through the interface between the P-CSCF and the BGF.

Step 404: After receiving the BGF response, the P-CSCF completes the subsequent registration request processing, and The REGISTER message is forwarded; the traversal of the signaling NAT has been completed.

For the media to traverse the NAT, the P-CSCF is required to send the media stream information in the session signaling to the BGF for establishing the media mapping channel in the session. The INVITE message in the IMS system is taken as an example. Show:

Step 500: The private network user UE1 initiates a session establishment request INVITE, and the message reaches the BGF through the private network.

Step 501: The BGF forwards the INVITE message to the P-CSCF through the signaling channel that is solidified when the user registers.

Step 502: After receiving the INVITE message, the P-CSCF sends the media stream address and port information used by the UE1 user session to the BGF, and requests the BGF to establish a media channel when the user session is established (the access side address, port, and port allocated by the BGF) Network side address and port).

Step 503: After receiving the media mapping establishment request, the BGF allocates a media mapping channel according to the media stream address and port information of the UE1 (the access side address, port, and network side address and port of each media stream corresponding to the BGF). The processing response is brought to the P-CSCF.

Step 504: After receiving the media mapping establishment success response, the P-CSCF replaces the media stream address and port information of the SDP message body in the INVITE request with the network side address and port allocated by the BGF, and then forwards the INVITE message. At this point, the initial creation of the user media mapping on the calling side is completed.

The above scenario may cause problems in some scenarios. The following takes the basic scenario of a VLAN user as an example, as shown in Figure 6.

Users UE1 and UE2 belong to different VLANs. The two users have overlapping addresses. Different VLANs 1 and 2 are connected to the public network through different physical interfaces of the BGF. Different VLAN users have no problem with signaling NAT traversal. This is because the network ports that different VLAN users access through the BGF are different. The BGF can allocate different network side addresses or ports. When the signaling channel is cured, the BGF can be based on Different network side addresses and ports cure it for subsequent signaling interactions between the user and the network.

For media network address translation traversal, because the addresses of different users overlap, according to the foregoing scheme, the media mapping data of different VLAN users sent by the P-CSCF to the BGF will be the same, then When a media map is assigned, the BGF will not know which VLAN mapping pair is assigned. If the BGF does not have a VLAN to determine the media mapping pair, although the two VLAN user media channels can be distinguished by different address group identifiers, in the session, the uplink media stream that arrives at the BGF (from the UE side to the network side) cannot Determine which channel to use to forward the media stream. For other networks, the same problem exists when the addresses of different users overlap. Summary of the invention

The embodiment of the invention provides a method, a device and a system for media stream traversing network address translation, so as to solve the problem that the media mapping relationship established in the prior art cannot correctly forward the media stream when different user addresses overlap.

A method for establishing a media mapping relationship for converting a media stream includes the following steps: a first network entity acquires address information of a media stream to be transmitted and an identifier capable of identifying a network where the user is located, and sends the address information and the identifier To the border gateway function BGF entity;

The BGF entity establishes a media mapping relationship for forwarding the media stream according to the address information, and binds the identifier in the mapping relationship.

A method for establishing a media mapping relationship for converting a media stream includes the following steps: The first network entity acquires related information of the media stream that needs to be transmitted and sends the information to the second network entity responsible for the QoS policy decision, where the related information includes Address information and quality of service QoS information; the second network entity generates a corresponding QoS policy according to the QoS information, and sends the QoS policy and the address information to the BGF entity;

The BGF entity establishes a media mapping relationship for forwarding the media stream according to the address information, and associates the QoS policy with the media mapping relationship.

A method for media stream traversing network address translation includes the following steps:

Border gateway function in the network The BGF entity receives the media stream sent by the user;

The BGF entity determines, according to the identifier that can identify the network where the user is located, and the source address information in the media stream, to match the media mapping relationship, where the end of the media stream is forwarded, where the media mapping relationship is bound to identify the user. Identification of the network; The BGF forwards the media stream through the determined port.

A network device, including:

Means for obtaining address information of a media stream to be transmitted and an identifier capable of identifying a network in which the user is located;

And a device for sending a message for establishing a media mapping relationship, where the message includes the identifier that can identify a network where the user is located.

A network device, including:

And means for establishing a media mapping relationship for forwarding the media stream, and binding the identifier in the media mapping relationship, for the address information of the media stream that is transmitted according to the requirement and the identifier of the network where the user is located;

When receiving the media stream sent by the user equipment, the device that matches the media mapping relationship according to the identifier and source address information of the network where the user is located to determine a port for forwarding the media stream, and forwards the media stream through the port .

A network system, including:

a first network entity, configured to acquire address information of a media stream that the user equipment needs to transmit, and an identifier that can identify the network where the user is located, and send a BGF entity that is used to forward the media mapping relationship of the media stream. Establishing a media mapping relationship for forwarding the media stream according to the address information and the identifier provided by the network control entity, and binding the identifier, and when receiving the media stream sent by the user equipment, according to the network capable of identifying the user The identification and source address information matches the media mapping relationship to determine a port for forwarding the media stream, and the media stream is forwarded through the port.

A network system, including:

a first network entity, configured to acquire related information of a media stream that needs to be transmitted, and send the related information, where the related information includes address information and quality of service QoS information;

a second network entity, configured to generate a corresponding QoS policy according to the QoS information sent by the first network entity, and send the QoS policy and the address information; The BGF entity is configured to establish, according to the address information, a media mapping relationship for forwarding the media stream, and implement the QoS policy.

The embodiment of the present invention binds the network identifier of the network where the user is located when the boundary media gateway function entity establishes the media mapping relationship for forwarding the media stream, and queries the media mapping relationship by using the source address and the network identifier when forwarding the media stream sent by the user side. The port for forwarding the media stream is obtained. Therefore, even if the addresses of the users in different networks overlap, the border media gateway function entity can correctly match the media mapping relationship of the forwarding media stream.

The embodiment of the present invention generates a corresponding QoS policy according to the QoS information of the media to be transmitted and associates with the established media mapping relationship, and uses the QoS policy to perform QoS control on the media stream forwarded by the media mapping relationship, thereby fully ensuring the transmission media. The service quality requirements of the flow; at the same time, the process of establishing the media mapping relationship is merged with the process of generating the QoS policy, which simplifies the processing flow and improves the system efficiency. DRAWINGS

1 is a schematic structural diagram of a data packet in the prior art;

1 is a schematic structural diagram of a frame of a MIDCOM in the prior art;

3 is a schematic diagram of a network structure in which a user uses an IMS service through a NAT in the prior art; FIG. 4 is a flowchart of implementing signaling traversal NAT in the prior art;

FIG. 5 is a flow chart of establishing a media mapping channel by using a session request INVITE in an existing IMS network;

6 is a schematic diagram of a network structure of a VLAN user using an IMS service in the prior art; FIG. 7A is a schematic structural diagram of a system for binding a VLAN in a media mapping relationship in a BGF according to an embodiment of the present invention;

7B is a flowchart of establishing a user identifier and a VLAN identifier binding by using a registration process according to an embodiment of the present invention;

FIG. 8 is a flowchart of establishing a media mapping relationship when a user establishes a session according to an embodiment of the present invention; FIG. 9 is a system diagram of supporting media mapping relationship establishment and service quality control according to an embodiment of the present invention; Intention

FIG. 10 is a flowchart of establishing a media mapping and delivering a service quality control policy according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a system of a multi-level NAT scenario according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of a system for dynamically acquiring VLAN information by a BGF according to an embodiment of the present invention. detailed description

In order to solve the problem of the media stream transmission caused by the overlapping of different user addresses, the embodiment binds the identifier of the network where the user is located when establishing the media stream mapping relationship for forwarding the media stream. Further, when the media stream is forwarded, the source address in the media stream and the identifier of the network in which the user is located are matched with the media stream mapping relationship to determine a port for forwarding the media.

In this embodiment, the IMS service of the virtual local area network (VLAN) is used as an example for detailed description. The identifier of the network where the user is located adopts the VLAN identifier.

As shown in Figure 7A, users in different VLANs access the BGF (or Policy Enforcement Function, PEF) through different physical ports. The BGF acts as a network address translation NAT device. When the VALN user registers, the BGF solidifies the signaling channel assigned to the user for subsequent signaling interaction between the end user and the IMS system.

In this embodiment, the interface between the P-CSCF and the BGF is widely deployed, and the binding relationship between the user and the VLAN identity of the VLAN network is established when the user registers, and the BGF identifies the VLAN and establishes the session in the subsequent session establishment process. Media mapping relationship binding. Because different VLAN users access the BGF through different physical interfaces, the BGF can distinguish the user's VLAN ID based on the physical interface. When receiving the media stream sent by the VLAN user, the BGF matches the media mapping relationship according to the VLAN identifier and the source address information to determine a port for forwarding the media stream, and forwards the media stream through the port.

Referring to FIG. 7B, when the user registers, the process of establishing the binding relationship between the user and the VLAN ID by the proxy call session control function P-CSCF in the IMS system is as follows:

Step 700: The VLAN user UE1 initiates registration of the REGISTER, and the message reaches the BGF through the VLAN. Step 701: The BGF receives the REGISTER message, because different VLANs access the BGF through different physical interfaces, and the interface information BGF can allocate the IP address and port of the network side to the UE 1 user, establish a temporary signaling channel, and register after completion. The REGISTER request is passed to the P-CSCF.

Step 702: The P-CSCF determines that the registered user is a private network user, and the BGF is temporarily assigned to the signaling channel (network side address and port) of the user through the interface between the P-CSCF and the BGF, and is sent to the BGF. The BGF is required to cure the signaling channel of the user for subsequent signaling interaction between the private network user and the P-CSCF.

Step 703: After successfully processing the curing request, the BGF sends the VLAN ID of the VLAN network where the UE1 user is located to the P-CSCF by using a response message.

Step 704: After receiving the BGF response, the P-CSCF saves the association relationship between the user and the VLAN ID, and is used to establish the media NAT when the session is established. After completing the subsequent registration request processing, the P-CSCF forwards the REGISTER message. At this point, VLAN user signaling NAT traversal has been completed.

As shown in Figure 8, when a VLAN user establishes a session, the media mapping relationship is established between the user and the VLAN ID. The process is as follows:

Step 800: The UE1 in the VLAN sends a session establishment request INVITE, and the media stream related information required for the user session is carried by the SDP message body in the INVITE message, and the request reaches the BGF through the VLAN.

Step 801: The BGF forwards the INVITE message to the P-CSCF through the signaling channel that is solidified when the user registers.

Step 802: After receiving the INVITE message, the P-CSCF sends the media related information of the UE1 session to the BGF, and uses the media mapping when the BGF establishes the user session, and the P-CSCF binds the VLAN ID to the user when registering. It is sent to the BGF for BGF to distinguish different VLAN users to establish media mapping.

Step 803: The BGF establishes a media mapping relationship pair in the session according to the media stream information (IP address and port) of the UE1 session and the VLAN ID associated with the UE1, that is, the VLAN ID is bound in the media mapping relationship, and the response message is received. Bring this information to the P-CSCF.

Step 804: The P-CSCF replaces the INVITE request with the network side address and port allocated by the BGF. The media stream address and port of the SDP message body, and then forward the INVITE message to the called side. At this point, the initial creation of the user media mapping on the calling side is completed (the session establishment may be performed multiple times).

Step 805: The UE1 sends a media stream.

Step 806: After receiving the media stream, the BGF extracts the VLAN identifier and the source address information of the user, and matches the media mapping relationship to determine a forwarding port, and the determined port sends the media stream.

When the session needs to be QoS controlled, the scenario is shown in Figure 9. In this scenario, different VLANs are accessed through different physical interfaces of the BGF. The P-CSCF and the BGF use the internal interface (using the COPS protocol) to cure the signaling channel. Because the interface is not standardized, the BGF may implement the signaling proxy function. cancel. The QoS service required by the user is completed through the interaction between P-CSCF, SPDF, and BGF. The interface between P-CSCF and SPDF, and the interface between SPDF and BGF are standard Gq, and la interface.

In this embodiment, the establishment of the media NAT mapping is integrated in the QoS process, that is, by extending the Gq, la interface, supporting media NAT mapping establishment and QoS control. In this scenario, the registration process of the VLAN user is the same as described above. The establishment of the signaling channel is completed by the BGF itself. The curing of the signaling channel is completed by the internal interface between the P-CSCF and the BGF. When the BGF implements the signaling proxy function, the interface can be cancelled. For the session process, the media mapping pair establishing the session in the BGF and the implementation of the QoS policy can be unified. By extending the Gq between the P-CSCF and the SPDF, the interface and the LA interface between the SPDF and the BGF, the QoS is delivered. When controlling policies, media NAT mapping is also handled, which simplifies the process. Referring to Figure 10, the process of establishing a media mapping relationship is as follows:

Step 1000: The UE1 in the VLAN sends a session establishment request INVITE, and the media stream related information required by the user session is carried by the SDP message body in the INVITE message, and the request reaches the BGF through the VLAN.

Step 1001: The BGF forwards the INVITE message to the P-CSCF through the signaling channel that is solidified when the user registers.

Step 1002: The P-CSCF sends the address and port information of the media stream required by the UE1 user session, the QoS information, and the VLAN ID bound by the user registration to the service-based policy decision function SPDF through the extended Gq' interface. Pass to BGF to distinguish different VLAN users to establish media mapping And specify a QoS policy.

Step 1003: After receiving the request, the SPDF calculates a policy decision for the final control of the QoS resource according to the local policy, and sends the policy decision information, the media stream address, the port information, and the VLAN ID of the UE1 user session to the BGF through the extended LA interface. .

Step 1004: The BGF establishes a session-time media mapping channel according to the media stream address, the port information, and the VLAN ID information of the UE1 user session, and implements the QoS policy delivered by the SPDF. After the completion, the processing result is uploaded to the SPDF device through the extended la interface.

Step 1005: After the SPDF completes the subsequent QoS processing, the media mapping information is transparently transmitted to the P-CSCF through the extended Gq 'interface.

Step 1006: The P-CSCF replaces the media stream address and port of the SDP message body in the INVITE request with the network side address and port allocated by the BGF, and then forwards the INVITE message to the called side. At this point, the initial creation of the user media mapping on the calling side is completed.

Step 1007: After the called side returns 183 response, the P-CSCF judges that the previously established media mapping and QoS information needs to be changed, and then the SPDF is notified through the Gq interface. For example, the mapping relationship between the pronunciation frequency stream and the video stream is established first, and only the audio stream is forwarded after negotiation, and then the mapping relationship of the forwarded video stream is notified. For another example, after the negotiated QoS information changes with the previous QoS information, the QoS policy needs to be regenerated and the BGF change is notified.

Step 1008: The SPDF sends the changed QoS policy and media mapping information to the BGF through the extended la interface.

Step 1009: After the BGF finishes changing the media mapping information, it returns a response to the SPDF.

Step 1010: The SPDF transparently transmits the media mapping information to the P-CSCF.

Step 1011: After the P-CSCF changes the media mapping information in the INVITE message body, the P-CSCF forwards the message to the user UE1.

In step 1007, when the P-CSCF determines that the mapping relationship and the QoS information do not need to be changed, step 1008 to step 1012 are not performed.

The above-mentioned media NAT mapping establishment and QoS flow integration are also applicable to other application scenarios that need to complete NAT mapping and QoS control, and are not limited to binding VLANs to prevent different uses. In applications where the address of the user overlaps and the media cannot be forwarded correctly.

The above method is also applicable to the scenario in which multi-level NAT exists as shown in FIG. In this scenario, the establishment of VLAN user signaling and media channels is completely the same as the foregoing scheme. For media NAT, the intermediate cascaded NAT devices 1, 2 only serve as NAT functions, and do not change the media stream address and port of the signaling message body. The message, therefore, the media stream address and port delivered by the P-CSCF to the BGF is still the information of the original UE1, and the BGF establishes a media mapping channel accordingly.

As shown in Figure 12, when different VLANs access the BGF through the same physical interface, the BGF dynamically obtains VLAN information. For example, the IP header of the data packet sent from SWITCH includes a VLAN identifier, which is used to indicate which VLAN network the packet comes from. When the same physical interface of the BGF receives a packet containing a different VLAN identifier, the BGF can establish different NAT mappings to distinguish different VLANs. When a packet on the network side is sent to a different network side address or port of the BGF, the BGF can forward the corresponding VLAN identifier to the IP header and forward it to SWITCH. The SWITCH can correctly distribute the data packet to the user. Therefore, the registration and session flow of the VLAN user described above also applies to the scenario shown in Figure 12.

The identifier for distinguishing the network where the user is located is not limited to the network identifier, but also the network segment information. The network device in this embodiment includes: an acquiring device, configured to acquire address information of a media stream that needs to be transmitted, and an identifier that can identify a network where the user is located; and a sending device, configured to send a message for establishing a media mapping relationship, The message includes the identifier that can identify the network where the user is located.

Another network device in this embodiment includes: a creating device, configured to establish, according to the address information of the media stream that needs to be transmitted, and the identifier of the network where the user is located, a media mapping relationship for forwarding the media stream, and the media mapping relationship Binding the identifier; determining means, configured to: when receiving the media stream sent by the user equipment, match the media mapping relationship according to the identifier and source address information of the network where the user is located to determine a port for forwarding the media stream, and The media stream is forwarded through the port. The above method is also applicable to other media stream processing of different terminals with overlapping addresses, for example, address weight The stack user needs to perform QoS control, or query applications such as the physical location information of the overlapping users. In this embodiment, when the boundary media gateway function entity establishes a media mapping relationship for forwarding the media stream, the network identifier of the network where the user is located is bound, and when the media stream sent by the user side is forwarded, the source address and the network identifier are used to query the media mapping relationship. The port of the media stream is forwarded. Therefore, even if the addresses of users in different networks overlap, the border media gateway function entity can correctly match the media mapping relationship of the forwarding media stream.

In this embodiment, the QoS policy of the media to be transmitted is generated according to the QoS information of the media to be transmitted, and is associated with the established media mapping relationship, and the QoS policy is used to perform QoS control on the media stream forwarded by the media mapping relationship, so that the media stream can be fully guaranteed. At the same time, the process of establishing a media mapping relationship is merged with the process of generating a QoS policy, which simplifies the processing flow and improves system efficiency. The spirit and scope of the invention. Therefore, it is intended that the present invention cover the modifications and variations of the invention as claimed.

Claims

Rights request

A method for establishing a media mapping relationship for converting a media stream, comprising the steps of:

The first network entity acquires address information of the media stream that needs to be transmitted and an identifier that can identify the network where the user is located, and sends the address information and the identifier to the border gateway function BGF entity;

2. The method according to claim 1, wherein the identifier of the network in which the user is located is acquired when the user registers.

The method according to claim 1, wherein the identifier capable of identifying the network where the user is located is network identifier or address segment information.

4. The method according to claim 1, wherein the first network entity further obtains quality of service QoS information of the media stream that needs to be transmitted, and sends the identifier, the address information, and the QoS information to the QoS policy decision. And the second network entity generates a corresponding QoS policy, and sends the identifier, the address information, and the QoS policy to the BGF entity, where the BGF entity implements the QoS policy.

The method according to claim 4, wherein the second network entity transparently transmits the address information and the identifier.

6. The method according to claim 4 or 5, wherein the information about the media stream is transmitted by extending an interface between the first network entity and the second network entity; by extending the second network entity and the BGF entity The interface between the interface transmits the address information, the QoS policy, and the identity.

7. The method according to claim 6, wherein the first network entity is a P-CSCF entity in an IMS network, and the second network entity is an SPDF/PDF entity in an IMS network; the P-CSCF An extended Gq, an interface between the entity and the SPDF/PDF entity, and an extended la interface between the SPDF/PDF entity and the BGF entity.

8. A method for establishing a media mapping relationship for converting a media stream, characterized in that The following steps:

The first network entity acquires related information of the media stream that needs to be transmitted and sends the information to the second network entity responsible for the QoS policy decision, where the related information includes the address information and the quality of service QoS information; the second network entity generates the corresponding information according to the QoS information. a QoS policy, and sending the QoS policy and the address information to the BGF entity;

The BGF entity establishes a media mapping relationship for forwarding the media stream according to the address information, and implements the QoS policy.

The method according to claim 8, wherein the related information further comprises an identifier capable of identifying a network where the user is located, the second network entity sends the identifier to the BGF entity, and the BGF entity establishes the identifier and the identifier Media mapping relationship binding.

10. The method according to claim 9, wherein the first network entity acquires the identifier of the network in which the user is located during the user registration process.

The method according to claim 9, wherein the second network entity transparently transmits the address information and the identifier.

The method according to claim 11, wherein the identifier is network identifier or address segment information.

The method according to any one of claims 8 to 12, wherein the related information of the media stream is transmitted by extending an existing interface between the first network entity and the second network entity; The existing interface between the network entity and the BGF entity transmits the address information, the QoS policy, and the identity.

14. The method according to claim 13, wherein the first network entity is a P-CSCF entity in an IMS network, the second network entity is an SPDF/PDF entity in an IMS network; and the P-CSCF entity and The SPDF/PDF entity is an extended Gq' interface, and the SPDF/PDF entity and the BGF entity are extended la interfaces.

A method for media stream traversing network address translation, comprising the following steps: a border gateway function in a network, a BGF entity receiving a media stream sent by a user;

The BGF entity is capable of identifying the identity of the network in which the user is located and the source in the media stream. The address information is matched with the media mapping relationship, and the end of the media stream is determined, where the media mapping relationship is bound with an identifier that can identify the network where the user is located;

The BGF forwards the media stream through the determined port.

16. The method according to claim 15, wherein the media stream is transmitted to the BGF after being converted by a multi-level network address.

17. The method according to claim 15, wherein the BGF determines the identifier according to a physical port accessed by the user; or the BGF dynamically extracts the identifier from the media stream.

The method according to any one of claims 15 to 17, wherein the identifier is network identifier or address segment information.

19. A network device, comprising:

20. A network device, comprising:

And means for establishing a media mapping relationship for forwarding the media stream, and binding the identifier in the media mapping relationship, by using the address information of the media stream that is transmitted according to the requirement and the identifier of the network in which the user is located;

21. A network system, comprising:

a first network entity, configured to obtain address information of a media stream that the user equipment needs to transmit, and an identifier that can identify the network where the user is located, and send an irir that establishes a media mapping relationship for forwarding the media stream. The border gateway function BGF entity, And establishing a media mapping relationship for forwarding the media stream according to the address information provided by the network control entity and the identifier, and binding the identifier, and receiving When the media stream is sent to the user equipment, the media mapping relationship is matched according to the identifier and source address information of the network where the user is located to determine a port for forwarding the media stream, and the media stream is forwarded through the port.

The network system according to claim 21, further comprising:

The second network entity is configured to complete the QoS policy decision, receive the QoS information obtained by the first network entity, generate a corresponding QoS policy according to the QoS information, and send the QoS policy to the BGF entity, and the BGF entity further implements the QoS policy.

The network system according to claim 21, wherein the first network entity sends the address information, the identifier and the QoS information to the second network entity through the extended interface, and the second network entity uses the extended interface The address information and the identifier are transparently transmitted to the BGF entity.

.

24. The network system according to claim 22, wherein the first network entity is a P-CSCF entity in an IMS network, the second network entity is an SPDF/PDF entity in an IMS network; and the P-CSCF entity Between the SPDF/PDF entity is an extended Gq, interface, and the SPDF/PDF entity and the BGF entity are extended la interfaces.

25. A network system, comprising:

a second network entity, configured to generate a corresponding QoS policy according to the QoS information sent by the first network entity, and send the QoS policy and the address information;

And a BGF entity, configured to establish, according to the address information, a media mapping relationship for forwarding the media stream, and implement the QoS policy.