Heterogeneous mobile radio system

Heterogeneous Mobile Wireless System

Technical field

The present invention relates to a heterogeneous mobile wireless system, which has at least one first and one second mobile wireless network, wherein each of the two mobile wireless networks includes an access node for a packet data network.

Background technique

Public mobile wireless networks, especially 2G/3G networks, are set up in such a way that they provide services in the widest possible area of a country. It may happen here that in a certain area (that is, in a certain cell), especially under the high user density in the area or the cell, the capacity for the required service is insufficient. In addition, this problem has become more prominent when the mobile access system to the Internet, such as packet data service GPRS (General Packet Radio Service), is used in mobile wireless networks in accordance with the GSM standard or UMTS (Universal Mobile Telecommunications). The system) performs new services or services with high bandwidth, such as multimedia.

This problem prominently occurs in places and buildings such as airports or fairs, where the problem can also come from the user's lower movement speed. Here, the above-mentioned problem can be solved by, for example, two measures described below.

It can be considered to install the smallest cell, that is, a micro cell or a pico cell, with the same technology as the entire network, for example, a combination of overlapping cells and umbrella cells. According to this measure, users will not be disturbed, that is, they will not feel the additional cells installed in the entire network, that is, the installation is completely transparent to the users of the mobile wireless network. In addition, the installation of such a minimum cell is seamlessly introduced to the network operator of the mobile wireless network with its operating concept. There is no transmission loss or undesired interruption in transmission. In addition, no special measures are usually required to charge and/or authenticate the corresponding users of the mobile wireless network. However, it is extremely expensive to install such a smallest cell in the entire system. What is involved is extremely expensive wireless technology because it supports very high mobility. In addition, the network may be overburdened by signal traffic due to excessive handoffs between cells due to small cells. Here may touch on the wireless technology, especially the boundary of the transmission frequency.

In addition, you can consider installing another seamless access system to the Internet. This may be, for example, a wireless LAN (Local Area Network), Bluetooth, or similar system. The advantage here is that the actual additional transmission capacity is achieved. In addition, this alternative system is generally not as expensive as the installation of the smallest cell mentioned. However, the disadvantage lies in the fact that it is impossible or only limited to seamlessly transition from a 2G/3G mobile wireless network to the other mobile wireless network. This means that losses and interruptions may occur in transmission. For example, when the WLAN (Wireless LAN) belongs to another network operator who is not a 2G/3G mobile wireless network, the user must perform a second authentication on the WLAN, that is, the installation of the other mobile wireless network is not transparent to the user. Conversely, if the WLAN is operated by the same network operator as the 2G/3G mobile wireless network, in order to operate it, at least new methods for authentication and charging must be introduced, which increases the operating cost of the system.

So far, the solution is usually selected at the IP layer in order to realize a heterogeneous mobile wireless system, such as combining a 2G/3G mobile wireless network with a WLAN that implements IP exchange. Here, the IP layer refers to a protocol of the Internet Protocol (IP) family, which is independent of transmission technology (such as LAN or WAN) and access technology (mobile wireless network, fixed network). One of the most frequently discussed solutions is mobile IP corresponding to, for example, RFC 2002 for IP-v4. In 3GPP In 2G/3G networks, Internet access is mostly implemented in accordance with 3GPPTS23.060. Among them, an access node (GGSN: Gateway GPRS Support Node) is provided, and these nodes respectively implement access to the Internet and support the corresponding Internet Protocol (IP). Among them, a fixed reference point is set for the Internet on the GGSN, and each user can access the Internet through an IP address. In the core network, that is, in the actual mobile wireless network, the mobility between the access node (GGSN) and the existing network service node (serving GPRS support node: SGSN) is realized through the GTP tunnel. All connections between the mobile terminal (MT) and up to the access node GGSN along with the control data describing the connection are called packet data protocol (PDP) contexts. The user can be accessed by the corresponding user through a fixed IP address provided by, for example, an Internet service provider (ISP). If the user enters a 2G/3G network, he gets a preferred dynamic IP address from the Internet service provider. Among them, the Internet service provider can be the same organization as the mobile wireless network operator of the 2G/3G network. In order to realize the user's conversion between 2G/3G network and WLAN with the help of mobile IP, the following measures must be taken: the user must pass the IP address of its 2G/3G mobile wireless network through the home agent (Home Agent) Register in the Internet. The home agent (HA) can be provided by a second (local) ISP. The user can be accessed through a fixed IP address or another identification in the network of the second ISP on the HA. Then, the data packet from the home agent is transmitted to the access node GGSN of the IP address in the 2G/3G mobile wireless network through a mobile IP (MIP) tunnel. In order for the packet to reach the users mobile terminal (MT), there must be a foreign agent (Foreign Agent, FA), which decapsulates the packet sent to the GGSN and delivers it to a mobile terminal belonging to a fixed home address. If the user enters the WLAN, and there is also a foreign agent (FA) in a WLAN controller that functions as an Internet access node, the home agent in the Internet can also directly control the WLAN with the help of mobile IP (MIP) The device transfers the packet. The advantage of this solution is that users can maintain their IP addresses when switching systems, so that many applications do not have to be interrupted. But the disadvantage is that, as explained at the beginning, new methods or measures for access permission control and charging must be introduced or adopted in the WLAN range. If you want to switch between two mobile wireless networks or two access systems (as described here between the 2G/3G mobile wireless network and WLAN), as a service provided by the network operator of the 2G/3G mobile wireless network, Then it must also provide a home agent and provide its users with a home IP address, because the home agent controls and routes how packets arrive at the MT. In addition, the identification of each network user and the charging data should be correlated with each other. This causes operating overhead. In addition, due to the agreement, it may cause a longer conversion time, because the registration data and authentication data must be exchanged between the MT, FA and services for authentication, authorization and charging (AAA) and HA. The long distance between the home agent and the local network where the mobile user is located can also cause a larger conversion time.

Summary of the invention

The technical problem to be solved by the present invention is to provide a mobile wireless system, which has at least the advantages of the two measures and overcomes the disadvantages at the same time.

The above-mentioned technical problem is solved by the mobile wireless network of the present invention according to claim 1. Other preferred embodiments are described in the dependent claims.

According to claim 1, a heterogeneous mobile wireless system is provided for providing mobile terminals (MT) with services from a packet data network, the system having at least a first mobile wireless network and a second mobile wireless network, wherein The mobile wireless network includes at least one access node to the packet data network, and the access node of the second mobile wireless network can only indirectly pass through the access node and the packet data network of the first mobile wireless network. Internet connection.

In a preferred embodiment of the heterogeneous mobile wireless system, the packet data network is the public Internet.

According to the present invention, at least one first mobile wireless network and one second mobile wireless network are combined, wherein the two mobile wireless networks are respectively connected to a packet data network (preferably to the Internet) through at least one access node. In the case that the first mobile wireless network is a 2G/3G mobile wireless network, the access node will be implemented through a GGSN (Gateway GPRS Support Node). In a second mobile wireless network such as a WLAN, an access node with functions according to the present invention is called a Local Mobility Agent (LMA). The access node becomes an interface to a packet data network (preferably to a fixed IP network) through the IP routing function and serves as an access router, that is, its terminieren protocol for mobile wireless technology and access technology. Among them, the IP protocol, especially the mobile IP (MIP) protocol can also be preferably applied. According to the present invention, the access node of the second mobile wireless network is not directly connected to the packet data network (preferably the Internet), but all data is connected to it through the access node of the first mobile wireless network.

In addition, at least one proxy function can be integrated in the access node of the first mobile wireless network. In a preferred embodiment of the mobile wireless system of the present invention, it is a home agent function, preferably a routing function. As a result, the routing function of the packet data network (preferably the Internet) is in the first mobile wireless network, preferably in the 2G/3G mobile wireless network. In this way, the operation of the home agent in the packet data network or the Internet, and the allocation of fixed IP addresses in the Internet are omitted. The IP address in the mobile wireless system can remain unchanged during conversion between the first and second mobile wireless networks. In this way, there will be no interruption of the application. The routing is significantly improved.

In a preferred embodiment of the heterogeneous mobile wireless system according to the present invention, the first mobile wireless network constitutes an overlay network (OverlayNetz) of the second mobile wireless network. Wherein, the power supply within the power supply range (Versorgungsgebieten) of the second mobile wireless network is also guaranteed by the first mobile wireless network. The first mobile wireless network is particularly preferably a 2G/3G mobile wireless network. Among them, under the condition of using the second mobile wireless network, the connection between the first mobile wireless network and the mobile terminal is not abandoned, that is, the mobile terminal is "always connected" in the first mobile wireless network. Therefore, it can be proved by the overlapping network that one or more functions of the first mobile wireless network can also be used for the second mobile wireless network. In this way, according to a preferred manner, the first mobile wireless network (preferably 2G/3G mobile wireless network) can authenticate the mobile wireless network users and receive the first mobile wireless network (preferably 2G/3G mobile wireless network). The cost is for the second mobile wireless network (preferably WLAN). It has the advantage that it is not necessary to authenticate a mobile wireless network user multiple times, that is, even if the user wishes to use two mobile wireless networks, he does not need to be re-authenticated again when switching between the two mobile wireless networks. Thus, all users who can log in to the first mobile wireless network (preferably 2G/3G mobile wireless network) can also use the services of the second mobile wireless network (preferably WLAN). Here, it may also be a roaming user of another mobile wireless network who can access the first mobile wireless network. In addition, inexpensive technologies, especially Internet technologies, can be used for the second mobile wireless network (preferably WLAN), because these technologies do not have to have authentication functions and charging functions. For the operators of mobile wireless networks, there will be no or only few changes in operation and operating concepts. The second mobile wireless network (preferably WLAN) can be added to the entire system seamlessly, that is, without interruption and loss. Because all services of the second mobile wireless network are also transmitted through the first mobile wireless network, there is enough information in the first mobile wireless network so that charging can be extremely flexible. In this way, for example, the amount of data transmitted in the second mobile wireless network (preferably WLAN) can be charged to be equal to the amount of data transmitted in the first mobile wireless network (preferably 2G/3G mobile wireless network). However, it is also possible to charge no charge or charge according to the standards of the Internet service provider. Therefore, in the latter case, it is possible to satisfy any appropriate condition or business situation. can

In another preferred embodiment of the heterogeneous mobile wireless system, when using the home agent function, especially the mobile IP home agent function, the dedicated data can be selectively transmitted only through the second mobile wireless network.

When using the GTP protocol, the data path between the access node of the second mobile wireless network and the access node of the first mobile wireless network can be realized through the generalization of the existing "secondary PDP context" concept of GPRS, where , The use of the packet distribution function for the secondary PDP context, so as to also distribute the data traffic between the first mobile wireless network and the second mobile wireless network, and among them, the tunnel from the GGSN can have different target addresses .

In addition, when using the mobile IP home agent function in the access node of the first mobile wireless network, it not only transfers all services between the first mobile wireless network and the second mobile wireless network, but also corresponds to The service class that may be set only transmits a specific data group through the second mobile wireless network. This corresponds to an extension of MIP.

In addition, it may be preferable to extend the mobile IP registration for the signal transmission formed by the connection between the access node of the first mobile wireless network and the second mobile wireless network, that is, to extend the session-specific data on the PDP context of the first mobile wireless network. For example, about user and context identification, and about the session-specific data formed by the tunnel formed between the access node of the second mobile wireless network and the first mobile wireless network, such as (as in the TFT of GPRS) for service classification Data flow characteristics. In this way, the second mobile wireless network can be used for, for example, Voice over IP (Voice over IP) or multimedia connections, and the first mobile wireless network can be used for other data services.

Preferably, the first access node adopts the coupling with the PDP context of the second mobile wireless network having the context in the first mobile wireless network. In addition, only if at least one context is established in the first mobile wireless network, the first access node preferably allows the context in the second mobile wireless network.

Preferably, there is a control function in the access node of the second mobile wireless network, and the function of this function is to enable the data packets to be sent in the second mobile wireless network to be transmitted only to the access of the first mobile wireless network. node. This can be achieved by using a dedicated IP address at the end of the tunnel between the first and second mobile wireless networks. It is also possible to adopt a special address allocation technology for mobile users in the second mobile wireless network. In addition, this can also be verified by testing the tunnel destination address of the access node of the first mobile wireless network and checking the predetermined access address in the access node of the second mobile wireless network.

The second mobile wireless network may be operated by an operator of the first mobile wireless network, or may also be operated by another operator. In the second case, the operator of the second mobile wireless network does not need to perform user management, that is, it does not need to provide authentication functions or charge users. For settlement with the operator of the first mobile wireless network, for example, an inter-operator charge may be performed, that is, roughly calculated based on the total amount of data transmitted by the network operator of the first mobile wireless network.

In the case of combining the 2G/3G mobile wireless network as the first mobile wireless network and the WLAN mobile wireless network as the second mobile wireless network, the GGSN from the mobile terminal (MT) to the 2G/3G mobile wireless network can be realized The total connection, including the connection via WLAN as an extension of the GPRS secondary PDP context. Among them, the possibility of a mobile terminal is understood as that one IP address can be used to form multiple connections with the GGSN. This can be distinguished in particular in, for example, guaranteed bandwidth quality of service (QoS). In this way, standard Internet services such as WEB browsing and e-mail are handled in the first context, and sound is transmitted through the IP phone connection in the second (secondary) context. As a result, for the 2G/3G mobile wireless network, for example, only minor technical changes in the GGSN are caused.

The heterogeneous mobile wireless system according to the present invention does not require a new protocol. It can work with already known protocols such as MIP and/or GTP. In particular, the control between a mobile terminal and each access node can be implemented only with mobile IP. As a result, it can be controlled in accordance with standard IETF technology without the need for special system changes.

In the case that the mobile wireless network is an overlapping network of the second mobile wireless network, because the connection between the first mobile wireless network and the mobile terminal is not abandoned under the condition of using the second mobile wireless network, it can continue to be safe Important data is transmitted through the first mobile wireless network. For example, when Internet download is performed through the second mobile wireless network (preferably WLAN), the asymmetry of the service is also realized in the downlink toward the first mobile wireless network (preferably 2G/3G mobile wireless network).

In addition, the present invention also relates to a method for providing services from a packet data network for a mobile terminal of a mobile wireless system. The method has at least the following steps: a. At least one first and one second mobile wireless network are provided. Each mobile wireless network includes at least one access node to the packet data network; b. The mobile wireless network is combined in such a way that data packets between the second mobile wireless network and the packet data network can only indirectly pass through the first The access node of a mobile wireless network is transmitted.

Preferably, through the control function in the second mobile wireless network access node, the data packets to be sent in the second mobile wireless network are only transmitted to the access node of the first mobile wireless network.

In addition, a technical problem to be solved by the present invention is to provide a mobile terminal for using a heterogeneous mobile wireless system having at least one first mobile wireless network and one second mobile wireless network.

This technical problem is solved by independent claim 13. Other advantages of the mobile terminal according to the invention are given in the dependent claims 14 and 15.

According to claim 13 of the present invention, there is provided a mobile terminal using a heterogeneous mobile wireless system having at least one first mobile wireless network and a second mobile wireless network, wherein the mobile The terminal can maintain the connection with the first mobile wireless network and the second mobile wireless network at the same time.

Preferably, the mobile terminal can selectively transmit data through the first and/or second mobile wireless network.

Preferably, the user of the heterogeneous mobile wireless system maintains the connection in the first and second mobile wireless networks at the same time. As a result, no data is lost in the case of handover. The usual data forwarding function in the mobile wireless network during handover is no longer needed here, because the mobile terminal can take over this function. Switching the data stream from the first mobile wireless network to the second mobile wireless network and vice versa will be signaled in each mobile wireless network, so that the mobile terminal can simplify the sequence of data security.

In another preferred embodiment of the mobile terminal, the data streams transmitted through the first and second mobile wireless networks can be combined in the mobile terminal.

Preferably, the data streams transmitted through the first and second mobile wireless networks are combined in the mobile terminal. As a result, the handover function of the mobile wireless system is greatly reduced. Because it is preferable not to give up the connection between the first mobile wireless network and the mobile terminal, only a partial handoff occurs between the first and second mobile wireless networks, thereby reducing the amount of data that must be transferred between the mobile wireless networks It is the smallest and greatly simplifies the signal for handover.

The purpose of the present invention is mainly related to embedding a second optional mobile wireless network into a first mobile wireless network, especially a 2G/3G mobile wireless network such as GPRS.

In summary, the advantage of the present invention is particularly that in the heterogeneous mobile wireless system according to the present invention, only partial handover occurs between mobile wireless networks. The handover function is provided in the mobile terminal. In the present invention, the generalization (Verallgemeinerung) of the concept of the secondary PDP context can be realized. In addition, according to the present invention, the home agent function is preferably combined with the access node, preferably with the GGSN. In addition, according to the present invention, a control function is preferably integrated in the access node of the second mobile radio network, which control function forces the routing of data packets to the access node of the first mobile radio network.

Description of the drawings

The other advantages of the heterogeneous mobile radio system according to the invention and the method according to the invention are by means of

detailed description

Figure 1 shows a heterogeneous mobile radio system 1 according to the present invention. The system has: a first mobile radio network 2, preferably a 2G/3G mobile radio network such as GSM GPRS and/or UMTS GPRS; and a second Mobile wireless network 3, such as a WLAN. The first mobile wireless network 2 includes an access node 4, which is in GSM GPRS and/or UMTS In the case of GPRS, it is a GGSN. The home agent function is integrated in the access node. The second mobile wireless network 3 also has an access node 5. The role of the two access nodes 4 and 5 is to access the router. A data tunnel 6 is formed between the access nodes 4 and 5. In order to form the data tunnel 6, the mobile terminal 7 must inform the access node 5 of the second mobile wireless network 3 of the address of the access node 4 of the first mobile wireless network 2. There are different possibilities here. On the one hand, the access node 4 (for example, a GGSN) of the first mobile wireless network 2 can allocate its address or the address of the home agent through the first mobile wireless network 2 (preferably a 2G/3G mobile wireless network) using MIP. It is called a home agent advertisement (Advertisement), or the mobile terminal 7 can use MIP to inquire about the address, which is a so-called home agent request (Solicitation). In the latter case, the access node 4 (preferably a GGSN) answers the query with its own address and does not redistribute the address to other routers. The information exchange between the access node 4 and the mobile terminal 7 can also be implemented using other protocols or protocol extensions. However, the address of the access node 4 may also be a component of the PDP context data stored in the mobile terminal 7. It is also conceivable that the mobile terminal 7 only recognizes the address of the node serving the mobile terminal 7 of the first mobile wireless network 2, and the first mobile wireless network 2 also recognizes the address of the access node 4. The mobile terminal 7 sends the address of the node serving the mobile terminal 7 to the access node 5, and the access node inquires the node served by the first mobile wireless network for the address of the access node 4.

Fig. 2 shows a detailed schematic diagram of another heterogeneous mobile wireless system according to the present invention. Two variants of the mobile radio system according to the present invention will be explained below with reference to FIG. 2.

In the first variant, the packet distribution function 9 is implemented in the access node 4 (preferably GGSN) of the first mobile wireless network 2 as an extension of the GPRS secondary PDP context concept. The mobile terminal 7 enters the first mobile wireless network 2, which in the illustrated case is a 2G/3G mobile wireless network. In addition, the mobile terminal 7 establishes at least one PDP context with the Internet service provider 8, and obtains an IP address (hereinafter referred to as: IP-mt) from the address area. This context is regarded as "always on" in order to guarantee the access of the mobile terminal 7 and the possibility to exchange signal messages with the Internet at least for specific services. The mobile terminal 7 can establish other secondary PDP contexts for the same IP address, so as to reserve a bandwidth on the wireless interface for a specific service, for example. Here, the service flow template for the service determined by the secondary PDP context is described. It characterizes the parameter group of a specific data stream and allows a grouping assignment function in the GGSN, which categorizes and assigns data packets to each data stream, that is, the (secondary) PDP context. The mobile terminal 7 recognizes the existence of another second mobile wireless network 3 and decides to use it. To this end, the mobile terminal 7 establishes a connection with the access node 5 of the second mobile wireless network 3. In the case shown, the latter is a WLAN, where the access node 5 is marked as a local mobile agent (LMA). Get an IP address from there. Mobile terminal 7 signals to GGSN A packet distribution function 9 in 4, it hopes to realize the Internet service for its IP address IP-mt through the second mobile wireless network 3. This can be achieved through 2G/3G mobile wireless network 2 and WLAN 3. When sending a signal through the WLAN 3, the mobile terminal 7 uses MIP or other protocols to send a request to the LMA 5, and the LMA 5 converts the request into a so-called request message for establishing a PDP context. In order to be able to provide the LMA 5 with the session parameters required for constructing the PDP context from the LMA 5 to the GGSN 4, the mobile IP can be supplemented with a session-specific extension. Here, it gives GGSN 4 and its own address as the target address for the tunnel end point. Thus, a connection between LMA 5 and GGSN4 is established. The control message of the 2G/3G mobile wireless network 2 is used when the signal is sent through the 2G/3G mobile wireless network 2. To this end, the existing mechanism must be extended, such as an effective secondary PDP context, so that the address of LMA 5 can be transmitted to GGSN 4, and a corresponding service network node of the 2G/3G mobile wireless network 2 must be indicated that there is no need to establish New context. So GGSN 4 is established to LMA One of 5 has a new tunnel 6 corresponding to the tunnel endpoint address. The tunnel 6 can use the GTP protocol as an encapsulation technology, which forms the smallest scale for changing the function of the GGSN. Thereafter, the entire downlink traffic is transmitted through the tunnel 6. In order to simplify the data coordination in the mobile terminal 7, an endpoint for sending a signal service can be implemented on the old data path 10. The GGSN 4 charges for the new data path (that is, the extra marked through the tunnel 6), for example, as a new QoS class. As long as this new data path is established through the tunnel 6, it can also be used by the mobile terminal 7 for uplink services. LMA 5 directs all uplink data to GGSN 4. Through the corresponding setting of the service flow template, the mobile terminal 7 can control whether to transmit all data or only a specific part of the data from the GGSN 4 to the mobile terminal 7 through the mobile wireless network 2.

In the second variant, the packet distribution function 9 is implemented in the GGSN 4 through the integrated home agent 9, which has a direct interface to the GPRS function of the GGSN 4. The mobile terminal 7 enters the 2G/3G mobile wireless network 2 and establishes at least one PDP context with the Internet service provider 8, and obtains an IP address (hereinafter referred to as: IP-mt) from the provider's address book. This context is again regarded as "always on" in order to ensure that the mobile terminal 7 can be accessed and at least signal messages for specific services can be exchanged with the Internet. The mobile terminal 7 can establish other secondary PDP contexts for the same IP address, so as to reserve a bandwidth on the wireless interface for a specific service, for example. IP-mt is automatically entered as the home address in the integrated home agent 9. The mobile terminal 7 recognizes the existence of another second mobile wireless network 3 and decides to use it. To this end, the mobile terminal 7 establishes a connection to the LMA5. Get an IP address from there. The mobile terminal 7 signals the packet distribution function 9 or the home agent 9 in the GGSN 4 that it hopes to implement Internet services for its IP address IP-mt through the LMA5. This can be achieved through 2G/3G mobile wireless network 2 and WLAN 3. As described in the first variant, the signal is sent to the LMA 5 via the WLAN 3. From LMA 5 to GGSN 4 It is preferable to use a mobile IP. When sending a signal through the 2G/3G mobile wireless network 2, a MIP request can be sent as a regular L3 IP service, where the home agent address corresponds to the GGSN address. An advantage here compared to sending signals via WLAN 3 is that a protected and certified path is used. The GGSN 4 must filter out the MIP message sent to it from the user data stream and deliver it to the internal home agent 9. Among them, GGSN 4 performs a test to see whether the user home address used in the MIPHA registration request is consistent with the IP address of the PDP context used, which implements the authentication and authorization functions in a simple manner. In the case that the mobile terminal 7 sends a signal through the WLAN 3, the GGSN 4 must check whether there is a valid PDP context for the mobile terminal 7, and whether the mobile terminal 7 and its IP-mt are authenticated and authorized by the requirements. Desired service. In addition to the IP address, the mobile IP registration request should also contain the identification of other mobile users to prevent unauthorized users from using the IP address. The integrated home agent 9 establishes a MIP tunnel 6 as a new data path to the LMA 5. Thus, the entire downlink service or the specific data flow corresponding to the service flow template is transmitted via the tunnel 6. In order to simplify the data coordination in the mobile terminal 7, an endpoint for sending a signal service can be implemented on the old data path 10. GGSN 4 Carry out charging for the new data path (that is, the extra marked through the tunnel 6), for example, as a new QoS class. As long as this new data path is established through the tunnel 6, it can also be used by the mobile terminal 7 as an uplink service. LMA 5 transmits all uplink data to GGSN 4. In addition to encapsulating the external agent function of the downlink service, the LMA 5 must also encapsulate all the uplink services and send them to the GGSN 4 and the integrated home agent 9 via the tunnel 6 so that full charging can be performed there. This function is called reverse tunneling. At the same time, it is necessary to prevent the mobile terminal 7 from performing route optimization, and avoid direct routing between the LMA 5 and a corresponding host without passing through the GGSN 4 or the home agent 9. This can be achieved in such a way that the LMA 5 abandons the MIP message corresponding to the route optimization of the mobile terminal 7 or signs it as a passive sign.