CN1726727A - Method and apparatus for performing inter-technology handover from WLAN to cellular network - Google Patents

Abstract

A method, system and computer program are disclosed to perform a low latency inter-technology handoff of a MN from a WLAN to a cellular network. The method includes transmitting a Bearer Context from the MN for use by the cellular network, the Bearer Context containing information required to establish access network bearers in the cellular network for an ongoing Internet session of the MN; and responding to the Bearer Context with a Router Advertisement that is forwarded to the MN. The Bearer Context may be piggybacked on another message, or it may be sent as a separate message. The Bearer Context includes information expressive of: (a) a QoS requirement of an ongoing application or applications of the MN; (b) a unique identity of the MN that is recognizable by the cellular network; (c) parameters to facilitate the creation of a Point-to-Point Protocol state in the cellular network; and (d) parameters to enable establishment of packet filters in the cellular network.

Description

Method and apparatus for performing inter-technology handover from WLAN to cellular network

Cross References to Related Applications

This application claims priority to US Provisional Patent Application No. 60/425,801, filed November 13, 2002, which is hereby incorporated by reference in its entirety.

technical field

The present invention relates generally to wireless communication systems and methods, and more particularly to techniques for handover of mobile nodes (MNs) between wireless network providers operating with different technologies, such as wireless local area networks ( WLAN) and cellular networks.

Background technique

Cellular wireless technologies, such as cdma2000 and Universal Mobile Telecommunications System (UMTS), are expected to provide mobile users with high-speed wireless Internet connections over a wide coverage area. At the same time, WLAN technologies, such as IEEE 802.11 and European HiperLAN, are becoming more common because they provide a low-cost, high-speed wireless access solution for localized "hotspots." According to a forecast for the future of mobile networks, wide-area cellular networks and WLANs will complement each other to provide ubiquitous high-speed wireless Internet connections to mobile users. In such an environment, mobile users can expect to experience a need to seamlessly switch between WLAN and cellular networks, even while an Internet session is in progress.

Soon it will be possible to obtain mobile terminals combining different radio interfaces, eg cellular network and WLAN, in one device, here also referred to as mobile nodes. Furthermore, the development of mobile-aware Internet protocols has accelerated in recent years. These and other factors will combine to converge in the near future to provide enhanced mobile user characteristics and connectivity. However, this will require handling and resolving inter-technology handovers, for example from WLAN to cellular. In particular, when the mobile node moves from the WLAN to the coverage area of the cellular network, it will be found that the WLAN signal decays rapidly. As a result, the time and signal margin available to perform the handover or handover procedure is small.

The Internet Engineering Task Force (IETF) has developed a Mobile IP protocol to enable IP layer switching during an ongoing Internet session. In order to minimize the interruption of the Internet connection of the mobile node during this handover, some protocols are being developed, such as Fast Handoff and Context Transfer. Although these protocols provide the core framework for seamless handover between technologies, applying them to specific environments requires additional efforts. Furthermore, these protocols assume a "trust" relationship between the source (eg WLAN) and destination (eg cdma2000) access networks, which is not suitable in all cases.

Contents of the invention

The foregoing and other problems are overcome, and other advantages are realized, in accordance with presently preferred embodiments of the present invention.

The present invention provides a method for inter-technology handover of a mobile node from a WLAN to a cellular network in preferred but not limited circumstances. This handover process enhances the basic IP layer handover technology in the following areas: (i) fast establishment of access network bearer in the cellular access network; and (ii) dynamic authentication and authorization with the cellular network during handover.

The advantage of this approach is that it does not require major modifications to existing cellular network protocol architectures. In addition, the method is suitable for handover technologies at the IP layer, such as low-latency mobile IPv4 and fast mobile IPv6.

The present invention discloses a method, system and computer program for performing low-latency inter-technology handover of a MN from a WLAN to a cellular network. The method includes, sending a Bearer Context (Bearer Context) from the MN for use in the cellular network, the Bearer Context including information required to establish an access network bearer for the ongoing Internet session of the MN in the cellular network; and The bearer context responds to a Router Advertisement (RouterAdvertisement), which is forwarded to the MN. The Bearer Context can be attached to another message, or sent as a separate message. The Bearer Context includes information to express: (a) the ongoing QoS requirements of one or more applications of the MN; (b) the unique identification of the MN identifiable by the cellular network; and (d) parameters enabling the establishment of packet filters in the cellular network. The method also includes authentication and authorization with the target cellular network for the purpose of performing the handover.

Description of drawings

The foregoing, as well as other aspects of the invention, will be more apparent from the following detailed description of the preferred embodiments when read in conjunction with the accompanying drawings, in which:

Figure 1 is a simplified block diagram of a first, most preferred, embodiment of a reference network architecture and illustrates one suitable type of multi-technology wireless system architecture in which the present invention may advantageously be deployed;

Figure 2 is a simplified block diagram of a second, less preferred, embodiment of a reference network architecture and illustrates another suitable type of multi-technology wireless system architecture in which the present invention may advantageously be deployed;

Figure 3 illustrates a typical indoor WLAN environment within the coverage area of a cellular network; and

Fig. 4 is a message diagram showing the handover signal flow among MN, WLAN and cellular network technologies according to one aspect of the present invention.

Detailed ways

Those skilled in the art will appreciate that the following disclosure contains information relevant to the present invention and may be incorporated into this patent application in whole or in part if necessary: IETF Mobile IP Working Group (www.ietf.org): Low Latency Mobile IPv4 and Fast Mobile IPv6 Specification; IETF Seamody Working Group (www.ietf.org): Context Transfer Framework Specification; 3GPP2 Specification: "Wireless IP Architecture Based on IETF Protocol" (3GPP2#P.R0001) and "Wireless IP Network Standard (3GPP2#P.S0001-A v3.0)", www.3gpp2.org; 3GPP2 specification: "Access Network Interface Interoperability Specification", RevisionA (3G-IOSv4.1), 3GPP2#A.S0001 -A, www.3gpp2.org; 3GPP Specification: "QoS Concepts and Architecture", TS 23.107, www.3gpp.org; and 3GPP Specification: "General Packet Radio Service: Service Description", TS 03.60, www.3gpp. org.

Figure 1 shows a reference network deployment implementation, which is also called an independent AAA (Authentication, Authorization, Accounting) implementation. For purposes of illustration, and not limitation, the cdma2000 specification is used in FIG. 1 as a representative of the Cellular 2 architecture. In the architecture of Figure 1, access to WLAN 1 and access to cdma2000 network 2 are managed independently, and no peer-to-peer relationship (such as co-ownership or roaming agreements, for example) exists between the two. A non-limiting example of such an arrangement is a WLAN hotspot in a bookstore that charges the user's patron account for access. Another example is an enterprise's WLAN, to which only employees of the enterprise are authorized to access (ie, no access charges for employees). Or, in some cases, WLAN access at the hotspot may be free, and therefore, no local AAA functionality is required at the WLAN. This is the case, for example, with a WLAN hotspot in a small restaurant. On the other hand, cdma2000 cellular access is usually charged to the user's subscription account by the (home) cellular operator.

In the illustrated example, there are multiple domains 5 in each of the WLAN 1 and the cdma2000 network 2. For example, a WLAN 1 includes a home agent domain 6, and a WLAN AAA function 7 connected to a WLAN access point 9 through an access router (AR) 8. The cdma2000 network 2 may include an AAA functional unit 10 located in the home operator network (Home Operator Network), and a local AAA functional unit 11 in the visited cdma2000 network, the local AAA functional unit 11 is connected through a PDSN (packet data support node) 12 to the IMT-2000 wireless network13. Assume that MN 3 switches from WLAN 1 to cdma2000 network 2 through WLAN access point 9 and IMT-2000 wireless network 13.

Figure 2 shows another network deployment implementation, called shared AAA architecture. Here, it is assumed that there is a trust relationship between WLAN 1 and cdma2000 network 2. Note the overlapping domains 5A and 5B in this embodiment. For example, this embodiment would exist if the WLAN hotspot access was operated by a cdma2000 operator. Alternatively, there is a roaming agreement between the WLAN 1 operator and the cdma2000 network 2 operator. Therefore, the authentication and authorization performed by WLAN 1 can also be reused for cdma2000 network 2 access when switching between technologies. Furthermore, there will be a security association 5C between the AR 8 in the WLAN 1 and the PDSN 12 in the cdma2000 network 2. For completeness, outside the mutually trusted WLAN/cellular network arrangement, there is shown another operator 14 with an access router 15 connected to the WLAN access point 9 .

Of most interest to the present invention is the standalone network architecture shown in FIG. 1 . However, it should be noted that the handover method of the present invention is also applicable to the shared deployment model in FIG. 2 .

Referring again to FIG. 1 , consider a handover from WLAN network 1 to cdma2000 network 2 . In such an environment, assume that a mobile user initiates an Internet (Internet) 4 session, such as a Voice over IP (VoIP) call or a multimedia conference call, from WLAN 1, and later leaves from the WLAN hotspot coverage area. Before attempting to handover between technologies from WLAN 1 to wide area cdma2000 network 2, MN 3 should first perform authentication and authorization procedures with cdma2000 network 2. Note that the Home Agent 6 for the MN 3 may be located in the same area as the WLAN 1 (e.g. in the case of an enterprise), or in the same area as the Home Operator Network 2, or in a completely different area (e.g. in the case of an enterprise) bookstore or free access).

In addition, before the MN 3 can exchange IP packets with the Internet 4 through the cdma2000 access network 2, several procedures should be performed, including procedures for IP access and quality of service (QoS) settings. These include procedures for establishing a PPP (Point-to-Point Protocol) connection with the PDSN 12, Mobile IP procedures and procedures for establishing an access network bearer with suitable QoS characteristics in the cdma2000 network 2.

The delay in performing these procedures should be minimized to avoid service interruption when switching from WLAN 1 to cdma2000 network 2, for example during an ongoing session, such as a VoIP session, or a multimedia streaming session, or a contest session. The present invention provides a technique to perform inter-technology switching efficiently and quickly, avoiding the problems inherent in the prior art.

Generally, the performance of the handover can be considered to be considerably improved if at least some of the handover messages are actively performed, i.e. while the MN 3 can still see a strong signal from the WLAN access point 9. These actively performed steps may include, for example, fast handover signaling, and cellular network 2 authentication, and informing the cellular network 2 of the QoS and other requirements currently applied by the MN 3. Then, once the WLAN signal strength decreases, have the MN 3 send a final trigger to the cellular network 2 to complete the handover procedure (i.e., actually allocate radio resources, arrange for rerouting of packets, and perform any other necessary steps to complete the handover process).

It should be noted that it is generally not possible to perform this task reliably based on MN 3 signal strength metrics alone. For example, if the active handover procedure is initiated after the WLAN signal strength begins to drop significantly, the MN 3 Internet connection will be interrupted before completing these steps. On the other hand, if the handover process is initiated too early (while the WLAN signal is still strong), a large number of false starts will result. In other words, even though the active handover procedure has started, the mobile user does not actually leave the coverage area of WLAN 1 at all. This will increase the unnecessary signaling load of the cellular network 2 .

Referring to FIG. 3, an exemplary WLAN/cellular network environment is shown, such as would be encountered in a hotel or other type of establishment. In FIG. 3 it can be seen that a cellular network (eg, cdma2000 network) base station footprint 20 includes a structure 22 containing a plurality of WLAN access point (AP) footprints 24 .

The present invention provides an inter-technology handover technique, which can be clearly divided into active steps and passive steps. In addition, the present invention also provides a method that can foresee the demand for handover from WLAN 1 to cellular network 2, so that there is enough time to execute the active switching step. In this regard, a handover trigger mechanism is required for initiating the Phase 1 and Phase 2 aspects of the handover technique (the operations of Phase 1 and Phase 2 will be detailed below).

Wherein, the signal strength criterion can be used to generate a handover trigger, and the signal strength criterion can be used to generate a final handover trigger. However, in the context of handover from WLAN to cdma2000, this method may generate spurious handover triggers. For further illustration, consider the handover scenario depicted in Figure 3, which shows a WLAN coverage area in a hotspot, which in this case is an indoor environment, such as a hotel (structure 22). Areas 24A and 24B represent strong signal coverage areas of different WLAN APs located in hotspots. Note that the geographic coverage area of WLAN 1 is contained within the geographic coverage area of cdma2000 network 2, which is a typical situation. Assume that a mobile user with a multi-radio (eg, dual-mode WLAN and cdma2000) MN 3 initiates an Internet session through WLAN access, and then walks along path 26. Along path 26, when the user arrives at a specific area where the WLAN signal strength drops due to local factors such as metal objects, walls, etc., the MN 3 detects the drop in WLAN signal strength, but can still detect a strong cellular signal. In this case, MN 3 will try to initiate a handover from WLAN 1 to Cellular 2. However, a few seconds or a moment later MN 3 detects a strong signal from WLAN 1 again, and therefore, needs to initiate a handover back to WLAN 1. Such a ping-pong effect is undesirable because it would bring unnecessary signaling traffic and possibly cause more disruption to user services than would be caused by a momentary loss of WLAN signal. Of course, MN 3 may wait for a short time before initiating a handover to Cellular 2 after the WLAN signal loss. However, this approach degrades the (latency) performance of the handover when the user actually leaves the structure 22 through the door 22A, and thus actually loses the connection to the WLAN mesh 1 .

Thus, while signal strength criteria are used to initiate the inter-technology handover and produce the final WLAN/cellular handover, those skilled in the art will recognize that other considerations and criteria may be used, such as packet error rate and/or The number of retransmission requests, and other parameters related to signal quality, instead of or in combination with the use of the received signal strength at MN 3.

Another technique, currently more preferred for performing active handover control, relies on the use of "boundary bits", i.e., information provided by border access nodes, providing geographic coverage or area Switching from one technical network to another. Reference is made in this regard to U.S. Provisional Patent Application No. 60/426,385, entitled "Smart Inter-Technology Handover Control," by H. Chaskar et al., the entire contents of which are incorporated by reference.

What will now be described is a handover procedure specifically related to the cdma2000 Net 2 architecture, which operates in accordance with the present invention.

First described is a handover procedure suitable for Low-Latency Mobile IPv4 in "pre-registration" mode (IETF Mobile IP Working Group: "Low-Latency Mobile IPv4 and Fast Mobile IPv6 Specifications", www.ietf. org). This mode is useful since Mobile IPv4 has been introduced into the cdma2000 specification. The corresponding signaling scheme is shown in FIG. 4 . The basic idea of the present invention adapted to fast mobile IPv6 (in "predictive handover" mode) is similar and a description of this embodiment is also given below.

Referring now also to Figure 4, after MN 3 decides to initiate an inter-technology handover from WLAN 1 to cdma2000 network 2 (based on adopting any suitable parameters, such as signal strength and/or signal quality and/or use of boundary bits), it passes The wireless connection sends a Proxy Router Solicitation (ProxyRtSol) to the AR 8, and then the AR 8 sends a Router Solicitation to the PDSN 12 via the Internet 4. Furthermore, the MN 3 arranges to transfer a message called "Bearer Context" to the PDSN 12 via the AR 8. The bearer context message contains parameters for establishing an access network bearer in the cdma2000 network 2 for the ongoing Internet session of the MN 3. The Bearer Context message can be attached to the ProxyRtSol or other message sent from the MN 3 to the AR 8, or it can be sent as a separate message. From AR 8 to PDSN 12, the Bearer Context message can be attached to the Router Solicitation message, or it can be sent as a separate message. Bearer context messages include at least one or more of the following similar or equivalent information:

The QoS requirements of the ongoing application of the MN, such as one or more required bandwidth, reliability and delay characteristics,

MSID: the mobile station identification code that can be identified by cdma2000 network 2, for example, the IMSI (International Mobile Subscriber Identity code) of MN 3,

LCP (Link Control Protocol) configuration parameters such as MRU (Maximum Receive Unit),

ACCM (Asynchronous Control Character Mapping) and a link quality monitoring protocol to be used to facilitate the creation of PPP states in the PDSN 12,

TFT (Traffic Flow Template) to enable the establishment of packet filters in the PDSN 12, and any other required service parameters, such as the requested security level.

The aforementioned parameters constituting the bearer context message cannot be viewed in a restrictive manner. For example, other parameters requesting resources from the cellular network 2, such as location tracking services and/or transcoding services for a particular packet session, may also be provided within the scope of the invention, or instead of one of the aforementioned parameters.

The PDSN 12 responds to the Bearer Context message with a Router Advertisement message, which is forwarded to the MN 3 via the Internet 4 and the AR 8 (as a Proxy Router Advertisement or ProxyRtAdv). Among them, ProxyRtAdv includes a challenge (eg, Mobile Node-Foreign Agent (MN-FA) challenge extension) for authentication and authorization purposes.

MN 3 sends a registration request (RegReq) message to PDSN 12 via AR 8 to respond (as shown in step 2 in Figure 4). Among other things, the message contains the MN 3 Network Address Identifier (MN-NAI), which identifies the MN 3's home AAA, the authentication data to be used for registration with the Home Agent 6, and the MN-FA challenge calculated by the MN-FA received in ProxyRtAdv The response (MN-Radius extension) is used for the purpose of authentication and service authorization with cdma2000 network 2. It should be noted that a Bearer Context message can be appended to this message if it has not been sent before.

Upon receiving the Registration Request, the PDSN 12 uses the NAI extension to determine the home AAA domain of the MN 3 and issues a query to the identified home AAA 10 of the MN 3. In a preferred embodiment, the PDSN 12 actually queries the local (visited) AAA 11 in the cdma2000 network 2. The visiting AAA 11 then forwards the inquiry to the home AAA 10 of the MN 3, possibly via one or more intermediate transit AAAs. The PDSN 12 provides the home AAA 10 with the challenge issued by the PDSN 12 in the MN-FA challenge extension, and the MN 3's answer to the challenge obtained in the MN-Radius extension. The PDSN 12 also provides the Home Agent AAA 10 with a description (eg QoS) of the access service requested by the MN 3. Upon successful authentication and service authorization, the Home Agent AAA 10 sends a success indication to the PDSN 12 (the response will usually follow the same path as the query, but in the opposite direction) to authorize access by the MN 3. The Home Agent AAA 10 also sends "tickets" to the PDSN 12 in clear text as well as in encrypted form. The ticket is encrypted using a secret shared between the home AAA 10 and the MN 3. These processes are shown in step 3 of Figure 4.

As shown in step 4, PDSN 12 stores the ticket in plain text and sends an encrypted copy to MN 3 via AR. PDSN 12 also sends all configuration parameters for MN 3 in this message. At this point, the first phase (Phase 1 ) of the inter-technology handover process can be considered complete.

MN 3 sends an acknowledgment response (ACK) to PDSN 12 via AR 8, and the ACK includes a ticket in plain text (step 5 of Figure 4), thereby proving to PDSN 12 that the ACK is indeed from MN 3, and at this time the inter-technical exchange begins The second phase of the handover process (phase 2). This is a security measure that helps avoid Denial of Service (DOS) attacks, where a malicious node spoofs an ACK, causing the burden of false bearers to be established on the cdma2000 network2.

It should be noted that there may be a time delay between the completion of Phase 1 and the start of Phase 2. This can happen if the MN 3 starts Phase 1 while the WLAN signal is still fairly strong (but fading) and wants to complete Phase 1 before losing connection to the Internet 4. Phase 2 will usually start when the MN 3 is about to leave the WLAN coverage area 24. After sending ACK, MN 3 just waits to receive information from cdma2000 network 2.

While MN 3 is waiting, cdma2000 network 2 executes A10/A8/A1 bearer establishment (step 6 of Figure 4), just like cdma2000 specification, 3GPP2 access network interface interoperability specification (3G-IOS v4.0.1) Release A (1999) Revision 0, 3GPP2#A.S0001-0.1, as described in the "Network Initialization Bearer Establishment" chapter. Furthermore, the PDSN 12 performs registration with the HA 6 of the MN 3 in step 7. Upon receiving the Registration Reply (RegRep) from HA 6, PDSN 12 forwards it to MN 3 via one of the established access bearers.

As another implementation of the process in step 4 of FIG. 4, the home AAA 10 may generate the session key, both in plaintext and in encrypted form (e.g., using a secret shared between the MN 3 and the home AAA 10) Forward it to PDSN 12. PDSN 12 stores the plaintext key and forwards the encrypted version to MN 3 (via PDSN 12 and AR 8). The MN 3 can then use this key to authenticate or encrypt future messaging (e.g., ACKs) with the PDSN 12.

What is now described is a technique to adapt the aforementioned handover implementation to the Fast Mobile IPv6 environment (IETF Mobile IP Working Group: "Low Latency Mobile IPv4 and Fast Mobile IPv6 Specification", www.ietf.org). In this method, the communication between the AR 8 and the PDSN 12 in step 1 of FIG. The MN-FA challenge is attached to the HI and HACK messages respectively. In this case, a new message can be used to perform step 2, wherein MN 3 sends a response for authentication and authorization of cdma2000 network 2. Such a message has not been included in the Fast Mobility IPv6 protocol because the protocol design assumes a strong security association between the AR 8 and the PDSN 12. In step 4, another new message can be used to send the ticket to MN 3, while the ACK in step 5 can be sent to AR 8, using an F-BU (fast binding update) message and attaching the ticket on it. Another new message can be used for the AR 8 to send an indication to the PDSN 12 to initiate step 6. In step 6, PDSN 12 did not perform registration with HA 6. Furthermore, a temporary tunnel is preferably established between AR 8 and PDSN 12 until MN 3 performs a binding update.

While the foregoing has been described in connection with certain presently preferred embodiments, it should be appreciated that the practice of the invention is not limited to these embodiments. For example, the bearer context can be sent by the MN 3 with context transfer signaling. As another example, and as mentioned above, in addition to those mentioned above, other traffic specification parameters may be included in the bearer context message, such as location tracking traffic and transcoding traffic for a particular packet session. As another example, the bearer context message may be encrypted using a secret shared between the MN 3 and the home AAA 10. This can help prevent leakage of secrets through the AR 8 to PDSN 12 path. When the PDSN 12 receives the encrypted bearer context, it passes the encrypted bearer context to the home AAA 10 in query mode. The home AAA 10 deciphers the encrypted bearer context and sends it to the PDSN 12 in response.

It should also be understood that the present invention includes computer program code, embodied in a tangible medium, for instructing one or more data processors to perform the various steps of the methods described above. These data processors may reside at least in the MN 3 and PDSN 12, or in equivalent cellular network nodes and functional components.

Although described in connection with a WLAN/cdma2000 cellular network, it should be understood that the teachings are applicable to other types of wireless systems as well, for example, the teachings of the present invention are also applicable to digital TDMA and FDMA systems. Furthermore, while described in connection with various specific messages, message names and message types, it should be recognized that these are exemplary and are not to be construed as limitations on the practice of the invention. For example, a message sent from the MN 3 is called a context bearer message for convenience, but may be called another name.

Claims (41)

1. method is used to carry out between the technology of the low time delay of mobile node (MN) from the wireless lan (wlan) to the Cellular Networks and switches, and this method comprises:

The loading context information of sending from described MN is used for described Cellular Networks, and this loading context information comprises the information that is used for setting up for the ongoing grouping data conversation of described MN in described Cellular Networks at least one access bearer; And

To receiving described loading context information response router advertisement message, this router advertisement message is transmitted to described MN.

2. according to the process of claim 1 wherein, described loading context information appendix is on another message.

3. according to the process of claim 1 wherein, described loading context information comprises the information of the qos requirement of the ongoing one or more application that are used for expressing described MN.

4. according to the process of claim 1 wherein, described loading context information comprises that be used for expressing can be by the uniquely identified information of the described MN of described Cellular Networks identification.

5. according to the process of claim 1 wherein, described loading context information comprises the information that is used for expressing the help parameter that point-to-point protocol status is created in described Cellular Networks.

6. according to the process of claim 1 wherein, described loading context information comprises and is used for expressing the information that makes it possible to set up the parameter of packet filter in described Cellular Networks.

7. according to the process of claim 1 wherein, described loading context information appendix is on router request message, and this router request message is that response receives from the proxy requests solicitation message of described MN and sends from couple in router (AR).

8. according to the method for claim 7, wherein, described router advertisement sends to described AR, and described in response AR sends agent router and announces to described MN.

9. method according to Claim 8, wherein, described router advertisement comprises the challenge that is used for the authentication and authorization purpose.

10. method according to Claim 8, wherein, described MN responds described agent router announcement by sending login request message to described Cellular Networks.

11. method according to claim 10, wherein, described agent router announcement comprises the challenge that is used for the authentication and authorization purpose, and wherein, described login request message comprises the information of the attribution authentication that is used at the described MN of described Cellular Networks identification, mandate, charging (AAA) functional part and to the response of the described challenge that receives in described agent router announcement.

12. according to the method for claim 11, wherein, response receives described login request message, sends the described ownership AAA of inquiry to described MN.

13. according to the method for claim 12, wherein, described inquiry directly sends via visit AAA, perhaps sends via at least one intermediate transit AAA.

14. method according to claim 12, wherein, the described inquiry that sends to described ownership AAA comprises information of indicating the described challenge that sends to described MN and the described response to described challenge that receives from described MN, is used for by the described MN of described ownership aaa authentication.

15. according to the method for claim 14, wherein, the described inquiry that sends to described ownership AAA comprises the information of indicating the access service that described MN asked.

16. the method according to claim 14 also comprises, response success identity described MN sends the access that the successful indication from described ownership AAA is used to authorize described MN.

17. according to the method for claim 16, wherein, this is successfully indicated and also comprises with expressly and so that be used in the bill that form that the secret shared between described ownership AAA and the described MN encrypts sends.

18. according to the method for claim 17, wherein, the described plaintext form of described bill is stored in the cellular network node, and wherein, the bill of described encryption sends to described MN via described AR.

19. according to the method for claim 18, comprise also sending and reply (ACK) that this ACK comprises described plaintext bill to described Cellular Networks from the affirmation of described MN.

20. according to the method for claim 19, response receives the described plaintext bill from described MN, also is included in to carry out access bearer foundation in the described Cellular Networks, is used to described MN to set up at least one access bearer.

21. method according to claim 20, further response receives the described plaintext bill from described MN, in a single day register described MN to described HA, and receive registration reply, just described registration reply is transmitted to described MN from described Cellular Networks by the access bearer of setting up from described HA.

22. method according to claim 17, also comprise, generate session key at described ownership AAA with plaintext and so that be used in the form of the secret encryption of sharing between described MN and the described ownership AAA, the described plaintext session key of storage in cellular network node, and the described encrypted form of described session key is transmitted to described MN, by described MN use in the following message contact of authentication and encryption and described Cellular Networks at least a.

23. according to the process of claim 1 wherein, described bearer context is sent by the form that described MN uses the secret shared between the attribution authentication, mandate, charging (AAA) functional part of described MN and the described MN in described Cellular Networks to encrypt.

24. according to the process of claim 1 wherein, the communication between described MN and the described Cellular Networks comprises HI/HACK (switching starting/switching ACK) message, and wherein, described loading context information appendix is on described HI message.

25. according to the method for claim 24, wherein, described Cellular Networks responds with mobile node-Foreign Agent (MN-FA) challenge extension of appendix on described HACK message and receives described loading context information.

26. according to the process of claim 1 wherein, described MN sends described loading context information responding a kind of variation, this variation is the signal strength signal intensity relevant with WALN, signal quality and such as at least one variation of the out of Memory of geographical domain information.

27. a data communication system comprises mobile node (MN), wireless lan (wlan) and Cellular Networks, this system also comprises:

Transmitter is used to send loading context information from described MN to described Cellular Networks, and this loading context information comprises the information that is used for setting up for the ongoing grouping data conversation of described MN in described Cellular Networks access bearer; And

To receiving described loading context information response router advertisement message, this router advertisement message is transmitted to described MN.

28. according to the system of claim 27, wherein, described loading context information appendix is on another message.

29. according to the system of claim 28, wherein, described loading context information appendix is on router request message, this router request message is that response receives from the proxy requests solicitation message of described MN and sends from couple in router (AR).

30. system according to claim 28, wherein, communication between described MN and the described Cellular Networks comprises HI/HACK (switching starting/switching ACK) message, wherein said loading context information appendix is on HI message, and wherein, described Cellular Networks is to receiving described loading context information response mobile node-Foreign Agent (MN-FA) challenge extension, and this expansion appendix is on HACK message.

31. system according to claim 27, wherein, described loading context information comprises at least one the information that is used for expressing following aspect: the qos requirement of the ongoing application of at least one of described MN, can be by the unique identification of the described MN of described Cellular Networks identification, the parameter that helps the parameter that point-to-point protocol status is created in described Cellular Networks and make it possible to set up packet filter in described Cellular Networks.

32. according to the system of claim 27, wherein, described loading context information is received by packet data support node (PDSN).

33. computer program, be used to control the operation of mobile node (MN), this node can be operated with wireless lan (wlan) or Cellular Networks, the variation of the WLAN signal strength signal intensity that described computer program response receives and at least one of signal quality, send loading context information from described MN to described Cellular Networks, this loading context information comprises the information that is used for setting up for the ongoing grouping data conversation of described MN in described Cellular Networks at least one access bearer.

34. according to the computer program of claim 33, wherein, described loading context information appendix is on another message.

35. according to the computer program of claim 34, wherein, described loading context information appendix is on router request message, this router request message is that response receives from the proxy requests solicitation message of described MN and sends from couple in router (AR).

36. computer program according to claim 34, communication between wherein said MN and the described Cellular Networks comprises HI/HACK (switching starting/switching ACK) message, wherein said loading context information appendix is on HI message, and wherein said Cellular Networks is to receiving described loading context information response mobile node-Foreign Agent (MN-FA) challenge extension, and this expansion appendix is on HACK message.

37. according to the computer program of claim 33, wherein said loading context information comprises in order to express at least one information of following aspect: the qos requirement of the ongoing application of at least one of described MN, can be by the unique identification of the described MN of described Cellular Networks identification, help the parameter that point-to-point protocol status is created in described Cellular Networks and make it possible in described Cellular Networks, set up the parameter of packet filter.

38. computer program, be used to control the operation of the network node of Cellular Networks, described computer program response receives the loading context information from the mobile node (MN) of current and wireless lan (wlan) wireless connections, begin to described MN sets up the Cellular Networks access bearer, this loading context information comprises the information that is used for setting up for the ongoing grouping data conversation of described MN in described Cellular Networks at least one access bearer.

39. according to the computer program of claim 38, wherein, described cellular network node comprises packet data support node (PDSN).

40. according to the computer program of claim 39, wherein, described Cellular Networks comprises the cdma2000 Cellular Networks.

41. computer program according to claim 38, wherein, described cellular network node is by sending router advertisement message to described MN, and this router advertisement message is drawn together mobile node-Foreign Agent challenge extension message, and response receives described loading context information.

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