The invention relates to interworking between wireless local area networks (WLAN) and 3GPP mobile communication networks, and more precisely to situations in which a mobile station that has a number of applications (sessions) open to service servers interfaced to a 3GPP mobile network core network via different GGSN nodes needs to keep its sessions open on transfer (handover) from a WLAN network to a 3GPP mobile network or vice-versa.
Here “3GPP networks” means all communication networks having a 3GPP radio interface enabling IP (Internet Protocol) access, and especially second generation (2G) mobile (cellular) networks, for example GSM networks, 2.5G mobile (cellular) networks, for example GPRS/EDGE networks, and third generation (3G) mobile (cellular) networks, for example UMTS or CDMA2000 networks, together with all their variants.
Here “wireless local area networks” means all communication local area networks having a WLAN radio interface enabling IP access (IEEE 802.11, Bluetooth and Hiperlan/2 standards) and especially WiFi and WiMAX networks.
Here “(3GPP/WLAN) interworking” means the possibility for a WLAN network to use certain 3GPP core network infrastructures to enable the user of a hybrid (3GPP/WLAN) mobile station, connected to that WLAN network or on the point of being connected thereto, to access packet services offered by one or more Internet service providers (ISP). Such interworking is defined in particular by release 7 of the 3GPP Technical Specifications TS 23.234 and TS 23.934.
As the person skilled in the art knows, release 7 of the 3GPP/WLAN interworking standard (and more precisely its scenario N° 4) addresses continuity of service on handover of a communication session (involving a service) from a WLAN radio access network to a 3GPP radio access network, and vice-versa. In other words, when a mobile station is using a service via a WLAN radio access network, it must be able to continue to use that service if it quits the 3GPP (respectively WLAN) radio access network to continue its call via a WLAN (respectively 3GPP) radio access network.
For example, a mobile station can use a service via a WLAN radio access network when end-to-end tunnels have been established between that mobile station and a tunnel termination gateway (TTG) of a 3GPP core network, on the one hand, and between that TTG gateway and a gateway GPRS support node (GGSN), on the other hand, the latter providing the connection of the 3GPP core network to the IP network offering the service. Another architecture option sets up a tunnel between a mobile station and a PDG type equipment, but the invention does not apply to this option.
A mobile station can use a service via a 3GPP radio access network if tunnels have been established, on the one hand, between that mobile station and a serving GPRS support node (SGSN) of the 3GPP core network and, on the other hand, between that SGSN node and the GGSN node providing the connection of the 3GPP core network to the IP network offering the service.
In a 3GPP network, the GGSN node is considered an anchor point, including when a mobile station is moving from a WLAN network coverage area to that of a 3GPP (mobile) network. Consequently, during a session transfer (handover) from a WLAN network to a 3GPP network, the SGSN node that is contacted to continue the session must determine the identity of the TTG gateway used until then for that session, in order to obtain from the latter the transfer SGSN context, which includes the service PDP (Packet Data Protocol) context, and initiate a PDP context transfer procedure (which corresponds to the mobile station/GGSN node IP connection). Similarly, during a session transfer (handover) from a 3GPP network to a WLAN network, the gateway TTG that is contacted to continue the session must determine the identity of the SGSN node used until then for that session, in order to obtain from the latter the transfer SGSN context and initiate a PDP context transfer procedure.
From the point of view of the core network, the gateway TTG is therefore treated as an SGSN node, which implies that it must support the location management mechanisms, for example SGSN context transfer, service PDP context update and home location register (HLR) update, in order to maintain continuity of service during a transfer (handover).
The drawback of the architecture based on tunnel termination gateways (TTG) described hereinabove is that it is not adapted to situations in which the user of a mobile station is using more than one (active) service simultaneously, and has therefore set up more than one communication session (or opened more than one application). In these multi-APN (access point name) situations, a plurality of gateways TTG can be involved in a plurality of 3GPP packet-switched services. Remember that the connection of a mobile station of a user to a TTG/GGSN pair is linked to an APN that was requested by that user. Consequently, if a user has requested a plurality of APNs for a plurality of sessions, their mobile station can find itself connected simultaneously to a plurality of tunnel termination gateways. An SGSN node being designed only to recover one PDP context in one node, it is therefore not able to support a WLAN/3GPP or 3GPP/WLAN transfer (handover) simultaneously involving a plurality of communication sessions (plurality of applications).
To eliminate this drawback, it would be possible to modify the mode of operation of the SGSN nodes, but that is not very realistic given the large number of SGSN nodes already installed. Moreover, this imposes modifying the home location register HLR in order to store a plurality of attachment points (here tunnel termination gateways) for a mobile station, instead of the usual single SGSN node.
An object of the invention is therefore to propose a solution for maintaining continuity of service on transferring a plurality of communication sessions (open applications) from the same mobile station (using a plurality of services) of a WLAN radio access network to a 3GPP radio access network, and vice-versa.
To this end it proposes a method dedicated to managing interworking between a wireless local area network (WLAN) and a 3GPP mobile network both connected to a core network comprising at least two GGSN nodes connected to respective service networks, at least one SGSN node connected to the mobile network and to the GGSN nodes, and at least two tunnel termination gateways (TTG) connected to the wireless local area network and to the GGSN nodes, respectively.
This method is characterized in that, in the case of generation by a mobile station, having set up at least two communication sessions via tunnels established between the TTG gateways (respectively the SGSN node), and the GGSN nodes, of a message reporting a transfer of the communication sessions from the wireless local area network (respectively the mobile network) to the mobile network (respectively the wireless local area network), it consists in:
i) determining communication identifiers of said TTG gateways, (respectively a communication identifier of the SGSN node),
ii) using an interface equipment, connected to the TTG gateways and to the SGSN node to recover transfer SGSN contexts of the mobile station from the identified TTG gateways, (respectively from the identified SGSN node), and
iii) at the GGSN nodes identified by the received transfer SGSN contexts, updating service PDP contexts intended to eliminate an/or modify the tunnels, and establishing new tunnels between the mobile station and the GGSN nodes via the SGSN node, (respectively the TTG gateways, to assure continuity of service during the transfer of the communication sessions.
The method of the invention can have other features and in particular, separately or in combination:
The invention also proposes interface equipment for a 3GPP core network comprising processor means responsible, if they receive a message requesting transfer SGSN contexts of a mobile station seeking to transfer between the wireless local area network and the mobile network communication sessions set up via tunnels between the GGSN nodes and the TTG gateways (respectively the SGSN node), to recover the transfer SGSN contexts of the mobile station from the TTG gateways (respectively the SGSN node) in order to communicate them to the SGSN node (respectively to the TTG gateways), so that it can be substituted (respectively they can be substituted) for the TTG gateways (respectively the SGSN node), and to establish new tunnels between it (respectively them) and the mobile station.
The interface equipment can have other features and in particular, separately or in combination:
Other features and advantages of the invention will become apparent on reading the following detailed description and examining the appended drawings, in which:
The appended drawings constitute part of the description of the invention as well as contributing to the definition of the invention, if necessary.
An object of the invention is to maintain continuity of service on transferring a plurality of (at least two) communication sessions or applications (involving a plurality of services used simultaneously by a mobile station) from a WLAN radio access network to a 3GPP radio access network and vice-versa.
It is considered hereinafter by way of nonlimiting and illustrative example that the 3GPP radio access network is part of a UMTS type 3GPP mobile (cellular) network. However, the invention is not limited to that type of mobile network. In fact it relates to all communication networks having a 3GPP radio interface enabling IP access and in particular 2G networks (for example GSM networks), 2.5G networks (for example GPRS/EDGE networks), and 3G networks (for example UMTS or CDMA2000 networks), together with all their variants and equivalents.
It is further considered hereinafter by way of nonlimiting and illustrative example that the WLAN radio access network is part of a wireless local area network (WLAN) of WiFi or WiMAX type. However, the invention is not limited to that type of WLAN network. In fact it relates to all wireless local area networks having a WLAN radio interface enabling IP access (IEEE 802.11, Bluetooth and Hiperlan/2 standards).
The invention proposes a method dedicated to the management of interworking between a wireless local area network (WLAN) and a 3GPP mobile network. That method can be implemented by means of a network architecture of the type shown in
It is considered hereinafter that the 3GPP radio access network RAN and the 3GPP core network CRD are part of the same UMTS network of which the users of the mobile stations MS are customers. Consequently, in the example described hereinafter the GPP core network CRD constitutes a home core network for the mobile stations MS. However, this is not obligatory.
It is important to note that the invention relates only to 3GPP/WLAN hybrid mobile stations MS, i.e. mobile stations having a communication card (for example of UICC type provided with a (U)SIM) enabling them to be connected both to WLAN radio access networks (WAN) and to 3GPP radio access networks (RAN). It can therefore be a question of any type of mobile communication equipment and in particular a mobile telephone, a portable computer or a personal digital assistant (PDA) equipped with a card of the type cited above.
The method of the invention must be used each time that a mobile station MS has set up at least two communication sessions with at least two networks (sets) of services RS1 and RS2, through the intermediary of a WLAN radio access network W1 (respectively a 3GPP radio access network RAN) and at least its home core network CRD, in order to use simultaneously at least two different services, and that mobile station MS must be connected to a 3GPP radio access network RAN (respectively a WLAN radio access network W1), where applicable a visited network, in order to continue the communication session used for said services.
The method is therefore applied either when tunnels have been established between a mobile station MS and at least two tunnel termination gateways (TTGs) T1 and T2 (belonging to the core network CRD and connected to the WLAN radio access network W1) and between the latter and at least two GGSN (Gateway GPRS Support Node) nodes G1 and G2 (belonging to the core network CRD and connected to the service networks RS1 and RS2), or when tunnels have been established between a mobile station MS and an SGSN (Serving GPRS Support Node) node NS (belonging to the core network CRD and connected to the 3GPP radio access network RAN) and between the latter and at least two GGSN nodes G1 and G2.
The method of the invention consists in effecting the three phases described hereinafter each time that a mobile station MS that has set up at least two communication sessions via tunnels established between the tunnel termination gateways T1 and T2 (or the SGSN node NS) and the GGSN nodes G1 and G2, generates a message reporting the requirement to transfer its communication sessions from the WLAN radio access network W1 (or the 3GPP radio access network RAN) to the 3GPP radio access network RAN (or the WLAN radio access network W1).
The first phase consists in determining communication identifiers of the tunnel termination gateways T1 and T2 (or a communication identifier of the SGSN node NS).
The second phase consists in using a new interface equipment ED, connected to the tunnel termination gateways T1 and T2 and to the SGSN node NS, to recover transfer SGSN contexts of the mobile station MS from the tunnel termination gateways T1 and T2 (or from the SGSN node NS) identified during the first phase.
The third phase consists in effecting a service PDP context update at the GGSN nodes G1 and G2 identified by the transfer SGSN contexts recovered during the second phase, in order to eliminate and/or modify the tunnels established between the mobile station MS and the GGSN nodes G1 and G2, via the tunnel termination gateways T1 and T2 (or the SGSN node NS), and establish new tunnels between the mobile station MS and the GGSN nodes G1 and G2, via the SGSN node NS (or the tunnel termination gateways T1 and T2), in order to assure continuity of service during the transfer of the communication sessions of the mobile station MS.
The above three phases are described in detail hereinafter in the context of first and second embodiments of the method, respectively corresponding to transferring two communication sessions of a mobile station MS from the WLAN radio access network W1 to the 3GPP radio access network RAN (described with reference to
The first embodiment of the method of the invention is described next with reference to
This first embodiment relates to a situation in which the mobile station MS has already set up two communication sessions with the first and second service networks RS1 and RS2 via tunnels established between it and the GGSN nodes G1 and G2 (respectively connected to the first and second service networks RS1 and RS2) via the tunnel termination gateways T1 and T2. In this situation, a first access point name APN1 has been assigned to a first pair comprising the first tunnel termination gateway T1 and the first GGSN node G1 and a second access point name APN2 has been assigned to a second pair comprising the second tunnel termination gateway T2 and the second GGSN node G2.
The procedure for setting up an initial communication session via the WLAN radio access network W1 is well known to the person skilled in the art. For this reason it is not described in detail here. Suffice to say that a mobile station MS can be connected to the WLAN radio access network W1 via an access point AP. An access point AP is connected to the core network CRD either by at least one router of its WLAN network and tunnel termination gateways T1 and T2 via an interface called the Wp interface or directly to tunnel termination gateways T1 and T2 via the Wp interface if those tunnel termination gateways also implement the router function. Each tunnel termination gateway T1, T2 is connected, via an interface called the Gn′ interface, to a GGSN node G1, G2 that serves as an access point, via an interface called the Gi interface, to one or more packet-switched (PS) services offered by at least an application server of a service network RS1, RS2, for example. Each tunnel termination gateway T1, T2 has at least one communication identifier, for example an IP address, and where applicable an ISDN number (identifier).
When a communication session must be set up for a mobile station MS and for a given service, the station must first find the communication identifier (for example the IP address) of a tunnel termination gateway T1 or T2. For example, the mobile station MS can effect a domain name system (DNS) request for this purpose (arrow F1 in
Via an interface called the Gr′ interface, the tunnel termination gateway T1 or T2 sends a communication identifier of the mobile station MS and at least its own IP address, and generally its own ISDN number (identifier) to a home location register (HLR) of the core network CRD in order for it to store them in corresponding relationship to each other.
When the mobile station MS is getting ready to quit the WLAN radio access network W1 to be connected to the 3GPP radio access network RAN (arrow F0 in
As previously indicated, it is precisely at this stage that the method of the invention becomes operative.
In this first embodiment of the method of the invention, an SGSN node NS, connected via an interface called the Gn interface to the GGSN nodes G1 and G2, must take over from the tunnel termination gateways T1 and T2 involved up to this point in the two sessions of the mobile station MS.
In the case of a UMTS network, the 3GPP radio access network RAN comprises base stations known as Node Bs and radio network controllers (RNC). An RNC is generally connected to at least one Node B and to the 3GPP core network CRD by one of its SGSN nodes NS via an interface called the lu-PS interface. Each SGSN node NS has at least one communication identifier, for example an IP address, and possibly an ISDN number (identifier), and is connected to at least one GGSN node of the 3GPP core network CRD via a tunnel, preferably of the GPRS Tunneling Protocol (GTP) type, which uses an interface called the Gn interface.
When (in sessions) the mobile station MS quits the radio coverage area of the WLAN access network W1 and enters the radio coverage area of the 3GPP radio access network RAN, it sets up a UMTS connection to the SGSN node NS that is connected to the GGSN nodes G1 and G2 that provide access to the services that are the subjects of the sessions, via a Node B and the associated RNC (arrow F6 in
When the SGSN node NS receives the routing area update report, it must determine the transfer SGSN contexts (subjects of the sessions to be transferred) used by the mobile station MS in order to be substituted for the tunnel terminal gateways T1 and T2. For this purpose, it generates a message requesting the transfer SGSN contexts and then sends that message (arrow F8 in
Each transfer SGSN context that must be recovered contains a service PDP context and security elements specific to the mobile station MS concerned. A service PDP (Packet Data Protocol) context represents the definition of a current service. It includes the IP address of the GGSN node G1, G2 that serves as an access point to the service concerned, and where applicable the ISDN number (identifier) of said GGSN node G1, G2.
Moreover, the message requesting the transfer SGSN contexts is of the “SGSN context Request( )” type, for example.
The interface equipment ED is a new item of network equipment proposed by the invention. It is connected, firstly, to the SGSN node NS, for example via an interface called the Gn interface, secondly, to each tunnel termination gateway T1, T2, for example via another Gn interface, and, thirdly, to an AAA (Authentication, Authorization and Accounting) server SA of the core network CRD, for example via an interface called the Wm interface.
This interface equipment ED can, for example, constitute a proxy tunnel termination gateway TTG, i.e. a gateway supporting a subset of the functions supported by a standard tunnel termination gateway T1, T2. More precisely, the interface equipment ED is responsible i) for receiving requests to obtain SGSN contexts, ii) for identifying either tunnel termination gateways TTG by means of the AAA type server SA or an SGSN node by means of the home location register HLR, until this point connected to a mobile station MS, and iii) for requesting the corresponding SGSN contexts in order to send them to the elements that have requested them, namely new tunnel termination gateways TTG or a new SGSN node. Just like the terminal termination gateways T1 and T2, the interface equipment ED has at least one communication identifier, for example an IP address, and where applicable an ISDN number (identifier). It will be noted that the interface equipment ED can be installed in the AAA server SA.
It will be noted that a core network can include more than one interface equipment ED according to the invention, for example for security and/or load distribution reasons.
The transfer SGSN contexts are recovered in two phases: a first in which the interface equipment ED must recover at least one communication identifier of each tunnel termination gateway T1, T2 to which the transfer relates, and a second in which the interface equipment ED must recover the transfer SGSN contexts from the tunnel termination gateways T1 and T2 that it has identified.
The interface equipment ED includes, for example, a processor module MT responsible for recovering from the AAA server the communication identifiers of the tunnel termination gateways T1 and T2. Consequently, when the interface equipment ED receives from the SGSN node NS a message of the “SGSN Context Request( )” type, for example, its processor module MT generates a request, for example of the “TTG Location Request( )” type, containing the information necessary for recovering the communication identifiers of the tunnel termination gateways TTG (here T1 and T2) that are involved in the sessions of the mobile station MS. The interface equipment ED sends this message to the AAA server SA via the interface Wm (arrow F9 in
When the AAA server SA receives the “TTG Location Request( )” type message, for example, it searches its memory or database for the communication identifiers, for example the IP addresses, of the tunnel termination gateways TTG enabling execution of the sessions being transferred from the mobile station MS. The AAA server SA then generates a response message containing those communication identifiers and sends it to the interface equipment ED, via the interface Wm (arrow F10 in
On receiving the communication identifiers, the processor module MT generates a new message requesting the (first) transfer SGSN context of the first session (associated with APN1) of the mobile station MS that requested the transfer. This message (requesting the first transfer SGSN context) is of the “SGSN Context Request( )” type, for example. The interface equipment ED then sends this “SGSN Context Request( )” type message, for example, to the first tunnel termination gateway T1 identified in the response message received, via the interface Gn (arrow F11 in
In response to the received message, the first tunnel termination gateway T1 generates a response message containing the required first transfer SGSN context and sends it to the interface equipment ED, via the interface Gn (arrow F12 in
On receiving this first transfer SGSN context, the processor module MT generates a new message requesting the (second) transfer SGSN context of the second session (associated with APN2) from the mobile station MS that requested the transfer. This message (requesting the second transfer SGSN context) is of the “SGSN context Request( )” type, for example. The interface equipment ED then sends this “SGSN context request( )” type message, for example, to the second tunnel termination gateway T2 identified in the response message received, via the interface Gn (arrow F13 in
In response to the received message, the second tunnel termination gateway T2 generates a response message containing the required second transfer SGSN context and sends it to the interface equipment ED via the interface Gn (arrow F14 in
Once in possession of the two transfer SGSN contexts, the processor module MT inserts them into a response message that is sent to the SGSN node NS via the Gn interface (arrow F15 in
When the SGSN node NS receives the response message, it can effect security operations with respect to the mobile station MS and the home location register HLR before updating the service PDP contexts (arrows F16 and F17 in
Once these security operations, if any, have been effected, the SGSN node NS updates the service PDP contexts in order to eliminate and/or modify the end-to-end tunnels (of VPN/IPSec and GTP type) established between the mobile station MS and the GGSN nodes G1 and G2, via the tunnel termination gateways T1 and T2 (arrows (F2 and F3) and (F4 and F5) in
For this purpose, it generates a first service PDP context update request, for example. This first request is of the “Update PDP Context Request( )” type, for example. It is intended to inform the first GGSN node G1 that the SGSN node NS is being substituted for the first tunnel termination gateway T1 for the first service session of the mobile station MS. It consequently includes the communication identifier(s) of the SGSN node NS, the identifier of the mobile station MS, and other information linked to the latter. The SGSN node NS sends the first request to the first GGSN node G1 identified by the received first transfer SGSN context via the interface Gn (arrow F18 in
On receipt of this first request, the first GGSN node G1 stores the information that it contains and then sends the SGSN node NS a first acknowledgement message (arrow F19 in
On receipt of this first acknowledgement message, the SGSN node NS generates a second service PDP context update request, for example. The second request is of the “Update PDP Context Request( )” type, for example. It is intended to inform the second GGSN node G2 that the SGSN node NS is being substituted for the second tunnel termination gateway T2 for the second service session of the mobile station MS. It consequently includes the communication identifier(s) of the SGSN node NS, the identifier of the mobile station MS, and other information linked to the latter. The SGSN node NS sends the second request to the second GGSN node G2 identified by the received second transfer SGSN context via the interface Gn (arrow F20 in
On receipt of this second request, the second GGSN node G2 stores the information that it contains and then sends the SGSN node NS a second acknowledgement message (arrow F21 in
Once the SGSN node NS has received the two acknowledgement messages, it must update the home location register HLR. For this purpose, it generates a message to report the substitution of the access points of the mobile station MS for the sessions being transferred, for example. This message is of the “Update Location( )” type, for example. It consequently includes the communication identifier(s) of the SGSN node NS and the identifier of the mobile station MS. The SGSN node NS sends the message to the home location register HLR via the interface Gr (arrow F22 in
On receipt of this message, the home location register HLR updates its memory or database with the information that it contains and then sends the AAA server SA a message requesting elimination of the end-to-end (VPN/IPSec) tunnels established between the mobile station MS and the tunnel termination gateways T1 and T2 via an interface D′/Gr′ (arrow F23 in
On receipt of this message, the AAA server SA updates its memory or database with the information that it contains and then sends the first tunnel termination gateway T1 identified in said message, via the interface Wm (arrow F24 in
On receipt of this first request, the first tunnel termination gateway T1 eliminates the identified VPN/IPSec tunnel and then sends the AAA server SA a first acknowledgement message via the interface Wm (arrow F25 in
On receipt of this first acknowledgement message, the AAA server SA sends the second tunnel termination gateway T2 identified in said message, via the interface Wm (arrow F26 in
On receipt of this second request, the second tunnel termination gateway T2 eliminates the identified VPN/IPSec tunnel and then sends the AAA server SA a second acknowledgement message via the interface Wm (arrow F27 in
Once the AAA server SA has received the two acknowledgement messages, it sends the home location register HLR an acknowledgement message via the interface Wm (arrow F28 in
On receipt of this acknowledgement message, the home location register HLR sends the SGSN node NS an acknowledgement message via the interface Gr (arrow F29 in
On receipt of this acknowledgement message, the SGSN node NS sends the mobile station MS (which requested the transfer) a routing area update acceptance message via the interface lu-PS (arrow F30 in
On receipt of this message, the mobile station MS then establishes two new tunnels between itself and the SGSN node NS (arrows F31 and F33 in
Thanks to these new tunnels (arrows F31 to F34), continuity of service is assured for the mobile station MS during transfer of its communication sessions from the WLAN network to the 3GPP mobile network.
The second embodiment of the method of the invention is described next with reference to
The second embodiment relates to a situation in which the mobile station MS has already set up two communication sessions with the first service network RS1 and the second service network RS2 via tunnels established between it and the GGSN nodes G1 and G2 (connected to the first service network RS1 and the second service network RS2, respectively), via the SGSN node NS (arrows F1′ to F5′ in
The procedure for setting up an initial communication session via the 3GPP radio access network RAN is well known to the person skilled in the art. It is therefore not described in detail here. Suffice to say that a mobile station MS can be connected to the 3GPP radio access network RAN via one of its base stations (Node B). Such a Node B is connected to a radio network controller (RNC) that is also part of the 3GPP radio access network RAN. The RNC is connected to the 3GPP core network CRD by one of its SGSN nodes NS via the lu-PS interface. This SGSN node NS has at least one communication identifier, for example an IP address, and generally an ISDN number (identifier), and is connected, via a tunnel that is preferably a GTP tunnel, using an interface called the Gn interface, to at least one of the GGSN nodes G1, G2.
When a communication session must be set up for a mobile station MS and for a given service, the station must first find a communication identifier of the SGSN node NS that is connected to the GGSN node that provides access to the service to which the session relates. The mobile station MS then sends its tunnel establishment request to the SGSN node concerned. Once the tunnels have been established, the SGSN node NS sends the home location register HLR, via an interface called the Gr interface, an identifier of the mobile station MS and at least its own IP address and generally its own ISDN number (identifier), in order for it to store them in corresponding relationship to each other.
When the mobile station MS is getting ready to quit the 3GPP radio access network RAN to be connected to a WLAN radio access network W1 (arrow F0′ in
As previously indicated, it is precisely at this stage that the method of the invention becomes operative.
In this second embodiment of the method of the invention, the tunnel termination gateways T1 and T2 connected to the GGSN nodes G1 and G2 via the interface Gn must take over from the SGSN node NS that until this point was involved in the two sessions of the mobile station MS.
When (in sessions) the mobile station MS quits the radio coverage area of the 3GPP radio access network RAN and enters the radio coverage area of the WLAN radio access network W1, it sets up a WLAN connection to the WLAN network (arrow F6′ in
When the first tunnel termination gateway T1 receives the tunnel establishment request, it must first generate for sending to the AAA server (arrow F8′ in
On receipt of this request, the AAA server SA generates for sending to the first tunnel termination gateway T1 that has interrogated it (arrow F9′ in
On receipt of this response message, the first tunnel termination gateway T1 can start an EAP authentication and authorization procedure for the first session associated with the first access point name APN1, on the one hand with the mobile station MS (arrow F10′ in
Once the EAP procedure has terminated, the first tunnel termination gateway T1 must determine the transfer SGSN contexts (that are the subjects of the sessions to be transferred) used by the mobile station MS in order for it to be substituted for the SGSN node NS involved in the transfer of the sessions. For this purpose, it generates a message requesting the transfer SGSN contexts and then sends that message (arrow F12′ in
This message requesting the transfer SGSN contexts is of the “SGSN Context Request( )” type, for example.
On receipt of this request message, the interface equipment ED generates for sending to the home location register HLR (arrow F13′ in
On receipt of this request, the home location register HLR recovers from its memory or database the communication identifier(s) (for example the IP address) of the SGSN node NS that is involved in the open sessions of the mobile station MS. It then generates for sending to the interface equipment ED (arrow F14′ in
On receipt of this response message, the processor module MT of the interface equipment ED must recover the transfer SGSN contexts from the SGSN node NS. For this purpose, it generates a message requesting the transfer SGSN contexts of the sessions of the mobile station MS that requested the transfer. This message is also of the “SGSN Context Request( )” type, for example. The interface equipment ED sends this SGSN Context Request( ) type message, for example, via the interface Gn (arrow F15′ in
In response to this received message, the SGSN node NS generates a response message containing the requested first and second transfer SGSN contexts and sends it to the interface equipment ED via the interface Gn (arrows F16′ in
On receipt of these transfer SGSN contexts, the processor module MT generates a response message containing said transfer SGSN contexts. The interface equipment ED then sends this response message to the first tunnel termination gateway T1 that originated the session transfer and that it has previously made responsible for recovering the contexts, via the interface Gn (arrows F17′ in
When the first tunnel termination gateway T1 receives the response message, it begins updating the service PDP contexts intended to eliminate and/or modify the end-to-end tunnels (of VPN/IPSec and GTP types) established between the mobile station MS and the GGSN nodes G1 and G2, via the SGSN node NS (arrows (F2′ and F3′) and (F4′ and F5′) in
For this purpose, it generates a first service PDP context update request, for example. This first request is of the “Update PDP Context Request( )” type, for example. It is intended to inform the first GGSN node G1 that the first tunnel termination gateway T1 is being substituted for the SGSN node NS for the first service session of the mobile station MS. It consequently includes the communication identifier(s) of the first tunnel termination gateway T1, the identifier of the mobile station MS and other information linked to the latter. The first tunnel termination gateway T1 sends the first request to the first GGSN node G1 identified by the first received transfer SGSN context, via an interface called the Gn′ interface (arrow F18′ in
On receipt of this first request, the first GGSN node G1 stores the information that it contains and then sends the first tunnel termination gateway T1 a first acknowledgement message that constitutes a substitution confirmation message (arrow F19′ in
On receipt of this first acknowledgement message, the first tunnel termination gateway T1 sends an acknowledgement message to the interface equipment ED (arrow F20′ in
The first tunnel termination gateway T1 then sends the AAA server (arrow F21′ in
The processor module MT of the interface equipment ED then generates a message containing the second transfer SGSN context. The interface equipment ED then sends this message via the interface Gn (arrow F22′ in
On receipt of this message, the second tunnel termination gateway T2 can start an EAP procedure for the second session associated with the second access point name APN2, on the one hand with the mobile station MS (arrow F23′ in
Once the EAP procedure has terminated, the second tunnel termination gateway T2 generates a second service PDP context update request, for example. The second request is of the “Update PDP Context Request( )” type, for example. It is intended to inform the second GGSN node G2 that the second tunnel termination gateway T2 is being substituted for the SGSN node NS for the second service session of the mobile station MS. It consequently includes the communication identifier(s) of the second tunnel termination gateway T2, the identifier of the mobile station MS and other information linked to the latter. The second tunnel termination gateway T2 sends the second request to the second GGSN node G2, identified by the received second transfer SGSN context, via the interface Gn′ (arrow F25′ in
On receipt of this second request, the second GGSN node G2 stores the information that it contains and then sends the second tunnel termination gateway T2 a second acknowledgement message that constitutes a substitution confirmation message (arrow F26′ in
On receipt of this second acknowledgement message, the second tunnel termination gateway T2 can send an acknowledgement message to the interface equipment ED (arrow F27′ in
The second tunnel termination gateway T2 then sends the AAA server (arrow F28′ in
On receipt of this message, the home location register HLR updates its memory or database with the information that it contains and then sends the SGSN node NS a message requesting elimination of the end-to-end tunnels established between it and the mobile station MS, via the interface Gr (arrow F30′ in
On receipt of this message, the SGSN node NS eliminates the tunnels established with the identified mobile station MS and then sends the home location register HLR, via the interface Gr (arrow F31′ in
On receipt of this acknowledgement message, the home location register HLR sends the AAA server SA, via the interface D′/Gr′ (arrow F32′ in
On receipt of this message the AAA server SA updates its memory or database, and then sends the first tunnel termination gateway T1 that originated the transfer, via the interface Wm (arrow F33′ in
On receipt of this acknowledgement message the first tunnel termination gateway T1 sends the mobile station MS (which requested the transfer) an end of procedure report message, via the interface lu-PS (arrow F34′ in
On receipt of this message, the mobile station MS can then use the two new (VPN/IPSec) tunnels established between it and the tunnel termination gateways T1 and T2 (arrows F35′ and F37′ in
Thanks to these new tunnels (arrows F35′ to F38′), continuity of service is therefore assured for the mobile station MS during the transfer of its communication sessions from the 3GPP mobile network to the WLAN network.
The processor module MT of the interface equipment ED can be produced in the form of electronic circuits, software (or electronic data processing) modules, or a combination of circuits and software.
The invention is particularly advantageous because it requires neither modification or adaptation of the SGSN nodes and the GGSN nodes already installed in the 3GPP core network, nor the creation of new protocols. Furthermore, the invention enables the use of the standard 3GPP interfaces.
The invention is not limited to the interface equipment ED and management method embodiments described hereinabove by way of example only, but encompasses all variants that the person skilled in the art might envisage within the scope of the following claims.
Number | Date | Country | Kind |
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0653324 | Aug 2006 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2007/058282 | 8/9/2007 | WO | 00 | 2/2/2009 |