Wireless access gateway

A wireless network including a wireless access gateway (WAG) and methods are provided for routing traffic between non-cellular and cellular networks. The WAG interconnects at least one non-cellular network and at least one cellular network in an at least one-to-many relationship. The WAG receives a first IP address for the UE in the cellular domain and the WAG allocates a second IP address for the UE in the non-cellular domain. The WAG creates a routing rule including the first and second IP addresses for the UE and an additional data path identifier.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a National Phase entry of PCT Application No. PCT/GB2015/050515, filed on 24 Feb. 2015, which claims priority to EP Patent Application No. 14250039.6, filed on 12 Mar. 2014, which are hereby fully incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a wireless network including a wireless access gateway and a method for controlling traffic roaming between cellular and non-cellular networks.

BACKGROUND

In recent years, it has become increasingly desirable for Mobile Network Operators (MNOs) to integrate their cellular and non-cellular (e.g. Wi-Fi) networks. This provides a mechanism for the MNO to both offload cellular data traffic onto a Wi-Fi network having a wired data connection (which is generally more suited to high data demands) and “onload” traffic seamlessly back onto the cellular network. Accordingly, modern cellular technologies, such as the 3rdGeneration Partnership Project (3GPP) LTE networks, have evolved to include a tight integration between the cellular and non-cellular networks, such that handovers between the two networks are correctly authenticated and maintain consistent policy and charging control.

4G network standards provide a framework for interconnecting the non-cellular (commonly known as “non-3GPP”) network and the Evolved Packet Core, EPC, through the trusted and untrusted access specification (as specified in 3GPP Technical Specification 23.402 Release 12 Architectural Enhancements for Non-3GPP Access). The standards do not strictly define when a non-3GPP network is trusted or not (this is at the discretion of the MNO), but they do define how the MNO must treat the traffic—the principle difference being that untrusted non-3GPP connections must include an IPSec tunnel between the User Equipment, UE, and the EPC. For trusted networks, communication between the UE and EPC is considered secure (e.g. by using SIM based authentication with the UE and WPA2 IEEE 802.11i-2004 security in the Wi-Fi Access network).

Most of today's networks (e.g. 2G and 3G networks) predate the 4G standards. However, it is still desirable for MNOs to integrate the non-3GPP and pre-4G cellular networks. To make this possible, a Wireless Access Gateway (WAG) is used to interconnect the two networks. The WAG connects to the cellular network using the GPRS Tunneling Protocol, GTP, connecting directly to a Gateway GPRS Support Node, GGSN. However, the data connection between the WAG and the non-3GPP network is not standardized. Accordingly, a variety of methods for routing user plane data from a non-3GPP network to the cellular network have been used. These existing methods can be grouped into Layer 2 or Layer 3 integration. Layer 2 integration can be complicated to implement, requiring the WAG to become part of the Wireless Access Network. This increases the cost of deployment for a Wi-Fi Network operator. Thus, the distributed architecture of Layer 3 integration (in which the WAG is a separate component in the network) is more desirable.

In Layer 3 integration, the user plane IP traffic is routed from the Wi-Fi Network's Wireless LAN Controller (WLC) to the WAG, and then from the WAG to the cellular network. The key issue with the Layer 3 approach is associating the IP address for the UE in the non-3GPP network with the IP address for the UE in the cellular network. There are several techniques, including the following two examples. Firstly, the ‘Radius Framed-IP-Address’ technique involves the AP allocating an IP address for a User Equipment, UE, and subsequently informing the WAG of this IP address using the RADIUS signaling message. Secondly, the ‘DHCP Relay’ technique involves the DHCP request message issued by the WAG being ‘relayed’ to the WAG, and the WAG issuing the IP address for the UE. The WAG may then set up the appropriate routing rules with the IP address in the cellular network.

The Cisco enhanced Wireless Access Gateway (eWAG) is an example of a Layer 3 integration of the WAG. An example of the eWAG can be found at the following URL: http://www.cisco.com/assets/global/YU/expo2012/pdfs/sp_wifi_sesija_1_core.pdf. In the Cisco system, an Access Point allocates the IP address in the Wi-Fi domain for the UE, and supplies this IP address to the eWAG as part of the Framed-IP-Address element of the RADIUS Accounting Start message. The MNO supplies the IP address in the cellular domain, and the eWAG sets up the appropriate routing rules.

The present inventors have identified several problems with the existing techniques. Firstly, the 3GPP standards specify that the MNO must allocate the IP address for the UE, which is then routed to the corresponding IP address for the UE in the non-3GPP domain by the WAG. However, if the WAG is connected to multiple MNOs, the MNOs may issue the same IP address for the same UE. This creates an issue when the WAG routes IP traffic from the UE to the cellular network, as it cannot differentiate between the two MNOs for that IP address. Secondly, the IP address issued to the UE in the non-3GPP domain may conflict with an IP address for another UE connected to the AP. This may happen, for example, when the IP address in the non-3GPP domain is issued by the WAG. This IP address conflict will create an issue when the WAG routes IP traffic to the UE in the non-3GPP domain, as the same IP address is associated with two UEs.

Furthermore, the prior art techniques provide a method of setting up a data path between the UE and cellular data network, but this data path must be torn down if the UE roams out of the non-3GPP network (e.g. onto a distinct non-3GPP network). Thus, IP address sensitive applications cannot continue to function when the UE roams between non-3GPP networks.

It is therefore desirable to alleviate some or all of the above problems.

SUMMARY

According to a first aspect of the disclosure, there is provided a method of controlling a wireless access gateway (WAG) the WAG interconnecting at least one non-cellular network and at least one cellular network in an at least one-to-many relationship, the method comprising: a WAG receiving a first IP address for a User Equipment (UE) from a first cellular network; the WAG allocating a second IP address for the UE and sending the second IP address to a first non-cellular network; and the WAG defining a routing rule including the first and second IP addresses for the UE and a data path identifier.

Thus, in a scenario in which a WAG interconnects several cellular networks to one non-cellular network and the several cellular networks allocate the same IP address to different UEs, the WAG may use the data path identifier to distinguish between the different data paths. This allows the WAG to be used as a gateway between networks owned by several distinct operators.

The data path identifier may be a first cellular network identifier. The data path identifier may also be a UE IMSI, GTP tunnel endpoint IDs or any other unique UE identifier.

The method may further comprise the WAG receiving a GPRS Tunneling Protocol (GTP) request message from the first non-cellular network before the step of the WAG receiving a first IP address for the UE. The method may also comprise the step of establishing a GTP tunnel between the WAG and the first non-cellular network. Accordingly, the WAG may establish GTP tunnels between the WAG and the non-cellular network and between the WAG and cellular networks. The WAG may therefore be compatible with GTP enabled Wi-Fi equipment.

The method may further comprise, initially, the WAG sending an authentication message for the UE to the first cellular network; and the WAG receiving an authentication vector for the UE from the first cellular network. The WAG may receive a plurality of authentication vectors (for example, up to five authentication vectors), which may be stored in memory.

The WAG may allocate the second IP address for the UE from a dedicated pool of IP addresses for the first non-cellular network. Thus, the non-3GPP network (e.g. a Wi-Fi network) may define a first range of IP addresses to be used for roaming devices and a second range of IP addresses to be used for non-roaming devices, and the WAG may use the first range as the pool of IP addresses dedicated to the non-3GPP network. Accordingly, the WAG can allocate an IP address which will not conflict with a non-roaming device. The WAG may then define a routing rule including the first and second IP addresses for the UE and subsequently route traffic according to this rule.

The WAG may interconnect a plurality of non-cellular networks to a cellular network, and the method may further comprise: the WAG allocating a third IP address for the UE, the third IP address allocated from an IP address range dedicated to a second non-cellular network; the WAG sending the third IP address to the second non-cellular network; and the WAG updating the routing rule to indicate the first and third IP addresses for the UE. Accordingly, in a scenario in which a UE roams between two non-cellular networks, the WAG may act as a mobility anchor. That is, the WAG may maintain the GTP tunnel with the cellular network whilst a new IP address is issued for the UE in the new non-cellular network and the routing rule may be updated to reflect the new data path. Any IP address sensitive applications on the UE may therefore continue to operate whilst the UE roams between the two non-cellular networks.

The WAG may use a stored authentication vector for the UE to authenticate the UE. Thus, the WAG does not need to exchange authentication messages with the cellular network when the UE roams between the two non-cellular networks.

A computer program is provided containing computer-executable code which, when executed on a computer, causes the computer to perform the method of the first aspect of the disclosure.

According to a second aspect of the disclosure, there is provided a device adapted to interconnect at least one non-cellular network and at least one cellular network in an at least one-to-many relationship, the device comprising a communications interface adapted to receive a first IP address for a User Equipment (UE) from a first cellular network; and a processor adapted to allocate a second IP address for the UE, wherein the communications interface is further adapted to send the second IP address to the first non-cellular network, and the processor is further adapted to create a routing rule including the first and second IP addresses for the UE and an additional data path identifier.

The communications interface may be further adapted to receive a GPRS Tunneling Protocol (GTP) request message from the first non-cellular network, and the processor may be further adapted to establish a GTP tunnel with the first non-cellular network.

The communications interface may be further adapted to send an authentication message for the UE to the first cellular network and to receive an authentication vector for the UE from the first cellular network.

The processor may be adapted to allocate the first IP address for the UE from an IP address range dedicated to the first non-cellular network.

The device may be adapted to interconnect a plurality of non-cellular networks to a cellular network, wherein the processor may be further adapted to allocate a third IP address for the UE, the third IP address allocated from an IP address range dedicated to a second non-cellular network, the communications interface may be further adapted to send the third IP address to the second non-cellular network, and the processor may be further adapted to update the routing rule to include the first and third IP addresses for the UE. The communications interface may use the stored authentication vector for the UE to authenticate the UE.

The device may further comprise a NAT, wherein the processor may be further adapted to update the NAT with the routing and translation rule and the NAT may be adapted to route and translate traffic according to the routing and translation rules.

A wireless network including the device is also provided. The device may be a dedicated Wireless Access Gateway or may be integrated into another element in the wireless network.

DETAILED DESCRIPTION OF EMBODIMENTS

A first embodiment of the present disclosure will now be described with reference toFIGS. 1 and 3.FIG. 1illustrates a wireless network1including a Wireless Access Gateway (WAG)10, a first Wi-Fi operator20, first and second Mobile Network Operators (MNOs)30,40, and a first and second UE50,60. The WAG10interconnects the first Wi-Fi operator20and the first and second MNOs30,40.

The WAG10includes an Authentication, Authorization and Accounting, AAA, proxy server11, a DCHP server13and a GPRS Gateway (GTP GW)15(including a Network Address Translation, NAT, module17). The WAG10also includes a first communications interface adapted to communicate with the Wi-Fi operator20, and a second communications interface adapted to communicate with the first and/or second MNO30,40.

The first Wi-Fi operator20includes an Access Point21and an Authentication, Authorization and Accounting, AAA, server23. The Access Point21includes an antenna adapted to communicate with the first and second UE and a Wireless LAN controller (WLC). The Access Point21also has a fixed data connection (such as a DSL data connection), which may be used to communicate with the WAG10.

The first and second MNO30,40also include first and second DHCP servers31,41, first and second Home Subscriber Services, HSS33,43, and first and second Packet Data Network Gateways (PGWs)35,45. The first and second PDWs35,45connect the MNOs30,40to a first and second Pack Data Network (PDN)70,80, such as the Internet. The first and second MNOs30,40also include first and second communications interfaces respectively, adapted to communicate with the WAG10.

The first UE50is associated with the first MNO30and has roamed onto the first Wi-Fi operator's20network. The second UE60is associated with the second MNO40and has also roamed onto the first Wi-Fi operator's20network. The WAG10is configured to set up a first and second data path, between the first UE and first MNO and between the second UE and the second MNO, respectively. This may be implemented by a method of the first embodiment, which will now be described in more detail with reference toFIGS. 2 and 3.

FIG. 2is a diagram illustrating the message flow for the setup of a data path between the first UE50and the first MNO30, andFIG. 3is a corresponding flow chart. On reviewing the following description, the skilled person will understand that the method applies to the setup of a data path between any UE and any MNO connected to the WAG10, in a manner that alleviates the IP address issues of the prior art.

As a first task (S1), the first UE50roams onto the Wi-Fi operator's20network and attempts to connect to the Access Point21. Accordingly, the first UE50sends an ‘EAP start’ message to the Access Point21, to initiate SIM based authentication using an Extensible Authentication Protocol, EAP. The Access Point/Wireless LAN Controller21delivers the EAP start message to the Wi-Fi operator's20AAA server23(e.g. via its DSL connection).

In response to receiving the EAP start message, the Wi-Fi operator's20AAA server23exchanges authentication messages with the AAA proxy server11in the WAG10(S2). This exchange may use the RADIUS or DIAMETER protocols. In S3, the WAG10exchanges authentication messages with the first MNO's30HSS33(using SS7 MAP, RADIUS or DIAMETER protocols), and, in this embodiment, receives an address for the PGW35of the first MNO.

On successful authentication with the first MNO, the Wi-Fi operator's20AAA server23sends an ‘EAP Success’ message to the first UE50via the Access Point21(S4).

The first UE50then requests an IP address. In this embodiment, it sends a ‘DHCP Discover’ message to the Access Point21, including the MAC address of the first UE50(S5). On receipt of this DHCP message50, the first Wi-Fi operator's WLC initiates a first GTP (GPRS Tunneling Protocol) creation request message, which is sent to the GTP GW15in the WAG10(S6). The skilled person will understand that the GTP tunnel creation request message will be a CreateSessionRequest in GTPv2 or CreatePDPContext in GTPv1.

The GTP creation request message includes the International Mobile Subscriber Identity (IMSI) of the user. The WLC retrieves the IMSI from the EAP authentication messages by linking them to the UE's MAC address (in the DHCP Discover message).

In S7, the GTP GW15receives the first GTP creation request message, and sends a second GTP creation request message to the first MNO's PGW35(using the address obtained during the exchange of authentication messages).

The PGW35allocates a first IP address IPM11 for the first UE (S8). This IP address is allocated from an IP address pool (e.g. IPM1(1 . . . n)), by a DHCP exchange with the first MNO's30DHCP server31. The PGW35then responds to the GTP tunnel creation request by sending the first UE's50first IP address to the GTP GW15(S9). A first GTP tunnel is thus established between the WAG10and first MNO's30PGW35(S10), using the tunnel endpoint identifiers.

The GTP GW15then requests a second IP address IPw11 for the first UE50on behalf of the first Wi-Fi operator20(S11). The second IP address is allocated from an IP address pool (e.g. IPw1(1 . . . n)) which, in this embodiment, is dedicated to the first Wi-Fi operator20, by a DHCP exchange with the WAG's10DCHP server13. The GTP GW15is preconfigured with the dedicated IP address pool, which has been sent to the GTP GW15by the first Wi-Fi operator20. The first Wi-Fi operator20may therefore define an IP address pool which does not conflict with a range of IP addresses reserved for other UEs on its network (e.g. non-roaming UEs).

The GTP GW15then responds to the GTP tunnel create request message (sent by the WLC in S6) by sending the first UE's50second IP address IPw11 to the first Wi-Fi operator's20WLC (step S12). A second GTP tunnel is thus established between the WAG10and the first Wi-Fi operator's20WLC (S13), and the WAG10sets up the appropriate routing and translation rules between the two tunnel endpoints (S14).

The routing rule also includes a further identifier for the data path between the UE50and first MNO30, which, in this embodiment, is an MNO identifier. Accordingly, in a scenario in which the same IP address is allocated to several UEs by several network operators on one side of the WAG (e.g. several MNOs), but different IP addresses on the other side of the WAG, the WAG may use this further identifier to distinguish between the two data paths.

The first Wi-Fi operator's20WLC may then respond to the DHCP Discover message from the UE (from S5), by sending a DHCP Offer/Request/Acknowledge message, including the second IP address IPw11 (S15).

FIG. 1illustrates a data path between the first UE50and PDW35(which is connected on to the first PDN70) created by the method as described above. In this example, the first IP address IPM11 is 10.21.3.45 and the second IP address IPW11 is 192.168.5.23. The WAG10therefore creates a routing and translation rule for the first UE50, including its first IP address (i.e. on the Wi-Fi operator's network), its second IP address (i.e. on the first MNO's network) and a first MNO50identifier, e.g. IPw11⇔tuple (MNO1, IPm11). Accordingly, data traffic for the first UE50originating at either the first UE50or on the first MNO30may be routed successfully by the WAG10to its destination.

FIG. 1also illustrates the data path between the second UE60and PDW35(which is connected to the second PDN80), which may also be created using the method as described above. In this example, the second UE60is allocated IP address 192.168.5.24 in the Wi-Fi operator's20domain and IP address 10.21.3.45 in the second MNO's40domain. Accordingly, the WAG10creates a routing and translation rule for the second UE60, including its IP address on the Wi-Fi operator's network, its IP address on the second MNO's network and a second MNO60identifier, e.g. IPw22⇔tuple (MNO2, IPm21).

The skilled person will understand that there is potentially an IP address conflict in the example shown inFIG. 1. That is, both the first and second UE50,60have been allocated the same IP address by the first and second MNO, respectively. However, the WAG10may use the MNO identifiers to differentiate between the two UEs and perform the appropriate routing and address translations. The skilled person will understand that this differentiation may be made for data traffic in the opposing direction (e.g. several Wi-Fi operators allocating the same IP address to several UEs, and one MNO allocating different IP addresses to the UEs), by using the further data path identifier (e.g. the UE's IMSI, GTP tunnel endpoints, etc.).

The above embodiment illustrates how the present disclosure provides an improved WAG and method for controlling traffic between non-cellular and cellular networks. The IP address for the UE in the non-cellular domain is allocated from a pool of dedicated IP addresses. That is, the pool of IP addresses may be specified by the Wi-Fi operator, such that a specific range of IP addresses are reserved for roaming UEs. The Wi-Fi operator may therefore allocate IP addresses outside this range to other UEs on its network (i.e. non-roaming UEs). Accordingly, when a new UE roams onto the network and requests an IP address, the IP address may be allocated from the range reserved for roaming UEs such that there is no conflict with non-roaming UEs.

Furthermore, GTP tunnels are provided between both the WAG and the MNOs and the WAG and the Wi-Fi operator. The WAG may therefore be provided using a Layer 3 architecture, such that conventional Access Points may still be used to provide trusted non-3GPP access, and connect using the preferred GTP protocol (which is commonly used between entities in the 3GPP architecture).

Also, the additional data path identifier may be used to successfully route traffic over the WAG in a scenario in which the same IP address is allocated to several UEs by several network operators on one side of the WAG (e.g. several Wi-Fi operators or several MNOs), but different IP addresses on the other side of the WAG.

Embodiments of the present disclosure may also act as a mobility ‘anchor’ when a UE roams between two Wi-Fi operator networks, as illustrated in the following second embodiment.

FIG. 4illustrates a second embodiment of the present disclosure, showing a wireless network100including a wireless access gateway (WAG)110, first and second Wi-Fi operators120,130, a first MNO140, and a first UE150. Each element is similar to its counterpart in the first embodiment of the present disclosure (i.e. both the first and second Wi-Fi operators120,130are similar to the first Wi-Fi operator20of the first embodiment).

In this embodiment, the first UE50initially roams onto the first Wi-Fi operator's network120and a data path is set up between the first UE150and the first MNO140. Accordingly, the WAG110sets up routing and translation rules for the first UE150. Subsequently, the first UE150roams from the first Wi-Fi operator's120network to the second Wi-Fi operator's130network. In this embodiment, the WAG110is configured to maintain the session and IP address on the first MNO's network whilst the first UE150attaches to the second Wi-Fi network and is allocated a new IP address. This allows any IP address sensitive applications to continue despite the access network changing. Diagrams illustrating the setup and handover of the first UE150are shown inFIGS. 5 and 6.

The first fifteen tasks (S1to S15) ofFIG. 6are similar to those shown inFIG. 3and described in the accompanying description above. For simplicity, the reader should refer to the above description for more detail on these tasks.

At S16, the first UE150detaches from the first Wi-Fi operator's120network. In this embodiment, the WAG110receives a notification from the first Wi-Fi operator's120network that the first UE150has been disconnected (S17). The WAG110does not immediately tear down the GTP tunnel towards the first MNO140, but instead starts a timer.

The first UE150then attempts to connect to the Access Point131of the second Wi-Fi operator's network130(S18). Accordingly, the first UE150issues an EAP Start message to initiate SIM based authentication using EAP, which is delivered to the second Wi-Fi operator's130AAA server133(S19). The second Wi-Fi operator's130AAA server133then exchanges authentication messages (using RADIUS or DIAMETER protocols) with the AAA proxy server111in the WAG110(S20).

In this embodiment, the WAG110exchanges authentication messages with the first MNO's HSS using, for example, the SS7, RADIUS or DIAMETER protocols (S21). On successful authentication with the first MNO140, the second Wi-Fi operator's130AAA server133sends an EAP Success message to the first UE150(S22).

The first UE150then sends a DHCP Discover message to the second Wi-Fi operator's130Access Point131to request a new IP address (S23). On receipt of this DHCP discover message, the second Wi-Fi operator's130WLC sends a GTP tunnel creation request (either CreateSessionRequest in GTPv2 or CreatePDPContext in GTPv1) towards the GTP GW115of the WAG110(S24).

In the second embodiment, the GTP GW115receives the GTP tunnel creation request and recognizes that a GTP tunnel has already been established between the WAG110and first MNO140for the first UE150(in S10), and the GTP tunnel tear down timer is cleared (S25).

The GTP GW115then requests a new IP address IPw21 for the first UE150on behalf of the second Wi-Fi operator130(S26). The new IP address is allocated from an IP address pool (e.g. IPw2(1 . . . n)) dedicated to the second Wi-Fi operator130, by a DHCP exchange with the WAG's110DCHP server113. The GTP GW115then responds to the GTP tunnel create request message by sending the first UE's150second IP address IPw21 to the second Wi-Fi operator's130WLC (S27). A new GTP tunnel is thus established between the WAG110and the second Wi-Fi operator's130WLC (S28).

In S29, the GTP GW115updates the routing and translation rules between the two tunnel endpoints such that traffic will be routed between the new tunnel endpoints (i.e. from the second Wi-Fi operator140to the existing GTP tunnel towards the first MNO140). Thus, a new data path has been established for the first UE150between the second Wi-Fi operator140and the first MNO140, without losing the session on the first MNO domain. The WAG110therefore acts as a mobility anchor for a UE roaming between two non-cellular networks.

In S21of the second embodiment, the WAG exchanges authentication messages with the first MNO's HSS. However, in a further enhancement, such an exchange is not necessary. That is, the WAG110may receive a plurality of authentication vectors in S1to S4, and store one or more of these vectors in memory. The WAG110may use a stored authentication vector to authenticate the first UE150without forwarding messages on to the first MNO140. Thus, the first MNO140does not even need to be informed of the change of access network. The WAG110may include a memory to store a plurality of authentication vectors for a plurality of UEs.

In the above embodiments, the WAG initiates a GTP tunnel creation request towards the MNOs PDW. The skilled person will understand that the address of the PDW may be obtained during the authentication phase, or may be statically configured.

Furthermore, in both the first and second embodiments, the UE issues an EAP Start message to initiate SIM based authentication. This method is advantageous as it allows transparent and secure authentication with minimal interaction from the user. Whilst other forms of authentication are possible within the scope of the disclosure (e.g. IEEE 802.1X authentication or portal-based authentication), the EAP-based method above is the most convenient for the user and will therefore promote better utilization of non-3GPP networks and thus more data offloading.

To aid understanding of the disclosure, the description above specifies several protocols which may be used for the exchange of messages between the various elements of the wireless network. However, the skilled person will understand that these are non-essential, such that any appropriate protocol may be used.

Furthermore, whilst the embodiments above illustrate examples of a WAG connecting Wi-Fi operators to MNOs, the skilled person will understand that the WAG may interconnect any form of non-cellular network to any form of cellular network. The WAG may also interconnect any number of non-cellular networks to any number of cellular networks (such as in a one-to-one, one-to-many, or many-to-many relationship).

In the above embodiments, the WAG creates a routing rule mapping the first and second IP addresses and an MNO ID. The MNO ID is used to route traffic between the UE and MNO in a scenario in which several MNOs allocate the same IP address to different UEs. However, the skilled person will understand that any identifier for the data path may be used for this purpose, such as the UE IMSI, or GTP tunnel endpoint IDs.

The description illustrates an example in which the Wi-Fi operator defines a range of IP addresses for roaming devices and sends this to the WAG. The WAG may then allocate an IP address to the UE in the Wi-Fi domain from this range of IP addresses. However, the skilled person will understand that this method of determining the IP address range is just one example, and the WAG may determine the range of IP addresses by a variety of techniques. Furthermore, the task of allocating an IP address to the UE in the Wi-Fi domain from a dedicated range of IP addresses is non-essential. The range of IP addresses may be configured statically when setting up the WAG. Alternatively, the WAG may send a ‘DHCPInform’ message to a Wi-Fi network operator's network, which may return a subnet mask for non-roamed traffic. The range of IP addresses may be determined from this subnet mask.

Furthermore, the skilled person will understand that the WAG may set up the routing and translation rules in a variety of ways. For example, the WAG may include a NAT module, and the WAG may cause the routing and translation rules to be created in the NAT. Additionally or alternatively, the WAG may include a processor adapted to create the routing and translation rules and perform the routing and IP address translation itself (such as by an Application Level Gateway). The skilled person will also understand that the WAG may route the traffic, whilst another element may perform the translation.

The skilled person will understand that any combination of features is possible within the scope of the disclosure, as claimed.