GB2414629A - Charging for services provided to mobile terminals over a data communications network - Google Patents

Abstract

IP based communications are transmitted between terminals 1 and 3, via respective mobile networks 5, 5A and IMS networks 9, 9A, and via internet 23. Messages relating to a particular service are provided with a component that identifies the service and is interpretable by the internet 23. These service-identifying components allow the control of the message transmission relating to a particular service request, and also allow the mobile terminal to be charged on the basis of use of a particular service. A portion if this charge may be shared between networks within the internet 23 that carry the messages and which facilitate provision of the service.

Description

1 2414629 COMMUNICATIONS NES vvOKKS The present invention relates to a

method of and system for enabling a first device to use a service provided via a data communications network linking the first device to a second device, and also to a method of providing a service to a device registered with a first communications network, the service being provided via a second communications network.

According to a first aspect of the present invention, there is provided a method of enabling a first device to use a service provided via a data communications network linking the first device to a second device, the method including routing messages between the first device and the second device via the data communications network, wherein the messages include information indicative of the service to which they relate.

According to a second aspect of the present invention, there is provided a system for enabling a first device to use a service provided via a data communications network linking the first device to a second device, the system including means for routing messages between the first device and the second device via the data communications network, wherein the messages include infonnation indicative of the service to which they relate.

According to a third aspect of the present invention, a method of providing a service to a device registered with a first communications network, the service being provided via a second communications network, the method including generating a plurality of data packets for transmitting data relating to the service via said second communication network, each of said data packets including an element that identifies the particular r equest for service and is interpretable by the second communication network such that the second communication network can obtain payment from the first network forth transmitting the data packet in respect of that servlcc.

For a better understanding of the invention, a method and system embodying the invention will now be described by way of example, with reference to the accompanying drawings in which: Figure 1 shows schematically the elements of a communications system in accordance Title the present invention; and Figure 2 shows the transmission of data via a plurality of carriers.

When mobile or cellular telecommunication systems were initially launched communication between mobile devices was limited solely to voice communication.

This was later supplemented by the Short Message Service (SMS) and more recently Multimedia Messaging Service (MMS) technology and other data services, allowing users to send text, pictures and other data to other devices.

Data transmission is separate to a standard voice call - data are sent by connecting a mobile terminal to a server over a General Packet Radio Service (GPRS) data connection. Voice calls are transmitted conventionally by circuit switched connections, and GPRS data, of course, is transmitted by packet switched connections.

The third generation partnership project (3GPP) has recently defined a new concept known as IMS (IP - based Multimedia Subsystem). The TMS is a set of core network servers sitting behind the GGSN (which will be briefly described below) in the packet switched domain. These servers are introduced in order to process signalling between end users. The aim of IMS is to allow users such as mobile telephone network operators to provide services to their subscribers as efficiently and effectively as possible. For example, the IMS architecture is likely to support the following communication types: voice, video, instant messaging, "presence" (a user's availability for contact), location-based services, email and web. Further communication types are likely to be added in the t'uture.

This diverse collection of communication devices requires el't'icient session management due to the number of different applications and services that will be developed to support these communication types. The 3GPP has chosen Session Initiation Protocol (SIP) for managing these sessions.

The SIP protocol is a session-based protocol designed to establish IP based communication sessions between two or more end points or users. SIP is used as a means of signalling, end-to-end, the initiation, modification and termination of packet switched sessions. Once a SlP session has been established, communication between these end points or users can be carried out using a variety of different protocols (for example those designed for streaming audio and video). These protocols are defined in the SIP session initiation messages.

With IMS, users are no longer restricted to a separate voice call or data session.

Sessions can be established between mobile devices that allow a variety of communication types to be used and media to be exchanged. The sessions are dynamic in nature in that they can be adapted to meet the needs of the end users.

For example, two users might start a session with an exchange of instant messages and then decide that they wish to change to a voice call, possibly with video. This is all possible within the TMS l'ramework. If a user wishes to send a file to another user and the users already have a session established between each other (for example, a voice session) the session can be redefined to allow a data file exchange to take place. This session redefinition is transparent to the cud user.

IMS provides a separation of the "control plane" and the "user plane". The control plane performs the r equired signalling, and includes the relevant application protocol and the signalling bearer for transporting the application protocol messages.

Among other things, the application protocol is used for setting up the radio access bearer in the radio network layer. The user plane transmits data traffic and includes data streams and data bearers for the data streams. The data streams are charactcrised by one or more frame protocols specified for that interface.

Generally speaking, the user plane carries data for use by a receiving terminal - such as data that allows a voice or picture to be reproduced and the control plane controls how the data is transmitted.

Figure 1 shows the elements that allow a first terminal 1 to exchange data with a second terminal 3. The mobile terminal I communicates wirelessly with its home mobile telecommunications network 5 (that is, the network with which the user of the terminal 1 has a subscription) via a radio access network (RAN) - not shown.

The RAN handles subscriber access, and includes base stations and concentration nodes. Each RAN is associated with a serving GPRS support node (SGSN) - not shown. The SGSN handles the data traffic of users in a geographical service area.

Gateway GPRS support node (GOSH) 7 provides the interface between the radio network and an IP network (for example, it performs protocol conversion between the GPRS and IP environments). s

In the embodiment the GGSN 7 provides an interface between the mobil e telecommunications network 5 and IMS network 9.

In order to establish a communication session, the terminal 1 generates a packet data protocol (PDP) context. The PDP context defines parameters that support the flow of data traffic to and from terminal 1. Among the parameters that are set are the identifier of the external packet data network with which the terminal I wishes to communicate, a PDP address recognised in that network (for example, an IP address for service over the lntcrnct), the address of the GGSN 9, quality of service (QoS) parameters etc. The IMS network 9 includes a Proxy Call Session Control Function (P-CSCF) element l 1 that provides an initial interface between the data received from the GGSN 7 and the lMS network 9. The mobile terminal 1 obtains the address of the P-CSCF 11 either as part of the session management procedures performed when establishing lP connectivity (that is, the address of the P-CSCF 11 is provided during the PDP context activation process). Alternatively, the address of the P CSCF 11 may be resolved after the PDP context activation process through a dynamic host configuration protocol (DHCP) query/response process (in which case the mobile terminal I will request an IP address and other information in order to establish IP sessions).

Serving-CSCF (S-CSCF) element 13 provides session control. S-CSCF 13 is coupled to SIP application server 15 and Home Subscriber Server (HSS) 17. S CSCF 13 interacts with the SIP server 15 and HSS 17 to provide session control and security. The HSS 17 holds variables and identities for the support, establishment and maintenance of calls and sessions made by subscribers to mobile telecommunications network 5. This information includes the IMSI of each subscriber, security variables and location information.

Interrogating-CSCF (I-CSCF) element 19 allows subscribers of the mobile telecommunications network 5, or subscribers roaming in the network, to register with the network. The l-CSCF 19 deals with registration, routing and forwarding of SIP messages and charging.

The second mobile tcnninal 3 is registered with a second mobile l O telecommunications network 5A, which has associated with it elements corresponding to those described above in relation to the first mobile telecommunications network 5 with which mobile terminal 1 is registered. These elements of the second mobile telecommunications network 5A are designated with the same reference sign as the corresponding equivalent elements of the first mobile telecommunications network 5 but with the suffix "A".

Although in the embodiment described a communication session is established between the first mobile terminal I and the second mobile terminal 3 when those mobile tennhals are registered with respective mobile telecommunications networks 5 and 5A, it should be appreciated that the invention is also applicable to the establishment of the communication session where one of the terminals operates in a moblc telecommunications network and the other of the terminals operates in a different type of network, or where both the terminals are registered with the same network - which may be a mobile telecommunications network or other type of 2 5 network.

When a communication session is initiated by the mobile terminal 1 is it possible to access the lutcrnct 21 in a known manner via mobile telecommunications network 5 and GGSN 7, for example using WAP browser software present on mobile terminal 1. The user of mobile terminal I may obtain services from the Intennet 21 and may exchange data with mobile terminal 3 via the Internet 21. While such an arrangement allows the user of mobile terminal 1 to obtain a huge diversity of information and services from the Internet 21, there are significant disadvantages with such ar arrangement.

Firstly, the user of mobile terminal I will generally pay to access the Internet 21 on a per second or per byte basis. When the mobile terminal I connects to the Internet 21, a large amount of unwanted data (spam) may be transmitted to the mobile terminal 1 - for example as unsolicited emails or advertisements. The user of mobile terminal I will incur costs for obtaining this unwanted data because the user pays to receive data on a per second or per byte basis. The user of mobile terminal I pays to receive messages sent by others whether or not those messages are wanted.

This charging mechanism is sometimes referred to as "called party pays". Mobile telecommunications networks in Europe (except when a subscriber is roaming) operate on a "calling party pays" principle - that is, there is no charge for receiving a message or voice call. "Calling patty pays" is considered to be advantageous in many circumstances because the calling party has control of costs incurred and whether to incur costs by initiating a call.

When the Interpret 21 is accessed in the conventional manner, a portion of the per second or per byte charge collected by the mobile telecommunications network 5 with which the terminal I is registered is paid to the Interpret Service Provider (ISP) through which the communication is routed. I he ISP may in tuna pass some of its portion of the charge to another Interpret network. I-lowever, there is no straightforward mechanism for paying a provider of a specific service obtained by the user via the Internct. That is, there is no direct financial settlement between the two end parties of the communication.

Significantly, in the conventional Internet arrangement, there is no straightforward mechanism for establishing a relationship between the usefulness of the data to the user of mobile terminal l and the cost of obtaining the data.

The embodiment described aims to provide an improvement, which may be made available to the user of mobile terminal 1 in addition to or instead of access to the Internet 21 in the manner described above. In essence, an alternative internct 23 (that is, a set of interconnected networks and not necessarily the Internet) is provided which allows the exchange of data between respective mobile telecommunications networks 5,5A and other mobile and fixed telecommunications networks (not shown). A significant feature of the embodiment is that messages relating to a communication session transmitted via the internet 23 include information indicative of the particular service to which they relate. This facilitates the control of the messages sent and the communications session relating to a specific service.

Further, it enables a charge to be levied to the user of mobile terminal 1 for a particular service provided during the communication session. That is, the user need not be charged per second or per byte, but rather the user will incur a predetermined charge for being provided with a particular service. This is highly desirable for the user of mobile terminal I because, before initiating a request for a service, the user of mobile terminal I will know the costs that will be hcurrcd, and will know that, in exchange for payment of this know cost, a particular service will be provided. Also, it encourages service providers (which may not necessarily to operated or directly controlled by the mobile telecommunications networks) to provide high quality, good value services because they will be paid Ior the provision of the service rather than by some other mechanism. If the service is not requested and delivered the service providers will receive no payment.

Preferably, although not necessarily, the mobile terminals 1 and 3 are authenticated prior to accessing the internet 23. For example, the mobile terminal 1 is provided with, or associated with, authentication storage means for storing predetermined authentication information for authenticating that mobile terminal or a particular user thereof. In one arrangement, the authentication storage means for storing the predetermined infcnnation is removable and can thus be taken by the user and inserted into any terminal which is adapted to receive it, so as to enable that user to be authenticated in respect to a transaction to be canted out by that user with that terminal. Advantageously, in such a case the means for storing the predetermined infonnation is in the form of a smart card.

In a more specific example, the smart card is a Subscriber Identity Module or S1M of the type used in and for authenticating the use of handsets in a mobile or cellular telecommunications network (networks 5 and 5A in Figure 1) - such as a GSM (Group Special Mobile) or 3G (Third Generation) network. Such a network will store details of its users' (subscribers') SlMs. In operation of the network, a user's handset is authenticated (for example, when the user activates the handset on the network with a view to making or receiving calls) by the network sending a challenge to the terminal incorporating that STM, in response to which the SIM calculates a reply (dependent on the predetermined information held on the SIM typically an authentication algorithm and a unique key Ki) and transmits it back to the network which checks it against its own information for that user or subscriber in order to complete the authentication process. In the same way, thcrcforc, the SIM can be used in or in association with the terminal so that the same form of authentication proc ss can be carried out. In a case where the SIM is the S1M of a subscriber to a particular cellular telecommunications network, the authentication process can be canted out by that network.

It should be noted that the authentication process being described does not necessarily authenticate the human identity of the user. For example, cellular telecommunication networks have pre-pay subscribers who are issued with SlMs in return for pre-payment enabling them to make calls on the network. However, the identity of such pre-pay subscribers is not known (or not necessarily known) by the networks. Nevertheless, such a user cannot make use of the network until the network has authenticated that user's SIM - that is, has confinned that such user is a particular user who has a particular pre-paid account with the network. The SIMs of such pre-paid users or subscribers could equally well be used (in the manner described) in or in association with data processing apparatus or computers, for the purposes of authenticating that user.

The SIM need not take the form of a physical (and removable) smart card but instead can be simulated by being embedded in the data processing apparatus or computer in the form of software or represented as a chip for example.

In addition to authenticating a user/terminal with the network in order to obtain communication services from the network, the authentication process may facilitate a transaction between the terminal and a third party. Where the authentication process is carried out by a telecommunications network, or by some other system, to which the user of the SIM is a subscriber, the satisfactory completion of the authentication process would then be communicated by that network or system to the third party -- to enable the transaction to proceed.

For many transactions of the type described, a payment by the user to the third party may be involved. An arrangement as described above, in which the authentication process is carried out by a telecommunications network or other centralised system to which the user is a subscriber may facilitate the making of such payments and can be advantageous where (as may often be the case) the payment is for a small amount (for example, payment in return for receipt of information - e.g. weather or traffic information, or for temporary use of specific software); in such a case, the payment can be debited to the account of the subscriber held by the telecommunications network or other centralised system - and then, of course, passed on to the third party, perhaps after deduction of a handling charge.

The authentication for performing a transaction may be preformed by the mechanism described in the applicant's co-pending patent application No. GB0224228.7 and in W020040368((,, which are hereby fully incorporated by reference.

However, the present embodiment is primarily concerned with obtaining a service from internet 23. As described above, the mobile terminal I is authenticated with network 5 using the SIM present in mobile terminal 1. A PDP context is created to connect to IMS network 9 via GGSN 7. Connection to intennet 23 is via a gateway 25, which controls access to the IMS network 9 and enforces any required policies relating to use of the interact 23. The gateway 25 may include a mechanism for blocking unsolicited messages from passing from the internet 23 to the IMS network 9. A corresponding gateway 27 is provided between the internet 23 and the second IMS network 9A. Further, third party service providers 29 and 31 may also access the intendant 23 via their respective gateways 33 and 35.

In figure 1 the solid line 37 shows the control plane signalling and the dashed line 39 shows the user plane signalling. The control plane signalling may implement services by means of the SIP application server 15 - for example, application implementation and execution, integration of services, collection of charging information and interconnection for message handling. The control plane signalling may also, via P-CSCF 11 and I-CSCF 13, perform call/session control, collection of charging information, message routing and interconnection handling, and provide messaging services based on "pager mode" and massaging and communication services based on "session mode". The user plane signalling provides bearer connectivity and control, and services such as voice calls, videotelephony, "chat" and browsing using the conventional Tnternet 21.

The interact 23 may for example be a GPRS roaming exchange (GRX) network of generally known type or any alternative IP network intended for the same or similar purpose. GRX networks provide an interface that connects together mobile telecommunications networks and allows the transmission of IP based eornnunieations between respective mobile telecommunications networks.

Conventional GRX networks allow a roaming mobile terminal user to send and receive GPRS traffic when away form their home network. The GRX network controls the routing of the IP data packets so that they are delivered to the appropriate address.

In accordance with the embodiment, if, for example, the user of mobile terminal 1 wishes to play a computer game against the user of mobile terminal 3, the user may select this service using the graphical user interface (for example a menu) of the mobile terminal 1. The user will also select the user of mobile terminal 3 as the patty with whom they wish to play the game. The mobile tenninal I then generates an appropriate POP context which is used it to establish a communications link with IMS network 9. The nature of that the service request is recognised by the IMS network 9 and appropriate data pachcts for providing the requested a gaming service on generated. These data packets arc for transmission to the mobile terminal 3 via intcrnet 23 and the intermediate components. In accordance with an important feature of the embodiment, the data packets are not sent in the conventional manner as IF data packets that may be received by the user of mobile terminal 3 that user making a separate, independent connection to the internet 23 (which will be paid for by the user of mobile terminal 3). Such a conventional arrangement would result in the users of both mobile terminals I and 3 being charged on a per second or per byte connection to internet 23. Instead, the request by the user for game play is treated as a request for a particular service which has a predetermined cost to the user (for example, a fiend cost for completion of a single game). The lMS network 9 generates data packets to allow signalling between the mobile terminals I and 3 via the internet to allow game play. The nature of this signalling will be known to those skilled in the art and is not discussed further here. However, each data packet includes a component that identifies the data packet as relating to the particular service. For example, the data packet includes the following components: the identity of mobile terminal 1, the game to be played and the identity of mobile terminal 3. This allows the internet 23 to recognise that a data packet is for a particular service. The interact 23 (which may be owned and operated independently of the mobile telecommunications networks 5 and SA) may render a charge for carrying the data packets, in respect of that service, to the network 5. The charge to the user of mobile terminal 1 (the network of the "calling party") for game play will be set with the expectation that such charges for data packet transmission will be incun ed.

The charging mechanism described above is significantly different Tom the conventional Interact model. In the conventional lntenet model, the each network within the Internct might make a charge to the mobile telecommunications network I in dependence of the total amount of data carried over a particular period (for example, one month). There is no straightforward mechanism for reconciling these charges with particular services provided to particular subscribers of the mobile telecommunications network.

The internet 23 may comprise a plurality of separate networks or carriers (similar to the Internet). The component that identifies the data packet as relating to the particular service is recognisable to each of the networks or carriers, and each may l O make a charge for data transmitted in respect of that service to the mobile telecommunications network 1. Figure 2 illustrates such an arrangement.

In Figure 2 the internet 23 includes four carriers A, B. C and D which carry a data packet between mobile terminal l and mobile terminal 3 (various intermediate components have been omitted fiom Figure 2 for the sake of simplicity). Each carrier will render a charge to the originating network 5 for carrying the data packet, as will the terminating network 5A. For example, carrier A will charge O.Olp, carrier B will charge 0. 005p, carrier C will charge O.Olp, carrier D will charge 0.002p and terminating network 5A will charge O.lp. The tariff charged by mobile network 5 for the service would be such as to recoup these costs from the subscription of the mobile terminal I with the network.

The arrangement shown in Figure 2 could be considered as analogous to the mechanism for charging a roaming subscribed making a conventional circuit switched voice call. The roamed network will make a charge to the home ol the subscriber for carrying the call, and this will be passed to the subscriLcr by an appropriate roaming tariff. This Is relatively straightforward to achieve because, for example, GSM networks were dcvclopcd to allow roaming. The calling party is known to the carrier because their IMSI is transmitted as part of the circuit switched signalling. This is not the case for conventionally transmitted IP packets over the Internet.

S However, the interpret 23 (and/or networks comprising the interpret 23) are not necessarily specifically designed for providing mobile telecommunications services - they may be any type of network capable of transmitting data packets. Flowever, by including in the data packet an indicator of the service to which it relates, the present embodiment allows charges to be based on use of a service.

In the embodiment there is no requirement for an end-to-end commercial agreement to exist between each of the carriers A, B. C and D. To set up such an end-to-end commercial agreement is time consuming and complex. Any requirement for an end-to-end commercial agreement would restrict the flexibility of the interact 23 because data packets could only be transmitted through particular carriers in a particular order. In the embodiment, the data packets can be transmitted via any carrier available. The carrier is able to identify the particular service to which the data packet relates and may render a charge for carrying the data packet in respect of that service by sending an appropriate request to the network 5 with which mobile terminal l is registered. In agreement and protocol between the carriers of the internet 23 facilitates the rendering and payment of such charges.

An agent may create an agreement between each of the carriers and offer a service to mobile networks 5 and SA (and other networks that access the interact 23) for delivering data packets across a plurality of carriers. A fee charged to a network by the agent for use of the carriers will be partially apportioned to those carriers when the are used.

The arrangement described above in respect of the interact 23 may allow standardised data compression techniques to be used for the transmission ot' data packets.

The charges rendered by the respective carriers or agents may include a charge to purchase rights to use "content", such as a movie clip.

I'he charging on the basis of a particular service may be varied in dependence upon network capacity in order to smooth or equalise available transmission capacity. Although the use of a GPRS terminal is described above, it should be

appreciated that the terminals could be 3G(UMTS) terminals or a terminal using any suitable technology that is able to originate messages that can be carried across the other networks. The terminals are not necessarily mobile terminals.

In the embodiment described above it is indicated that the "calling party pays" principle will be applied. In a communication session between two terminals transmitting data in the 11' domain, both terminals will generally transmit and receive data during the communication session. In such an arrangement the calling party can be considered to be the party that initiated the communication session.

Further, it is important to appreciate that the present invention is not restricted to an arrangement where the calling or communication session initiating party pays for a particular service. The embodiment described provides an arrangement where the data packets transmitted include information indicative of the service to which they relate. This allows a charge to be made that relates to a particular service. This information allows any party to be charged in a controlled manner. For example, instead of the calling or communication session originating party paying, a recipient might pay.

For example, if a user uses their terminal to access a search engine (such as Google) to do an Internet search, the user of the terminal might be charged by the search engine, which charge covers the cost of the data both sent from and received by the terminal. In another example, if the user of a terminal communicates with a retailer to order and pay for goods electronically, that retailer might choose to pay for the communication session as part of its customer service. A different arrangement, 1() again, might apply when a user of a first terminal wishes to play a game with the user of a second terminal. The user that is charged for the game play might be the user that loses the game. Phe charge levied to the user might include a component which is credited to the winner of the game.

Claims (39)

CLAIM S

1. A method of enabling a first device to use a service provided via a data communications network linking the first device to a second device, the method including routing messages between the first device and the second device via the data communications network, wherein the messages include information indicative of the service to which they relate.

2. The method of claim 1, wherein each message comprises a discrete data I O packet.

3. The method of claim I or 2, including analyzing the information indicative of the service to identify the service to the data communications network.

4. The method of claim 1,2 or 3, wherein the data communications network includes a mobile telecommunications network and wherein the first device is coupled to the data communications network via the mobile telecommunications network.

5. The method of claim 4, wherein the first device is a mobile telecommunications device for communicating wirelessly with the mobile telecommunications network.

6. The method of any one of claims 1 to 5, wherein the data communications network includes a mobile telecommunications network, and wherein the second device is coupled to the data communications network via the mobile telecommunications network.

7. The method of claim 5, wherein the second device is a mobile telecommunications device for communicating wirelessly with the mobile telecommunications network.

8. The method of any one of claims 1 to 7, wherein the data communications network includes an Interpret Protocol (IP) based network.

9. The method of any one of claims I to 8, wherein the data communications network includes a plurality of data carriers linked together for relaying the to messages between the first device and the second device.

10. The method of claim 9, including identifying each of the carriers through which messages relating to a particular service are passed such that a payment can be made to each of the carriers tor facilitating provision of the particular service.

l l. The method of claim 10, including rendering a charge to the account of the first device with the data communications network for providing the particular service and for allocating a portion of said charge to each of said carriers.

12. The method of any one of claims I to l l, wherein the data communications network comprises a Global Roaming Exchange (GRX)

13. The method of any one of claims l to 12, wherein the data communications network includes a network that has no direct commercial relationship with other networks of the data communications network.

14. The method of any one of clangs I to 13, wherein the first and/or the second device comprises a GPRS mobile telecommunications terminal.

15. The method of any one of claims 1 to 14, wherein the messages include data components and signalling components, the signa]]ing components being used by the data communications network to control the transmission of the data components.

]6. The method of any one of claims I to 15, wherein the messages include Session Initiation Protoco] (SIP) components.

17. The method of any one of claims 1 to 16, wherein the data communications network includes an IP Multimedia Subsystem (IMS).

18. The method of any one of claims t to 17, wherein the service includes any one of Voice over Intenet Protocol (VolP), Intemet Protocol Telephony, the transmission of a Multi Media Message (MMS), voice data, video telephony data and peer-to-peer gaming data.

19. A system for enabling a first device to use a service provided via a data communications network linking the first device to a second device, the system including means for routing messages between the first device and the second device via the data communications network, wherein the messages include information indicative of the service to which they relate.

20. The system of claim 19, wherein each message comprises a discrete data packet.

21. The system of claim 19 or 20, including means for analyzing the information indicative of the service to identify the service to the data communications network.

22. The system of claim 19,20 or 21, wherein the data communications network includes a mobile telecommunications network and wherein the first device is coupled to the data communications network via the mobile telecommunications network.

23. T he system of claim 22, wherein the first device is a mobile telecommunications device for communicating wirelessly with the mobile telecommunications network.

24. The system of any one of claims 19 to 23, wherein the data communications network includes a mobile telecommunications network, and wherein the second device is coupled to the data commmications network via the mobile telecommunications network.

25. The system of claim 24, wherein the second device is a mobile telecommunications device for communicating wirelessly with the mobile telecommunications network.

26. The system of any one of claims 19 to 25, wherein the data communications network includes an Internet Protocol (IP) based network.

27. the system of any one of claims 19 to 26, wherein the data communications network includes a plurality of data carriers linked together for relaying the messages between the first device and the second device.

28. The system of claim 27, including identifying each of the carriers through which messages relating to a particular service are passed such that a payment can be made to each of the carriers for facilitating provision of the particular service.

29. The system of claim 28, including rendering a charge to the account of the first device with the data communications network for providing the particular service and for allocating a portion of said charge to each of said carriers.

30. The system of any one of claims 19 to 29, wherein the data communications network comprises a Global Roaming Exchange (GRX).

31. The system of any one of claims 19 to 3(), wherein the data communications network includes a network that has no direct commercial relationship with other networks of the data communications network.

32. The system of any one of claims 19 to 31, wherein the first and/or the second device comprises a GPRS mobile telecommunications terminal.

33. The system of any one of claims 19 to 32, wherein the messages include data components and signalling components, the signalling components being used by the data communications network to control the transmission of the data components.

34. Ihe system of any one of claims 19 to 33, wherein the messages include Session Initiation Protocol (SIP) components.

35. The system of any one of claims 1') to 34, wherein the data communications network includes an IP Multimedia Subsystem (IMS).

36. The system of any one of claims 19 to 35, wherein the service includes any one of Voice over Internet Protocol (VolP), Internet Protocol Telephony, the transmission of a Multi Media Message (MMS), voice data, video telephony data and peer-to-peer gaming data.

37. A method of providing a service to a device registered with a first communications network, the service being provided via a second communications network, the method including generating a plurality of data packets for transmitting data relating to the service via said second communication network, each of said data packets including an element that identifies the particular request for service and is interpretable by the second communication network such that the second communication network can obtain payment from the first network form transmitting the data packet in respect of that service.

38. A method of enabling a first device to use a service provided via a data communications network linking the first device to a second device, substantially as hereinbefore described with reference to and/or substantially as illustrated in any one of or any combination of the accompanying drawings.

39. A system for enabling a first device to use a service provided via a data communications network linking the first device to a second device, substantially as hereinbefore described with reference to and/or substantially as illustrated in any one of or any combination of the accompanying drawings.