MXPA00002912A - Gprs-subscriber selection of multiple internet service providers - Google Patents

Abstract

A switching device (PLMN-SW) in a mobile radio communication system (PLMN) which supports a GPRS-network allows to connect a terminal station (GPRS-MS) of the mobile radio communication network (PLMN) with one of a plurality of packet data communication networks (PDN1, PDN2, IN). The selection of the packet data communication network (PDN1, PDN2, IN) is based on the transmission of a specific network indication parameter (NIP) from the terminal station (GPRS-MS) of the mobile radio communication network (PLMN). The network indication parameter (NIP) is transmitted to a serving (GPRS) support node (SGSN) as a special parameter in a PDP context activation procedure. Thus, a large number of internet service providers (ISP1, ISP2, ISP3) can be connected to a GPRS-network.

Description

SELECTING A GPRS SUBSCRIBER FROM MULTIPLE INTERNET SERVICE PROVIDERS FIELD OF THE INVENTION The invention relates to a method, a switching device, a telecommunications system and a terminal station, in particular, to a GSM-based General Pa and Radio Service (GPRS, Packet Radio Service, General , based on GSM), which allows a subscriber station to select a predetermined network of various packet data networks (PDN) connected to a gate GPRS support node (GGSN). Packet data networks can be of any kind of packet data network or Internet Service Providers (ISP, Internet Service Providers).

BACKGROUND OF THE INVENTION The standardization of the GSM General Packet Radio Service (GPRS) is currently in progress at the European Telecommunication Standards Institute (ETSI, European Institute of Telecommunications Standards). The GPRS is a new GSM service that offers real-time access to packet radio communications for mobile users in GSM. According to the GPRS system, radio communications resources are reserved only when there is something to send (due to the nature of the packets of this system) and the same radio resource is shared by all the mobile stations in a cell, providing use effective of scarce resources. The GPRS facilitates a variety of applications, such as telemetry, train control systems, interactive data access, tariff charging systems and Internet exploration using WorldWide e. Contrary to the circuit switching nature of the GSM network, the operation of the GPRS is adapted to provide a connection to a standard data network (using protocols such as TCP / IP, X.25 and CLNP). In contrast, conventional GSM was originally designed to offer only voice assignments by circuit switching. The infrastructure of the packet-oriented GPRS network introduces new functional elements that will be briefly described below with reference to Figure 1. It should be noted that there is still some cooperation between elements of the current GSM services and the new GPRS network. In the physical layer it is possible to reject resources if there are some common signaling characteristics. On the same radio carrier there may be time slots reserved simultaneously for use in circuit switching and GPRS. The most optimal resource utilization is obtained through the dynamic sharing between circuit switching channels and GPRS. During the establishment of a circuit switched call, there is still enough time for the forced release of the GPRS sources for switched circuit cells having higher priority.

Interaction of the GSM network and the GPRS network Figure 1 is a simple overview of the interaction of the characteristics of the switched circuits of the GSM and the elements of the GPRS system of switched packets. The support node of the GPRS GSN is the main element and offers connection and interworking with different data networks, mobility management by means of the GPRS registers and of course the sending of the data packets to the mobile stations GPRS-MS independently of your location. Physically, the GSN can be integrated into the Mobile Switching Center (MSC) of the PLMN (Public Land Mobile Network, Mobile Public Network, Terrestrial). Otherwise it can be a separate network based on the architecture of the network's data routers. User data flows between the GSN and the subsystem of the base station (BSS) and signaling is exchanged between the MSC and the GSN. Thus, the GPRS offers a bearer service from the limit of a data network to a GPRS MS. The users of the bearer service are the software packages of the layers in the public network (such as Ip, OSI, CLNP and X.15). Also, the applications GPRS-specific services will use the GPRS service. GPRS uses a packet mode technique to transfer data at high speed and low speed and signaling in an efficient way. GPRS optimizes the use of network resources and minimizes the load on the radio system. A strict separation between the radio subsystem and the network subsystem is maintained, allowing the subsystem of the network to be reused with other radio access technologies. GPRS as such does not order changes to an installed MSC base. New radio channels of the GPRS are defined and the allocation of these channels is flexible: from 1 to 8 time slots of the radio interface can be assigned per TDMA frame and the time slots are shared by active users with the uplink and downlink assigned separately. The sources of the radio interface can be dynamically shared between voice and data services as a function of the service load and operator preference. Different encoding schemes of radio channels are specified to allow bit rates from 9 to more than 150 Kbyte / sec per user. It is still estimated that a data rate without processing of up to 200 Kbyte / sec can be obtained per user. As already explained, applications based on standard data protocols are supported and defined by interworking with IP networks and X.25 networks. Specific point-to-point and point-to-point services are supported for applications such as traffic telemetry and UIC train control. The GPRS also allows a short message service (SMS) to transfer over the GPRS radio channels. GPRS is designed to provide support from intermittent and burst data transfers to occasional transmission of large volumes of data. Four different levels of Quality of Service (QoS, Quality of Service) are supported; QoS are initially established during an activation procedure in the context of the PDP as will be explained later). The GPRS is designed for quick booking in order to start a packet transmission, from 0.5 to 1 second. The cost will usually be based on the amount of data transferred due to the nature of the packet transmission.

Terminal stations with GPRS support Three different classes of GPRS mobile stations are supported in the GPRS: one MS class A can operate GPRS and other GSM services simultaneously. A class B MS can monitor control channels for the GPRS and other GSM services simultaneously, but can only operate one set of services at a time. An MS of the GPRS class C can operate exclusively GPRS services.

Transmission of data packets Having generally established the GPRS support nodes, GSN, in Figure 1, of course one of the main problems in the GPRS network is the routing of the data packets to and from a mobile station MS . This problem can be divided into two sub-problems, namely, the routing of the data packets and the handling of mobility. Routing the data packets to a mobile station MS is a problem in the GPRS network, since the data network address of the mobile station usually has a static routing mechanism, while the mobile station MS can wander from one network to another. An approach for a routing of data packets in a mobile environment is the concept of mobile IP.

(C. Perkins (editor): "IP Mobility Support, draft ietf-mobileip-protocol-ll.txt", July 1995, work in progress in the Internet Engineering Task Force). The IP of the mobile allows the routing of IP datagrams to mobile hosts, independent of the subnet of the junction point. Another method is taken in the system for data in digital, cellular (CDPD) packets where routing to the mobile host is handled internally by the network (CDPD Industry Input Coordinator, "Cellular Digital Packet Data System Specification", version 1.0, July 1993 ). The IP concept of the standard mobile does not fit exactly in the GPRS environment because of the requirement that network protocols in addition to the IP must also be supported. Therefore, for the routing of the data packets the structure of the telecommunications network of Figure 1 (comprising the general GPRS nodes GSN) is constructed in a concept similar to that of the mobile IP concept as shown in the Figure 2.

GPRS support nodes In Figure 2, the GPRS introduces two new network nodes in the PLMN in GSM: the support node of the GPRS server (SGSN), which is at the same hierarchical level as the MSC (Switching Center) Mobile) tracks the location of individual mobile stations and performs security and access control functions. The SGSN is connected to the base station system with frame relay. Thus, the main functions of the SGSN are to detect new MS of the GPRS in its service area, to handle a registration process of the new MS in the GPRS registers, send / receive data packets to / from the GPRS MS and maintain a record of the location of the MS within their service area. The subscription information is stored in a GPRS record where the mapping is stored between the identity of a mobile station (such as MS-ISDN or IMSI: international mobile station identity) and the address of the PSPDN. The GPRS registry acts as a database from which the SGSNs can ask if a new MS in their area is allowed to join the GPRS network. The gateway GSN (GGSN) provides interworking with external packet switching networks and is connected to the SGSNs via an IP-based GPRS main network (IP: Internet Protocol). The aforementioned GPRS records may be provided in the HLR which in turn is enhanced with the GPRS subscriber information. Optionally, the MSC / VLR can be improved for more efficient coordination of the services and functionality of the GPRS and non-GPRS: for example, paging of circuit switched calls that can be performed more efficiently through the SGSN and updating the location of the GPRS and non-GPRS combined. As also shown in Figure 2 (although not relevant in the present application), of course the SGSN cooperates with a gateway MSC for short message services, SMS-GMC, through an MSC interworking with short message services (SMS-IWMSC). In addition, it should be noted that the SGSN performs authentication and codifies the characteristics of the establishment based on the same algorithms, keys and criteria as in the existing GSM. The GPRS uses an optimized coding algorithm for packet data transmission.

Access to the GPRS through a mobile station In order to access the GPRS services, the mobile station must first let the network know of its presence by making a connection to the GPRS. This operation establishes a logical link between the mobile station and the SGSN and makes available to the mobile station for the SMS over GPRS, performing the search through the SGSN and notification of incoming GPRS data. To send and receive data from the GPRS, the mobile station must activate the packet data address (PDN address) that it wants to use. This operation makes the mobile station known in the corresponding GGSN and can begin interworking with external data networks. The user data is transferred transparently between the mobile station and the external data networks with a procedure known as encapsulation and tunneling (the exchange of tunneling messages is part of the activation procedure in the PDP context): the packets of data are equipped with GPRS specific protocol information and are transferred between the mobile station and the GGSN. This transparent transfer method reduces the requirement for GPRS PLMN to interpret internal data protocols and allows the easy introduction of additional interworking protocols in the future. User data can be compressed and detected with retransmission protocols for efficiency and reliability. Thus, the support node of the GPRS in its general form (GSN) contains the functionality required to support the GPRS. In a PLMN; there may be more than one GSN as seen in Figure 3. The gate GPRS support node (GGSN) is the node to which the packet data network has access due to the evaluation of the so-called PDP address. This address contains routing information for the subscribing GPRS users. The routing information is used to tunnel the protocol data units (PDUs) to the current junction point of the mobile station, i.e. to the respective GPRS support node (SGSN) server. The GGSN can request location information from the HLR through the optional Ge interface, is the GGSN the first point of interconnection of the PD? (data network in packages). with a PLM? in GSM, supporting the GPRS (ie, the Gi reference point is supported by the GGS?).

Intranets and internets connected to the GPRS While Figure 1 shows the general structure of the incorporation of GPRS functionalities in a GSM system, figure 3 shows additional networks within the PLM? necessary as the main GPRS networks. The intra-PLMN main network is the protocol network of Internet interconnecting the GS? within the same PLM ?. The main inter-PLM network? is the IP network interconnecting the GSM and intra-PLM main networks? in different PLM ?.

Each intra-PLM main network? is a private IP network proposed only for GPRS data and GPRS signaling.

This private IP network is an IP network to which an access control mechanism is applied to obtain a necessary level of security. The main networks intra-PLM? are connected through the Gp interface using gates in the limit (BG) and an intra-PLM main network ?. The main inter-PLM network? it is selected through a roaming agreement (roaming unit) that includes BG security functionality. BGs are not defined within the scope of GPRS. The intra-PLMN main network can be a packet data network. For example, the intra-PLMN core network can be a corporate network and the packet data network can be. a public Internet or a leased line. Finally, the HLR shown in Figure 2 contains the GPRS subscription data and routing information. This HLR is accessible from the SGSN through the Gr interface and for roaming mobile stations MS, the HLR may be in a PLMN different from the current SGSN to which the mobile station is connected. Therefore, in Figure 3 the HLR can be located in the PLMN A or PLMN B.

Example of GPRS communication Having described the general architecture of the GPRS system in Figures 1-3, Figure 4 shows an illustrative example of how it is possible to perform information routing in this system. As shown in Figure 4, within the mobile communication system GPRS there are three different routing schemes and therefore three examples of possible applications for the present invention are as follows: - message originating in the mobile (route Pl) - finished message in a mobile when the mobile station (MS) is in its local network (route P2); and - message terminated on the mobile when the mobile station (MS) has been passed (roamed) to a network of another GPRS operator (route P3). As in Figure 3, also in Figure 4, the operator's GPRS network consists of multiple GSNs and an intra-operator main network [sic]. The intra-operator main network connects carrier support nodes using operator-specific network protocols that may be different for each operator. With interworking capabilities, however, the GGSN can be connected to the data networks and to a main inter-operator network connecting the GPRS networks of different operators using a normal protocol. The main benefits of this proposed architecture are its flexibility, the possibility of scaling and interoperability. This approach allows each PLMN operator A, B to implement an individual master network using any protocol, through communications even though other GPRS operators are implemented using only a common protocol. ETSI has selected IP vß to be the main protocol in the future. IP v4 has been selected as the intermediate principal protocol. As seen in Figure 4, from the point of view of the data network, the GPRS network resembles a subnet in the data network. For example, on the Internet, the GGSN acts as an IP router behind which the entire GPRS network is hidden. A computer in the Internet network then sees the GPRS as an IP subnet to which messages are sent as if the GPRS network were a completely normal Internet implementation. The routing mechanism in the data network is then exactly the same as in the case of the normal Internet receiver. According to a first example of the data routing shown in Figure 4 and being related to the Pl route, the mobile station of the GPRS sends a data packet, that is, a data unit in PDU packets of a public network data in PSPDN switched packets to a data network. The PSPDN PDU data packet is sent using the LLC (Logical Link Control) protocol over the air interface to the server support node of the GPRS SGSN currently serving the MS mobile station of the GPRS. In the event that the GPRS Serving Support Node (SGSN, GPRS Server Support Node) has received the data packet without error, it encapsulates the PSPDN PDU data packet in the GPRS main network data packet which is sent to the gate support node of the GPRS (GGSN) handling the traffic from the mobile station MS of the GPRS to the data networks. GPRS gateway support nodes GGSN de-encapsulates the PSPDN PDU data packet and sends it to the appropriate data network. As shown in Figure 4, a second example for the application of the invention relates to the P2 route where a host in a data network is sending a PSPDN data pack PDU to a mobile MS station of the GPRS located in the network Local GPRS. In this case, compared to the first example outlined above, the PSPDN PDU data packet is routed in the reverse direction using the routing mechanisms in the data network until the PSPDN PDU data packet arrives at the gate support node of the gateway. GPRS GGSN. In the gate support node of the GPRS, the address of the PSPDN of the mobile station MS of the GPRS is extracted and the current location of the mobile station MS of the GPRS is determined or mapped. Then the routing of the PSPDN PDU data packet is performed in the local GPRS network. A) Yes, the PSPDN data pack PDU is first encapsulated in a main network and then sent to the server support node of the GPRS SGSN currently serving the mobile station MS of the GPRS. The last example modified in Figure 4 refers to the route P3 and is almost identical to Example P2. In this case, the mobile station MS of the GPRS has switched to another GPRS network and the local GPRS network must send the PSPDN PDU data packet over the main inter-operator network to the visited GPRS network. Thus, in accordance with this example, an additional GPRS gate support node, GGSN, is involved to provide the data packet to the mobile station MS of the GPRS roaming. Then, the visited GPRS network routes the PSPDN data pack PDU in addition to the appropriate GPRS server support node, as mentioned above with respect to the second example.

Procedure Log-on of the GPRS-MS A common log-on procedure (communication initiation) of a mobile station MS of the GPRS -who wishes to transmit the data packets is shown in Figure 5. The main objective of this procedure log-on is to send the address in the PSPDN of the mobile station MS of the GPRS to the GPRS network, to report on the details of the current location of the mobile station MS of the GPRS, to create entries for the address in the PSPDN assigned in the routing table of the gate support node of the GPRS GGSN and to initiate the charge in the statistical procedures, respectively. During the GPRS log-on procedure, the context (the content of the series of parameters) of the logical link between the MS and the SGSN is established using the independent dedicated control channel in GSM (SDCCA) as a bearer.

During setting the context, the mobile station of the GPRS is also authenticated and the parameter coding is exchanged between the mobile station MS of GPRS and the supporting node server of the GPRS, SGSN, (this authentication / coding procedure is carried out separately from the activation of the PDP context described below, see GSM document 03.60). The record is then sent to the gate support node of the GPRS in which the location of the mobile station of the GPRS is updated. Here, the GPRS gateway support node GGSN can inform a server support node of the GPRS, SGSN, to remove the mobile station MS from the GPRS from the previous registers. In the event that the GPRS log-on procedure is successful, the GPRS mobile station enters the paused state. Finally, the GPRS mobile station can exit the GPRS service by initiating a GPRS log-on procedure similar to the log-on procedure.

Activation procedure in the PDP context In the PDP context activation, the SGSN establishes a context called PDP that will be used for routing purposes within the GPRS PLMN with the GGSN that the GPRS subscriber is using. Figure 6 shows the PDP context activation procedure. A point-to-point GPRS subscription (PTP) contains the subscription of one or more PDP addresses (for example, in the HLR). Each PDP address is described by an individual PDP context in the mobile station MS, the SGSN and the GGSN. Each PDP context exists independently in one of two PDP states. The PDP state indicates whether the PDP address is activated for data transfer or not. All PDP contexts of a subscriber are associated with the same MM context for the IMSI of this subscriber. Thus, the PDP context is a series of information held in the mobile station MS and the GSNs for the PDP address as described in "Digital Cellular Telecommunication System" (phase 2+); General Communications Services in Packet Radio (GPRS); GPRS tunneling protocol (GTP) through the Gn and Gp interface; (GSM 09.60 proposed version 1.1.0), proposed Draft TS100 960 VI .1.0 (published by the European Telecommunications Standards Institute ETSI, June 1997). Upon receipt of an activated PDP context request message, the SGSN must initiate procedures to establish the PDP contexts. Therefore, a valid request initiates the creation of a tunnel between a PDP context and an SGSN, and a PDP context in a GGSN. That is, after a successful PDP context activation procedure, during or after the log-on procedure in Figure 5, an agreement has been made for a PDP context between the SGSN and the GGSN (and thus the GPRS mobile station) , which will be used for the transmission of data in packets. The list of information parameters in the PDP context is shown in table 5 of GSM 0360 proposed version, document 2.0.0 (published by ETSI, May 1997). The traditional PDP context activation procedure in Figure 6 comprises the following four steps Sl, S2, S3, S4. In step Sl, the mobile station MS sends an activated PDP context request message (TLLI, requested QoS, NSAPI) to the SGSN. The mobile station MS indicates that you want -using a dynamic PDP address by selecting an NSAPI (identifier of the service access point in the network layer) referring to a PDP context indicating a dynamic address of the desired type. In step S2, the security functions are executed. In step S3, the SGSN checks that the NSAPI matches a PDP context in the subscription data that was stored in the SGSN during the start of the GPRS communication (join). If the mobile station MS requests a PDP context with dynamic address, then the SGSN allows a GGSN to assign the dynamic address (the GGSN used is the address of the GGSN stored in the PDP context or, if this field is empty, a suitable GGSN chosen by the SGSN). The SGSN can limit the necessary QoS values given its capabilities, the current load and the subscribed QoS level. • Thus, in step S3 ', the SGSN sends a request message create PDP context (IMSI, PDP PDP type, PDP address, negotiated QoS, TID) to the affected GGSN. The PDP address is set to zero if dynamic address is requested. The GGSN creates a new entry in its PDP context table. The new entry allows the GGSN to route the PPD PDUs between the SGSN and the external PDP network. In step S3", the GGSN then returns to the SGSN a response message to create context PDP (TID, PDP address, protocol BB, cause) the PDP address is included if the GGSN assigns a PDP address. TCP or UDP is used to transport the user data over the main network between the SGSN and GGSN The messages creating PDP context are sent over the main GPRS network In step S4, the SGSN inserts the PDP address received from the GGSN into its PDP Context The SGSN returns an Activate PDP Context Accept message to the MS (accepts activate PDP context) (TLLI, PDP type, PDP address, NSAPI, negotiated QoS, cause) After step S4, the SGSN can now route the PDPs PDU between the GGSN and the mobile station MS For each PDP address a different quality of service (QoS) may be requested For example, some PDP addresses may be associated with electronic mail (e-mail) which can tolerate long response times . Other applications may not tolerate delays and demand a very high level of performance, with interactive applications being an example. These different requirements are reflected in the QoS parameter. The QoS values are defined in GSM 02.60. If a QoS requirement is beyond the capabilities of a PLMN, the PLMN negotiates the QoS as close as possible to the requested QoS. The MS accepts the negotiated QoS or disables the PDP context. After an SGSN has successfully updated the GGSN, the PDP contexts associated with an MS are distributed as shown in the "storage of information" sub-clause of GSM 03.60. If the PDP context activation procedure fails or if the Cause parameter accepts to activate the PDP context it indicates a rejection, then the MS may attempt another activation to the same PDP address up to a maximum number of attempts. While each mobile GPRS station should always perform the procedure in Figure 6, further details of the modified PDP context activation procedures can be taken from the two aforementioned ETSI documents (which also give a description of other abbreviations used for the parameters in the above description generally known to experts in mobile communications).

PRIOR ART PUBLISHED As already described with reference to Figures 1-6, a transmission of data packets using GPRS facilities in a traditional GSM system, a first terminal station of a mobile telecommunications radio network can also perform a data communication in packets with a second terminal station attached to a packet data communications network. In EP 0 711 088 A2, which describes the features of claims 1, 11, 21 and 31, some other details of the use of GPRS facilities in GSM are described. In particular, it is described that one of eight physical TDMA channels in the GSM system is special for the GPRS system and that the first terminal station will be using packet radio communication to establish GSM connection with a GPRS service through the GSM channel PRMA COMPENDIUM OF THE INVENTION As already explained, to allow a packet data transmission from a GPRS MS mobile station to a packet data network that supports a packet data protocol such as IP or X.25 (which is connected to GGSN) in Figure 1 to 4, it is necessary that a communication initiation procedure (log-on) or PDP context activation procedure is performed as described with reference to Figure 5, 6. This activation procedure is used. to create a tunnel between a PDP context in an SGSN and a PDP context in a GGSN. In essence, the PDP context can be seen as a series of agreed parameters between the SGSN and the GGSN for a packet transmission using a specific protocol. The common parameters that have traditionally been used in this series of parameters are the MS-ID, the QoS, the NSAPI, the TEPI and the PDP address. In particular, a GPRS subscriber identified by an IMSI must, once he has one or more addresses at the network layer, ie PDP addresses, temporary, and / or permanently associated with it, be in accordance with the scheme standard addressing of the service of the respective network layer that is used, for example: - an IP version 4 address; - an IP address version ß; or - an X.121 address. The PDP addresses are activated and deactivated through the MM procedures described in the "Activation and Deactivation Functions of the PDP Context" sub-clause in the document GSM 03.60. Once the tunnel has been established by activating the PDP context, a packet data transmission can be performed as explained for Examples 1, 2, 3 in Figure 4. It should also be understood that the procedures set forth above need to be carried out. performed in any telecommunications system that uses a packet radio communication service inserted within a TLMN circuit-switched, traditional environment. As seen in Figure 7 (along with Figures 2, 3), there is a need to connect a large number of ISP Internet service providers to a GPRS network (ie to the GGSN thereof) to attract as many customers. as possible. In Figure 7, still an intra-TLMN main network [sic] connected to a GPRS network (or a GGSN node thereof, as seen in Figure 3) is considered as an ISP Internet service provider, due to technically there are no differences, because in terms of interconnection both are connected to the GGSN. As already explained, based on the activation procedure of the PDP context, the current GPRS standard (GSM 03.60) already allows the possibility of interconnecting the GGSM node to a large number of internal networks (the ISPs). A subscriber can have a subscription (usually in the HLR to one or more of these networks, for example, subscribing to his company's Internet (in Figure 7: corporate network as ERINET in Ericsson) or to a data network in packages (in Figure 7: X.25 PDN) and one or more Internet service providers (in Figure 7: local ISP, ISP1, ISP2) During the log-on procedure and activation of the PP context, the SGSN will negotiate with the GGSN the PDP context for a specific network, however, with the activation of the service, the subscriber station (ie, the mobile station) does not have the possibility to flexibly indicate to the GPRS network with which of its subscribed IPSs Therefore, the objective of the present invention is to: - offer a method, a switching device, a telecommunications system and a terminal station that allow a GPRS subscriber a more flexible use of various external networks connected to the GPRS This obj The solution is solved by a method for data communications between a first terminal station of a mobile telecommunications radio network and a second terminal station of a packet data communications network, consisting of the following steps: a) sending a parameter network indication indicating a predetermined packet data communications network from the first terminal station to a switching device of the mobile telecommunications radio network to which a plurality of packet data communications networks are connected; b) selecting an access means in the switch device that provides access to the packet data communications network indicated by the network indication parameter; c) activating the selected access means to access a switching device of the indicated packet data communications network. This objective is further solved by a switching device for providing data communications between a first station, terminal of a mobile telecommunications radio network and a second terminal station of a plurality of packet data communications networks connected thereto, which it comprises: a) a receiving means for receiving a network indication parameter, indicating a predetermined packet data communications network from the first terminal station; b) a plurality of access means each providing an access to one of the connected packet data communications networks; c) a selection means for selecting an access means according to the received network indication parameter; and d) a control means for activating the selected access means to access a switching device of the indicated packet data communication network. This objective is also solved by a telecommunications system for providing packet data communications between a first and a second terminal station thereof, consisting of: a) at least one mobile radio communications network to which the first terminal station is connected; and b) a plurality of packet data communications networks, the second terminal station being connected to one of the networks of. data communications in packages; and c) the communication networks being connected to a switching device consisting of: cl) a receiving means for receiving an indication parameter of the network, indicating a predetermined packet data communication network from the first terminal station through of the mobile radio communications network; c2) a plurality of access means each providing an access respectively to one of the data communications networks in connected packets; c3) a selection means for selecting an access means according to the received network indication parameter; and c4) a control means for activating the selected access means to access a switch device of the indicated packet data communications network. This objective is further solved by a terminal terminal of a mobile telecommunications radio network for packet data communications to a predetermined terminal station of a packet data communications network, consisting of: a) a memory means of the indication parameter of the network for storing a plurality of network indication parameters respectively, corresponding to a packet data communications network connected to the mobile telecommunications radio network through a switching device; b) a selection means for selecting a network indication parameter from the memory means indicating a packet data communications network to / from which the terminal station will transmit / receive data in packets; and c) a network request means for sending the indication parameter of the selected network to the switching device to request a connection to the packet data communications system indicated by the network indication parameter.

According to the invention, a network indication parameter is transferred to the SGSN, which indicates the desired network, preferably during the activation procedure of the PDP context. The network indication parameter may be of a PDP type negotiated for the PDP context in the PDP context activation procedure. Thus, while the GPRS subscriber station was traditionally limited to relying on the SGSN to negotiate the appropriate network, according to the invention, any desired network can be pre-specified during the activation of the PDP context or the log-on procedure. Other advantageous embodiments and improvements of the invention can be obtained from the dependent claims. Hereinafter, the embodiments of the invention will be described with reference to the accompanying drawings. In the drawings, the same or similar reference numbers designate the same elements or steps or the like.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the basic concept of a General Packet Radio Service (GPRS, General Service of Radio Communication in Packages); Figure 2 shows the basic interconnection of nodes and networks in the GPRS system of Figure 1; Figure 3 shows the interconnection of intra-and inter-PLMN main networks connected to the nodes of the GPRS system in Figure 1, 2; Figure 4 shows the possibilities of a packet transmission between a GPRS mobile station and a host when the mobile station requests the transmission (Pl), when the host requests the transmission (P2) and when the mobile station has passed into the network of another GPRS operator (P3); Figure 5 shows a normal log-on procedure (start of assignment) of a GPRS mobile station to the gate GSN of the GPRS system shown in the Figures 1 to 4; Figure 6 shows a context activation procedure Traditional PDP for establishing the parameter table of PDP contexts in order to establish a tunnel between the mobile station MS of the GPRS and the packet data network; Figure 7 shows an overview of the different networks (providers of Internet services, corporate networks and X.25 PDN) connected to a system GPRS; Figure 8 shows a block diagram of a telecommunications system, a PLMN-SW switch device and a GPRS-MS terminal station according to the invention; Figure 9 shows a method according to the invention for selecting a packet data communications network according to an indication parameter of the NIP network sent from the terminal station PLMN; Figure 10 shows the mapping of the network indication parameters and the identification parameters for Iestablish an IP communication tunnel between a GPRS-MS / host station and a DHCP server of an ISP Internet service provider using a PDP type parameter; Figure 11 shows a context activation procedure PDP using a PDP type parameter to select a specific packet data communications network; and Figure 12 shows a modality of the NPI network indication parameter [sic].

PRINCIPLES OF THE INVENTION Figure 8 shows a general overview of the telecommunications system according to the invention. Figure 8 incorporates all the interconnection and devices that have already been shown in Figures 1 to 4, and in particular in Figure 7. Therefore, all the descriptions made in the foregoing for these interconnections and devices equally apply well to the interconnection and devices of Figure 8. For the purposes of the present invention, the mobile switching center / visitor location register MS / VLR, the residence location register HLR / SP of the mobile radio network PLMN ( for example, the PLMN A, PLMN B in Figure 3) as well as the support nodes of the GPRS SGSN servers and the support nodes of the GGSN gate .GPRS (GGSN1, GGSN2 ...) serving as a means of access form a general PLMN-S switching device for a mobile radio communications network supporting a general GPRS system. As also illustrated in Figure 1, of course the GPRS support nodes GSN can be located in the same PLMN or in different PLMN. As explained with reference to Figure 2 and Figure 1, each GGSN is provided to be connected to a respective packet data communications network, i.e., an Internet IN, a corporate network PDN2 (for example, an Intra-Network such as ERINET) or an X.25 network PDN PDNI . The interconnection between each access means (i.e., GGSN) is made through a tunnel or link to a respective switch device PDN-SW of the packet data communications network PDNl, PDN2, IN respectively. As illustrated in Figure 8, a connection between the PLMN supporting, the GPRS and the Internet IN can be made through a plurality of ISP1 Internet service providers., ISP2, ISP3, each containing a respective switching device PDN-SW. Therefore, according to the invention, a plurality of packet data communications networks supporting packet data transmission can be connected to a PLMN supporting GPRS through the PLMN-SW switching device, in particular by the GGSN access means. / 7AS. The selection by the GPRS subscriber of a plurality of packet data communications networks is applicable to mobile radio networks supporting GPRS and having connections to multiple packet data communications networks (Internet service providers / packet data communication network). As shown in Figure 8, a PLMN supporting GPRS is connected to multiple ISP Internet service providers by the Internet IN (for example, using IP-TUN IP tunnels) or by dedicated connections PI, P2. Although the technical realization of the interfaces and, in fact, of the data communications networks in interconnected packets is different at the point of interconnection, with respect to the need for packet data transmission, there is no difference if the external network of the PLM? is an IP (Internet Protocol) based on the Internet service provider (ISP) or an IP based corporate network PDN2 or a packet data network based on X.25 PDNI. For example, the interconnection point (the interface) Gi of an IP-based packet data communications network PDNl is the access server AS within the GPRS gateway support node GGSN (within the respective access means of the device). PLMN-SW switch). Therefore, it should be understood that in Figure 8 any kind of packet data communications network can be interconnected to a respective GGSN - as long as it supports a data protocol in PDP packets, for example, IP or X.25. . As also illustrated in Figure 8, even the Internet service providers themselves ISP1, ISP2, ISP2 [sic] are considered as packet data communication networks containing a respective PDN-SW switching device. A plurality of PTE terminal stations are connected to the respective packet data communications networks PDN1, PDN2, IN. On the other hand, the GPRS-MS terminal stations of the PLMN supporting GPRS communicate with a support node of the GPRS SGSN server of the switching device PLMN-SW, as already shown, in general, in Figures 1, 2. Tstation GPRS-MS terminal may be the mobile stations of the PLMN supporting GPRS, for example, a mobile station class A, B, C (see Figure 2) or any other user application supporting IP-based packet data transmission. Although Figure 8 only shows a PLMN supporting GPRS, it should be understood that, from Figure 3, that also several PLMN (PLMN A, PLMN B) each containing a switching device similar to the PLMN-SW switching device with the SGSN and GGSN may be provided along with other intranets or data networks in packets or interconnection networks. Thus, the configuration in Figure 8 should be seen completely analogous in Figure 3, where a plurality of packet data communications networks. (each one including a respective switching device PDN-SW) are interconnected to a switching device PLMN-SW or a PLMN supporting GPRS. When the PDN2 intranets or the data networks in additional PDN1 packets are available, the communication link is provided through separate connections PI, P2, while the interconnection to the ISP Internet service providers is made through the Tunnels of the Internet protocol IP-TUN. The mobile radio communication system PLMN is preferably a network of the GSM-based radio system such as a DI or D2 network including a General Radio Service System in GPRS Packets and the PDNl, PDN2 packet data transmission systems, IN comprises a network based on the IN network and / or a General Radio Service in GPRS Packets based on the Internet protocol of the company PDN2 and / or an X.25 PDNl network and / or an Internet protocol.

NIP network indication parameters As shown in FIG. 8, the GPRS-MS terminal of the mobile radio telecommunications network PLMN contains a means of memory of the network indication parameters? IP-MEM to store a plurality of IP network indication parameters respectively, corresponding to a packet data communications network connectable to the mobile radio telecommunications network through the PLM switch device? -SW. SEL selection means for selecting an IP network indication parameter from the memory medium? IP-MEM is provided at the GPRS-MS terminal station to indicate a packet data communications network to / from which the station terminal wants to transmit / receive data in packets. A request means of the network? RM of the GPRS-MS terminal station is provided to send the indication parameter of the selected IP network to the PLM? -SW switch device in order to request a connection to the data communication system. in packages indicated by the indication parameter of the NIP network. In addition to the devices already described in FIGS. 1 to 4, the PLMN-SW switching device contains a NIP-RC receiving means for receiving the NIP network indication parameter indicating the predetermined packet data communication network from ( first) GPRS-MS terminal of the PLMN. The SGSN in communication with the GPRS-MS terminal station contains a selection means SEL for selecting a GGSN / AS access means according to the indication parameter of the received PIN network. As already explained, each GGSN serves as a means of access to provide access to one of the connected packet data communications networks PDNl, PDN2, IN. Within each access means there is an AC control means for activating the access means for accessing a PDN-SW switch device of the indicated packet data communications network, that is, to establish a connection with the ( second) respective PTE terminal station of the desired packet data communications network. A memory means of the HLR subscription, for example, provided in the residence location register HLR stores subscription parameters SP indicating a subscription of the GPRS-MS terminal station to the data communications networks in predetermined packets. The means of checking the SCM subscription provided in the SGSN compares the indication parameter of the received NIP network with the subscription parameters SP stored in the memory means of the HLR subscription. The control means AC only activates a selected access means AS to provide an access to the desired switching device PDN-SW of the respective packet data communications network, when the indication parameter of the network PIN received from the GPRS terminal -MS matches one of the parameters of the SP subscription in the memory medium of the HLR subscription. Of course, when the respective terminal stations have correct access to all possible packet data communications networks, it is not necessary to provide the means of checking the SCM subscription and the memory medium of the HLR subscription since the PLMN switch device -SW will always provide the packet data communications network indicated by the network indication parameter, respectively sent.

Selection of packet data networks Figure 9 shows a method for data communications between a (first) mobile terminal GPRS-MS of the mobile radio network PLMN and a (second) terminal station PTE of a packet data communications network PDNl, PDN2 IN, according to the invention. In Figure 9, a PLMN terminal station (a GPRS-MS mobile station or any end user application) selects an NIP network indication parameter from the NIP-MEM memory medium. Preferably, the NIP network indication parameter not only indicates the desired packet-data communications network but also the type of session that the end station intends to perform with the second PTE station of the data communications network in packages. For example, the NIP network indication parameter can indicate the intra-network (corporate network) PDN2, that is, NIP = ERINET for a DELTA access. In the same way, the NIP network indication parameter can indicate AoL for an email session. All these network indication parameters can be made through the PDP type parameter as will be explained later (details of the PDP type context are explained above and are referenced by the GSM 03.60 proposed version, document 2.0.0 by ETSI). When the desired network indication parameter (and possibly the communication type) PIN has been selected from the memory medium of the NIP-MEM network indication parameter, the request means of the NRM network sends the PIN in step STl to the switch means PLMN-SW, preferably to the SGSN. Assuming that the first GPRS-MS terminal does not automatically have access to all packet data communications networks, the SGSN will check whether the indicated network, that is, the chosen packet data communications network, is subscribed or do not. Therefore, the checking means of the SCM subscription compares the indication parameter of the received network PIN with the subscription parameters SP stored in the subscription memory means HLR. In step ST2, a rejection indication may be transmitted to the first terminal station in case an invalid SP subscription parameter is found in the memory medium of the HLR subscription, which would match the indication parameter of the received network PIN. . Such a rejection procedure, using a PDP type parameter can, for example, be established through a PDP rejection procedure as described in GSM 03.60 Proposed version 2.0.0. If the GPRS-MS terminal has a valid subscription to the packet data communications network indicated by the NIP network indication parameter, the SEL selection means in step ST3 selects a suitable GGSN to which the communications network of data in packages is connected. That is, the SGSN will select an address for the appropriate GGSN in step ST3. An AC control means in the selected GGSN (the access means) selects a suitable AS access server to form a connection to the desired PDN-SW switch device of the packet data communications network. When the appropriate access server included in the GGSN has been selected and activated, the GGSN establishes a connection with the PDN-SW switching device (for example, the Internet service provider IPS) in step ST4, for example, the GGSN will use a RADIUS server towards ISP1. The ISP or respective PDN-SW switching device in the packet data communications network then establishes a connection to the desired packet terminal station PTE in step ST6. Before carrying out communication between the PLMN terminal station and the PDN PTE terminal station, it is possible to return the confirmation messages as indicated in step ST6. When using the selection and transmission of a specific NIP parameter indicating the desired packet data communications network, any of the data communications networks in packets PDN1, PDN2, IN (or the providers ISP3, ISP2, ISP1 respectively thereof) can be selected for a packet data communication between the two terminals GPRS-MS, PTE. Thus, it is possible to connect a large number of IPS to a GPRS-GSM network since the subscription station [sic] has the possibility to indicate to the GPRS network which of the subscribed IPS wishes to connect its session. As will be appreciated, any kind of indication parameter of the NIP network can be selected and sent to the PLMN-SW switching device of the PLMNs that support GPRS. Preferably, an already existing (ie, standardized and agreed) parameter, ie, the "PDP type" parameter mentioned above) can be used for the same, in order to allow the GRPS-MS terminal station to select the specific ISP or the specific packet data communications network. The use of the PDP context and the PDP types are explained in the GSM 03.60 proposed version 2.0.0. That is, in the present invention, each network operator has the ability to map an ISP for a "PDP type" parameter and thereby indicate to which ISP or packet data communications network, the GPRS-MS end stations. Individuals can connect. The use of the "PDP type" parameter will be able to distinguish up to 64,000 ISPs (that is, 64,000 different classes of packet data communications networks). The "PDP type" parameter can be communicated to the PLM? -SW switch device during the PDP context activation procedure (see Figure 6) as will be explained later with reference to Figure 11.

Registration of a new subscription request In addition, it should be noted that the GPRS-MS terminal may comprise the request means to make a request to the PLMN-SW switching device of the PLMNs to request a subscription (right of access parameter) to a new packet data communications network supported by the PLMJM / 'GPRS system, to which the GPRS-MS terminal did not have access right before. When such an access request is received from the GPRS-MS terminal station, the SGSN may perform a registration routine to register an access right (subscription) to the network indicated in the HLR subscription memory means. The charge for the use of the packet data communications network can then be made through the SGSN or the GGSN responsible for the indicated packet data communications network. Otherwise, when the checking means of the SCM subscription receives an indication parameter of the NIP network from the GPRS-MS for which no record was found in the subscription memory means HLR, the subscription checking means can be not only perform a rejection procedure as in step ST2 in Figure 2, but the means of checking the subscription SCM can also execute a registration procedure to register a new subscription parameter in the subscription memory means HLR. In the registration procedure, the subscription checking means will ask whether the GPRS-MS wishes to subscribe to the packet data communications network indicated by the NIP network indication parameter, and if so, then the new registration it is registered as a valid subscription parameter in the HLR subscription subscription medium. During the registration procedure it is possible to perform other services, that is, the transmission of special advertising, special charges or other information that the operator of the indicated packet data communications network wishes to transmit to a new GPRS-MS terminal station. In this case, the SGSN and the GGSN can already make a communication to transmit this information from the PDN-SW switching device of the packet data communications network to the GPRS-MS. Although the above explanation was generally maintained for any packet data communications network, hereinafter, the embodiments of the invention will be described for the specific case of an ISP Internet service provider / selection of the data network in PDN packets, where4 the parameter of the PDN type will be used as an indication parameter of the NIP network.

Selection of the ISP / PDN using a PDP Co type parameter or indicated in Figure 10, certain requirements must be met at the GPRS / MS terminal station (or the host station), the PLMN-SW switching device and the ISP / PDN for connecting the GPRS-MS terminal station to an ISP (i.e., its respective PDN-SW switching device) through a GPRS system. 1. As explained above in detail, the GPRS / MS-Host Terminal Station must have a valid subscription to at least one PDP type provided by the PLMN switch device (operator) in the HLR residence location register (it is say, the half memory of the subscription parameter). That is, the SIM card of the subscriber stations needs to be valid 'for the respective packet data communications network. 2. For data communications networks (ISP) based on the' Internet protocol (IP), the terminal station (GPRS-MS or host) must also have an assigned DHCP authorization token (and preferably an encryption key) provided by the packet data communications network (ISP). That is, in addition to the network identification parameter (SP) valid in the HLR, the GPRS-MS terminal station preferably comprises an ID identification means for sending an identification parameter as the HCP authorization token (and preferably an encryption key) to the PDN-SW switching device of the communications network of data in desired ISP1 packets (Internet IN). This will indicate that the GPRS-MS can establish an appropriate communication protocol for the DHCP-server / RADIUS server of the desired network (DHCP = dynamic host configuration protocol). Only when a means of validating the ID-VAL identification in the switching device PDN-SW determines a correspondence between the received identification parameter and one of the plurality of identification parameters stored in an ID-MEM identification memory medium provided in the half switch PDN-SW, the means to establish the communication link TUN-LK set in communication link (or IP-TUN communication tunnel). Although the GPRS-MS host must have stored the DHCP authorization token and preferably the identity of the DHCP server (of the DHCP-server of the PDN-SW switching device of the desired packet data network) as well as the relationship between the type PDP and the desired ISP, corresponding information is available in the DHCP server-RADIUS server (the means of access in the data network in respective package) for the key resolution. Thus, the PDN-SW also contains the DHCP user identification and the DHCP authorization token as illustrated in Figure 10. Preferably, for ISPs with IP-based packet data communication networks, the means of access respective (DHCP server) in the switch device PDN-SW can be updated with the identity of the international mobile station (IMSI) as mobile station / host identification option (terminal station) ie, if the terminal station is a mobile station supporting GPRS (as a class A, B, C mobile station), the access server (DHCP server) of the PDN-SW packet data network switching device always receives the identity of the current international mobile station. The PLMN PLMN-SW switch device needs to establish a communication link or tunnel to the ISP, possibly through the firewall of ISs for RADIUS information (only for ISPs based on Internet protocol). The formation of the IP tunnel through the establishment of the communication link means that 'TUN-LK is performed through a tunnel management message exchange, ie the procedure in the PDP context as mentioned in proposed document TS 100960 VI .1. by the ETSI. All switching units and routing devices in the IP tunnel (path) between the GPRS-MS (host and the means of access (DHCP server of the ISP) must support IP muitiffusion to send DHCP broadcast messages (only for IP-based ISPs). That is, characteristics 1 to 5 or a part determine the data communication system in packages (ISP) that must be connected by a communication link to the GPRS-MS and, on the other hand, allow to dynamically configure a protocol with the host if the identification parameters (DHCP-id and ISP-id and DHCP-witness authorization) match those provided by the PDN-SW switch device (the DHCP-server). Therefore, as shown in Figure 10, the host GPRS-MS must provide the DHCP authorization token and, preferably, the identity of the DHCP server as well as the relationship between the desired ISP and the PDP type parameter. The HLR should provide the mapping of the IMSI-type PDP parameter and the GGSN / AS / (ISP) -id, ie, the selection of the appropriate GGSN and the access server AS corresponding to the desired packet data network. The GGSN must provide mapping of the IMSI / PDP type parameter to the IS / ISP data access server. Finally, the DHCP-server in the same way must store the identity of the DHCP client and the DHCP authorization token to allow a mutual recognition of the GPRS-MS / host and the selected switch device PDN-SW and the establishment of a configured protocol adequately for communication between these.

Selection of the access server using activation in the PDP-type context The differences between a conventional circuit-switched access to an ISP / PDN and the selection of the access server based on the PDP-type parameter in the activation of the PDP context in the SGSN they are particularly obvious when considering Figure 11. First, it should be understood that already in the accesses of traditional switch circuits to the ISP / PDN, the terminal station has the possibility to choose the desired ISP (Internet Service Provider) and the access server by means of the number of the party receiving the call. Different ISPs simply have different access numbers, so that different access servers like COMPUSERVE, T-ONLINE, etc. they can be selected by the terminal station simply by dialing the appropriate number. Even in a GSM circuit-switched Internet access function, the selection of the appropriate access server is made by sending the number of the party receiving the appropriate call (CPN). According to the invention, the server selection is Access in the PLMN-SW (that is, the appropriate access server in the GGSN) is based on the PDP type parameter in the activation of the PDP context in the SGSN, as already described extensively in Figure 9. Figure 11 it can be seen as an extension of the conventional PDP context activation procedure shown in Figure 6, known from the proposed GSM documents TS100960 1.1.0 and GSM 03.60 proposed version 2.0.0 mentioned above. Therefore, the procedure in Figure 11 should be seen in the context of the general PDP context activation procedure of Figure 6. In step Sil, a request message activating the PDP context is sent from the first terminal station (host / GPRS-MS) to the support node GPRS server SGSN. Step Sil corresponds to step Sl in Figure 6, however, it contains a list of different parameters as indicated in Figure 11. In addition to other parameters already commonly required in the PDP context request in step Sl of Figure 6 , the request message activating the PDP context in step Sil of Figure 11 contains the PIN indication parameter, namely, the parameter w < PDP-type (< -> AS) ". In the parentheses < - > the selection means SEL of the GPRS-MS terminal inserts the indication of the selected network from the indication memory of the NRM network Thus < - > indicates "X.25 PDN, ERINET, ISP1, ISP2, ISP3" and all the network identification parameter, for example, the type PDP (X.25 AS) then indicates the request of the X.25 network PDN or more specifically, the AS server of the X.25 network .. Preferably, the PDP context request contains the normal MS-ID parameters (identity of the mobile station), QoS (quality of service requested) and the NSAPI (Identifier of the Access Point of Service in the Network Layer). Step S12 corresponds to step S2 in Figure 6. In step Sil ', the SGSN obtains the address of the appropriate GGSN of the GGSN serving the desired packet data network (see for example Figure 2). Of course, before continuing with step Sil ', the SGSN checks the PIN against subscriptions in the HLR. There are two possibilities in the way that the SGSN deduces the GGSN address in step Sil '. The address of the stored GGSN or the address of the GGSN obtained from the type PDP (and the AS) required is used. After step Sil ', the SGSN the GGSN to which the request must be sent to create PDP context in step S31. In addition to the normal parameters of the MS-ID and the neg.QoS (negotiated quality of service that has been agreed between the first terminal station and the SGSN), the create PDP context request of the inventive contains the parameter "TEPI PDN-type (< - > AS) ". This now contains the terminal point identifier TEPI indicating the identification of the terminal identification access point TE (GPRS-MS). In step S31 ', the GGSN receiving the request message create context PDP maps the PDP type to an AS access server identity. That is, the GGSN for example recognizes that the access server AS dedicated to the X.25 PDN needs to be activated due to the content of the parameter of the PDP type. The GGSN is the final connection point of the PLMN that supports GPRS and thus establishes a connection to the second terminal station (the switching device of the ISP-PDN PDN-SW and its connected terminal station PTE). Therefore, in step S31 'the tunneling protocol of the GPRS GTP is established to construct the path or the IP tunnel by means of the establishment of the communication link provided in the GGSN (see the IP tunnel of Figure 10). At the end of step S31 'the PDP context is activated. Therefore, in step S31"the response to create PDP context is sent to the SGSN from the GGSN." The PDP context creation response now contains, in addition to the parameters of step S31, the protocol BB and the TEPI of the terminal station PTE In step S31"'the tunneling protocol of the GPRS GTP is established, the LLC logical link control is established in the ABM mode and the PDP context is activated.

In step S41 the acceptance message activating PDP context is transferred to the first terminal station from the SGSN. Since the SGSN knows which first # terminal station has to send the request message activate PDP context in step Sil, the acceptance message activate context PDP in step S41 does not contain the TEPI information.

It contains the MS-ID, the requested QoS, the negotiated QoS and the PDP type (< - > AS) of the network identification parameter.

The situation after step S41 corresponds to the acknowledgment or acknowledgment message in step ST6 in Figure 9 at the PLMN terminus. As explained with reference to Figure 9 above, after step S41 the bearer service is established, since the packet data network is selected by the desired Internet service provider and a suitable protocol and servers have been selected. . In step S41 'the control of the LLC logical link is established in the ABM mode. An Internet Protocol (IP) bearer is established between the host / GPRS-MS and the selected AS access server even if the host / GPRS-MS does not have an IP address. Now, IP DHCP packets can be sent from the GPRS-MS / host via the GPRS bearer to the desired AS access server in the GGSN which retransmits the packets to the appropriate PDN-SW switching device in the packet data network or Internet service provider.

It should be noted that the course of the activation procedure of the PDP context in Figure 11 applies to the establishment of IP tunnels for Internet service providers as well as to the establishment of communication links Pl, P2, P3, in general (as it is observed in Figure 4, 8, 10).

PDP type parameter mode As shown in Figure 12, preferably, the PDP type parameter is a 16 bit parameter whose interpretation is as follows: 0 IP, default interworking network (for example, the main inter-network) PLMN shown in Figure 3, Figure 4); 1 X.25, default interworking network; 2-99 reserved to be interpreted as "IP, default interworking network" by this version of the protocol; 100-12000 specific interworking network of the PLMN; 12001-64k reserved for future use. Of course other interpretations of the PDP parameter of 16 bits can be made and the above definition only applies to a preferred embodiment of the invention. The PDP type parameter can also have different length instead of 16 bits. In Figure 12A, the default interworking network has been specified in the PDP type parameter.

Selection of the ISP (Internet Service Providers) As already explained, the normal case in a circuit-switched access is that the selection of the ISP (Internet service provider) is made through the access server and is based on the user identity (user-id) received together with the DHCP authorization as an identification parameter. Therefore, the identification parameter indicates the domain name of the ISP. For example, authorization from HCP can normally be, for example, www.ericsson.se. The last part of this DHCP authorization indicates the domain name of the ISP, in this case? Ericsson.se. "As a rule, the AS access server will check the domain name of the ISP with its RADIUS configuration data to determine the ISP tunnel (ie, the communication link) As already explained above with reference to Figure 11 , in accordance with the present invention, the selection of the ISP in a GPRS environment is done differently, as also indicated in Figure 12, for "PLMN-specific interworking networks", the network indication parameter, that is, the PDP type parameter, can preferably be interpreted as consisting of two subfields: a first indication field NPI-1 containing the "identity of the access server" and a second field of "indication NPI-2 contains the" identity of the Internet service provider. "As already explained, the special subscription parameter (data) is stored in the memory of the subscription parameter HLR. Therefore, according to another embodiment of the invention, the access possibilities for the specific GPRS-MS can be limited to only a sub-number of possible ISPs. Preferably, the HLR subscription data is established by the PLMN-SW switching device to define closed user groups for company local area networks (LANs), so as to limit an access of external terminal stations to access to a Company LAN, that is, avoiding a massive load on the RADIUS server of the data network in specific packages of a company. Each switching device of the PLMN (operator) defines the PDP type parameter and identifies the ISP Internet service provider, for example, (see Figure 12a): "100 = AoL", "Í01 = COMPUSERVE", "102 = ERINET "," 103 = T-ONLINE "and so on.

Thus, while the PDP type parameter contains the same indication or identity for the desired access server, only an eventual connection is made to the desired packet data communications network when the identity of the ISP also matches that of the data contained therein. of the subscription in the HLR. Thus, by using two separate fields in the PDP type parameter, a two-stage grouping of the terminal stations can be obtained. As already explained, the use of an already existing parameter (that is, standardized and established), that is, the PDP type parameter allows the terminal station of the PLMN that supports GPRS to select a specific ISP. All operators in the network have the ability to map an ISP for a "PDP type parameter" and can thus indicate the ISP with which terminal stations can be connected. When using a PDP type parameter of 16 bits up to 64,000 ISP can be connected. Thus, a large number of ISPs (Internet service providers) may be connected to a GPRS network allowing a more flexible use of Internet service providers for the GPRS network.

PDP parameters modified for use of various networks in parallel According to another embodiment of the invention, the PDP type parameter can also be modified so that the GPRS terminal can request access to two or more data communication networks in PDNl, PDN2 packages simultaneously. In this case, the PDP type parameter will contain two inputs, each defined as in Figure 11. The SGSN will then select two or more suitable GGSNs and two communication links will be established simultaneously. Due to the packet nature of the PLMN supporting a GPRS system, the GPRS-MS terminal can therefore communicate simultaneously with two PTE terminal stations of two separate packet data communications networks that have been requested through the transmission of a PDP type parameter, in two stages, specific.

INDUSTRIAL APPLICABILITY As already explained, the method, switching device, telecommunications system and terminal station according to the invention allows users of a PLMN network supporting GPRS to allow uploads to an arbitrary packet data network, desired, namely to use a number of different Internet service providers, cooperating networks, etc. The invention can be applied to any PLMN system that supports characteristics of a packet radio communications service and is thus not limited to the particular use in a GSM system supporting GPRS in accordance with the ETSI standards present. Furthermore, the invention is not limited to the specific, preferred embodiments described herein and the person skilled in the art can make modifications and variations of the invention within the scope of the attached clauses. In these clauses, the reference numbers only serve for purposes of clarity and not to limit the scope of these claims.

Claims (39)

1. CLAIMS A method for data communications between a first terminal station (TE, MT; GPRS-MS) of a mobile telecommunications radio network (PLMN) and a second terminal station (PTE) of a packet data communications network (PDNl, PDN2, IN), is characterized by the following steps: a) sending (NRM, SEL, STl, Sil) a network indication parameter (NIP, PDP-type (< - > AS) indicating a communications network of data in predetermined packets (PDNl, PDN2, IN) from the first terminal station to a switching device (GSN, SGSN, GGSN, PLMN-SW) of the mobile telecommunications radio network (PLMN) to which a plurality of communications networks data in packets (PDNl, PDN2, IN) are connected, b) select (SEL, ST3, Sil ', S31) an access medium (GGSN / AS) in the switching device (PLMN-SW) providing an access to the packet data communications network indicated by the network indication parameter (PIN); and c) activating (AC, ST4, S31 ') the selected access means (AS) to access a switching device (PDN-SW) of the indicated packet data communications network (PDNl, PDN2, IN). The method according to claim 1, characterized in that after receiving the network indication parameter (NIP) the network indication parameter (PIN) is compared (SGSN, SCM, ST3) with the subscription parameters ( SP) stored in a subscription memory medium (HLR) and the selection and activation of the access medium (GGSN / AS) is only carried out when the received network (NIP) indication parameter matches one of the parameters subscription (SP) in the subscription subscription medium (HLR). The method according to claim 1, characterized in that after the access means (AS) is activated, a communication link (Pl, P2, P3, IP-TUN) is established between (ST4, ST5, S31 ') between the first and second terminal stations (GPRS-MS; PTE) by a means for establishing the communication link (TUN-LK) through the switching device (PLM? -SW) of the mobile telecommunications radio network (PLM?) and the switch device (PD? -SW) of the selected packet data communications network (PD?). The method according to claim 3, characterized in that the first terminal station (GPRS-MS) of the mobile radio communications system (PLMN) sends an identification parameter (DHCP-id) to the switching device (PDN-SW) of the system of packet data communications (PDNl, PDN2, IN) and the means for establishing the communication link (TUN-LK) establishes (ST4, ST45, S31 ') a communication link only when a validation means (ID-VAL) ) provided in the switch means (PD? -SW) of the packet data communications network (I?) determines a correspondence between the received identification parameter (DHCP-id) and one of a plurality of identification parameters (DHCP). -id) stored in a means of identification memory (ID-MEM) provided in the switch means (PD? -SW). The method according to claim 4, characterized in that the communication link (IP-TUN) is established between the two terminal stations by means of the switching device (PLM? -SW) of the mobile radio communication system (PLM?) And a means (DHCP-SERV) of the switching device (PD? -SW) of the packet data communications system (PD? 1, PD? 2, I?). The method according to claim 1, characterized in that the network identification parameter (NIP) also indicates the type of data communication (email, DELTA). 7. The method according to claim 1, characterized in that the mobile radio communications system (PLMN) is a radio communications network based on GSM, such as a DI or D2 network including a general service of radio communications in packets. (GPRS) and packet data communications networks (PD? 1, PD? 2, I?) Comprises an intranet of the company (PD? 2) and / or an X.25 network (PD? 1) and / or a network based on the Internet protocol (I?) And / or a network based on general radio communications services in packets (GPRS). The method according to claim 1 and 7, characterized in that the network indication parameter (? IP) is a PDP type parameter that is transmitted to the switch device (PLM? -SW) of the radio communications network. mobile (PLM?) when performing a PDP context activation procedure (Sil, S12, Sil ', S31, S31', S31", S31" ', S41'; Sl, S2, S3 ', S3", S4) in the GPRS system 9. The method according to claim 5 and 7, characterized in that the switching device (PDN-SW) of the packet data communications system ( IN) is an Internet service provider (ISP1, ISP2) and the means of access (DHCP-SERV) is an HCP server of the Internet service providers (ISP1, ISP2) The method according to claim 4 and 9, characterized in that the identification parameter (DHCP-id) is sent to the DHCP-server (DHCP-SERV) of the Internet service provider (IS1, IS2) A switching device (GSN, SGSN, GGSN, PLMN- SW) to provide data communications between a first terminal station (TE, MT, GPRS-MS) of a mobile telecommunications radio network (PLMN) and a second terminal station (PTE) of one of a plurality of data communications networks in packages (PDNl, PDN2, IN) connected to it, is characterized by: a) a means of reception (NIP-RC) to receive a network indication parameter (PIN, PDP-type (< - > AS)) indicating a predetermined packet data communications network (PDNl, PDN2, IN) from the first terminal station; b) a plurality of access means (GGSN / AS) each providing an access to one of the connected packet data communications networks (PDNl, PDN2, IN); c) a selection means (SEL) for selecting an access means (GGSN / AS) according to the received network indication parameter (PIN); and d) a control means (AC) for activating the selected access means (AS) for accessing a switch device PDN-SW) of the indicated packet data communications network (PDNl, PDN2, IN). The switch device according to claim 11, characterized by a subscription memory means (HLR) for storing the subscription parameters (SP) indicating a subscription of the terminal stations (GPRS-MS; PTE) to the network of data communications in predetermined packets (PDÑ1, PDN2, IN); and a subscription checking means (SCM, SGSN) for comparing the received network indication parameter (PIN) with the subscription parameters (SP) stored in the subscription memory medium (HLR); wherein the control means (AC) activates a selected access means (AS) only when the received parameter matches (NIP) with one of the parameters (SP) in the subscription memory medium (HLR). 13. The switching device according to claim 11, characterized in that a means for establishing the communication link (TUN-LIN) for establishing a communication link (Pl, P2, P3, IP-TUN) between the first and the second terminal station through the mobile telecommunications radio network (PLMN) and the switch device (PDN-SW) of the selected packet data communications network (PDNl, PDN2, IN). The switch device according to claim 13, characterized in that the means for establishing the communication link (TUN-LK) establishes a communication link only when a validation means (ID-VAL) provided in the switching means ( PD? -SW) of the packet data communications network (I?) Determines a correspondence between an identification parameter (DHCP-id) sent from the first terminal station (GPRS-MS) and one of a plurality of parameters of identification (DHCP-id) stored in a means of identification memory (ID-MEM) provided in the switch means (PD? -SW). 15. The switch device according to claim 14, characterized in that the means for establishing the communication link establishes the communication link (IP-TUN) between the two terminal stations through the switching device (PLMN-SW) of the system. of mobile radio communications (PLMN) and a means of access (DHCP-SERV) of the switching device (DHCP-SERV) of the selected packet data communications system (IN). 16. The switch device according to claim 11, characterized in that the network identification parameter (PIN) also indicates the type of data communication (e-mail); DELTA). 17. The switch device according to claim 11, characterized in that the mobile radio communications system (PLMN) is a radio communications network based on GSM such as a DI or D2 network, including a General Radio Communications Services in Packages (GPRS) and packet data communications networks PDNl, PDN2, IN) comprise a company intranet (PDN2) and / or an X.25 network (PDNl) and / or a network based on the Internet protocol ( IN) and / or a network based on the general service of radio communications in packets (GPRS). The switching device according to claim 11 and 12, characterized in that the receiving means (NIP-RC) and the selection means (SEL) are provided in a support node of the GPRS server (SGSN) of a service system General Radio Packet Communications (GPRS) serving the first terminal station and the access medium (AS) in a GPRS gateway support node (GGSN) connected to the supporting GPRS server node (SGSN) and the communications network of data in selected packages (for example IN), wherein the selecting means (SEL) selects a gate GPRS support node (GGSN) connected to the indicated packet data communications network; and the subscription subscription medium (HLR) is a Home Location Register (HLR) Residence Location Register) of the mobile radio communications system, the subscription verification means (SCM, SGSN) is provided on the support node of the GPRS server (SGSN) and the access medium (AS) is an access server (AS) provided in the GPRS gateway support node (GGSN). The switching device according to claim 11 and 17, characterized in that the switching device (PDN-SW) of the packet data communications (IN) system is an Internet service provider (ISP1, ISP2) and the parameter of Network indication (PIN) contains a first field (NIP-1) indicating the identity of the access server (AS-Id) and a second field (NIP-2) indicating the identity of the Internet service provider (ISP-Id). The switching device according to claim 15 and 19, characterized in that the access means (DHCP-SERV) is a DHCP-server of the Internet service provider (ISP1, ISP2). A telecommunications system (GPRS, GSM) for providing packet data communications between a first and a second terminal station (TE, MT, GPRS-MS; PTE) thereof consists of: a) at least one mobile radio communications network (PLMN A, PLMN B) to which the first terminal station (MS) is connected; and b) a plurality of packet data communications networks (PDNl, PDN2, IN), the second terminal station (PTE) being connected to one of the packet data communications networks (PDNl, PDN2 IN); and c) the communication networks being connected to a switching device (PLMN-SW) characterized in that the switching device (PLMN-SW) comprises: cl) a receiving means (NIP-RC) for receiving a network indication parameter ( NIP, PDP-type (< - > AS), indicating a predetermined packet data communications network (PDNl, PDN2, IN) from the first terminal station (GPRS-MS) through the mobile radio communications network (PLMN); c2) a plurality of access means (GGSN / AS) each providing an access respectively to one of the data communications networks in connected packets (PDNl, PDN2, IN); c3) a selection means (SEL) for selecting an access means (GGSN / AS) according to the indication parameter of the received network (NIP); and c4) a control means (AS) for activating the selected access means (GGSN / AS) to access a switching device (PDN-SW) of the indicated packet data communications network (PDNl, PDN2, IN ). The system according to claim 21, is characterized by the switching device (PLMN-SW) comprising: a subscription memory means (HLR) for storing the subscription parameters (SP) indicating a subscription of the terminal stations (GPRS- MS; PTE) to the default of the packet data communications networks (PDNl, PDN2, IN); and a subscription checking means (SCM, SGSN) for comparing the indication parameter of the received network (SP) with the subscription parameters (NAP) stored in the subscription memory medium (HLR); wherein the control means (AC) activates a selected access means (AS) only when the received parameter (PIN) corresponds to one of the parameters (SP) in the subscription subscription medium (HLR). The system according to claim 21, characterized in that a means for establishing the communication link (TUN-LIN) for establishing a communication link (Pl, P2, P3, IP-TUN) between the first and the second terminal station through the switch device (PLMN-SW) of the mobile telecommunications radio network (PLMN) and the switch device (PDN-SW) of the selected packet data communications network (PDNl, PDN2, IN). The system according to claim 23, characterized in that the first terminal station (GPRS-MS) contains an identification means (ID) for sending an identification parameter (DHCP-id) to the switching means (PDN-SW) of the Packet data communications network (ID); and the means for establishing the communication link (TUN-LK) establishes a communication link only when a validation means (ID-VAL) provided in the switch means (PD? -SW) of the packet data communications network (I?) Determines a correspondence between an identification parameter (DHCP-id) sent from the first terminal station and one of a plurality of identification parameters (DHCP-id) stored in a means of identification memory (ID-MEM) provided in the switch medium (PD? -SW). The system according to claim 24, characterized in that the means for establishing the communication link establishes the communication link (IP-TU?) Between the two terminal stations through the switching device (PLM? -SW) of the communication system. mobile communications radio (PLM?) and a means of access (DHCP-SERV) of the switching device (DHCP-SERV) of the packet data communications (IN) system. The system according to claim 21, characterized in that the network identification parameter (NIP) also indicates the type of data communication (email, DELTA). The system according to claim 21, characterized in that the mobile radiocommunication system (PLMN) is a network of the radio system based on GSM such as a DI or D2 network including a General Packet Radiocommunication Service (GPRS) and the packet data transmission systems (PDNl, PDN2, IN) comprise a company intranet (PDN2) and / or an X.25 network (PDNl) and / or a network based on Internet protocol (IN) and / or a network based on general packet radio services (GPRS). The system according to claim 21 and 22, characterized in that the receiving means (NIP-RC) and the selection means (SEL) are provided in a server support node GPRS (SGSN) of a general service system of packet radio communications (GPRS) serving the first terminal station, and the access means (AS) is a GPRS gateway support node (GGSN) connected to the supporting GPRS server node (SGSN) and the data communication system in selected packets (e.g., IN), wherein the selecting means (SEL) selects a gate GPRS support node (GGSN) connected to the indicated packet data communications system; and the subscription subscription medium (HLR) is a Residence Location Register (HLR) of the mobile radiocommunication system, the subscription verification means (SCM, SGSN) is provided on the support node GPRS server (SGSN) and the access means (AS) is an access server (AS) provided in the gate GPRS support node (GGSN). 29. The system according to claim 21 and 28, characterized in that the switching device (PDN-SW) of the packet data communications (IN) system is an Internet service provider (ISP1, ISP2) and the parameter network indication (PIN) contains a first field (PIN-1) indicating the identity of the access server (AS-Id) and a second field (PIN-2) indicating the identity of the Internet service provider (ISP- Id). The system according to claim 25 and 27, characterized in that the access means (DHCP-SERV) is a DHCP-Server of the Internet service provider (ISPl, ISP2). A terminal station (GPRS-MS) of a mobile radio network (PLMN) for packet data communications to a predetermined terminal station (PTE) of a packet data communications network (PDNl, PDN2, IN), is characterized because: a) a memory means of the network indication parameters (NIP-MEM) .to store a plurality of network indication parameters (NIP) respectively, corresponding to a packet data communications network connected to the mobile radio telecommunications network through a switching device (GSN, SGSN, GGSN, PLMN- 'SW)); b) a selection means (SEL) for selecting a network indication parameter (NIP) from the memory medium (NIP-MEM) indicating a packet data communications network to / from which the terminal station transmits / receives data in packages; and c) a network request means (NRM, Sl) for sending the selected network indication parameter (NIP) to the switching device (GSN, SGSN, GGSN, PLMN-SW) to request a connection to the packet data communication system indicated by the network indication parameter (PIN). 32. The terminal station according to the claim 31, characterized in that the network request means (NRM) executes a procedure for establishing connection (S1-S4) to establish a communication path (IP-TUN, Pl, P2, P3) to the data communications network in packets (PDNl, PDN2, IN) in response to receipt of a confirmation from the switching device (PLMN-SW) that the terminal station has a right of access to the desired packet data communications system. 33. The terminal station according to claim 31 or 32, is characterized in that an identification means (ID) for sending an identification parameter (DHCP-id) to the switching device (PLMN-SW). 34. The terminal station according to claim 31, characterized in that the sent network indication parameter (NIP) also indicates the type of data communication (e-mail, DELTA). The terminal station according to claim 31, characterized in that the mobile radiocommunication system (PLMN) is a GSM-based radio system network such as a DI or D2 network and packet data transmission systems (PDNl). , PDN2, IN) comprises an intranet of a company (PDN2) and / or an X.25 network (PDNl) and / or a network based on Internet protocol (IN) and / or a network based on the general radiocommunication service in packages (GPRS). The terminal station according to claim 31 and 35, is characterized in that the network indication parameter (NIP) is a PDP type parameter and the network request means (NRM) transmits the parameter to the switching device (PLMN- SW) when performing a PDP context activation procedure (Sil, S12, Sil ', S31, S31', S31", S31" ', S41, S41'; Sl, S2, S3 ', S3", S4) in The GPRS system The terminal station according to claim 31 and 35, characterized in that the switching device (PDN-SW) of the packet data communications (IN) system is an Internet service provider (ISP1, ISP2) and the network indication parameter (NIP) contains a first field (NIP-1) indicating the identity of the access server (AS-Id) and a second field (NIP-2) indicating the identity of the Internet service provider (ISP-Id) 38. The switching device according to claim 11 and 17, is characterized in that the parameter network indication (NIP) is a PDP type parameter that is transmitted to the switch device (PLMN-SW) of the mobile radio network (PLMN) when a PDP context activation procedure is performed (Sil, S12, Sil ' , S31, S31 ', S31", S31"', S41, S41 '; Sl, S2, S3 ', S3", S4) in the GPRS system 39. A system device according to claim 21 and 27, characterized in that the network indication parameter (NIP) is a PDP type parameter that is transmitted to the switch device (PLMN-SW) of the mobile radio network (PLMN) when a PDP context activation procedure is performed (Sil, S12, Sil ', S31, S31', S31", S31 '", S41) , S41 '; Sl, S2, S3', S3", S4) in the GPRS system.