WO2011079861A1

WO2011079861A1 - Control of connection setup via different access networks

Info

Publication number: WO2011079861A1
Application number: PCT/EP2009/068012
Authority: WO
Inventors: Atte Markus Lansisalmi; Gyorgy Tamas Wolfner
Original assignee: Nokia Siemens Networks Oy
Priority date: 2009-12-30
Filing date: 2009-12-30
Publication date: 2011-07-07

Abstract

There is proposed a mechanism for controlling setup of a packet data network connection to a specified access point name via a gateway network element wherein different access networks are usable. When a request regarding a setup of a new packet data network connection to a specified access point name via the gateway network element is received, it is checked, based on the access network used for setting up the connection whether or not there is another connection to the specified access point name via the gateway network element via another different access network. If there is such a connection, the setup request is rejected. Otherwise, the setup of the connection via the gateway network element is allowed.

Description

DESCRIPTION

TITLE

Control of connection setup via different access networks

BACKGROUND OF THE INVENTION Field of the invention

The present invention relates to an apparatus, method and computer program product related to a control of a

connection setup via different access networks. In

particular, the present invention is related to a mechanism for controlling setup of a connection, such as a packet data network connection, to a specified destination, i.e. a specified access point name, via a gateway element when different access networks are usable. Related background Art

Prior art which is related to this technical field can e.g. be found by the technical specifications TS 23.401 (current version: 9.2.0) and TS 23.402 (current version 9.2.0) of the 3GPP.

The following meanings for the abbreviations used in this specification apply:

3GPP - 3^rd generation partnership project

AAA - Authentication, Authorization, and Accounting

AN - Access Network

APN - Access Point Name

ePDG - evolved Packet Data Gateway

EPC - Evolved Packet Core

EPS - Evolved Packet System

EUTRAN - Evolved Universal Terrestrial Radio Access Network

GERAN - GSM (Global System for Mobile Communications)

EDGE (Enhanced Data Rates for GSM Evolution)

Radio Access Network

HSS - Home Subscriber Server

IP - Internet Protocol

LTE - Long Term Evolution

MAG - Mobile Access Gateway

MME - Mobility Management Entity

PDN - Packet Data Network

PDN GW - Packet Data Network Gateway

SGSN - Serving GPRS Support Node

SGW - Serving Gateway

UE - User Equipment

UTRAN - UMTS Terrestrial Radio Access Network

WI - Work Item

WiMAX - Worldwide Interoperability for Microwave Access

In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN) , or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation

(3G) communication networks like the Universal Mobile

Telecommunications System (UMTS) , cellular 2nd generation

(2G) communication networks like the Global System for Mobile communications (GSM) , the General Packet Radio System (GPRS) , the Enhanced Data Rates for Global

Evolutions (EDGE) , or other wireless communication system, such as the Wireless Local Area Network (WLAN) or Worldwide Interoperability for Microwave Access (WiMAX) , took place all over the world. Various organizations, such as the 3^rd Generation Partnership Project (3GPP) , Telecoms & Internet converged Services & Protocols for Advanced Networks

(TISPAN) , the International Telecommunication Union (ITU) , 3^LCl Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards for telecommunication network and access environments. Generally, for properly establishing and handling a

communication connection between network elements such as a user equipment and another communication equipment, such as a database, a server, etc., one or more intermediate network elements, such as network control elements, support nodes, service nodes and interworking elements are involved which may belong to different communication networks.

One feature of several communication network solutions is that a subscriber (i.e. the UE) shall be enabled to

establish connections, such a packet data connections, via different types of access networks. For example, in the 3GPP EPS, the UE is enabled to be connected to the EPC via any type of 3GPP access networks (GERAN, UTRAN, E-UTRAN) and also via non-3GPP access networks, such as WiMAX or the like.

In other words, support is provided for a simultaneous use of 3GPP and non-3GPP access networks. One approach related to this issue is developed by the so-called MAPCON (Multi Access PDN Connectivity) WI described in 3GPP td S2-095969.

The target of the MAPCON WI is to allow the UE to establish PDN connection (s) over a 3GPP access and other PDN

connection ( s ) over a non-3GPP access simultaneously. More specifically, if the UE is under the coverage of a 3GPP access and one or more non-3GPP accesses, it shall be possible for a UE equipped with multiple network interfaces to communicate using multiple access systems simultaneously and to establish multiple PDN connections to different APNs via different access systems. One feature of this MAPCON approach is also to provide mechanisms to enable operator' s control on routing of active PDN connections across

available accesses. However, for ensuring proper functioning in such multiple access scenarios, it is necessary to consider some frame conditions. For example, in MAPCON WI, it has to be ensured that all PDN connections to the same APN use a single access network. However it is not specified how this is be fulfilled or controlled, i.e. which entity in the network shall enforce such a policy. SUMMARY OF THE INVENTION

Thus, it is an object of the invention to provide an apparatus, method and computer program product by means of which a new mechanism for controlling a setup of a

connection, such as a PDN connection, to a specified destination, i.e. a specified APN, via a gateway element is provided when different access networks are usable for the connection . This object is achieved by the measures defined in the attached claims.

According to an example of the proposed solution, there is provided, for example, a method comprising receiving a request regarding a setup of a new connection to a

specified destination via a gateway network element, detecting which access network is used for setting up the connection, wherein the detected access network is regarded as a first access network, and determining whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network, wherein the method further comprises rejecting, when the determining is positive, the setup request, or allowing, when the determining is negative, the setup of the connection via the gateway network element. Furthermore, according to an example of the proposed solution, there is provided, for example, an apparatus comprising a receiver configured to receive a request regarding a setup of a new connection to a specified destination via a gateway network element, a detector configured to detect which access network is used for setting up the connection, wherein the detected access network is regarded as a first access network, and a processor configured to determine whether or not there is another connection to the specified destination via the gateway network element, which other connection is

established via a second access network being different from the first access network, wherein the processor is further configured to reject, when the determination is positive, the setup request, or to allow, when the

determination is negative, the setup of the connection via the gateway network element. According to further refinements, there may be comprised one or more of the following features:

- when the setup request is rejected, a corresponding error cause indication may be sent towards the requesting side ;

- the connection may be a packet data network connection;

- the destination may be indicated by a specific access point name;

- the first access network may comprise one of an access network based on 3GPP or an access network not based on 3GPP, and the second access network may comprise the other one of the access network based on 3GPP or the access network not based on 3GPP;

- the process may be executed by or in the gateway network element; then, the gateway network element may be set to be selected for establishing a connection to the specified destination irrespective of which access network is used; - alternatively, the process may be executed by or in a network element allocated to the first access network and connected to the gateway network element, wherein further information regarding an establishment or a release of connections established via the gateway network element to the destination may be received, wherein the information may indicate also which access network is used, wherein the determination of whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network, may be based on the received information;

- further alternatively, the process may be executed by a home subscriber server system, wherein further information regarding an establishment or a release of connections established via the gateway network element to the

destination may be received, wherein the information may indicate also which access network is used, wherein the determination of whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network, may be based on the received information;

- the same gateway network element may be always selected for establishing a connection to the specified destination irrespective of which access network is used as the first access network.

In addition, according to an example of the proposed solution, there is provided, for example, a method

comprising receiving, when a user equipment is attached to an access network, subscription profile information

comprising identity information of at least one gateway network element, and selecting a specific gateway network element for an establishment of a new connection to a specified destination in accordance with the received identity information of the at least one gateway network element, wherein always the same gateway network element is selected for establishing a connection to the specified destination irrespective of which access network is used. Moreover, according to an example of the proposed solution, there is provided, for example, an apparatus comprising a receiver configured to receive, when a user equipment is attached to an access network, subscription profile

information comprising identity information of at least one gateway network element, and a selector configured to select a specific gateway network element for an

establishment of a new connection to a specified

destination in accordance with the received identity information of the at least one gateway network element, wherein the a selector is configured to always select the same gateway network element for establishing a connection to the specified destination irrespective of which access network is used. Furthermore, according to an example of the proposed solution, there is provided, for example, a method

comprising receiving and storing information comprising a gateway network element identity indicating a gateway network element used for a connection of a subscriber to a specified destination, and pushing information comprising the gateway identity to every access network to which the subscriber is attached, wherein the information is usable to always select the same gateway network element for establishing a connection to a specified destination irrespective of which access network is used.

In addition, according to an example of the proposed solution, there is provided, for example, an apparatus comprising means configured to receive and store

information comprising a gateway network element identity indicating a gateway network element used for a connection of a subscriber to a specified destination, and means configured to push information comprising the gateway identity to every access network to which the subscriber is attached, wherein the information is usable to always select the same gateway network element for establishing a connection to a specified destination irrespective of which access network is used.

Moreover, according to another example of the proposed solution, there is provided, for example, a computer program product for a computer, comprising software code portions for performing the steps of the above defined methods, when said product is run on the computer. The computer program product may comprise a computer-readable medium on which said software code portions are stored. Furthermore, the computer program product may be directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures. By virtue of the proposed solutions, it is possible to ensure a correct function or behavior of a communication network in a scenario of a simultaneous use of different access networks for different connections by enforcing frame conditions concerning the simultaneous establishment of plural connection over different access networks, such as 3GPP access networks and non-3GPP access networks. In particular, the implementation of a feature based on, for example, MAPCON is enabled by controlling the establishment of different connections to specific APNs via different networks in such a manner that the establishment of e.g.

PDN connections to the same APN is possible only via a single access network. In addition, it is possible to ensure that the same gateway network element, such as a PDN GW, is selected for a connection to the same (specific) destination (APN) from all access networks. Moreover, the connection control can be executed by different network elements, such as the gateway network element (e.g. PDN GW) itself, but also by network elements selecting the gatway network element, such as the MME, ePDN, MAG etc., or by the home subscriber server system. Furthermore, the proposed solutions is advantageous in that it can be implemented in existing communication networks with only a minimal amount of changes required.

The above and still further objects, features and

advantages of the invention will become more apparent upon referring to the description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a diagram illustrating an example of a

communication network in which examples of embodiments of the invention are implementable .

Fig. 2 shows a flow chart illustrating a procedure for controlling establishment of connections according to an example of an embodiment of the invention.

Fig. 3 shows a diagram illustrating a configuration of a network device executing a control of an establishment of connections according to an example of an embodiment of the invention .

Fig. 4 shows a flow chart illustrating a procedure for controlling establishment of connections according to an example of an embodiment of the invention.

Fig. 5 shows a diagram illustrating a configuration of a network device executing a control of an establishment of connections according to an example of an embodiment of the invention .

DESCRIPTION OF PREFERRED EMBODIMENTS In the following, examples and embodiments of the present invention are described with reference to the drawings. For illustrating the present invention, the examples and embodiments will be described in connection with a

communication system which may be based on a 3GPP LTE system where a UE is able to establish a connection, such as a PDN connection, via different access networks, such as 3GPP access networks and non-3GPP access networks. However, it is to be noted that the present invention is not limited to an application in such a system or environment but is also applicable in other communication systems, connection types and the like.

A basic system architecture of a communication network may comprise a commonly known architecture comprising a wired or wireless access network subsystem and a core network, such as an EPC. Such an architecture comprises one or more access network control units, radio access network

elements, access service network gateways or base

transceiver stations, with which a user equipment is capable to communicate via one or more channels for

transmitting several types of data. Furthermore, core network elements such as gateway network elements, AAA network elements, HSS network elements, policy and charging control network elements and the like are usually

comprised. The general functions and interconnections of these elements are known to those skilled in the art and described in corresponding specifications so that a

detailed description thereof is omitted herein. However, it is to be noted that there may be provided several

additional network elements and signaling links used for a communication connection or a call between user terminals and/or servers than those described in detail herein below. Furthermore, the network elements, such as gateway elements like a PDN GW, an MAG, an ePDG etc., network control elements like a HSS, an AAA server, an MME etc., a UE and the like, and their functions described herein may be implemented by software, e.g. by a computer program product for a computer, or by hardware. In any case, for executing their respective functions, correspondingly used devices and network element comprise several means and components (not shown) which are required for control, processing and communication/signaling functionality. Such means may comprise, for example, a processor unit for executing instructions, programs and for processing data, memory means for storing instructions, programs and data, for serving as a work area of the processor and the like (e.g. ROM, RAM, EEPROM, and the like), input means for inputting data and instructions by software (e.g. floppy diskette, CD-ROM, EEPROM, and the like) , user interface means for providing monitor and manipulation possibilities to a user (e.g. a screen, a keyboard and the like), interface means for establishing links and/or connections under the control of the processor unit (e.g. wired and wireless interface means, an antenna, etc.) and the like.

In Fig. 1, a simplified architecture of an exemplary communication network is shown in which the control of a connection setup via different access networks according to examples of embodiments of the invention may be

implemented. The communication network shown in Fig. 1 is based on a 3GPP EPS wherein access for a subscriber, i.e. the UE 10, is possible via different access networks. It is assumed that the UE 1 is capable of attach to the network via at least two different access networks, for example 3GPP access network 20 and non-3GPP access networks 30, 40 for establishing a connection to a destination, such as IP services 50 provided by the operator.

It is to be noted that the network architecture shown in Fig. 1 depicts only those network elements which are useful for understanding the principles of the examples of embodiments of the invention. As known by those skilled in the art there are several other network elements, such as a policy and charging control element, like a PCRF (policy and charging rule function) involved in the establishment and control of communication connection which are omitted here for the sake of simplicity.

Furthermore, with regard to links or interfaces (also referred to as reference points) between the network elements shown in Fig. 1, the indications provided in Fig. 1 represent only examples for such links. Other definitions or links providing similar functionality may be also used. Referring to Fig. 1, the communication network comprises a plurality of access networks (three are shown in Fig. 1) . A first one is the 3GPP access network 20 comprising a EUTRAN 21, a 2G/3G (GERAN/UTRAN) 22 with an SGSN as being a control element thereof, an MME 23 representing a control node for the 3GPP (LTE) access network, and an SGW 25 for routing and forwarding user data packets. A second one is the (trusted) non-3GPP IP access network 30 linked to an MAG 35 functioning as an access router managing signaling for a UE that is attached to its access link. A third one is the (untrusted) non-3GPP IP access network 40 which connects to an ePDG 45 which functions as an MAG for communication to/from the (untrusted) non-3GPP IP access network 40. It is to be noted that the categorization of the non-3GPP access networks into "trusted" or "untrusted" may be set by the network operator who decides whether the non-3GPP access network can be trusted or not, for example with regard to security issues. The categorization is to be considered with regard to the link path and interfaces to be used for connecting to other network elements (for example whether the ePDG 45 is to be used or not) .

As indicated by arrows in Fig. 1, the UE 10 may attach (also simultaneously) to one or more of the access networks 20, 30 and 40 for establishing, for example, one or more PDN connections to a desired destination. The destination may be identified, for example, by means of an APN. Reference sign 60 denotes a PDN GW. The PDN GW 60 provides connectivity from the UE 10 to external PDNs by being the point of exit and entry of traffic for the UE 10. The PDN GW 60 performs policy enforcement, packet filtering for each user, charging support, lawful Interception and packet screening. Another key role of the PDN GW is to act as the anchor for mobility between 3GPP and non-3GPP technologies such as WiMAX. Reference sign 70 denotes a HSS in which subscriber profile information of the subscriber and information related to the PDN GW and the connections established via it to different APNs, such as a PDN GW identity, are

stored/registered. The HSS 70 is able to provide this information to network elements of the respective access networks requesting an establishment of a connection for the UE 10, such as the MME 23 of the 3GPP access network 20. Regarding the non-3GPP IP access networks 30 and 40, this information may be provided by the HSS 70 via an AAA network element 80 which may maintain information

associated with UE access to the EPC and provide

authorization and other network services.

Regarding the interfaces or reference points providing links between the network elements shown in Fig. 1, S5 provides user plane tunneling and tunnel management between the SGW 25 and PDN GW 60; S6a enables transfer of

subscription and authentication data for

authenticating/authorizing user access to the evolved system (AAA interface) between the MME 23 and the HSS 70;

S2a provides the user plane with related control and mobility support between the trusted non 3GPP IP access network 30 and the gateway; S2b provides the user plane with related control and mobility support between ePDG and the Gateway (i.e. when access via untrusted non-3GPP access network 40 is established) ; S2c provides the user plane with related control and mobility support between the UE 10 and the Gateway (usable over trusted and/or untrusted non- 3GPP access and/or 3GPP access networks) ; S6b is the reference point between PDN GW 60 and the AAA server/proxy 80 for mobility related authentication; SWa connects the untrusted non-3GPP IP access network 40 with the AAA

Server/Proxy 80 and transports access authentication, authorization and charging-related information in a secure manner; STa connects the trusted non-3GPP IP access network 30 with the AAA Server/Proxy 80 and transports access authentication, authorization, mobility parameters and charging-related information in a secure manner; SWm is located between the AAA Server/Proxy 80 and ePDG 45 and is used for AAA signaling; SWn is between the untrusted non- 3GPP IP access network 40 and the ePDG 45; SWx is located between the AAA Server 80 and the HSS 70 and is used for transport of authentication, subscription and PDN

connection related data.

In the following, an example of an embodiment of the invention regarding a mechanism for controlling setup of a connection is described with reference to a flow chart according to Fig. 2. Specifically, Fig. 2 shows a procedure for controlling the setup of a PDN connection to a

specified APN via a PDN gateway element, wherein different access networks are usable by the UE requesting the PDN connection .

When a new PDN connection is established, a request

regarding the establishment of the PDN connection is sent from the UE through the access network to which it is attached towards the EPC. A corresponding request message is then received at the PDN GW 60 at step S100.

In step S110, it is detected by the PDN GW 60 which access network is to be used for the PDN connection (e.g. a 3GPP access network) , for example by means of information comprised in the request message. Furthermore, it is also recognized which destination, i.e. which APN, is concerned.

In step S120, the PDN GW 60 checks if there is another existing PDN connection to the specified APN wherein this other PDN connection is established/using another access network being different to that via which the current setup request has been received (for example a non-3GPP access network) .

If it is determined in step S130, based on the check of step S120, that there is no such PDN connection (i.e. no other PDN connection of the requesting UE to the specified APN via another network exists or is established at the PDN GW 60), the processing proceeds to step S160. In step S160, the setup request is allowed, i.e. a normal setup

processing for the PDN connection to the APN is performed, as requested.

Otherwise, if it is determined in step S130, based on the check of step S120, that there is such PDN connection (i.e. another PDN connection of the requesting UE to the

specified APN via another network exists or is established at the PDN GW 60), the processing proceeds to step S140. In step S140, the setup request is rejected. Then, in step S150, an indication to the requesting side is sent by means of a proper error cause, for example.

It is to be noted that the procedure described in

connection with Fig. 2 may be executed by the PDN GW 60, according to examples of embodiments of the invention.

In Fig. 3, a block circuit diagram of a network element, such as the PDN GW 60, is shown which is configured to implement the control mechanism described in connection with Fig. 2. It is to be noted that the network element 60 shown in Fig. 3 may comprise several further elements or functions besides those described in connection therewith but which are omitted herein for the sake of simplicity as they are not essential for understanding the invention. The network element 60 configured to execute, for example, a control procedure according to Fig. 2 may comprise a processing function or processor 61, such as a CPU or the like, which executes instructions given by programs or the like related to the power control. The processor 61 may comprise further portions dedicated to specific processings described below. Portions for executing such specific processings may be also provided as discrete elements or within one or more further processors, for example.

Reference sign 62 denotes transceiver or input/output (I/O) units connected to the processor 61 (or corresponding other elements comprising the functions of the further portions) . The I/O unit 62 may be used for communicating with the network elements, such as the SGW (MME) , ePDG, MGW, AAA entity shown in Fig. 1 via respective reference points (not shown) . The I/O unit 62 may be a combined unit comprising the communication equipment towards all network elements in question, or may comprise a distributed structure with a plurality of different interfaces. Reference sign 63 denotes a memory usable, for example, for storing data and programs to be executed by the processor 61 and/or as a working storage of the processor 61.

The processor 61 is configured to execute processings related to the control for the connection setup via

different access networks described in examples of

embodiments of the invention. For example, the processor 61 comprises a receiver portion 611 which receives a request regarding the establishment of a PDN connection and

triggers, on the basis of the information contained in the request, the further processing for controlling the

connection setup. Reference sign 612 denotes a detector (detecting portion) which detects the used access network (i.e. the access network via which the request is sent and which is thus the access via which the connection is to be conducted) as well as the destination (the APN) towards which the PDN connection is to be setup. Reference sign 613 denotes processing portion which conducts the check of whether or not there are, via another access network being different to the access network from which the setup request was received, any other PDN connection ( s ) to the APN to which the new PDN connection is directed. Reference sign 614 denotes a processing portion which, depending on the result of the check in portion 613, rejects the setup request (in case there are other PDN connections to the specified APN via another access network) or allow to further proceed with the processing of the setup request for establishing the PDN connection (in case there are no other PDN connections to the specified APN via another access network) .

As described above, in the mechanism for controlling the setup of a connection to a specified destination according to the example of embodiments of the invention described in connection with Figs. 2 and 3, it is checked whether any other PDN connections from the PDN GW to the specified APN via another access network exist. In this connection, it is to be noted that it is required that all PDN connections to the same APN shall use the same PDN GW.

In order to fulfill this requirement that the same PDN GW is selected from different access networks for a connection to a specific APN, according to examples of embodiments of the invention, the following procedures are executed.

In general, according to examples of embodiments of the invention, up-to-date information about the PDN GW in use for a given APN via any access network is provided when a new PDN connection is being set up via any other access. This may take place, for example, when the UE attaches to any other access network, and default PDN connection is setup, or basically at any time after an attach, when the UE requests a setup of new PDN connection. For this

purpose, the PDN GW identity for a specific APN may be stored in the HSS from which corresponding information can be retrieved or provided.

In order to ensure that the same PDN GW is used for a connection to a specified APN via any access network, according to examples of embodiments of the invention, a new PDN GW selection algorithm may be provided which comprises the following measures. When the UE is making an attach to an access network, i.e. even if the UE has no PDN connection via the given access network, PDN GW identity information is received from the HSS in connection with subscription information. This received PDN GW identity information comprised in the subscription profile is then to be selected. In other words, it is not allowed to select a new PDN GW if the UE has no active PDN connection to the given APN.

Furthermore, according to examples of embodiments of the invention, when a new PDN GW identity is stored or

registered in the HSS (or HSS /AAA entity) , the HSS (or HSS /AAA entity) pushes the PDN GW identity of a given subscriber to all access networks where to UE is connected to. This measure can be easily implemented and is thus in particular advantageous as the HSS/AAA is usually able to send the subscription profile which may comprise this information. Moreover, since the new PDN GW identity is already registered in the HSS (or HSS/AAA entity) , further changes in processing or data content of the HSS (or

HSS/AAA entity) is not required.

By means of these measures, it is possible to ensure that any subsequent PDN connection to the specified APN from any other access network uses the same PDN GW as all access networks connecting to a PDN GW are informed which PDN GW is in charge of the respective APN.

In the examples of embodiments of the invention described above in connection with Figs. 2 and 3, the mechanism for controlling the setup of a connection to a specified destination is mainly conducted in the PDN GW element.

According to further examples of embodiments of the

invention, a corresponding processing, i.e. a control of the setup of connections to a specified APN, may be

executed also in other network elements. For example, the check whether any other PDN connections from a selected PDN GW to the specified APN via another access network exist can be conducted in another element.

For example, when a new PDN connection is established to an APN to which presently no PDN connection is established via the access network used by the UE for this PDN connection setup request, the check whether any other PDN connections from a selected PDN GW to the specified APN via another access network exist may be executed by the network element that selects the PDN GW.

Specifically, according to one example of embodiments of the invention, in case the access network is the 3GPP access network 20, the MME 23 checks if there is another PDN connection to the specified APN via another access network. Alternatively, according to one other example of embodiments of the invention, in case the access network is a non-3GPP access network and an interface corresponding to the S2a reference point shown in Fig. 1 is used (i.e. when the access network is the non-3GPP IP access network 30), the MAG 35 checks if there is another PDN connection to the given APN via another access network. As a further

alternative, according to one other example of embodiments of the invention, in case the access network is a non-3GPP access network and an interface corresponding to the S2b reference point shown in Fig. 1 is used (i.e. when the access network is the non-3GPP IP access network 40), the ePDG 45 checks if there is another PDN connection to the given APN via another access network. (In this connection, it is to be noted that in case an interface corresponding to the S2c reference point is used, where the UE performs the PDN GW selection, the PDN GW itself check if there is another PDN connection to the given APN via another access network when an interface corresponding to S2c is used.)

In the above described examples, where the check whether any other PDN connections from a selected PDN GW to the specified APN via another access network exist is executed by the network element that selects the PDN GW, it has to be ensured that the respective network element that

performs the PDN GW selection (i.e. the MME, the MAG or the ePDG, for example) has up-to-date information about the active PDN connections via other access networks at the selected PDN GW. For this purpose, according to these examples of embodiments of the invention, whenever a PDN connection is established or released, a corresponding information is sent to the HSS (or HSS/AAA entity) which in turn sends this information to the other access networks where the UE is connected to, according to the subscription profile information, for example. Thus, the HSS (or HSS/AAA entity) interacts with the network elements associated to the access networks and being responsible for the PDN GW selection (and the control of the setup of connections according to the respective examples of embodiments of the invention) , wherein the respective network elements have to be configured to send information related to the

establishment/release of a PDN connection and to receive and process corresponding information from the HSS

accordingly .

According to a further example of embodiments of the invention, in contrast to the above described example of embodiments of the invention where the mechanism for controlling the setup of a connection to a specified destination is mainly conducted in the PDN GW element, a corresponding processing, i.e. a control of the setup of connections to a specified APN comprising the check whether any other PDN connections from a selected PDN GW to the specified APN via another access network exist, may be conducted in a network element used for subscription or authentication/authorization control .

For example, when a new PDN connection is established to an APN to which presently no PDN connection is established via the access network used by the UE for this PDN connection setup request, the check whether any other PDN connections from a selected PDN GW to the specified APN via another access network exist may be executed by the AAA/HSS entity. Similar to the above described examples of embodiments of the invention, for this purpose, whenever a PDN connection is established or released, a corresponding information is sent to the HSS (or HSS/AAA entity) . Thus, the HSS (or HSS/AAA entity) interacts with the network elements

associated to the access networks, wherein the respective network elements have to be configured to send information related to the establishment/release of a PDN connection to the HSS accordingly.

In the following, an example of an embodiment of the invention regarding a mechanism for controlling setup of a connection is described with reference to a flow chart according to Fig. 4. Specifically, Fig. 4 shows a procedure where the control of the setup of a PDN connection to a specified APN via a PDN gateway element, wherein different access networks are usable by the UE requesting the PDN connection, is conducted in the network element selecting the PDN GW, as described above. When a new PDN connection is established, a request

regarding the establishment of the PDN connection is sent from the UE to a control element of the access network to which it is attached. A corresponding request message is then received at the control network element, for example the MME 23 or the MAG 35, at step S200.

In step S210, the control network element, for example the MME 23, selects the PDN GW, for example on the basis of information received from the HSS 70 (or from the AAA entity 80 in case of a non-3GPP access network) , and receives further information regarding connections already existing to the specified APN at the selected PDN GW, together with information regarding the involved access network.

Step S220 concerns an example where the control is effected by the HSS/AAA entity which is described below. For the processing in case the network element selecting the PDN GW is involved, step S220 is not necessary. Therefore, in this example, step S230 follows where the network element (e.g. the MME 35) checks if there is another existing PDN

connection to the specified APN wherein this other PDN connection is established/using another access network being different to that associated to the network element

(like the 3GPP access network 20) .

If it is determined in step S240, based on the check of step S230, that there is no such PDN connection (i.e. no other PDN connection of the requesting UE to the specified

APN via another network exists or is established at the PDN GW 60), the processing proceeds to step S270. In step S270, the setup request is allowed, i.e. a normal setup

processing for the PDN connection to the APN is performed, as requested. Otherwise, if it is determined in step S240, based on the check of step S230, that there is such PDN connection (i.e. another PDN connection of the requesting UE to the

specified APN via another network exists or is established at the PDN GW 60), the processing proceeds to step S250. In step S250, the setup request is rejected. Then, in step S260, an indication to the requesting side is sent by means of a proper error cause, for example. The processing in Fig. 4 is different to some extent in case the control is effected by the HSS/AAA entity. Then, in step S200, when a new PDN connection is established and a request regarding the establishment of the PDN connection is sent from the UE to a control element of the access network to which it is attached, a corresponding request information is received at the HSS/AAA entity from the control network element, for example the MME 23 or the MAG 35, at step S200. In this case, in step S210, the HSS/AAA entity selects the

PDN GW, for example on the basis of information stored in the HSS 70, and considers further information regarding connections already existing to the specified APN at the selected PDN GW, together with information regarding the involved access network.

In step S220, it is also determined, with regard to the present setup request, which access network is to be used for the new PDN connection (e.g. a 3GPP access network), Furthermore, it is also recognized which destination, i.e which APN, is concerned.

The further processing regarding steps S230 to S270

corresponds basically to the above described processing and is thus not repeated. Thus, according to examples of embodiments of the

invention, the procedures described in connection with Fig. 4 may be executed by control network elements, like the MME, the ePDG or the MAG, or by subscription and

authentication network elements, like an HSS/AAA entity.

In Fig. 5, a block circuit diagram of a network element 100, such as a control network element like the MME, the ePDG or the MAG, or a subscription and authentication network element, like an HSS/AAA entity, is shown which is configured to implement the control mechanism described in connection with Fig. 4. It is to be noted that the network element 100 shown in Fig. 3 may comprise several further elements or functions besides those described in connection therewith but which are omitted herein for the sake of simplicity as they are not essential for understanding the invention .

The network element 100 configured to execute, for example, a control procedure according to Fig. 4 may comprise a processing function or processor 101, such as a CPU or the like, which executes instructions given by programs or the like related to the power control. The processor 101 may comprise further portions dedicated to specific processings described below. Portions for executing such specific processings may be also provided as discrete elements or within one or more further processors, for example.

Reference sign 102 denotes transceiver or input/output (I/O) units connected to the processor 101 (or

corresponding other elements comprising the functions of the further portions) . The I/O unit 102 may be used for communicating with the network elements, such as the SG (MME), ePDG, MGW, AAA entity shown in Fig. 1 via respective reference points (not shown) , in dependence which network element the network element 100 represents. The I/O unit

102 may be a combined unit comprising the communication equipment towards all network elements in question, or may comprise a distributed structure with a plurality of different interfaces. Reference sign 103 denotes a memory usable, for example, for storing data and programs to be executed by the processor 101 and/or as a working storage of the processor 101.

The processor 101 is configured to execute processings related to the control for the connection setup via

different access networks described in examples of

embodiments of the invention. For example, the processor

101 may comprise a receiver portion (not shown) which receives a request regarding the establishment of a PDN connection and triggers, on the basis of the information contained in the request, the further processing for controlling the connection setup. Furthermore, a receiver portion 1011 may be provided which is configured to receive information regarding the presently established PDN

connections at the PDN GW, together with information about the access networks used therefor. Reference sign 1012 denotes a detector (detecting portion) which detects the used access network (i.e. the access network via which the request is sent and which is thus the access via which the connection is to be conducted) as well as the destination (the APN) towards which the PDN connection is to be setup. This portion 1012 is in particular involved when the network element is part of the HSS/AAA entity

(corresponding to step S220 in Fig. 4). Reference sign 1013 denotes processing portion which conducts the check of whether or not there are, via another access network being different to the access network via which the setup request for the new PDN connection was started, any other PDN connection ( s ) to the APN to which the new PDN connection is directed. Reference sign 1014 denotes a processing portion which, depending on the result of the check in portion 1013, rejects the setup request (in case there are other

PDN connections to the specified APN via another access network) or allow to further proceed with the processing of the setup request for establishing the PDN connection (in case there are no other PDN connections to the specified APN via another access network) . For the purpose of the present invention as described herein above, it should be noted that

- an access technology via which signaling is transferred to and from a network element or node may be any technology by means of which a node can access an access network (e.g. via a base station or generally an access node) . Any present or future technology, such as WLAN (Wireless Local Access Network) , WiMAX (Worldwide Interoperability for Microwave Access) , BlueTooth, Infrared, and the like may be used; although the above technologies are mostly wireless access technologies, e.g. in different radio spectra, access technology in the sense of the present invention implies also wirebound technologies, e.g. IP based access technologies like cable networks or fixed lines but also circuit switched access technologies; access technologies may be distinguishable in at least two categories or access domains such as packet switched and circuit switched, but the existence of more than two access domains does not impede the invention being applied thereto,

- usable access networks may be any device, apparatus, unit or means by which a station, entity or other user equipment may connect to and/or utilize services offered by the access network; such services include, among others, data and/or (audio-) visual communication, data download etc . ;

- a user equipment may be any device, apparatus, unit or means by which a system user or subscriber may experience services from an access network, such as a mobile phone, personal digital assistant PDA, or computer;

- method steps likely to be implemented as software code portions and being run using a processor at a network element or terminal (as examples of devices, apparatuses and/or modules thereof, or as examples of entities including apparatuses and/or modules therefor), are

software code independent and can be specified using any known or future developed programming language as long as the functionality defined by the method steps is preserved; - generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the invention in terms of the functionality implemented;

- method steps and/or devices, apparatuses, units or means likely to be implemented as hardware components at a terminal or network element, or any module (s) thereof, are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor) , CMOS

(Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-

Transistor Logic), etc., using for example ASIC

(Application Specific IC (Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device) components or DSP

(Digital Signal Processor) components; in addition, any method steps and/or devices, units or means likely to be implemented as software components may for example be based on any security architecture capable e.g. of

authentication, authorization, keying and/or traffic protection;

- devices, apparatuses, units or means can be implemented as individual devices, apparatuses, units or means, but this does not exclude that they are implemented in a distributed fashion throughout the system, as long as the functionality of the device, apparatus, unit or means is preserved,

- an apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of an apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code

portions for execution/being run on a processor;

- a device may be regarded as an apparatus or as an

assembly of more than one apparatus, whether functionally in cooperation with each other or functionally

independently of each other but in a same device housing, for example.

As described above, there is proposed a mechanism for controlling setup of a packet data network connection to a specified access point name via a gateway network element wherein different access networks are usable. When a request regarding a setup of a new packet data network connection to a specified access point name via the gateway network element is received, it is checked, based on the access network used for setting up the connection whether or not there is another connection to the specified access point name via the gateway network element via another different access network. If there is such a connection, the setup request is rejected. Otherwise, the setup of the connection via the gateway network element is allowed.

According to further examples of embodiments, there is provided an apparatus comprising a receiver configured to receive, when a user equipment is attached to an access network, subscription profile information comprising identity information of a gateway, and a selector

configured to select a gateway for an establishment of a new connection to a specified destination in accordance with the received identity information of a gateway.

Furthermore, according to further examples of embodiments, there is provided an apparatus comprising means configured to receive and store information comprising a gateway identity indicating a gateway used for a connection of a subscriber to a specific destination or access point name, and means configured to push information comprising the gateway identity to every access network to which the subscriber is attached.

Specifically, the same gateway network element, like a PDN GW, is selected for a connection to a specific destination (APN) for all access networks.

According to further examples of embodiments of the

invention, there is provided an apparatus comprising receiving means for receiving a request regarding a setup of a new connection to a specified destination via a gateway network element, detecting means for detecting which access network is used for setting up the connection, wherein the detected access network is regarded as a first access network, and processing means for determining whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network, wherein the processing means are also provided for rejecting, when the determination is positive, the setup request, or for allowing, when the determination is negative, the setup of the connection via the gateway network element.

According to further examples of embodiments of the

invention, there is provided an apparatus comprising receiving means for receiving, when a user equipment is attached to an access network, subscription profile

information comprising identity information of at least one gateway network element, and selecting means for selecting a specific gateway network element for an establishment of a new connection to a specified destination in accordance with the received identity information of the at least one gateway network element, wherein the selecting means is configured to always select the same gateway network element for establishing a connection to the specified destination irrespective of which access network is used. According to further examples of embodiments of the

invention, there is provided an apparatus comprising means for receiving and means for storing information comprising a gateway network element identity indicating a gateway network element used for a connection of a subscriber to a specified destination, and means for pushing information comprising the gateway identity to every access network to which the subscriber is attached, wherein the information is usable to always select the same gateway network element for establishing a connection to a specified destination irrespective of which access network is used.

Although the present invention has been described herein before with reference to particular embodiments thereof, the present invention is not limited thereto and various modifications can be made thereto.

Claims

1. Method comprising:

receiving a request regarding a setup of a new

connection to a specified destination via a gateway network element,

detecting which access network is used for setting up the connection, wherein the detected access network is regarded as a first access network, and

determining whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network,

the method further comprising

rejecting, when the determining is positive, the setup request, or

allowing, when the determining is negative, the setup of the connection via the gateway network element.

2. The method according to claim 1, further comprising

sending, when the setup request is rejected, a

corresponding error cause indication towards the requesting side.

3. The method according to claim 1 or 2 , wherein the connection is a packet data network connection.

4. The method according to any of claims 1 to 3, wherein the destination is indicated by a specific access point name .

5. The method according to any of claims 1 to 4, wherein the first access network comprises one of an access network based on 3GPP or an access network not based on 3GPP, and the second access network comprises the other one of the access network based on 3GPP or the access network not based on 3GPP .

6. The method according to any of claims 1 to 5, wherein the method is executed by the gateway network element.

7. The method according to claim 6, wherein the gateway network element is set to be selected for establishing a connection to the specified destination irrespective of which access network is used.

8. The method according to any of claims 1 to 5, wherein the method is executed by a network element allocated to the first access network and connected to the gateway network element, wherein the method further comprises

receiving information regarding an establishment or a release of connections established via the gateway network element to the destination, wherein the information

indicates also which access network is used, wherein the determination of whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network, is based on the received information.

9. The method according to any of claims 1 to 5, wherein the method is executed by a home subscriber server system, wherein the method further comprises

10. The method according to any of claims 8 and 9, further comprising

selecting always the same gateway network element for establishing a connection to the specified destination irrespective of which access network is used as the first access network.

11. Apparatus comprising:

a receiver configured to receive a request regarding a setup of a new connection to a specified destination via a gateway network element,

a detector configured to detect which access network is used for setting up the connection, wherein the detected access network is regarded as a first access network, and a processor configured to determine whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network,

wherein the processor is further configured

to reject, when the determination is positive, the setup request, or

to allow, when the determination is negative, the setup of the connection via the gateway network element.

12. The apparatus according to claim 11, wherein the processor is further configured to

send, when the setup request is rejected, a

corresponding error cause indication towards the requesting side .

13. The apparatus according to claim 11 or 12, wherein the connection is a packet data network connection.

14. The apparatus according to any of claims 11 to 13, wherein the destination is indicated by a specific access point name.

15. The apparatus according to any of claims 11 to 14, wherein the first access network comprises one of an access network based on 3GPP or an access network not based on 3GPP, and the second access network comprises the other one of the access network based on 3GPP or the access network not based on 3GPP.

16. The apparatus according to any of claims 11 to 15, wherein the apparatus is comprised in the gateway network element .

17. The apparatus according to claim 16, wherein the gateway network element is set to be selected for

establishing a connection to the specified destination irrespective of which access network is used.

18. The apparatus according to any of claims 11 to 15, wherein the apparatus is comprised in a network element allocated to the first access network and connected to the gateway network element, wherein the apparatus further comprises

a receiver configured to receive information regarding an establishment or a release of connections established via the gateway network element to the destination, wherein the information indicates also which access network is used, wherein the processor is configured to determine whether or not there is another connection to the specified destination via the gateway network element, which other connection is established via a second access network being different from the first access network, on the basis of the received information.

19. The apparatus according to any of claims 11 to 15, wherein the apparatus is comprised in a home subscriber server system, wherein the apparatus further comprises

20. The apparatus according to any of claims 18 and 19, further comprising

a selector configured to always select the same gateway network element for establishing a connection to the specified destination irrespective of which access network is used as the first access network.

21. Method comprising

receiving, when a user equipment is attached to an access network, subscription profile information comprising identity information of at least one gateway network element, and

selecting a specific gateway network element for an

establishment of a new connection to a specified

destination in accordance with the received identity information of the at least one gateway network element, wherein always the same gateway network element is selected for establishing a connection to the specified destination irrespective of which access network is used.

22. Apparatus comprising

a receiver configured to receive, when a user equipment is attached to an access network, subscription profile information comprising identity information of at least one gateway network element, and

a selector configured to select a specific gateway network element for an establishment of a new connection to a specified destination in accordance with the received identity information of the at least one gateway network element, wherein the selector is configured to always select the same gateway network element for establishing a connection to the specified destination irrespective of which access network is used.

23. Method comprising

receiving and storing information comprising a gateway network element identity indicating a gateway network element used for a connection of a subscriber to a

specified destination, and

pushing information comprising the gateway identity to every access network to which the subscriber is attached, wherein the information is usable to always select the same gateway network element for establishing a connection to a specified destination irrespective of which access network is used.

24. Apparatus comprising

means configured to receive and store information

comprising a gateway network element identity indicating a gateway network element used for a connection of a

subscriber to a specified destination, and

means configured to push information comprising the gateway identity to every access network to which the subscriber is attached, wherein the information is usable to always select the same gateway network element for establishing a connection to a specified destination irrespective of which access network is used.

25. A computer program product for a computer, comprising software code portions for performing the steps of any of claims 1 to 10, 21 and 23, when said product is run on the computer .

26. A computer program product according to claim 25, wherein said computer program product comprises a computer- readable medium on which said software code portions are stored .

27. A computer program product according to claim 25, wherein said computer program product is directly loadable into the internal memory of the computer.