WO2004077757A1

WO2004077757A1 - Method for negotiating data connections in a wlan network

Info

Publication number: WO2004077757A1
Application number: PCT/DE2003/004195
Authority: WO
Inventors: Jochen Grimminger
Original assignee: Siemens Aktiengesellschaft
Priority date: 2003-02-28
Filing date: 2003-12-18
Publication date: 2004-09-10

Abstract

The invention relates to a method for transmitting data in a WLAN network (1) (Wireless Local Area Network), whereby WLAN messages are transmitted in the Layer 2 protocol layer between a terminal (UE) and an access node (AP) of the WLAN network (1). The WLAN messages contain specific messages about possible data connections, via the access node (AP), between the terminal (UE) and the data networks (2, 3) that can be connected to the WLAN network (1).

Description

description

_Traversing EN _Z UR NEGOTIATION OF DATA CONNECTIONS IN A WLAN NETWORK

The invention relates to a method for transmitting data in a WLAN network and a corresponding device for transmitting such data and a corresponding data network.

For some years now, the transmission of data via wireless WLAN networks has become more widespread. WLAN stands for "Wireless Local Area Network" and refers to a local wireless network with ranges of a few hundred meters. In the meantime, users of end devices, in particular mobile radio devices and laptops, have the option of logging into commercially operated WLÄN networks at any location. The user can locate a large number of WLAN networks via his terminal, each WLAN network comprising so-called access nodes (usually referred to as access points), via which the user can access further data networks, in particular the Internet or UMTS networks , can provide.

There are currently no adequate mechanisms which enable the user to select suitable WLAN networks for data transmission based on predetermined criteria for user-specific applications. Nowadays, the user essentially tries out a connection of his terminal device to a WLAN network, hoping that this connection is suitable for his needs. This means that if a user wants to determine whether a data connection has a desired property, he first has to log in lengthily via the access node of the WLAN network.

The object of the invention is therefore to provide a method for transmitting data in a WLΔN network, in which the user can check which data connection via the Access node of the WLAN network is suitable for its needs.

This task is solved by the independent claims. Further developments of the invention result from the dependent claims.

In the method according to the invention, WLAN messages are transmitted in the L2 protocol layer (L2 = Layer 2) between a terminal and an access node of the WLAN network. The WLAN messages contain specific messages about possible data connections of the terminal via the access node to data networks that can be connected to the WLAN network. This makes it possible to direct inquiries or information regarding possible data connections to the access node or to data networks that can be connected to the access node. Before the data connection is initialized, it can thus be clarified whether a data connection desired by the user is possible or which data connections can be established at all via the WLAN network.

In a particularly preferred embodiment, the specific messages are evaluated and, depending on the evaluation, a decision is made as to whether or which data connection of the terminal via the access node to one or more of the data networks which can be connected to the WLAN network is used for data transmission. The user of the terminal can thus automatically be provided with the data connection he or she wishes, or the user can be informed that the data connection required for his purposes is not possible at all via the WLAN network.

The specific messages preferably contain requests and / or information relating to the authentication of the terminal at the access node and / or in one or more of the data networks that can be connected to the WLAN network. Furthermore, the specific messages preferably contain requests and / or information relating to one or more data connection types and / or data connection qualities and / or data connection east and / or services provided by the data connection. The user of the terminal is thus given a variety of decision criteria according to which he can specify his desired data connection.

In a particularly preferred embodiment, the specific messages are tunneled in the WLAN messages.

In a further particularly preferred embodiment, the specific messages are transmitted in the form of SIP messages (SIP = Session Initiation Protocol), the SIP messages containing SDP messages (SDP = Session Description Protocol) in which at least some of the specific messages are saved. The SIP / SDP protocols just mentioned are well known from the prior art; reference is made here, for example, to references [1] and [2]. The terms SIP and SDP include the currently used SIP or SDP protocols as well as SIP or SDP protocols currently under development, such as SIPng (= SIP next generation) or SDPng (= SDP) next generation). Both protocols are used in IP-based networks to initialize or describe a protocol session. The use of SIP / SDP messages ensures transmission of the specific messages in other networks, for example in IP-based networks, which are usually connected to WLAN access nodes. Such SIP / SDP messages are preferably evaluated in one or more SIP proxy CSCF servers (CSCF = Call State Control Function). The SIP / SDP messages can be, for example, probe request and / or probe response messages of the WLÄN protocol. Alternatively, however, the messages can also be newly defined messages in the WLAN protocol. In a further preferred embodiment of the invention, the SIP messages contain SIP authentication data and the SIP messages are contained in EAP messages (EAP = Extensible Authentication Protocol). The EAP protocol is well known from the prior art (see for example [4]). This protocol is used to provide authentication mechanisms for a point-to-point connection, the mechanisms Digest, Kerberos, USIM and the like known from the prior art being used in particular as authentication mechanisms. This ensures authentication in all data networks that understand the SIP protocol.

In a further embodiment, the SIP authentication data are extracted and used as authentication data in the RADIUS and / or diameter protocol (RADIUS = Remote Authentication Dial In User Service). These protocols are well known from the prior art (see [4] and [5]). This provides a mechanism with which SIP authentication can be used in the frequently used RADIUS or diameter protocols.

Instead of the use of SIP / SDP messages described above, the use of XML messages is also conceivable. XML is a well-known description language for documents (see [6]).

In a particularly preferred embodiment, the WLAN messages are messages in accordance with the WLAN standard IEEE 802.11. Furthermore, the networks that can be connected to the WLAN network preferably comprise one or more 3GPP and / or IP networks.

In addition to the transmission method according to the invention described above, the invention also includes a device for Transmission of data in a WLAN network, the device comprising:

an access node, wherein WLAN messages can be transmitted in the L2 protocol layer between the access node and a terminal, and specific messages about possible data connections of the terminal can be transmitted in the WLAN messages via the access node to networks that can be connected to the WLAN network,

- A computing unit connected to the access node for evaluating the specific messages.

In a particularly preferred embodiment of the device according to the invention, the computing unit is an SIP proxy CSCF server. Furthermore, the computing unit is preferably integrated in the access node.

In addition, the invention comprises a data network with a WLAN network and one or more networks which can be connected to the WLAN network, the data network being designed such that the method according to the invention described above can be carried out.

Embodiments of the invention are described below with reference to the accompanying drawings.

Show it:

Figure 1 is a schematic representation of a data network in which the data transmission method according to the invention can be carried out, and

Figure 2 shows an overview of the messages used in the WLAN protocol. That in ^; "Figure -il schematically shown data network." Includes a WLAN network 1, an IP network 2 and a 3GPP network 3. A user terminal UE, which can be, for example, a mobile radio device or a laptop, is wireless (as by the jagged arrow indicated), connected to an access point AP (AP = Access Point) of the WLAN network, which in turn is connected to a proxy CSCF server P-CSCF. Such servers are already state of the art known and they are used to process so-called SIP / SDP messages.

An IP network 2 is connected to the access node AP or to the P-CSCF server P-CSCF. This network is in turn connected to a 3GPP network 3. The 3GPP network comprises a large number of components with the designations SGSN, GGSN, HSS,

IMS, P-CSCF, I-CSCF, S-CSCF and PDGW. The components designated with these abbreviations are well-known building blocks of a 3GPP network and the terms hidden behind the abbreviations are generally known to the person skilled in the art. Since the structure of the 3GPP network does not play a decisive role for the method according to the invention, this structure will not be discussed in more detail below. It should only be mentioned that the IP network is connected to the 3GPP network via the gateway PDGW.

In the method according to the invention, WLAN messages in the L2 protocol layer are exchanged between the user terminal UE and the access node AP, SIP messages containing SDP messages being tunneled in the WLAN messages. These SIP messages are generated without the assignment of an IP address and can be processed by the P-CSCF server, which is connected to the access node AP. The method according to the invention is characterized in that in the embodiment described here, inquiries or information about possible data connections of the terminal UE are transmitted in the SDP messages via the access node AP to the IP network 2 and / or the 3GPP network 3. These inquiries or information can in particular include an access request which is determined by the user of the terminal. For example, the access request can relate to the type of data connection with which data transmission via the access node is to take place. For example, the user can specify that the data connection should take place over the Internet. Furthermore, such a request can relate to a bandwidth desired by the user or a delay or jitter of the data connection. It is therefore possible to select the provider, for example in foreign foreign networks, according to predetermined criteria.

The arrows P1, P2 and P3 in FIG. 1 show, for example, the path of a request sent by the terminal UE. The request is transmitted in the form of a SIP message and first reaches the access node AP and the P-CSCF server P-CSCF connected to the access node via the path P1. This server can interpret and evaluate SIP messages. Already in the P-CSCF-

Server that a desired bandwidth is not available at all in networks 2 and 3, a response is immediately sent back to the terminal UE, with which the terminal is informed that the desired data connection is not possible. This response is transmitted to the terminal via path P5 shown in FIG. 1.

If it turns out during the evaluation of the SIP messages that a data connection desired by the user can possibly be established through one of the data networks, the SIP messages are forwarded to further P-CSCF or S-CSCF servers, as indicated by arrows P2 or P3 is indicated. The content of the SIP messages makes it clear which server is responsible for the terminal UE - for example for authentication - and this server is addressed via the SIP messages. This creates a so-called SIP message chain. If one of the Server in the chain shows that the desired data connection is possible, a response is sent back to the terminal UE, for example via the paths P4 and P5 shown in FIG. 1. The data connection can then be initialized. The great advantage here is that it can be clarified before the data connection is initialized whether the data connection even meets the requirements desired by the user. Furthermore, it can be determined which data connections are available at all, and the user can select an adequate data connection from the available data connections.

Messages are transmitted between the user interface UE and the access node AP using the authentication protocol EAP (EAP = Extensible Authentication Protocol). In the present case, EAP messages are transmitted, which in turn comprise the SIP messages and SIP authentication data contained in the SIP messages. Mechanisms known to the person skilled in the art, for example Kerberos or Digest, are used as SIP authentication mechanisms. Since the EAP protocol also serves as a carrier for the transmission of encryption information, an effective combination of authentication, key assignment and encryption is achieved with the transmission of specific messages for possible data connections.

In the event that the EAP / SIP messages cannot be processed by a network that can be connected to the WLAN network, there is also the possibility that the SIP authentication data contained in the EAP messages are extracted, for example using the RADIUS protocol in the form of so-called radius key value pairs. Since the RADIUS protocol is a widely used protocol, the compatibility of the authentication in the various data networks is ensured. It should be noted here that it is possible to use SIP authentication data in the RADIUS protocol, since both protocols have the same Use authentication mechanisms. In extreme cases, the SIP authentication data from the SIP messages can even ^so-1 on the extraction be dispensed with and the SIP messages can be transferred in total to the RADIUS protocol.

FIG. 2 shows a table in which the data types used in the WLAN protocol are listed. These data types are well known to the person skilled in the art. For the transmission of the specific messages ^{according to the invention, firstly} known messages, in particular the “probe request ^X ” or “probe response” mentioned in FIG. However, new data types can also be created. Corresponding data types with the designation "Reserved" are provided for this.

list of terms:

org / rfc / rfc3261.txt org / rfc / rfc2327. txt org / rfc / rfc2284.txt org / rfc / rfc2865.txt org / internet-drafts / draft-ietf-aaa-

Claims

claims

1. Method for transmitting data in a WLAN network (1) (WLAN = Wireless Local Area Network), in which

WLAN messages in the L2 protocol layer (L2 = Layer 2) are transmitted between a terminal (UE) and an access node (AP) of the WLAN network (1);

the WLAN messages contain specific messages about possible data connections of the terminal (UE) via the access node (AP) to data networks (2, 3) that can be connected to the WLAN network (1).

2. The method according to claim 1, in which the specific messages are evaluated and, depending on the evaluation, a decision is made as to whether and / or which data connection of the terminal device (UE) via the access node (AP) to one or more of the ones with the WLAN Network (1) connectable data networks (2, 3) is used for data transmission.

3. The method as claimed in claim 1 or 2, in which the specific messages contain inquiries and / or information relating to the authentication of the terminal at the access node and / or in one or more of the data networks which can be connected to the WLAN network.

4. The method as claimed in one of the preceding claims, in which the specific messages contain inquiries and / or information relating to one or more types of data connection and / or data connection qualities and / or data connection costs and / or services provided by the data connection.

5. The method according to one of the preceding claims, in which the specific messages are tunneled in the WLAN messages.

6. The method according to any one of the preceding claims, in which the specific messages are transmitted in the form of SIP messages (SIP = Session Initiation Protocol), the SIP messages containing SDP messages (~~ ^ SDP = Session Description Protocol), in which at least some of the specific messages are stored.

7. The method of claim 2 and claim 6, wherein the evaluation of the specific messages in one or more SIP proxy CSCF servers (CSCF = Call State Control Function) takes place.

8. The method of claim 6 or 7, wherein the messages are probe request and / or probe response messages of the WLAN protocol.

9. The method according to claim 6 or 7, wherein the messages are newly defined in the WLAN protocol messages.

10. The method according to any one of claims 6 to 9, in which the SIP messages contain SIP authentication data and are contained in EAP messages (EAP = Extensible Authentication Protocol).

11. The method according to any one of claims 6 to 10, in which the SIP authentication data is extracted and used as authentication data in the RADIUS and / or diameter protocol (RADIUS = Remote Authentication Dial In User Service).

12. The method according to any one of claims 1 to 5, in which the specific messages are transmitted in the form of XML messages.

13. The method according to any one of the preceding claims, wherein the WLAN messages are messages according to the WLAN standard IEEE 802.11.

14. The method according to any one of the preceding claims, wherein the data networks connectable to the WLAN network (1) comprise one or more 3GPP and / or IP networks.

15. Device for transmitting data in a WLAN network (1) (WLAN = Wireless Local Area Network), comprising

an access node (AP), wherein WLAN messages in the L2 protocol layer (L2 = Layer 2) can be transmitted between the access node (AP) and a terminal (UE) and specific messages about possible data connections of the terminal in the WLAN messages (UE) can be transmitted via the access node (AP) to data networks (2, 3) that can be connected to the WLAN network (1);

a computing unit (S-CSCF) connected to the access node (AP) for evaluating the specific messages.

16. The apparatus of claim 15, wherein the computing unit (S-CSCF) comprises a SIP proxy CSCF server (CSCF = Call State Control Function).

17. The apparatus of claim 15 or 16, wherein the computing unit (S-CSCF) is integrated in the access node (AP).

18. Data network comprising a WLAN network (1) and one or more data networks (2, 3) that can be connected to the WLAN network (1), the data network being configured such that a Method according to one of claims 1 to 14 can be carried out.