3gpp Compliancy v02

7/27/2019 3gpp Compliancy v02

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Document1 CONFIDENTIAL

The uAxes solution 3GPP compliancy

Technical Note

Version: 0.1

Filename: 3gpp_compliancy_v01

Archive: /common/home/.

Editor: Mikko Hurskainen

Version history

Vers. Date/Initials Comment

0.1 20120328/MHu,RSu Initial version0.2 20120329/MHu,RSu Reviewed


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Executive Summary

This document presents the 3GPP standardized I-WLAN solution and the uAxes solution. Theres also acomparison to I-WLAN solution, that which parts are the same and which are different and what is the

reasoning for deviations.

The uAxes solution uses same interfaces towards the core network as the I-WLAN solution. It can be used

also in more standalone fashion, if deep integration with 3G core network is not desired. It provides same

security level as I-WLAN solution.


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Abbreviations

3GPP 3rd

Generation Partnership Project

AAA Authentication, Authorization and Accounting

ANDSF Access Network Discovery and Selection Function

I-WLAN Interworking-WLAN

PCRF Policy and Charging Rules Function

PCEF Policy and Charging Enforcement Function

PDG Packet Data Gateway

WLAN Wireless Local Area Network

UE User equipment


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Table of Contents

Executive Summary ......................................................................................................................................... 2

Abbreviations .................................................................................................................................................. 3

1 Introduction .......................................................................................................................................... 5

2 3GPP I-WLAN solution ........................................................................................................................... 6

3 The uAxes solution ................................................................................................................................ 7

4 Comparison of features and integration ............................................................................................... 8

References ...................................................................................................................................................... 9


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1 IntroductionThis document describes the 3GPP compliancy of the uAxes solution. First the 3GPP reference design for

I-WLAN solution is presented. After that the uAxes solution is presented with differences compared to the

I-WLAN solution. Finally, theres a summary of differences and benefits of each solution.


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2 3GPP I-WLAN solutionThe 3GPP I-WLAN solution is presented in 3GPP TS 29.234. The basic principle of I-WLAN solution is that

the data plane is connected to the core network. The solution adds new elements to existing 3G core

network and reuses some of the elements. The main integration points are the PDG (Packet Data

Gateway) and the WiFi-AAA server.

Figure 1: 3GPP I-WLAN architecture

The WiFi-authentication is EAP-SIM or EAP-AKA that is achieved with HLR/HSS integration. First phase of

the authentication is done when UE accesses the WiFi access network with EAP-SIM/EAP-AKA. The WiFi

network is assumed as untrusted however, and thus there is always a VPN tunnel between the UE and

the network. The establishment of VPN tunnel includes another EAP-SIM/EAP-AKA authentication. VPN is

terminated to PDG that is connected through PCEF to the Internet. The I-WLAN does not require mobile

IP, but it can be run on top of it (as a separate entity). For charging the PCEF and PDG are connected to

OCS and OFCS.

The I-WLAN solution clients can be assisted with ANDSF (3GPP TS 24.312) in network selection. The

ANDSF however, requires a client on platform. Vendors who have implemented the ANDSF have found

the specification missing critical features and thus implemented proprietary extensions.


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3 The uAxes solutionThe uAxes solution is more loosely integrated to the Core Network. It can work also as a standalone

solution. Typically it is integrated to SMSC (SMS Center) and OCS (Online Charging System). SMS is used

for secure messaging and OCS is used for online charging & subscriber validation. HLR/HSS integration is

normally not required because OCS is integrated to HLR/HSS.

Figure 2: uAxes solution

For charging and policy the uAxes can either be integrated to OCS for billing and charging or there can bea PCRF & a PCEF. In PCEF case it is responsible billing, charging and traffic monitoring. In alternative 1

(without PCEF), traffic monitoring is handled on the Wifi network side. The accounting in alternative 1 is

based on RADIUS accounting. The alternative 1 is more cost-efficient and scalable solution and thus

recommended. The alternative 2 is same as 3GPP I-WLAN solution. In alternative 2, the PCEF can be

centralized (as in I-WLAN), but it can also be be distributed to Access Points, Wireless Access Controllers

and internet gateways.

In the uAxes the user is authenticated with SMS and in the WiFi, who is then granted temporary

credentials. The SMS authentication is based on already existing authentication between SIM card and

the network. Temporary credentials can be on any WiFi authentication scheme (WISPr, EAP, PEAP, PSK).The temporary credentials are only given after user is authenticated, whereas in I-WLAN the user is first

let into the access network and then authenticated. The solution is as secure as EAP-SIM.

The access network is assumed to be secure and thus theres no need for end-to-end VPN tunnel.

However, the access point and the AC (Access Controller) can be connected with VPN tunnel if access

network is not secure. The uAxes solution does not require VPN between UE and network and thus does

not interfere with other VPNs solutions, such as Enterprise-VPNs. Also the handover between 3G and

WiFi is faster when VPN tunnel establishment is not required.


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4 Comparison of features and integrationThe table below lists the features of two solutions and the integration required to core network.

Feature: 3GPP uAxes

User authentication EAP-SIM + VPN SMS / SIM based

Core network integration Always Optional

Billing & Charging Gy, Gz interfaces Gy, Gz or WS/SOAP

Client required No, if without VPN & ANDSF Yes

All platforms No Yes

Policy based offloading ANDSF uAxes server

Mobile IP Can be added Can be added


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References

3GPP TS 29.234 V9.2.0: 3GPP system to Wireless Local Area Network (WLAN) Interworking

3GPP TS 24.312 V11.2.0: Access Network Discovery and Selection Function (ANDSF) Management Object

(MO)

Documents

3gpp Compliancy v02