Transcript 3GPP/WLAN Interworking Architecture as Paradigm for NGN

3GPP/WLAN Interworking
Architecture as Paradigm for
NGN Access Independence
Rainer Liebhart, Bernhard Pfeil
Siemens mobile Networks
ETSI TISPAN – 3GPP workshop
June 22nd – 23rd, 2004
Abstract
 Access independence is one of the central requirements
in NGN standardization
 True access independence requires a generic approach,
which decouples NGN core network components and
procedures as much as possible from the subtleties of
access technologies
 3GPP is on the way to standardize with Release 6
WLAN/3GPP interworking that allows 3GPP terminals to
access a 3GPP IMS via WLAN
 The concepts of WLAN/3GPP interworking do not rely on
the specifics of the WLAN access network
 The proposal presented in this contribution is to adopt
the concepts of WLAN/3GPP interworking as the basis to
achieve true access independence in NGN
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004
Overview
 We show in the first five slides the goals, concepts and
architecture of the 3GPP/WLAN Interworking and explain
how IMS services are accessed by a 3GPP WLAN terminal:

Goals and Concepts of 3GPP/WLAN Interworking

Reference Architecture for 3GPP/WLAN Interworking

WLAN access to 3GPP IMS

IMS Registration through WLAN
 The remaining slides demonstrate how this Interworking
architecture can be used to access TISPAN-IMS services
from any access network capable to transport IP frames
(e.g. xDSL):


Access to TISPAN-IMS through generic access networks
3GPP/WLAN Interworking architecture as paradigm for
NGN access independence
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004
3GPP/WLAN Interworking: goals …
 WLAN access authentication and authorization through the mobile core
network (AAA server, HSS)
 Direct Internet access from WLAN still possible
 Common charging and billing
 Reference to standard IETF RFCs whereever possible
 (U)SIM based secure access to packet based services within the mobile
network, e.g. to the IMS, through a Packet Data Gateway (PDG) used for:
 service authentication and authorization
 IP address allocation
 policy enforcement and charging
 Roaming capable architecture
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004
… and concepts
 No dependencies on the access technology, therefore easily applicable to
other technologies like xDSL
Minimal requirements on the access network (e.g. 802.1x capable for access
authentication based on EAP-SIM/EAP-AKA)
 Access authentication is independent from service authentication: the
method used for the first one does not influence the solution for the second one
 Terminal uses standard DNS mechanisms to select appropriate PDG
(resolve PDG name or application specific name to IP address) and establishes
directly a VPN tunnel (IPSec) but can be re-directed by the network to another
PDG, if applicable (load sharing)
 VPN tunnel acts as a bridge between different address spaces (WLAN
access network, mobile core network)
 WLAN specific subscription data stored in the HSS
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004
3GPP/WLAN Interworking Architecture
from 3GPP TS 23.234
 WLAN Access
Gateway (WAG): policy
enforcement and
charging in the visited
(roaming) network
Intranet / Internet
3GPP Visited Network
3GPP AAA
Proxy
Wa
WLAN Access Network
WLAN Ww
UE
Wf
CGw/CCF
Wg
WAG
 Wa, Wd: access
authentication (AAA
protocols)
Wp
Wd
Wn
HSS
 Wi: interface to Packet
Data Networks
'/
f
W
Wo
r'
G
Wm
Wu
Wx
 Wu: VPN tunnel
between terminal and
PDG
D
3GPP AAA
Server
HLR
Packet Data
Gateway
CGw/
CCF
Wi
OCS
3GPP Home Network
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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 Packet Data Gateway
(PDG): access to packet
based services, VPN
concentrator, charging,
service authorization, IP
address allocation
© Siemens, 2004
WLAN access to 3GPP IMS
2G
3G
BSC
BTS
MSC
CS domain
2G
3G
MSC
TDM
PSTN
PLMN
GERAN
Node
B
RNC
MGW
HSS
(HLR)
(PS domain)
MRF
UTRAN
WLAN
AP
IP-Network
2G
3G
SGSN
AAA
CSCF
MGCF
WLAN
DHCP
3GPP IMS
GGSN
Access Router
DHCP
WAG
PDG
WLAN
AP
Internet
Intranet
IP address allocation, P-CSCF discovery
Service authentication and authorization
IMS signaling
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004
IMS Registration through WLAN
UE
AP
DNS
DNS
PDG
HSS
DHCP
DHCP
P-CSCF
S-CSCF
AAA HSS
1. WLAN association at L1/2
2. Access Authentication at AAA server
3. Obtain local IP address from WLAN
4. Retrieve PDG address
5. Establish tunnel to PDG
6. Obtain remote IP address and discover P-CSCF
7. Set-up security association between UE and P-CSCF
WLAN access network
8. IMS registration and session set-up
TISPAN - 3GPP workshop, June 22nd-23rd 2004
Mobile core network
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© Siemens, 2004
Access to TISPAN-IMS through generic
access networks (e.g. xDSL)
Access Network (e.g. xDSL, WLAN)
PSTN
PLMN
(local address range)
Access Router
NGN Terminal
IP Core
MGW
HSS
DHCP
AAA
PDG
MRF
CSCF
MGCF
DHCP
TISPAN-IMS
Internet
Intranet
IP address allocation, P-CSCF discovery
Service authentication and authorization
IMS signaling
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004
3GPP/WLAN Interworking architecture as
paradigm for NGN access independence
 NGN access authentication by a generic procedure, e.g. EAP based
(available for many L2 technologies)
 Access Network allocates local IP address: private or public, IPv4 or IPv6
 Access to the NGN core network is provided through the Packet Data
Gateway:
a) NGN terminal determines PDG name (application specific or a generic
one)
b) NGN terminal resolves name to IP address by standard DNS means
c) NGN terminal establishes VPN tunnel (IPSec) to PDG
d) Mutual authentication and authorization of NGN terminal and PDG
during tunnel establishment
 Assignment of remote IP address to UE by the NGN core network
 Remote address is used to perform registration in the TISPAN-IMS
 Authentication and authorization is based on NGN specific subscription data
stored in the HSS
 Most preferred solution will rely on a (U)SIM like security solution
TISPAN - 3GPP workshop, June 22nd-23rd 2004
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© Siemens, 2004