November 2001

Lars Falk, TeliaSlide 1

doc.: IEEE 802.11-01/617r1

Submission

Status of 3G Interworking

Lars Falk, Telia

November 2001

Lars Falk, TeliaSlide 2

doc.: IEEE 802.11-01/617r1

Submission

Bodies working on interworking

• ETSI BRAN• 3GPP SA1• MMAC/HiSWANa• GSM Association• IETF?• More?• Different companies offering proprietary solutions

November 2001

Lars Falk, TeliaSlide 3

doc.: IEEE 802.11-01/617r1

Submission

Two architecture alternatives

• Tight interworking• Loose interworking• See also ETSI TR 101 957

November 2001

Lars Falk, TeliaSlide 4

doc.: IEEE 802.11-01/617r1

Submission

Tight Interworking

IuIuIu

Iur

WLANUTRAN

UMTS Core Network

APCRNS RNS

APT APT

Tight interworking means that the WLAN network is connecteddirectly to the UMTS core network, via e.g. Iu or Iub

November 2001

Lars Falk, TeliaSlide 5

doc.: IEEE 802.11-01/617r1

Submission

Loose Interworking

UMTS Core Network

UTRAN

WLAN

SGSN

GGSN

ISP Network

Loose interworking means interworking is done onan IP level, e.g. between AAA and Mobile IP on one

side and HLR/HSS on the other

November 2001

Lars Falk, TeliaSlide 6

doc.: IEEE 802.11-01/617r1

Submission

Reasons for Loose Interworking

• The loose interworking avoids impact on 3G core network nodes

• Tight interworking means that full 3G signaling would have to be mapped on the WLAN radio interface, i.e. a complex solution

• Possible to support several types of WLAN• Possible to use present WLAN equipment• Tight interworking may lead to scalability

problems

November 2001

Lars Falk, TeliaSlide 7

doc.: IEEE 802.11-01/617r1

Submission

Reasons for Loose Interworking, cont’d

• Probably cheaper• Supports interworking with several types of

cellular systems• Possible to support several types of WLAN• Established in the architecture of ETSI

BRAN

November 2001

Lars Falk, TeliaSlide 8

doc.: IEEE 802.11-01/617r1

Submission

ETSI BRAN

• Loose interworking first• Phased approach, will release two stages• R1: authentication, subscriber handling,

security functions, only best effort, basic charging– Formal approval at BRAN#28 (April)

• R2: mobility support and service integration– WA: Formal approval at BRAN#30 (October)

November 2001

Lars Falk, TeliaSlide 9

doc.: IEEE 802.11-01/617r1

Submission

Some issues fromETSI TR 101 957

November 2001

Lars Falk, TeliaSlide 10

doc.: IEEE 802.11-01/617r1

Submission

High level requirements

• Support different environments (home, corporate and public) and different administrative domains

• Partnership or roaming agreements between a UMTS operator and a WLAN network shall be supported

November 2001

Lars Falk, TeliaSlide 11

doc.: IEEE 802.11-01/617r1

Submission

Subscriber data requirements

• The user can have a subscription for WLAN solely or for the combination WLAN and 3G

• The subscriber identification shall be in such a format that it can be used in just WLANs or in WLANs that are interworking with 3G systems

• The subscriber database for interworking between the WLAN and the 3G network, could be just one that is shared or there could be one for each network that share the subscribers' security association

November 2001

Lars Falk, TeliaSlide 12

doc.: IEEE 802.11-01/617r1

Submission

Security requirements

• Long list derived from a 3GPP document

November 2001

Lars Falk, TeliaSlide 13

doc.: IEEE 802.11-01/617r1

Submission

WLAN User Equipment Requirements

• It shall be possible to control access to WLAN specific data (protocol intervention).

• It shall not be possible to access WLAN specific data that is only intended to be used for security purposes.

• It shall be difficult to change the identifier.

November 2001

Lars Falk, TeliaSlide 14

doc.: IEEE 802.11-01/617r1

Submission

Mobility requirements

• Handover from WLAN to 3G and vice versa shall be supported

• A handover from WLAN to 3G will need to be service/application specific

• The user should be notified of any possible degradation of the provided quality of service due to change of access network

November 2001

Lars Falk, TeliaSlide 15

doc.: IEEE 802.11-01/617r1

Submission

QoS requirements• Should be subject to user's subscription • It should be possible for a WLAN network operator to

monitor the QoS provided to the users • It should be possible to charge a user based on the level of

QoS provided and on the QoS subscribed• QoS authorization should be performed locally• The mapping between IEEE 802.1p priority levels (0-7

bits) and IP DiffServ should be supported • It should be possible for the operator to control/configure

the mapping between IEEE 802.1p (priority bits) and DiffServ classes

November 2001

Lars Falk, TeliaSlide 16

doc.: IEEE 802.11-01/617r1

Submission

Terminal aspects

The following points should be considered:• Usage and handling of the (U)SIM, if

applicable• Communication of two mechanically

different parts, UMTS UE and WLAN MT, within a single terminal

• The placement of common functions, like handover

November 2001

Lars Falk, TeliaSlide 17

doc.: IEEE 802.11-01/617r1

Submission

Security

• Separate AAA server or integrated with HLR/HSS?

• Different alternatives for user information coordination

• User identification: NAI, IMSI or IMSI in NAI?

• UICC or not?– Telia: Support both alternatives

November 2001

Lars Falk, TeliaSlide 18

doc.: IEEE 802.11-01/617r1

Submission

Mobility and handover

• Base case: AAA roaming, i.e. reauthentication when moving to different technologies, leads to drop of actice sessions

• Enhanced mobility: e.g. via Mobile IP or SIP– Mobility only visible to upper layers, invisible

to access network

November 2001

Lars Falk, TeliaSlide 19

doc.: IEEE 802.11-01/617r1

Submission

3GPP

• SA1 will produce requirements, SA2 architecture

• One meeting held by SA1• Report should be finalised at SA1#16

(June?)• Starting point is a 5 level approach

November 2001

Lars Falk, TeliaSlide 20

doc.: IEEE 802.11-01/617r1

Submission

Levels of 3GPP SA1 approach

• Level 1 : Common billing and customer care• Level 2 : Common access control and charging

(including UTRAN level of security for WLAN)• Level 3 : Access to all UMTS PS based services• Level 4 : Service continuity between accesses• Level 5 : Seamless mobility

November 2001

Lars Falk, TeliaSlide 21

doc.: IEEE 802.11-01/617r1

Submission

What will 802.11 do?

• Study the issue within existing SG or TG?• New SG?• Wait?