RA

Numbering, Addressing and Location Identities

References: • Kaaranen, Ahtiainen, Laitinen, Naghian, Niemi: UMTS Networks – Architecture, Mobility and Services. Wiley 2001, Ch. 5.2 • 3GPP TS 23.003: Numbering, Addressing and Identification • 3GPP TS 23.002: Network Architecture (including location area definitions) UMTS Networks

Oliver Waldhorst, Jens Mückenheim

Oct-11

1

Numbering and Addressing – Summary Unique subscriber identity: – IMSI Security: temporary subscriber identity – TMSI – P-TMSI Service address and service separation: – CS: MSISDN (voice or FAX) – PS: PDP context address (IP address) Routing: – MSRN (same format as MSISDN)

UMTS Networks


Oct-11

2

User Identity: International Mobile Subscriber Identity (IMSI) IMSI is the unique identity for the mobile subscriber Maximum of 15 digits 3 digits

MCC

IMSI consists of 3 parts:

2 or 3 digits

MNC

MSIN NMSI

IMSI

IMSI serves as unique search key in the HLR, VLR, AuC and SGSN IMSI follows the ITU-T E.214 numbering plan IMSI is stored in the SIM card (USIM)

UMTS Networks


• Mobile Country Code (MCC) identifies uniquely the country of domicile of the mobile subscriber (three digits) • Mobile Network Code (MNC) identifies the home PLMN of the mobile subscriber (two or three digits) • Mobile Subscriber Identification Number (MSIN) identifies the mobile subscriber within a PLMN (9-10 digits)

Oct-11

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Service Address and Service Separation: Mobile Subscriber ISDN Number (MSISDN) MSISDN is used for service separation e.g. to separate numbers for voice and FAX CC

NDC

SN

National (significant) mobile number Mobile station international ISDN number

MSISDN consists of: • Country Code (CC) 1-3 digits • National Destination Code (NDC) 1-3 digits • Subscriber Number (SN)

MSISDN is the directory number or subscriber number MSISDN numbers are allocated from the ITU-T E.164 numbering plan Packet Data Protocol (PDP) context address is the counterpart of the MSISDN in the PS domain, e.g. an (static or dynamic) IP address UMTS Networks


Oct-11

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Subscriber Identities MSISDN ISDN Base station

Base station controller

MSC

• IMSI • MSISDN • PDP context address

GMSC

HLR AuC EIR

Node B

Radio network controller

• IMSI • MSISDN

SGSN

Internet GGSN

PDP context address UMTS Networks


Oct-11

5

Security: Temporary Mobile Subscriber Identity Number (TMSI) For security reasons, the IMSI should be transfered in non-ciphered mode as seldom as possible  TMSI is used in CS mode instead of the original IMSI  P-TMSI (Packet TMSI) is used in PS mode TMSI and P-TMSI are random numbers with limited validity time and validity area • TMSI is allocated by the VLR (changed with each UE transaction) • P-TMSI is allocated by the SGSN and valid in the SGSN area (changed when UE performs a RA update)

UMTS Networks


Oct-11

6

Routing: Mobile Subscriber Roaming Number (MSRN) • Used for routing purposes • Follows E.164 specification (similar to MSISDN number) specifies country code (CC), network (NDC), network element and subscriber number (SN)

Equipment: International Mobile Equipment Identity (IMEI) • Unique identification of the terminal hardware • IMEI is provided by UE with transaction establishment request • Use of IMEI by EIR is optional

UMTS Networks


Oct-11

7

Numbering and Addressing – Summary Unique subscriber identity: – IMSI Security: temporary subscriber identity – TMSI – P-TMSI Service address and service separation: – CS: MSISDN (voice or FAX) – PS: PDP context address (IP address) Routing: – MSRN (same format as MSISDN)

UMTS Networks


Oct-11

8

Location-related Areas Location Area (LA) – area in which a mobile station may move freely without updating the VLR Routing Area (RA) – area in which a mobile station, in PS mode, may move freely without updating the SGSN – a RA is always contained within a location area

Source: 3GPP 23.002-5.5.0 UMTS Networks

LA

RA

RA

LA/RARA Update

RA

RA

RA RA Update

RA

RA RA Update

LA/RA Update Oliver Waldhorst, Jens Mückenheim

RA

RA Update

Oct-11

9

Location-related Areas – Details MSC area – part of the network covered by an MSC – an MSC area may consist of one or several LAs VLR area – part of the network controlled by a VLR – a VLR area may consist of one or several MSC areas SGSN area – part of the network served by an SGSN – an SGSN area may consist of one or several RAs – an SGSN area may also consist of one or several BSC areas – there need not be a one to one relationship between SGSN area and MSC/VLR area Base Station Controller (BSC) area – radio coverage area (cells) controlled by a BSC – the boundaries of a BSC area and a LA are independent Radio Network Controller (RNC) area – radio coverage are (cells) controlled by a RNC – the boundaries of a RNC area and a LA are independent Cell – area of radio coverage identified by a Base station identification UMTS Networks


Oct-11

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MSC area, VLR area and SGSN area VLR SGSN

MSC SGSN

MSC

LA LA RA

RA

RA

UMTS Networks

RA

RA

RA

RA

RA

RA

RA

RA

RA

RA

RA

RA

RA RA

RA

RA

RA

RA

RA

RA

RA

RA

RA

RA


Oct-11

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Location Area Identifications Location Area Identification (LAI) MCC

MNC

LAC

LA RA

RA

RA

RA

RA

RA

RA

RA

RA

Location Area Identification

LAI elements: • Mobile Country Code (MCC) identifies the country in which the PLMN is located • Mobile Network Code (MNC) identifies the PLMN in that country • Location Area Code (LAC) identifies a location area within the PLMN (2 octets)

Routing Area Identification (RAI) LAI

RAC

Routing Area Identification

RAI elements: • A valid Location Area Identity (LAI) • Routing Area Code (RAC) identifies a routing area within a location area (1 octet) UMTS Networks


Oct-11

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Location Area Identifications UTRAN Registration Area (URA) • Location area for PS domain • RA contains a set of URAs • URA is maintained by the UTRAN

URA

URA

LA

URA

URA

RA URA

RA URA URA

URA

URA

URA

URA

URA

URA

URA

 see UTRAN part for details

Cell Global Identity (CGI) MCC

MNC

LAC

RA URA

RA URA CI

Cell Global Identity

URA

URA

URA

URA

URA

URA

URA

URA

CGI elements: • Mobile Country Code (MCC) identifies the country in which the PLMN is located • Mobile Network Code (MNC) identifies the PLMN in that country • Location Area Code (LAC) identifies a location area within the PLMN (2 octets) • Cell ID (CI) CGI is distributed to the UE by the UTRAN UMTS Networks


Oct-11

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Summary: Location Registers in UMTS Core Netw. Home Location Register (HLR) location register to which a mobile subscriber is assigned for record purposes such as subscriber information Visitor Location Register (VLR) location register for Circuit Switched (CS) services, other than the HLR, used by an MSC to retrieve information, e.g. to handle calls to or from a roaming mobile station currently located in the VLR area Location register function in the SGSN stores subscription information and location information for Packet Switched (PS) services for each subscriber registered in the SGSN (similar to VLR for CS domain) Location register function in the GGSN stores subscription information and routing information (needed to tunnel packet data traffic to the SGSN where the MS is registered) for each subscriber for which the GGSN has at least one PDP context active UMTS Networks


Oct-11

14