UMTS Overview
Presentation at Berkeley – Helsinki Summer
School,
May 30, 2001
Kimmo Raatikainen
Principal Scientist
Nokia Research Center
1
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Presentation Outline
• What is it?
• Standarization fora
• Radio Evolution
• UMTS Architecture
• UMTS Protocols
• QoS Issues
• Domains
• Services
• Technical Requirements
• Backup Material
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
What is it?
• IP multimedia and realtime services support within the UMTS system; IP
Multimedia network elements in addition to Packet-Switched and CircuitSwitched domains
• Two different radio access technologies connected to the same core
network: GERAN (GPRS/EDGE RAN) and UTRAN (WCDMA RAN)
–
other access technologies should be enabled as well;
e.g. fixed access, cable modems, WLAN, etc.
• Network architecture and elements based on Internet protocols
• Voice services on top of IP; Call control by SIP (or H.323 or…)
• Supports for further evolution towards even more IP-centric architecture
and services...
3
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Relevant fora
• 3G.IP - closed forum
–
Initial founding members:
Operators: AT&T, British Telecom, CSELT, Rogers Cantel, Telenor
Vendors: Nokia, Ericsson, Lucent, Nortel
–
Current member status: a lot of new members
• Mobile Wireless Internet Forum - open forum
–
Initiators: Vodafone/Airtouch, Orange, Motorola, Cisco, etc.
• Both driving for a definition of a more IP-based UMTS system and
attempting to affect standardisation bodies
4
–
3GPP - making the standards for UMTS Release 2000
–
Tiphon - IP telephony related standardisation group within ETSI
–
IETF - Internet related standards
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
3G Approaches
3GPP2
cdma2000 (IS-95+)
IS-136+
WCDMA+GSM
3GPP (GERAN)
TIA/ANSI
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
3GPP
WCDMA+GSM
3GPP2 (www.3gpp2.org)
3GPP2 Steering Committee
TSG A
Access Network Interface
TSG C
CDMA2000
TSG P
Wireless Packet Data Networking
TSG N
ANSI41/WIN
TSG S
Systems and Services Aspects
TSG R
Interface of 3GPP Radio Access Technology to 3G Core Network evolved from ANSI-41
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
3GPP (www.3gpp.org)
PCG
Karl Heinz Rosenbrock
ETSI
TSG-CN
TSG-GERAN
TSG-RAN
TSG-SA
TSG-T
Stephen Hayes
Ericsson, USA
Niels Andersen
Motorola, Denmark
Yukitsuna Furuya
NEC, Japan
Niels Andersen
Motorola, Denmark
Sang-Keun Park
Samsung, Korea
CN WG1
GERAN WG1
RAN WG1
SA WG1
T WG1
CN WG2
GERAN WG2
RAN WG2
SA WG2
T WG2
CN WG3
GERAN WG3
RAN WG3
SA WG3
T WG3
CN WG4
GERAN WG4
RAN WG4
SA WG4
CN WG5
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
SA WG5
3GPP and 3G Schedule
• First meetings held in Sophia Antipolis, France, on 7-8 December
1998
• 3GPP Releases
– ‘99 specifications on March’00
– 4 specifications on March'01
– 5 expected on December'01
• UMTS stardardisation started 1990 in ETSI (SMG 5)
• WCDMA selected as radio interface for UMTS (FDD bands) in
January 1998
– TD-CDMA selected for TDD bands
• Experimental systems already up-and-running
• Expected launch of first commercial systems in
– Japan 2001 (Tokyo area), 2003 (nation wide coverage)
– Europe 2002
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Radio Evolution
Evolution of 3G
Wide area coverage
30kHz
TDMA (IS41)
CDPD
43.2 kbits/s
GSM (MAP)
HSCSD
115.2
kbits/s
14.4 kbits/s
76.8 kbits/s
Local
EDGE
EDGE Ph. 2
GERAN
Enhanced
EDGE
473 kbits/s
473 kbits/s
Real Time IP
2Mbit/s
GPRS
5MHz
170 kbits/s
PDC/PDC-P
cdmaOne
(IS-41)
WLAN
802.11b
11 Mbits/s
9
200kHz
WCDMA
TDD
2 Mbits/s
WCDMA
FDD
WCDMA
HSPA
2
Mbits/s
10 Mbits/s
1.25MHz
cdma20001X
High Speed
Downlik
Packet
Access
TD-SCDMA
1XEV - DO, phase 2.4 Mbits/s
1 1XEV - DV,
5.4 Mbits/s
phase 2
307.2
kbits/s
Harmonise
d HL2IEEE802.11
a
IEEE802.11
standard
a
HiperLAN 2
54 Mbits/s
54 Mbits/s
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Higher
Enhanced
data rate
WLAN
WLAN
100 Mbps
Future
Wireless
UMTS Network Architecture
3G-GGSN
PS Domain
Inter-PLMN
Backbone
Network
3G-SGSN
3G-MSC
CS Domain
RNC
Node B
RAN
10
© NOKIA 2000 ICCS'00.PPT/ DATE / Juha Kalliokulju
UMTS Reference Architecture
Alternative
Access
Network
Legacy mobile
signallingNetwork
Applications &
Services *)
SCP
R-SGW *)
Mw
Ms
Mh
CAP
TE
MT
R
Um
Iu
TE
R
Uu
Mr
Mg
MRF
Gi
Gc
Gi
MGCF
Gi
Gn
Iu
MGW
MGW
Nb
Iu
T-SGW *)
Mc
GGSN
SGSN
A
UTRAN
MT
Gf
Gb
CSCF
Gi
EIR
BSS/
Iu
GERAN
Mm
Cx
HSS *)
Gr
Multimedia
IP Networks
CSCF
Mc
PSTN/
Legacy/External
Mc
Nc
MSC server
GMSC server
T-SGW *)
CAP
CAP
Applications
& Services *)
Signalling
Interface
Signalling and Data Transfer
Interface
11
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
D
C
HSS *)
R-SGW *)
Mh
*) those elements are duplicated for figure
layout purpose only, they belong to the same
logical element in the reference model
UMTS Abbreviations – 1/3
AAL2
ANSI
ARIB
ASN.1
ATM
BER
BS
BSAP
BSC
BSSGP
CC
cdma
CDPD
CN
CS
CSCF
CWTS
EDGE
ETSI
FDD
12
ATM adaptation layer 2
American National Standards Institute
Association of radio industries and businesses
Abstract Syntax Notation One
Asynchronous transfer mode
Bit error rate
Base station
Base Station application part
Base station controller
Base Station Sub-System GPRS Protocol
Call control
code division multiple access
Cellular Digital Packet Data
Core network
Circuit switched
Call services control function
China's Wireless Telecommunications Standard
Enhanced data rates for GSM evolution
European Telecommunication standardisation
institute
Frequencey division duplex
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
GERAN
Global system for mobile communications enhanced
data rates for GSM evolution radio access network
GGSN
Gateway GPRS support node
GMM
GPRS MM
GMSC
Gateway MSC
GPRS
General packet access
GSM
Global system for mobile communication
GTP
GPRS tunneling protocol
HLR
Home location register
HSCSD
High speed circuit switched data
HSS
Home subscriber server
IETF
Internet engineering task force
IM
Internet multimedia
IP
Internet protocol
ISDN
Integrated services digital network
ITU
International telecommunications union
LLC
Link layer control
MAC
Medium access control
MAP
Mobile application part
MM
Mobility management
MGCF
Media gateway control function
UMTS Abbreviations – 2/3
MGW
MPLS
MSC
MMS
MWIF
OHG
OSA
P-CSCF
PDC
PDCP
PDP
PHB
PLMN
PPP
PS
PSTN
QoS
RAN
RANAP
RF
RLC
13
Media gateway
Multiprotocol label switching
Mobile services switching center
Multimedia messaging
Mobile wireless interest forum
Operator harmonisation group
Open services architecture
Proxy-CSCF
Personal digital communication
Packet data convergence protocol
Packet data protocol
Per hop behaviour
Public land mabile network
Point-to-point protocol
Packet switched
Public switched telephony network
Quality of service
Radio access network
RAN application part
Radio frequency
Radio link control
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
RNC
Radio network controller
RRC
Radio resource control
RSVP
Resource reservation protocol
SCP
Services control point
SA
Services and System Aspects
SDL
Specification and description language
SDU
Serving data unit
SGSN
Serving GPRS support node
SGW
Signalling gateway
SM
Session managament
SMG
Special mobile group
SNDCP
Sub-network dependent convergence protocol
T
Terminal
TCP
Transmission control protocol
TD-CDMA
Time division-CDMA
TDD
Time division duplex
TDMA
Time division multiple access
TFT
Traffic flow template
TIA
Telecommunications industry association
TTA
Telecommunications technology association
TTC
Telecommunications technology committee
UMTS Abbreviations – 3/3
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TSG
Technnical specification group
UDP
User datagram protocol
UMTS
Universal mobile telecommunication system
UWCC
Universal wireless communications consortium
UTRAN
UMTS terrestrial RAN
VHE
Virtual home environment
VLR
Visitor location register
VoIP
Voice over IP
WAP
Wireless application protocol
WLAN
Wireless local area network
WCDMA
Wideband CDMA
3GPP
3rd generation partnership project
3GPP2
3rd generation partnership project 2
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Control Plane Protocols
GPRS:
Relay
SM
SM
GTP
GTP
GMM
GMM
LLC
LLC
UDP
UDP
BSSGP
IP
IP
Relay
RLC
BSSGP
RLC
MAC
MAC
Network
Service
Network
Service
L2
L2
GSM RF
GSM RF
L1 bis
L1 bis
L1
L1
MS
BSS
Um
UMTS:
SGSN
Gb
Gn
GGSN
CN protocols (Non Access Stratum, NAS)
MS
CC
RNC
BS
CN
RRM
SM
CC
MM
RRC
RRC
RLC-C
RANAP
RANAP
RLC-C
MAC
BS-RRC
MAC'
WCDMA L1
WCDMA L1
BSAP
BSAP
Transport
layers
MAC
Transport
layers
Transport
layers
Iub
Uu
15
SM
MM
RAN protocols (Access Stratum, AS)
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Transport
layers
Iu
User Plane Protocols
GPRS:
Relay
SNDCP
LLC
Relay
RLC
GTP
SNDCP
GTP
LLC
UDP/TCP
UDP/TCP
BSSGP
IP
IP
RLC
BSSGP
MAC
MAC
Frame Relay
Frame Relay
L2
L2
GSM RF
GSM RF
L1bis
L1bis
L1
L1
MS
Uu
Gb
BSS
SGSN
Gn
GGSN
3GPP:
Relay
L3CE
PDCP
GTP
GTP
GTP
UDP
UDP
UDP
UDP
IP
IP
IP
IP
L2
L2
L2
L2
L1
L1
L1
L1
PDCP
L3CE
GTP
RLC
RLC
MAC
MAC
WCDMA/
TD-CDMA
WCDMA/
TD-CDMA
MS
Uu
RAN
Iu
3G Serving Node
RAN protocols (Access Stratum, AS)
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Gn
3G
Gateway
Node
Mobile Functional Model
Mobile Phone
Point-to-Point
Data
Streaming
Browser
Messaging
Application Protocols
Socket API
QoS
Management
IP Protocols
PPP
Packet Classifier
Link Management
SM/MM
Bluetooth
WLAN
EDGE
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UMTS
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
GPRS 99
GSM CS
Data Protocol Functionality (simplified)
PDP Context 1
- IPv6 address
- Interactive QoS
PDP Context 2
- IPv6 address
- Background QoS
PDP Context 3
- IPv4 address
- Interactive QoS
Circuit
Switched
Appl.
PDCP
CC
SM
PDCP
Mgmt
Header compression
MM
(GMM)
MM
RLC-U
RRC
RLC
Mgmt
RLC-U
entity
RLC-U
entity
RLC-U
entity
RLC-U
entity
RLC-C
MAC
Transport format set
Transport format
Transport
format combination
Channel coding,
interleaving
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
WCDMA Phy
UMTS Release'99 and Release 4/5
Circuit side
WCDMA UTRAN
MSC/VLR
BS
BS
BS
BS
Iub
RNC
(optional)
Iur
RNC
WCDMA Mobile
WCDMA/VoIP
Mobile
WCDMA UTRAN
BS
BS
BS
BS
BS
BS
BS
BS
Iub
RNC
19
Packet side (GPRS)
(optional)
BSC
HLR
IP transport
option for SS7
BSC
GMSC
NEW !
Multimedia Service
Control (IPTelephony)
SCP
SGW
CSCF
MGCF
MGW
Iu
NEW !
Internet
GGSN
MSC/VLR
EDGE (GSM) BSS
EDGE/VoIP
Mobile
SCP
UMTS Release 1999
NEW ! Circuit Core
Iur
RNC
Abis
HLR
3G-SGSN
Iu
PSTN/ISDN
GMSC
3G-SGSN
GGSN
Packet Core (GPRS) with real time
services
UMTS Release 4/5
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
PSTN
/
ISDN
Internet
QoS History and Motivation
• GSM served two data types: Transparent and non-transparent
• QoS profile introduced in GPRS rel'97
– precedence class, delay class, reliability class, peak throughput
class, mean throughput class
• Enhanced QoS mechanisms in UMTS/GPRS rel'99
– multiple PDP contexts/PDP address, TFTs, management functions
• Rapid growth of Internet usage
– wide variety of applications
– emerging QoS
• Operator's requirements
– differentiation
– fast introduction of new services
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
3GPP R99/R4 standardized QoS
Different channel types
(dedicated/common)
RNC
3G-SGSN
Node B
Iu
PS Domain
AAL2
connections
Gn
DiffServ.
on transport
level IP
External QoS
mechanisms
Data Network
(Internet)
Inter-PLMN
Backbone
Network
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
3G-GGSN
Gn
IP
Firewall
21
New issues in R5:
* Interworking with
external network
(optional RSVP)
* Policy control &
bearer establishmen
(P-CSCF & GGSN)
Evolution of Mechanisms to Enable QoS
UE
RAN
SGSN
GGSN
Traffic Flow Template (TFT)
Flow label
DS code points
Source port
Destination port
Source address
SPI (Security Parameters Index for IPSec)
Protocol number
TFT
PDP context, QoS 4, signalling
PDP context, QoS 3
PDP
address
(IP)
22
PDP context, QoS 2
PDP context, QoS
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
• NSAPI
TFT
• TI
• PDP type
• PDP address
• Access point
requested
• QoS requested
• PDP configuration
options
QoS Parameters
GPRS
rel'97, '98
Precedence class
Delay class
GPRS/UMTS rel'99, 4, 5
Conversational Streaming
class
class
Allocation/retention
1, 2, 3
1, 2, 3
priority
Traffic handling
priority
Interactive
class
Background
class
1, 2, 3
1, 2, 3
1, 2, 3
Transfer delay
<100 ms
Residual BER
5*10-2…10-6
SDU error ratio
10-2…10-5
10-1…10-5
10-3…10-6
10-3…10-6
Peak throughput class Maximum bitrate
< 2048 kbps
< 2048 kbps
< 2048 kbps
< 2048 kbps
-overhead
-overhead
Mean throughput classGuaranteed bitrate
<2048 kbps
<2048 kbps
Reliability class
<250 ms
5*10-2…10-6 4*10-3…6*10-8 4*10-3…6*10-8
Maximum SDU size <=1500 octets <=1500 octets <=1500 octets <=1500 octets
Delivery order
Yes/No
Yes/No
Yes/No
Yes/No
Yes/No/-
Yes/No/-
Yes/No/-
Yes/No/-
SDU format
information
Delivery of
erroneous SDUs
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© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Interworking with Backbone Networks
Allocation/retention
priority
Traffic handling
priority
Transfer delay
mappin
g
DiffServ PHB
Expedited forwarding
Assured forwarding (some
codepoints)
Best effort
Residual BER
SDU error ratio
UMTS
Conversational
Maximum bitrate
Streaming
Guaranteed bitrate Interactive
Background
Maximum SDU size
mapping
Delivery order
SDU format
information
Delivery of
erroneous SDUs
24
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
ATM service classes
MPLS (DiffServ & other QO
schemes)
Domain definitions
25
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Domain and Subsystem Definitions
• CS CN domain: comprises all core network elements for provision of
CS services.
• PS CN domain: comprises all core network elements for provision of
PS connectivity services.
• IM CN subsystem: (IP Multimedia CN subsystem) comprises all CN
elements for provision of IM services
• Service Subsystem: Comprises all elements providing capabilities to
support operator specific services (e.g. IN and OSA)
• External Applications: Applications on an external Host.
• The Radio Access Network domain consists of the physical entities,
which manage the resources of the radio access network, and provides
the user with a mechanism to access the core network.
26
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
UMTS Service Definitions
External
Application
s
An equivalent set of
services to the relevant
subset of CS Services
IM Services
CS Services
27
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
PS Services
(IM + PS
Connectivity
Services)
PS Connectivity
Services
Service-related Definitions
• CS Services: Telecommunication services provided to
"GSM/ISDN" clients via 24.008 CC.
• PS Connectivity Services: IP connectivity service provided
to IP clients via 24.008 SM.
• IM Services: IP Multimedia Services that require support on
the Call Control level carried on top of the PS connectivity
services (this may include an equivalent set of services to
the relevant subset of CS Services).
• PS services: The superset of IM services and PS
connectivity Services.
28
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Multimedia and speech support
• SIP or H.323 instead of cellular network specific call control
–
SIP defined by IETF for IP multimedia services; to be
used in the Internet
–
H.323 defined by ITU; part of the H-protocol family; to be
used over IP networks
• Both provide session and call establishment capabilities,
among other capabilities & features
• Both probably need enhancements in order to be suitable
for the mobile network environment and cellular systems
29
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
UMTS Layered Approach for the PS
services
SCP
Legacy Mobile
Signaling
Networks
Service Layer
OSA, VHE,
etc.
CSCF
Application Layer
RSGW
CSCF
External IP
Networks
MGCF
HSS
MRF
Transport 3GSGSN
Layer
3GGGSN
TSGW
MGW
RAS
3G RAN
30
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
WLAN, DSL, Cable, etc.
PSTN/
External CS
Networks
Service Architecture
• Common service machinery for all access
systems
• A core set of basic and supplementary
services defined: e.g., call divert, barring,
pre-paid, emergency call, etc
• Open APIs (Parlay, JAIN, etc.) to support
rapid, flexible and secure service creation
to enable
– 3rd party application development
– Vendor independence
– New business models with external
service providers
• OSA service architecture to support
services
– Similar to current IN services
– Exploiting the enhanced capabilities of
IP network (video, multimedia etc.)
• Globally accessible services via
CAMEL/WIN or by direct access between
terminal
and application server
31
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Application
Servers
Framework
Server
Other Service
Capability Servers
OSA
Parlay/Corba/IP
1
Short message
service center
WAP
Server
2
HSS
Web
Server
SCP
Service Capability Servers:
1) Message Transfer
2) Call Control
CSCF
Multi-layered Approach to Mobility
Micro
Mobility
Access
Mobility
(1)
3G-SGSN
Edge
Network
HSS
CSCF
3G-GGSN
RAN
IPv4
Edge Router/
Firewall
3G-SGSN
Access
Mobility
(2)
Network
Level
Mobility
Edge
Network
WLAN
Network
Level
Mobility
32
IPv6
Edge Router/
Firewall
3G-GGSN
IPv6
Network
MGCF/
MGW
RAS
DSL
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
RAS
Cable
RAS
(public
or
private)
(public
or
private)
PSTN
Technical Requirements
• Equal or better quality for voice transmission
• Backwards compatibility vs. revolution (e.g. old phones should work in
the new networks due to the large installed customer base)
• Roaming to/from legacy and UMTS R99 networks should be possible
• Interworking necessary with telephony networks, GSM & other cellular
networks, IP networks, etc.
• Realtime handovers: which cases must be supported? Intra RAN, inter
RAN, inter-SGSN, inter-operator, inter-GGSN, inter-system, ...
• Easy service creation and execution environment. Possible
components:
–
33
Mobile Station Execution Environment (MExE), SIM Application
Toolkit (SAT), Open Service Architecture (OSA), Virtual Home
Environment (VHE), CAMEL, WAP, etc.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Technical Key Issues
• Call control protocol: SIP (or H.323 or …)
• Addressing & Identifiers
• Roaming models and handovers
• Legacy networks: roaming, handovers, etc.
• New header compression algorithms, especially suited for
realtime traffic: IETF ROHC
• End-to-end QoS negotiation? Enough guarantees on the
call quality? Role of RSVP?
• IP version to be used
• Etc etc…
34
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Requirements for Future All-IP Systems – 1/2
• Mobility Handling
– Determined by, and optimised for, mobile terminals
• Multiservice
– Common Network for real time and non real time services
– Rapid, flexible and easy creation of new services
• Layered Network Functionality
– For independence of access, transport, applications and
service creation
– For system flexibility and future evolution
• Multiaccess & Access Independence
– Several accesses including WCDMA, EDGE, WLAN, Cable
etc.
– Mobility between accesses (Global IP Mobility)
35
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Requirements for Future All-IP Systems – 2/2
• IPv6-Based
–
For scalability and address space
–
For mobility between accesses (Global IP mobility)
• Evolution and Legacy Support
–
For utilisation of existing investments
–
For service continuity
• Shared Transport and Network Management
–
36
For cost efficiency
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Background Material
37
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: Call State Control
Function (CSCF)
• Logical, i.e. internal, components:
•
ICGW (Incoming call gateway): Acts as a first entry point and performs routing of
incoming calls, Communicates with HSS, Incoming call service triggering (e.g. call
screening/call forwarding unconditional) may need to reside for optimisation purposes,
Query Address Handling (implies administrative dependency with other entities),
Communicates with HSS
•
CCF (Call Control Function): Call set-up/termination and state/event management,
Interact with MRF in order to support multi-party and other services, Reports call events
for billing, auditing, intercept or other purpose, Receives and process application level
registration, Query Address Handling (implies administrative dependency), May provide
service trigger mechanisms (service capabilities features) towards Application & services
network (VHE/OSA), May invoke location based services relevant to the serving network,
May check whether the requested outgoing communication is allowed given the current
subscription.
SPD (Serving Profile Database): Interacts with HSS in the home domain to receive
profile information for the R00 all-IP network user and may store them depending on the
SLA with the home domain, Notifies the home domain of initial user’s access (includes e.g.
CSCF signalling transport address, user ID etc. needs further study), May cache access
related information (e.g. terminal IP address(es) where the user may be reached etc.)
AH (Address Handling): Analysis, translation, modification if required, address
portability, mapping of alias addresses, May do temporary address handling for internetwork routing.
•
•
38
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: Home Subscriber
Server
• The Home Subscriber Server (HSS) is the master database for a given user. It is
responsible for keeping a master list of features and services (either directly or
via servers) associated with a user, and for tracking of location of and means of
access for its users. It provides user profile information, either directly or via
servers. It is a superset of the Home Location Register (HLR) functionality, The
HSS shall support a subscription profile which identifies for a given user for
example:
-
1) user identities; 2) subscribed services and profiles; 3) service specific
information; 4) mobility management information; and 5) authorization
information
• Like the HLR, the HSS contains or has access to the authentication
centers/servers (e.g. AUC, AAA).
• HSS structure:
39
–
User Mobility Server (UMS): it stores Service Profile for the Multimedia
domain and stores Service Mobility or Serving CSCF related information for
the users. UMS might also generate, store and/or manage security data and
policies (e.g. IETF features). UMS should provide logical name to transport
address translation in order to provide answer to DNS queries.
–
3G HLR: A UMTS HLR enhanced to support Release 2000 access specific
information.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: HSS structure
HOME SUBSCRIBER SERVER
USER MOBILITY SERVER
3G HLR
AAA
Location Server
(e.g. LDAP)
D
Cx
Gc
C
MSC Server
40
GMSC Server
Gr
SGSN
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Mh
GGSN
R-SGW
CSCF
DNS
Functional Elements: Transport
Signalling Gateway
• This component in the Rel 4/5 network is PSTN/PLMN
termination point for a defined network.
41
–
Maps call related signalling from/to PSTN/PLMN on an IP
bearer and sends it to/from the MGCF.
-
Needs to provide PSTN/PLMN <-> IP
address mapping.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
transport level
Functional Elements: Roaming
Signalling Gateway
• The role of the R-SGW described in the following bullets is
related only to roaming to/from 2G/R99 CS and GPRS
domain to/from R00 UMTS Teleservices domain and UMTS
GPRS domain and is not involving the Multimedia domain.
42
-
In order to ensure proper roaming, the R-SGW performs the signaling
conversion at transport level (conversion: Sigtran SCTP/IP versus
SS7 MTP) between the legacy SS7 based transport of signaling and
the IP based transport of signaling. The R-SGW does not interpret the
MAP / CAP messages but may have to interpret the underlying SCCP
layer to ensure proper routing of the signaling.
-
(For the support of 2G / R99 CS terminals): The services of the
R_SGW are used to ensure transport interworking between the SS7
and the IP transport of MAP_E and MAP_G signalling interfaces with
a 2G / R99 MSC/VLR
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: Media Gateway
Control Function
• This component is PSTN/PLMN termination point for a
defined network.
43
-
Controls the parts of the call state that pertain to connection control
for media channels in a MGW.
-
Communicates with CSCF.
-
MGCF selects the CSCF depending on the routing number for
incoming calls from legacy networks.
-
Performs protocol conversion between the Legacy (e.g. ISUP, R1/R2
etc.) and the R00 network call control protocols.
-
Out of band information assumed to be received in MGCF and may
be forwarded to CSCF/MGW.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: Media Gateway
• This component is PSTN/PLMN transport termination point for a defined
network and interfaces UTRAN with the core network over Iu.
• A MGW may terminate bearer channels from a switched circuit network
and media streams from a packet network (e.g., RTP streams in an IP
network). Over Iu MGW may support media conversion, bearer control
and payload processing (e.g. codec, echo canceller, conference bridge)
for support of different Iu options for CS services: AAL2/ATM based as
well as RTP/UDP/IP based.
-
Interacts with MGCF, MSC server and GMSC server for resource control;
Owns and handles resources such as echo cancellers etc.; May need to have
codecs.
• Tailoring (i.e packages) of the H.248 may be required to support
additional codecs and framing protocols, and support of mobile specific
functions
44
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: Multimedia
Resource Function
• This component:
45
-
performs multiparty call and multimedia conferencing functions. MRF
would have the same functions of an MCU in an H.323 network.
-
Is responsible for bearer control (with GGSN and MGW) in case of
multi party/multi media conference
-
may communicate with CSCF for service validation for
multiparty/multimedia sessions.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Functional Elements: (G)MSCs, (G)MSC
servers
• MSC server: comprises the call control and mobility control parts of a
GSM/UMTS MSC and is responsible for the control of mobile originated
and mobile terminated CS Domain calls. It terminates the user-network
signalling (04.08+CC+MM) and translates it into the relevant network –
network signalling. The MSC Server also contains a VLR to hold the
mobile subscriber's service data and CAMEL related data.
• MSC server controls the parts of the call state that pertain to connection
control for media channels in a MGW.
• Gateway MSC Server: The GMSC server mainly comprises the call
control and mobility control parts of a GSM/UMTS GMSC.
• MSC: A MSC server and a MGW make up the full functionality of a MSC
as defined in 23.002
• Gateway MSC: A GMSC server and a MGW make up the full
functionality of a GMSC as defined in 23.002
46
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Release 5:
Basic IMS
Configuration
IP Multimedia
Networkds
PSTN
Legacy mobile
signalling Networks
CSCF
Mk
Mm
Mw
T-SGW
R-SGW
BGCF
Mj
MGW
Mi
MGCF
Mc
Ms
Mh
CSCF
Mg
Cx
HSS
Mr
MRF
IM Subsystem
Gi
47
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Gi
Gi
Gi
Proxy-CSCF
• Proxy-CSCF (P-CSCF) is the first contact point within the IM subsystem. Its
address is discovered by “Procedures related to Local CSCF Discovery ”. The
P-CSCF behaves like a proxy (as defined in RFC2543). The functions
performed by the P-CSCF are:
–
Forward the SIP register request received from the UE to an I-CSCF
determined using the home domain name, as provided by the UE.
–
Forward SIP messages received from the UE to the SIP server (e.g. SCSCF) whose name the P-CSCF has received as a result of the registration
procedure.
–
As part of processing of the request and before forwarding, the P-CSCF may
modify the Request URI of outgoing requests according to a set of
provisioned rules defined by the network operator (e.g. Number analysis and
potential modification such as translation from local to international format.)
–
Forward the SIP request or response to the UE.
–
Detect an emergency call and select a S-CSCF in the visited network to
handle emergency calls.
–
The generation of CDRs.
Authorization of bearer resources and QoS management and Security
areMikkoFFS.
© 2001 NOKIA issues
Kimmo Raatikainen,
Puuskari, Juha Kalliokulju, Sami Uskela
–
48
Interrogating-CSCF
• Interrogating-CSCF (I-CSCF) is the contact point within an operator’s network
for all connections destined to a subscriber of that network operator, or a
roaming subscriber currently located within that network operator’s service area.
There may be multiple I-CSCFs within an operator’s network. The functions
performed by the I-CSCF are:
• Registration: Assigning a S-CSCF to a user performing SIP registration (see
section on Procedures related to Serving CSCF assignment); Cryptography
mechanisms may be used by I-CSCF to hide the S-CSCF when S-CSCF name
is provided to the P-CSCF in the Visited network
• Session Flows: Route a SIP request received from another network towards the
S-CSCF; Obtain from HSS the Address of the S-CSCF; Forward the SIP
request or response to the S-CSCF determined by the step above;
• Charging and resource utilisation: Generation of CDRs.
• In performing the above functions the operator may use I-CSCF to hide the
configuration, capacity, and topology of the its network from the outside
• Editor’s Note: Additional functions related to inter-operator security are for
further study.
49
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Serving-CSCF
• Serving-CSCF (S-CSCF) performs the session control services for the endpoint.
It maintains session state. Within an operator’s network, different S-CSCFs may
have different functionalities. The functions performed by the S-CSCF during a
session are:
• Registration: Acts like a Registrar defined in the RFC2543, i.e. it accepts
Register requests and makes its information available through the location
server (eg. HSS).
• Session flows: Session control for the registered endpoint's sessions; Interaction
with Services Platforms for the support of Services;
–
On behalf of an originating endpoint (i.e. the originating subscriber/UE);
Forward the SIP request or response to the I-CSCF
–
On behalf of a destination endpoint (i.e. the terminating subscriber/UE):
Forward the SIP request or response to a P-CSCF for a MT session to a
home subscriber within the home network, or for a subscriber roaming within
a visited network where the home network operator has chosen not to have
an I-CSCF in the path; Forward the SIP request or response to an I-CSCF
for a MT session for a roaming subscriber within a visited network where the
home network operator has chosen to have an I-CSCF in the path.
• Charging and resource utilisation: Generation of CDRs.
• Security issues are FFS
50
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
BGCF
• The S-CSCF, possibly in conjunction with an application server, shall determine
that the session should be forwarded to the PSTN. The S-CSCF will forward the
Invite information flow to the BGCF in the same network.
• The BGCF selects the network in which the interworking should occur based on
local policy
• If the BGCF determines that the interworking should occur in the same network,
then the BGCF selects the MGCF which will perform the interworking, otherwise
the BGCF forward the invite information flow to the BGCF in the selected
network. The MGCF will perform the interworking to the PSTN and control the
MG for the media conversions.
Receipt of SIP
invite
S-CSCF determines if
the session is to be continued in IM CN
or in GSTN?
Continued via
IM CN subsystem
To GSTN via Network
Other network
BGCF selects network
Same network
Continue with
SIP routing
51
BGCF forwards
signalling to
the selected
network
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
BGCF selects &
forwards
the signalling
to the MGCF
Identities
• Private User identities
-
Every IM subsystem subscriber shall have a private user identity. The private
identity is assigned by the home network operator, and used, for example,
for Registration, Authorization, Administration, and Accounting purposes.
This identity shall take the form of a Network Access Identifier (NAI) as
defined in RFC2486. Note: It is possible for a representation of the IMSI to
be contained within the NAI for the private identity.
-
The Private User Identity is not used for routing of SIP messages
• Public user identities
52
–
Every IM subsystem subscriber shall have one or more public user identities
[Ref 22.228]. The public user identity/identities are used by any user for
requesting communications to other users. Note: For example, this might be
included on a business card.
–
Both telecom numbering and internet naming schemes can be used to
address users depending on the Public User identities that the user’s have.
–
The public user identity/identities shall take the form of SIP URL (as defined
in RFC2543 and RFC2396) or E.164 numbers.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
New Reference points (1)
• Cx Reference Point (HSS – CSCF): the transfer of data between
the HSS and the CSCF. When a UE has registered with a CSCF, the
CSCF can update its location towards HSS. This will allow the HSS to
determine which CSCF to direct incoming calls to. On this update
towards the HSS, the HSS sends the subscriber data (application
related) to CSCF. For a MT call, CSCF asks the HSS for call routing
information.
• Gm Reference Point (CSCF – UE): allow UE to communicate
with the CSCF e.g.
53
-
Register with a CSCF,
-
Call origination and termination
-
Supplementary services control
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
New reference points (2)
• Mc Reference Point (MGCF – MGW): describes the interfaces between
the MGCF and MGW, between the MSC Server and MGW, and between
the GMSC Server and MGW. It has the following properties:
54
-
full compliance with the H.248 standard.
-
flexible connection handling which allows support of different call models
and different media processing purposes not restricted to H.323 usage.
-
dynamic sharing of MGW physical node resources. A physical MGW can be
partitioned into logically separate virtual MGWs/domains consisting of a set
of statically allocated Terminations.
-
dynamic sharing of transmission resources between the domains as the
MGW controls bearers and manage resources according to the H.248
protocols.
–
The functionality across the Mc reference point will need to support mobile
specific functions such as SRNS relocation/handover and anchoring. It is
expected that current H.248/IETF Megaco standard mechanisms can be
applied to enable this.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
New reference points (3)
• Mg Reference Point (MGCF – CSCF): The Mg reference point is based
on external specifications, e.g. H.323 or SIP
• Mh Reference Point (HSS – R-SGW): supports the exchange of mobility
management and subscription data information between HSS and R99
and 2G networks. This is required to support Release 2000 network
users who are roaming in R99 and 2G networks.
• Mm Reference Point (CSCF – Multimedia IP networks): an IP interface
between CSCF and IP networks. This interface is used, for example, to
receive a call request from another VoIP call control server or terminal.
• Mr Reference Point (CSCF - MRF): Allows the CSCF to control the
resources within the MRF.
• Ms Reference Point (CSCF – R-SGW): This is an interface between the
CSCF and R-SGW.
55
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
New reference points (4)
• Mw Reference Point (CSCF – CSCF): The interface allows one CSCF
(e.g. home CSCF) to relay the call request to another CSCF (e.g.
serving CSCF).
• Nc Reference Point (MSC Server – GMSC Server): Over the Nc
reference point the Network-Network based call control is performed.
Examples of this are ISUP or an evolvement of ISUP for bearer
independent call control (BICC). In the R’00 architecture different
options for signalling transport on Nc shall be possible including IP.
• Nb Reference Point (MGW-MGW): Over the Nb reference point the
bearer control and transport are performed. The transport may be
RTP/UDP/IP or AAL2 for transport of user data. In the R00 architecture
different options for user data transport and bearer control shall be
possible on Nb, for example: AAL2/Q.AAL2, STM/none, RTP/H.245.
56
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
New
reference
points
(5):
CAP
towards
ch Center
SCP
meHere
TypeDateHere
• This includes the interfaces from the SGSN to the SCP, from
the MSC Server to the SCP, and the GMSC Server to the
SCP.
57
M3UA
SCTP (1)
CAP
TCAP
SCCP
MTP-3B
SAAL
IP (2)
ATM(2)
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
Narrow-band SS7
STM (2)
New reference points (6): MAP-based
• This includes the interfaces from the GGSN to the HSS (Gc
reference point), from the SGSN to the HSS (Gr reference
point), from the GMSC Server to the HSS (C reference
point), and the MSC Server to the HSS (D reference point).
• The MAP based interfaces may be implemented using MAP
transported over IP, or MAP over SS7.
• MAP can be transported on the same protocol stacks as
CAP
58
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela
New reference points (7): Iu ref point
• This is the reference point between UTRAN and the R00
core network. This reference point is realized by one or
more interfaces:
59
-
Between UTRAN and SGSN, transport of user data is IP based.
-
Between UTRAN and SGSN, transport of signalling is based on IP or
SS#7.
-
Between UTRAN and MGW, transport of user data is based on
different technologies (e.g., IP, AAL2), and includes the relevant
bearer control protocol in the interface.
-
Between UTRAN and MSC server, transport of signalling is based on
IP or SS#7.
• When the Iu_cs is ATM based, then the protocols used can be based on
R99 protocols or an evolved version. When Iu_cs is IP based, new IP
transport related protocols need to be added as part of the Iu protocols.
It shall be possible to have R99 Iu interface with MSCs compliant to R99
specifications in the network. It shall be possible to have a R99 CS
domain with R99 Iu_cs reference point coexisting with a R00 Iu
reference point.
© 2001 NOKIA Kimmo Raatikainen, Mikko Puuskari, Juha Kalliokulju, Sami Uskela