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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Prof. Dr. Thomas Magedanz
Technical University of Berlin / Fraunhofer FOKUS
(magedanz@fokus.fraunhofer.de)
Service Delivery Platforms for Fixed Mobile Convergence (FMC)
- An Overview of the ETSI TISPAN NGN and theIP Multimedia Subsystem (IMS)
Tutorial @ SATNAC, Stellenbosch, South Africa, September 4th, 2006
2
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Abstract
This tutorial provides a technical overview of the architecture,components and protocols of the emerging ETSI TISPAN Next Generation Network (NGN) and the 3GPP IP Multimedia Subsystem (IMS) / 3 GPP2 Multimedia Domain (MMD) which provides the technological basis for the provision of seamless IP based multimedia services on top of converging networks. This tutorial looks at the driving forces for the NGN / IMS architecture definition, introduces the key signalling and control protocols of all IP networks (i.e., SIP and Diameter) forming the basis for NGN/IMS component interactions, and explains the key NGN/IMS elements and their interactions.Special attention will be given to the NGN/IMS application server options, namely CAMEL, OSA/Parlay and SIP AS.The tutorial ends with an overview of the FOKUS IMS play ground (www.fokus.fraunhofer.de/ims).
Page 2
3
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
The Presenter
Prof. Dr. Thomas MagedanzThomas Magedanz (PhD) is professor in the electrical engineeringand computer sciences faculty at the Technical University of Berlin, Germany, leading the chair for next generation networks (Architektur der Vermittlungsknoten – AV). In addition, he is director of the “3G beyond” division at the Fraunhofer Institute FOKUS, which also provides the national 3G beyond test and development centre in Germany. He is senior member of the IEEE, editorial board member of several journals, and the author of more than 120 technical papers/articles. He is the author of two books on IN standards and IN evolution. Based on his 15 years of experience in the teaching complex IT and telecommunication technologies to different customer segments inan easy to digest way, Dr. Thomas Magedanz is a globally recognised technology coach. He regularly provides strategic andtechnology briefings for major operators and telecom vendors, aswell he acts often as invited tutorial speaker at major telecom conferences and workshops around the world.
4
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Contact
Prof. Dr.-Ing. habil Thomas Magedanz
TUB Chair Next Generation Networks / Director FOKUS 3Gb Division
magedanz@fokus.fraunhofer.de+49 171 172 70 70+49 30 3463 7229 Kaiserin Augusta-Allee 31
14513 Berlin, Germany
Page 3
5
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Q&A
6
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Evolution towards Converged Networks
ConvergedNGN
HomeNetworks
CableNetworks
FixedNetworks
PSTN
ISDN
DSL
FMCGSM
MobileNetworks
AnalogueGPRS UMTS HSDPA
UMA
WiFi WiMax
Internet
FTP email WWWIMP2P
PortalsIPTVVoIP
SMS WAP
TriplePlay
Web2.0
ContentSharing
VoD
Broadcast
iTV
IT
Page 4
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Convergence of Networks, Services, Applications
MobileNetwork
FixedNetwork
HomeNetworkEnterprise
Network
Fixed MobileConvergence
Mobile Enterprise Home Entertainment
Business
Connection
(IP Centre
x)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Fixed Mobile Convergence
Page 5
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
The traditional Telco Value Chain is changing
The industry structure changes. New players have successfully entered thescene. Equipment and handset manufacturers additionally drive the market.
10
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Triple Play brings new Players in the Market
• Among traditional networkoperators (CATV / Telco) newplayers (i.e. equipmentmanufacturers and serviceproviders) have joined the racefor multimedia / triple playrevenues.
• Purpose of value creation aroundbasic communication services ismostly to maintaincompetitiveness and profitability
• Increasing competitive pressuredrives the transformation of theTelco industry.
Page 6
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Time
Revenue
Community Support is one of the most
promising solutions to boost profits in NGNs
Declining voice
revenues
Looking for new NGN applications
Voice over IP (VoIP) IP CentrexMessaging/
PresenceHome
EntertainmentMultimedia Conference
…
12
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
War is not on networks, it is on services !
• Network access becomes a commodity
• „Always on“ is getting real• Market entry barriers for services vanish
• Content and Services as overlay
• Value Chain splits horizontally• Clear & present threats for operators
• losing VAS revenues
• losing subscriber ownership
• losing control over the Mobile Value Chain
?
Page 7
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Pre-FMC = 3GPP Virtual Home Environment
Virtual Home Environment: VHESystem Concept forPersonalized Service
portability across Network and Terminals boundaries
portabilityacross terminal
boundaries
portabilityacross network
boundaries
Call Forwarding: 08:00-18:00 -> ..18:00-08:00 -> ..
Lotto by WAPFootball by VRestaurantxx
Personal ServiceEnvironment
Xxzz
14
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IP domainCircuit-Switched domain
TraditionalCS
Co-existence All IPWorld
UniformService Delivery Platform
Network Convergence
Seamless Services Data ServicesVoice Services
Page 8
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Q&A
16
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Multi-Service, Multi-Access networks
All IP
Page 9
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Internet Control vs. Telecommunications Control
CentralControl
USER USER
CentralControl
CentralControl
SW SW SWSW SW SW
UNI NNI NNI UNI
ITU Intelligent Network Control: POTS, ISDN, BISDN, FR, ATM, H.323, MEGACO/H.248, GSM
Services supported by interfaces and central controllers
User has little control
USER USER
ElectiveServer
ElectiveServer
Internet
“Dumb Network”
R
R
R
User has control of all applications and choice of servers
All services enabled by protocols: From ftp to web
No single point of failure
R
18
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Next Generation Network 3 Tier Architecture
• Enhanced services for the next generation network will be enabled by a tiered architecture where “Application Servers” will provide an independent service layer for the execution of enhanced services and content
• Session / Call Control based on advanced signaling protocols (i.e. SIP) is performed in Softswitches, or “Session Servers”
• Transport of signaling and content (incl. Voice) data will be done by Routers in the classical IP fashion. Dedicated nodes, i.e. “Media Gateways” and “Media Servers” are in charge for processing content data controlled by the Call Servers.
SessionServers
Media ServersRouters
ApplicationServer
Page 10
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Next Generation All IP Reference Architecture
SessionControl
Function
SessionControl
Function
ApplicationServer
Function
MediaGatewayFunction
SIP SIP
SignalingGatewayFunction
•Basic call control•Signaling•Resource Management•CDR Generation
•IVR•Conferencing•Facsimile•Speech Recognition•Text-to-Speech
•Service Execution•Service Management•Service Creation
Bearer dataTransfer
SS7/IP SignalingConversion
SIP
SIP
SubscriptionServer
Function
DiameterDiameter
AAA: User and Appl Profiles
Connection / call control functions
Application control functions
SIP
RTP MediaServer
Function
SIP
Note that there are many other IETF protocols used as well, e.g. SDP, Megaco, SCTP, RTCP, MSRP, XCAP, etc.
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
The NGN Definition
Page 11
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
NGN Global standards cooperation
Internet Engineering Task ForceInternet Engineering Task ForceDefines SIP, SDP and other protocols underlying IMS
IMS is driving some of the work in IETF
3rd Generation Partnership Project3rd Generation Partnership Project3rd Generation Partnership Project23rd Generation Partnership Project2Define IMS network elements and infrastructure
Harmonization effort has kept definitions as similar as possible
Open Mobile AllianceOpen Mobile AllianceDefining IMS services, e.g. Instant Messaging, Push-to-TalkNot strictly mobile oriented, driving wireline services also
The Parlay GroupThe Parlay GroupIntegral to IMS architecture, define standard API frameworks
American National Standards InstituteAmerican National Standards InstituteT1.679 covers interworking between ANSI ISUP and SIP
International Telecommunication UnionInternational Telecommunication UnionQ.1912.SIP covers interworking between ITU-T ISUP and SIP
H.248 for media control
ToolsTools
Services
Services
LegacyLegacy
TISPA
N
TISPA
N –– ETS
I bo
dy o
n N
ext G
en
eratio
n N
etw
ork
ETSI b
od
y o
n N
ext G
en
eratio
n N
etw
ork
Ag
ree
me
nt o
n re
use
of 3
GP
P/3
GP
P2
IMS
in co
mp
reh
en
sive
NG
N p
lan
s
Allia
nce fo
r Teleco
mm
un
icatio
ns In
du
stry So
lutio
ns
Allia
nce fo
r Teleco
mm
un
icatio
ns In
du
stry So
lutio
ns
Ne
arin
g a
gre
em
en
t to u
se 3
GP
P/3
GP
P2
IMS
CJK
Ch
ina Ja
pan
Ko
rea
CJK
Ch
ina Ja
pan
Ko
rea
Sta
rting
Focu
s Gro
up
on
NG
N
ITUITU
-- T NG
N Fo
cus G
rou
pT N
GN
Focu
s Gro
up
Lev
era
gin
g IM
S in
wire
line
Wireline &Wireline &
ConvergedConverged
NGN NGN
Architectures
Architectures
Archite
cture
Archite
cture
Wireless
Driven
Wireless
Driven
Building the NGN through Cooperation between many Standards players (incl. DSL, MSF, TMF …): leading to convergence
22
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
3GPP IP Multimedia Subsystem (IMS)• The IMS was originally standardised by 3GPP as part of UMTS Release 5
– Basic VoIP, IM, Presence support on top of GPRS– Adaptations to “real word” have been made in Release 6 (QoS, PoC support)– Release 7 will look at unified IMS for all IP access networks (DSL, WLAN, etc.)
• The IMS is based on the IP world protocols, namely – SIP (Session Initiation Protocol) for Session Control, and – Diameter for AAA (Authentication, Authorisation & Accounting)– plus many others, i.e. SDP, RTP, RTCP, MGCP, etc.
• Key components of the IMS architecture are– Extended AAA Server (Home Subscriber System – as evolution of the HLR)– SIP servers / soft switches– Media Servers & Media Gateways– and Application Servers
Page 12
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS 3GPP Evolution
• IMS brainstroming started in Release 4, without real specs.• IMS Release 5 is the first complete specification of IMS finished in
2003 (but based on some unrealistic assumptions;-( )• Key features of IMS Release 5:
– IMS Architecture: IMS Architecture, network entities, reference points (interfaces) between the network entities.
– User Identities: Public/Private User Identity, usage of the SIP-URI and TEL-URI, ISIM, the use of the USIM instead of the ISIM.
– IMS Session Control: IMS Registration, IMS Session Routing, Session-Modification and Teardown, SIP Signaling Compression.
– IMS Service Control: invocation/control of IMS Application Servers based on Filter Criteria in the CSCF. IM-SSF and there-use of CAMEL Services. Interconnect with the OSA-GW and the use of OSA services.
– QoS Mechanisms: QoS Preconditions, QoS/Media Authorization based on the PDF.
– Security Mechanisms: IMS User Authentication, Message Integrity Protection, IMS Network Domain Security.
24
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS 3GPP Release 6
• Release 6 adapted IMS to the real world (i.e. lack of IMS SIM cards, IPv6 deployment, competing PoC standards), etc.) and was finished end of 2005
• Key Features defined in Rel-6 IMS:– IMS Interworking: IMS Interworking to the CS-Domain (more details for CS and
PSTN), Interworking with SIP Clients in the Internet (IPv4/v6 Interworking), WLAN access to the IMS (not completed)
– IMS Session Control: multiple registrations, routing of group identities.– Security Mechanisms: confidentiality protection of SIP messages, use of public
key infrastructure, Ut-interface security, early IMS security– IMS Services: Presence, Instant Messaging, Conferencing, group management.
Page 13
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
S-CSCF
IMS Layers: Transport, Session Control, Apps
P-CSCF S-CSCF
HSS(AAA)
I-CSCF
MediaGateway
SGW, MGCF, MGF
ApplicationServer IMS enabler
Group Mgt
Access Networks(WLAN, UMTS, DSL)
Interworking withLegacy Networks(GSM, ISDN, DVB)Underlying IP Core Network
IMS Core System
IMS Service Framework
MediaServer
MFRC + MFRP
IMS enablerPresence
Note: IMS Charging Architecture is not reflected on this slides = Diameter Interfaces to many entities
26
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Major Components
• The IMS is an Overlay Session/Service Control architecture on top of the packet domain (GPRS, UMTS, WLAN, DSL) based on IP technologies and IETF protocols(e.g. SIP, Diameter):
– IMS Core• S-CSCF (Serving Call Session Control Function) the IS anker point in the home
network• I-CSCF (Interrogating Call Session Control Function) providing topology hiding• P-CSCF (Proxy Call Session Control Function) Entrypoint into IMS world• MS (Media Server) – Media Server hosting special resources• MGF (Media Gateway) for Interworking with legacy networks• PDF (Policy Decision Function) for QoS Control using Polícies (COPS)
– IMS Application Layer• HSS (Home Subscriber System) for maintaining subscriber and AS profiles• AS (Application Server Function) for hosting applications• IMS enablers (e.g. Presence, Group Mgt.) are specific ASs with generic functions
– And the IMS end system (IMS Client) plays an important role real multimedia / IMS services
Page 14
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
3GPP2 Multimedia Domain (MMD)• 3GPP2 MMD is a reference architecture model for cdma2000 family
based wireless core network• Main specifications:
- “All-IP Core Network Multimedia Domain: Overview”– http://3gpp2.org/Public_html/specs/X.S0013-000-0_v1.0_022604.pdf
- “IP Network Architecture Model for cdma2000 Spread Spectrum Systems”http://3gpp2.org/Public_html/specs/S.R0037-– http://3gpp2.org/Public_html/specs/S.R0037-0_v3.0_111303.pdf
• based on IP protocols, elements and principles• Main protocols are (IETF’s) SIP, DIAMETER and Mobile IP• Consists of:
– Packet Data Subsystem (PDS): supports general packet data service– IP Multimedia Subsystem (IMS): provides multimedia session capabilities
28
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
MS
AccessNetwork
PDS
IMS
PSTN
Internet
MMD Core Network Architecture Model
IMS&PDS
AS
CSCF
MRFCMGCF
MRFPIM-MGW
AAA
DB‘s
AccessGateway
MIP HABorderRouter
BearerSignaling
Signaling&Bearer
Page 15
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
3GPP2 vs. 3GPP
Through a Position Server and Position Determining Entity (PDE)
Through Sh interfaceLocation information
Not defined yetDefined between PDF & GGSNGo interface May change even during a sessionAllocated prior to registration Anchored GGSN/PDSN
P-CSCF and PDSN (Packet Data Service Node == GGSN) may be in different network
P-CSCF and GGSN are in the same network
P-CSCF location
Configuration and security stored in the IMS terminal or in R-UIM (Removable User Identity Module)
Defined a UCC (USIM or ISIM)Smart card
Not defined, since there is no CAMELBetween HSS and IM-SSF (CAMEL)Si interface
No support of PDP contextThrough PDP context activation and DHCP
P-CSCF discoveryEVRC and SMVAMRSpeech codec
Database only, separated AAADatabase and AAAHSSIPv6IPv4 and IPv6IP versionMobile IPGPRS tunnelingMobility management
3GPP23GPPFeature
30
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
ETSI TISPAN
Page 16
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Target NGN
NGN Infrastructure Evolution (CS PS)
PSTNPSTNEmulationSubsystem
PSTNSimulation
Full PSTN Feature Transparency=> Secondary NGN objective
SIP (IMS) Services & Architecture=> Primary NGN objective
IMS“SIP” services
Evolution to NGN
“Perfect Simulation”
32
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
ETSI TISPAN NGN Releases
Release 1: A tough Job under significant market pressure
• Release 1 bringing Multimedia services0 Terminology, Strategy, QoS, Security, NNA & Identification, ENUM1 Requirements, General architecture, Early services and protocols2 Detailed architecture, Specific services and protocols, 3GPP interface endorsements, testing 3 Operations Support Systems, Congestion control, NGN user data, Single sign-on, PSTN/ISDN
emulation• Release 2 optimizing access resources usage
– According to user subscription profile and service use– Corporate users specific requirements …
• Release 3– Full mobility, Streaming Subsystem, TV Broadcasting Subsystem?
2006
Release 3
2007 2008
Release 1 Release 2
200920052004 2010
Page 17
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
TISPAN NGN Functional Entities
R e so u rc e a n d A d m issio n C o n tro l F u nc tio ns
R A C F
N etw o rk A c c e ssA tta c h m e n t F u n ctio n s
N A A F
O th er M ultim ed ia C o m p o n e n ts …
S trea m in g S e rv ic es
A p p lica t io n F u n c tio n s
C o re tra n sp o rt F u n c tio n s
A c c e ss T ra n sp o rt F u n c tio n s
N G N T e rm in a ls
C u sto m e rN e tw o rk s
U se rP ro file
F u n ctio n s
Other N
etworks
L e g a c yT e rm in a ls
G W
P S T N / IS D N E m u la tio n
IP M u ltim e d ia C o m p o n e n t
N N IT r a n sp o r t S tra tu m
S er v ic e S tra tu m
U N I
E d ge F u n c tio n s
A c c e ss F u n c tio ns
S e rv ic e an d
C o n tro l F u n c tio n s
C u s to m er a n d T e rm in a l F u n c tio n s
34
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overall TISPAN NGN Architecture
NGN as a modular system for independance of subsystems evolution• Transfer Functions• Network Attachment Subsystem (NASS)• Resource Admission and COntrol Subsystem (RACS)• PSTN / ISDN Emulation Subsystem (PES) • IP Multimedia Subsystem (IMS)• NGN Common Functions• Applications (out of scope)
Page 18
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
RACS in a Nushell
• QoS handling: checks resource availability and allocates resources• Has no service knowledge, only session knowledge• Provides admission control and gate control functionalities (including the
control of Media Gateways, Access Gateways, NATs and Firewalls)• Interface to transport layer
36
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
NASS in a Nutshell
• NASS Target: Hide access technology from control structure• Dynamic provision of IP addresses, authentication, authorization of network
access and access network configuration• Location information, location management and user privacy preferences
(e.g. for emergency services)
Page 19
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Architecture in the NGN settingO
ther IP Netw
orks
IP Transport (Access and Core)
T-MGF
I-BGF
AS
UPSF
P-CSCF
I/S-CSCF
BGCF
SLF
ChargingFunct ions
IWF
« Core IM S »
M w
M w /M k/M m
M r
M g
M j
M i
M p M nGm
Gq
ISCCx Dx
DhSh
Ic
Rf /Ro
Rf /RoIb
Ia
Id
PSTN/ISD
N
SGFMRFC MGCF
MRFP
Resource and Adm ission Con t rol Subsyst em
Network Attachment Subsystem
If
Ie
M wIBCF
M k
M k
UE
Ut
NetworkInterconnections
38
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
TISPAN PES - Functional Architecture
Other IP N
etworks
IP Transport (Access and Core)
T-MGF
I-BGF
UPSF
BGCF
ChargingFunct ions
IWFIMS-based PES
Mw
Mx
Mr
MgMj
Mi
Mp Mn
Gm
Gq'
ISC/MaCx Dx
DhSh
Ic
Rf/Ro
Rf/Ro
Ib
Iw
Gq'
PSTN/ISD
N
SGFMRFC MGCF
MRFP
Resource and Admission Control Subsystem
Ie
Mw IBCFMx
Mk
Other types of service logic
PSTN/ISDN Emulation logic
Application ServersRf/Ro
MG
ZZ
ZZ
AGCF
Gq'
P1Mw
P3
Ut
Ut
Network Attachment Subsystem
e2e2
MxP-CSCF
VGW
Ut
I/S-CSCF
SLF
Page 20
39
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
3GPP R6 and TISPAN R1 NGN: R6 comparison
• Network Attachment System– 3GPP: GPRS entities + HLR (PS part)– TISPAN: NASS entities
• Resource Admission Control– 3GPP: PDF and GGSN– TISPAN: RACS entities +
RCEF and BGF entities
• MM Session Control– 3GPP: IMS (R6)– TISPAN (R1) IMS (R6)
• TISPAN Documentation:– http://portal.etsi.org/docbox/tispan/Open/NGN-R1/Stable_Drafts/
40
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Q&A
Page 21
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
100%
1st ServicePOC
100%
Serv
ice
Infr
astr
uctu
re
2nd ServiceSe
rvic
eIn
fras
truc
ture
example
Vertical Solutions
SDP Infrastructure Economics
1st ServicePOC
60%
40%
• Horizontal solution can reuse infrastructure for more services to come• About 50% CAPEX Savings from 2nd service on• Carrier grade scalability of the infrastructure provided by “IMS”??
Serv
ice
Infr
astr
uctu
re
2nd Service
10%
40%
Serv
ice
Infr
astr
uctu
re
example
Horizontal Solution
Cost Savings
42
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
AAAServer
Evolution of Service Delivery Platforms
Web/ApplicationServer
IN / CAMEL Services
ApplicationServer
OSA / Parlay Interface
INAP/CAPInterface
OSA/Parlay/JAIN Gateway
IN Platform
StoredProgram Control
Services
Parlay X
PSTNGSMGPRS/UMTSVoIP
SIP App.Server
= Services
MultimediaServices
SIP
3rd PartyApplication
Services(Enterprises / Content)
Diameter
SIP Server
NGN / IMS
Page 22
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
NGN / IMS Idea: Try to get Control of IP Services
The IP network allows free communication between endpointsNGNB / IMS tries to control services on an IP networkIt is a trial to provide a better Internet!
A B
Server
IP
A B
Server
Controlby
IMS
44
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Architecture Principles
• Horizontal Architecture defining a dock for applications
• Defines service enabler capabilities• Build on existing IETF and telco SDP
standards• Provides compared to standard
internet• Better security, Service based QoS,
flexible charging and single sign onGGSNSGSN
ArchitectureArchitecture
Presence
Apps
GLMS
RAN
HSS IMS
• IMS does NOT standardise specific services, but enablers• BUT supports inherently multimedia over IP, VoIP, IM, presence (SIP)• IMS enables the flexibility in providing IP-based applications !!
Network
IMSand
Service Enablers
Applications
Page 23
45
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Infrastructure Functionality
GGSNSGSN
ArchitectureArchitecture
Presence
PoC
GLMS
RAN
HSS IMS
Network
IMSand
Enabling Services
Applications
• Implementing generic functionality in the infrastructure is mosteconomical !!
SIP Session-/Service Control Single-Sign-On User-AuthenticationSubscription Handling QoS/Media AuthorizationSignaling CompressionCharging Support and CorrelationRouting/Addressing Support Regulatory Service Support (e.g. LI) PresenceGroup List ManagementConferencing SupportPSTN Interworking SupportCS-Roaming Support… and more
46
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS enabling Control of GPRS / IP servicesIMS Core Idea: - Define an IP Multimedia Overlay-Network over GPRS (for Session control
based on Internet protocols!)- Data (Media) transport (as well as signaling transport) via GPRS- Provide control (QoS, security, Charging) for IP services and person-to-
person communication
Circuit Switched Net (GSM)
Packet Net (GPRS)
IP MultimediaSystem (IMS)Signalling (SIP)
Transport (RTP)
Note that IMS is for fixed networks applicable too
Page 24
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Motivation – Flexible Service ProvisionProvision of service enablers- Presence and Group server are considered key for the future- Example: Push to Talk, but more generally community services
Packet Net (GPRS)
IP MultimediaSystem (IMS)Signalling (SIP)
Transport (RTP)
Call / Session ServerPresence ServerMessaging Server
Application Server
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Q&A
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IMS
UTRAN
SGSN GGSNUE
PS Domain
IMS ArchitectureI-CSCF
Go Gi
I-CSCF
P-CSCF S-CSCFMw
HSS
Cx
Cx
Other IP/IMS networks
Mm
The PS domain provides the IP bearer to access to the IMS, i.e.
a PDP context.
The HSS holds the IMS service profile of the subscribers.
S-CSCF interconnects to externalIP networks and other IMS networks.If THIG is used by the operator to hide its internal configuration, the connection to external networks goes through an I-CSCF.
Gi
Traffic PlaneControl Plane
CSCFs are the IMS entities responsible of the call control: there are 3 types of CSCFs depending on their role:• P-CSCF (Proxy CSCF)• S-CSCF (Serving CSCF)• I-CSCF (Interrogating CSCF)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS
UTRAN
SGSN GGSNUE
PS Domain
IMS Architecture (cont.)I-CSCF
Go Gi
I-CSCF
P-CSCF S-CSCFMw
HSS
Cx
Cx
Other IP/IMS network
Mm
SGWMGCF
BGCF
IMS-MGW
Legacy/PSTN
Mk
Mi
Mg
Mj
MnGi
MRF
Gi
Mr
PDFGo
Gq Those entities are responsible for
interworking betweenIMS and CS
domain/PSTN
In Release 6, the PDF can be separated fromthe P-CSCF. Those twoentities are thenconnected through the Gq interface.
The MRF is usedfor multiparty call
control
Traffic PlaneControl Plane
AS AS are connected via ISC interface (extended
SIP) to S-CSF
ISC
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User Equipment (UE)
• Contains the SIP user agent• Establishes a GPRS PDP context for
– Signaling (either dedicated or a general one)– Media transport
• Contains ISIM for authentication– Public and private user id– User Network address– Security algorithms and keys– At least a USIM
• Correlate between session control and QoS reservation
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Call State Control Function (CSCF)
• Call State Control Function (CSCF)- Call set-up/termination and state/event management
- Address Analysis, translation, modification if required, addressportability, mapping of alias addresses
- provide service trigger mechanisms (service capabilities features) towards Application & services network (VHE/OSA)
- Interacts with HSS in the home domain to receive profile information for the user and
- Interact with MRF in order to support multi-party and other services
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Proxy Call Session Control Function (P-CSCF)
• First contact point for the UE (outbound proxy)– Forward registration to I-CSCF– Forward requests to S-CSCF (or I-CSCF)– Forward replies and incoming requests to UE
• Maintain security association with UE• Responsible for compression• Correlation between SIP and QoS• Enforce local policies• Possibly support routing to local service infrastructure
– Emergency call handling• Discovered through DHCP or during GPRS PDP establishment
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Interrogating CSCF (I-CSCF)
• Contact point within an operator– Discovered through DNS
• Assign S-CSCF to a user by contacting the HSS• May act as a THIG (Topology Hiding Inter-Network Gateway)
– Always on the path (RR and Service-Route) of any messageleaving the network
– Encrypt all entries added by the hiding network in outgoing messages
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Serving Call Session Control Function (S-CSCF)
• Acts as a registrar• Acts as a SIP proxy (forward messages ..)• Allocated to a user during registration• Always on the path of the user‘s SIP messages (use Service-Route
and RR)• Enforces service policies based on the user‘s subscription profile• Collects session information for billing• Interacts with application service platform• Acts as user agent when required (Notifications about de-
registrations and re-authentications, call termination)
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Home Subscription Server (HSS)
• Contains user profile information indicating– Private and public identities of the user– Authentication information– Which services and medias the user is eligible for using– Filtering criteria for choosing appropriate AS
• Assist I-CSCF in choosing the appropriate S-CSCF• Maintain subscription information about the user• Enforce provider policies• Connected through Cx interface to S-CSCF and I-CSCF (DIAMETER)• Connected also to AS
– Provide user service information• Allow multiple instances by using SLF (Subscription Location
Function)
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Application Server (AS)
• Services include third party CC, personalized routing ....
• Services are offered by home, visited or third party provider
• S-CSCF forwards requests to AS base (possible received from HSS)
• Results of AS sent back to S-CSCF• AS can act as UA, redirect or proxy• CAMEL and OSA optional
S-CSCF
AS
ISC
1
2 3
4
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Breakout Gateway Control Function (BGCF)
• Select PSTN/CS domain to forward call to– If the BGCF determines that the breakout is to occur in the same network
in which the BGCF is located within, then the BGCF shall select a MGCF which will be responsible for the interworking with the PSTN/CS Domain.
– If the break out is in another network, the BGCF will forward this session signalling to another BGCF in the selected network.
• How to choose an MGCF is not specified– Configuration– TRIP or similar
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Media Gateway Control Function (MGCF)
• Gateway to PSTN networks- Performs protocol conversion between the Legacy (e.g. ISUP,
R1/R2 etc.) and the IM domain call control protocols.
- Controls the parts of the call state that pertain to connection control for media channels in a MGW.
- MGCF selects the CSCF depending on the routing number for incoming calls from legacy networks.
– Establish bearer with appropriate code– Possibly translate codec– Act as UA (but no registration required)
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Media Gateway Function (MGW)
• Media Gateway Function (MGW)
– 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).
- Interacts with MGCF, MSC server and GMSC server for resource control.
- Owns and handles resources such as codecs, echo cancellers etc.
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Media Resource Function (MRF)
• Provide conferencing and announcement services
• Multimedia Resource Control Function (MRFC)– Interpret information from S-CSCF and AS
•Conference booking and floor control from AS for example
– Control MRPF• Multimedia Resource Processor Function (MRPF)
– Establish bearers based on MRFC requests– Media mixing and distribution– Media streaming for announcements
• Use H.248 (MEGACO) between the two components
MRFC
MRFP
SIP
H.248
Media
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IMS Application Layer Gateway (ALG)
• This component is defined for interworking between IPv4 and IPv6• The IMS ALG provides the necessary application function for the
SIP/SDP protocol stack in order to establish communication between IPv6 and IPv4 SIP applications.– The IMS ALG receives an incoming SIP message from CSCF nodes or
from an external IPv4 SIP network. – It then changes the appropriate SIP/SDP parameters, translating the IPv6
addresses to IPv4 addresses and vice versa. – The IMS ALG needs to modify the SIP message bodies and headers that
have IP address association indicated. – The IMS ALG will request NA(P)T-PT to provide the bindings data between
the different IP addresses (IPv6 to IPv4 and vice versa) upon session initiation, and will release the bindings at session release.
• Note: In contrast to NAPT, which are mapping IPv4/v6 applicationindependent, an ALG operates applications specific, here SIP/IMSspecific.
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IMS Border Control Concepts (Rel 7)• Based on operator preference, border control functions may be applied between
– two IM Core Network subsystem networks or – between an IM CN subsystem network and other SIP based multimedia network.
• These BC functions include:– Controlling transport plane functions;– Supporting functions to allow establishing communication between disparate
address realms' SIP applications;– Providing network configuration hiding to restrict the following information from
being passed outside of an operator's network: exact number of S-CSCFs, capabilities of S-CSCFs, or capacity of the network, etc;
– Screening SIP signalling information based on source/destination and operator policy (e.g. remove information that is of local significance to an operator);
– Generation of CDRs;– Selecting the appropriate signalling interconnect.
• In case border control concepts are to be applied in an IMS network, the IBCF acts as an entry point for this network (instead of the I-CSCF), and also acts as an exit point for this network.
– In this case the IBCF and I-CSCF may be co-located as a single physical node.
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SIP Signaling in IMS – The three SIP Servers
P-CSCF
I-CSCF
S-CSCF
REG REG REG
200 OK 200 OK 200 OK
Visited network Home network
P-CSCF - Proxy CSCF. The terminals point of contact to the IMS (in the visited network). Point where IMS interacts with bearer network for QoS.
I-CSCF - Interrogating-CSCF. Responsible for finding the right S-CSCF at registration. May also perform hiding of the S-CSCF network architecture.
S-CSCF - Serving-CSCF. Anker point for IMS subscribers. Performs authentication, registration and provides access for any application servers for that subscriber. Remains in all IMS signaling for that subscriber
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Principle of IMS as GPRS Overlay
S-CSCF I-CSCF
GGSNSGSN P-CSCFUTRAN
SIP signalling
User data
„Home“IMS Network
„Visited“Domain
Note: Depending on GPRS Roaming Architecture and GGSN Location„P-CSCF“ may be in Visited or Home Network
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IMS-Session: Home Networks are always involved
IP backbone
Access
Caller
Access
CalledValue added
services
Home
ISC
S-CSCF
Bearer Servicesoriented
WireLine
Bearer Servicesoriented
WLan
Home
ISC
S-CSCF
Bearer Servicesoriented
WireLine
TA?
WLan
FW?TA?GPRS
Value addedservices
UTRANFW?
TA?UTRANGPRS
Video/Audio/Signaling Video/Audio/Signaling
signaling signaling
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IMS: Separation of Signaling and Media transport
A’s visited networkUser A
User B
B’s visited network
A’s home network
B’s home network
Optional
Required onregistration,optional on
session establish
Required onregistration,optional on
session establish
GPRS
mobile to mobile session
P-CSCF
P-CSCF
I-CSCF
I-CSCFI-CSCF
I-CSCF
S-CSCF
S-CSCFValue added
services
Value addedservices
IMS
GPRS
IMS
GPRS
GGSN
GGSN
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IMS: Separation of Signaling and Media transport
A’s visited networkUser A
User B
B’s visited network
A’s home network
B’s home network
Optional
Required onregistration,optional on
session establish
Required onregistration,optional on
session establish
GPRS
mobile to mobile session
P-CSCF
P-CSCF
I-CSCF
I-CSCFI-CSCF
I-CSCF
S-CSCF
S-CSCFValue added
services
Value addedservices
SGSN
SGSN
IMS
IMS
GPRS
GGSN
GGSN
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IMS User Identity ConceptEach IMS User has at least one private and one or more public User Identities
• IMS Private User Identity:– belongs to the IMS operator– is not used for routing of SIP messages– uses the format defined in RFC 2486
• Example: user-X@ims.operator.com“– is stored on the ISIM card (in the mobile phone) and in the HSS (in the IMS User
Profile)
• IMS Public User Identity:– is public and may be subject to Number Portability– is used for routing of SIP messages– may use the SIP-URI format defined in RFC 3261 and/or the TEL-URI format defined
in RFC 2806• Example SIP-URI: “sip:user-X@company-X.com“• Example TEL-URI: “tel:+491231234567”
– At least one Public User Identity is stored on the ISIM card– All Public User Identities are stored in the HSS
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Relationship between Private d Public UID
• One Private UID may be mapped to several Public UIDs• One Public UID may be shared by several Private UID within (!) one
subscription
Private User Identity-1
Private User Identity-2
Public User Identity-1
Public User Identity-2
Public User Identity-3
Service Profile - 1
Service Profile - 2
IMS Subscription
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Public Service Identities (PSIs)
• Similar to public user identities, but allocated to services (ASs) ratherthan users
• Used to identify specific applications Servers (enablers), such as presence or group list servers
• Typically take the form of a SIP URI or TEL URI– sip: songdownload@t-online.de, presence@t-online.de, chat@partner.de– tel: +49-900-123-456
• PSIs are treated as PUIs, i.e. easy routing of SIP requests to ASs (as end user systems also called „service routing“
• Public Service Identities are not authenticated– i.e., there is no corresponding private user (service) identity
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How the IMS differs from RFC 3261 SIP Servers• The IMS was designed based on RFC 3261 (the CSCF is basically also a SIP Server)
… but includes much more!• Additional functions were added to the IMS:
– Subscriber Management, Service Control, Single-Sign-On User Authentication, – QoS/Media Authorization, Charging and Charging Correlation, – Resource Management, Interworking, Compression, Conferencing Support, Regulatory – Service Support, etc.
• Most of the IMS functions were taken from the IETF or were afterwards defined in theIETF:
– Update (RFC331), Preconditions (RFC3312), PRACK (RFC3262), Offer/Answer (RFC 3264), QoS/Media Authorization (RFC 3313), Event Notification (RFC 3265),
– Tel-URIs (RFC 2806), 3GPP P-Headers (RFC3455), Service-Route (RFC3608),– Asserted ID (RFC3325), DNS-Support (RFC 3263), SigComp (RFC3320, RFC3485, RFC 3486), – ENUM (RFC2916, RFC2915), SIP Refer (RFC3515), Digest AKA (RFC 3310), – Path-Header (RFC 3327), Security-Mechanism-Agreement (RFC3329), etc.
• A Service Infrastructure Network could also be built up starting with a standard RFC 3261 SIP Server.
• When extended to support the same Support Functions, then such a solution becomessimilar to the IMS.
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User Registration and Authentication
UE SGSN HLR GGSN CSCF‘s HSS IMS-AS
GPRS Attach
PDP Context Activation
IMS Registration and User Authentication
IMS Service Access
Bearer LevelAuthentication
IP Transport setup
IMSRegistration
IMSService Access
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UE Procedures for IMS Access
• Connect to the IP-CAN (IP Core Access Network) and acquire the necessary IP address, which includes, or is followed by, the P-CSCF discovery procedure
• Register to the IM subsystem as defined by the IMS registration procedures• If an UE explicitly deactivates the IP-CAN bearer that is being used for IMS
signalling, it shall first de-register from the IMS (while there is no IMS session in progress)
• If an UE explicitly deactivates the IP-CAN bearer that is being used for IMS signalling while an IMS session is in progress, the UE must first release the session and de-register from the IMS and then deactivate the IP-CAN bearers
• If an UE acquires a new IP address e.g. by changing the IP address according to, the UE shall re- register in the IMS by executing the IMS registration
• In order to be able to deliver an incoming IMS session, the IP-CAN bearer that is being used for IMS signalling need to remain active as long as the UE is registered in the IM CN subsystem
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Step 0: User RegistrationIMS Terminal P-CSCF I-CSCF HSS S-CSCF
(1) REGISTER(2) REGISTER
(3) Diameter UAR
(5) REGISTER
(4) Diameter UAA
(6) Diameter MAR
(7) Diameter MAA(8) 401 Unauthorized(9) 401 Unauthorized
(10) 401 Unauthorized
(11) REGISTER(12) REGISTER
(13) Diameter UAR
(15) REGISTER(14) Diameter UAA
(16) Diameter SAR
(17) Diameter SAA(18) 200 OK
(19) 200 OK(20) 200 OK
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Step 0: User RegistrationIMS Terminal P-CSCF I-CSCF HSS S-CSCF
(1) REGISTER(2) REGISTER
(3) Diameter UAR
(5) REGISTER
(4) Diameter UAA
(6) Diameter MAR(7) Diameter MAA
(8) 401 Unauthorized(9) 401 Unauthorized
(10) 401 Unauthorized
(11) REGISTER(12) REGISTER
(13) Diameter UAR
(15) REGISTER(14) Diameter UAA
(16) Diameter SAR
(17) Diameter SAA(18) 200 OK
(19) 200 OK(20) 200 OK
Request User information
to assign S-CSCF
S-CSCF selectionaccording to capabilities
HSS generates authentication
vectors
S-CSCF sends challenge
P-CSCF reads andremoves keys forsecure channel
with terminal
Calculatesresponse
to challenge
S-CSCFchecks answer
to challenge
Updates HSS
User-Profiledownloaded
Will further assert user’s identity as related to terminal
UE is registered
DNS query ofRequest-URI
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IMS Session Setup & Control
• This happens after User Registration (and Authentication!)• Why do we need the IMS Session Setup ?
1. Capability Negotiation (e.g. negotiation of session components, codecs, port numbers, addresses, etc.)
2. Network Resource Reservation and the support of QoS Preconditions• Additional Functions performed by the IMS during the IMS Session
Setup:– Routing to the Terminating IMS (= the IMS of the B-Party)– Routing / Breakout to the PSTN / CS-Domain when the B-Party is not in
the IMS, but in the PSTN / CS-Domain– Service Control / Invocation of Application Servers to trigger the
execution of Originating- and/or Terminating IMS Services– Integrity/Confidentiality Protection of SIP Messages– QoS/Media Authorization– SIP Signaling Compression
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IMS QoS Support
• The actual Network QoS for IMS services is provided by the Access Network (e.g. based on UMTS QoS) and the IMS network infrastructure(e.g. based on Diff-Serv support in routers and switches).
• The IMS provides a correlation and control mechanism based on the use of the Policy-Decision-Function (PDF).
• Key functions of the PDF:– acts as Policy Decision Point (PDP):
• the GGSN is the corresponding Policy Enforcement Point (PEP).– authorizes and controls the resource usage for each bearer (e.g. GPRS/UMTS
PDP-Context):• this prevents the misuse of Network QoS and the theft of service.• this allows to limit the resource consumption.
– exchanges Charging Correlation Identifiers with the GGSN (ICID, GPRS Charging ID):• this allows the correlation of charging information generated in the PS-
Domain (SGSN, GGSN) and in the IMS (e.g. CSCF, AS).
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006IMS Session Control – Complex Scenario
User A Registered
UE-A GGSN P-CSCF S-CSCF I-CSCF S-CSCF P-CSCF GGSN UE-B
User B Registered
INVITE
180 Ringing
200 OK
ACK
S
12
SS3
PRACKRR
RRB B
GoGo
200 OK
O Go
OGo200 OK
1 RR Resource Reservation
Service Control
Token generation
2 Resource Authorization 3 Same as 1,2
BO
Verify binding Open gate
Media Transport (RTP)
183 PR
200 OK
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Session Binding and QoS Bearer Control
• The Media/QoS Authorisation is performed on a per-session basisusing the Go-interface and an IMS Authorisation Token used for theIMS Session Binding.– enables the IMS to: authorise/open/close/modify the IMS Bearer Path (e.g.
for Voice/Video Traffic).• IMS Application Servers are not involved in the IMS Session Binding
Procedure.
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Session Initiation - 1
IMS Terminal #1 P-CSCF I-CSCF HSS S-CSCF(1) INVITE
(7) Diameter LIR
Originating VisitedNetwork
S-CSCF
Originating HomeNetwork
(3) INVITE
(5) INVITE
Evaluation of initial filter criteria
(2) 100 Trying(4) 100 Trying
(8) Diameter LIA
(6) 100 Trying
Terminating Home Network
P-CSCF IMS Terminal #2
Terminating VisitedNetwork
(9) INVITE
(11) INVITE
(10) 100 Trying
Evaluation of initial filter criteria
(12) 100 Trying(13) INVITE
(14) 100 TryingPre-alert user
(15) 183 Session Progress(16) 183 Session
Progress(17) 183 Session Progress(18) 183 Session
Progress(19) 183 Session Progress(20) 183 Session
Progress
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Session Initiation - 1
IMS Terminal #1 P-CSCF I-CSCF HSS S-CSCF(1) INVITE
(7) Diameter LIR
Originating VisitedNetwork
S-CSCF
Originating HomeNetwork
(3) INVITE
(5) INVITE
Evaluation of initial filter criteria
(2) 100 Trying(4) 100 Trying
(8) Diameter LIA
(6) 100 Trying
Terminating Home Network
P-CSCF IMS Terminal #2
Terminating VisitedNetwork
(9) INVITE
(11) INVITE
(10) 100 Trying
Evaluation of initial filter criteria
(12) 100 Trying(13) INVITE
(14) 100 TryingPre-alert user
(15) 183 Session Progress(16) 183 Session
Progress(17) 183 Session Progress(18) 183 Session
Progress(19) 183 Session Progress(20) 183 Session
Progress
Provisional responsesto avoid retransmissions
DNS query onRequest-URI
Locating S-CSCF where the called-party
is registered
AS Servicesfor caller
AS Servicesfor callee
Local registrar look-up for callee’s address
Callee is reachable, begin resource reservation
Authorize QoSresources (PDF)
Authorize QoSresources (PDF)
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Session Initiation - 2
IMS Terminal #1 P-CSCF I-CSCF HSS S-CSCF
Originating VisitedNetwork
S-CSCF
Originating HomeNetwork
(20) 183 Session Progress
Terminating Home Network
P-CSCF IMS Terminal #2
Terminating VisitedNetwork
Alert user
(39) 200 OK(40) 200 OK
(21) PRACK
Res
ourc
eR
eser
vatio
n
(22) PRACK
(23) PRACK
(24) PRACK(25) PRACK
(26) 200 OK
Resource
Reservation
(27) 200 OK(28) 200 OK
(29) 200 OK(30) 200 OK
(31) UPDATE(32) UPDATE
(33) UPDATE(34) UPDATE
(35) UPDATE
(36) 200 OK
(37) 200 OK(38) 200 OK
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Session Initiation - 2
IMS Terminal #1 P-CSCF I-CSCF HSS S-CSCF
Originating VisitedNetwork
S-CSCF
Originating HomeNetwork
(20) 183 Session Progress
Terminating Home Network
P-CSCF IMS Terminal #2
Terminating VisitedNetwork
Alert user
(39) 200 OK(40) 200 OK
(21) PRACK
Res
ourc
eR
eser
vatio
n
(22) PRACK
(23) PRACK
(24) PRACK(25) PRACK
(26) 200 OK
Resource
Reservation
(27) 200 OK(28) 200 OK
(29) 200 OK(30) 200 OK
(31) UPDATE(32) UPDATE
(33) UPDATE(34) UPDATE
(35) UPDATE
(36) 200 OK
(37) 200 OK(38) 200 OK
Authorize QoSresources (PDF)
PDP contextactivation
PDP contextactivation
QoS useenabled
QoS useenabled
Terminating LegOriginating Leg
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Session Initiation - 3
IMS Terminal #1 P-CSCF I-CSCF HSS S-CSCF
Originating VisitedNetwork
S-CSCF
Originating HomeNetwork Terminating Home Network
P-CSCF IMS Terminal #2
Terminating VisitedNetwork
(47) PRACK(48) PRACK
(49) PRACK(50) PRACK
(51) PRACK(52) 200 OK
(53) 200 OK(54) 200 OK
(55) 200 OK(56) 200 OK
Alert user(41) 180 Ringing
(42) 180 Ringing(43) 180 Ringing
(44) 180 Ringing(45) 180 Ringing
(46) 180 Ringing
Acceptsession
(58) 200 OK(57) 200 OK
(59) 200 OK
(61) 200 OK(62) 200 OK
(60) 200 OK
(63) ACK(64) ACK
(65) ACK(66) ACK
(67) ACK
Media Transport (RTP)
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Session Initiation - 3
IMS Terminal #1 P-CSCF I-CSCF HSS S-CSCF
Originating VisitedNetwork
S-CSCF
Originating HomeNetwork Terminating Home Network
P-CSCF IMS Terminal #2
Terminating VisitedNetwork
(47) PRACK(48) PRACK
(49) PRACK(50) PRACK
(51) PRACK(52) 200 OK
(53) 200 OK(54) 200 OK
(55) 200 OK(56) 200 OK
Alert user(41) 180 Ringing
(42) 180 Ringing(43) 180 Ringing
(44) 180 Ringing(45) 180 Ringing
(46) 180 Ringing
Acceptsession
(58) 200 OK(57) 200 OK
(59) 200 OK
(61) 200 OK(62) 200 OK
(60) 200 OK
(63) ACK(64) ACK
(65) ACK(66) ACK
(67) ACK
Phone startsringing
Aknoledgesphone ring
Answer the call
Starts media flow
Starts media flow
Media Transport (RTP)
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IMS Online / Offline Carging
• The IMS architecture supports both online and offline chargingcapabilities.
• Online charging– is a charging process where IMS entities, such as an application server
(AS), interact with the online charging system.– the online charging system in turn interacts in real time with the user's
account and controls or monitors the charges related to service usage.• Offline charging
– is a charging process where charging information is mainly collected afterthe session and the charging system does not affect in real time theservice being used
– a user typically receives a bill on a monthly basis, which shows thechargeable items during a particular period.
• Due to the different nature of charging models different architecturesolutions are required.
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IMS Charging Architectures
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Offline Accounting Principles
• Charging Trigger Function (CTF)– watches for accountable events– sends them
• Charging Data Function (CDF)– construct CDRs from events
received via Rf reference point– events may be of several types
• Charging Gateway Function (CGF)– collect, validate and (persistantly)
store CDRs (in files)– forward batch files to Billing
domain
CN Domain
Service element
Sub- system
Billing Domai
Rf Ga Bx
C
T
F
C
D
F
C
G
F
3GPP network
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Rel. 6 – IMS Offline Charging Architecture
• Focus is IMS related (bearertraffic excluded for IMS spec.)
• Compared to Rel. 5– CCF splitted into CDF and
CGF – Ga added
• First rules on what events to trigger Rf commands arespecified for– P/I/S –CSCF– BGCF– SIP AS– MGCF– MRFC
Billing Domain Billing Domain
BGCFBGCF
MGCF MGCF
MRFC MRFC
SIP ASSIP AS
CDF CDF
CGF CGF
P - CSCF S - CSCF P - CSCF I - CSCF
S - CSCF
Rf Ga
Bi
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Offline Charging Example
Offline Charging is basedon the Diameter messages
- Account Request (ACR)- Account Answer (ASR)
Start: open a new CDRInterim: adds further infoStop: closes the CDREvent: unreleted session
CDR
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Online Accounting Principles• Charging Trigger Function
– Sends events for authorization to OCF– Must delay resource usage until permission is
granted– Must support quota supervision during resource
usage/consumption
• Online Charging Function has 2 modules– Session based Charging
• charges network / user sessions (e.g. voice calls, GPRS PDP contexts or IMS sessions)
– Event based Charging• event-based online charging (also referred
to as “content charging”) in conjunction with any application server (e.g. SIP) or service NE
• Account Balance Management Function• Rating function (for data volume, session
time & service events)
CN Domain
Service element
Sub- system
Ro
C
T
F
3GPP network
CAP
O
C
F
ABMF
RF
OCS
Rc
Re
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Rel. 6 – IMS Online Charging Architecture
Billing Domain Billing Domain
BGCFBGCF
MGCFMGCF
MRFCMRFC
SIP ASSIP AS
OCS OCS
P -CSCFS -CSCFP -CSCFI -CSCF
S -CSCF IMS - GWF
Ro
ISC
• Specification for IMS (no bearer included)
• IMS Gateway Functionas new element– either part of OCS or– Stand-alone solution
(e.g. SIP AS) • Triggering behaviour
not specified
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Online Charging Example
Online Charging is basedon the Diameter messages
- Credit Control Request(CCR)
- Credit Control Answer(CSR)
The IMS-GWF requests unitsfrom the Online CharingServer (OCS) to provide a service (e.g. a session or a subsription, or any otherservice)
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IMS Diameter Base Protocol Extensions
Base
Pro
toco
lE
xten
sion
s
Rf application defined in 3GPP TS32.299 uses the accounting portion of the base protocol and its server is stateless.Ro application defined in 3GPP TS32.299 extends Diameter Credit Control Application (DCCA) RFC4006, which uses both stateful and stateless part of auth-portion in the base protocol.
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IMS Security
• Two security solutions are proposed• Full IMS security
– Standardized in Release 5 and 6 with full features– Defines security in the network and the terminals– Requires ISIM and rich features in the terminal, P-CSCF and S-CSCF
• Early IMS Security– Standardised in Release 6– Idea: Reuse GPRS authentication (and IP address) for IMS authentication– Developed for early IMS deployment without existance of all security
enablers– Not stringend as the full IMS security solution– Intended to have minimal impact on existing terminals– Offers less security but good enough for early deployment
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Complete IMS Security Solution
• Divided into:– Network Domain Security (already existing for GPRS)– Access Domain Security (linked to SIP and CSCFs / HSS)
• SIP Security is provided on a hop-by-hop fashion– End-to-end security is not supported !
• Terminals accept a UICC (Universal Intergraded Circuit Card) that contains an ISIM (IMS Subscriber Identity Module) application
• The ISIM stores identities (public, private), home domain, and long term security keys
• The S-CSCF authenticates the user at SIP registration time• The security mechanism is negotiated (but only IPSec is supported so far)• Authentication scheme based on the UMTS AKA (Authentication and
Key Agreement) called IMS AKA• Delegate identity enforcement to the P-CSCF• P-CSCF and UE establish an IPSec connection for integrity protection
(Release 5 onwards) and confidentiality (Release 6 onwards)
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Complete IMS Security
GPRS DomainExisting GPRS Access
Security
SIP UAIMS Visited
IMS Home
Security Mechanism Agreement
Authentication & Key Agreement (AKA)
Network Domain Security
Integrity Protection
IMS
Secu
rity
SecureApps
SecureApps
Non-secureApps
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Early IMS Security
• There is no IPsec connection (UE – P-CSCF), no IMS AKA, and no HTTP Digest authenication
• Idea: Reuse / rely on GPRS authentication• Binding between public/private user identity and GPRS allocated IP address is
created in the HSS• The GGSN authenticates the GPRS usage based on the IMSI• The GGSN uses RADIUS to send the HSS the attached user´s IP address, IMSI
and MS-ISDN• The HSS binds the IMSI and MS-ISDN to the private and public user identities• The P-CSCF verifies that the source IP address in the IMS signalling IP
packets is the same as the „send by“ parameter in the Via header field of SIP REGISTER request
– If they differ, the P-CSCF adds a „received“ parameter to the record the seen IP address
• When the S-CSCF requires to authenticate the user, it checks ist IP address in the „received“ or „sent by“ parameters of the register request
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Early IMS Security
IMS Terminal GGSN I-CSCF HSS S-CSCF(1) PDP Context
Activation Request
P-CSCF
(3) RADIUS ACA
(2) RADIUS ACR
[IP address, IMSI, MSISDN]
(18) 200 OK
(7) REGISTER “sent-by“ IP address
(4) PDP Context ActivationAccept IP address
(5) REGISTER “sent-by“ IP address
(6) GGSN prevents IP spoofing
(8) Check Source IP address against “sent-by” parameter
(9) REGISTER “sent-by“ IP address “received“ IP address (10) Diameter UAR
(11) Diameter UAA(12) REGISTER
(13) Diameter MAR
(14) Diameter MAA[IP address]
(15) Check received IP address against “sent-by” or
“received” IP address
(16) Diameter SAR
(17) Diameter SAA(19) 200 OK(20) 200 OK
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Media Plane Security
• IMS User plane security relies on bearer network security (e.g. UMTS/GPRS packet domain ciphering in Release 5)
• There is no end to end security for media flows• Opportunities in future releases to integrate end to end key agreement
with SIP• End to end encryption options
– Application layer (e.g. S-RTP)– Network layer (e.g. IPsec)
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Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Q&A
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SIP enables different AS Modes of Operation
Four modes of operation are distinguished:• Application Server acting as terminating UA, or redirect server• Application Server acting as originating UA• Application Server acting as a SIP proxy• Application Server performing third party call control/ B2BUA mode
CSCF
AS(Content Server)
CSCF
AS(Wake up Svr)
CSCF
AS(Call Forw.)
CSCF
AS(Click2Dial)
RTPSIP
A BA B A B
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How does a SIP AS Provide Enhanced Services
• S-CSCF determines that a call requires enhanced service processing– Filtering may be based on calling / called party or other mechanism
(defined by filtering criteria) eg. SIP message type, header fields, etc.• Based on filtering criteria, the S-CSCF determines the address of the
Application server and relays the call to the AS function. The Application Server receives the call and invokes the appropriateservice logic taking one of the following actions:– Redirects the call to a new destination– Send the call back through the S-CSCF in order to monitor subsequent call
events (ie act as a SIP Proxy)• The Application Server (based on some other input) can also set-up
calls between other entities in the network (ie. act as a B2BUA)
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Major Service Platform Interfaces
Service Delivery Platform (Application Server)
Service Platform Trigger PointsService Platform Adaptor
SIP B2BUA Interface
HSS
S-CSCF
SPT
SP Filter criteria 2 SPT Mapping
ISC = Ext. Session Initiation Protocol
SIPSIPSIP Proxy Server
Sh = Diameter
Cx = Diameter
Note: Cloning of IN principles!
Value Added Services
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Major Service Platform Interfaces
Service Delivery Platform (Application Server)
Service Platform Trigger PointsService Platform Adaptor
SIP B2BUA Interface
HSS
S-CSCF
SPT
SP Filter criteria 2 SPT Mapping
ISC = Ext. Session Initiation Protocol
SIPSIPSIP Proxy Server
Sh = Diameter
Cx = Diameter
Note: Cloning of IN principles!
Value Added Services
Application Data(Filter Information)User status changes
User AuthenticationUser locationUser Profile (Filter Information)
Applicationspecific servicecontrol
Detection Points:Methods / Responses,Headers, SDP info, etc
DP Criteria:AS-Specific Methods / Responses,Headers, SDP info, etc set by AS/HSS
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IMS Diameter Base Protocol Extensions
Base
Pro
toco
lE
xten
sion
s
Cx application defined in 3GPP TS29.229, Sh application defined in 3GPP TS29.329 use the stateless part of the auth-portion in the base protocol.Rf application defined in 3GPP TS32.299 uses the accounting portion of the base protocol and its server is stateless.Ro application defined in 3GPP TS32.299 extends Diameter Credit Control Application (DCCA) RFC4006, which uses both stateful and stateless part of auth-portion in the base protocol.
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Cx (and Dx) Interface
• Cx - Interface supports information transfer between S-CSCF and HSS– Diameter application for user profile handling & user authentication
• to exchange location information● to authorize a user to access the IMS• to exchange authentication information• to download and handle changes in the user data stored in the server
• Dx – Interface between I-CSCF and the Subscription Locator Function (SLF) –in case of HSS look-up
– Diameter redirect agent functionality to retrieve an HSS address
• Both RPs are pecified in 3GPP TS 29.228 and TS.29.229 – TS 29.228 IM Cx and Dx interfaces; Signalling flows and message contents– TS 29.229 IM Cx and Dx interfaces based on the Diameter protocol; Protocol details– (http://www.3gpp.org/ftp/Specs/archive/2x_series/2x.xxx)
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IMS Cx Diameter Extensions
Cx Application (Described in 3GPP TS29.228, 3GPP TS29.229)Defined between I-CSCF and HSS, between S-CSCF and HSS.Uses stateless part of the auth-portion in the base protocol.Defines new commands:
Defines a series of vendor specific AVPs.
Push-Profile-Request / Push-Profile-Answer
Registration-Termination-Request / Registration-Termination-Answer
Multimedia-Auth-Request / Multimedia-Auth-Answer
Server-Assignment-Request / Server-Assignment-AnswerLocation-Info-Request / Location-Info-AnswerUser-Authorization-Request / User-Authorization-Answer
Command-Name
PPR/PPA
RTR/RTAMAR/MAA
SAR/SAALIR/LIAUAR/UAAAbbreviation
S-CSCF, HSS
S-CSCF, HSSS-CSCF, HSS
S-CSCF, HSSI-CSCF, HSSI-CSCF, HSS
Between
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Sh Interface
• Interface between HSS and Application Server (AS)• Diameter application that allows a Diameter server and a Diameter
client:• to download and update transparent and non-transparent user data• to request and send notifications on changes on user data
• Further information on the Sh reference point is provided in – TS 29.328 IM Sh interface; Signalling flows and message contents– TS 29.329 IM Sh interface based on the Diameter protocol; Protocol details
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IMS Sh Diameter Extensions
Push-Notification-Request / Push-Notification-AnswerSubscribe-Notifications-Request / Subscribe-Notifications-AnswerProfile-Update-Request / Profile-Update-Answer
User-Data-Request / User-Data-AnswerCommand-Name
PNR/PNASNR/SNAPUR/PUAUDR/UDA
Abbreviation
Sh Application (Described in 3GPP TS29.328, 3GPP TS29.329)Defined between AS and HSSUses stateless part of the auth-portion in the base protocol.Defines new commands
Defines a series of vendor specific AVPs.
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IMS User Profile
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IMS Initial Filter Criteria• The IFC is the key point for service provisioning in IMS and specified in 3GPP TS 23.218 and 29.228 • The S-CSCF downloads the IFC‘s for a particular user from HSS and has the ability to forward SIP
messages to an appropriate Application Server (SIP AS, OSA SCS)• AS application/service invocation is triggered as a result of a pattern matching on any SIP header
or body
HSS
IM User Profile(s)S-CSCF
IM User Profilesstorage
AS1
Application
ApplicationAS2
Application
ApplicationAS3
Application
Application
1 INVITE
2 INVITE 3 INVITE 4 INVITE 5 INVITE
6 INVITE
Cx - User Profile download/update
Filter Criteria 2 SPT ProcessingPrio 1 = AS1, Prio 2 = AS2, Prio 3 = AS 3, etc.
iFc 1 met iFc 3 met
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Service Example (1) —Single AS case
Example 1: Single application server triggering
3. P
UB
LIS
H
4. 2
00 O
K
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Service Examples (2) — Multiple AS case
Example 2: Multiple application servers triggering
3. MESSAG
E4. M
ESSAGE
2. Filter Evaluation
6. M
ESSA
GE
7. M
ESSA
GE
5. Filter Evaluation
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Scalability of the IMS
HSS
S-CSCF 1
SIP AS X
Sh
Cx
ISC
S-CSCF 2 S-CSCF Y
SIP AS 2SIP AS 1
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Different AS Alternatives
• CAMEL Services via Camel Support Environment (CSE): – intended for the support of existing IN Services (provides service continuation).
• OSA Services via Open Service Access Service Capability Server: – intended for the support of 3rd Party Application Providers. OSA SCS provides
access and resource control.
• IMS services on SIP-Application Server:– intended for new services. A multitude of widely known APIs (CGI, CPL, SIP
Servlets) is available.
• IMS services directly on the CSCF (similar to SIP AS):– SIP-AS co-located on the CSCF– seems to be useful for simple services. May be beneficial for the Service
Availability and the Service Performance.
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SIP ASHSS(AAA)
Media Server
SIP
IMS Application Server Options
DiameterSIP
OSAGTW IM-SSF
App
licat
ion
Serv
erIM
S C
ore
Serv
er
P/I/S-CSCF(SIP Proxy)
SIP ServerPDF
OSAAS CAMEL
ApplicationServers
Local AS
RTP
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INSCP
Online &OfflineCharging (ECF, CCF)
CAMEL Reuse within IMS
CAMEL Support Env.(Application Server)
IN App 1
Service Platform Trigger PointsIM SSF (SIP2CAP)
SIP Interface
ShHSS
S-CSCF
SPT
SP
Filter criteria
ISC
SIP
SIP-Server
Sh = Diameter
Cx = Diameter
Ro + Rf = Diameter
Diameter
CAP
CAP Interface
SIP 2 CAP mapping needed!
IM SSF
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3GPP CAMEL
• CAMEL = Customized Applications for Mobile Enhanced Logic• CAMEL
– Is the use of IN in mobile circuit switched and packet switched networks: GSM/GPRS
– IN-based architecture enabling to offer operator specific services (OSS) to mobile subscribers even when roaming in another network (international roaming)
• CAMEL enables inter-network GSM/GPRS service control, by reusingthe existing international signaling transport infrastructure– CAMEL Application Protocol (CAP) is based on IN Capability Sets 1 and 2– CAMEL additionally exploits Mobile Application Part (MAP)
• CAMEL Standardisation started in 1994 (as a GSM Phase 2+ Feature)• CAMEL evolves in Phases, which are part of Releases!!!
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CAMEL Phases
• Camel Phase 1– Basic Call Control functionalities for GSM calls
• Camel Phase 2– ApplyCharging in VPLMN : GSM calls are monitored directly in VPLMN– Announcement : access to annoucements directly from the VPLMN
• Camel Phase 3– Handling of GPRS Sessions and pdp-contexts for session control, monitoring
(location update, QoS,…) and charging (time and volume triggers)– Support of SMS-MO through CS and PS networks– Anytime interrogation and modification of customer data in HLR– Mobility management enhancements
• Camel Phase 4– Multi-leg GSM call handling– Creation of a new GSM call– PLUS: Interworking with IP Multimedia Subsystem
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CAMEL(SCF)
S-CSCF
IM-SSF
HSS
MSC (SSF)
HLR
2G Circuit Switch Voice Network
3G IP based Voice & Data Networks
SGSN (SSF)
2.5G Packet Switch GPRS Data Network
MAP
Home Network
CAP(over IP)
CAP
MAP
SIP
CAMEL Evolution
Camel Phase 1 + 2Camel Phase 4
Camel Phase 3
IVR (IP)
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Home Network
CAMEL Phase 4 in IMS Domain
Visited Network
IP Multimedia
InterrogatingNetwork
CSE HSSMAP
imSSF
Cx
IP Multimedia
IP Multimedia Subsystem
GGSN
MGCFT-SGW
MGWPSTNPLMN
SIP SIP
proxyCSCF
SIPS-CSCF
CAP over
IP
SGSN
• IM-SSF provides– Triggering of CAMEL services in gsmSCF– Call State model (O-IM-BCSM / T-IM-BCSM) based on CAMEL Phase 3!
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MOC VoIP with CAMEL interaction
S-CSCF/imSSF HSSUE CSE
Visited network Home network
Invite
If calling subsc. is not registered, dialogue with HSS is opened to obtain O-CSI
InitialDPCAP instructionsAnalysis for calls
requiring IN i.e. trigger criteria in O-CSI
P-CSCF
A
I-CSCF
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Parlay AS (API)
Online &OfflineCharging (ECF, CCF)
OSA / Parlay AS within IMSService Delivery Platform
(Application Server)Parlay App 1
FW
SIP Interface
ShHSS
S-CSCF
SPT
SP
Filter criteria
ISC
SIP
SIP-Server
Sh = Diameter
Cx = Diameter
Ro + Rf = Diameter
Diameter
Parlay X GWParlay App 2
Parlay X AppParlay X App
Parlay GTW
MPCC MMM PRES CHARG
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Parlay/OSA (Open Service Access) define an API that enables operatorand 3rd party applications to make use of network functionalitythrough a set of open, standardised service interfaces
Parlay/OSA API
Gateway
Mapping to network specific protocols
App 1 App 2 App N Applications (independent of underlyingnetwork technology)
3GPPETSIParlayJAIN SPA
OSA/Parlay/JAIN: One Set of Open APIs
ISDN GSM/GPRS Internet / UMTS
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OSA / Parlay’s Technical Approach
• Framework Interface Set - Common Functions That Are Required to Enable Services to Work Together in a Coherent Fashion e.g.
– Authentication, Discovery, Manageability• Transport interface
– CORBA, WSDL (Web Services)• Service Interface Set(s) - Common Functions
That Deliver Whole Complex Services or Sub-components of Services e.g
– Call Control, User Interaction, Content-based Charging, Location, Presence and Availability, Messaging, Policy Management, Quality of Service …
• Resource Interfaces - Interfaces used between a Parlay Gateway and network elements
– not specified in Parlay (but hints in OSA)
ApplicationServer
Frameworkinterface
Parlay/OSA GatewayResourceinterface
Resourceinterface
Serviceinterface Th
e Par
lay/O
SA A
PI
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Focal Points of API Standardisation (Parlay 5)
UserInteraction
Data sessioncontrol
GenericMessaging
ConnectivityManagement
AccountManagement
Contentbased charging
TerminalCapabilities
PolicyManagement
Presence &Availability
Management
Call Control
Mobility
Framework
Not
par
tof O
SA
MMMessaging
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Parlay – OSA – ETSI – JAIN Relationhip
ES 201 915-14TS 29.1980-14PAMES 201 915-13TS 29.1980-13Policy ManagementES 201 915-12TS 29.1980-12ChargingES 201 915-11TS 29.1980-11Account ManagementES 201 915-10N/AConnectivity ManagementES 201 915-9N/AMessagingES 201 915-8TS 29.1980-8Data Session ControlES 201 915-7TS 29.1980-7Terminal CapabilitiesES 201 915-6TS 29.1980-6MobilityES 201 915-5TS 29.1980-5User InteractionES 201 915-4TS 29.1980-4Call Control
ES 201 915-3TS 29.1980-3FrameworkES 201 915-2TS 29.1980-2Common TypesES 201 915-1TS 29.1980-1Overview
ETSI OSA API Version 1 spec.
3GPP OSA API Release 4
spec.
Parlay Version 3.1 spec.
JSR-123 v.1.0 (PAM)
JSR-098 v.1.0 (ULS)JSR-103 v.1.0 (UI)
JSR-021 v.1.1 (JCC)
JSR-024 v.1.0 (TSM, SD, SAM)JSR-119 v.1.0 (IM)
JSR-145 v.1.0 (Common)JSR-136 v.1.0 (JTSP)
JAIN SPA API spec.
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OSA/Parlay Interfaces – Classic vs. Parlay X
Parlay X App
SIPServer SCP/CSE
XMLScript Java VB
Parlay X Gateway
“MakeACall (A,B)” “GetCallInfo”
HLR
XML Transport: Simple XML sequences
over SOAP, CORBA, HTTP, …Parlay X APIs
“Web Services” AppParlay
C++/ Java App
ClassicParlayAPIs
Parlay Gateway
XMLScript Java VB
XMLCORBAIDL, Java
CORBAIDL, Java,XML, …
createCall()routeReq(A)routeReq(B)…
XML Transport: Complex XML sequences
over SOAP, CORBA, HTTP, …
routeRes(A)routeRes(B)…
IIOP
createCall()routeReq(A)routeReq(B)…
routeRes(A)routeRes(B)…
Not reallyDemanded!
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NetworkResource
NetworkResource
NetworkResource
NetworkResource
Example Parlay X Web Services
Send SMS
Initiate Call Conference
ZipCodes
Whoseon-line ?
Sort inorder
Currentlocal
Weather
Airline flightcheckMake
payment
AccountStatement
NewApplication
Note: Network Operator acting as Web Service Provider
Directory
LatestScores
PublicUDDI
Registry
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3GPP Parlay X Web Services
• Parlay X Web services havebeen adopted by 3GPP CN TSG (September 2004) for inclusionin OSA Release 6
– The documents are numbered TS 29.199-xx-600
– 3GPP TS 29.199 is structured in 14 Parts
Part 14: PresencePart 13: Address List ManagementPart 12: Multimedia ConferencePart 11: Audio callPart 10: Call handlingPart 9: Terminal locationPart 8: User statusPart 7: Account managementPart 6: PaymentPart 5: Multimedia Message Service (MMS)Part 4: Short Message Service (SMS)Part 3: Network-initiated third party callPart 2: Third party call Part 1: Common
TS 29.199 specifications
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The JAIN APIs
JAIN Service Logic Execution Environment (JSLEE)
JAIN Call Control (JCC) and JAIN Coordination and Transactions (JCAT)
JAIN ServiceCreation
Environment(JSCE)
Secure Telco Space
TCAP ISUP INAP SIP MAP MGCP
Untrustedthird-party
applications
JAIN Service Provider Access (JSPA)
Trusted third-party
applications
VendorIndependence
ProtocolIndependence
NetworkIndependence
OperatorIndependenceSecurity Interface
PSTNBroadbandIP SatelliteWireless
Open API
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Online &OfflineCharging (ECF, CCF)
SIP Application Server (Servlets)
Service Platform Trigger PointsSIP Servlet Engine
SIP Interface
ShHSS
S-CSCF
SPT
SP
Filter criteria
ISC
SIP
SIP-Server
Sh = Diameter
Cx = Diameter
Ro + Rf = Diameter
Diameter
SIP Service ServletsSIP Service Servlets
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SIP Servlet API
• Objectives of the SIP Servlet API as specified in the JSR116 – SIP Servlet API Version 1.0
– SIP signalling – Allows applications to perform a reasonable complete set of SIPsignalling actions, including support for acting as user agent client (UAC), user agent servers (UAS), and proxy.
– Simplicity – Containers handle “non-essential” complexity such as managing network listen points, retransmissions, CSeq, Call-ID, Via headers, routes etc.
– Converged applications – It is possible for containers to support converged applications which make use of multiple protocols such as HTTP and SIP. Typical applications are web, telephony and presence.
– Third party application development – The servlet model supports third party application development. An XML deployment descriptor is used to communicate application configuration.
– Application composition – It is possible for several applications to execute on the same incoming or outgoing request or response. Each application has its own set of rules and execute independently of other applications in a well-defined and orderly manner.
– Carrier grade – Servlets store application data in container managed sessionobjects. Implementations may persist and/or replicate this data to achieve high availability.
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SIP Servlets
(taken from ‘SIP Sevlets White paper’ by Jose Soler Lucas)
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SIP Servlets
#1 INVITE TM
#2 pass invitationto call processinglogic
#3 return anaction
#4a INVITE TM@cell
#4b INVITE voicemail@trash
SIP ServletContainer
Ser
vlet
SIP Servlet API
Ser
vlet
Call Screening Service
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Servlet Control SIP.XML
• SIP.XML is xml-code that specifies the Servlet container habit and controls the Servlet invocation.
• An Eclipse Plugin enables the graphical control / modification of the SIP.XML within the SIP Servlet Execution Environment.
Servlet ContainerSIP.XML
Servlet orarchive
Servlet orarchive
Servlet orarchive
Servlet orarchive
SIP Request
Match of Criteria
Note: The SIP XMLEnables to host multipleand independent Servlets(Applications) within on one SIP AS !
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Converged SIP and HTTP Sessions
• In Converged Applications, SIP Servlet and HTTP Servlet share the same Servlet Context through Converged Application Helper.
• Through Listener and attributes in Context, HTTP and SIP Servlet can communication with each other.
• More than one HTTP Sessions and SIP Sessions belong to the same SipApplicationSession, which acts as bridge between HTTP and SIP world.
140
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
SIP AS vs. CAMEL vs. OSA/Parlay
• CAMEL supports:– legacy IN services in 2G and 3G networks– Services based on proven and reliable IN technology (reuse!)– But CAMEL is expensive and limited in evolution
• SIP AS supports:– Multimedia conferencing services, integrated with HTTP– Exploitation of cheaper internet technology– Easier service creation, but not yet proven for carrier grade services
• OSA is an API (!!) which could be mapped to boh CAMEL and SIP– OSA is enabling EAI in Telecoms– Proven technology (reuse of existing services in NGN)– Support implementation of different business model (walled vs. open
garden)– Best support of 3rd parties
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Relating OSA/Parlay vs. CAMEL vs. SIP AS
OSA/Parlay FMC Services (Apps Servers)
Seamless NGN Services (opt. by 3rd Parties)
OSA Gateway
MSC
Camel CSE
CAP
ReuseCAMEL Services
GGSNSGSN
CAP GSM /GPRS
Parlay (X) API
OSA Gateway
SIP AS
S-CSCF
Build newMM Services HSS
(AAA)
3GPP IMS
SIP CAP
WLAN / DSL WAG
PDFPDF
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• IMS Motivation• IMS Overview• IMS Key protocols (IETF SIP and Diameter) • IMS Key components• IMS Application Server options• Sample IMS Multimedia Applications• The IMS Playground @ FOKUS• Summary• Q&A and IMS Playground Demos• References & Acronyms
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IMS Applications
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS integrates different Communication Services
Voice
SMS
Instant Messaging
MMS
Pre-IMS Communication(“Service Islands”)
IMS Communication(“Combinational Services”)
Voice / VideoSMS
Instant Messaging
MMS
From the usage of specificindividual communication services ... ... to the integrated usage of different
communication services centeredaround presence information and
within groups ( communities)
GroupsPresencePoC
TV
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS for VoIP Supplementary Services• Example IMS Service Architecture for an IMS Voice/Video/Data telephony service:
– the SIP-AS provides Supplementary Services such as e.g. Call-Forwarding, Call-Barring, Simultaneous-Ringing, etc.
ApplicationsApp
licat
ions
146
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Multimedia Call – Change of Media Scenario
• Change of Media Scenario uses basic IMS components, requests enhanced functionalities on client side (e.g. Video) and Operator dependent change of PDP-context.
• Change of Media Scenario is a seamless switch of media –No session interruption
Alice (caller) Bob (callee)
(2) INVITE (SDP=Voice)(3) 200 OK
(1) INVITE (SDP=Voice)
(4) 200 OK
P-/I-/S-CSCF
IMS
environment
Do you wantto see mynew skirt?
(7) 200 OK(5) INVITE (SDP=Voice+Video)
(8) 200 OK
(6) INVITE (SDP=Voice+Video)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Multimedia Call – Rich Converged Call Scenario
• A Rich Converged Call Scenario makes use of the advantages of the peer to peer protocol SIP and the well known client-server protocol HTTP. It enables a client or an application to perform a HTTP Push with the target to provide another subscriber with personalized web content.
• A Rich Converged Call Scenario requests minor but specification compliant modification of the SIP User Agent to open the website automatically.
Alice (caller) Bob (callee)
(2) INVITE (SDP=Voice)(3) 200 OK
(1) INVITE (SDP=Voice)
(4) 200 OK
P-/I-/S-CSCF
IMS
environment
I found an excellentweb/ wap site. I will push it to you.
(7) 200 OK(5) INFO (body=http://open-ims.org)
(8) 200 OK
(6) INFO (body=http://open-ims.org)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Instant Messaging
• Near real-time exchange of multimedia messages in a one-to-one or one-to-many connection
• Instant Messaging is the first presence-enabled application in the mobile environment
• Different forms of IM– immediate messaging– session-based messaging– deferred delivery messaging
• Different types of IM– Text– Audio– Picture– Video
• IMS insures the interworking between different message types
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Immediate messaging
• User A generates a Message consisting of text or multimedia content and fills the request-URI with the address of the recipient B
• The IMS infrastructure (P/I/S-CSCF) forwards the message to the recipient
• Once user B receives the message, he replies with a 200 OK message
• Note: Each immediate message is an independent transaction and is not related to any previous requests
MESSAGE MESSAGE MESSAGE
200 OK200 OK200 OK
User A User B
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Session-based messaging
• Before user A sends a MESSAGE, he invites user B to a message session by generating an INVITE message
• Once the session has been established, user A and B can exchange messages• Note : A session has a well-defined lifetime: a message session starts when
the participants begin the session and stops when the participants close the session
MSRP Send MSRP Send MSRP Send
MSRP 200 OK
User A User B
INVITE
200 OK
INVITE
200 OK
INVITE200 OK
:::BYE
200 OK
MSRP 200 OK MSRP 200 OK
200 OK 200 OK
P/I/S-CSCFP/I/S-CSCF
MSR
PSI
PSI
P
BYE BYE
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS for Presence, Push 2 Talk, IM• Example IMS Service Architecture for the IMS services:
– Presence, – Push-to-Talk (PTT),– Instant Messaging (IM)
ApplicationsA
pplic
atio
ns
152
• In June 2002, the mobile industry set up a new, global organization called the Open Mobile Alliance (OMA)
–www.openmobilealliance.org• The Open Mobile Architecture initiative supporters and the WAP Forum
formed the foundation for the Open Mobile Alliance• The following organizations have integrated into OMA:
– Location Interoperability Forum (LIF)– SyncML Initiative– MMS-IOP (Multimedia Messaging Interoperability Process)– Wireless Village – Mobile Gaming Interoperability (MGIF)
– Mobile Wireless Internet Forum (MWIF)
• Other industry forums focusing on interoperability and open standards are welcome to join
Open Mobile Alliance (OMA)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
OMA Service Enablers and IMS
• IMS provides the following:– Routing and reachability– Authentication and transitive trust– Signaling compression– Privacy– User profile storage– Charging, accounting– Interface to the access network
• OMA SIP-based service enablers are specifiedon top of IMS as common platform, e.g.– Presence, Group Management, etc.
Standards
OMAforApplicationEnablers
3GPPforNetworkArchitecture
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
OMA Service Enablers and IMS
OMA service enablers
IMS
PoC Messa-ging
Otherenablers
IP Transport
ISC
Regist-ration
SessionControl Charging
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Push to Talk over Cellular (PoC)• PoC is standardised in the Open Mobile Alliance (OMA), Rel. 1 in 2005• First specification process was initiated by the MENSA (Motorola, Ericsson,
Nokia, Siemens, AT&T Wireless) consortium in 2002, 2003• PoC is a way of communication that uses half-duplex connections
– similar to walkie-talkie functionality– allows to deliver a talk burst to a collection of users
• PoC client is (usually) in the handset as a soft client• PoC server has ambiguous functionality: It manages both the signalling and
also the media– By definition the PoC server is acting as a SIP AS, connecting to IMS CN through
the ISC interface• OMA PoC does not consider access network issues (any access network can
be used)• OMA PoC requires the XML Document Management (XDM) enabler for group
session configuration• OMA PoC may use OMA XDMS architecture for presence as a presence
enabler• Dedicated floor control messages are used to grant access to the floor to
ensure semi-duplex paradigm
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
MENSA PoC Architecture Rel. 1 (2002)
• Introduction of Group List and Management Server
• No presence functionalityrequired
• No Network-NetworkInterworking (NNI)
• No automated deviceconfiguration
Source: PoC MENSA Rel. 1.1
UE
Im
PoC
Ser
ver
ACC
ESS
GLMS
IMSCore
(CSCF/HSS)
Presence Server
Ipl
Ips
Ik
IfIf
It
(talk)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
UE
OMA PoC Architecture Rel. 1 (2005)
• Introduction of OMA Enablerarchitecture forPoC
• XML DocumentManagement Enabler
• Alignment of PoCArchitecture to OMA enablerconcept
• Presence Enabler• Device
Management Enabler
• NNI
Used Protocols:• SIP• RTP/RTCP• RTCP• XCAP
Source: OMA/PoC Candidate Version 1.0
DM-1
Rem
ote
PoC
Net
wor
kR
emot
e Po
CN
etw
ork
ACC
ESS
NET
WO
RK
SIP
/ IP
Cor
ePresence
Server
PoC-7
PoC-3
DMServer
XDM-3
PRS-3
PoCServer
PRS-5
IP-1
XDMC
PRS-1
PRS-2
PoC-1
Aggregation Proxy
PoC-6XDM-1
PoC-2PoC-8
PoC-4
Shared XDMS
XDM-2
XDM-4
XDMC
XDM-3
PoC-5
DMClient
Presence Source
Watcher
PoCXDMS
PoCClient
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
From PTT to Community-Support
• PoC/PTT basically defines a specific service based on genericenablers (Presence, GLMS/XDMS, FOTA)
• Infact PoC/PTT could be regarded as a specific instantiation of a groupcommunication framework
• Making money with PoC/PTT is unclear• Making money with SMS and voice calls is clear• Idea:
– Reuse PoC/PTT enablers for other communication services as wellIntegrated Presence driven IM, email, SMS, MMS, VoIP, CS-Calls,
Video calls, etc.– Provide group communication to those who really need it
well established Communities (Sports, Work, health, fun) will appreciate this!
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS is a perfect basis for eCommunity services
• IMS is today considered as the common platform for FMC and NGNs
• A convergent community-service can ideally be based on the IMS platform granting:– convergence and compatibility
between fixed/mobile networks– multi-media and converged
services support– providing key community service
enablers, such as• Group Management• Presence• IM / PoC• generic VoIP/MMoIP support,
etc.
All-IP Network
IMS
Cellular Networks Fixed Networks
3GPP Domain NGN Domain
IMS
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
eCommunities - sooooo many Options
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Summary & Q&A
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Introduction Challenges
– IMS Integration Challenges• Core Network, SCE&SDP, OSS/BSS, Charging System
ChargingSystem
OSS /BSS ?
Core NetworkInfrastructure
Applications SCE and SDPInfrastructure
?
?
?
IMS
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Wireline IMS Introduction
164
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Wireless IMS Introduction
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Platform for migration to next-
generation network
Platform for fixed-mobile convergence
IMS Deployment Contexts
Platform for specific
service(s)
Project timescale
Project capex
166
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS Deployment Worldwide
Source: visiongain
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS to „unglue“ the value chain
Value AddedServices
NetworkTransport
• Tight vertical integrationof network and services
• Limited access for 3rd Parties(MVNO, Service Provider)
• Operators struggle to offerattractive service portfolio
GSM value chain
IMS value chain
NG Service NetworkProvider
NetworkTransport
Service/ApplicationProvider
• Loose vertical integration of networks, services and applications
• Standardized interfaces alloweasy integration of partners
Focus on core competenciesand economies of scaleEnriched service offerings fortarget communities
„wholesale“ „retail“
168
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Flatrates enable reasonable VoIP/Internet Access
WLO
TelcoPSTNxDSL
WLAN
LANEnterprise
MNOUMTSGPRS
Internet Service ProvidersAccess Network Providers
InternetApplication
Servers
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS as enabler for providing VA Internet Service
WNO
TelcoPSTNxDSL
WLAN/WiMax
LANEnterprise
MNOUMTSGPRS
Internet Service ProvidersAccess Network Providers
UnsecureInternet
Applications
Secure IMSApplications
IMS Value Prepositions:-Security-QoS-Flexible Charging-Plug & Play
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
MNO providing Fixed Mobile Convergence
WNO
TelcoPSTNxDSL
WLAN/WiMax
LANEnterprise
MNOUMTSGPRS
Internet Service ProvidersAccess Network Providers
UnsecureInternet
Applications
MNO FMC IMSApplications
Partnerships
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
NGN, IMS and SDPs
Mobile Access Networks
(GSM, GPRS)
Fixed Access Networks
(PSTN/ISDN)
Cable / TV Networks
Fixed and Mobile Internet Access
IP Core NetworkBearer Cotrol (QoS)
Seamless Applications & Content (FMC)
Service Enablers
Session Control
IntelligentNetworks/ CAMEL
VoIPSIP ServersAAA Servers
InternetWeb Servers
JavaJAIN
CORBA / C++OSA / Parlay
SOAWeb Services
IP MultimediaSystem
NGN
NGN
SDP
172
GSM
GPRSEDGE
UMTSIMS
CDMA
WiFi
Satellite
Mobile AccessMobile Access Fix Access Fix Access
PSTN Cable
xDSL
Public networkPublic network
DECT
WiFi
Mobile AccessMobile Access Fix Access Fix Access
LAN
PBX
Private networkPrivate network
IPIP--BackboneBackbone
DB
Control Layer(MSC-Server, CSCF, AAA,..)
HLRHSS
App1App1App1VASP
SMSCUSSD Gw
LBS
IVR
MMSC
OTA
ContentDelivery
MRF
MediaGW
Service Execution Environment
App1 App2 App3
MRFPresence
ExposureOSA
Parlay /XOMA
SDPSDP
Abstraction Layer
Internetwwwwww
GoogleGoogle
blogsblogs
PortalsPortals
SkypeSkypeicqicq
GamingGaming
33rdrd Party ASPParty ASP
Sup
ervi
sion
Pro
visi
onin
gB
illin
gC
RM
Ope
ratio
n &
Mai
nten
ance
Access Network Layer
Connectivity Layer
Control Layer
ExposureLayer
Service Execution Environment
Service CreationEnablers(incl. Content
Delivery)
Abstraction Layer
Service Delivery Platform = Horizontal Layers
IMS
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
SDP Technology Maturity Level
Introduction Growth Maturity Decline
Limitedcommercial deployments
Limited trials and technology evaluation
IMS
OSA/Parlay IN
Commercial deployments
Market acceptanceMature technology
Massive deployments
WebServices
Growingcommercial
deployments
174
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Overview
• Market Drivers for FMC• NGN and related Standard Bodies• The IMS as universal SDP• IMS Core Layer• IMS Applications Layer• IMS Introduction Strategies and Deployment Issues• The FOKUS Open IMS Playground as market driven NGN R&D Testbed• Q&A
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Fraunhofer FOKUS Facts
– FOKUS has been founded 1988 in Berlin, Germany– 220 employees: scientists, students, technicians
originating from 30 nations
– FOKUS is THE Telecoms R&D institute within theFraunhofer Society
• Fraunhofer Society is the biggest German R&D organisation, total # of 12.000 employees)
• 60 institutes in total, 15 institutes in ICT
– FOKUS works since 17 years on convergence of IT, telecoms, internet and homeentertainment and performs applied research and development projects
• Performs strategic studies, solution concepts, system integration and prototypdevelopments
• Strong cooperation with universities & Establishment of spin offs (e.g. iptelorg.com)
– FOKUS fundung: 20% state, 80% industry R&D projects
• Key to success: Strategic Partnerships with big players (DTAG, NTT, etc)
– Main R&D Vision: „I-centric communications“ and „autonomic communications“
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Nat. Open 3Gb Test & Development Center– Provision of a unique 3Gb Testbed covering all
three 3G beyond layers– Foundation for industrial and academic projects
• Applications development support• Applications validation• Service Platform prototyping• Infrastructure component testing• Network Technologies integration• ....
– Officially supported by
Applications
UMTSFDD/TDD
GSM /GPRS
WLANa/b/x
DVB-S/T
weitere
3Gb Network Technologies
Service Platforms& Middleware
mGov
OtherNetws
Parlay
3Gb Roaming
SIPAAAIMS
weitere
Web services
Otherplatforms
mHealth mXXX. weitereweitereOtherApps
Eng
inee
rin
g T
oo
ls,C
on
form
ance
Test
ing
, M
easu
rmen
ts, a
nd
Man
agem
ent
European 3Gb R&D Projects
National 3Gb R&D Projects
NGN Testbed @ Fraunhofer FOKUS
Parlay Playground
IMS Playground
www.fokus.fraunhofer.de/national_host
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
IMS playground @ FOKUS
• forms a globally unique state of the art IMS infrastructure featuring all majorIMS componentsand interfaces
• is a key infrastructure of the FOKUS NGN Service Delivery Platform test and development center
• comprises– a full IMS based on own developments– additional best of bread carrier grade components from partners
• Goals:– Provision of an open IMS platform and planned interconnection to
Operator IMS test beds– Interoperability test of IMS components (S-CSCFs, Media Gateways, SIP
AS, etc.)– Environment for development of new MM applications, application
platform extensions and IMS mobility, QoS and security reasearch• Contact: www.fokus.fraunhofer.de/ims
178
T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
OPEN IMS Playground Overview
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
FOKUS – developed IMS Components
• IMS Core– Call Session Control Functions
• SIP proxy with 3GPP features - SER– Home Subscriber Server
• Diameter based AAA Server- FHoSS– Media Server
• Media Streaming – SEMS
• IMS Application Layer– IMS compliant SIP Clients – OSC– Application Server
• SIP Servlet AS – SIPSEE• Parlay X Gateway – OCS-X• Parlay Gateway – OCS
180
Motivation for an Open Source IMS Core
• IMS is in trial phases with telco and cable operators worldwide• R&D efforts for NGNs are gaining support• While there are already many Open Source projects established in the
plain VoIP area for – SIP clients – SIP proxies – SIP stacks – SIP (testing) tools
around the standard, there are currently practically no Open Source projects with specific focus on the IMS
• FOKUS is aiming to fill this void
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Open IMS Core – Components
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Call Session Control Functions
• CSCF = SIP proxy to route and process the SIP signaling
– Proxy-CSCF • outbound proxy for User Endpoints – entry point in the IMS network• keep local registrar and firewall the core network• add important network/charging/etc information to the messages• bridge between access network (visited network) and user’s home network
– Interrogating-CSCF• entry point in the Home Network• originating/terminating party assigned Serving-CSCF retrieval• stateless forwarding of messages
– Serving-CSCF• local registrar for served users• authenticate the users • subscription server for registration status events• evaluate Initial Filter Criteria and route messages accordingly to Application Servers for service
processing
I-CSCF
S-CSCF
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
HSS & SIP2IMS Gateway
– Home Subscriber Server• evolution of a Home Location Register to the all-IP core network• stores user profile, provisioning data• keeps registration status• keeps location information
– SIP2IMS Gateway• allows transformation of IETF SIP messages to IMS conformant messages• Translates MD5 authentication to IMS AKA authentication
HSS
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Elements around the Open IMS Core
Functionalitly of the Open IMS Core can be verified with additonalcomponents
– IMS UE• must be capable of performing IMS AKA registration• IMS specific SIP behaviour e.g. subscription to own registration event
– SIP client• uses IETF SIP protocols without IMS extensions (e.g. Kphone, eyebeam)• attaches to IMS Core via SIP2IMS Gateway
– Application Servers • tested Service platforms for the Open IMS Playground
• SIPSEE (SIP AS)• Open Coummincation Server (Parlay Gateway) • Open Communication Server X (Parlay X Gateway)
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006Specification Guidelines for the Open SourceIMS Core
• IETF RFCs (selection)– SIP: Session Initiation Protocol – RFC 3261– Hypertext Transfer Protocol (HTTP) Digest Authentication Using Authentication
and Key Agreement (AKA) - RFC 3310– SIP Private Header Extensions - RFC3455– Diameter Base Protocol – RFC 3588– SIP Event Package for Registration - RFC3680
• 3GPP IMS Release 6 Specifications (selection)– TS 23.228 – IMS Stage 2 (Rel.6)– TS 24.229 - IP Multimedia Call Control Protocol based on Session Initiation
Protocol (SIP) and Session Description Protocol (SDP); Stage3 (Rel.6)– TS 29.228 – Cx and Dx Interfaces, Signalling flows and message contents
(Rel.6)– TS 33.102 - 3G Security; Security architecture (Rel. 6)– TS 33.203 - Access security for IP-based services (Rel.6)
186
The Open Source IMS Core
• A version of the Open IMS Core is currently being developed and was already successfully tested with commercial IMS products. It– provides first time implementations of core IMS components
• Call Session Control Functions• Home Subscriber Server
– offers an Open Source IMS platform to make use of the ISC interface– can act as a tool for IMS services proof-of-concept – allows to test alpha/beta versions of commercial IMS products– does not intend to compete with carrier grade developments but wants to
create an Open IMS community and to accelerates IMS adoption– release of the CSCFs scheduled for end of 2006 via the BerliOS
(www.berlios.de) platform
• For further information please contact{weik,vingarzan}@fokus.fraunhofer.de
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T. Magedanz (TU Berlin / Fraunhofer FOKUS) - 2006
Integration of Partner Components @ FOKUS IMS PG
Not
e: T
his
isno
ta c
ompl
ete
Part
ner L
ist!
XDMS Presence
Testing
188
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Reference Customers
– Consulting on IMS development strategies for major vendors– Consulting on bids and gap analysis of commercial products for key
global integrator– Extensions (Interfaces/Reference Points) of commercial solutions of
various vendors– Implementation of prototypes for vendors and operators– Integration and Compliancy testing of commercial solutions– Consulting on IMS integration strategies for major German Operator– Interoperability testing for major European vendors– IMS Load- /Perfomance testing for key global hardware vendor– Application Service development for major German operator– Consulting for establishing IMS Testbeds at remote sites – Plus German and European R&D projects on Feature Interaction and
Service composition
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FOKUS Work Areas in IMS/NGN
Open IMS Playground
Open SourceIMS Core
IMS Application
Server&Client
IMSBenchmarking
& InteroperabilityTools
VoIP / IMSSecurity
& Reliability
IMS Data
ManagementHSS
FMC / NGNApplicationsPrototyping
Consulting forOperators& Vendors
InteroperablityTesting &
Benchmarking
R&DProjects
FMC / IMSHandover
IMS /DVBIntegrationTriple Play
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3GPPETSIOMA IETF ITU-T
ContributionTo
Standards
FOKUS NGN/IMS R&D Focal Points
DifferentAccess Networks
(WLAN, UMTS, DSL)
Interworking withLegacy Networks(GSM, ISDN, DVB)
NGN All IPCore Network
IP MultimediaSystem (IMS)
NGN Application Servers / APIsMM Content DeliverySingle Sign On (HSS)Service Orchestration
Model Driven Architecture(MDA)
Content & Services
Development of necessary Services
Client Software
Integration of different Access Networks
QoS Provision & Security
Interworking with other networks
IMS Management + AAAIMS Conformance Tests
Scalability & Performance
www.fokus.fraunhofer.de/IMS
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Summary
• IMS – is an overlay service network architecture applicable to any IP network
(GPRS, UMTS, WLAN, DSL, ..) based on internet standards (IETF)– is a global standard (supported by 3GPP, 3GPP2, ETSI, OMA, IETF)– can be considered as THE universal Service Delivery Platform for NGNs
supporting also Fixed Mobile Convergence (FMC)• IMS should be mainly considered as a service enabler (i.e. no real IMS
services are standardised!)• Push to Talk / PoC can be regarded as first IMS real life proof of
concept• But biggest service potential is in Community-based services• FOKUS provides knowhow and a powerful infrastructure for testing
IMS components and prototyping IMS / NGN services
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Any Questions?
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IMS ReferencesTS 23.228 Archi IP Multimedia Subsystem (IMS); Stage 2 S2TS 33.203 Security Access Security (& integrity protection) for IP-based Services”, Stage 2 S3TS 33.210 Security Netw. domain sec.; IP network layer security (sec of SIP signalling between network nodes) S3TS 23.218 Call Control IP Multimedia (IM) session handling; IM call model; Stage 2 N1TS 24.228 Call Control Signalling flows for the IMS Call Control based on SIP and SDP; Stage 3 N1TS 24.229 Call Control IP Multimedia Call Control Protocol based on SIP and SDP; Stage 3 N1TS 26.235 User plane Packet Switched Conversational Multimedia Applications; Default codecs S4TS 26.236 User plane Packet Switched Conversational Multimedia Applications; Transport protocols S4TS 29.162 Interworking Interworking between the IM CN subsystem and IP networks N3TS 29.163 Interworking Interworking between the IM CN subsystem and CS networks N3TS 23.278 Service Logic CAMEL - IP Multimedia System (IMS) interworking; Stage 2 N2TS 29.278 Service Logic CAMEL Application Part (CAP) specification for IP Multimedia Subsystems (IMS) N2TS 29.228 User data & interfaces IP Multimedia (IM) Subsystem Cx and Dx Interfaces; Signalling flows and message contents N4TS 29.229 User data & interfaces Cx and Dx interfaces (based on Diameter) Protocol details N4TS 29.328 User data & interfaces IP Multimedia Subsystem (IMS) Sh interface signalling flows and message contents N4TS 29.329 User data & interfaces Sh interface based on the Diameter protocol N4TS 22.115 Charging Charging & Billing, Stage 1 S5TS 23.815 Charging Charging implications of IMS architecture S2/S5TS 32.225 Charging Charging data description for the IMS - Rel 5 S5TS 32.260 Charging IMS Charging - Rel 6
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