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Converged Fixed-Mobile solutions:The TISPAN_NGN approach
(Sophia, 22 November 2004)
Christian Julien(ETSI Secretariat)
TC TISPAN TOchristian.julien@etsi.org
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Agenda
1.1. TISPAN_NGN Project: Steps and TISPAN_NGN Project: Steps and RequirementsRequirements
2. TISPAN_NGN Status: architecture outline3. How the use of 3G UMTS IMS in NGN will help
Fixed-Mobile convergence for Multimedia4. Some important issues to be taken care of5. Summary
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TISPAN_NGN Genesis
TISPAN: TTelecommunication and IInternet converged SServices and PProtocols for AAdvanced NNetworking
results from the combination, in September 2003, of : SPAN, formed as a Technical Body from the joining of SPS
(Services, Protocols & Switching) and NA (Network Aspects)
TIPHON, formed in 1997 as an ETSI Project to study VoIP and subsequently extended to any Telecom (including Multimedia) services over IP
TIPHON = Telecommunications and Internet Protocol Harmonization Over Networks
SPAN = Services and Protocols for Advanced Networks
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TISPAN_NGN Synergy
The working groups of the TC TISPAN have been carefully defined to cover the needs of the industry in specific technical areas of competence
Each project follows a particular technical subject and co-ordinates across the competence groups
The following slide gives an summary of the way the new TC leads the way in standardisation
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TISPAN_NGN Synergy
SERVICES
ARCHITECTURE
PROTOCOLS
NUMBERING &ROUTEING
QoS
TESTING
Tisp
an_N
GN
F-M
MS
Tele
com
Equ
ipm
ent I
dent
ity
Etc… as needed
NETWORK MANAGEMENT
EMTE
L (E
Mer
genc
y TE
Leco
mm
unic
atio
n)
DTM
(Dyn
amic
asy
nchr
onou
s Tr
ansf
ert M
ode)
SECURITY
Projects8 Working Groups
OSA
(Ope
n Se
rvic
e A
cces
s)
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Technical approach
Nam
ing &
Addressing
Net
wor
k &
Ser
vice
Man
agem
ent
Security
Protocols, Interworking etc.
Testing
Services
Capabilities
Architecture & Requirements
Goals
Definition
Specification
Typical Services and basic features
Service Capabilities (building blocks)
QoS, Security, Naming and Addressing
Architecture and Requirements
Network and Service Management (NGN OSS)
Protocol Selection and Profiling
Evaluation & Modification (“fit for purpose”)
Test Specification and Test Suites (to facilitate interoperability)
QoS
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_NGN goals & Technical overview The Next Generation Network will eventually
provide: A multi-service multi-protocol, multi-access, IP based network
- secure, reliable and trusted• Multi-services: delivered by a common QoS enabled core
network. • Multi-access: diverse access networks; fixed and mobile
terminals,• Not one network, but different networks that interoperate
seamlessly An enabler for Service Providers to offer
• real-time and non real-time, communication services • between peers, or in a client-server configuration.
Nomadicity and Mobility• of both users and devices• inter and inter-Network Domains, eventually between Fixed and
Mobile networks
“My communications services” always reachable, everywhere, using any terminal.
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_NGN Wide range of services
Messaging
Person-to-Person – Communication Services
Content-on-demandBrowsing Download Streaming PushBroadcast
Peer-to-Peer
Conversational Voice call Video call
Chat call Multimedia call
e-MailSMS EMS
MMS
IM
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Conversational Streaming TV Broadcasting Messaging Web
Support of a wide variety of services
Support of fixed and mobile converged services
Control Functions
Packet-based transfer
DSL/ATMDSL/Ethernet UTRAN/GPRS
Backbone
Cable NetworkWLAN
Well defined interfaces between control and applications
Independence between control and transport
Support of a wide variety of terminals
_NGN key assumptions
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_NGN high level Roadmap
2006
Towards a converged Wireline and Wireless NGN …Release 3
2007 2008
Release 1 Release 2
200920052004
xDSL,WLAN FTTx Fully
Nomadic
Release 1 bringing Multimedia services Nomadicity/user-controlled roaming xDSL access focus; Access Network Attachment Subsystem
Release 2 optimizing access resources usage According to user subscription profile and service use Corporate users specific requirements …
Release 3 introducing full (inter-domain) Nomadicity Inter-network domain nomadicity/user-controlled roaming Higher bandwidth access (VDSL, FTTH, Wi-max …)
???
2010
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Agenda
1. TISPAN_NGN Project: Steps and Requirements
2.2. TISPAN_NGN Release 1 Status: TISPAN_NGN Release 1 Status: architecture outlinearchitecture outline
3. Why the use of IMS in NGN will help Fixed-Mobile convergence for Multimedia
4. Some important issues to be taken care of5. Summary
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_NGN Release 1 scope Ongoing discussion
Being consolidated meeting after meeting Stabilized at TISPAN#4 (sept.) & #4bis (nov.) meetings
Major service capabilities under consideration Real time conversationnal services (Voice, Videotelephony) Messaging (Instant Messaging, MMS), Presence Management Legacy services emulation enabling legacy PSTN/ISDN
migration towards NGN Content delivery such as VOD, Video Streaming, TV-Channel
distribution (if inputs and resources available) Network Architecture basis
ADSL access prime focus, possibly WLAN (may be deferred to Release 2)
3G/UMTS IMS sub-system reused as basis for real-time Conversationnal services (SIP-based session control)
Objective: mid-2005 Pragmatic bottom-up approach for Release 1 Not excluding Top-down (TIPHON-like) approach for preparing
future TISPAN_NGN Releases
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_NGN architecture design principles A sub-system oriented approach, enabling:
The addition of new subsystems over the time to cover new demands and service classes.
To import subsystems from other standardisation bodies.Flexibility to adjust the architecture.
IP connectivity is provided using two subsystems:Network Attachment Subsystem (NASS)Ressource and Admission Control Subsystem (RACS)
First service-oriented subystems include:The 3GPP IMS suitably adapted to accomodate xDSL-based access networks requirements (joint effort with 3GPP), supporting multimedia services and PSTN/ISDN Simulation.
A PSTN/ISDN Emulation subsystem specifically tailored to allow TDM equipment replacement, while keeping legacy terminals unchanged.
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_NGN Architecture overview
Other MultimediaSubsystems …
Based on3GPP IMS R6
(RTSP -based)Streaming services
(SIP -based) IP Multimedia Subsystem
(Core IMS)
IP ConnectivityAccess NetworkAnd related functionality
PSTN
(SIP - I based)PSTN/ISDN Emulation
Subsystem
Applications
IP
Resource and Admission Control
Functionality
Core Transport Network
Access TransportNetwork
GWGWGW
Network Attachment Functionality
GW
3GPP IP-CAN
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Resource and Admission Control Functionality
RACS
Based on3GPP IMS
IP ConnectivityAccess NetworkAnd related functionality
Network AttachmentFunctionality
NASS
Other Multimedia Components …
Streaming Services (RTSP based)
PSTN / ISDN Emulation(SIP-I based)
Applications
Core transport Network
3GPP IP-CAN
Access Transport Network
IP
3GPP Terminals
NGN Terminals
LegacyTerminals
CustomerNetworks
DataBase
Other N
etworks
“Gq”interface
“Go”interface
IP Multimedia Component (Core IMS)
(SIP based)
PSTN
/ ISDN
MBG
TGW
ICF
GW
GW
LegacyTerminals
NGN Terminals
LegacyTerminals
_NGN detailed overview
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IMS introduced in 3GPP Rel5, and further enhanced in Rel6:IP Multimedia domain for call control based on SIP3GPP specifies features to fullfill operator requirements, e.g.:
•QoS control•Charging•Security•Subscription profiles•Interworking with other networks (CS/PSTN)
IMS provides building blocks allowing faster integration and deployment of IP multimedia services
IMS background (1/3)
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IMS allows operators to have more control on the service level than with GPRS only:Service level awarenessCorrelation between the SIP application layer and the transport in PS domainAccess to services in correlation with a subscription profile (e.g. basic, silver, gold…)Better control on the packet resources used
3GPP IMS Releases:Release 5: frozen since March 2003Release 6: freezing in December 2004Release 7: Starting. Stage 1 requirements being currently defined
IMS background (2/3)
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User IdsUser profile
security roaming
Inter-WorkingCS/PSTN
QoS policycontrol
BasicCall
ControlService logic
APIs
SIP
charging
IMS background (3/3)
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Signaling path Content path
LegendIMS SIP: CSCF Call State Control
FunctionsProxy- UE Interface, Local
ServicesInterrogating- Home Network
Contact PointServing- Session Control,
Service Invocation, AS & HSS Trigger, Charging, …
Call Flow
1 Register & find user Home
2 Register & Retrieve required S-CSCF & it’s capabilities
3 Choose correct S-CSCF
4 Register & Download IMS user Profile
5 INVITE UE#2 into call
6 Upon Acceptance, Data Path is Set-up
UMTS PACKET DOMAIN
UMTS PACKET DOMAIN
ApplicationServers
P-CSCF
I-CSCF
S-CSCF
IP MULTIMEDIA SUBSYSTEM
GGSNGGSNSGSN SGSNUE #1 UE #2
1
2 3
4
5
6
IMS Registration and Call
HSS
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IMS
IMS Architecture
UTRAN
SGSN GGSNUE
PS Domain
I-CSCF
Go Gi
I-CSCF
P-CSCF S-CSCFMw
HSS
Cx
Cx
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)
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 external IP 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 Plane
Control Plane
Other IP/IMS network
Mm
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IMS
IMS Architecture
UTRAN
SGSN GGSNUE
PS Domain
I-CSCF
Go Gi
I-CSCF
P-CSCF S-CSCFMw
HSS
Cx
Cx
SGWMGCF
BGCF
IMS-MGW
Legacy/PSTN
Mk
MiMg
Mj
MnGi
MRF
Gi
Mr
PDFGo
GqThose entities are responsible for interworking between IMS and CS domain/PSTN
In Release 6, the PDF can be separated from the P-CSCF. Those two entities are then connected through the Gq interface.
The MRF is used for multiparty
call control
Traffic Plane
Control Plane
Other IP/IMS network
Mm
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Resource and Admission Control
Subsystem
PSTN/ISDNOther
subsystemsIMS
PSTN/ISDN Emulationsubsystem
Applications
Customer Prem
ises Equipment
Service Layer
Transport Layer
Transport Functions
Network Attachment Subsystem
_NGN IMS-based subsystem
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Core IMS use in the NGN architectureO
ther IP Netw
orks
IP Transport (Access and Core)
T-MGF
I-BGF
AS HSS
IBCF
A-BGF
P-CSCF
S-CSCF
BGCF
I-CSCFSLF
ChargingFunctions
IWF
UE
«Core IMS »Mw
Mw Mw/Mk/Mm
MrMg
Mj
Mi
Mp MnGm
Gq
ISC Cx
Dx
Dh
Sh
Ic
Rf/Ro
Rf/RoCxIb
Ia
Id
PSTN/ISD
N
SGFMRFC MGCF
MRFP
Resource and Admission Control Subsystem
Network Attachment Subsystem
If
Ie
Mi
Mw
Other IP N
etworks
IP Transport (Access and Core)
T-MGF
I-BGF
AS HSS
IBCF
A-BGF
P-CSCF
S-CSCF
BGCF
I-CSCFSLF
ChargingFunctions
IWF
UE
«Core IMS»Mw
Mw Mw/Mk/Mm
MrMg
Mj
Mi
Mp MnGm
Gq
ISC Cx
Dx
Dh
Sh
Ic
Rf/Ro
Rf/RoCxIb
Ia
Id
PSTN/ISD
N
SGFMRFC MGCF
MRFP
Resource and Admission Control Subsystem
Network Attachment Subsystem
If
Ie
Mi
Mw
SIP
DIAMETER
H.248
impacted
NGNspecific
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_NGN standards built on 3GPP IMS specs
Use the “core” IMS as one of the high-level components of the overall NGN architecture, with initial focus on xDSL
xDSL-based access networks provide access to IMS and other subsystems (e.g.; streaming)
xDSL-based access networks as a new type of IP-Connectivity Access Network for the IMS
Complement the IMS with other subsystems A resource and admission control subsystemA network attachment subsystemA PSTN/ISDN Emulation SubsystemOther multimedia subsystems and applications
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Differences between xDSL and 3G Radio Access
Differences which impact the IMS-SIP specifications:Wireline versus Wireless: The constraints in terms of bandwidth scarcity, security, transmission delay are different
Terminals: Less stringent requirements are likely to be placed on NGN terminals (e.g. support of IPv6, availability of USIM/ISIM, codecs...)
Location Information: Location information is different in nature and usually not available at the UE
Resource management:: Explicit resource reservation signalling not available in terminals and access network edge points; no dedicated channel for signalling
Regulatory issues: Different contexts leading to different constraints
Terminals vs Users: Users are not always tied to terminals
Details being discussed between 3GPP (IMS R6 and R7) and TISPAN
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IP Connectivity control
IP connectivity is provided using two control subsystems, which play a role similar to the 3GPP GPRS procedures
Network Attachment SubsystemIP address allocation (e.g.; using DHCP).Authentication, taking place at the IP layerAuthorisation of network accessLocation management, taking place at the IP layer,...
Ressource and Admission Control SubsystemAdmission ControlGate Control ...
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_PSTN/ISDN Emulation Subsystem
Resource and Admission Control
Subsystem
PSTN/ISDNOther
subsystemsIMS
PSTN/ISDN Emulationsubsystem
Applications
Customer Prem
ises Equipment
Service Layer
Transport Layer
Transport Functions
Network Attachment Subsystem
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Emulation vs SimulationPSTN/ISDN service continuity in NGN: PSTN/ISDN Simulation
"Provides PSTN/ISDN service capabilities and interfaces using adaptation to an IP infrastructure"
The provision of PSTN/ISDN-like services to advanced terminals (IP-phones) or IP-interfaces. There is no strict requirement to make all PSTN/ ISDN services available or identical, although end users expect to have access to the most popular ones, possibly with different ergonomy.
PSTN/ISDN Emulation "Provides PSTN/ISDN-like service capabilities using session
control over IP interfaces and infrastructure" Mimicking a PSTN/ISDN network from the point of view of legacy
terminals (or interfaces) by an IP network, through a gateway. All PSTN/ISDN services remain available and identical (i.e. with the same ergonomics); such that end users are unaware that they are not connected to a TDM-based PSTN/ISDN.
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_PSTN/ISDN Emulation subsystem
Two approaches under discussion: Softswitch approach ('Monolithic architecture')
•A shortcut to refer to (often already existing) implementations based on use of call control software (ported from legacy switches).
•Not requiring standardisation of the internal structure of the PSTN/ISDN emulation subsystem, only external interfaces
IMS-like approach•Re-use (all or part) of the IMS functional architecture to specify the
internal structure of the PSTN/ISDN Emulation subsystem
Towards a compromise agreement: Functional architecture, physical implementation examples
•Standardisation of external interfaces: H.248 profile, network SIP-IAn IMS-like functional architecture does not prevent the implementators to build a physical architecture using only softswitches (MGC) and media gateways (MGW).
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IMS and PSTN/ISDN Emulation Many similarities
Two session-based control subsystems: •For supporting multimedia conversational services and PSTN/ISDN
services simulation (IMS)•For supporting PSTN/ISDN services emulation
Above a managed IP network Supporting operators’ requirements
•Quality of service, Security, Charging capabilities, Regulatory constraints....
Clear Benefits Enables the deployment of common control platforms
•Towards a unique infrastructure for supporting multimedia services and TDM- switches replacement
Enables service convergence •new voice services available to all types of subscribers
Enables the scope of nomadism to be extended to legacy access lines.
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SIP may also be used if the set of services to be emulated is limited and/or « downgraded » emulation is considered acceptable (e.g. second line).
_Emulation typical configurations
Z H248 ZH248SIP-I
RGW or AGW
RGW or AGW
Z H248 H248SIP-I
RGW or AGW
S/T
DSS1/IUA
Z H248
H248
SIP-I
RGW or AGW
TGW
ISUP
PSTN/ISDN
H248SIP-I
RGW or AGW
V5.2V5.2/V5UA
ANZ H248
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Resource and Admission Control
Subsystem
PSTN/ISDNOther
subsystemsIMS
PSTN/ISDN Emulationsubsystem
Applications
Customer Prem
ises Equipment
Service Layer
Transport Layer
Transport Functions
Network Attachment Subsystem
_Network Attachment Subsystem
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Main functionalitiesIP address allocation (e.g.; using DHCP).Authentication and authorisation, taking place at the IP layerAccess network configuration, based on user profiles.Location management, taking place at the IP layer
Replaces the 3GPP PS Domain / GPRS procedures for authentication and location management
Outstanding Issues Interactions between authentication at the network attachment level and at the SIP level.
Alignement with DSL Forum ArchitectureOne NASS per access network or one NASS for several access networks?
_Network Attachment Subsystem
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a4
Service control subsystems and
applications
TE CNG
a3 a1
a2
e1
e2 e4
e3
Resource and
Admission Control
Subsystem
CLF
NACF CDCF
AMF
PDBF UAAF
_NGN NASS current architecture
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Resource and Admission Control
Subsystem
PSTN/ISDNOther
subsystemsIMS
PSTN/ISDN Emulationsubsystem
Applications
Customer Prem
ises Equipment
Service Layer
Transport Layer
Transport Functions
Network Attachment Subsystem
_Resource and Admission Control
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Main Functionalities:Session Admission Control.Gate Control (including NAPT)
TISPAN R1 : No interactions between RACS in different networks
Need to support both push and pull proceduresPush mode required for ADSL-based access networks
Issues for future releases:Admission control at core network boundaries.Cooperation between peer ressource control subsystems
_NGN RACS description
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Provides a Gq-like interface to TISPAN Subsystems and applications
Controls transport ressources at the boundary between the access and core networksUsing a Gate Control Protocol
May also control NAPT at core network boundaries TISPAN has recently approved an H.248-based
Gate Control ProfileAn alternative COPS-based or SNMP-based standards may be pushed by some vendors at a later stage
_NGN RACS status
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Agenda
1.1. TISPAN_NGN Project: Steps and TISPAN_NGN Project: Steps and RequirementsRequirements
2.2. TISPAN_NGN Release 1 Status: architecture TISPAN_NGN Release 1 Status: architecture outlineoutline
3.3. Why the use of IMS in NGN will help Fixed-Why the use of IMS in NGN will help Fixed-Mobile convergence for MultimediaMobile convergence for Multimedia
4. Some important issues to be taken care of5. Summary
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Why IMS in NGN ?
IP Multimedia Substem generally fulfills the NGN requirements for conversational services
For managed, carrier operated telecom networkWith Release 6 becomes applicable to a range of access network types (3G RAN, WLAN)
IMS access (technology) independence Whole Telecom industry benefit
Will enable simple and effective interworking between Cellular and Wireline
Growing IMS market, encouraging greater usageWider choice of IMS suppliersMarket stimulation, decreasing costs (thanks to shared development/deployment costs)
…
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Benefits of IMS use in NGN TISPAN_NGN has taken the lead in adopting 3G IMS as a key
base component in the NGN architecture It needs adaptions to support xDSL access (on-going) Still a number of issues to be addressed (Identifiers, Security,
IPv4/v6 interworking and transition …) A promissing major step to enable smooth Fixed-Mobile
convergence for Multimedia: Consolidating the IMS and Service Platforms access & transport
technology independence Enabling seamless service interworking An effective basis to support Nomadicity and Mobility features
Still a number of challenges ahead Resource optimization and transport technology evolution QoS insurance for Real time services … Identifiers, Security …
But a significant step is being taken to enable the Multimedia Fixed-Mobile convergence in TISPAN_NGN Release 1
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Agenda
1.1. TISPAN_NGN Project: Steps and TISPAN_NGN Project: Steps and RequirementsRequirements
2.2. TISPAN_NGN Release 1 StatusTISPAN_NGN Release 1 Status3. Why the use of IMS in NGN will help Fixed-
Mobile convergence for Multimedia4.4. Some important issues to be taken care ofSome important issues to be taken care of5. Summary
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_NGN IMS-related issues A promissing approach but many challenges, e.g.
Resource and QoS control in access (and end-end) QoS insurance (IP flow differenciation) Policy control (G0) interface
Services interoperability Services are not (yet) standardized in 3GPP TISPAN_NGN is intending to standardize a minimum set Interworking with Legacy networks and Platforms
Terminals IP addresses, (Line & Personal) Identifiers, SIP Client (Profile) …
IT adaptation and integration Flexible NGN-OSS Provisioning, Charging and Billing
To enable use of IT(IP)-based technology in Telecom carriers grade environment.
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Using Gq interface in NGN
Gq Interface is located between Multimedia Subsystem(s) and Resource and Admission Control Subsystem (RACS)
Gq is used by different subsystems (not only IMS) and multiple Access Networks
Gq is used to access the following functions: Resource reservation Admission Control NAT Control Gate and Policy Control
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Gq interface Extensions
Support for network initiated resource reservations Besides Pull Model the Push model shall be supported.
Support for requesting Address and Port Translation Parameters for NAT type of scenarios., e.g.
• interworking of different (private/public) IPv4 address spaces, query and allocate NAT bindings
• Possibly IPv4/IPv6 interworking Gate control and service and network policy control
Parameters to access those functions
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Agenda
1.1. TISPAN_NGN Project: Steps and TISPAN_NGN Project: Steps and RequirementsRequirements
2.2. TISPAN_NGN Release 1 Status: architecture TISPAN_NGN Release 1 Status: architecture outlineoutline
3. Why the use of IMS in NGN will help Fixed-Mobile convergence for Multimedia
4. Some important issues to be taken care of5.5. ConclusionConclusion
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_NGN summary A strong industry demand
For new generation Multimedia services on xDSL access For preparing replacement of soon becoming obsolescent PSTN
For a first Release of specifications by mid-2005 Giving main standards directions With realistic and implementable solutions
ETSI TISPAN taking the lead to propose an architecture basis consisting of a range of subsystems: Maximizing Wireline and Cellular convergence, through adoption of
3G/UMTS IMS component for support of conversational services Access network attachment Subsystem, Resource and admission
control sub-system … preparing for next Releases TISPAN collaborating with 3GPP to accommodate Wireline
access network requirements by IMS A 1st Workshop held last June, a further one next year To coordinate the IMS specifications evolutions to support various
Wireless and Wireline access technologies Other collaborations very welcome
ITU-T NGN Focus Group, ATIS is eager to cooperate European IST projects e.g. which is considering IMS in the
scope of their system architecture too.
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Acronyms
CSCF Call State Control Function IMS IP Multimedia Services IWF Inter-Working Function GPRS General Packet Radio Service HSS Home Subscriber Function MRF Multimedia Resource Function MGCF Media Gateway Control Function SIP Session Initiation Protocol SLF Subscriber Location Function UMTS Universal Mobile Telecom. System UTRANUniversal Telecom. Radio Access Net.
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THANKS FOR YOUR ATTENTIONTHANKS FOR YOUR ATTENTION
Questions/Comments ?
ETSI TISPAN Portal:http://portal.etsi.org/Portal_Common/home.asp