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Converged Fixed-Mobile solutions: The TISPAN_NGN approach (Sophia, 22 November 2004). Christian Julien ( ETSI Secretariat) TC TISPAN TO christian.julien@etsi.org. Agenda. TISPAN_NGN Project: Steps and Requirements TISPAN_NGN Status: architecture outline
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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
Agenda • TISPAN_NGN Project: Steps and Requirements • TISPAN_NGN Status: architecture outline • How the use of 3G UMTS IMS in NGN will help Fixed-Mobile convergence for Multimedia • Some important issues to be taken care of • Summary
TISPAN_NGN Genesis TISPAN:Telecommunication andInternet convergedServices and Protocols for Advanced Networking 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 SPAN = Services and Protocols for Advanced Networks TIPHON = Telecommunications and Internet Protocol Harmonization Over Networks
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
TISPAN_NGN Synergy 8 Working Groups Projects SERVICES ARCHITECTURE PROTOCOLS NUMBERING & DTM (Dynamic asynchronous Transfert Mode) EMTEL (EMergency TELecommunication) ROUTEING Tispan_NGN OSA (Open Service Access) Telecom Equipment Identity F-MMS QoS TESTING SECURITY NETWORK MANAGEMENT Etc… as needed
Technical approach Services • Typical Services and basic features Goals Capabilities • Service Capabilities (building blocks) • QoS, Security, Naming and Addressing QoS Security Definition • Architecture and Requirements Naming & Addressing Architecture & Requirements • Network and Service Management (NGN OSS) Network & Service Management • Protocol Selection and Profiling Protocols, Interworking etc. Specification • Evaluation & Modification (“fit for purpose”) • Test Specification and Test Suites (to facilitate interoperability) Testing
_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.
Person-to-Person – Communication Services Conversational • Voice call • Video call • Chat call • Multimedia call Messaging • e-Mail • SMS EMS • MMS • IM Content-on-demand Browsing Download Streaming Push Broadcast Peer-to-Peer _NGN Wide range of services
_NGN key assumptions Support of a wide variety of services Conversational Web TV Broadcasting Messaging Streaming Support of fixed and mobile converged services Well defined interfaces between control and applications Control Functions Independence between control and transport Packet-based transfer Backbone DSL/ATM DSL/Ethernet WLAN UTRAN/GPRS Cable Network Support of a wide variety of terminals
??? Fully Nomadic xDSL, WLAN FTTx Release 3 Release 1 Release 2 _NGN high level Roadmap Towards a converged Wireline and Wireless NGN … • 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 …) 2005 2008 2007 2009 2004 2006 2010
Agenda • TISPAN_NGN Project: Steps and Requirements • TISPAN_NGN Release 1 Status: architecture outline • Why the use of IMS in NGN will help Fixed-Mobile convergence for Multimedia • Some important issues to be taken care of • Summary
_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
_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.
Applications Based on 3GPP IMS R6 Other Multimedia Subsystems … IP Connectivity Access Network (RTSP - based) And related functionality Streaming services Network (SIP - based) Attachment IP Multimedia Subsystem Functionality (Core IMS) (SIP - I based) PSTN PSTN/ISDN Emulation Subsystem Resource and Admission Control Functionality GW GW GW GW Access Transport Network Core Transport Network IP 3GPP IP-CAN _NGN Architecture overview
Based on 3GPP IMS IP Connectivity Access Network And related functionality Legacy Terminals Core transport Network Access Transport Network 3GPP IP-CAN _NGN detailed overview Applications Data Base Other Multimedia Components … Streaming Services (RTSP based) IP Multimedia Component (Core IMS) (SIP based) ICF PSTN / ISDN Emulation (SIP-I based) Other Networks “Gq” interface Legacy Terminals Network Attachment Functionality NASS Resource and Admission Control Functionality RACS PSTN / ISDN GW GW “Go”interface Legacy Terminals TGW NGN Terminals MBG Customer Networks IP NGN Terminals 3GPP Terminals
IMS background (1/3) • IMS introduced in 3GPP Rel5, and further enhanced in Rel6: • IP Multimedia domain for call control based on SIP • 3GPP 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 (2/3) • IMS allows operators to have more control on the service level than with GPRS only: • Service level awareness • Correlation between the SIP application layer and the transport in PS domain • Access 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 2003 • Release 6: freezing in December 2004 • Release 7: Starting. Stage 1 requirements being currently defined
IMS background (3/3) Instant mesaging, VoIP, Games, Videotelephony, Corporate applications, ... Instant mesaging, VoIP, Games, Videotelephony, Corporate applications, ... User Ids User profile roaming security IMS Architecture Inter- Working CS/PSTN QoS policy control SIP Basic Call Control charging Service logic APIs
Legend IMS SIP: CSCF Call State Control Functions Proxy- UE Interface, Local Services Interrogating- Home Network Contact Point Serving- Session Control, Service Invocation, AS & HSS Trigger, Charging, … Signaling path Content path HSS UE #2 UE #1 IMS Registration and Call Call Flow 1 Register & find user Home 4 Register & Download IMS user Profile Register & Retrieve required S-CSCF & it’s capabilities 2 5 INVITE UE#2 into call 3 Choose correct S-CSCF 6 Upon Acceptance, Data Path is Set-up Application Servers I-CSCF 2 3 IP MULTIMEDIA SUBSYSTEM P-CSCF 4 S-CSCF 1 5 SGSN GGSN GGSN SGSN 6 UMTS PACKET DOMAIN UMTS PACKET DOMAIN
HSS I-CSCF IMS Cx Other IP/ IMS network I-CSCF Cx Mw S-CSCF Mm P-CSCF Gi UTRAN UE SGSN GGSN PS Domain IMS Architecture The HSS holds the IMS service profile of the subscribers. Control Plane Traffic Plane Go Gi • 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) 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. The PS domain provides the IP bearer to access to the IMS, i.e. a PDP context.
HSS I-CSCF IMS Cx Other IP/ IMS network I-CSCF Cx Mw S-CSCF Mm Mk P-CSCF Mr Mi MRF Mg Gq BGCF Mj MGCF Gi UTRAN SGW IMS- MGW PDF Mn Go Gi UE SGSN GGSN Legacy/ PSTN PS Domain IMS Architecture Control Plane Traffic Plane 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 Go Gi Those entities are responsible for interworking between IMS and CS domain/PSTN
NGN specific Rf Rf /Ro /Ro impacted Charging Charging Sh Sh HSS HSS Functions Functions AS AS Network Network Attachment Attachment Dh Dh Ia Ia ISC ISC Cx Cx Cx Cx Rf Rf /Ro /Ro IWF IWF Subsystem Subsystem Ib Ib Dx Dx SLF SLF IBCF IBCF Mw Mw Mw/Mk/Mm Mw/Mk/Mm Ic Ic I I - - CSCF CSCF S S - - CSCF CSCF Mw Mw If If « « Core IMS Core IMS » » Mi Mi Mi Mi SIP BGCF BGCF Mw Mw H.248 Mr Mr Mj Mj Id Id DIAMETER Mg Mg SGF SGF P P - - CSCF CSCF MGCF MGCF MRFC MRFC Ie Ie Other IP Networks Other IP Networks Gq Gq PSTN/ISDN PSTN/ISDN Mp Mp Mn Mn Gm Gm Resource and Admission Control Subsystem Resource and Admission Control Subsystem MRFP MRFP T T - - MGF MGF A A - - BGF BGF UE UE IP Transport (Access and Core) IP Transport (Access and Core) I I - - BGF BGF Core IMS use in the NGN architecture
_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 subsystem • A network attachment subsystem • A PSTN/ISDN Emulation Subsystem • Other multimedia subsystems and applications
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
IP Connectivity control • IP connectivity is provided using two control subsystems, which play a role similar to the 3GPP GPRS procedures • Network Attachment Subsystem • IP address allocation (e.g.; using DHCP). • Authentication, taking place at the IP layer • Authorisation of network access • Location management, taking place at the IP layer, • ... • Ressource and Admission Control Subsystem • Admission Control • Gate Control • ...
Emulation vs Simulation PSTN/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.
_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-I • An IMS-like functional architecture does not prevent the implementators to build a physical architecture using only softswitches (MGC) and media gateways (MGW).
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.
Z Z SIP - I H248 H248 RGW RGW or or AGW AGW DSS1/IUA S/T Z SIP - I H248 H248 RGW or AGW V5.2/V5UA AN V5.2 Z SIP - I H248 H248 RGW or AGW PSTN Z SIP - I H248 / ISUP RGW ISDN H248 or AGW TGW _Emulation typical configurations 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).
_Network Attachment Subsystem • Main functionalities • IP address allocation (e.g.; using DHCP). • Authentication and authorisation, taking place at the IP layer • Access 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 Architecture • One NASS per access network or one NASS for several access networks?
_NGN RACS description • 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 procedures • Push 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 status • Provides a Gq-like interface to TISPAN Subsystems and applications • Controls transport ressources at the boundary between the access and core networks • Using a Gate Control Protocol • May also control NAPT at core network boundaries • TISPAN has recently approved an H.248-based Gate Control Profile • An alternative COPS-based or SNMP-based standards may be pushed by some vendors at a later stage
Agenda • TISPAN_NGN Project: Steps and Requirements • TISPAN_NGN Release 1 Status: architecture outline • Why the use of IMS in NGN will help Fixed-Mobile convergence for Multimedia • Some important issues to be taken care of • Summary
Why IMS in NGN ? • IP Multimedia Substem generally fulfills the NGN requirements for conversational services • For managed, carrier operated telecom network • With 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 usage • Wider choice of IMS suppliers • Market stimulation, decreasing costs (thanks to shared development/deployment costs) • …
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
Agenda • TISPAN_NGN Project: Steps and Requirements • TISPAN_NGN Release 1 Status • Why the use of IMS in NGN will help Fixed-Mobile convergence for Multimedia • Some important issues to be taken care of • Summary
_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.
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
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
Agenda • TISPAN_NGN Project: Steps and Requirements • TISPAN_NGN Release 1 Status: architecture outline • Why the use of IMS in NGN will help Fixed-Mobile convergence for Multimedia • Some important issues to be taken care of • Conclusion
_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.
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 • UTRAN Universal Telecom. Radio Access Net.
THANKS FOR YOUR ATTENTION Questions/Comments ? ETSI TISPAN Portal: http://portal.etsi.org/Portal_Common/home.asp