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IMS Overview. Vincente D’Ingianni Director of Professional Services Binary Systems, Inc. vincente@binary-systems.com. Contents. What is IMS? Basic Principles IMS building blocks IMS Architecture Why all the excitement? Who needs IMS Problems Conclusions. What is IMS?.
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IMS Overview Vincente D’Ingianni Director of Professional Services Binary Systems, Inc. vincente@binary-systems.com
Contents • What is IMS? • Basic Principles • IMS building blocks • IMS Architecture • Why all the excitement? • Who needs IMS • Problems • Conclusions
What is IMS? • IMS is an architecture, it is not a protocol. • Open-systems architecture that supports a range of IP-based services over both Private and Carrier networks, employing both wireless and fixed access technologies. • IMS is defined by 3GPP.
Basic Principles • Access Independence • Different Network Architectures • Terminal and user mobility • Extensive IP-based services
IMS Building Blocks • An all-IP Core Network (CN) • An all-IP Radio Access network (RAN) • Multimedia call control based on SIP • Quality of Service (QoS) support for IP
Application Layer SIP / OSA / CAMEL AS AS Control Layer Management MRF SIP, IP Provisioning HSS CSCF SG/MGCF Charging Connectivity & Access Layer MGW IP/MPLS PSTN/PLMN Number GERAN, UTRAN, WLAN, xDSL,... Mapping IMS Architecture
SGW Multimedia IP Networks Operator 1 Operator 2 BGCF CSCF HSS IM-SSF CS Domain - or - PSTN - or - Legacy - or - External BGCF OSA-SCS Applications and Services CSCF MGW MGCF SGW MRFC MRFP GGSN Alternative Access Network Mobile UE SGSN AS SCP GERAN UTRAN IMS Architecture HSS: Home Subscriber Server CSCF: Call Session Control Function: S-CSCF: Serving CSCF I-CSCF: Interrogating CSCF P-CSCF: Proxy CSCF BGCF: Breakout Gateway Control Function MGCF: Media Gateway Control Function AS: Application Server SCP: Service Control Point MGW: Media Gateway MRFC: Multimedia Resource Function Controller MRFP: Multimedia Resource Function Processor 6
Vertical vs. Horizontal Architecture Service 3 Service 2 Service 1 Service 3 Service 1 Service 2 Common functions Routing Network Network Terminal Terminal Terminal Terminal logic logic Replicated - not reusable Replication of common functions Application logic Common functions Routing
Why all of the excitement? • Imagine starting a voice call on you home phone and transferring it seamlessly to your mobile as you drive to work. • Imagine sending a multimedia message from your car that later appears on your TV screen. • Imagine watching a movie on that same TV, pausing it in mid-show and then watching it on a wireless PDA as you relax in the garden. • Imagine having a cell phone conversation with two or three friends and simultaneously sharing a video of the football match you are attending. • Imagine that all of the above can be done with a single account, on a single log-in with multiple devices over any number of access networks • These are only a few examples of seamless multimedia services that IMS will allow users to access “anywhere” at “anytime”
Who needs IMS? Fixed Network Users want • Multimedia Conferencing • Voice over IP • Streaming Services Mobile Network Users want • Push-to-X • Location Based Services • Mobile Gaming
Who needs IMS? Network Providers want • Fixed Mobile Convergence • One service - one implementation for all access types • New Business Models
An everyday scenario Mobile phone Daniel Mobile phone Vincente Mobile phone call Mobile phone call In a taxi from the airport... Walking to the office... Gerry Jacqueline
An everyday scenario Mobile phone Daniel Mobile phone Vincente Activates Video mode Views Images on his mobile In a taxi from the airport... Walking to the office... Gerry Jacqueline
An everyday scenario Mobile phone Daniel Mobile phone Vincente Buddy list > select project work group Initiate PTT session Join PTT session In a taxi from the airport... Walking to the office... Gerry Jacqueline Join PTT session Join PTT session Office PC Fixed line phone In the office... In the office...
An everyday scenario Laptop Computer Daniel Mobile phone Vincente Buddy list > personal list Invite others to Videoconference Join Videoconference At the hotel... Walking to the office... Gerry Jacqueline Join Videoconference Join Videoconference Office PC Fixed line phone In the office... In the office...
An everyday scenario Laptop Computer Daniel Mobile phone Vincente Participates in Videoconference Participates in Videoconference At the hotel... Walking to the office... Gerry Jacqueline Opens presentation and shares it with his colleagues Participates in Videoconference Office PC Fixed line phone In the office... In the office...
An everyday scenario Laptop Computer Daniel Office PC Vincente Participates in Videoconference Switches from Mobile to PC At the hotel... Arrived in the office... Gerry Jacqueline Participates in Videoconference Participates in Videoconference Office PC Fixed line phone In the office... In the office...
Problems and open issues • Architecture complexity. • Guarantees of QoS. • IETF and 3GPP standardisation co-operation. • SIP and IMS architecture are not mature enough to guarantee fully functioning network. • Terminal complexity.
There is still work to be done.... • The current work in 3GPP is still unfinished and the discussion with IETF has just been started. • The specification work still continue now.
Selected Acronyms IMS IP Multimedia Subsystem IP Internet Protocol IP-CAN IP- Connectivity Access Network ISIM IMS Subscriber Identity Module IWF Inter-Working Function LAN Local Area Network QoS Quality of Service RACS Resource and Admission Control Subsystem RAN Radio Access Network SCM Session Control Manager SGSN Serving GPRS Support Node SIP Session Initiation Protocol SLA Service Level Agreement UMTS Universal Mobile Terrestrial Access 3G Third Generation 3GPP(2) Third Generation Partnership Project (2) API Application ProgrammingInterface AS ApplicationServer BGCF Breakout Gateway Control Function CAMEL Customised Applications for Mobile Enhanced Logic CSCF Call Session Control Function BICN Bearer Independent Core Network GGSN Gateway GPRS Support Node GPRS General Packet Radio Service GSM Global System for Mobility