www.convergencetechnologycenter.org DUE 402356
Vincente D’IngianniDirector of Professional ServicesBinary Systems, [email protected]
IMS Overview
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Contents
What is IMS? Basic Principles IMS building blocks IMS Architecture Why all the excitement? Who needs IMS Problems Conclusions
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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.
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Basic Principles
Access Independence
Different Network Architectures
Terminal and user mobility
Extensive IP-based services
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IMS Building Blocks
1. An all-IP Core Network (CN)
2. An all-IP Radio Access network (RAN)
3. Multimedia call control based on SIP
4. Quality of Service (QoS) support for IP
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Management
Provisioning
Charging
NumberMapping
MGW
SG/MGCF
CSCF
MRF
HSSSIP, IP
Control Layer
AS ASSIP / OSA / CAMEL
Application Layer
IP/MPLS PSTN/PLMN
GERAN, UTRAN, WLAN, xDSL,...
Connectivity & Access Layer
IMS Architecture
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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
Applications and Services
AS
SCP
Mobile
UE
GERAN
UTRAN
SGSN
IM-SSF
OSA-SCS
CSCF
HSS
SGW
Operator 1
CSCF BGCF
Operator 2
BGCF
MGCF
MRFC MRFP
GGSN
Multimedia IP
Networks
CS Domain- or -PSTN- or -
Legacy- or -
External
MGW
SGW
AlternativeAccess
Network
IMS Architecture
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Vertical vs. Horizontal Architecture
Terminal TerminalNetwork
logic
Se
rvic
e 1
Se
rvic
e 2
Se
rvic
e 3
Replicated - not reusable
Application logicCommon functions
Routing
Terminal TerminalNetwork
logic
Replication of common functions
Se
rvic
e 1
Se
rvic
e 2
Se
rvic
e 3
Routing
Common functions
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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”
Why all of the excitement?
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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
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Who needs IMS?
Network Providers want
Fixed Mobile Convergence One service - one implementation for all
access types New Business Models
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An everyday scenario
Daniel
Jacqueline
In a taxi from the airport... Walking to the office...
Mobile phone call Mobile phone call
Mobile phone Mobile phoneVincente
Gerry
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An everyday scenario
Daniel
Jacqueline
In a taxi from the airport...Walking to the office...
Activates Video mode Views Images on his mobile
Mobile phone Mobile phoneVincente
Gerry
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An everyday scenario
Vincente Daniel
Gerry Jacqueline
In a taxi from the airport... Walking to the office...
Mobile phone Mobile phone
Buddy list > select project work groupInitiate PTT session
In the office... In the office...Office PC
Join PTT session Join PTT session
Join PTT session
Fixed line phone
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An everyday scenario
Daniel
Jacqueline
At the hotel... Walking to the office...
Laptop Computer Mobile phone
Buddy list > personal listInvite others to Videoconference
In the office... In the office...Office PC Fixed line phone
Join Videoconference
Join VideoconferenceJoin Videoconference
Vincente
Gerry
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An everyday scenario
Daniel
Jacqueline
At the hotel... Walking to the office...
Laptop Computer Mobile phone
Participates in Videoconference
In the office... In the office...Office PC Fixed line phone
Participates in Videoconference
Participates in VideoconferenceOpens presentation and shares it with his colleagues
Vincente
Gerry
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An everyday scenario
Vincente Daniel
Gerry Jacqueline
At the hotel... Arrived in the office...
Laptop Computer Office PC
In the office... In the office...Office PC Fixed line phone
Switches from Mobile to PCParticipates in Videoconference
Participates in VideoconferenceParticipates in Videoconference
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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.
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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.
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Selected Acronyms
3G Third Generation
3GPP(2) Third Generation Partnership Project (2)
API Application Programming Interface
AS Application Server
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
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