IP Multimedia Subsystem

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• IP Multimedia Subsystem
• S?t???? ??µ?t???d??

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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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What is the IMS?

• IMS is an architecture, it is not a protocol
• Open-systems architecture that supports a range
  of IP-based services over both PS and CS
  networks, employing both wireless and fixed
  access technologies
• IMS is defined by 3GPP

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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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Basic Principles

• Access Independence
• Different Network Architectures
• Terminal and user mobility
• Extensive IP-based services

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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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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

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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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IMS Architecture(1)
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IMS architecture(2)
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
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Vertical vs. Horizontal Architecture
Service 3
Service 2
Service 1
Service 2
Service 3
Service 1
Common functions
Routing
Network
Network
Terminal
Terminal
Terminal
Terminal
logic
logic
Replicated - not reusable
Replication of common functions
Application logic
Common functions
Routing
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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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Why all 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

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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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Who needs IMS...(1)

• Fixed Network Users look for....
• Multimedia Conferencing
• Voice over IP
• Streaming Services
• Mobile Network Users look for....
• Push-to-X
• Location Based Services
• Mobile Gaming

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Who needs IMS...(2)

• Network Providers look for....
• Fixed Mobile Convergence
• One service - one implementation for all access
  types
• New Business Models

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An everyday scenario
Yiannis
Mobile phone
Mobile phone
Nicos
Mobile phone call
Mobile phone call
In a taxi from the airport...
Walking to the office...
Stelios
Andri
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An everyday scenario
Mobile phone
Yiannis
Mobile phone
Nicos
Activates Video mode
Views Images on his mobile
In a taxi from the airport...
Walking to the office...
Stelios
Andri
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An everyday scenario
Mobile phone
Nicos
Yiannis
Mobile phone
Buddy list gt select project work group Initiate
PTT session
Join PTT session
In a taxi from the airport...
Walking to the office...
Stelios
Andri
Join PTT session
Join PTT session
Office PC
Fixed line phone
In the office...
In the office...
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An everyday scenario
Laptop Computer
Yiannis
Mobile phone
Nicos
Buddy list gt personal list Invite others to
Videoconference
Join Videoconference
At the hotel...
Walking to the office...
Stelios
Andri
Join Videoconference
Join Videoconference
Office PC
Fixed line phone
In the office...
In the office...
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An everyday scenario
Laptop Computer
Yiannis
Mobile phone
Nicos
Participates in Videoconference
Participates in Videoconference
At the hotel...
Walking to the office...
Stelios
Andri
Participates in Videoconference
Opens presentation and shares it with his
colleagues
Office PC
Fixed line phone
In the office...
In the office...
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An everyday scenario
Laptop Computer
Nicos
Yiannis
Office PC
Participates in Videoconference
Switches from Mobile to PC
At the hotel...
Arrived in the office...
Stelios
Andri
Participates in Videoconference
Participates in Videoconference
Office PC
Fixed line phone
In the office...
In the office...
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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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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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Contents

• What is the IMS
• Basic Principles
• IMS building blocks
• IMS Architecture
• Why all the excitement
• Who needs IMS
• Problems
• Conclusions

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Conclusion (1)

• Mobility and the Internet converge in the design
  and implementation of the mobile core network

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Conclusion (2)

• 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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THANK YOU

• Questions/Comments ?

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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 Universa
l Mobile Terrestrial Access
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Bibliography

• IP Multimedia Subsystem (IMS)-G.Xylomenos and
  V.Vogkas
• The value of using the IMS architecture,WHITE
  PAPER, ERICSSON
• 3GPP TS 23.228 Technical Specifications and Group
• Have Solution, Will Deliver http//www.lucent.com/
  news_events/articles/020705.html
• IMS in Converged Networks http//www.newport-netwo
  rks.com/solutions/converged.html
• Wireless Multimedia in 3G Networks G.Xylomenos
  and V.Vogkas