Support Services &
IP Multimedia Subsystem (IMS)
T-110.7111 - Internet Technologies
for Mobile Computing
Name – Koushik Annapureddy
Student Number – 84973F
Support Technologies
IP Multimedia Subsystem (IMS)
 Session Initiation Protocol (SIP)
 IP Television ( IPTV )
 Security and Trust
 Charging and Billing
Why IMS ?
 3G Networks have a Packet Switched Domain to perform data
communications.
 User can surf the content and can do anything as in the case of
ISDN,DSL.
Requirements –
 Quality of Service
 Charging
 Faster Development of Services ( Reusable Components )
IMS Architecture
IMS as a Business model
. Provides Integrated services to users. Operators want to use services
developed by third parties, combine them, integrate them with services they
already have, and provide user with completely new service
Protocols
Keeps signaling and media paths separate.
Access – independent – WLAN,ADSL,HFC,3G..
 SIP – Client – Server model (SMTP, HTTP). Can use CGI
and Java Servlets.
 AAA (Authentication, Authorization and Accounting) –
Diameter.
 COPS , RTP , RTCP
Benefits of IMS
Operators : Competitive advantages.
 Reduced time to market
 Lower deployment costs.
 Value chain control.
End Users: Services & interaction.
 Integrated rich media ( text,audio,video ) in the same
call.
 Mobile Fixed Internetworking
 Personalized communications.
SERVICES AND APPLICATIONS IN IMS
 Multi-Device Video Streaming
 IP TV
 Prioritized Presence
 Interactive Applications
 Video Conference
 Push to Talk Over Cellular (PoC)
IPTV
Today’s solutions –
 Web TV
 P2P TV
Need for IMS in IPTV solutions –
 Framework for IPTV service control, user profiles, charging (pay per
view ) , QOS.
 Convergence of IMS and TV services
 Access to TV services through different bearers ( DSL, UMTS , WLAN ,
DVB-X )
 AAA Services
IPTV Framework via IMS
Converged IPTV service
What is SIP ?
SS7 is to the mobile telephony, SIP is to the Internet.
Create , Modify and Terminate Sessions( Text, Voice, Video ).
 User location
 User capabilities
 User availability
 Call setup
 Call handling
SIP Entities
User Agents  User Agent Client ( UAC )
 User Agent Server (UAS)
Network Servers –
 Proxy Server
 Redirect Server
 Registrar
Presence, Instant Messaging and
Voice
Charging & Billing
Accounting –
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Capacity & Trend Analysis
Cost Allocation
Auditing
Charging and Billing
IMS uses the Diameter protocol to transfer the accounting information that charging in IMS
is based on.
CSCF, GGSN inform the charging system about media activity during those sessions.
IMS Event based Charging –
 Offline event based
 Online event based
Session Based Charging –
 Offline Session based
 Online Session based
Security and Trust
IMS is an overlay network on top of existing network
protocol stack, specifically IP, and uses SIP as a generic
building block.
IP – Route hijacking, denial of service, source address
spoofing.
IMS inherits the security issues of IP and SIP .
Security Threats
 Toll fraud
 Denial of Service
 Session hijacking
 Address spoofing
 Authentication and End – End Security
 Privacy
 Malware
 Energy Consumption
References
 1) Ericsson. IMS – IP Multimedia Subsystem. White Paper, October
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2004.
2) G. Camarillo and M. Garcia-Martin. The 3G IP multimedia
subsystem(IMS): merging the Internet and the cellular worlds. Wiley,
2nd edition,2006.
3) R. L. Chen, E. C. Su, V. S. Shen, and Y.-H. Wang. Introduction to
IPMultimedia Subsystem (IMS), Part 1: SOA Parlay X Web services.
IBM developerWorks, September 2006.
4) Kuhn, R.: Security considerations for voice over IP systems.
5) IP Multimedia Subsystem (IMS); stage 2. 3GPP TS 23.228, Release 7
2006.
6) H. Schulzrinne, G. Camarillo, A.R. Johnston, J.Peterson, R. Sparks,
M. Handley and E. Schooler. SIP: Session Initiation Protocol. IETF RFC
3261, June2002.
Thank you
Any questions