1. SIP for Mobile Services Arjun Roychowdhury Hughes Software Systems

2. Internet Telephony, San Diego, 2002 Agenda Different Mobile Networks SIP in mobile networks (client and server side) SIP service models SIP and thin clients Presence & IM 3GPP update Conclusion

3. Internet Telephony, San Diego, 2002 Different Mobile Networks Remember: SIP for Mobile Networks is not ONLY SIP for 3GPP/3GPP2 ! Existing 2/ 2.5 G/CDMA 1xRTT etc. are all mobile networks that benefit from services SIP can be used to bridge all these networks together under a common service architecture wLAN another big network for SIP based mobile services (paranet !)

4. Internet Telephony, San Diego, 2002 ‘Mobility’ in SIP parlance 3 levels of mobility: –Terminal  best not handled by SIP -> typically at lower levels –Personal  handled by SIP -> registration, proxy, redirection –Service  This is where the business model lies ! Use your configured services irrespective of the device or location you are presently at. SIP helps in enabling this

5. Internet Telephony, San Diego, 2002 SIP in Mobile Networks Server Side –Provides a combination of Centralized and Peer- Peer models for service realization –Integration with Web servers (via SIP servlets, SIP CGI etc) enable new ASP based service models Client Side –Low footprint implementations ideal for Thin Client technology

6. Internet Telephony, San Diego, 2002 Why one protocol across segments ? Common Service Architecture Infrastructure Reuse Quick time to market (corollary of above point) Need is for a protocol that: –flexible to adopt to new network architectures –Not overtly complex to implement –Provides opportunities to introduce new service models SIP legacy wireless NGN wireline

7. Internet Telephony, San Diego, 2002 Vendor domain 2 Vendor domain 1 Understanding the SIP service model Application Server Controller (ASC) Application Server (AS) SIP, HTTP, RTP Service Invocation Peer - Peer Model. Each AS does a specific job. Communicating entity only interested in the result and not how

8. Internet Telephony, San Diego, 2002 Which is the right service model ? Correct Model is a mix of MS and P-P Questions to be asked: –Who makes money ? –Delays introduced by full distribution –Single Vendor/Multi Vendor Network ?

9. Internet Telephony, San Diego, 2002 Phones become PDAs PDAs become phones Phones become MP3 players … and everything goes wireless SIP for Wireless Clients SIP fits in naturally in all these devices: SIP for IP telephony SIP for Appliances (Home Network) SIP for gaming SIP for data services (IM, presence etc)...

10. Internet Telephony, San Diego, 2002 SIP and Thin Clients.. Salient Features of SIP critical for succeeding in strict boundaries of hand held devices: Simple protocol translates to simpler processing requirements A typical UE side SIP Stack can be made to be less than 50k Affinity to HTTP style makes it a natural for Web Based services Distributed service architecture allows for complete isolation of service request (on UE) and execution (on IMS nodes) j2ME is gaining lot of acceptance- when mature, backend services based on JAIN-SIP/JSLEE and SIP servelets will be key enablers of services And then there is ofcourse…..

11. Internet Telephony, San Diego, 2002 Presence & IM for Mobiles Services !! Presence+IM is the next killer app for wireless devices First lets define Presence: Its not just “online” and “offline” - often confused today with IM Presence is the dynamically changing set of means, willingness, capabilities, characteristics and ability for users to communicate and interact with each other

12. Internet Telephony, San Diego, 2002 Lightweight Stimulus Signalling Service Example - Auto Conferencing Presence Server Conferencing Server SUBSCRIBE/OK REGISTER/OK NOTIFY App. Server

13. Internet Telephony, San Diego, 2002 SIP in 3GPP update 3GPP r5 main concentration of IETF ‘IETF dependencies’ (Bundles 2, 2A, 3) RFC 3261 baselined Several ‘P-header’ drafts released http://www.3gpp.org/TB/Other/IETF.htm for details

14. Internet Telephony, San Diego, 2002 Conclusion SIP is the natural way for wireless services –adopted by 3GPP –existing 2/2.5G networks looking at SIP-enabling MSCs –Unified presence architecture in place SIP is lightweight to provide locally hosted services in handsets Wide adoption of SIP across Wireline and Wireless networks

15. Thankyou Arjun Roychowdhury aroychow@hss.hns.com Hughes Software Systems