1. Mobile Multimedia and VoIP Prof. Henning Schulzrinne Andrea Forte · Matthew Mintz-Habib · Takehiro Kawata · Jonathan Lennox · Anshuman Rawat · Ron Shacham · Kundan Singh · Sangho Shin · Xiaotao Wu Department of Computer Science Columbia University http://www.cs.columbia.edu/IRT CATT Research Review, December 3, 2004

2. December 3, 2004 CATT Research Review 2 Research projects Research issues in VoIP and multimedia moving from core protocols to services and mobility support PSTN emulation  new services Large-scale deployments  security, spam, management 911 for VoIP VoIP spam prevention location-based services session mobility profile mobility SIP terminal mobility TCP for streaming media rapid DHCP predictive handover L2 handoff acceleration L2 VoIP capacity enhancement applications session transport network link

3. December 3, 2004 CATT Research Review 3 Making 802.11 work for VoIP IEEE 802.11 not designed for VoIP Long layer-2 hand-off delays  cannot replace cordless phones in building Lots of related work on MAC layer –but most requires dramatic changes in APs and mobile hosts –we aim for backward-compatible changes Designed and implemented algorithms for –rapid L2 hand-off –increase capacity for VoIP calls by 25%, while reducing delay in mixed voice/data networks –decrease L3 hand-off DHCP optimizations in protocol and implementation predictive address acquisition

4. December 3, 2004 CATT Research Review 4 Re-architecting “9-1-1” for a VoIP world U.S. 9-1-1 emergency calling system is 1970’s technology – reaching end of extensibility VoIP imposes new constraints and offers new opportunities We are designing protocols and prototyping systems in cooperation with NENA (National Emergency Number Association) and MapInfo

5. December 3, 2004 CATT Research Review 5 Session and profile mobility Beyond terminal mobility Mobile devices  limited I/O capabilities –small screen –lo-res camera not suited for conferencing Utilize ubiquitous resources –video projectors –networked cameras –speaker phones Move session transparently from mobile to local (fixed) resources – and back Profile mobility: make “borrowed” devices behave as if they were the user’s –Internet pay phone –outbound call personalization –call authorization

6. December 3, 2004 CATT Research Review 6 Spam prevention in VoIP Spam & phishing likely to be a problem for VoIP –cheap –anonymous –easily automated Content-based spam filtering unlikely to work Designing spam prevention based on –user management policies –social networks Alice Bob Carol David Emily Frank has sent email to has sent IM to is this a spammer?