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Internet Real-Time Laboratory: Innovation in Networking Research

Discover the Columbia University's Internet Real-Time Laboratory, focusing on networking research with cutting-edge projects, faculty, and goals to advance internet-based collaboration applications and systems.

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Internet Real-Time Laboratory: Innovation in Networking Research

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  1. The Internet Real-Time Laboratory (IRT) http://www.cs.columbia.edu/IRT Prof. Henning Schulzrinne Dept. of Computer Science Columbia University New York, NY May 2005

  2. Networking research at Columbia University • Columbia Networking Research Center • both Electrical Engineering & Computer Science Department • 13 faculty – one of the largest networking research groups in the US • about 40 PhD students • spanning optical networks and wireless channels to operating systems, security and applications • theory (performance analysis) to systems (software, protocols) Steve Bellovin Keren Bergman Ed Coffman Predrag Jelenkovic Angelos Keromytis Aurel Lazar Nick Maxemchuk Vishal Misra Jason Nieh Dan Rubenstein Henning Schulzrinne Xiaodong Wang Yechiam Yemini

  3. Laboratory overview • Dept. of Computer Science: 33 faculty • IRT lab: • 2 post-docs, 1 researcher • 10 PhD students • includes part-time students working at IBM, Lucent, Telcordia • 7 MS GRAs • visitors (Ericsson, Fujitsu, Mitsubishi, Nokia, U. Coimbra, U. Rome, NTT, …) • China, Finland, Greece, India, Japan, Portugal, Spain, Sweden, US, Taiwan • ~15 MS and undergraduate project students

  4. Laboratory support Equipment grants and student support

  5. Overall IRT lab goals • Reliable, flexible and programmable communication infrastructure for Internet-based collaboration applications • Systematic evaluation by analysis and simulation • Demonstrate capability via prototypes • Contribute protocols to standardization • Convert prototypes into products and open-source software • Train students at all levels in current Internet research and engineering

  6. Internet telephony and multimedia CINEMA – VoIP/multimedia and collaboration system QoS measurements network application reliability performance and server architecture APIs for SIP IM and presence systems ubiquitous computing using SIP application sharing P2P SIP systems emergency services (“911”) SIP security reputation systems, spam firewalls service creation languages CPL LESS Mobile and wireless systems 802.11 handoff acceleration 802.11 VoIP performance improvements SIP-based terminal mobility personal, service and session mobility Peer-to-peer messaging  7DS Service and event discovery (GloServ) Generic signaling protocols (GIMPS) for QoS, NAT/FW, … Autonomic computing service discovery  mSLP automated server pooling  DotSlash IRT research topics

  7. IRT and standards • PI and researchers active in IETF since 1992: • RTP – lead author • RTSP – lead author • SIP – original design & core team • SIP mobility • rich presence • privacy and geo-services • SLP – extensions for scalability • GIMPS – signaling protocol

  8. Graduated PhD students • Internet telephony services, GSM interoperation (J. Lennox) • QoS and reliability measurements (W. Jiang) • Federated CDNs (L. Amini) • Pricing for QoS, LDAP performance (X. Wang) • Multicast QoS fairness & signaling (P. Mendes) • Internet telephony topics (J. Rosenberg) • Mobile peer-to-peer systems (M. Papadopouli) • Scalable resource reservation (P. Pan)

  9. Old problems and approaches: efficient codecs ubiquitous reachability audio/video synchronization network-layer mobility quality-of-service APIs and middleware New problems: controlled reachability spam cell phone ringing in lecture service availability information privacy service & personal mobility service creation by non-experts Multimedia systems problems

  10. CINEMA components Cisco 7960 MySQL sipconf rtspd user database LDAP server plug'n'sip RTSP conferencing media server server (MCU) wireless sipd 802.11b RTSP proxy/redirect server unified messaging server Pingtel sipum Nortel Cisco Meridian 2600 VoiceXML PBX server T1 T1 SIP sipvxml PhoneJack interface sipc SIP-H.323 converter sip-h323

  11. Nortel PBX Gateway PSTN Internal T1/CAS (Ext:7130-7139) External T1/CAS Call 9397134 Call 7134 Ethernet 4 5 2 1 3 5551212 Regular phone (internal) SIP server SQL database sipd sipc Bob’s phone 7134 => bob PSTN interworking

  12. SIP emergency calling GPS INVITE sips:sos@ 48° 49' N 2° 29' E outbound proxy server DHCP 48° 49' N 2° 29' E  Paris fire department

  13. SIP for ubiquitous computing • Focus on inter-domain, scalable systems • Components: • context-aware communications • context-aware service and event discovery • location-based services • global-scale event notification • service creation by end users • terminal, personal, session and service mobility

  14. Context-aware communication • context = “the interrelated conditions in which something exists or occurs” • anything known about the participants in the (potential) communication relationship • both at caller and callee:

  15. RPIDS: rich presence data • Basic IETF presence (CPIM) only gives you • contact information (SIP, tel URI) • priority • “open” or “closed” • Extend to much richer context information watcher everything PA PUA watcher "vague" PUBLISH watcher NOTIFY CPL INVITE

  16. Session mobility • Walk into office, switch from cell phone to desk phone • call transfer problem  SIP REFER • related problem: split session across end devices • e.g., wall display + desk phone + PC for collaborative application • assume devices (or stand-ins) are SIP-enabled • third-party call control

  17. Service mobility: user-adaptive device configuration “all devices that are in the building” RFC 3082? SLP 802.11 signal strength  location device controller REGISTER To: 815cepsr Contact: alice@cs PA HTTP SUBSCRIBE to each room tftp • discover room URI • REGISTER as contact for room URI SIP SUBSCRIBE to configuration for users currently in rooms room 815

  18. How to find services? • Two complementary developments: • smaller devices carried on user instead of stationary devices • devices that can be time-shared • large plasma displays • projector • hi-res cameras • echo-canceling speaker systems • wide-area network access • Need to discover services in local environment • SLP (Service Location Protocol) allows querying for services • “find all color displays with at least XGA resolution” • slp://example.com/SrvRqst?public?type=printer • SLP in multicast mode • SLP in DA mode • Need to discover services before getting to environment • “is there a camera in the meeting room?” • SLP extension: find remote DA via DNS SRV

  19. Service Location Protocol (SLP) • extended to meshed SLP (mSLP) for reliability and scaling SrvRqst SA UA SA SrvRply SrvReg DA SrvReg SrvRqst DAAdvert

  20. Location-based services • Presence-based approach: • UA publishes location to presence agent (PA) • becomes part of general user context • other users (human and machines) subscribe to context • call handling and direction • location-based anycast (“anybody in the room”) • location-based service directory • Languages for location-based services • building on experience with our XML-based service creation languages • CPL for user-location services • LESS for end system services

  21. Location-based services in CINEMA • Initial proof-of-concept implementation • Integrate devices: • lava lamp via X10 controller  set personalized light mood setting • Pingtel phone  add outgoing line to phone and register user • painful: needs to be done via HTTP POST request • stereo  change to audio CD track based on user • Sense user presence and identity: • passive infrared (PIR) occupancy sensor • magnetic swipe card • ibutton • BlueTooth equipped PDA • IR+RF badge (in progress) • RFID (in progress) • biometrics (future)

  22. Location-based IM & presence

  23. Service creation • Promise of faster service creation • traditionally, only vendors (and sometimes carriers) • learn from web models

  24. Service creation environment for CPL and LESS

  25. Ad-hoc wireless infrastructure

  26. ./: Rescue service for web servers experiencing 15 minutes of fame Extend Apache: mod_dots, dotsd, DNS, mSLP State Transition

  27. Trust paths • Problem: need to judge trustworthiness of many unknown individuals • incoming calls • incoming IM and subscription requests • Solution: trust paths for low-threshold basic trust • transitive trust with limited depth • not meant for high-value transaction • just “is person likely to be a spammer?” • use BGP-like trust vector propagation protocol • see I-D draft-ono-trust-path-discovery-00

  28. Trust paths has sent email to allows subscription from trust vector Dave trust diameter (2) Carol Alice Bob

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