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The Internet Real-Time Laboratory

The Internet Real-Time Laboratory. Henning Schulzrinne April 2002 http://www.cs.columbia.edu/IRT. Networking research at Columbia University. Columbia Networking Research Center spans EE + CS 15 faculty – one of the largest networking research groups in the US about 40 PhDs

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The Internet Real-Time Laboratory

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  1. The Internet Real-Time Laboratory Henning Schulzrinne April 2002 http://www.cs.columbia.edu/IRT

  2. Networking research at Columbia University • Columbia Networking Research Center • spans EE + CS • 15 faculty – one of the largest networking research groups in the US • about 40 PhDs • spanning optical networks to operating systems and applications • theory (performance analysis) to systems (software, protocols)

  3. Laboratory overview • Dept. of Computer Science: 30 faculty • IRT lab: 12 PhD students • 4 at IBM, Juniper, Lucent, Telcordia • 5 MS GRAs • 5 visitors (Ericsson, Fujitsu, Mitsubishi, Nokia, U. Coimbra) • 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. IRT topics • Internet multimedia protocols and systems • Internet telephony and radio (J. Lennox, X. Wu, K. Singh, K. Arabshian, W. Jiang, J. Rosenberg, A. Dutta, K. Koguchi; K. Butler, A. Nambi, S. Narayanan, A. Khwaja, S. Sridhar) • Content distribution networks (L. Amini, Y. Nomura) • Internet event distribution (P. Koskelainen) • Wireless ad-hoc networks (M. Papadopouli, S. Sidiroglou)

  6. IRT topics • Quality of service • Pricing for adaptive services (RNAP) (X. Wang) • Scalable resource reservation protocols (P. Pan) • BGRP for aggregation, YESSIR for applications • Fair multicast resource allocation (P. Mendes)

  7. IP telephony: QoS estimation • QoS estimation of voice traffic • influence of loss correlation + FEC • estimation via objective methods • automated MOS estimation via speech recognition • Planning: tools for automated end-to-end assessment

  8. CINEMA • Web interface • Administration • User configuration • Unified Messaging • Notify by email • rtsp or http • Portal Mode • 3rd party IpTelSP

  9. 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

  10. CINEMA • Goal: fully integrated communications platform: • synchronous + asynchronous collaboration • calendaring • multimedia collaboration: G.711 and high-quality audio, video, shared whiteboard, chat, shared applications • Web control or VoiceXML interaction • support pure VoIP and hybrids

  11. Internet telephony: sipc • Cross-platform tool for integrated multimedia communications • Windows 98/NT/2K/XP • Solaris, Linux, FreeBSD • Support media plug-ins • Screen sharing • IM and presence • programmable logic (cgi, CPL) • Device control (electric appliances) • (Emergency) notification • Conference control (in progress)

  12. 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

  13. Internet telephony: emergency communications • 911 services architecture • emergency notification EPAD 302 Moved Contact: sip:sos@psap.leonia.nj.us Contact: tel:+1-201-911-1234 REGISTER sip:sos Location: 07605 SIP proxy INVITE sip:sos Location: 07605

  14. Languages for service creation • Traditionally, telecom services created by switch vendors • Web model: allow users and organizations to create custom services • Two models: sip-cgi and CPL • Sip-cgi: cgi scripts for call handling logic

  15. Internet telephony: APIs • APIs for IM and presence (JAIN JSR) • design and implementation • cooperation with Panasonic

  16. Call Processing Language • XML-based language <incoming> <address-switch field="origin" subfield="host"> <address subdomain-of="example.com"> <location url="sip:jones@example.com"> <proxy> <busy> <sub ref="voicemail" /> </busy> <noanswer> <sub ref="voicemail" /> </noanswer> <failure> <sub ref="voicemail" /> </failure> </proxy> </location> </address> <otherwise> <sub ref="voicemail" /> </otherwise> </address-switch> </incoming>

  17. Mobile ad-hoc networks: 7DS • Wireless infrastructure slow to emerge (Metricom , 3G $$$) • 802.11b cheap and simple to deploy • Mobile devices spread data in densely populated areas (e.g., NYC)

  18. 7DS • Content-independent: works for any web object • Uses standard caching mechanism • After 25’, 90% of interested users have data (25 hosts/ ) • Also, data upload:

  19. Ad-hoc wireless infrastructure

  20. 7DS research issues • Effects of power conservation, collaboration mechanism, wireless coverage range, density of devices on information dissemination • e.g., how fast does information spread in such setting ? what is the average delay that a host experience until it gets the data ? • Performance analysis via simulations and diffusion controlled processes theory

  21. Fairness for multicast Differentiated Service (DiffServ) networks divide traffic into different service quality levels, considering their quality requirements: • Intolerant (loss&delay) applications will use DiffServ Premium services, while tolerant applications can use Assured services; • Multimedia flows multicast to heterogeneous receivers will use Assured services; • Problem: Resources aren’t fairly distributed between flows inside a DiffServ service.

  22. Multi-receiver fair allocation Provide fair distribution of Assured services resources between multimedia multicast flows considering: • The number of receivers in each multicast flow; • A maximal utilization of resources; • Differential dropping between flows that overpass their share of service resources; • A Multi-Receiver Utilization Maximal fair mechanism (MRUM) is being developed.

  23. Cost U1 U2 U3 Budget Bandwidth Quality of service: pricing • Bandwidth: decrease of marginal returns adaptive services

  24. Bandwidth pricing • Congestion pricing • See GWB, turnpike, electricity • Higher overall utility • Prices constant for periods O(min) • Auction or tatonnement pricing • Charge for usage and reservation

  25. Service location • Enhancements to Service Location Protocol (SLP): • reliability and scaling (meshed SLP) • remote discovery • attributes

  26. Summary and future plans • Personal and session mobility • Service creation for VoIP • Integrating the natural environment into IP communications • Conferencing and conference control • Ad-hoc and hybrid ad-hoc/infrastructure networks • Emergency communications • Network reliability

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