The Internet Real-Time Laboratory Henning Schulzrinne September 2003

The Internet Real-Time Laboratory Henning Schulzrinne September 2003 http: //www. cs. columbia. edu/IRT

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

Laboratory overview n n Dept. of Computer Science: 32 faculty IRT lab: 13 Ph. D students n n n includes 3 part-time students working at IBM, Lucent, Telcordia 2 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

Laboratory support Equipment grants and student support

IRT topics n Internet multimedia protocols and systems n n Internet telephony and radio (J. Lennox, X. Wu, K. Singh, 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, K. Arabshian) Wireless ad-hoc networks (M. Papadopouli, S. Sidiroglou)

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

IP telephony: Qo. S estimation n Qo. S estimation of voice traffic n n influence of loss correlation + FEC estimation via objective methods automated MOS estimation via speech recognition Planning: tools for automated end-toend assessment

CINEMA n Web interface n n Administration User configuration Unified Messaging n Notify by email n rtsp or http Portal Mode n 3 rd party Ip. Tel. SP

CINEMA components Cisco 7960 My. SQL sipconf user database LDAP server conferencing server (MCU) sipd proxy/redirect server rtspd RTSP media server RTSP unified messaging server Pingtel Nortel Meridian PBX T 1 sipum Cisco 2600 T 1 Voice. XML server SIP sipvxml Phone. Jack interface sipc SIP-H. 323 converter sip-h 323 plug'n'sip wireless 802. 11 b

CINEMA n Goal: fully integrated communications platform: n n n synchronous + asynchronous collaboration calendaring multimedia collaboration: G. 711 and highquality audio, video, shared whiteboard, chat, shared applications Web control or Voice. XML interaction support pure Vo. IP and hybrids

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

PSTN interworking PSTN External T 1/CAS 1 Call 9397134 Nortel PBX Internal T 1/CAS (Ext: 7130 -7139) 2 Gateway Call 7134 Ethernet 5551212 Regular phone (internal) 5 3 SIP server sipc Bob’s phone SQL database sipd 4 7134 => bob

Internet telephony: emergency communications n n 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 INVITE sip: sos Location: 07605 SIP proxy

Languages for service creation n n 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

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

Call Processing Language n 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>

Mobile ad-hoc networks: 7 DS n n n Wireless infrastructure slow to emerge (Metricom , 3 G $$$) 802. 11 b cheap and simple to deploy Mobile devices spread data in densely populated areas (e. g. , NYC)

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

Ad-hoc wireless infrastructure

7 DS research issues n Effects of power conservation, collaboration mechanism, wireless coverage range, density of devices on information dissemination n n 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

Dotslash – A Web Hotspot Rescue System n Web Hotspot n n n A sudden, dramatic surge of request rate Short-term overload: long delay or no service Challenges n n n Hard to predict Build up quickly Large magnitude

Dotslash n Motivation n One site can dramatically vary in request rate insufficient capacity A group of sites peak at different time, spared capacity at some sites Rescue service n n Dynamic collaboration among different sites Enable a site to expand its capacity dynamically and quickly

Functional Components n n n Workload monitoring Discovery of spare capacity at other sites Request distribution and redirection Dynamic virtual hosting Dynamic replication of content Rescue relationship management

Basic Architecture Extend Apache: mod_dots, dotsd, DNS, m. SLP State Transition

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

Multi-receiver fair allocation Provide fair distribution of Assured services resources between multimedia multicast flows considering: n n 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.

Quality of service: pricing n Bandwidth: decrease of marginal returns adaptive services U 1 U 2 U 3 Cost Budget Bandwidth

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

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

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