The Internet Real-Time Laboratory (IRT) Prof. Henning Schulzrinne Dept. of Computer Science Columbia University New York,

The Internet Real-Time The Internet Real-Time Laboratory (IRT)Laboratory (IRT)

http://www.cs.columbia.edu/IRTProf. Henning Schulzrinne

Dept. of Computer ScienceColumbia University

New York, NYJune 2004

Networking research at Networking research at Columbia UniversityColumbia University Columbia Networking Research

Center spans Electrical Engineering &

Computer Science Department 15 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)

Keren Bergman

Andrew Campbell

Ed Coffman

Predrag Jelenkovic

Angelos Keromytis

Aurel Lazar

Nick Maxemchuk

Vishal Misra

Jason Nieh

Dan Rubenstein

Henning Schulzrinne

Xiaodong Wang

Yechiam Yemini

Laboratory overviewLaboratory overview Dept. of Computer Science: 33 faculty IRT lab:

1 post-doc 12 PhD students includes 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 supportLaboratory support

Equipment grants and student support

Overall IRT lab goalsOverall 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

IRT research topicsIRT research topics Internet telephony and

multimedia CINEMA – VoIP/multimedia

and collaboration system QoS measurements network application

reliability APIs for SIP IM and

presence systems ubiquitous computing

using SIP emergency services

(“911”) SIP security

non-PKI-based assertions service creation

languages CPL LESS

Mobile and wireless systems

802.11 handoff acceleration

802.11 VoIP performance improvements

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

Graduated PhD studentsGraduated 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)

Multimedia systems Multimedia systems problemsproblems 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

CINEMA componentsCINEMA components

RTSP

sipum

Cisco 7960

sipvxmlSIP

rtspdsipconfLDAP server

MySQL

PhoneJack interface

sipc

T1T1

sipd

mediaserver

RTSP

SIP-H.323converter

messagingserver

unified

server(MCU)

user database

conferencing

sip-h323

VoiceXMLserver

proxy/redirect server

Cisco2600

Pingtel

wireless802.11b

PBX

MeridianNortel

plug'n'sip

PSTN interworkingPSTN interworkingNortel PBXPSTN

External T1/CAS

Regular phone(internal)

Call 93971341

SIP server

sipd

Ethernet

3

SQLdatabase

4 7134 => bob

sipc

5

Bob’s phone

GatewayInternal T1/CAS(Ext:7130-7139)

Call 71342

5551212

SIP emergency callingSIP emergency calling

GPS

48° 49' N 2° 29' E

INVITE sips:sos@

DHCP

outboundproxy server

48° 49' N 2° 29' E Paris fire department

SIP for ubiquitous SIP for ubiquitous computingcomputing 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

Context-aware Context-aware communicationcommunication

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:

time CPL

capabilities caller preferences

location location-based call routinglocation events

activity/availability “rich” presence

sensor data (mood, bio)

not yet, but similar in many aspects to location data

RPIDS: rich presence dataRPIDS: 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

PA

watcher

PUA watcher

watcher

PUBLISH

NOTIFY

everything

"vague"

CPL

INVITE

Session mobilitySession 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

PA

devicecontroller

SUBSCRIBEto each room

SUBSCRIBE to configurationfor users currently in rooms

1. discover room URI2. REGISTER as contact for room URI

tftp

HTTP

Service mobility: user-Service mobility: user-adaptive device adaptive device configurationconfiguration

SLP

“all devices that are in the building”RFC 3082?

802.11 signal strength

location

REGISTERTo: 815cepsrContact: alice@cs

SIP

room 815

How to find services?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

Service Location Protocol Service Location Protocol (SLP)(SLP) extended to meshed SLP (mSLP) for

reliability and scaling

UA

DA

SA

SA

SrvReg

SrvRply

SrvRqst

SrvRqst SrvReg

DAAdvert

Location-based servicesLocation-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

Location-based services in Location-based services in CINEMACINEMA 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)

Location-based IM & Location-based IM & presencepresence

Service creationService creation

programmer, carrier

end user

network servers

SIP servlets, sip-cgi

CPL

end system VoiceXML VoiceXML (voice),LESS

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

Service creation environment Service creation environment for CPL and LESSfor CPL and LESS

Ad-hoc wireless Ad-hoc wireless infrastructureinfrastructure

./: Rescue service for web ./: Rescue service for web servers experiencing 15 minutes servers experiencing 15 minutes of fameof fameExtend Apache: mod_dots, dotsd, DNS, mSLP

State Transition