Using SIP for Ubiquitous and Using SIP for Ubiquitous and Location-Based Location-Based

CommunicationsCommunications

Henning Schulzrinne(with Stefan Berger, Jonathan Lennox, Maria

Papadopouli, Stelios Sidiroglou, Kundan Singh, Xiaotao Wu, Weibin Zhao)

Columbia University IRT Lab CUCS Site Visit

January 2003

OverviewOverview

What is ubiquitous computing? What is SIP? Location-based computing in SIP On-going work

Ubiquitous/pervasive Ubiquitous/pervasive computingcomputing Computers embedded into the

environment Mobility, but not just cell phones Computation and communications Integration of devices

“borrow” capabilities found in the environment composition into logical devices

seamless mobility session mobility adaptation to local capabilities environment senses instead of explicit user

interaction from small dumb devices to PCs

What are the core What are the core problems?problems?

Interested in multimedia communications ( Jason Nieh for computational mobility)

Moving and splitting sessions Locating services Event notification

What is SIP?What is SIP? Session Initiation Protocol

protocol that establishes, manages (multimedia) sessions also used for IM, presence & event

notification Developed at Columbia (with others) Standardized by IETF, 3GPP (for 3G

wireless), PacketCable About 60 companies produce SIP

products Microsoft’s Windows Messenger

(4.7) includes SIP

Session mobilitySession mobility Walk into office,

switch from cell phone to desk phone e.g., wall display

+ desk phone + PC for collaborative application

SIP third-party call control

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 Need to discover services in local

environment SLP (Service Location Protocol) allows

querying for services “find all color displays with at least XGA

resolution” CU SLP extensions for scalable, resilient

discovery Need to discover services before

getting to environment “is there a camera in the meeting

room?” CU SLP extension: find remote DA via

DNS SRV

Determining locationsDetermining locations For many devices,

can’t afford hardware to determine location Implementing

BlueTooth-based location sensor networks

CU 7DS project: offer local content + location

Developing programmable active badges with IR and RF capabilities

Location-based servicesLocation-based services

CPL-basedruleset

“Alice has enteredRoom 700”

Make this Alice’sphone

“WNYC”

SIP-basedevent notification

SIP-basedmessaging

Location filtering languageLocation filtering language

location-filteringlanguage

“within 30’ of campus”

“EST”

40.8N, 73.9W

in train only IMcommunication filtering

geocivilcategoricalproperties

Columbia SIP servers Columbia SIP servers (CINEMA)(CINEMA)

InternalTelephoneExtn: 7040

SIP/PSTN Gateway

Department PBX

Web based configuration

Web server

Telephoneswitch

SQLdatabase

sipd:Proxy, redirect, registrar server

Extn: 7134

xiaotaow@cs NetMeeting

H.323

rtspd: media server

sipum: Unified messaging

Quicktime

RTSP clients

RTSP

Extn: 7136

713x

Single machine

SNMP(Network Management)

sipconf: Conference server

siph323: SIP-H.323 translator

Local/long distance1-212-5551212

Pushing context-sensitive Pushing context-sensitive data to usersdata to users

User with mobile device should get location information when entering city, campus or building

flight and gate information maps and directions local weather forecast special advisories (“choose security

checkpoint 2”) Often does not require knowing user

but interface with (e.g.) calendar Example Columbia implementation (7DS):

OBEX data exchange over BlueTooth PDA pushes current appointment or event

name base station delivers directions and map

ConclusionConclusion SIP + auxiliary protocols supports many

of the core requirements for ubiquitous computing and communications: mobility modalities: terminal, user, session,

service service negotiation for devices with different

capabilities automatic configuration and discovery event notification and triggered actions automatic actions: event filtering, CPL, LESS SIP offers a loosely-coupled approach

Also need data push functionality