using sip for ubiquitous and location-based communications
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Using SIP for Ubiquitous and Location-Based Communications. 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. Overview. - PowerPoint PPT PresentationTRANSCRIPT
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