1. IP telephony @ Columbia
Prof. Henning Schulzrinne
Internet Real-Time Laboratory
Department of Computer Science
Columbia University

2. Overview Multimedia communication Multi-devices Collaboration
Audio, video, text, screen sharing, …
PSTN interworking, IVR, …
Multi-devices
IP-phone, telephone, X10, Ncast, …
Collaboration
Voic , discussion forum, …
Cinema/demo
Sep 25, 2003

3. Point to point call SIP “forking” proxy sip:wenyu@cs.columbia.edu
IP endpoint
Telephone
subscriber
Telephone
network
SIP/PSTN
gateway
SIP server
SIP “forking”
proxy
Cisco phone dials 7040 to PSTN
PSTN dials to 7141 to Grandstream phone
Cisco phone dials 7141, forks to both Grandstream and Sipc/laptop. Sipc accepts the call.
Sipc connects to another Sipc for IM, audio, video, VNC, white board, shared browsing
Cinema/demo
Sep 25, 2003

4. Multimedia conferencing
Department
PBX
SIP/PSTN
Gateway
Video encoder
Telephone
7040
IP phones
(cisco, grandstream)
sipconf
Conference server
SQL
database
Web server
Web based
configuration
Soft phones
(sipc, jsipc, messenger)
NetMeeting
H.323
siph323:
SIP-H.323
translator
PSTN dials 7149 to conference.
Sipc dials for audio/video.
Another sipc, jsipc or messenger dials for audio/video
Ncast joins the conference for video.
Cisco phone joins the conference, through auto-attendent (dial 2000).
Grandstream phone joins through auto-attendent.
Yi Qin joins using audio/video on sipc.
Cinema/demo
Sep 25, 2003

5. Non real-time collaboration
Voic
Answering machine on no-answer or busy
Auto-attendant to access Inbox
Web interface
Configuration and profile
Show leaving a voice mail on no answer and accessing using auto-attendant (need to test this?)
Show web pages configuration for contacts, user list, message board, voice mail.
Cinema/demo
Sep 25, 2003

6. Messaging and device control
X10 device
SIP
lamp
Sipc does the device control for the lamps.
DO SIP/2.0
…..
<Control>
<Action>tune AM 103K</Action>
</Control>
MESSAGE SIP/2.0
…..
turn on
Cinema/demo
Sep 25, 2003

7. Ubiquitous computing
sipd
Cinema/demo
Sep 25, 2003

8. Emergency service E-911 calls Notification Location of the caller
Audio, video, text
Notification
Cinema/demo
Sep 25, 2003

9. Summary SIP-based architecture Heterogeneous endpoints
Telephone, SIP phone, H.323
Devices like lamp, video encoder
Advanced services
Programmable call routing, voice mail, interactive voice response
Multimedia collaboration
Synchronous: conference, IM
Offline: discussion board, voic , file sharing
Cinema/demo
Sep 25, 2003