Internet Services for PSTN Sessions
Vijay K. Gurbani
J M van Schaick
Lucent Technologies/Bell Laboratories
Presented by: J M van Schaick
vkg@{bell-labs.com,lucent.com}
hvanschaick@lucent.com
January 14-17, 2003, Paris, France.
vkg/Jan. 2003/SIP 2003
Agenda
• The case for Internet services for PSTN
sessions.
• IETF SPIRITS WG.
• Sample services.
• Implementation status.
• Example service implementation.
• Open issues.
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Services in SIP
• It’s about services: how fast, how cheap,
how novel, how to deploy them quickly,
how to deploy them uniformly, …
• Three places to provide services:
– The core network (PSTN model)
– At the endpoints (IETF model)
– Hybrid
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The Network Today
Valuable network
Services
SCP
SCP
SS7
Long
Distance
Wireline
IN
Switches
•
•
•
•
•
•
Service Nodes/
•
Intelligent
Service
Control
Points
Prepaid
LNP, PN
Voice VPN, Free Phone
Calling Name
Call Screening
Talking Call Waiting
HLR, SMSC, …
Wireless
Peripherals
GSM
(SSP & MSC)
Wireline
INAP
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Wireless
ANSI-41
4
What’s next…?
• There are many events happening in the
PSTN (wireline, 2G, 2.5G) today – on/off
hook, call arrival, digit analysis, SMS,
registration, mobility, location update, …
• Events can be call-related, or non-call
related.
• What if we could capture these events and
transport them out to the Internet for
services?
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Basic Model
Internet
PSTN
SUBSCRIBE (or REGISTER)
200 OK
NOTIFY (or INVITE)
200 OK
MESSAGE
NOTIFY
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Need for PSTN to IP Requests
PSTN
Cloud
IP
Cloud
SIP
SIP
SIP
IN
Requests/Notifications
SPIRITS - Services in the PSTN/IN Requesting Internet Services
Key Services: Internet Call Waiting/Caller ID Delivery/Call Forwarding
http://www.ietf.org/html.charters/spirits-charter.html
http://www.bell-labs.com/mailing-lists/spirits/
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SPIRITS Events and Services (some)
•Conventional IN Events
Incoming Call Notification
(Attempt to Terminate Call)
Attempt to dial number
(specific event can be Attempt to Dial ISP Number
Dropping Dialed Connection (i.e. dropping ISP call)
ISP Connection Made
Capturing and transporting network events
•Wireless
Events
encoded
in XML
Location Update (same/another VLR
service area)
Phone On
Roaming In/Out of the Network
SMS->IM
•PSTN Events
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Voice-mail Arrival
Prepaid Zero Balance
Attempt to Forward Call
(end point could be VoIP Terminal)
Attempt to Subscribe/Unsubscribe/Provision a
PSTN Service (i.e. Set Up Call Forwarding).
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SPIRITS and PINT
• SPIRITS is closely tied to IETF PINT
(PSTN and Internet Interworking) WG, and
in fact, is a mirror image of PINT.
• PINT services: Click-to-dial, Click-to-fax,
Click-to-hear-content, …
• PINT WG concluded in February 2001,
having met its deliverables.
• Historical note: PINT was the first WG to
“extend” SIP…
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PINT and SPIRITS reference architecture
PINT/SIP
PINT Client
SPIRITS/SIP
SPIRITS Server
IP Network
PINT Server
SPIRITS
Gateway
SPIRITS/SIP
SPIRITS
Client
SSP (Switch)
INAP/SS7
Service Control
PSTN/IN
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Extending IN – Location/Presence!
Service
Control
Points
Non-IN Application
SCP
SCP
SS7
XML/SIP
IN: The Way to Get Mobile
Terminal Location
Wireless IM
Family / Fleet Tracking
Mobile Chat
Local Info
Wireless
GSM
Wireless
Switches ANSI-41
(SSP & MSC)
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Other IN-IP Service Examples
Internet Call Waiting/Caller ID
Click-to-Dial, Collaborative Surfing,
WebIVR
Calendar-based Routing
Web-Based Self Provisioning and
Preference Scripting
Mobile Chat / Fleet Tracking
Combined Voice/Data VPN
IP-Phone E.164 Hosting (ENUM)
…
Value of Converged Services:
Linking Huge Customer Base of Paying Customers
With Internet Innovation
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SMS Interoperating with IM
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• Now: SMSC node, converting to SMTP
• Proposed: SPIRITS-enabled SMSC, XMLencoding SMS text in the body of SIP message
(Proceedings of the 54th IETF, Yokohama, Japan).13
Converged services
Service Example: Mobile Tracker
Power Up
PSTN/Wireless
Notify Mobiles
Network
IN
IP
Network
SIP
Notify Online
SIP
Instant Notification to online users, when a mobile
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member of the Group Power-up or Power-down
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PSTN/IP-based Prepaid
Service
IP Network
SUBSCRIBE[balance>0]
PSTN
NOTIFY[balance>0]
SUBSCRIBE[balance<$5]
Pre-paid
Gateway
NOTIFY[balance<5]
App
Server
Rating
Server
Advantages of PSTN/IP-based
Prepaid
Low Cost of Operations
Easy to Upgrade, Manage
Customizable
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2003
Accessible to Internet Based Apps!
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Implementation Status
• Implemented SPIRITS services for wireline
switches:
– Applying presence to SIP URIs containing
telephone numbers
(sip:6302240216@lucent.com)
– Instant messaging for SIP URIs containing
telephone numbers
• Wireless services like SMS->IM are under
development
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Example service implementation
Wireline
IN
6302240216
Events: On-hook, off hook, make a call,
receive a call, …
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Example service implementation
Wireline
IN
NOTIFY
6302240216
• Coarse-grained presence
• Of course, presence based on PSTN
events does not imply availability
• But, some information is better than
having none at all!
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Open issues
• How to best provide security in an open
environment?
– Many domains:
• PSTN operator
• SIP service provider
• Internet service provider
• Privacy issues:
– Controlling event dissemination
– ACLs?
• What is the best way to deliver these services?
– Sign up on the web?
– Flyers in mail/email?
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Thank You!
mailto: hvanschaick@lucent.com
mailto: vkg@{lucent.com,bell-labs.com}
sip:vkg@www-db.research.bell-labs.com
Lucent Technologies, Inc.
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