Using Instant Messaging and
Short Message Service for
Emergency Text Communications
Wonsang Song
Jong Yul Kim
Piotr Boni
Michael Armstrong
Henning Schulzrinne
Dept. of Computer Science
Columbia University
July 2009
Verizon
Network and Technology
Agenda
• General Overview
– Background
– Next Generation 9-1-1 (NG 9-1-1)
• Technical Overview
– Prototype Architecture
• Instant Messaging (IM)
• Short Messaging Service (SMS)
• Conclusion
Background
• Text communications is ubiquitous in the US.
– 71 million IM users in 2007
Source: comScore
– 263 million mobile telephone service subscribers
601 billion SMS messages in 2008
(SMS is up 954% from 2005)
Source: CTIA – The Wireless Association; FCC.
• But it is limited in emergency use.
– Anonymous crime tips in Boston and New York
– Text alerts on university campuses
• Text communications have advantages in emergency situation.
– When voice calls are not possible
– For speech/hearing impaired
Project goals
• Research methods to integrate IM and SMS into the NG9-1-1
architecture
• Investigate ways to maintain a “live session” with the call taker when
using IM or SMS
• Verify the approach on a working prototype
NG9-1-1 architecture
Emergency Services IP Network
(ESInet)
IP PSAP A
9-1-1
PSAP SIP
Proxy
Emergency Services
Routing Proxy (ESRP)
…
Location-to-Service
Translation (LoST)
Server
Call Takers
IP PSAP Z
PSAP SIP
Proxy
…
CallSIP-based
Origination network of IP PSAPs
Role
Network
managed by the emergency
authorities
1. Determine location
of caller
2. Route call to ESInet
3. Protocol conversion
...
ACDto ask for help
Network used by emergency caller
Examples:
PSTN, Services
VoIP, Cellular
(SMS), IM
Emergency
IP Network
(ESInet)
Call Takers
Conference
Server
ACD
Adding IM to NG9-1-1
Telematics Network
9-1-1
Emergency Services IP Network
(ESInet)
IP PSAP A
VoIP Network
PSTN Network
IM Network
PSAP SIP
Proxy
Emergency Services
Routing Proxy (ESRP)
…
Location-to-Service
Translation (LoST)
Server
Call Takers
ACD
...
IP PSAP Z
PSAP SIP
Proxy
…
SMS Network
(Cellular network)
Call Takers
Conference
Server
ACD
Adding IM to NG9-1-1 (1)
• Problem: Most IM providers use proprietary protocols.
– AOL, Yahoo!, Microsoft
• Fortunately, providers already use standard protocols
such as SIP or XMPP to interconnect IM services.
– Yahoo! and Microsoft use SIP.
– AOL and Google use XMPP.
• Prototype uses SIP MESSAGE method to add IM to
NG9-1-1.
IM client
SOS
Button
Location
Button
• SIP Communicator
– Open source, Java-based, VoIP and IM
client with SIP presence
– Multi-protocol instant messenger
• SIP, XMPP/Jabber (Google talk),
AIM/ICQ, MSN Messenger, Yahoo!
Messenger, Bonjour, IRC, RSS
– Uses JAIN SIP stack
– Based on the OSGi architecture and
using the Apache Felix implementation
SIP MESSAGE from sender’s UA
request line
header fields
message
MESSAGE urn:service:sos SIP/2.0
From: <sip:caller@verizon.com>;tag=e778529
To: <urn:service:sos>
Route: <sip:esrp.ng911.gov;lr>
Geolocation: cid:caller@verizon.com
;inserted-by="caller@verizon.com"
Content-Length: 1123
-------------------------Content-Type: text/plain
Help me..
-------------------------Content-ID: <caller@verizon.com>
Content-Type: application/pidf+xml
PIDF-LO
<presence>
<tuple id="id94954">
<status>
<gp:geopriv>
<gp:location-info>
<cl:civicAddress>
<cl:country>US</cl:country>
<cl:A1>NY</cl:A1>
<cl:A3>New York</cl:A3>
<cl:A6>Amsterdam Ave</cl:A6>
<cl:HNO>1214</cl:HNO>
<cl:PC>10027</cl:PC>
</cl:civicAddress>
</gp:location-info>
<gp:method>Manual</gp:method>
</gp:geopriv>
</status>
</tuple>
</presence>
IM message flow
LoST
Manual Entry
IP PSAP A
LLDP-MED
LoST
“Burglary!”
PSAP SIP
Proxy
Emergency Services
Routing Proxy (ESRP)
…
Location-to-Service
Translation (LoST)
Server
Location
Call Takers
ACD
...
LoST
Server
Emergency Services IP Network
(ESInet)
IM Client
SIP
IP PSAP Z
PSAP SIP
Proxy
…
SIP
SIP Proxy
Call Takers
IM Network
Conference
Server
ACD
Adding IM to NG9-1-1 (2)
• Problem: Every message from the same
‘session’ should go to the same call taker.
• Prototype keeps record of user’s address
and destination to deliver messages
consistently to one call taker.
Session-keeping mechanisms
- Associate logical
session to UI.
- Use the initial ESRP
URI while chat window is
open.
SOS
- Create soft state.
- Ignore other routing
policies such as LoST.
IP PSAP A
Location-to-Service
Translation (LoST)
Server
Emergency Services
Routing Proxy (ESRP)
- Close
ACD
Call Takers
the logical
session explicitly
when conversation
is over.
...
LoST
Server
PSAP SIP
Proxy
…
“Burglary!”
Emergency Services IP Network
(ESInet)
IM Client
IP PSAP Z
SIP Proxy
IM Network
- Create logical session
and keep using it until
call taker closes it.
Conference
Server
…
PSAP SIP
Proxy
Call Takers
ACD
Adding SMS to NG9-1-1
Telematics Network
9-1-1
Emergency Services IP Network
(ESInet)
IP PSAP A
VoIP Network
PSTN Network
IM Network
PSAP SIP
Proxy
Emergency Services
Routing Proxy (ESRP)
…
Location-to-Service
Translation (LoST)
Server
Call Takers
ACD
...
IP PSAP Z
PSAP SIP
Proxy
…
SMS Network
(Cellular network)
Call Takers
Conference
Server
ACD
Adding SMS to NG9-1-1 (1)
• Problem: Location information must be included in
emergency messages.
• Location is configured using assisted GPS on cell
phones.
– This is an example of an endpoint-centric solution.
• Location is included in the
SMS message.
26/160
To: 911
Text:
Someone in my house.
Please send help
ASAP.
[+40.9625 -73.5684]
Adding SMS to NG9-1-1 (2)
• Problem: SMS and SIP are different
protocols.
• Prototype uses SMS gateway to convert
SMS to SIP.
SMS gateway
Emergency
Service Network
Service Provider Network
Step1: extract phone number, message, and location
Step2: query LoST toWireless
resolve the ESRP URI
Network
Step3:
Location
compose
a SIP
MESSAGE request (SIP From header: sip: phone number @ IP address of the SMS gateway)
SMS Gateway
SIP Message
+ Location
Cellular
Phone SMS
PSAP
HTTP POST
+
Location
ESRP
SMS Center
SMPP
Gateway
Sybase 365
Production Server
Service Proxy
Location
ESRP
URI
LoST Server
PSAP
SMS message flow
Location
Emergency Services IP Network
(ESInet)
LoST
“Burglary!”
IP PSAP A
Cellular phone
SMS
PSAP SIP
Proxy
…
SMS
Location-to-Service
Translation (LoST)
Server
SMS GW
Emergency Services
Routing Proxy (ESRP)
Call Takers
ACD
SMPP
Gateway
...
SMSC
Sybase 365
IP PSAP Z
SIP
SIP
PSAP SIP
Proxy
LoST
…
Service Proxy
Call Takers
LoST Server
Conference
Server
ACD
Adding SMS to NG9-1-1 (3)
• Problem: Every message from the same
‘session’ should go to the same call taker.
• Prototype keeps record of the user’s phone
number and the destination URL to deliver
messages consistently to one call taker.
• Call taker has control over the session. The
session is released by the call taker.
Session-keeping mechanisms
Emergency Services IP Network
(ESInet)
“Burglary!”
Cellular phone
Location-to-Service
Translation (LoST)
Server
PSAP SIP
Proxy
…
- Create soft state
- Ignore other routing
policies such as LoST
IP PSAP A
SMS GW
Emergency Services
Routing Proxy (ESRP)
Call Takers
ACD
SMPP
Gateway
Sybase 365
PSAP SIP
Proxy
Service Proxy
- Create logical session
and keep using it until
call taker closes it.
LoST Server
Conference
Server
…
- Create soft state
- Messages from
same sender are
routed to the same
ESRP
...
SMSC
- Close the logical
session explicitly
when conversation
finishes
IP PSAP Z
Call Takers
ACD
Conclusion
• IM and SMS communications can be integrated into an IP PSAP
using SIP.
• Location can be configured and delivered with the message.
• Messages can be delivered consistently to the same call taker as if it
were a “session”.
– Mechanism within ESInet is the same for IM and SMS.
• Prototype software developed
– SIP Communicator – modified open source, Java-based VoIP/IM client
– Service Proxy a.k.a. HTTP-SIP Gateway as part of the SMS GW
functionality
– Stateful components in the emergency network
Thank you!
Backup slides…
Two approaches for location
Endpoint-centric Solution
• Location is configured by the
endpoint.
– A-GPS
• Location is inserted by the
endpoint.
– SMS application
• We are using this solution.
Network-centric Solution
• Location is configured by the
network.
– Mobile Positioning Center
(MPC)
– Position Determining
Equipment (PDE)
• Location is inserted by the
network.
– SMS Gateway
Service Proxy a.k.a. HTTP-SIP GW
• Web application running on Apache Tomcat server
– Jointly developed using Java Servlet API
• SIP client runs in parallel within the web application.
– Developed using JAIN SIP stack
• Features
– Converts from HTTP to SIP and vice versa
– Queries LoST in order to forward message to an appropriate
ESRP
– Keeps record of phone numbers and destination ESRP for a
limited time to maintain session
Wireless network message flow
Emergency
Services IP Network
Service Provider Network
Location
Verizon
Wireless Lab
Network
SMS 10 Digit Longcode used:
1093600000
10 Digit Long Code
Provisioned on SMPP GW
to point to Sybase 365
System ID
SMS Shortcode used:
10936
IP PSAP
SIP Message
+ Location
HTTP
POST
SMS +
Location
LG
Chocolate
Phone
SMS +
Location
SMS Center
SMPP
Gateway
Sybase 365 Lab
Server
Sybase 365
Production
Messaging Server
Columbia IRT Lab
Service Proxy
Location
10 Digit Long Code
Provisioned on SMSC to
Point to SMPP Gateway
HTTP client and server on Sybase 365
Server and HTTP client and server on
Service Proxy
ESRP
URI
Columbia IRT Lab
LoST Server
ESRP
Location
PSAP
URI
IP PSAP
Columbia IRT Lab
LoST Server
How can we start today?
Emergency Services IP Network
(ESInet)
…
IP PSAP
Manual Entry
LLDP-MED
FiOS ONT Box
LoST Server
PSAP SIP
Proxy
Call Taker
“Burglary!”
ESRP
ACD
LoST
Server
Today’s PSAP
IM Client
911 voice calls
…
IM-SIP/SMS-SIP
Gateway
Selective
Router
Verizon dedicated,
ALI Controller
secure IM server(s)
Telephone
Call Taker
Text Message + Location
IM Network
IM Call Taker
IM Client; preferably SIP-based
- Potential SIP conversion point
Next steps
• Propose solutions to standards organizations
• Work on sending multimedia messages (MMS) to an IP
PSAP
• Explore how commercial IM networks can be integrated
into Emergency Network
– Build or re-use an IM gateway for proprietary protocols