1. Emergency Calling Architecture
Henning Schulzrinne
Dept. of Computer Science
Columbia University
September 2005
VON Boston

2. Overall pieces needed Obtain civic and/or geo location
End system must obtain emergency dial sequences
911, regional variations
possibly for multiple different services
Map location to PSAP(s)
Identify call as an emergency call
Mid-call behavior
call-backs, caller-initiated BYE, call transfer at PSAP, location updates, …
September 2005
VON Boston

3. Stages I1 I2 I3 spec. available? use 10-digit admin. number? mobility
callback
number to PSAP?
caller
location to PSAP?
PSAP
modification
ALI (DB)
new services I1
now
allowed
stationary no
none I2
June 2005
nomadic
yes
no (8 or 10 digit)
update I3
2005
mobile
IP-enabled
ALI not needed
MSAG replaced by DNS
location in-band
GNP
multimedia
international calls
September 2005
VON Boston

4. Architecture DHCP DHCP September 2005 VON Boston VSP ISP SIP config
PSAPs
outbound
proxy
DHCP
home
September 2005
VON Boston

5. Mapping architecture carrier X customers R R R R R R flooding nj.us
knows all
trees;
caches results R R R R R R
flooding
nj.us
ny.us
bergen.nj.us
leonia.bergen.nj.us
September 2005
VON Boston