911 issues with VoIP
Compiled from various sources by Erick Perez.
Introduction
I spent some time on Google looking up information about 911 and VoIP. I found several websites and I copied and pasted important points from all of them here. There is still a wealth of information out there that I have not been able to look over, so some things might be missing. Also, I do not have the meanings of several acronyms listed.
The websites I used are listed below.
Resources:
VOIP 911 issues: http://www.911dispatch.com/information/voip.html
Vonage report on 911: http://www.vonage-forum.com/printout845.html
NENA Power Point Presentation on VOIP and 911 issues: http://www.nena.org/9-1-1TechStandards/VOIP/Core%20VoIP%20&%20911%20Issues%20&%20Alternatives.ppt
Brief overview of 911 and VOIP issues: http://www.tmcnet.com/voip/1004/1004PO.htm
Vonage’s 911 service: http://www.vonage-promotion.com/911.html (Must register your VoIP line to a single address which will be a problem if you use the phone outside your home area)
Power Point presentation which includes some solutions to VoIP 911 problem: http://www.cs.columbia.edu/~hgs/papers/2004/FCC-911-2004.ppt
Nortel’s solution: http://mrtmag.com/mag/radio_nortel_proposes_voip/
Key Terms and information
Automatic Number Identification corresponds to the subscriber's seven digit telephone number. The ANI displays at the PSAP on the digital ANI display console.
ANI Failure
Failure of the end office to identify the call and provide the ANI (telephone number) to the tandem office; or, an ANI failure between the tandem office and the PSAP.
Automatic Location Identification provides for an address display of the subscriber calling 911. With ALI, the PSAP receives the ANI display and an ALI display on a screen. The ALI display includes the subscriber's address, community, state, type of service and if a business, the name of the business. The PSAP will also get a display of the associated ESN information (police, fire, rescue).
CLEC
Pronounced see-lek. Short for competitive local
exchange carrier, a telephone company that competes with an incumbent local exchange
carrier (ILEC) such as a Regional Bell Operating Company (RBOC), GTE,
ALLNET, etc.
Public Safety Answering Point, usually the police, fire and/or rescue groups as determined by the local municipalities. A "ringin" will not have ANI or ALI capabilities, but just receives calls or transferred calls from another PSAP.
Tandem Office
Telephone central office which serves as a tandem (or hub) for all 911 calls. Must be a 1AESS type of central office. The tandem office translations contain the TN/ESN relationships which route the 911 call to the proper SAP. The tandem office looks up the ANI (TN) that it receives from the end office and finds the ESN (routing information) which corresponds to a seven digit number ringing in at a PSAP.
Basic diagram and explanation of how
a 911 call is handled:
911 was designed to work with circuit switched networks.
VoIP
and 911 – Issues and solutions
This section highlights current problems with VoIP and 911 calls as well as some future benefits VoIP may offer when fully integrated with 911.
Issues
Issues with VoIP and 911:
1.
While providing some important cost-savings
to consumers, current VoIP technology does not provide for the transmission of
the caller's physical location along with the voice call. If the caller dials
911, there is no inherent protocol within the VoIP technology for routing the
call to the nearest PSAP, or to display the caller's location, telephone number
or other information.
2.
VoIP users can arrange for E911 service with their
Internet provider, and yet not pay any applicable 911 surcharges for the
service. There is anxiety among public safety agencies, county and state-level
911 agencies that E911 system funding could be reduced as more persons
convert to VoIP telephone service, and drop their wired telephone service.
3.
Several companies are already marketing
consumer-level service, including Vonage Inc. and Packet8 Inc.
Both have optional E911 dialing programs, which allow the customer to subscribe
for a monthly fee, to submit the physical location of the VoIP device, and then
to have any future 911 calls routed to the appropriate PSAP. Both of these
companies have Web sites that are quite explicit that E911 service is not
included in the basic package, the limitations on dialing 911, and that their VoIP devices
operate on AC power, making the phone unusable during a power outage.
4.
With a registered VoIP telephone, there are
hazards. If the subscriber takes the device on the road to allow long-distance
or international calling, any 911 call from the device would be routed to the
registered PSAP, back in the home region of the subscriber.
5.
VOIP calls are routed through ISPs who are routing
data and not necessarily voice packets.
Voice and data packets are handled the same, thus 911 calls do not have
any priority over any other packets being transmitted through the network.
6.
No traditional phone switches. (Conventionally PSTN [Public Switched
Telephone Network], also known as POTS [Plain Old Telephone Service], are used
to transmit analog voice data to the phone company’s central office)
7.
Area code may not reflect the actual location of the caller.
8.
If you are using a VoIP provider today, you are
likely queried for your address when subscribing (Vonage does this as an option.
Other service providers are probably doing the same). That address
is then used if you ever call 911 from that phone. There are two obvious issues
here. This could lead to you being
connected to the wrong PSAP or having emergency personnel dispatched to the
wrong location.
9.
When a VoIP 911 call is transferred to a PSAP, it
calls into the administrative lines, which are lowest priority in the center.
The fact that VoIP 911 calls are handled in a sufficiently inferior manner to
PSTN calls can eventually reduce VoIP sales if we don’t take action now! BTW,
entrenched carriers can get around this limitation but the majority of VoIP
carriers cannot.
10. Vonage
drawback: When you move, you MUST provide your new
location. You can easily update your new location through your web account. Be
aware that it can take SEVERAL DAYS before your new settings take
effect.
Future outlook on VOIP and 911:
1.
Some PSAPs are upgrading to VoIP themselves meaning
911 calls in the future could be VoIP, end-to-end. We will even be able to IM
with 911 operators. PSAPs will evolve and eventually, protocols like SIP will
make it possible to send information to the PSAP that will allow a VoIP caller
to send more information to the PSAP than a PSTN caller. As PSAPs upgrade, they
are exploring ways of getting even more information such as a schematic of a
building in the case of an alarm triggered call.
2.
One day, everyone will likely have an emergency
portal with vast amounts of medical data such as past operations, drug
allergies, current prescriptions you are taking, and more potentially life
saving information. As more and more police cruisers have wireless connectivity
and laptops, it will be possible to send vast amounts of data to the officers
en route to the 911 destination allowing them to be better prepared to handle
these emergencies.
Solutions
1.
2. Route 911 calls made over VoIP through a Softswitch which connects VoIP network to PSTN lines.
3. Nortel proposes using Location Gateway Servers (LGS) which serve as a conduit between VoIP and PSAPs. The LGS works in conjunction with a Location Information Server (LIS) which provides the LGS with a location (either an IP address or GPS coordinate [commercial GPS systems do provide a precise location – accuracy of 100 yards]). The LGS then cross references this location information with a database to determine the caller’s location. Upstart VoIP companies can rent LGS servers on a contract basis.