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2. VoIP: What really happens when I dial 911?
All corporate IP PBX systems can dial 911 services, but how much critical location data is transmitted during a life-or-death call depends on how the VoIP network and LAN are configured. Questions about IP softphones and mobile voice over Wi-Fi also complicate the issue.
Enhanced 911 service support was a major stumbling block for VoIP when it emerged in the consumer market several years ago. Technical issues, and some well-publicized incidents of failed emergency response from service providers, forced the FCC to step in with special 911 requirements for Internet phone service providers.
Many companies are still dealing with 911 issues and IP telephony deployments, as many IT departments must still manually track the location of phones in corporate offices. The easy portability of IP phones and the emergence of wireless IP handsets are challenges for maintaining an accurate device location database of phone extensions.
Enhanced 911, or E911, requires specific location information to be transmitted from a phone dialling 911 in an emergency, including building number, if a single campus address contains multiple buildings, as well as floor numbers and directional location (for example north, south, east, west).
"We do support 911 on all of our telephones on our campus," says Scott Mah, assistant vice-president for IT infrastructure at the University of Washington in Seattle. "We have policies in place to limit end-users from moving their phones around, which helps. But anytime we put a phone into service, we basically register that telephone number and its corresponding address with the database."
The database maintained by the school's IT staff is passed to local emergency 911 call centres, or public safety answering points, which link location information to each phone number in the school's system. This automatic location identification data is what's relayed to rescuers: if a 911 call is disconnected, emergency responders have information on where to go.
"[E911] is something we care a lot about and it's something we've maintained even without IP-enabled endpoints," Mah says.
There are some ways to automatically update location information when IP phones are moved. Some of this involves some planning of the campus network layout. New protocols and software are also available to help. Clever network administrators can set up pools of IP addresses into subnets which correspond to physical locations inside a building or campus. IP phones plugged into ports in these locations would automatically be linked to a building number and floor.
Cisco, Enterasys, Extreme, Nortel and Foundry all have their own proprietary discovery protocols for finding switches, routers and other devices on a network. But getting a Cisco switch to detect, let alone collect location data, on a Nortel IP phone is tricky, if not impossible.
The Link Layer Discover Protocol-Media Endpoint Discover (LLDP-MED) is a Telecommunications Industry Association standard supported by Avaya, Extreme and ProCurve by HP. LAN switches use this protocol to collect device information and location data from IP phones (as well as Wi-Fi access points) when network connections are plugged in. But because wide adoption of a standard discovery or registration protocol for phones is limited, users must work with what they have.
Technology has even emerged recently for tracking location data for IP softphone users. The software lets users input location data during the logon process for the softphone application, which is then sent if 911 is dialled from the application.
Drew Depler, IS director for Boulder County, Colo., says the proliferation of softphones and VoWi-Fi handsets is starting to emerge as another challenge for E911 services. "That really starts to become a cost-saving opportunity," Depler says of softphones, which allow county employees to work from home and cut down telecom costs.
And in the future, if they're used widely, softphones could also eliminate the need for more costly IP desktop handsets.
But, Depler says, this also raises an issue for mobile workers with softphones. "How do you track where they are? It does have some impacts on 911. There are real tenuous issues as we look at mobility and we look at IP phones moving anywhere."
Continued: How secure is VoIP?
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