Thinking About 911 in a Converged World


One of the strongest trends we’ve seen in our research around communications and collaboration is the desire by both IT and end-users to embrace mobility. IT shops are evaluating the potential to reduce infrastructure costs such as desktop phones, and power over Ethernet, (and all the cooling/power resiliency issues that come with PoE), by moving to software-based phones. Meanwhile, an increasingly mobile workforce looks to shun the archaic desktop phone in favor of software-based telephony and/or UC, or their mobile phones. “Why can’t I just use my iPhone?” is a common refrain we hear from our clients when they speak of requests from the workers they support.

Meanwhile, many companies have invested significant resources in building out infrastructure to support user location tracking for calls made to 911. A large number of our clients, as a result of legal requirements, the desire to avoid lawsuits, or simply because they feel that it is the right thing to do, have deployed technologies such as PS/ALI (Private Switch/Automatic Location Identification) and ELIN (Emergency Location Identification Number) capabilities to provide local emergency centers with detailed location information; not just building addresses but more specific information such as floors, wings, or cubicles. Each of these approaches is based on maintaining a database of user locations typically by associating their hard phone with a known location. Most approaches require some sort of manual setup to populate databases. In the VOIP world most telephony vendors support automated location tracking based on IP address or by an Ethernet switch identifying a phone plugged into a port and mapping the phone to a user’s location.

Softphones and cellular phones change the game. A softphone can make calls from anywhere--desktop, conference room, shared workspace, cafeteria, home, or public hotspot. Tracking a softphone user’s location presents two challenges: Identifying that their location has changed, and updating location mapping databases with the current location. Fortunately solutions exist for just about all softphone products, either delivered by the softphone vendor, or via partnership with 911 solutions vendors such as 9-1-1 Enable, 911 ETC, or RedSky. Solutions are based on the softphone, or a shim application recognizing a location change by looking at items such as the IP address or MAC address of the Ethernet or WLAN connection, and then asking the user to validate or enter their current address. A “Master Address List” service can provide a drop-down box with pre-populated known user locations to reduce errors from manual entry. Once the user updates their address, the client then updates the appropriate location-mapping database.

While these solutions solve part of the problem, they still present challenges. Changes to location mapping databases can take time to propagate to emergency services authorities. And the enterprise may lack connectivity to a remote PSAP (public safety answering point). For example, what happens if someone on travel in Omaha makes a 911 call via their softphone to a PBX in New Jersey? Here the solution is PSAP forwarding services that intercept the 911 call, look up the current user location information, and forwards the call to the correct PSAP. Service providers such as Intrado and Dash (now part of provide this back-end service through the 911 solutions vendors previously mentioned.

Great, so now we’ve solved the problem of softphones; what about cellular users? Here the challenges are a bit more problematic. When a cell user calls 911 they transmit both their own phone number (known as an ANI or Automatic Number Identification) and the location of the cell tower where they are connected. Over time, additional capabilities such as location derived from GPS or cell tower triangulation will give authorities a better grasp of location. But even with these additional functions there are still problems. As Mark Fletcher, ENP, Avaya’s 911 guru, recently said to me, “phone GPS can’t track altitude.” Meaning that even if PSAPs can pinpoint the location of a cell phone on a map, they can’t tell what floor you are on.

Longer term the NENA (the National Emergency Number Association) has proposed a new approach for 911 that eliminates the need for cumbersome database management and provides greater location awareness information to PSAPs, but providers have yet to adopt NG 9-1-1 capabilities, so cell phone tracking remains problematic. Alternatively, enterprises could potentially deploy cell phone clients such as Avaya oneX mobile or Cisco Jabber and use the WLAN to track location, but this approach only works when inside of corporate offices and attached to the enterprise WLAN.

The bottom line: softphone support in accordance with typical 911 location mapping requirements is possible, though it may require investment in third-party 911 management platforms and PSAP call routing services. Cell phone tracking is still problematic.

Copyright © 2011 IDG Communications, Inc.

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