I can see the value of VoIP providers proving e911 for TA based services, but how do you do e911 if you are using your Softphone via a Wi-Fi connection in a public area like a park? Unlike GPS and Cellular triangulation, these capabilities do not exist in the wi-fi world...., interested in the group's thoughts? Regards RC
It would be helpful if there was a reasonably universal Location Protocol that IP Devices could use to locate themselves. I've heard of some implementations, but none are widespread. Your VoIP Phone could ask for the nearest location information (in E-911 coordinates) from the Wi-Fi network. The location might not be very specific, but hopefully it would at least be close to the public area you were in.
Such Location Discovery Mechanisms would be helpful in many areas. Imagine your home PC being able to quickly discover your City and your browser helpfully locate certain information you are interested in. Cell phones are likely to have some of this soon, but it may be more like the cell towers feeding you the data and only that data that was paid to be broadcast. A similar advertisement system could help (or bother) motorists that have mapping products in their vehicles.
As for your Softphone, perhaps it has other location information that could help you further pinpoint your location. For instance, a device that could carry on multiple data conversations, such as a BlackBerry (phone plus PDA plus internet) could recognize that you just called an emergency number (911) and start a location discovery process on its own. In this case the BlackBerry is likely using a cell tower. However, its data terminal could ask you for further details about your location. Consider a Wi-Fi area that covers a few square blocks of a city. This extra process of asking the user to further clarify their location could be selecting two dimensions between three blocks. That data could be sent to the E-911 center via a subchannel after the conversation has started. We don't have that capability today with E-911, but perhaps the OnStar system has something like it. Cell phones can also be tracked to some degree. The Wi-Fi network of today supports connections, just as cell towers used to. Mandates required the development of location discovery mechanisms for the cell towers and back into the E-911 system. Perhaps at some point this will be added to Wi-Fi as well.