Address the technical issues associated with using Voice over Internet Protocol (VoIP) phone systems to access 511 and other N11 services.
Experience from an exploration of 511 Emerging Technology Issues
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United States

511 Emerging Technology Issues: VoIP and Wi-Fi


In July 2001, the Federal Communications Commission (FCC) designated 511 as the national traveler information number, and as of 2007, twenty-eight 511 services across the country are operational. The 511 Deployment Coalition, led by the American Association of State Highway Transportation Officials (AASHTO), in close cooperation with the American Public Transit Association (APTA), the Intelligent Transportation Society of America (ITS America), and the U.S. Department of Transportation (DOT), seeks to facilitate the deployment of 511 nationally using a bottom-up approach that is guided by information sharing and a cooperative dialogue. In support of its mission, the 511 Deployment Coalition provides deployers with resources on how to develop, launch, publicize, maintain and evaluate their 511 service.

As part of this effort, the 511 Deployment Coalition has prepared the current report to explore the implications of Voice Internet Protocol (VoIP) and wireless fidelity (Wi-Fi) for 511. The report describes the problems associated with 511 VoIP call routing and provides several recommendations for how 511 deployers can address this issue in the short run, as the Deployment Coalition continues to work toward a long term solution.

Lessons Learned

VoIP, also called Internet telephony, is the technology that makes it possible to have a telephone conversation over the Internet or a dedicated (closed) IP network instead of dedicated voice transmission lines. Calls travel via IP and do not incur charges as they would over the Public Switched Telephone Network (PSTN). VoIP promises a more efficient and cost-effective replacement for traditional wireline telephony, and the market for VoIP, largely unfettered by regulation, has been growing rapidly. However, issues of security and reliability have hindered the more widespread adoption of VoIP (particularly among businesses), and in addition, the issue of N11 and other non-location specific dialing has posed a problem for VoIP service providers. Since the VoIP telephone and its associated number are not attached to a specific telephone circuit (and thus a physical address), when a user dials a short-code number, such as 9-1-1 or 511, the PSTN circuitry does not know where to route the call. Since there is no telephone circuit registered to the number, the VoIP provider routing the call is not able to use the regular look-up tables that traditional telephone carriers use to send the call to the nearest Public Safety Answering Point (PSAP). Similarly, this problem arises for Wi-Fi VoIP users, as their location is not registered, and these users are simply assigned a dynamic IP address when they log on to Wi-Fi networks.

In response to an FCC order, VoIP service providers have started to manage the call routing issue as it pertains to 9-1-1. In May 2005, the FCC released an order specifying that interconnected VoIP providers must deliver all 9-1-1 calls to the customer's local emergency operator, and that interconnected VoIP providers must provide emergency operators with the call back number and location of their customers where the emergency operator is capable of receiving it. Although the customer must provide the location information, the VoIP provider must provide the customer a means of updating this information. Following the FCC order, VoIP providers have begun to move toward a solution to this issue through "registration" of the user's physical address. For example, Vonage asks its VoIP customers to provide their physical address, so if they call 9-1-1, the call is routed to the local emergency personnel location designated for the address on file. While VoIP providers are starting to address the 9-1-1 call routing issue, progress is needed in finding a solution to the routing of 511 calls.

In an effort to move towards a solution, the 511 Deployment Coalition has developed several potential scenarios for routing 511 calls:

  • Establish a dialog with VoIP providers. Establishing a dialog is the first step in trying to coordinate a solution for 511 call routing problem. This should include a discussion of "registration" issues with VoIP service providers.
  • Investigate the option of a 511 VoIP clearing house number. Under such a scenario, VoIP providers would translate all 511 calls to a single nationwide toll free number to act as a switching point for 511 VoIP calls. From this point the caller would select to which 511 service they would like to be connected.
  • Work with VoIP providers for geo-locating VoIP callers through their IP address or some other means. This could entail enabling GPS tracking for VoIP adapters and Wi-Fi VoIP phones. Alternatively, Wi-Fi Hotspot owners could provide the physical addresses of their routers to enable geo-locating the service address (though it is unknown whether Hotspot owners would be willing to provide this information).
  • Communicate with FCC the need for this coordination of 511 and other abbreviated dialing codes (N11) services. As the FCC considers future VoIP regulations, they need to be made aware of how this issue affects 511.

Until a solution is achieved, the 511 Deployment Coalition offers the following practical recommendations to 511 deployers:

  • Publicize the "back door" number for the 511 service as an alternate method of accessing information. The only current solution is for VoIP customers to use the "back door" number of the individual 511 system. This is the 10-digit number that is translated to 511 in a particular area. While this enables VoIP customers to access 511 information, these back door numbers are different from system to system; deployers will have to market these numbers in addition to marketing "511." Deployers should post the back door number on their 511 website, and should respond to VoIP customers unable to access the 511 system directly (by providing them with the back door number).
  • Contact the VoIP service provider should problems arise. If VoIP customers complain that they have problems accessing 511 information, the deployer should make note of the carrier the caller is using and the specific problem they are having. The deployer should contact that carrier directly and notify them of the problem.

As the 511 Deployment Coalition indicated in its formal pleadings to the FCC, the 511 assignment by the FCC might be marginalized by the growth of VoIP services if action is not taken on N11 dialing. While the Deployment Coalition continues to work towards a solution to this problem, 511 deployers must also be aware of the issue and must take the steps available to them (namely, publicizing the back door number) for ensuring VoIP customers have access to 511 and thus can experience the mobility benefits of 511 traveler information.

511 Emerging Technology Issues: VoIP and Wi-Fi

511 Emerging Technology Issues: VoIP and Wi-Fi
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511 Deployment Coalition
511 Deployment Coalition

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