Emergency 911 services challenge today's IP networks

Secure, intelligent cabling systems help to meet the emerging need.

Secure, intelligent cabling systems help to meet the emerging need.

In the late 1950s, the National Association of Fire Chiefs recommended that a single number be allocated to report fires. It took 10 years for AT&T to designate the three-digit number 9-1-1 as the "universal emergency number" for citizens throughout the United States. 911 serves as a nationwide telephone number that provides the public with direct access to a public safety answering point (PSAP). A PSAP is an agency or facility designated and authorized to receive and respond to emergency calls requiring one or more public services, such as police, fire, and/or ambulance services.

Enhanced 911

At the same time nationwide adoption of 911 was being encouraged, telecommunications technologies were developing. The 1990s saw the advent of the Internet age and mobile communications, trends that introduced an entirely new set of challenges for 911 services. In 1996, the Federal Communications Commission (FCC) established Enhanced 911 (E911) to improve the effectiveness and reliability of wireless and mobile 911. Its aim is to provide dispatchers with additional information and improve the accuracy of finding the caller's geographical position.

When a person dials 911 using a traditional wireline phone, the call is routed to the nearest PSAP that then distributes the emergency call to the proper service. But when a mobile-phone user dials 911, the call may not be routed to the closest 911 center, and the call taker does not receive the callback phone number or the location of the caller. This is especially important when the caller is disoriented, disabled, unable to speak, or does not know their location.

Phase I of E911 legislation, implemented in 1998, requires carriers, upon request of the local PSAP, to report the telephone number of a mobile 911 caller and the location of the antenna that received the call. Phase II—which has an implementation timeline of October 2001 to December 2005—requires mobile carriers to provide the precise location of a wireless 911 caller within 50 to 100 meters.

More recently, the FCC has considered and addressed E911 obligations of additional telecommunications services, such as multi-line telephone systems (MLTS) that allow multi-line businesses and multi-tenant buildings to eliminate the need for an external line for each telephone within their operation by using private branch exchanges (PBXs). Traditional PBX is a proprietary telephone-switching system that resides within an enterprise network and connects internal telephone extensions to each other and to the public switched telephone network. This lets business and multi-tenant residential building owners provide more-efficient service using fewer lines. Office buildings, hospitals, universities, and hotels are examples of organizations that share few outside lines.

E911 sets a series of demands that let the telephone company connect the number from which the call was placed to a database of current location information. The database provides the physical location or the automatic location information (ALI) of the caller's telephone number in addition to the billing address.

With an enterprise PBX, however, the street address alone does not ensure specific location information. A call placed from a particular room in a multi-story building, for example, may not be uniquely identified with seven-digit numbers and recognized by the telephone company. So, in an emergency situation, the 911 response team has a particularly hard time locating the caller. For a timely response, emergency personnel need to know specifics—Building 5, west wing, 15th floor, office number 312.

IP advances

Complicating matters, many enterprises have adopted a converged voice/data network over Internet Protocol (IP). IP-PBX delivers PBX-like services to IP phones, but over IP-based LANS or WANs rather than over circuit-switched networks as in traditional PBX systems.

IP's advantages are astounding. PBXs supporting VoIP serve as a gateway and avoid tolls by offloading outgoing voice calls from the public network to the IP network. In traditional PBX phone systems, the phone outlet is wired to a specific PBX port, which dictates the phone number. If a user wants to move to a different location within an organization while retaining the same telephone extension, changes have to take place through rewiring (moves, adds, and changes—MACs), or at the software level. The information has to be updated at the extension map to correlate the extension number with the physical location (room or office number).

With IP telephony, however, the phone number will follow the user, and the phone will work from any outlet in the building. Employees can move themselves and their extension number from room to room without the complicated changes required of the traditional PBX.

While the VoIP gateway has eased mobility and allowed businesses to save costs on interoffice toll calls, questions arise. For example, what happens when a 911 call is placed from an IP device? And, to which response center does the call go?

The FCC and national emergency authorities have started tackling this issue, but they are only in the early stages. In the meantime, the number of enterprises implementing IP-based systems continues to grow. A study by Gartner Research (www.gartner.com) predicts that IP-capable phone systems will constitute nearly 97% of the market by 2007 at a value of $4.2 billion, up from 56% last year. The study also says that IP-ready PBX shipments presently exceed those of traditional time-division multiplexing (TDM)-based PBXs.

In addition, Gartner forecasts that by 2006, IP telephony-line card shipments will exceed those of TDM cards, and furthermore, most PBX vendors will phase out support for the TDM systems.

Changing location

As the technology continues to advance at a rapid pace, the FCC and emergency response teams need an appropriate system to keep up. Businesses, on the other hand, have not only a legal obligation, but also a moral obligation to implement full E911 capabilities in an IP-telephony environment.

The National Emergency Number Association (NENA; www.nena.org) suggests that all IP devices be treated as mobile. These devices include desk phones that, when taken from office to office within an enterprise, let the user maintain the existing extension number.

One of IP's greatest benefits may also be one of its biggest challenges. In an IP network environment, setting up and taking down semi-permanent connections to meet the corporation's requirements is easy. But changes in cabling connections often are not documented appropriately or in a timely fashion. This dynamic network with constantly changing locations ultimately poses difficulties to the public ALI databases.

Since it is vital to understand where the cables go and what devices connect to them, the database requires a system in which MACs are reflected in near-real-time.

Adding intelligence to networks

Enterprises have are responsible for streamlining the process of gathering, updating, and disseminating location details to provide accurate E911 information. MACs, however, pose both significant technical challenges and administration costs. To cope with the increasingly stringent legislation, companies are imposing and trying to enforce internal policies that, for lack of a better solution, forbid employees to move phones. But this approach forfeits a significant advantage of IP technology.

A different approach equips enterprises with up-to-date location information on all IP devices in a network by providing their location through an intelligent physical-layer management (IPLM) system. Some IPLM systems, including RiT Technologies' PatchView system, map end-to-end connectivity, at the logical as well as physical layers, thereby correlating between virtual addresses and their precise physical location. This capability lets network managers control the suite of products in the IPLM system as well as discover other vendor entities, such as switches and terminal equipment.

In addition, an IPLM system includes the ability to work with a computer-aided design (CAD) module to provide an administrator with a full view of physical entities and their exact location within any room in the organization. These combined capabilities let the IPLM system map any IP devices in a network and with the physical location.

Real-time mapping

An enterprise E911 system must be able to handle several types of mobility, including:

  • Keeping track of one's location when moving between two locations in an enterprise;
  • Keeping track of all MACs in the wiring rooms;
  • Keeping track of one's location in a "virtual office."

Acting as an intelligent patch panel for the LAN, the IPLM system provides multi-vendor networks with real-time mapping capabilities of IP address, extension numbers, and location information; the ability to transfer the mapped information to other applications; and a visual layout of a specific location within an operation (i.e., a map of the specific corner of a particular room, floor, and building).

E911 expansion today has become imperative. Analysis conducted by the Monitor Group (www.monitor.com) and published by NENA reveals that Americans are clearly in favor of placing a high priority on upgrading the 911 system.

A Monitor Group survey of 2,712 citizens shows that nearly 60% believe that today's homeland security environment increases the importance of the 911 system. In addition, respondents rate E911 at least as important as a number of other public-policy priorities, with 59% saying 911 is even more important than education.

Many people do not believe they will ever have to dial 911. Unfortunately, experience has shown otherwise, and dialing the three digits can save many lives. Fortunately for enterprises, current IPLM technology offers opportunities to address E911 requirements.

Companies do not have to sacrifice the benefits of IP telephony implementations to comply with legislation. They can achieve the advantages of added mobility that IP phones were designed to provide, as well as gains in IP convergence while enjoying a reduction in operating costs.

Gina Gluch is a writer for the cabling industry. She wrote this article on behalf of RiT Technologies (www.rittech.com).

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