Most of the companies involved in the Multiservice Switching Forum's GMI 2006 Interoperability event in October toiled to demonstrate global interoperability in an IP multimedia subsystem environment. Sonus, however, was engaged in demonstrating progress in an emergency priority calling system, at the behest of the National Communications System and working with Telcordia and SAIC.

Sonus first teamed with the NCS at the 2004 event to demonstrate emergency features and voice over IP-based next-generation networks features for the Government Emergency Telecommunications Service (GETS). Soon afterward, NCS contracted with Sonus to develop a resource priority header in its code that could be used with GETS, which, along with the Wireless Priority System (WPS), is part of the Information Analysis and Infrastructure Protection Division of the Department of Homeland Security.

This type of emergency calling is unrelated to services such as E911. “In fact, it's the opposite of 911,” said Tom Phelan, principal architect for Sonus. “911 is the public calling the government. This is frontline emergency workers trying to provide services and getting priority access to the network. It allows them to have a high probability of completion. They can get their calls through when other people can't.”

One of the new features that allows this is called Office Wide Call Queuing. It doesn't disconnect calls already established but creates a queue for gaining access to busy trunks rather than simply denying access with a busy signal. Emergency workers put themselves in queue by dialing the GETS number and entering their NCS-approved access code. There are currently around 200,000 people approved for priority access, according to the NCS.

Priority access also allows designated emergency workers to override certain network management traffic controls. When the phone company restricts inbound calls to a disaster area to give people in that area a better chance of calling out, for example, it allows NCS priority users to get their calls in.

For the GMI 2006 demo, Telcordia and SAIC provided custom programming for the session initiation protocol (SIP)-based phones and the Parlay Application Server. The NCS contributed the server while Sonus added the resource priority code and used its GSX Media gateway, Network Border Switch and PSX Policy Router to complete high-priority calls to and from SIP to public networks set up in Verizon's Waltham, Mass., lab.

Phelan called the demonstration a success and said that although the service isn't yet generally available, Sonus hopes to have it certified by the NCS in the first part of next year.

One of the baseline practices of this service is that it doesn't pre-empt calls.

“Once you get your call established, you're not going to get bumped off [the call] by the president, but the president does have a better chance of getting his call connected than you do,” Phelan said.

It would be easy to assume GETS was driven by the events of Sept. 11, 2001, but the system came on-line a couple of weeks before that. However, that emergency did drive the development of the WPS, which came out a year later.

The FCC issued a public comment on this fall's testing. “The events of Sept. 11, 2001, and last year's hurricane season underscored America's dependence on an effective national telecommunications infrastructure,” the statement read. “The new [Public Safety and Homeland Security Bureau] will build on the commission's long-standing commitment to meet the needs of public safety by promoting robust, reliable and resilient communications services in times of emergency.”

GOVERNMENT EMERGENCY TELECOMMUNICATIONS SERVICE

GETS is an emergency communications service used when National Security and Emergency Preparedness (NS/EP) personnel can't complete emergency calls through their regular telecommunications means. GETS

• was developed in response to White House tasking to provide NS/EP users emergency access and specialized processing in local and long-distance telephone networks.
• is accessed through the Federal Technology Service, the Diplomatic Telecommunications Service and the Defense Switched Network. It is in a constant state of readiness.
• uses PINs to give authorized users access and protect against fraud.
• survives numerous switch failures without call disruption because of software enhancements to public network's interconnecting paths.
• triggers Priority Treatment features such as trunk queuing using unique NS/EP codepoints that are carried across the signaling network and exempts users from restrictive network management controls used to reduce network congestion.

Want more?

Check out what your colleagues are reading on Telephony's Most Popular.