Getting a Circuit When All Circuits Are Busy

The U.S. has a little-known system for emergency workers during times of emergency

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Steven Cherry: Hi, this is Steven Cherry for IEEE Spectrum’s “Techwise Conversations.” This is show number 70.

When a police or ambulance siren sounds, the rest of us get out of its way. Sometimes even those vehicles use the shoulder of the highway during a traffic jam. What about for heavy telecommunications traffic? During a hurricane or a terrorist attack, networks take a double hit: The infrastructure itself can be damaged, and even when it’s not, the flood of people trying to get on the network can make it virtually unusable. Is there a shoulder to the information superhighway that police, emergency workers, and government officials can use? As it turns out, there’s a Government Emergency Telecommunications service, or GETS. GETS was used during and after 9/11 and also for Hurricane Katrina in 2005. The service was created by the National Communications System, which is housed within the U.S. Department of Homeland Security, and there’s a second, comparable service for cellular networks. This year has been a busy one for natural disasters—tornadoes in the Midwest, tropical storms in the Northeast, and even an earthquake near the nation’s capital. How often do these capabilities get invoked, and how exactly does a telecommunications carrier get other phone calls to move out of the way of an emergency? My guest today is the ideal person to answer those questions. Frank Suraci is the technical director for GETS and a member of the National Communications System’s technology and programs division. Frank, welcome to the podcast.

Frank Suraci: Good morning. Glad to be here.

Steven Cherry: Frank, it was a busy year for meteorologists—a perfect trifecta of tornadoes, hurricanes, and earthquakes. Was it a busy year for GETS?

Frank Suraci: Yeah, it sure has been.

Steven Cherry: Let’s look at the two capabilities separately, first for traditional land-line phone networks. How does GETS work? How does a Verizon or AT&T create a fire lane, and who gets to use it?

Frank Suraci: Okay, so we, we developed the capability on the public switch network, and we use the three long-distance carriers, AT&T, Verizon, and Sprint. And it’s a calling card service, and then as far as the local switches, we have GETS priority features in 87 percent of the access lines in the country. So probably the easiest way is to kind of walk you through how a normal—how a call would work.

Steven Cherry: Yeah, tell us how—let’s say I’m the, I don’t know, the mayor or the police chief in Joplin, Missouri, which was one of those tornado towns in the Midwest this spring.

Frank Suraci: So we have an access number that uses the 710 area code, so the person would dial that area code, and then they would be prompted to put in—we call it a personal identification number, a GETS PIN number. And then they’d hear “Enter your destination number,” and then you’d dial, you know, any telephone number, it could even be an international number, so that technically we use features from the beginning of a call setup, and that’s the first end office, or central office, that sees the 710; it, it goes off and gets an AIN feature, which is an Advanced Intelligent Network capability that, that takes the call even if you’re not a subscriber to AT&T, Verizon, or Sprint. And if you’re a subscriber to another carrier, it would automatically put together a table that says, try the call to, you know, say, Sprint on the direct line from the end office to the, to their long-distance network. If that doesn’t work, then there’s an access tandem that end office is tied into—try through the access tandem to get into the long distance. If it didn’t find a path there, it would then try the same thing with Verizon, the same thing with AT&T, so just in a, in a short period of time, you’re actually trying six different attempts to get to the long-distance network. So it’s a pretty powerful capability. And the switches themselves have features built in—like exemptions from network management controls. For example, if there’s an earthquake in California, say that’s a 415 area code, the telephone carriers usually block probably, like, 90 percent of the calls going to that area code, so that will allow people in that area to make calls out. And so a GETS call is exempt from that network management control, so that’s, that’s a feature. And normally you’d get a recording that says all circuits busy, so GETS calls go into a queue, and that first process I talk about, the end office and the access tandem, can then put your call in a queue. And it can be up to 30 seconds before it would time out. And we’d find, probably even with eight times overload, your call will get through in 3 to 4 seconds; so someone’s always hanging up, so you get the next available line. And we don’t preempt any existing traffic with GETS. And then as you proceed on through the long distance, again going through your access authorization with the calling-card number, then there’s features that the long-distance carriers provide alternate routing capabilities within their network, and then as it leaves their network they have—we’ll refer to it as trunk queuing, egressing from their network. And there’s different techniques that the different carriers use—one, they alternate the call back and forth between the end office and access tandem; they can queue it at access tandem and get to the last end office, and you may be in a, beyond a PBX in a office or a hotel, and it would then queue you for a line to free up there. So, so it’s been a pretty powerful capability.

Steven Cherry: How often was it used this year?

Frank Suraci: We actually get—the next day we get operational measures from the switches where there was a GETS call, or else we’ll get onto it later, the wireless priorities service call. So we’ll know there’s activity the following day. And so we know during the year how much it gets used. And—well, I’ll give you an example: When you, we talked about 9/11, we were just doing our acceptance test that morning in New York City. And we were reaching our full operational capability for GETS in September of 2001. And in that situation we had 10 000 GETS calls that were into or out of the Washington D.C area, or the New York City area. And it was 18 000 GETS calls that were made, you know, nationwide. And over 95 percent of those calls completed, which was pretty powerful capability. That was like, the first real use that we had. So then getting on to, like, we had this earthquake here in August, this year. And within those first 2 hours there was, like 3000 GETS calls made and about 95.3 percent of those calls completed. And when we looked at the ones that did not complete, over 70 percent of those were actually to cellphone destinations, and you know, the cellular network was having its—that’s the biggest load you can get when every, when there’s an earthquake, and everybody knows there’s a problem; they all pick their phone up at the same time. Before the week was over, then we had the hurricane, Irene. And the typical pattern—you know about a hurricane coming, so we generally see a rise in the GETS calls, and that was like a Thursday and Friday. And then the landfall was like 7:30 a.m. on Saturday, the first. And then it, it’s pretty mild during that time frame, and then when it’s over we see a rise in the calls as people are then, you know, moving back, and checking on the situation. So that’s the pattern we generally see, you know, with a hurricane, which is totally different. We have that major spike when there’s an earthquake.

Steven Cherry: So how does it work for a cellular network? Can the carriers reserve a space on them as well?

Frank Suraci: Well, just immediately following 9/11, we were asked by the White House to go ahead and provide a cellular capability, priority on the cellular network, you know, initially in New York and Washington, D.C., and then followed by a nationwide capability. So what we did there was we came up with a, what we call a vertical service code, where you dial up a *272 and then any destination number that you want. And that *272 says, “Queue me for a radio channel.” We have priority on the signaling system in GETS, which I didn’t, didn’t mention—that each GETS call is identified in the sending system as a 7. It has a calling party parameter, and it also is one level higher in the signaling system than—the normal POTS calls are set at level zero, and emergency calls, GETS, and 911 are set at level 1 in the signaling system. So that’s a powerful capability when there’s an overload where they have to start shedding calls, and the emergency calls have a higher priority getting through. In the wireless network, early on when we started, the carriers said we have such a, a large segment capacity, it was something you didn’t have to worry about. They were only using, you know, like 5 or 10 percent of the segment capacity back when we first started. And then you’ve seen what’s happened with this dramatic growth in wireless and all the texting and twittering that’s going on, so that, that pretty much gobbled up that capacity.

Steven Cherry: So for GETS, is there just 0 and 1, or is there a 2, and who gets that?

Frank Suraci: In GETS there’s a, there’s just a 0 and 1. And the carrier—there’s two other priorities that the carriers have for care and feeding their network. And now when you jump over to WPS [Wireless Priority Service], we again work through the FCC, and they came out with five party levels for reaching the radio channel. And because that’s such a, you know, a scarcer resource compared to GETS, so that’s prioritized. And when we assign them—I guess we haven’t talked too much about how we go through that process of signing up users, but it serves some of—the White House, the federal government, state and local government, and even industry that supports during emergencies. And there’s some criteria that was established by the White House that if you meet that criteria, you’re entitled to use GETS. And the FCC put out similar criteria in assigning you the priority levels 1 through 5 that you typically can see on our website.

Steven Cherry: You know, nowadays everything is getting merged into Internet traffic, and I would imagine that data itself is becoming more and more important in an emergency. Is, is there a way to create a fire lane on a broadband data network?

Frank Suraci: We’ve been working with the industry and really defining the requirements for how can we provide priority, you know, on the wireless side, on the satellite side, on WiMax, on cable, you know, enterprise, so we initially looked at voice over IP, and right now we’re looking how can we provide priority for the data portion. So that’s ongoing work that the NCA has asked us to do jointly with industry. And these usually go then into the standards body, so everything we do using the public switch network is standard spaced. And so that process is ongoing now, to define how can we get priority on these various data channels, and video and so forth. I think we’ve made pretty good progress on the voice over IP. And we kind of refer to that as our next-generation network that’s out there happening. So we try to get, kind of, hooks in so we get priority, you know, with the packets, in a similar fashion as we had with GETS.

Steven Cherry: Very good. Well, Frank, there’s that old curse and blessing “May you live in interesting times.” Telecommunications technologies keep changing and natural disasters keep coming, and so I think you’re destined to continue living in interesting times. Thanks, thanks for joining us today.

Frank Suraci: Okay. My pleasure.

Steven Cherry: We’ve been speaking with Frank Suraci, the technical director for the Government Emergency Telecommunications Service, about how emergency workers and government officials can continue to communicate when phone networks are flooded with calls.

For IEEE Spectrum’s “Techwise Conversations,” I’m Steven Cherry.

This interview was recorded 12 October 2011.
Audio engineer: Francesco Ferorelli
Follow us on Twitter @Spectrumpodcast

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