Giving voice to convergence
Postal Service IG makes the leap to computer telephony
- By John x_Zyskowski
- Jul 02, 2001
It isn't often that federal information technology managers are given a clean slate on which to design an organization's entire computer and telephone systems. But that was just the opportunity before the staff at the U.S. Postal Service's Office of the Inspector General shortly after Congress created the watchdog agency in late 1996.
One of the boldest decisions the OIG staff made was to build a single network and support organization to handle both data and telephone communications. Besides providing immediate savings in equipment and administrative costs, the converged data and voice network keeps OIG's highly mobile workers connected as their investigative work takes them from one office to another.
"At any time, 40 percent of our staff are on the road, so we needed to create a communications platform that supports them as they move," said Robert Duffy, IT operations manager for the Postal Service's OIG, based in Arlington, Va. OIG staff members investigate waste, fraud and abuse in the postal system and evaluate the efficiency of programs and operations.
The value of starting such a project from scratch should not be underestimated. Fears of turf battles between IT and telecommunications departments—traditionally separate operations—have dampened many organizations' enthusiasm for computer-based telephony. But rather than standing as an exception, OIG's success might serve as a model for federal agencies that want to begin the difficult but potentially worthwhile work of merging the two operations.
Of course, in 1997, when OIG opened its first offices—the Virginia headquarters and three regional sites—computer-based telephony was still unproven in any kind of enterprise environment. So officials installed traditional PBX telecommunications equipment from Nortel Networks Ltd. to serve the immediate need for office phone service.
About a year later, OIG officials got the go-ahead to expand their operations by opening smaller field offices throughout the country. At that point, they thought computer-based telephony, or voice over IP, had progressed enough to consider it as a primary phone system. They could tap the frame-relay wide-area network that provided the data communications between the original offices and use it as the single network for voice and data traffic out to the new field offices.
"To go into these offices and deploy a network line and a telecom line was going to be very expensive, compared to just building one converged network," said James Campbell, OIG's WAN manager.
OIG officials estimated that the integrated voice/data networking gear alone would be 20 percent to 30 percent less expensive than buying separate equipment for voice and data. In addition, because the integrated gear is IP-based, the office's IT staff—which, like most IT shops, was already familiar with IP—could deploy and maintain it with minimal outside help, saving considerable money. Lastly, OIG officials compared the regular monthly cost of traditional phone service using the rates on the governmentwide FTS 2001 telecommunications contract vs. the same services on an integrated IP network. To make an accurate analysis, OIG officials assumed that half the calls on the integrated network would be to traditional, or non-IP, telephones outside OIG offices. In that case, the calls would have to leave OIG's IP-based WAN and travel across the traditional public switched telephone network (PSTN). Even so, the office still found that voice over IP would cost less each month than using the PSTN exclusively.
All the numbers pointed in the direction of voice over IP. "That's the analysis...Inspector General [Karla Corcoran] really wanted to see," Duffy said.
For the rollout of voice over IP, the office chose to go with gear from Cisco Systems Inc., which had supplied the office's existing data networking equipment. OIG officials liked that the Cisco products supported Session Initiation Protocol—a signaling protocol used to establish, maintain and terminate multimedia sessions, including voice-over-IP calls. That would give OIG the option in the future of using standards-based products from other vendors, Duffy said.
OIG's first test of voice over IP was set up between the Arlington headquarters and an office in Atlanta. The beta system included an early version of Cisco's CallManager IP telephony management software, IP phones that connect directly into the local-area network and several multiservice WAN routers. The routers support compression and quality-of-service technologies that help optimize and prioritize the delivery of the voice data.
During the test, there were some early problems with echoing on the line, but those were cleared up when OIG installed the new 3.x version of CallManager, which uses more advanced echo-cancellation techniques, said Mark Yefko, a major account manager with Cisco who worked on the OIG project.
During the test, and even now during the production phase, the voice-over-IP system links to the public telephone network via OIG's Nortel PBX equipment. That connection allows the voice-over-IP system to make calls to phones outside OIG and provides backup phone service in case the VOIP system encounters problems (see diagram, Page 36).
Once OIG employees participating in the test could no longer tell the difference in quality between a voice-over-IP and a traditional call, Duffy said the technology was ready to be rolled out to the field offices.
In preparation, OIG's IT staff also redesigned the WAN to optimize it for voice traffic. "We created multiple subnets to keep down the data-packet collisions" that can adversely affect call quality, Campbell said.
OIG also upgraded the capacity on its WAN. The frame-relay lines from WorldCom Inc. that connected the field offices were upgraded from a committed information rate of 384 kilobits/sec to 768 kilobits/sec to accommodate the new voice traffic, Campbell said.
An upgrade was especially needed for the line into the Arlington headquarters because that office acts as the gateway for all voice-over-IP calls that must cross to the public phone network, even those that originate in the field offices. That "funneling" role for the Arlington site required an upgrade from a T1 line to a channelized T3, also referred to as a DS3. A T3 provides data rates of about 43 megabits/sec, compared with the 1.5 megabits/sec of a T1.
"We'll eventually add a secondary DS3 on the WAN to provide optimization," Campbell said.
OIG currently has about 10 production voice-over-IP sites and plans to expand to 20. One of the key benefits of the system is how efficiently it can be managed. A standard configuration for the field offices eases the installation and troubleshooting later when problems arise.
"We can manage everything from headquarters," Campbell said. "If an employee moves to a new office, you just plug the IP phone into the LAN port in the wall and the system will auto- configure itself, bringing the regular call services to the new location."
Those types of benefits are available to all voice-over-IP adopters, whether they are building a new organization, as the Postal Service OIG did, or are converting an existing shop to IP telephony, Yefko said. "Those that target voice over IP with existing infrastructure get to enjoy cost avoidance in regular system maintenance and can get the increased services that go along with it," he said.
OIG, for example, is building a number of special services that are delivered via its converged network. With one such application, traveling OIG employees can access weather forecasts for selected cities using their IP phones. The system is also a delivery mechanism for an up-to-date employee directory and for broadcasting messages.
Plans for the office's voice-over-IP system include adding video traffic and using "soft phones"—software that turns a regular laptop or desktop computer into a telephone, eliminating the need for a separate telephone handset. OIG officials would also like to phase out the Nortel PBX gear within the next 18 months, which would make OIG one of the first federal offices to use voice-over-IP technology exclusively for all of its calling needs.
Being out in front doesn't appear to be a problem for OIG officials. "To some degree, we went out on a limb with this technology," Campbell said. "When we started, we could have taken the safe route and put in traditional [phone] switches everywhere. In the end, we would have had the same basic service, but not the opportunity to make a big impact with IT in a very dynamic way."