Avoiding heavy traffic
- By Paul Korzeniowski
- May 28, 2001
For decades, most federal government computer networks had a simple job: Move basic data files from one computer to another. It wasn't always fast or fancy, but it worked.
Now this basic role is on the brink of a dramatic change as the once data-only networks increasingly become the conduits for a host of rich media applications, such as computer-based telephony, desktop videoconferencing and telemedicine.
The shift to this new bandwidth- consuming traffic will push traditional networks to their capacity. For their part, network suppliers are trying to forestall a crisis by developing products and services that support a new way of prioritizing traffic called quality of service (QOS).
But the use of QOS capabilities has been limited. "There has been a lot of talk about the need for QOS from vendors on the supply side, but that has not translated into much interest yet on the demand side from customers," said Paul Bugala, a research analyst at IDC, a Framingham, Mass., market-research firm. When that will change remains to be seen. Vendors note the differences even between video and voice applications and say that QOS offers the only way to let all data types live in harmony. The alternative is to simply buy lots of bandwidth, which is what most agencies have done. Buying bandwidth will continue to be a popular approach as long as federal networks remain data intensive. But change is expected. Adoption of voice-over-IP services, which have many attractive features, is on the rise. For example, agencies can merge autonomous voice and IP data networks, which reduces costs and maintenance requirements and increases network efficiency. Also, many agencies are starting to deliver sophisticated, multimedia applications to their users for uses such as distance learning.
Heavy Construction Ahead
Although data was a perfect mate for traditional IP networks, voice and video are not quite as good a match. Those applications are not as forgiving when they encounter bandwidth fluctuations, a common problem on enterprise networks. When that occurs, video transmissions may appear jarring and voice conversations become garbled.
QOS solves such problems by making sure there is a clear link between two endpoints and maintaining it during an entire tranmission. To take advantage of this, agencies need to define policies that outline how network resources are distributed among applications. Then they can give selected applications, such as voice and video, high priority and reduce the chances of an interruption during a transmission.
The feature has strong points, but it also has weaknesses, starting with implementation.
"There is an element of rocket science involved in setting up QOS policies," said David Passmore, research director at the Burton Group, a Salt Lake City-based market research firm. "In certain cases, companies can end up making performance worse if they don't configure their equipment properly."
To implement QOS, a network technician first has to identify how many applications use the network, deduce how much bandwidth they require and determine which systems should receive priority. Then usage must be monitored and changes made as necessary. A simple set of policies might give high priority to online transaction-processing applications, midlevel responsiveness to e-mail and low priority to routine maintenance chores, such as new source-code delivery.
Once the policies are outlined, the IT staff has to enter them into the various network devices that support QOS, often a tedious, time-consuming task.
Suppliers are trying to ease installation. A number of vendors have begun delivering systems in which the user enters QOS parameters once and they are downloaded to all devices on the network. Also, vendors are building more intelligence into their devices so they track transmissions and gauge bandwidth requirements automatically.
Another issue is that QOS has to be supported on each point along a network connection. "You either have end-to-end QOS or no QOS," said Mike Paluzzi, director of federal systems at Alcatel USA Inc., Plano, Texas. Because the typical agency network includes a mix of old and new routers, switches and voice-over-IP switches, chances are high that the equipment comes from multiple suppliers. Vendors have crafted a wide — and ever-growing — array of standards to deliver end-to-end QOS (see "Rules of the road," Page 41). "QOS interoperability is a work in progress," said Joel Conover, a senior analyst with Current Analysis Inc., a Sterling, Va., consulting firm. "Standards are starting to emerge, but vendors often implement them in different manners."
Managerial and political hurdles have also slowed QOS deployment. "When you think of QOS, you view it in terms of slow, medium and fast speeds on a network, and no department wants to get the slow speed," Bugala said.
Consequently, the IT department has to play the role of the United Nations among squabbling countries. In certain cases, departments have formed special committees that ultimately set network priorities.
The various technical and managerial hurdles have limited the application of QOS. Most organizations have been opting for the brute-force bandwidth method: Buy lots of network equipment and let users run whatever they want. That's possible because the price of faster network devices has been dropping. The average per-port price for Gigabit Ethernet switches, which was more than $1,000 in 1999, should drop to $335 by 2003, according to IDC.
Traditionally, agencies have followed the brute-force approach throughout their local-area networks, and in certain cases, they have delivered more bandwidth to their desktop and server systems than they can process. However, wide-area network throughput has been more expensive and has traditionally accounted for the bulk of an agency's telecommunications costs, so the brute-force approach has not been as popular on the long-haul networks.
But even WAN pricing has been falling as new service providers focused on carrying Internet traffic have laid thousands of miles of fiber lines to build nationwide networks. In addition, equipment vendors have improved their top-of-the-line products, so the maximum speeds attainable over a single fiber have quadrupled every two years while the highest number of channels squeezed onto a fiber-optic line has doubled, resulting in an eightfold increase in WAN bandwidth.
"Carriers have been involved in an optical arms race," Passmore said.
That has led to drastic price reductions for WAN services. The gap between T-1 services, which support data rates of 1.544 megabits/sec, and fractional T-1, with bandwidth available in 64 kilobit increments, has dropped to $100 per month in many locations. Also, competitive local-exchange carriers and cable TV service suppliers have been rolling out Digital Subscriber Line and cable modem links, which deliver 1.544 megabits/sec for as little as $50 per month.
So, at the moment, there appears to be plenty of bandwidth available to support new applications. Because vendors have stated that widespread adoption of voice and video applications will drive QOS into the federal market, the question becomes: How close are agencies to deploying those functions?
At one agency, the answer is: "Not too close." Last fall, the Social Security Administration examined ways to improve customer service. The agency handles more than 12,000 telephone inquiries each month and has a set of stand-alone applications that house the data necessary to answer questions. Officials examined integrating the applications to give agents more information and help offload certain questions to its Web site.
They looked at a dozen next- generation call center products based on voice-over-IP technology from vendors such as Cisco Systems Inc., San Jose, Calif.; Siebel Systems Inc., San Mateo, Calif.; and Unisys Corp., Blue Bell, Pa. "We determined that [voice-over-IP] technology is too immature for us to consider deployment at this time," said Lee Wood, an operations manager at the agency's electronic technology center.
What's an agency to do?
"If an agency is located near a carrier's optical hub so there is plenty of bandwidth available in the WAN as well as the LAN, then it may able to continue to use the brute-force approach," Passmore said. "If it isn't, then QOS may be its best option for ensuring delivery of high-quality voice and video transmissions."
Korzeniowski is a freelance writer in Sudbury, Mass., who specializes in technology issues. His e-mail address is firstname.lastname@example.org.