Unfortunately, the images are stored in a central computer in Little Rock, the state capital. Whenever a remotely located DMV office tries to download an image from the host to verify a person's identification, the process takes several minutes over the state's SNA (systems network architecture) network.
The image transmissions are necessary because Arkansas and other states have problems with teenagers trying to obtain unauthorized duplicate licenses so they can purchase alcohol.
To overcome the bandwidth problem, the agency is changing to frame-relay technology, which the state has begun to use for its wide area network. Soon, a driver's image will be zipping to DMV offices across the state at 56Kbps rather than the pokey 9.6Kbps common with SNA applications.
Frame relay is a high-speed, packet-switching technology used in wide area networks. Packet switching breaks up messages into smaller packets for transmission. Unlike circuit switching technology, packet networks don't require a constant point-to-point circuit and, because of the their data handling capabilities, frame-relay network providers can charge customers for only the data they transmit.
Arkansas' Departments of Education, Human Services, Finance and Administration, Corrections and the State Police all have, or soon will be using, frame relay to speed up the transfer of information. Not only do the agencies get a big boost in their bandwidth by using frame relay, but it doesn't cost them a whole lot more than slow-moving lines dedicated to SNA traffic.
Other states, including Nebraska, Utah and Massachusetts, are using frame relay, which has become widely available none too soon. "We thought it would be a while before we would need extra bandwidth," said Bob Flynn, network engineer for the Telecommunications Division of Arkansas' Department of Computer Services. "But with the rapid proliferation of PC-based applications, we're having to convert [to frame relay] a lot quicker than we anticipated."
PACKET-SWITCHING TECHNOLOGY
Whether they need to improve driver's license issuance, expand child support services, increase the accessibility of land records or improve how they identify criminals with fingerprints or mugshots, state and local government staff are coming up with dozens of needs for computer applications that run on local area networks (LANs). And as they race to build these systems, cities, counties and states are running into a log jam when they begin to transfer files and information from one LAN to another.
Accustomed to working with a small number of remote sites and sending short bursts of alphanumeric data, agencies now find that with the new applications they need to transfer big chunks of data between many offices with LANs. Lines used for SNA traffic -- virtually the only reason state and local governments had a need for long-distance data transmissions -- are too slow and too expensive. But a frame-relay network resolves both these problems. It can transfer data from 56Kbps to 1.5Mbps and it only requires short access links to the network, thus lowering transport costs.
While leased lines remain the most popular communications channel, with worldwide revenues in excess of $35 billion in 1994, frame-relay use has surged in demand, reaching $1.2 billion in 1995, compared with just $200 million for ATM (Asynchronous Transfer Mode), according to Vertical Systems Group. ATM is much faster than frame relay, able to transfer both data and voice at rates ranging from 25Mbps to 100Mbps, but for a variety of reasons it has been slow to catch on as a popular network technology.
With other network technologies, such as X.25, ISDN (Integrated Services Digital Network) and SMDS (Switched Multimegabit Data Service) either struggling to gain acceptance or
losing their appeal, frame relay
has quietly grown in popularity to become the choice among businesses and government for sending data inexpensively and efficiently between remote sites.
INEXPENSIVE FRAMES
At one point, Nebraska considered deploying a private, statewide network using fiber-optic cables. But economics prevailed and the state worked with local exchange carriers to build a statewide frame-relay network.
In operation for three years now, frame relay is helping the state's agricultural, social service, educational and law enforcement agencies share data between different LANs. Cities
and counties within the state also
have access to the frame-relay network and can share data efficiently and inexpensively.
Cost savings is considered a big benefit when using frame relay. "You
can save as much as 40 percent over leased private lines," said Gerald Hurley, Nebraska's data communications network manager. Other frame-relay users have quoted savings as low as 10 percent and as high as 70 percent. The savings comes from reduced local-access and equipment costs, fewer long-distance circuits and lower management expenses.
Frame relay also provides the amount of bandwidth that governments need today. Agencies will find that frame relay can transmit data at rates that are four times faster than lines used for SNA traffic. While frame relay currently has a limit of 1.5Mbps, most government applications don't need more than that. The Frame Relay Forum, a user's group, estimates that 80 percent of frame-relay users run their networks at 56Kbps.
Frame relay also supports multiple protocols, a must for governments that have legacy applications mixed in with new applications. The most common protocol for data traffic carried on frame relay is TCP/IP, followed by Novell's IPX and SNA. In Arkansas, the state is moving its SNA traffic off private lines and onto its frame-relay network.
According to Hurley, state agencies want to link remote LAN applications to their legacy systems, which is helping to drive the demand for frame relay. "Agencies need to use different protocols in their applications. That's one of the reasons why frame relay is practical," he said.
MEASURING USAGE
Many government agencies are clamoring for better response times and more bandwidth when data must be transferred between LANs. Accustomed to working with data transmission rates on LANs that hit 10Mbps or 16Mbps, agency staff are naturally upset as response times drop precipitously when data is sent from one LAN to the next.
To ascertain whether frame relay is the solution to their problems, communications experts, such as Hurley and Flynn, measure the actual amount of data traffic between LANs. If inter-LAN traffic is sporadic at best, frame relay might not be the best solution. Unfortunately, today's applications typically have fluctuating patterns of use, making it hard to accurately measure network activity between LANs, according to Hurley.
To overcome the problem, engineers can use special probes that measure data traffic. However, they can be expensive. Altogether, the entire assessment process can be "convoluted" as Flynn described it, but the effort will pay off with better information for assessing an application's real response time and the cost of upgrading to frame relay. For instance, it's possible that a remote LAN needs only a dial-up line and a 28.8Kbps modem to improve both response time and bandwidth for data transfers with other LANs.
Government agencies also should be aware that while all the Baby Bells offer some sort of frame-relay service, not all towns have available links. Hurley said he had to work hard at getting the communication carriers to provide links for his independent long-distance and local phone companies. In Arkansas, Flynn said he has had good support from Southwestern Bell and the large number of independent local phone companies.
NEW RACES
FOR FRAME RELAY
No longer considered a new technology, frame relay has been strongly embraced for reducing the cost of data transmissions, providing increased performance, reliability and response time, increasing interoperability, and delivering flexibility as either a private networking technology or as a service provided by public carriers.
Forums and working groups are developing new standards that will not only increase the speed of frame relay, but also allow it to carry voice transmissions. They also are working to use frame relay as an access to the higher-speed ATM network, which is expected to dominate data and voice transmission in the years ahead.
For state and local governments -- where interconnectivity was practically frowned upon just a few years ago -- the need for a wide area network that can provide lots of bandwidth and support interconnections via multi-protocols at an affordable price is a godsend.
In Arkansas, the number of new LANs is increasing and part of the reason has to do with the price and performance improvements frame relay has made to networking. "Our State Police were planning to link eight locations that have LANs," said Flynn. "But when they found out how affordable frame relay was, they bumped the number up to 32 locations." As word spreads and demand for frame relay rises, network engineers, such as Flynn, can expect to be quite busy for some time to come.
Some of the references on network technology used in this article came from Alan Freedman's Computer Desktop Encyclopedia.
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TERMINOLOGY
Switched network: A network in which a temporary connection is established from one point to another for either the duration of the session (circuit switching) or for the transmission of one or more packets of data (packet switching).
Frame Relay: A high-speed packet-switching protocol used for wide area networks(WANs). It is faster than traditional X.25 networks, because it was designed for today's reliable circuits and performs less rigorous error detection. It provides for a granular service up to DS1 rates of 1.544Mbps and is suited for data and image transfer. Because of its variable-length packet architecture, it is not the most efficient technology for realtime voice and video.
SNA: (Systems Network Architecture) IBM's mainframe network standards introduced in 1974. Originally a centralized architecture with a host computer controlling many terminals, enhancements have adapted SNA to today's peer-to-peer communications and distributed computing environment. The seven-layer SNA architecture is very similar to the OSI model, but the functions are not identical.
ATM: (1) (Asynchronous Transfer Mode) A high-speed cell-switching network technology for LANs and WANs that handles data and realtime voice and video. It combines the high efficiency of packet switching used in voice networks. ATM is defined in the broadband ISDN (BISDN) standard.
(2) (Automatic Teller Machine) A Banking terminal that accepts deposits and dispenses cash. Stand-alone or online to a central computer, ATMs are activated by inserting a magnetic card (cash or credit card) that contains the user's account number.
X.25: A 1976 standard for protocols and message formats that define the interface between a terminal and a packet-switching network.
ISDN: (Integrated Services Digital Network) An international telecommunications standard for transmitting voice, video and data over digital lines running at 64 Kbits/sec. ISDN service is increasing in the United States. ISDN uses circuit-switched bearer channels (B channels) to carry voice and data and uses a separate data channel (D channel) for control signals via a packet-switched network. This out-of-hand D channel allows for features such as call forwarding, call waiting and advice of charge. Basic Rate Service (BRI) provides two B channels and one 16Kbps D channel. Primary Rate Service (PRI) in North America provides 23 B channels and one 64Kbps D channel, equivalent to T1. Europe uses 30 B channels and one D channel, equivalent to the European E1 service.
SMDS: (Switched Multimegabit Data Services) A high-speed switched data communications service offered by the local telephone companies (LECs) to interconnect LANs. It uses the IEEE 802.6 DQDB MAN networking technology at rates up to 45Mbps. SONET services at 155Mbps are forthcoming.
TCP/IP: (Transmission Control Protocol/Internet Protocol) A communications protocol developed under contract from the U.S. Department of Defense to internetwork dissimilar systems. It is a de facto UNIX standard, but is supported on almost all computer systems. TCP/IP is the protocol of the Internet.
IPX: (Internet Packet EXchange) A NetWare communications protocol used to route messages from one node to another. IPX packets include network addresses and can be routed from one network to another. An IPX packet can occasionally get lost when crossing networks, thus IPX does not guarantee delivery of a complete message. Either the application has to provide that control or NetWare's SPX protocol must be used.
FRAME RELAY PRICES DROP
Switch vendors are introducing new products that will help reduce the cost of frame relay. Carriers that use the new switches will be able to provide nearly 10 times as many connections for a quarter of current prices, according to Computerworld magazine.
Rick Malone, an analyst at Vertical Systems Group, is quoted by Computerworld as saying that the cost of providing a 56 Kbps connection will drop by as much as 50 percent in the next 18 months.
Analysts believe that the new switches will make it affordable for carriers, including Internet service providers, to add frame-relay services.
SPEAKING, FRAME BY FRAME
Frame relay is not intended to carry realtime voice transmissions. With its packet-switching technology, frame relay is fault-tolerant, allowing packets in a single message to travel different paths to reach the same destination, according to which circuits are available. Since each packet has the same destination address, the computer reassembles the packets back into their proper sequence. Time is not a priority.
Voice, however, is considered time-sensitive. If the transmission doesn't arrive on time, then quality suffers. As a result, voice traffic is considered a high-priority transmission that can degrade network performance, if added to a stream of data flowing through a network.
But earlier this spring, AT&T, frame-relay carrier EMI Communications Corp., and a half-dozen vendors provided demonstrations of voice traffic delivered via a frame-relay network. Private firms that have used the service claim their phone bills dropped as a result. One company used the voice-over-frame service (as it's called) to transmit calls internally to other company locations that are part of its frame-relay network.
While some experts believe voice-over-frame services will only serve a niche and never become widespread, the service is another example of frame relay's expanding use.
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[ September Table of Contents]
