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Revive old terminals: remote servers help you capitalize on installed base.


How can I talk to other hosts and networks out there," you ask, "without getting rid of my existing terminal and desktop equipment?"

Lots of ways.

For local-area connections, the answer often lies in remote terminal servers. Costing a few thousand dollars each, servers are used typically on Ethernet LANs to cluster terminals and talk with hosts.

Servers commonly provide DEC LAT (local area transport) connectivity and TCP/IP support for UNIX environments. "The sophisticated ones have a software switch to handle both," sayd Gary Krall of Advanced Computer Communications, Santa Barbara, Calif. When comparing products, consider such factors as price per port and number of ports served.

Also, make sure you're getting LAT and TCP/IP support in the same unit. Some vendors offer both capabilities, but in separate products.

Ron Watkins is network engineer at BBN, a diversified high-tech company in Cambridge, Mass. He's one user who finds servers a very economical way to link terminals to Ethernet hosts and to bridge circuit-switched and netword technologies.

With nearly $1 million invested in PBX and other circuit-switched equipment, he says, "Rather than throw the PBX away as LAN and terminal server technology is utilized, we need a way to blend the two together."

A rack of terminal servers on the company's Ethernet connects hosts not already on the Ethernet to PBX lines.

This way, any user with a circuit-switched connection to his desktop can simply type in "terminal server" at the command line to get to the Annex equipment via a Micom Series 40 PBX, according to Ron Watkins.

When BBN was looking for a way to connect its terminals, it found that circuit-switched access methods cost about $100 a port, while terminal lines run $200 to $250 a port--another reason to get as much mileage as possible out of embedded lines.

Easy Moves, Changes

The setup also simplifies moves and changes. "We can move anybody we want to," Watkins says, "and their office looks the same."

Despite these advantages, Watkins says the terminal-server solution is too slow: "It works, but you can't throw multimedia on an RS-232 line."

Combining E-mail with pictures and voice, or supporting videoconferencing from every desktop via Sun workstations, demands for too much bandwidth. "It's not clear to me that terminal servers will be around a while. You now see workstations and X terminals directly on Ethernet," he says.

These newer terminals support multiple windowing applications at speeds of 10 Mb and above. But terminals servers will last at least as long as industry's huge installed base of modems remains in use, Watkins believes.

At North Carolina State University, a school of about 24,000 students in Raleigh, they're checking out Infotron's Commix 32 as a way of linking some 200 users in six departments to a campus-wide Ethernet supporting TCP/IP and LAT.

The school's academic network supports legions of terminals, PCs, and other devices. "You name it," says Network Analyst Mohammad Fatmi, "the school uses it."

Users served by the Commix 32s occupy three buildings, each with its own LAN. Two buildings are linked directly to the campus-wide Ethernet. The third building houses an INX 4400 data switch that provides various asynchronous services.

Users connected to these boxes can access the INX 4400 services indirectly via two WAN cards in two remote Commix 32s, one connected to the network and the other connected to the 4400.

This facilitates inbound and outbound modem dialing through the switch. Campus users may access outside resources. Off-campus users may tap into the school's Ethernet.

Frozen Boxes

North Carolina State's Computing Center and Infotron have solved a lot of hardware and implementation hitches since beta testing began last summer.

"The boxes used to freeze all of a sudden," Fatmi says. "They'd look like they were working, but no one was communicating." This was due to pesky bugs in the servers' EPROM, the brains of the self-contained units. "As soon as we'd fix one bug, a second would show up."

John Deere, Moline, Ill., a manufacturer of heavy agriculatural equipment, uses Xylogics Annex terminal servers to keep machine tools running smoothly. Three servers in the Dubuque factory each save Deere an hour or two of uptime each day.

"We can pass numerical-control parts programs from the workstation down to the machine tools," says Senior Engineering Analyst Tom Gloden. "The alternative is to read a tape into a machine. This makes it much quicker and easier for the operators to load their next job, and even make changes at machine-tool level and send them back up to the workstation."

Previously, a programmer would create a hard program on a workstation, read it off to a tape punch, punch a tape, take it over to the machine tool, and read it in. Factory dirt often hampered tape reader performance.

The three sites now exchange data at 19.2 kb/s. The servers, which cost about $5000 each, also centralize file storage. "We can use the Ethernet and pass the data, and store the files centrally in a more secure spot," Gloden says. Previously, file storage was performed at a stand-alone disk-drive-equipped workstation.

As LANs multiply, so grows the need for terminal servers. Scott O'Neil, vice president of communications products at Xylogics, marker of the Annex server, says that today only 10% of the installed base of user terminals are on LANs. By the year 2000, however, 80% to 90% will be networked, he says.

Use What's There

Terminal servers help users capitalize on the value of installed bases by acting as switching devices, replacing hardwire connections and port-connection schemes to provide one terminal with multiple connections.

Users want to be sure the investment in TCP/IP equipment they make today will be able to migrate to OSI over the next five or 10 years.

As terminal servers become an embedded part of user networks, users will demand the same multivendor flexibility of them as they now do of terminals. "They expect good software updates, so their networks can keep pace with key trends in communications protocols," O'Neil says.

Terminal servers tend to be clustered on small LANs and must be bridged or routed to environments where computer resources are located.

Mike Lamia, information-systems manager at Sunburst Farms, Miami, doesn't like to "put Ford parts in a Chevy," but he likes the Xylogics MaXserver and ACC bridge addition to his company's all-DEC environment.

The company distributes fresh-cut flowers from South American farms to more than 700 U.S. wholesalers.

It grows and ships only as much as needed. A computerized inventory system facilitates two-hours turnarounds when required.

A DEC VAX connects to the Miami airport and to Sunpetals, a subsidiary that distributes bulk flowers.

"The ways we've connected Sunpetals is a direct leased line from here to Sunpetals--about 12 miles," Lamia explains. "We've attached the bridge to thick coax. We've got an Ethernet band running inside the computer room. We've connected the ACC bridges to the DEC VAX right onto the thick wire. Through a bridge and a 19.2 modem, we're able to connect 16 devices at Sunpetals to the computer system at Sunburst."

Economical Growth

Sunpetals' Ethernet can grow to eight times that without any major cost.

"It's a true Ethernet extension," Lamia says.

"There's no limit to how large they can grow without ever having a computer. The bridge thinks the computer's sitting right next to it. From the computer room we only need to run one thin coax cable to a server. In the departmental areas we run thin, flat wire, like phone wire."

Along with host connectivity, linking LANs poses a challenge for university and business users.

Grand Valley State University, a fast-growing campus in Grand Rapids, Mich., finds Gandalf's StarPort connectivity feature an inexpensive way to link new faculty users while recycling old Gandalf equipment.

The school upgraded its old PACS II (a 1970s data PBX) to a Starmaster network to support more faculty terminal connections to campus services like the library, student information services, and an IBM and Honeywell host.

The Starport feature links 300 asynch network users to campus E-mail.

The "LAN in a drawer" soon will provide access to other existing LANs including a student Token Ring and the Engineering Department's Ethernet.

"A faculty member, in his office, now has a low-cost connection from the Gandalf," according to Director of Information Technologies John Sundstrom. "He calls the Gandalf and it serves him a menu, which says, 'Here are the services available at Grand Valley: the library, the student information system, and the mail system.' We hope soon to get the new LANs in. If they choose the networks, then the Gandalf will call Starport. It will make a LAN connection to allow the person to log on."

Swift Transactions

Investors Fiduciary Trust Co., a Kansas City mutual-fund manager overseeing $10 billion in assets, is counting on a similar setup to speed transaction updates and cut staffing needs.

The company is in the final phases of testing a Starmaster network with the Starport feature.

Its financial tracking network includes an asynch communication server (two PC CPUs running 16 ports each) and an 8900 controller.

"It's cutting our processing time in half," says Systems Manager Doug Bradberry.

"We input trades to the books of the mutual funds through one terminal.

"It updates both 3270 mainframes simultaneously."

The company previously used two points of entry: one from a portfolio accounting system, one from a custody system which tracks securities from purchase to sale.

Error rates are dropping. The new system also allows clients to call into the Starmaster to talk to one of two IBM 3270s or access the company's 100-PC in-house network.

So far Investors Fiduciary Trust saves 30 seconds per transaction.

"We won't have to add staff as we add clients," Bradberry says.
COPYRIGHT 1990 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1990 Gale, Cengage Learning. All rights reserved.

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Author:Jesitus, John
Publication:Communications News
Date:Mar 1, 1990
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