Go tell it on the mountain - Moody Bible Institute installs fiber ring network - Company Operations

Communications News, Sept, 1999 by Chris Harrison

Media converters solve Bible college's networking problem.

Like a juicy peach on an out-of-reach branch, sometimes the perfect networking solution seems to dangle elusively before us. At Moody Bible Institute (www.moody.edu), Chicago, Ill., Paul Siebold, department manager for engineering systems, wanted a network to link the college's many buildings to the physical plant's building management system.

A year ago, there was no network in place. Access to the network was via dial-up to a server. Since the school consists of a central campus area and several other buildings scattered around a 12-block area in downtown Chicago, this proved cumbersome and quite unsatisfactory.

Last summer, the school bored and placed conduit between buildings and now has a fiber ring that links the entire campus. The fiber is owned by Moody and handles both Information Systems' 100Base-FX network and all of the building-management functions from the physical plant. The physical plant uses a building-management system from Andover Controls that monitors and regulates everything from heating and air conditioning to security card and keypad access, as well as fans, boilers, and water pumps.

However, linking a pair of different media like coax and fiber--with the fiber running at different speeds--proved to be a challenge. Especially vexing was finding a way to connect the 10/100 autosensing switches without crashing the network or simply being unable to "see" devices that were attached.

"When we laid the fiber last year, we were able to build a network allowing us to put our building-management controllers together," Siebold says. It is on a 100Base-T Ethernet network and is separate from the information services network.

"I needed something to connect all of this together," he says. Most of the building management network is 10Base-2 (coax). "I wanted the server and the work-stations we were using to do our programming to be at 100 Mbps since we do pass graphics on them," he continues.

"I was not interested in spending large amounts of money on fancy switches that could give me all kinds of port combinations I might want," Siebold says. "So, I bought NetGear's FS-508 8-port 10/100 auto-sensing switches. They allow us to connect the 10-Mbps controllers, 100-Mbps workstations, and server together."

CONVERSION DEVICES

"I wanted a 100FX backbone, so I needed 100Base-TX to 100Base-FX converters," Siebold says. He looked at a variety of companies that make converters and found that no one had a product that was compatible with the auto-sensing technology. Although auto-sensing switches are fairly common in the industry at the time, nobody made converters for them. "It was an industry problem," he says. "Everybody was making the switches, but none of the converters were able to talk to them."

As a result, they blocked the exchange of auto-sensing information, making it necessary to manually configure the hub, switch, or router port to either full or half duplex. In the best case, this required time-consuming intervention at the management console (or removing the cover to configure dip switches). In the worst case, it wasn't possible to make the link come up in the proper mode.

Siebold spoke with Anne Hunsaker, senior account manager at Transition Networks. "Fortunately, she was aware of the problem, and Transition was a/ready working on it. She was very helpful," he says. "I told her that it appears the devices wanted to see a 100 port. But my 10/100 switches say that, unless told otherwise, they will treat the link as a 10. The switches insist on auto sensing (that's their reason for existence). None of the converters on the market could handle the problem."

Hunsaker told him that Transition was developing a new Fast Ethernet converter to handle the problem. Hunsaker obtained two prototype standalone units for Moody. "We plugged them in, and they worked fine," says Siebold. "They just came right up and everything worked the way it was supposed to work."

Siebold got the first order of the new converters and was able to complete the network. "We put them in and, quite frankly, I've forgotten about them. They just work. They give us no trouble," he says.

Transition specializes in media-conversion technology and was the first to solve the auto-switching problem. Because the converter offers a selectable half/full-duplex switch, Transition is the only conversion provider that can guarantee compatibility with any 10/100 Ethernet port.

In addition to the 100Base-TX to 100Base-FX converters, Moody also deploys 10Base-2 to 10Base-T and some 10Base-2 to 10Base-FX connections.

By using media-conversion technology, Moody Bible Institute was able to link a variety of cabling types on its network. In simple terms, media conversion converts one media type to another, making one type of cable or connector look like another without changing the nature of the network. More important, media conversion allows upgrades in performance without the significant costs associated with recabling the plant.