Two users discuss pros and cons of frame relay.
In addition, despite the fact that vendors have announced for more than a year that they are developing frame relay products and services, the availability of frame relay remains extremely limited.
Two companies using some of the few frame relay products on the market are Convex Computer Corp., a Richardson, Tex.-based manufacturer of supercomputers, and Industrial Design Corp. (IDC), a Portland, Ore.-based, employee-owned multidisciplinary design firm that provides engineering and construction management services to high technology industries.
Coyne A. Gibson, MIS computer operations manager at Convex, says his company has deployed a hybrid frame relay network with public and private sections to serve about 1,000 employees.
He says, "We turned to frame relay because it's an interim step toward ATM or broadband ISDN. It's an ideal solution for LAN-to-LAN interconnectivity across a wide area network. There's no performance gain in our environment. But we can do the same job at the same performance level at a much lower cost."
The public portion of Convex's network, in place since early 1991, attaches 13 nodes via WilTel Inc.'s WilPAK fast packet frame relay service. These nodes are primarily smaller sales offices scattered across the United States. Working under the TCP/IP protocol, the network carries data only--electronic mail, sales, order entry and customer support traffic, file transfers and virtual terminal support.
Another 25 nodes are on Convex's private frame relay network, which carries voice, data and video traffic. Both sides of the network use a Stratacom IPX fast-packet, cell-based multiplexer with a frame relay interface that can allow for integration of voice, data and video.
Gibson estimates the recurring cost of a frame relay connection is almost two-thirds lower than for an equivalent T1 set-up.
Also, he says, "Normally, when we design networks, we design them as full or partial mesh networks. That means every node is connected with every other node. So if you take a four-node network and connect it with private lines, you have a total of 12 interfaces on your routers or bridges.
"You have 12 DSU/CSUs, 12 local equipment providers and accesses on the local loop side, and a total of six interexchange lines. With frame relay, the full mesh connectivity is obtained logically instead of physically, so those 12 router interfaces go down to four, one per box.
"DSU/CSU count drops down to four, local equipment lines go down from 12 to four, and you have most of the same functionality in place on the network."
When asked if a network's functionality increases with frame relay, Gibson says, "Your mileage may vary. If you are using an X.25 network, you see increased performance. If you're a private line network user and you had T1 in place before frame relay, you'll see the same relative performance at lower cost." Gibson says frame relay has lived up to his expectations, in part because, "We used it in a laboratory/pilot environment for about two years before we went into serious production with it, so we were familiar with what it could offer."
Randy L. Richardson, systems analyst/telecomm specialist at IDC, says his company ran a trial from Jan. 15 to March 1 using Newbridge Inc.'s Main Street Frame Relay Switch Cards and WilTel's WilPAK. The network on which the products were implemented connects five LANs with about 350 users, many of whom transmit computer-aided design drawings on the network.
WilPAK linked IDC hubs in Portland and Pittsburgh and an office in San Jose. The Newbridge frame relay cards served as switches attached to equipment on the network's nodes.
Richardson says he was disappointed with the failure of WilPAK to handle network congestion management.
"I'm a little bit leery about turning my data over to a network that doesn't have a way to determine how much traffic is on the network," he says. He was also unhappy about its inability to handle bursty data from his LANs.
"Everyone pumped frame relay up as being such a big deal, with the ability to transfer large files at a rapid rate and that kind of stuff. It's basically nothing. Bursting became a non-issue, and in discussing that with WilTel, they agreed that it has been blown way out of proportion."
Richardson discovered he could lower his equipment and line costs by using a private frame relay network. He also gained the ability with the Newbridge frame relay cards to prioritize traffic.
"Frame relay has a lot of advantages for data only usage--cost savings, ease of connectivity, the ability to attach multiple devices to a singe frame stream, prioritization of traffic, congestion management. But it's a data-only situation still."
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|Title Annotation:||Packet Switching/X.25; Convex Computer Corp. and Industrial Design Corp.|
|Author:||Lavallee, Wendy J.|
|Date:||Jun 1, 1992|
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