Two users discuss pros and cons of frame relay.
As frame relay A high-speed packet switching protocol used in wide area networks (WANs). Providing a granular service of up to DS3 speed (45 Mbps), it has become popular for LAN to LAN connections across remote distances, and services are offered by most major carriers. begins to emerge after much hoopla hoop·la
a. Boisterous, jovial commotion or excitement.
b. Extravagant publicity: The new sedan was introduced to the public with much hoopla.
2. and many promises about its strengths and capabilities, this packet switching A network technology that breaks up a message into small packets for transmission. Unlike circuit switching, which requires the establishment of a dedicated point-to-point connection, each packet in a packet-switched network contains a destination address. technology is getting mixed reviews from end users.
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 Convex Computer was a company that produced a number of vector minisupercomputers, supercomputers for small-to-medium-sized businesses. Their later Exemplar series of parallel computing machines were based on the Hewlett-Packard PA-RISC CPU series, and in 1995, HP bought the 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 See datacenter 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 See BISDN. . 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 TCP/IP
in full Transmission Control Protocol/Internet Protocol
Standard Internet communications protocols that allow digital computers to communicate over long distances. 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 (Internetwork Packet EXchange) The network layer protocol in the NetWare operating system. Similar to the IP layer in TCP/IP, it contains a network address and allows messages to be routed to a different network or subnet. 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 (Digital (or Data) Service Unit/Channel Service Unit) A pair of communications devices that connect an inhouse line to an external digital circuit (T1, DDS, etc.). 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 Your mileage may vary - (Standard disclaimer attached to EPA mileage ratings by American car manufacturers) A ritual warning often found in Unix freeware distributions and elsewhere. Translates roughly as "Hey, I tried to write this portably, but who *knows* what'll happen on your system?" . 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 computer-aided design (CAD) or computer-aided design and drafting (CADD), form of automation that helps designers prepare drawings, specifications, parts lists, and other design-related elements using special graphics- and calculations-intensive 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 Refers to data that is transferred or transmitted in short, uneven spurts. LAN traffic is typically bursty. Contrast with streaming data. 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 The condition of a network when there is not enough bandwidth to support the current traffic load.
congestion - When the offered load of a data communication path exceeds the capacity. management. But it's a data-only situation still."