Last week we talked about the enterprise's burgeoning need in about 1990 to provide for a growing number of sites served with more and more router ports. This need was created by a fundamental shift to distributed networking.
Low-speed private lines had worked well for the world of mainframe computers; the architecture supported an inherent packet switch (the computer itself). But the post-1990 world of routers was one in search of a carrier data-switching infrastructure. Enter a new protocol called frame relay.
Frame relay is a connection-oriented protocol and well suited to a simple data switching infrastructure, unlike connectionless protocols such as IP. Frame relay can guarantee bandwidth and throughput across the network using a technique called committed information rate. Properly engineered, frame relay can act like a private line. But, unlike a time division multiplexed (TDM) private line, frame relay has the advantage of statistical multiplexing, so unused bandwidth can be shared between multiple users.
Frame relay also supports variable length frames and can easily encapsulate a variety of protocols, including both SNA and IP. For this reason, both mainframe traffic and LAN traffic can be easily interspersed on the same physical connection.
Frame relay has evolved to become the mainstay of distributed networking WAN data traffic, solving the problem of wasted bandwidth inherent in sending data over a TDM core. But how good is frame relay for voice? Next time, we'll talk about how frame relay networks can also support voice connections.
RELATED LINKS
Steve Taylor is President of Distributed Networking Associates and Publisher/Editor-in-Chief of Webtorials.Com. For more detailed information on most of the topics discussed in this newsletter, connect to Webtorials.Com, the first Web site dedicated exclusively to market studies and technology tutorials in the Broadband Packet areas of Frame Relay, ATM, and IP.
Larry Hettick is an independent consultant, with 19 years of experience in telecommunications and data communications marketing and product management for service providers and equipment vendors. He can be reached at larry@larryhettick.com
You can reach the authors at taylor@webtorials.com or larry@larryhettick.com.
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