Feature – Ian Stokell’s Guide To Networking Gibberish
MINNEAPOLIS, MINNESOTA, U.S.A., 1997 FEB 28 (NB) — By Ian Stokell. In this week’s column, I take a look at frame relay and where it stands in the industry, in answer to a question from reader William Ng.
Mr. Ng sent me an e-mail asking to explain frame relay. Rather than answer the question myself, I thought I’d get someone involved in the industry to reply. As a result, I spoke to Nina Saberi, president and general manager of NetLink, a Cabletron company.
First, Saberi gave a bit of background concerning frame relay, saying it is a technology that has really emerged since the early 1990s and is “basically a technology that allows connectivity to public networks — it is a stepping stone to complete mesh networking.”
Frame relay is a fast packet technology that is often spoken of in the same breath as asynchronous transfer mode (ATM) for high speed transmissions, but more about that in a moment.
Frame relay is growing in popularity, she said.
“Because it is very economical — the longer the distances are, the cheaper the rates are compared to lease lines — it has gotten very popular, and all the major long distance carriers are offering the service.”
She identified AT&T as the lead frame relay service provider with the largest market share — something between 38-40 percent. AT&T reportedly doubled its capacity last year, and “they are doubling their capacity this year and they are planning to double it next year,” she said.
She also said that the number of ports that are available have doubled and tripled every year since 1994. “And that is expected to double in the three years, each year.”
So how does it differ from ATM? She said the difference is that ATM is better at higher speeds, while frame relay is better for lower. It is not a competing situation between the two, but rather they can exist together. In fact, she said, “the public networks that are offered today that have frame relay, also offer ATM.”
Said Saberi, “This is a technology that makes sense for a speed up to T1 — and it really is not in a competing situation with ATM, it is a very much of a complementary service with ATM.”
She said that, ATM at lower speeds — specifically under T1 — is not very efficient, due to the fact that it has very large overhead.
These two technologies are complimentary, she said. “ATM is more of a ‘core’ technology with higher speed access lines, and frame relay is really related to ports which are at the ‘edge’ — they call frame relay more of an edge technology for speeds up to T1, and then ATM is a core technology for higher speeds.”
Integration of voice and data will be important in the future she said, for both frame relay and ATM.
She then gave a good piece of advise for anyone setting up a network, whether they are concerned with a wide area network (WAN) linkup or a small office local area network (LAN).
“It is not so much that you have to decide among different fast packet switching technologies, it is just that you have to look at your application and see what you are required to do.”
Bottom line: always plan your network in advance, so you know why, as well as how, you are setting up a network.
Finally I asked her why there is less overhead with frame relay, which makes it more efficient.
“Because frame relay was meant for LAN connectivity, so it allows very large packet sizes. A lot of people also use it for SNA (Systems Network Architecture) connectivity, and companies such as Cabletron have special products that provide prioritization and management of protocols so that, whether you have large packets or small packets, you can basically have the most efficient bandwidth management.”
She concluded: “But the fact is, it does allow large packets. ATM packet sizes are fixed at 53 bytes and that’s mostly done because of the fact that ATM is the platform for both voice and data at a higher speed — mostly for T3 and above, although ATM at T1 also exists today. This is all in wide area of course.”
I hope this goes some way to explaining a little about frame relay.
Note: Ian Stokell is Newsbytes’ managing editor and resident networking expert. If you have a question or comment, feel free to drop him an e-mail at Ian_Stokell@newsbytes.com . Non-techie questions welcome.
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