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ANA-5910/5930/5940 Use r’s Gui de
Stock Number: 51069 4-00, Rev. C Page: 2-1
Print Spec Number: 493081-00
Current Date: 5/28/97 ECN Date: 05/29/97
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As a technology, ATM represents a sharp departure from LAN
alternatives such as traditional Ethernets th at typically rely on
shared transmissi on media. That is, w ith Ethernet, sev eral nodes
often contend for the right to transmit over shared cable segments
that support only one transmission at a time. When a node
successfully captures the media, it transmits its message at the
maximum allowed speed, complet ely consuming the media.
However, even in the best of circu mstan ces , it i s not unusu al f or two
or more nodes to begin tran smitting at the same time an d interfere
with each others transmission. Ethernet’s design anticipates and
compensates for unpredictable transmission collisions th at occur.
How ATM Works
In contrast to other methods, ATM isol ates ne twork nodes by forc ing
them to attach to ATM switches using dedicated connections. ATM
switches then interconnect and cooperate with each other to form a
network and provide communication connections. While an ATM
node has full use of its switch attachment link, nodes sh are the
capacity of the links connecting the switches. Unlike Ethernet
networks, this sharing i s la rg e ly in vis ible to the nodes. Because of
this and other considerations, ATM provides numerous advantages
and capabilities that are difficult or impossible to obtain with legacy
LAN approaches. Perhaps the most important ATM benefits are its