Introduction
LAN
forms basis of all commercial,research,and data communication networks.Recently an increase in
applications demand significantly higher band width. Ethernet is an easy to
understand and extremely cost-effective technology. For these reasons, 98% of
local area network (LAN) connections are now Ethernet based.
To meet this,high
speed LAN types have been developed ,including a number of variations of basic
ethernetLANs. CSMA/CD(carrier sense
multiple access with collision detection) is used widely in wired LANs as a
MAC(Medium Acess Control) method.
Transmission medium is coaxial cable (ether) up to 2.5km long,with
repeaters at every 500meters.Upto 256 machines could be attached to the system
via transceivers screwed onto the cable.The system ran at 2.94Mbps
WAN
Ethernet transport has not
yet taken off in the long-haul network, but this is expected to change as
10-Gigabit Ethernet interfaces become available. Some of those are expected to
operate at SONET OC–192 speeds and at the distances needed for long-haul
networks. The distance limitations are not a serious concern because most
long-haul networks use dense wavelength
division multiplexing (DWDM) systems to
combine multiple circuits over a single fiber, each on its own wavelength, and
these DWDM systems provide the long-haul capability themselves. Still, wide-area Ethernet networks are
expected to be implemented, the main reasons being speed, cost, and simplicity.
Future Expectations
Ethernet is (by a huge
margin) the most successful networking technology ever. After all, 99 percent
of all TCP/IP packets (including Internet traffic) traverse an Ethernet somewhere
(and more likely five or six Ethernet LANs in the World Wide Web). And the
future is even brighter! The Radiance Optical Ethernet System is a new breed of
optical access and connectivity that provides a secure, yet manageable,
Ethernet demarcation point between the service provider and business user
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