support for longer cables.
each direction. You implement full-duplex communication by disabling the collision detection
and loopback functions, which are necessary to ensure smooth communication in a shared
network. Only switches can offer full duplex to directly attached workstations or servers.
Shared 100BaseT hubs must operate at half duplex to detect collisions among end stations. Full
duplex is defined by IEEE standard 802.3 and is not a function of Fast Ethernet, which is
defined by IEEE standard 802.3u. Full duplex is a function of Ethernet switches that operate at
100 Mbps.
Ethernet is perfect for deployment on the backbone between 10/100BaseT switches and as a
connection to high-performance servers. With the addition of Gigabit Ethernet, Ethernet
delivers a scalable solution from the desktop (10 Mbps) to the workgroup (100 Mbps) to the
backbone (1000 Mbps). 1000BaseT still has the 100-meter limit on UTP. The IEEE standard
for Gigabit Ethernet is 802.3z for copper and fiber. The standard for UTP is 802.3ab.
multigigabit bandwidth and intelligent services to obtain scaled, intelligent, multigigabit
networks. Since 1999, the Ethernet industry has been working on increasing the speed of
Ethernet from 1 to 10 gigabits per second. This technology is very significant because not
only will Ethernet run at 10 gigabits per second and serve as a LAN connection, but it will also
allow Ethernet to operate in wide-area networks (WANs). With 10 Gigabit Ethernet,
network managers can build LANs, MANs, and WANs using Ethernet as the end-to-end
Layer 2 transport.
LAN technology and is second only to Ethernet in general LAN popularity. When judged solely
on its technical merits, Token Ring might be the logical choice. However, because Ethernet is
less expensive and easier to install and maintain, it remains the predominant protocol of choice
in non-IBM shops. Figure 3-3 shows a Token Ring network.