?– Computers: Computers serve as the endpoints in the network, sending and receiving
data.
?– Interconnections: Interconnections enable data to travel from one point to another in
the network. Interconnections include these components:
??” NICs: NICs translate the data produced by the computer into a format
that can be transmitted over the LAN.
??” Network media: Network media, such as cables or wireless media,
transmit signals from one device on the LAN to another.
?– Network devices: A LAN requires the following network devices:
??” Hubs: Hubs provide aggregation devices operating at Layer 1 of the OSI
reference model. However, hubs have been replaced in this function by
switches.
??” Ethernet switches: Ethernet switches form the aggregation point for
LANs. Ethernet switches operate at Layer 2 of the OSI reference model
and provide intelligent distribution of frames within the LAN.
??” Routers: Routers, sometimes called gateways, provide a means to
connect LAN segments. Routers operate at Layer 3 of the OSI reference
model.
?– Protocols: Protocols govern the way data is transmitted over a LAN and include the
following:
??” Ethernet protocols
??” IP
??” ARP and RARP
??” DHCP
Functions of a LAN
LANs provide network users with communication and resource-sharing functions,
including the following:
?– Data and applications: When users are connected through a network, they can share
?¬?les and even software application programs.
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