NX-590E Internet Interface
22
NETWORK
A group of two or more computer systems linked together. There are many
types of computer networks, including:
Local-area networks (LANs): The computers are geographically close together
(that is, in the same building). Most LANs connect workstations and personal
computers. Each node (individual computer in a LAN has its own CPU with
which it executes programs, but it is also able to access data and devices
anywhere on the LAN. This means that many users can share expensive
devices, such as laser printers, as well as data. Users can also use the LAN to
communicate with each other, by sending e-mail or engaging in chat sessions.
LANs are capable of transmitting data at very fast rates, much faster than data
can be transmitted over a telephone line; but the distances are limited, and
there is also a limit on the number of computers that can be attached to a
single LAN.
Wide-area networks (WANs): A computer network that spans a
relatively large geographical area. Typically, a WAN consists of two or
more local-area networks (LANs). Computers connected to a WAN are
often connected through public networks, such as the telephone
system. They can also be connected through leased lines or satellites.
The largest WAN in existence is the Internet.
In addition to these types, the following characteristics are also used to
categorize different types of networks:
Topology: The geometric arrangement of a computer system.
Common topologies include a bus, star, and ring.
Protocol: The protocol defines a common set of rules and signals that
computers on the network use to communicate. One of the most
popular protocols for LANs is called Ethernet. Another popular LAN
protocol for PCs is the IBM token-ring network.
Architecture: Networks can be broadly classified as using either peer-
to-peer or client/server architecture.
Computers on a network are sometimes called nodes. Computers and devices
that allocate resources for a network are called servers.
TCP
Abbreviation of Transmission Control Protocol, and pronounced as separate
letters. TCP is one of the main protocols in TCP/IP networks. Whereas the IP
protocol deals only with packets, TCP enables two hosts to establish a
connection and exchange streams of data. TCP guarantees delivery of data
and also guarantees that packets will be delivered in the same order in which
they were sent.
