NETWORKS
A network is
the interconnection of a set of devices capable of communication. In this definition,
a device can be a host (or an end system as it is sometimes
called) such as a large computer, desktop, laptop, workstation, cellular phone,
or security system. A device in this definition can also be a connecting
device such as a router, which connects the network to other networks, a
switch, which connects devices together, a modem (modulator-demodulator), which
changes the form of data, and so on. These devices in a network are connected
using wired or wireless transmission media such as cable or air. When we
connect two computers at home using a plug-and-play router, we have created a
network, although very small.
Network Criteria
A network must
be able to meet a certain number of criteria. The most important of these
are performance, reliability, and security.\
Performance
Performance can
be measured in many ways, including transit time and response time. Transit
time is the amount of time required for a message to travel from one device to another.
Response time is the elapsed time between an inquiry and a response. The
performance of a network depends on a number of factors, including the number
of users, the type of transmission medium, the capabilities of the connected
hardware, and the efficiency of the software.
Performance is often evaluated by two
networking metrics: throughput and delay. We often need more
throughput and less delay. However, these two criteria are often contradictory.
If we try to send more data to the network, we may increase throughput but we
increase the delay because of traffic congestion in the network.
Reliability
In addition to
accuracy of delivery, network reliability is measured by the frequency
of failure, the time it takes a link to recover from a failure, and the
network’s robustness in a catastrophe.
Security
Network security
issues include protecting data from unauthorized access, protecting data
from damage and development, and implementing policies and procedures for recovery
from breaches and data losses.
Comments
Post a Comment