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Question 1: Explain the major classification of Computer Networks.
A computer network is a group of interconnected computers. In the world of computers,
networking is the practice of linking two or more computing devices together for the purpose
of sharing data. Networks are built with a mix of computer hardware and computer software.
The network allows computers to communicate with each other and share resources and
Following can be the several factors for classifying different computer networks.
In networking, the communication language used by computer devices is called the protocol.
Yet another way to classify computer networks is by the set of protocols they support.
Networks often implement multiple protocols to support specific applications. Popular
protocols include TCP/IP, the most common protocol found on the Internet and in home
Wired Vs Wireless Networking:
Many of the same network protocols, like TCP/IP, work in both wired and wireless networks.
Networks with Ethernet cables predominated in businesses, schools, and homes for several
decades. Recently, however, wireless networking alternatives have emerged as the premier
technology for building new computer networks.
Computer networks also differ in their design. The two types of high-level network design are
called client-server and peer-to-peer. Client-server networks feature centralized server
computers that store email, Web pages, files and or applications. On a peer-to-peer network,
conversely, all computers tend to support the same functions. Client-server networks are
much more common in business and peer-to-peer networks much more common in homes.
Often, it is impractical for two devices to be directly, point-to-point connected. This is so for
one (or both) of the following contingencies:
The devices are very far apart. It would be inordinately expensive, for example, to
string a dedicated link between two devices thousands of miles apart.
There is a set of devices, each of which may require a link to many of the others at
various times. Examples are all of the telephones in the world and all of the terminals
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and computers owned by a single organization. Except for the case of a very few
devices, it is impractical to provide a dedicated wire between each pair of devices.
The solution to this problem is to attach each device to a communication network.
This is the most basic approach to classify networks. It defines the type of network according
to the geographic area it spans. Local area networks (LANs), for example, typically reach
across a single home, whereas wide area networks (WANs), reach across cities, states, or even
across the world. The Internet is the world's largest public WAN.
WAN spans a large geographic area, such as a state, province or country. WANs often connect
multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs).
Typically, a WAN consists of a number of interconnected switching nodes. A transmission from
any one device is routed through these internal nodes to the specified destination device.
These nodes (including the boundary nodes) are not concerned with the content of the data;
rather, their purpose is to provide a switching facility that will move the data from node to
node until they reach their destination.
The world's most popular WAN is the Internet. Some segments of the Internet, like VPN-based
extranets, are also WANs in themselves. Finally, many WANs are corporate or research
networks that utilize leased lines.
WANs generally utilize different and much more expensive networking equipment than do
LANs. Key technologies often found in WANs include SONET, Frame Relay, and ATM.
In a circuit-switched network, a dedicated communications path is established between two
stations through the nodes of the network. That path is a connected sequence of physical links
between nodes. On each link, a logical channel is dedicated to the connection. Data
generated by the source station are transmitted along the dedicated path as rapidly as
possible. At each node, incoming data are routed or switched to the appropriate outgoing
channel without delay. The most common example of circuit switching is the telephone
A quite different approach is used in a packet-switched network. In this case, it is not
necessary to dedicate transmission capacity along a path through the network. Rather, data
are sent out in a sequence of small chunks, called packets. Each packet is passed through the
network from node to node along some path leading from source to destination. At each node,
Wide Area Network (WAN):