2. What Is Networking ???
A Computer network is set of computer connect together
for purpose of sharing resorce .
The connection between computers are usually physical
Wires or a Cables.
The most common resource shared today is connection
to the Internet. Other shared resources can include a
printer or a file server.
4. Local-area network (LAN)
A local area network (LAN) is a computer network
that interconnects computers within a limited area
such as a residence, school, laboratory, university
campus or office building and has its network
equipment and interconnects locally managed.
LAN encompasses computers and peripherals
connected to a server within a distinct geographic area
such as an office or a commercial establishment.
5. Wide Area Network (WAN) A wide area network is a computer network
that covers a wide geographical area such as
city , country, spans etc.
A WAN uses a communications channel that
combines many types of media such as
telephone lines, cables,
A WAN often makes use of transmission
facilities provided by common carriers, such
as telephone companies. One of the most
prominent examples of the existing wans is
the Internet.
6. Metropolitan Area Network(MAN)
MAN stands for Metropolitan Area Networks is one of a number of
types of networks. A MAN is a relatively new class of network.
MAN as its name implies, covers the area of a single city. MANs
rarely extend beyond 100 KM and frequently comprise a
combination of different hardware and transmission media.
It can be single network such as a cable TV network, or it is a
means of connecting a number of LANs into a larger network so
that resources can be shared LAN to LAN as well as device to
device.
7. Types of communication
There are three types :
1. Unidirectional : -
Two separate channel use for outgoing or incoming of data.
2. Bidirectional : -
Single channel use for outgoing or incoming of data but at a time either outgoing is done or
incoming is done.
3. Multidirectional
Communication can be done in direction in same time.
8. Network Topology
A network topology is the arrangement of a network,
including its nodes and connecting lines. There are two
ways of defining network geometry: the physical
topology and the logical (or signal) topology.
TYPES OF NETWORK TOPOLOGY:
1. Mesh Topology : In a mesh network, devices are connected
with many redundant interconnections
between network nodes.
2. Star Topology : In a star network devices are connected to
a central computer, called a hub.
3. Bus Topology.
4. Ring Topology.
5. Tree Topology.
9. Mesh topology
introduces the concept of routes. Unlike each of the previous topologies,
messages sent on a mesh network can take any of several possible paths from
source to destination. (Recall that even in a ring, although two cable paths
exist, messages can only travel in one direction.) Some WANs, most notably
the Internet, employ mesh routing.
A mesh network in which every device connects to every other is called a full
mesh. As shown in the illustration below, partial mesh networks also exist in
which some devices connect only indirectly to others.
10. Star Topology
Many home networks use the star topology. A star network
features a central connection point called a "hub node" that may
be a network hub, switch or router. Devices typically connect to
the hub with Unshielded Twisted Pair (UTP) Ethernet.
Compared to the bus topology, a star network generally requires
more cable, but a failure in any star network cable will only take
down one computer's network access and not the entire LAN. (If
the hub fails, however, the entire network also fails.)
11. Bus Topology
Bus networks (not to be confused with the system bus of a
computer) use a common backbone to connect all devices. A
single cable, the backbone functions as a shared communication
medium that devices attach or tap into with an interface
connector. A device wanting to communicate with another device
on the network sends a broadcast message onto the wire that all
other devices see, but only the intended recipient actually accepts
and processes the message
12. Ring Topology
In a ring network, every device has exactly two neighbors for
communication purposes.
All messages travel through a ring in the same direction (either
"clockwise" or "counterclockwise"). A failure in any cable or
device breaks the loop and can take down the entire network.
To implement a ring network, one typically uses FDDI, SONET,
or Token Ringtechnology. Ring topologies are found in some
office buildings or school campuses.
13. Tree Topology
A tree topology joins multiple star topologies together onto a
bus. In its simplest form, only hub devices connect directly to the
tree bus, and each hub functions as the root of a tree of devices.
This bus/star hybrid approach supports future expansion of the
network much better than a bus (limited in the number of
devices due to the broadcast traffic it generates) or a star
(limited by the number of hub connection points) alone.
14. Advantages
1. It enhances communication and availability of
information.
2. It allows for more convenient resource sharing.
3. It makes file sharing easier.
4. It is an inexpensive system.
5. It boosts storage capacity.
15. Disadvantages
1. It lacks independence.
2. It poses security difficulties.
3. It allows for more presence of computer viruses and
malware.
4. It requires an efficient handler.
5. It requires an expensive set-up
16. Applications
Sharing of resources such as printers.
Sharing of expensive software's anddatabase
Communication fromone computer to another computer
Exchange of data and information among users via
network
Sharing of information over geographically wide areas.
