What is network?
Group of networking devices like- computer (P.C), hub,
switch, router, etc. when they are connected together that
Types Of Network
LAN - Local Area Network
Is in a small geographical area, such as a college or office
WAN - Wide Area Network
Combination of multiple LAN.
WLAN - Wireless Local Area Network
Links two or more devices using some wireless distribution
method and usually providing a connection through an
access point to the wider internet.
Local Area Network (LAN)
• A LAN connects network
devices within a limited
geographical area such as
office buildings or schools.
• The data transfer is managed
by a transport protocol such
• The transmission of data is
performed by the access
method (Ethernet, Token
Wide Area Network (WAN)
A WAN covers a wide geographic area, carrying data over
long distances, such as a country
WANs can be formed by different LANs
The connection between different LANs may not be
WANs are sophisticated networks, but transmission speeds
have generally been slower than those commonly achieved
WLAN (Wireless LAN)
A wireless LAN or WLAN is a wireless local area network
that uses radio waves as its carrier
The last link with the users is wireless, to give a network
connection to all users in a building or campus
The backbone network usually uses cables
The wireless LAN connects to a wired LAN
There is a need of an access point that bridges wireless
LAN traffic into the wired LAN
The access point (AP) can also act as a repeater for wireless
nodes, effectively doubling the maximum possible distance
LAN Cable Types
Three cable types are used in LANs:
Straight Cable & Cross Cable
The following diagram shows the Normal use of Crossed
and Straight cables
What is networking?
When all the connected devices can share the resources
such as Data to each other that is networking, like- in our
company there are 100 computers which are connected
together and all 100 computer are able to communicate
The largest public computer network made up of more
than 65 million computers in more than 100 countries
There are more than 20 million hosts on the Internet
(a host is a mainframe or medium to high-end server that
is always online via TCP/IP).
Small Internet Service Providers (ISPs) are connected to
regional ISPs, which are connected to the major backbones
covering Metropolitan areas.
Today, the Internet has become commercialized into a
world-wide information highway, providing information on
every known subject.
An intranet is a computer network that uses Internet
Protocol technology to share information, operational
systems, or computing services within an organization
Organization’s internal network, not for public use like
A Web site for a dedicated audience (e.g. customers…)
rather than the general public. It can provide access to
research, current inventories and internal databases virtually any type of information that is private and not
published for everyone.
An extranet uses the public Internet as its transmission
system, but requires passwords to gain entrance.
The "Access Method" determines how network devices
access the network cable.
Transfers data to and from the connected user's PC on the
Types Of Networking Devices
Networking devices are categorized in layers
Network layer - Router, L3 Switch
Data-link layer - Switch
Physical layer - Hub/repeater
NIC (Network Interface Card)
A Hub is a central connecting device in a star topology
Passive hubs are just connecting devices that add nothing
to the data passing through them.
Active hubs, also called "multiport repeaters", regenerate
the data bits in order to maintain a strong signal.
Share the available bandwidth.
Forward all traffic to all hosts and is therefore inefficient.
It is a networking devices use to connect P.C. it is an
advance of HUB, because it regenerate the data to
destination It works on Hardware address(MAC Address) it
contain MAC address on his memory when data passes
from switch it look MAC address for Source and
Destination and then forward. It works on Data Link Layer.
Router, it is a network device its main function is
Router join minimum two network together that can say
WAN. It works on logical address (IP address),
NIC (Network Interface Card)
A Network Interface Card (NIC) is a circuit board that plugs
into both clients and servers and controls the exchange of
data between them.
A physical transmission medium, such as twisted pair or
coaxial cable, interconnects all network interface cards to
network hubs or switches.
Ethernet and Token Ring are common network interface
Today's cards support 10BaseT and 100BaseT with
There are three main local area network (LAN) topologies:
Other network topologies include: