2. L&T i.e. Larsen & Toubro named on its founder
Henning Holck Larsen and Soren Kristain
Toubro.
L&T is a
technology, engineering, constructions and
manufacturing company.
Basically it consist of many independent
domains such as
Power, Hydrocarbon, InfoTech etc.

3. More than one computer interconnected through
a communication medium for information
interchange is called a computer network.
 A network consists computers that are linked in
order to share resources (such as printers and
CDs), exchange files, or allow electronic
communications.
The computers on a network may be linked
through cables, telephone lines, radio
waves, satellites, or infrared light beams.

4. Twisted Pair
Cable
Optical Fibre
Cable
WIRED
Coaxial Cable
Ethernet Cable
NETWORK 802.11
802.11a
Wireless
Standards
802.11b
802.11g
WIRELESS 802.11n
Wi-Fi
Types Bluetooth
Infrared

5. Networking cables are used to connect one
network device to other or to connect two or
more computers to share printer, scanner etc.
Different types of network cables are:
1. TWISTED PAIR
2. COAXIAL CABLE
3. OPTICAL FIBER CABLE
4. CROSSOVER CABLES

6. STRAIGHT-THROUGH & CROSSOVER CABLES
 Straight-through cables are used to connect different types of
Ethernet equipment—like the connections running from a
computer‘s network interface card to a hub or a switch.
 Crossover cables patch between similar types of equipment having
similar interfaces, like two PCs in a network.

7.  The technology which uses the radio waves to transmit or
receive data is called as Wireless Technology.
 Radio technology is at the base of all wireless
communication, cell phones, in radio broadcasting or in
remote controls.
Sending and receiving radio waves
 Communication through radio waves is achieved by having a
sender that generates the radio waves and a receiver that
picks up the radio waves.
 In wireless networks, devices like laptops, pc’s and smart
phones can both send and receive radio signals in order to
communicate with each other or with an access point.

8.  LAN (Local Area Network)
 MAN (Metropolitan Area Network)
 WAN (Wide Area Network)

9. 802.11
 – Only supported a maximum network bandwidth of 2
Mbps
 – Too slow for most applications. For this reason,
ordinary 802.11 wireless products are no longer
manufactured.
802.11b
 – 802.11b supports bandwidth up to 11 Mbps and uses
the same radio signaling frequency (2.4 GHz) as the
original 802.11 standard.

10. 802.11a
 – 802.11a supports bandwidth up to 54 Mbps and signals in a
frequency spectrum around 5 GHz.
 – Have more difficulty penetrating walls and other
obstructions.
802.11g
 – 802.11g attempts to combine the best of both 802.11a and
802.11b. 802.11g supports bandwidth up to 54 Mbps, and it
uses the 2.4 Ghz frequency for greater range.
802.11n
 – When this standard is finalized, 802.11n connections should
support data rates of over 100 Mbps. 802.11n also offers
somewhat better range over earlier Wi-Fi standards due to its
increased signal intensity.

11.  The OSI (Open System Interconnection) model describes how
information makes its way from application programs through a
network medium to another application program in other computer.
It divides one big problem in to seven smaller problems. Each
problem is addressed by one of the seven layers of the OSI model.

12. Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer

13. Communication Media:
• Communication media is used to transfer data
from one computer to another computer.
• For e.g. twisted pair, optical fibre, wireless, etc.
 NIC:
• NIC stands for network interface card.
• It is a device that physically connects each
computer to a network.
• It controls the flow of information between the
network and the computer.

14. Router
• A router is a device that connects multiple networks
using similar or different protocols.
• It manages the best route between two communication
networks.
Gateway
• The link between two computers to connect to internet
or another network is called gateway.
• Gateways are generally designed and used for LAN-
WAN connections and not for inter LAN
communications.
• A network gateway work like a firewall and filters
packets.

15. Hubs
• Hubs are capable of joining more than two PC but
having some demerits like if two PC would want to
communicate at a time then there would be a collision
and the both PC would have to send the data once
again.
Switch
• This shortcoming of Hub is overcome by Switches.
• Switches are intelligent devices which work on the
Layer2 of the OSI model.
• It builds a MAC address table. So when a frame is
received, it knows exactly which port to send it to.

16.  In general, all of the machines on the Internet can be
categorized as two types: servers and clients.
 Those machines that provide services (like Web servers or FTP
servers) to other machines are servers.
 The machines that are used to connect to those services are
clients.

17. A protocol is the special set of rules that end points
in a telecommunication connection use when they
communicate. Protocols specify interactions
between the communicating entities.
Protocols exist at several levels in a telecommuni-
cation connection.
In Open Systems Interconnection (OSI), there are
one or more protocols at each layer in the
telecommunication exchange

18. Every machine on the internet has a unique
identifying number, called an IP Address.
A typical IP ADDRESS is a 32-bit
number, usually written in dotted decimal
form that uniquely identifies a computer.
Each IP address is split into 2 sections:
1) Network address
2) Host address
For e.g.: 127.0.0.1

19. IPv4 Address Classes
 The IPv4 address space can be subdivided into 5 classes -
Class A, B, C, D and E.
 Each class consists of a contiguous subset of the overall
IPv4 address range.
Class Leftmost bits Start address Finish address
A 0xxx 0.0.0.0 127.255.255.255
B 10xx 128.0.0.0 191.255.255.255
C 110x 192.0.0.0 223.255.255.255
D 1110 224.0.0.0 239.255.255.255
E 1111 240.0.0.0 255.255.255.255

20.  A server is a physical computer dedicated to
running one or more services (as a host), to serve
the needs of users of the other computers on the
network.
 Depending on the computing service that it
offers it could be a database server, file server,
mail server, print server, web server, gaming
server, or some other kind of server.
 The two types of servers are:
1. Rack-mount server
2. Blade server

21. • A rack-mounted server, is a computer dedicated
server and designed to be installed in a framework
called a rack.
• A single rack can contain multiple servers stacked
one above the other.
• The rack server configuration also
simplifies cabling among network
components.

22. • A blade server is a server chassis housing multiple
thin, modular electronic circuit boards, known
as server blades.
• The blades contain
processors, memory, integrated network
controllers and other input/output (IO) ports.
• Each blade in a server is
dedicated to a single application.