Networking Notes For DIT Part 1

DIT Networking Notes
All Notes and topics related to Networking
By Mehran khan & Raees Ali Yar
1
CONTENTS
Networking ............................................................................................................................................................................... 3
1. Data Communication............................................................................................................................................. 3
 Message.................................................................................................................................................................... 3
 Sender....................................................................................................................................................................... 3
 Receiver.................................................................................................................................................................... 3
 medium..................................................................................................................................................................... 3
 protocol.................................................................................................................................................................... 3
2. Types of data communication........................................................................................................................... 4
 Simplex..................................................................................................................................................................... 4
 duplex........................................................................................................................................................................ 4
 serial.......................................................................................................................................................................... 4
3. Network........................................................................................................................................................................ 4
 Servers...................................................................................................................................................................... 5
 clients........................................................................................................................................................................ 5
 transmission media............................................................................................................................................. 5
 shared data ............................................................................................................................................................. 5
 local operating system ....................................................................................................................................... 5
4. networking ................................................................................................................................................................. 5
 lan (Local Area Network)............................................................................................................................. 6
 wan (wide area network)............................................................................................................................. 6
 man (Metropolitan Area Network).......................................................................................................... 6
5. topolgy.......................................................................................................................................................................... 6
 Bus Topology.......................................................................................................................................................... 7
 Ring Topology........................................................................................................................................................ 7
 Tree topology......................................................................................................................................................... 8
 Star topology.......................................................................................................................................................... 9
 mesh topology ....................................................................................................................................................... 9
6. OSI model (OPEN system INTERCONNECTION) ......................................................................................10
 Layer 1: The physical layer ............................................................................................................................11

2
 Layer 2: The data-link layer...........................................................................................................................11
 Layer 3: The network layer............................................................................................................................12
 Layer 4: The transport layer..........................................................................................................................12
 Layer 5: The session layer..............................................................................................................................12
 Layer 6: The presentation layer...................................................................................................................12
 Layer 7: The application layer ......................................................................................................................12
7. Cables ..........................................................................................................................................................................13
 Twisted Pair (TP) Cable..............................................................................................................................13
o Shielded Twisted Pair (STP) Cable ...........................................................................................................14
 Coaxial Cable ...................................................................................................................................................14
 Fiber Optic Cable ...........................................................................................................................................15
8. network interface card (NIC) ..........................................................................................................................15
9. Internet, extranet & intranet...........................................................................................................................16
 intranet...................................................................................................................................................................16
 Exranet ...................................................................................................................................................................16
 Internet...................................................................................................................................................................16
10. Modem....................................................................................................................................................................17
 Internal Modem ..................................................................................................................................................17
 external modem..................................................................................................................................................17
11. Hub...........................................................................................................................................................................18
12. bridge .....................................................................................................................................................................19
13. Router.....................................................................................................................................................................19
14. switch......................................................................................................................................................................20

3
NETWORKING
1. DATA COMMUNICATION
The transfer o f data from one place to another place via some electronic source is called Data
Communication.
There are some basic components of data communication which is given below.
 MESSAGE
It is data or information to be communicated.
 SENDER
It is the device which can send this message.
 RECEIVER
It is the device which can receive the message of sender it is also called sink.
 MEDIUM
Medium is the physical path that connects sender and receiver. It is also called
communication channel. It is used to transmit data. The medium can be a copper wire, a
fiber optic cable, microwaves etc.
 PROTOCOL
It is a set of rules that govern the communication between the devices. Both sender and
receiver follow same protocols to communicate with each other.

4
2. TYPES OF DATA COMMUNICATION
 SIMPLEX
A simplex communication system sends a message in only one direction. There is no
ability for the receiver to respond to the message.
 DUPLEX
There are two types of Duplex which is given below
O HALF DUPLEX
A half duplex communication system provide message in both direction. But
only allow transfer in one direction it a time. i.e CB radio, Fax Machine etc
O FULL DUPLEX
A full duplex is a communication that work both way at the same time
i.e telephone, Mobile etc
 SERIAL
Serial communication takes a data communication break it up in to small pieces and
sends the message one bit at a time through a channel. The receiver collects the small
bits and reassembles them to compose the original message. I.e Data send from modem
to the service provider.
3. NETWORK
A network connect two or more devices (Computer, Mobile) etc with each other. And then they
communicate to each other. There are some basic components of network which is given below

5
 SERVERS
Servers are computer that hold share files, programs and the network operating system.
i.e file servers print servers, mail servers, data base servers etc.
 CLIENTS
Clients are computers that access and use the network and shared network resources.
Client’s computers are basically the users of the network as they requested and receive
service from the server.
 TRANSMISSION MEDIA
Transmission media are the facilities used to interconnect computers in a network
i.e fiber cable, coaxial cable, etc
 SHARED DATA
Shared data are data that file servers provide to clients. Such as data files, printer access
programs and Email etc
 LOCAL OPERATING SYSTEM
A local operating system allow personal computers to access file, print to a local printer
and have and use one or more disk and CD drives that are located on the computer such
as MS-Dos, Unix, Linux, Windows Etc.
4. NETWORKING
Networking is the process of establishing that network. There are many types of networking
but some of them are below

6
 LAN (Local Area Network)
A local area network is a network that is restricted to smaller physical area such as
Local office, School or House Etc.
 WAN (WIDE AREA NETWORK)
Wide area network is a computer network that covers relatively large geographical
area such as a state, province or country. In wide area network computers are
connected through public networks such as the telephone system, fiber optic cable
and satellites link or leased lines.
 MAN (Metropolitan Area Network)
A Metropolitan Area Network is a network that connects two or more computers ,
communicating devices or networks that has geographical area larger than a local
Area Network (LAN) and smaller than the area which covered by wide area network
(WAN). Metropolitan Area Network are mostly built for cities or towns to provide a
high data connection and usually owned by a single large organization
5. TOPOLGY
Network topology is the interconnected pattern of network elements. There are two types of
network topology. (1) Physical topology (2) Logical topology physical topology emphasize
the physical layout of connected device and nodes while the logical topology focus on the
pattern of data transfer between network nodes.
There are some basic components of network topology
 Hubs
 Switches
 Bridges
 Routers

7
 Gateway
 Wireless access points (WAPs) Etc
There are some basic Types of Network Topology which is given below
 BUS TOPOLOGY
Bus topology is a network type in which every computer and network device is
connected to single cable. When it has exactly two end points, then it is called
linear bus topology
 RING TOPOLOGY
It is called a ring topology because it forms a ring as each computer is connected to
another computer. With the last one connected to the first, exactly two neighbors for
each device. In ring topology failing of one computer disturb the whole network.

8
 TREE TOPOLOGY
It has a root node and all others nodes are connected to it to forming a hierarchy. It
is also called hierarchical topology. It should it least have three levels to the
hierarchy.

9
 STAR TOPOLOGY
In this type of topology all computers are connected to a single hub through a cable.
This hub is the central nodes and all others nodes are connected to the central
nodes. In star topology failing of one computer cannot disturb the whole network.
 MESH TOPOLOGY
A network setup where each computer and network device is interconnected with
one another, allowing for most transmissions to be distributed, even if one of the
connections goes down. It is a topology commonly used for wireless networks.

10
6. OSI MODEL (OPEN SYSTEM INTERCONNECTION)
OSI (Open Systems Interconnection) is a reference model for how applications communicate
over a network. A reference model is a conceptual framework for understanding relationships.
There are seven layers of OSI Model which are given below.

11
 LAYER 1: THE PHYSICAL LAYER
This layer conveys the bit stream across the network either electrically,
mechanically or through radio waves. The physical layer covers a variety of devices
and mediums, among them cabling, connectors, receivers, transceivers and
repeaters.
 LAYER 2: THE DATA-LINK LAYER
This layer sets up links across the physical network, putting packets into
network frames. This layer has two sub-layers: the logical link control layer and the

12
media access control layer (MAC). MAC layer types include Ethernet and 802.11
wireless specifications.
 LAYER 3: THE NETWORK LAYER
This layer handles addressing and routing the data -- sending it in the right direction
to the right destination on outgoing transmissions and receiving incoming
transmissions at the packet level. IP is the network layer for the internet.
 LAYER 4: THE TRANSPORT LAYER
This layer manages packetization of data, then the delivery of the packets, including
checking for errors in the data once it arrives. On the internet, TCP and UDP provide
these services for most applications as well.
 LAYER 5: THE SESSION LAYER
This layer sets up, coordinates and terminates conversations. Its services include
authentication and reconnection after an interruption. On the internet,
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) provide
these services for most applications.
 LAYER 6: THE PRESENTATION LAYER
This layer is usually part of an operating system (OS) and converts incoming and
outgoing data from one presentation format to another -- for example, from clear
text to encrypted text at one end and back to clear text at the other.
 LAYER 7: THE APPLICATION LAYER

13
This is the layer at which communication partners are identified -- Is there someone
to talk to? -- Network capacity is assessed -- Will the network let me talk to them
right now? -- And where the data or application is presented in a visual form the
user can understand. This layer is NOT the application itself, it is the set of services
an application should be able to make use of directly, although some applications
may perform application-layer functions.
7. CABLES
Cable is the medium through which information usually moves from one network device to
another. There are some specific types of cables. The type of cable chosen for a network is
related to the network's topology, protocol, and size. The types of cables are given below.
 TWISTED PAIR (TP) CABLE
Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded
twisted pair (UTP) is the most popular and is generally the best option for school
networks.
O UNSHIELDED TWISTED PAIR (UTP) CABLE
This cable has four pairs of wires inside the jacket. Each pair is twisted with a
different number of twists per inch to help eliminate interference from adjacent
pairs and other electrical devices. The tighter the twisting the higher the
supported transmission rate and greater the cost per foot

14
O SHIELDED TWISTED PAIR (STP) CABLE
This cable is the least expensive cable, it may be susceptible to radio and electrical
frequency interference (it should not be too close to electric motors, fluorescent
lights, etc). Shielded twisted pair cable is available in three different configurations:
1. Each pair of wires is individually shielded with foil.
2. There is a foil or braid shield inside the jacket covering all wires (as a group).
3. There is a shield around each individual pair, as well as around the entire group
of wires (referred to as double shield twisted pair).
 COAXIAL CABLE
Coaxial cabling has a single copper conductor at its center. A plastic layer
provides insulation between the center conductor and a braided metal shield. The
metal shield helps to block any outside interference from fluorescent lights,
motors, and other computers. Coaxial cabling is difficult to install, it is highly
resistant to signal interference. In addition, it can support greater cable lengths
between network devices than twisted pair cable. The two types of coaxial cabling

15
are thick coaxial and thin coaxial.
 FIBER OPTIC CABLE
Fiber optic cabling consists of a center glass core surrounded by several layers of
protective materials. It transmits light rather than electronic signals eliminating
the problem of electrical interference. This makes it ideal for certain environments
that contain a large amount of electrical interference. It has also made it the
standard for connecting networks between buildings, due to its immunity to the
effects of moisture and lighting. Fiber optic cable has the ability to transmit
signals over much longer distances than coaxial and twisted pair. It also has the
capability to carry information at vastly greater speeds.
8. NETWORK INTERFACE CARD (NIC)
A network interface card (NIC) is a circuit board or card that is installed in a computer so
that it can be connected to a network. A network interface card provides the computer with a
dedicated, full-time connection to a network. Personal computers and workstations on a local
area network (LAN) typically contain a network interface card specifically designed for the
LAN transmission technology.

16
9. INTERNET, EXTRANET & INTRANET
 INTRANET
An intranet is a private network, operated by a large company or other
organization, which uses internet technologies, but is insulated from the global
internet.
 EXRANET
An extranet is an intranet that is accessible to some people from outside the
company, or possibly shared by more than one organization.
 INTERNET
The Internet, sometimes called simply "the Net," is a worldwide system of
computer networks. A network of networks in which users at any one computer
can, if they have permission, get information from any other computer (and
sometimes talk directly to users at other computers). It was conceived by the
Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and
was first known as the ARPANet.

17
10. MODEM
A modem is a device or program that enables a computer to transmit data over, for example,
telephone or cable lines. Computer information is stored digitally, whereas information
transmitted over telephone lines is transmitted in the form of analog waves. A
modem converts between these two forms. There are two main sub types of modem
 INTERNAL MODEM
An internal modem is a network device that is contained on an expansion board
that plugs into the motherboard. Unlike an external modem, an internal modem
contains no lights to inform the user of its current function or changing modem
states. Instead, the user must rely on the software that came with the modem.
Internal modems are also known as on-board modems.
 EXTERNAL MODEM
An External modem is a self-contained modem that is connected to the serial or
USB port of a computer. The older serial port models draw power from a wall
outlet and have the advantage of status lights on the outside of the case that show
the changing states of the modem (off-hook, carrier detect, transmitting, etc).

18
11. HUB
A hub, also called a network hub, is a common connection point for devices in a network.
Hubs are devices commonly used to connect segments of a LAN. The hub contains
multiple ports. When a packet arrives at one port, it is copied to the other ports so that all
segments of the LAN can see all packets. A hub is the most basic networking device that
connects multiple computers or other network devices together. Unlike a network switch or
router, a network hub has no routing tables or intelligence on where to send information and
broadcasts all network data across each connection.

19
12. BRIDGE
A network bridge is a computer networking device that creates a single aggregate network
from multiple communication networks or network segments. This function is called network
bridging. Bridging connects two separate networks as if they were a single network.
13. ROUTER
A router is a networking device that forwards data packets between computer networks.
Routers perform the traffic directing functions on the Internet. A data packet is
typically forwarded from one router to another router through the networks that constitute
an internetwork until it reaches its destination node. A router will have at least two network
cards (NICs), one physically connected to one network and the other physically connected to
another network. A router can connect any number of networks together providing it has a
dedicated NIC for each network.

20
14. SWITCH
A switch is a network hardware device that allows communication between devices within a
network. Switches are found in both unmanaged and managed forms. Unmanaged switches
have no options and simply work out of box. Managed switches have advanced options that
can be configured. Switches connect to other network devices via network cables only and
thus do not require drivers to operate in Windows or other operating systems.
Router

21
This is the complete Topics related to DIT (Networking).
Written by Mehran Khan and Raees Ali Yar.

Networking Notes For DIT Part 1

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie Networking Notes For DIT Part 1

Ähnlich wie Networking Notes For DIT Part 1 (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Networking Notes For DIT Part 1