Data communication & Network.

Terms.Communication

 Its means to an exchange of information

between two or more parties &
it can be exchange in a Varity of way.

Data or Computer Communication:

It is the transmission of Data & Information over a

communication Channel between
 two computers which can be several different things.

Channel:

In communications (sometimes called Communications Channel),

refers to the
medium used to convey information from a sender (or

transmitter) to a Reciever


Transmission Media:
It is necessary to have a pathway or the media to be

transmitted data from
one point to another.

The term media means the device that transmits the voice or

the Data from one
media to another.


Guided Media:

In Guided media the mesages flow through the physical media

like
 twisted pair wire,  coxial cable,  fiber optic cables,  the

media guided is the signal.


Unguided (Radiated) Media:
1) Infra-Red
2) Radio & Microwaves
3) Satellites


Signals:

1) Digital Signals
2) Analog Signals

Modem:

A modem is a device that modulates an demodulates the

signals.

Now start Proper Networking.


Network:

Types: 2
1) LAN
2) WAN

LAN: Local Area Network.

WAN: Wide Area Network.

LAN  Cofined to a relatively small area, limited .

Like a Lab, school, 1 building.
On most LANs, cables are used to connect the network

interface cards
(NIC) in each computer.

WAN:  wide area network connect larger geographic areas,

using a WAN,
 Schools in Multan can communicate with places like Karachi

in a matter
 of minutes, without paying enorwous phone bills.


Network Topologies:

the physical arrangement of the computers in a network is

called network topology.

it refers to the configuration of cables, & other

peripherals.
Types:
i)  Ring Topology
ii)  Mesh To..
iii)  StarTo..
iv)  Fully Connected To..
v)  Line To..
vi)  Tree To..
vii)  Bus To..


Network Models:

i)  peer-to-peer networking
ii)  client/server networking model

Connector which we used to connect the cable with p.c is

(RJ-45).

Cables which used for neteorking are (STP & UTP)

STP: Shielded Twisted Pair cable.

UTP: Unshielded Twisted Pair cable.

HUB & SWITCH are used to connect cables through connector in

LAN.

This is the major lacture for networking.

its practical is very easy but know about these things.

UTP cables are connected with RJ-45 Connectors with the

following colors codes:

1) white / green
2) green
3) white / orange
4) blue
5) white / blue
6) orange
7) white brown
8) brown

For connected RJ-45 Connector:

1) Network Interface Card (NIC)
2) Hub
3) Switch

(NIC):
Network cards contain connection for twisted pair cables

(UTP/STP)

HUB:
A hub is a very simple hardware device that supports basic

file sharing
between comuters connected with network cables.

SWITCH:
A switch is a device that provides a central connection point

for cables
 from workstations, servers and peripherals.  in a star

topology.

 Network Topologies:

1) Bus Topology:
a linear bus topology consists of a main run of cable with a

terminator
 at each end. all nodes (file server, workstations, and

peripherals) are
 connected to the linear cable. Ethernet LocalTalk networks

use a linear bus topology.

2) Star Topology
a star topology is a designed with each node (file server,

workstations,
and peripherals) connected directly to a central network hub

or switch.

3) Ring Topology:
a rng network is a topology of computer networks where each

node is connected
 to two other nodes, so as to create a ring.
 ring network carry the disadvantage that if one of the nodes

in the network
 breaks down then the entire network will break down with it

as it requires a
full circle in order to function.
the model used for a network is determined by several factors, including how
 the network will be used, how many users will be on the network, and budgetary
considerations. there are two basic wired network  models from which to choose.

1) peer-to-peer networking:
peer-to-peer networks are cheaper and easier to emplement, making them an ideal
solution for environments inwhich budgets are a concern. this model does not
work well with large number of computer systems. as a peer-to-peer network grows,
it becomes increasingly complicated to navigate and access

Files and resources connected to each computer because thry are distributed
throughout the network.

2) Client/Server Networking Model:

the client/server networking model is, without question, the most widely
 implemented model and the one you are most likely to encounter when working
in real-world environments. it allows for centeralized network management of
all network services, including user management, security, and backup procedures.


Twisted Pair Cables:
1) voice only (telephone wire)
2) data to 4 mbps (localTalk)
3) data to 10 mbps (ethernet)
4) data to 20 mbps (16 mbps token ring)
5) data to 100 mbps (fast ethernet)
6) data to 1000 mbps (fast ethernet)
7) data to 10 gbps (fast ethernet)

RJ-45 Crossover Ethernet Cable:

a good way of remembering how to wire a cressover ethernet cable is to wire
 one end using the T-568A standard and the other end using the T-568B standard.
another way of remembering the color coding is to simply switch the green set
 of wires in place with the orange set of wires.
specifically, switch the solid green (g) with solid orange & switch the
green/white with the orange/white.

 - E-N-D -