COMPUTER EDUCATION 9

MODULE 4Network Connectivity

Prepared By: Engr. Jeremy M. Flores

COMMUNICATION

We live in a truly connected society. We can

communicate almost instantaneously with

others worldwide.

COMMUNICATION

As the power and flexibility of our communication systems

have expanded, the sophistication of the networks

that support these systems has become increasingly

critical and complex.

COMMUNICATION

Computer communication is the process of sharing

data, programs, and information between two

or more computers.

COMMUNICATION

Electronic MailTexting and Messaging

Internet TelephoneElectronic Commerce

CONNECTIVITY

Connectivity is a concept related to using computer

networks to link people and resources.

THE WIRELESS REVOLUTION

The single most dramatic change in connectivity and communications in

the past few years.

THE WIRELESS REVOLUTION

It refers to the widespread use of mobile devices like smartphones and tablets

with wireless Internet connectivity.

THE WIRELESS REVOLUTION

So, what’s the revolution?

Today’s mobile computers support E-mail, Web

access, and variety of Internet applications.

THE WIRELESS REVOLUTION

Most experts say that the Wireless Revolution is just

in its beginning phase.

COMMUNICATION SYSTEMS

It is an electronic systems that transmit data from one location to another,

whether wired or wireless.

COMMUNICATION SYSTEMS

Four Basic Elements

Sending / Receiving DevicesConnecting DevicesData Transmission

SpecificationCommunication Channel

COMMUNICATION SYSTEMS

COMMUNICATION SYSTEMS

Sending / Receiving Devices

These are often a computer or specialized communication devices that originate and

accept messages in the form of data, information, and/or

instructions.

COMMUNICATION SYSTEMS

Connecting Devices

These devices act as an interface between the sending and receiving

devices and communication channel.

COMMUNICATION SYSTEMS

Connecting Devices

They convert outgoing messages into packets that can

travel across the communication channel and

reverse the process for incoming messages.

COMMUNICATION SYSTEMS

Data Transmission Specification

These are rules and procedures that coordinate the sending and receiving devices by precisely

defining how the message will be sent across the communication

device.

COMMUNICATION SYSTEMS

Communication Channel

This is the actual connecting or transmission medium that carries the message. It can be

physical wire or cable, or it can be wireless.

COMMUNICATION CHANNELS

Communication Channels are essential elements of

every communication system. These channels

carry out the data from one computer to another.

COMMUNICATION CHANNELS

Two Categories

Physical ConnectionWireless Connection

COMMUNICATION CHANNELS

Physical Connection

It uses a solid medium to connect sending and

receiving devices.

COMMUNICATION CHANNELS

COMMUNICATION CHANNELS

Twisted-Pair Cable consists of pair of copper wires that

are twisted together.

Shielded Twisted-Pair (STP) Unshielded Twisted-Pair

(UTP)

COMMUNICATION CHANNELS

Coaxial Cable, a high frequency transmission

cable, replaces the multiple wires of telephone lines

with a single solid-copper core.

COMMUNICATION CHANNELS

Fiber Optic Cable transmits data as pulses of light

through tiny tubes of glass, and rapidly replacing

Twisted-Pair cable telephone lines.

COMMUNICATION CHANNELS

Fiber Optic Cable has over 26,000 times the

transmission capacity of Twisted-Pair Cable.

Compared to Coaxial Cable, it is lighter, faster, and more reliable in transmitting data.

WIRELESS CONNECTIONS

They move data through the air and use radio

waves to communicate.

WIRELESS CONNECTIONS

BluetoothWireless Fidelity (Wi-Fi)

MicrowaveWiMax

Long Term Evolution (LTE)Satellite

WIRELESS CONNECTIONS

Bluetooth is a short range communication standard that transmits data over short distances of up to approximately 33 feet.

WIRELESS CONNECTIONS

Wireless Fidelity (Wi-Fi) uses high-frequency radio signals to transmit data. Most home and business

wireless networks use Wi-Fi.

WIRELESS CONNECTIONS

Microwave communications uses high-frequency radio

waves. It is sometimes referred to as line-of-sight communications because it can only travel in a straight

line.

WIRELESS CONNECTIONS

WiMax, Worldwide Interoperablity for

Microwave Access, is a new standard that extends the range of Wi-Fi networks

using microwave connections.

WIRELESS CONNECTIONS

LTE, Long Term Evolution, the newest wireless

standard, promises to provide greater speed and quality transmission in the

near future.

WIRELESS CONNECTIONS

Satellite Communication uses satellites orbiting

about 22,000 miles above the earth as microwave

relay stations.

WIRELESS CONNECTIONS

Many of these are offered by Intelsat, the International

Telecommunications Satellite Consortium, owned by 114 governments and forms a worldwide communication

system.

WIRELESS CONNECTIONS

UPLINK is a term relating to sending data to satellite.

DOWNLINK refers to receiving data from

satellite.

WIRELESS CONNECTIONS

Global Positioning System (GPS) is one of the most interesting application of Satellite Communications.

CONNECTION DEVICES

Telephones typically send and receive Analog

Signals.

Computers send and receive Digital Signals.

ANALOG AND DIGITAL SIGNALS

MODEMS

The word MODEM is short for MOdulator-DEModulator.

It enables digital microcomputers to

communicate across different media.

MODEMS

Modulation is the process of converting from digital to

analog.

Demodulation is the process of converting from analog to

digital.

TRANSFER RATE

This is the speed by which modems transmit data.

MODEMS

Four Commonly Used Modems

TelephoneDigital Subscriber Line (DSL)

Cable ModemWireless Modem

MODEMS

MODEMS

A Telephone Modem is used to connect a

computer directly to a telephone line. It can either be internal or

external.

MODEMS

A Digital Subscriber Line Modem uses standard phone lines to create a high-speed connection directly to your phone

company’s office.

MODEMS

A Cable Modem uses the same coaxial cable as your

television and creates a high-speed connection.

MODEMS

A Wireless Modem, also known as WWAN (Wireless

Wide Area Network), usually uses a small plug-in USB or

ExpressCard device that provides very portable wireless connectivity.

CONNECTION SERVICES

Dial-Up ServiceDigital Subscriber Line (DSL)

Asymmetric DSL (ADSL)Cable Service

Satellite Connection ServiceCellular Service

DATA TRANSMISSION

Bandwidth is a measurement of the width or capacity of the

communications channel. Effectively, it means how much information can move across the communication channel in

a given amount of time.

DATA TRANSMISSION

Four Categories of Bandwidth

VoicebandMedium Band

BroadbandBaseband

DATA TRANSMISSION

Voiceband, also known as low bandwidth, is used for

standard telephone communication.

DATA TRANSMISSION

Medium Band is used in special leased lines to

connect midrange computers and mainframes as well as to

transmit data over long distances up to a very high

speed transfer rate.

DATA TRANSMISSION

Broadband is widely used for DSL, cable, and satellite

connections to the Internet. Several users san

simultaneously use a single broadband connection for high-speed data transfer.

DATA TRANSMISSION

Baseband is widely used to connect individual computers that are located close to one another. Though it is able to

support high-speed transmission, it can only carry

a single signal at one time.

PROTOCOLS

Protocols are sets of communication rules for the

exchange of information.

HTTP and HTTPSTCP/IP

PROTOCOLS

TCP/IP (Transmission Control Protocol / Internet Protocol) involves identifying sending and receiving devices, and breaking information into

small parts for transmission across the Internet.

NETWORKS

A Computer Network is a communication system

that connects two or more computers so that they

can exchange information and share resources.

SPECIALIZED NETWORKS TERMS

Node / Client / ServerDirectory Server / Host

Router / SwitchNetwork Interface Card (NIC)Network Operating System

(NOS)Network Administrator

SPECIALIZED NETWORKS TERMS

Node is any device that is connected to a network. It

could be a computer, printer, or data storage

device.

SPECIALIZED NETWORKS TERMS

Client is a node that requests and uses

resources available from other nodes. Typically, a

client is a microcomputer.

SPECIALIZED NETWORKS TERMS

Server is a node that shares resources with other nodes. Depending on the task they may be called an application

server, communication server, file server, printer server,

database server, or web server.

SPECIALIZED NETWORKS TERMS

Types of Server

Centralized ServerDedicated Server

SPECIALIZED NETWORKS TERMS

Directory Server is a specialized or dedicated

server that manages resources, such as user accounts, for an entire

network.

SPECIALIZED NETWORKS TERMS

Host is any computer system that can be

accessed over a network.

SPECIALIZED NETWORKS TERMS

Router a node that forwards or routes data

packets from one network to their destination in

another network.

SPECIALIZED NETWORKS TERMS

Switch is a central node that coordinates the flow

of data by sending messages directly between sender and receiver nodes.

SPECIALIZED NETWORKS TERMS

A hub previously filled the role of a switch by sending a received message to all connected nodes, rather than just the intended

node.

SPECIALIZED NETWORKS TERMS

A Network Interface Card (NIC) is an expansion card

located within the system unit that connects the computer to

a network. It is sometimes referred to as LAN Adapter.

SPECIALIZED NETWORKS TERMS

A Network Operating System (NOS) controls and coordinates the activities of all computers and other

devices on a network.

SPECIALIZED NETWORKS TERMS

A Network Administrator is a computer specialist

responsible for efficient network operations and implementation of new

networks.

NETWORK TYPES

Home NetworkPersonal Area Network

Local Area NetworkWireless LAN

Metropolitan Area NetworkWide Area Network

NETWORK TYPES

Home Network is commonly used by

individuals in their homes and apartments and can be connected in a variety

of ways.

NETWORK TYPES

Personal Area Network is a type of wireless network that works within a very

small area, such as cellphone to headset,

keyboard to cellphones, PDAs to other PDAs.

NETWORK TYPES

Local Area Network is a computer network with nodes that are in close

physical proximity, within the same building for

instance.

NETWORK TYPES

Wireless LAN is a Local Area Network that typically uses radio frequencies to connect computers and other devices.

All communications pass through the network’s Wireless Access Point or Base Station.

NETWORK TYPES

Metropolitan Area Network spans distances up to 100 miles and are frequently

used to link between office buildings that are located

throughout a city.

NETWORK TYPES

Wide Area Network is a countrywide and worldwide

network, typically spans distances greater than 100 miles, and uses microwave

relays and satellites to reach users over long distances.

NETWORK TYPES

The primary differences between the network

types is the geographic range.

NETWORK ARCHITECTURE

Network Architecture describes how a network

is arranged and how resources are coordinated

and shared.

NETWORK ARCHITECTURE

Bus TopologyRing TopologyStar TopologyTree TopologyMesh Topology

NETWORK ARCHITECTURE

In Bus Topology, each device is connected to a common cable called a

bus or backbone, and all communications travel

along this bus.

NETWORK ARCHITECTURE

In Ring Topology, each device is connected to two

other devices forming a ring. When a message is

sent, it is passed around the ring until it reaches the intended destination.

NETWORK ARCHITECTURE

NETWORK ARCHITECTURE

In Star Topology, each device is connected directly to a central network switch.

Whenever a node sends a message, it is routed to the switch, which then passes

the message to the recipient.

NETWORK ARCHITECTURE

NETWORK ARCHITECTURE

In Tree Topology, each device is connected to a

central node, either directly or through one or more other devices. It is also known as Hierarchical

Network.

NETWORK ARCHITECTURE

NETWORK ARCHITECTURE

In Mesh Topology, each node is required to have

more than one connection to the other nodes and

does not require a specific physical layout.

NETWORK ARCHITECTURE

NETWORK STRATEGIES

Client/Server NetworkPeer-to-Peer Network

NETWORK STRATEGIES

Client/Server Network uses central computers to

coordinate and supply services to other nodes on

the network.

NETWORK STRATEGIES

NETWORK STRATEGIES

In a Peer-to-Peer (P2P) Network, nodes have

equal authority and can act as both client and

server.

ORGANIZATIONAL NETWORKS

An Intranet is a private network within an organization

that resembles the Internet.

An Extranet is a private network that connects more

than one organization.

ORGANIZATIONAL NETWORKS

NETWORK SECURITY

A firewall consists of hardware and software that

control access to a company’s intranet and other internal networks, through a special software of computer

called Proxy Server.

NETWORK SECURITY

Intrusion Detection System (IDS) works with firewall to protect and organization’s network. It can recognize signs of network attack by

pattern matching and heuristics.

NETWORK SECURITY

A Virtual Private Network (VPN) create a secure

private connection between a remote user and an organization’s

internal network.