CHAPTER 7Network

Telecommunications

Types of NETWORK?

A collection of computers There are three types of networks

Local Area Networks Wide Area Networks Internets

Local Area Networks can have two to several hundred at a single location

Wide Area Networks can connect two offices – one in California and the other in New York

Internets use a collection of networks

Components of a Typical LAN

Network Connection

Network OperatingSystem

Network Software

Network Server

Network Interface Card

Workstation Software

Network Operating System (NOS)

Enables the server to manage Data Users Groups Security Applications And other Functions associated to needs of the

Network Other Benefits

Allows remote users to connect Permits users to connect to the Internet Enables additional clients and resources Monitor the status and functionality of the network Distribute programs and software updates to clients

Network Interface Card (NIC) or Controller

All computers have NIC built-in

They come with there own Media Access Control (MAC) address

Has an unique identifier supply by the manufacture It enables you to be tracked on the internet Your IP is left behind wherever you go Without it – you would not be able to share files or

interact with the internet Bottom line – it permits you to access the internet

or a specific networks

General Network – Office/Home

MultiplexerSwitch MultiplexerSwitch

SERVER

NOS

NIC

Router

MultiplexerHUB

Computer

Computer

Computer Peer

Router

Default Gateway They sent information using the best

path to deliver – using multiple networks They direct traffic across the networks They connect to two or more data lines

from different networks Data comes in from one line – router

reads the address in the packet to determine its destination

IP/Subnet/Network IPIP: 192.168.23.77Subnet Mask: 255.255.253.0

IP: 172.30.34.222Subnet Mask: 255.255.255.0

IP: 192.168.23.77SM: 255.255.253.0

IP: 172.30.34.222SM: 255.255.255.0

Router

Network ID: 192.168.23.77

Network ID: 172.30.34.222

LAN

44

Hubs

Are simply a repeater ! It has no intelligences to separate conversations

It’s a dumb device A hub sees a bit or receives a signal – they simply are

going to repeat it – and send the packet of data to a connecting devices or Node To all connecting devices

It has no knowledge of IP addresses This is where the term dummy device comes from

It sends one large bandwidth of information

Node is Latin for “Knot” Refers to a “connecting point” or a redistribution point!

HUB

John

Carol

Betty

David

Provides one huge broadcast to every port or every device

It can cause a collusion with others sending a broadcast

Only one speaker can be talking at one time

Disadvantage! It has no intelligence to separateconversations

Peer-to-Peer (P2P)A network for 10 or fewer users!

Is a distributed application that partitions tasks or workloads between peers (Shares Resources)

It provides a portion of resources such as Gaming Chat Room Shared Resources Processing power Disk storage Cheap, Easy, and

Expandable

Replicated Datai.e. Star Network

How are we able to Communicate

How are we able to connect with other networks

How does the network know how to transfer information from one point to another

How does the network know that the delivery point is correct

How is it possible for me to view my corporate email from multiple computers

Packet Switching

The methodology of sending a file over a network – resembles circuit switching

It selects the quickies route using circuits The bigger the file the long it will take to

receive the file It breaks down big files to smaller files

without overloading the network It has intelligences as it will decide on the

fastest route that is less traveled

Packet Switching

Betty

Steve

1. Doesn’t reserve the entire network from point-A to point-B2. Makes better use of the network by taking the quickest route3. It numbers the files, sorts them out, and eliminates bottle

necking

Transmission Control Protocol Internet Protocol – TCP/IP

TCP/IP Is a set of standards used by computers to

transmit data across wires or wirelessly Standards are hardcoded into each computer so

that one computer sends information to another, they are both using the same methods to translate that data

The most common protocol TCP/IP is an international set of protocols to send

and receive information between two points in a network

Transmission Control ProtocolOpen Systems Interconnection (OSI) Model

Application Layer

Internet Layer

Transport Layer

Network Layer

TCP/IP Stack

Segments

Packets

Frames

Bits

Data

Data

Data

ApplicationProcess to Application

PresentationData Rep. & Encryption

SessionInter Communication

TransportEnd-to-End Connections

NetworkPath Determination

Data LinkPhysical Addressing

PhysicalBinary Transmission

HUB

SWITCH

ROUTER

IP Architecture

IP = 192.168.05.66

Octet

Each Octet = 8-bits Four Octets = 32-bit long and the network reads it as a single stringMOVING to the Future = IPv6 = 128-bit strings

Each Octet can have a number ranging from 0-255

MultiplexerSwitchMarketingDepartment

Sub-Network

Network ID

AccountingDepartment

Sub-Network

HumanResources

Sub-Network

ProductionDepartment

Sub-Network

SalesDepartment

Sub-Network MultiplexerSwitch

MultiplexerSwitch

RouterGateway

WebServer

ProxyServer

NetworkServerProcurement

Department

Sub-Network

Internet

WANLAN

Modem

Router

Top

olo

gy

IP: 255.25.25.01

IP: 255.25.25.02

IP: 255.25.25.03

Broadband

It is a band of frequencies First (back in the day) used in radio The wider (or Broader) the bandwidth of a

channel - the greater the capacity for traffic Refer to fast data transmission rates

Divided into channels Voice or data channels simultaneously Can be use as a high-speed single channel

data transmission

Broadband

Allows us to connect to the internet Enables us to transmit and receive

Information Voice Data Video

Supplies content from the web Enables us to download applications Measured by speed or bits per second

Digital/Analog Modem

• Telephone line• Cable system• Wireless• Analog devices

Transformed into Bit/Binary

01000001 = A01100001 = a

8 bits = 1-Byte*POTS*

Electronic Pulses

1

0

1

1

0 0

1 1

Modulator/Demodulator or ModemEnables switching: Voice/DataData Compression

Wide Area Network (WAN)

Uses Telephone line

(DSL) Digital Subscriber Line

Satelite dishes Radio Waves Cable (ISP)

To span larger geographic areas

Local Area Network (LAN)

Small Office or Home Broadcast is limited

To the area of a Home Small office Area Radius = 50 ft.

Corporations Much more powerful

broadcast Install Repeaters More coverage Radius = 1,640 Ft.

Switch

Has intelligences Memorizes MAC addresses It knows where everyone lives within the

network Delivers information to only the MAC address

in which it is intended Other PC’s attached to the switch would never

know about the information being forwarded It allows more throughput All PC’s connections has full bandwidth No one will experience a collision

Switch

PC #1IP: 198.22.254.1

PC #2IP: 185.33.188.5

PC #3IP: 197.44.197.2

PC #4IP: 174.54.112.8

Nancy Debbie

JanetBill

All members are a part of the same broadcast

domain

Uses: 1-line for receiving and 1-line for sending to each deviceIt can use both simultaneouslyThere is no collisions because it has a dedicated road to travel

Corp

Topology

The term is Greek = “Place” or “study” It is the layout pattern on interconnections It is the physical or logical methodology of the

network It is the virtual shape or structure of a network

Physical design is the devices on the network Office layout, what is going to connect to the network

Logical refers to how data is actually going to be transferred within the network (OSI Model)

Corp

Human Resource AreaRing NetworkDifficult to

trouble shoot!

To add a node – network must be shut down

Old LAN’s uses legacy Token Ring network software!

RingNetwork

IP: 255.25.24.0

1

Host IP: 125.41.48.121

Host IP: 125.41.48.122

Host IP: 125.41.48.123

Host IP: 125.41.48.123

Host IP: 125.41.48.124

P/DomainIP: 255.25.25.01Network IDIP: 255.25.25.02

YOUR IT!

Corp

Ring Topology

Very fast transfer rates – all traffic (packets) travels in the same direction

Adding other nodes – have little impact on bandwidth

Prevents network collisions One cable configuration Disadvantages – for all computers to

communicate with each other, all computers must be turned on!

Accounting AreaStar Network

HUB

Disadvantage: The hub represents a single point of failure!

Peer-to-peer connection to each node

If a node fails – it will have very little effect on the network

Star Network/Topology

Each network host is connected to a central hub

Connects each node to the hub with a P2P connection

All traffic passes through the central hub Easy to added more nodes Usually uses a HUB and a Switch to

complete the network!

Corp

Router

Sales Sub-Network

Marketing Sub-Network

Logical IP addressIP 255.255.255.1

Logical IP addressIP 255.255.255.2

1-broadcase domain

1-broadcase domain

Enables forwarding

messages by acknowledging logical IP

address

HUBSwitch

Corp

Production - Bus Network

Disadvantage – although it is cheap to install, this type of network only has one wire – therefore, it can be a single point of failureIf the network cable breaks, the entire network will be

down!

Most common network!

One virus – everyone is affected!

Limited cable length & number of stations

Bus Network/Topology

All nodes of the network are connected to a common transmission, which has two end-points

Data travels in both directions until the MAC address is found

It has only 1-wire, very inexpensive to implement

The END