Transcript Networking Fundamentals

FCN week 8
Lecture 8
Networking Fundamentals
FCN week 8
Principles of Networking
 People use different types of networks every day:
•Mail delivery system
•Telephone system
•Public transportation system
 Networks are systems that are formed by links.
 Computers can be linked by networks
•Corporate computer network
•The Internet
 A network can be as simple as two computers connected by a
single cable or as complex as hundreds of computers
connected to devices that control the flow of information.
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Networking Roots
 PCs: Personal computers with:
Processor, memory, storage
Made computing affordable
Drawbacks:
Isolation of data, difficult to share
Security risks: Physical access granted access to data
 Traditional, early mainframe environment:
Dumb terminals
Central mainframe computer
 Networks: Primarily desktop PCs connected
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Why do we use networks?
 Generally for “connectivity”…
 The need to communicate with others
 Hardware resource sharing
 e.g. printers, mapped drives
 Application sharing
 e.g. administrative systems
 Group working
 e.g. video conferences
 Backup and data security
 e.g. duplicate data in separate physical location
 Remote configuration and management
 e.g. technical staff can audit, fix and install software remotely
 Internet or intranet access
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Computer Networks
Some benefits from networking includes:
• Fewer peripherals needed
• Increased communication capabilities
• Avoid file duplication and corruption
• Lower cost licensing
• Centralized administration
• Conserve resources
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Basic Concepts
Communications – activity associated with
distributing or exchanging information
Telecommunications – technology of communications
at a distance that permits information to be created
any where and used everywhere with little delay
Today it, involves
Data: digital and analog
Voice: spoken word
Video: telecommunication imaging
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Essentials for Communications
Must have a message
Message must have a transmitter/receiver
Message must have a medium
Message must be understood
Source System
Destination System
Source  Transmitter  Transmission  Receiver  Destination
Workstation/PC
Medium
Workstation/PC
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The elements that make up a network
Messages
Information that travels over
the medium
Devices
These are used to
communicate with one
another
Medium
This is how the devices are
connected together
Rules (Protocols)
Govern how messages flow
across network
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Network Concerns
Security
Unauthorized access to resources and data
Maintenance and support
Data backups
Managing hardware and software
Reviewing and maintaining security
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The Internet
Started in 1969 as U.S. Department of Defense
ARPANET
Plays key role in modern networking configurations
Root source of many PC network innovations
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Types of Networks
A computer network is identified by:
The type of media used to connect the devices
The type of networking devices used
How the resources are managed
How the network is organized
How the data is stored
The area it serves
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Network Models
Two basic network models:
Client/server
One or more computers designated as servers,
providing resources to network
Provides centralized control over network
security
Peer-to-peer
Network client computers act as both clients
and servers (peer servers)
Smaller networks
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Data Transmission
 Successful transmission of data depends on:
The quality of the signal being transmitted
Characteristics of the transmission medium
 Data rate – bits per second in data communications
 Bandwidth – bandwidth or signal is constrained by the
transmitter and the nature of the transmission in cycles per
second or hertz
 Noise – Average level of noise over the communication
path.
 Error rate – rate at which errors occur where error in 1 or
0 bit occurs
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Basic transmission medium concepts
Medium is the physical path between transmitter
and receiver in a data transmission system
Guided Medium: waves are guided along a solid
medium path (twisted pair, coaxial cable, and optical
fiber).
Unguided medium: waves are propagated through
the atmosphere and inner/outerspace (satellite,
laser, and wireless transmissions).
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Basic Signal Terminologies
Kilo
Mega
Giga
Tera
Peta
Exa
Zetta
Yotta
K
M
G
T
P
E
Z
Y
2^10
2^20
2^30
2^40
2^50
2^60
2^70
2^80
 Bit: binary digit, either 0 or 1
 Bit rate – a method for measuring data
transmission speed – bits per second
 Mbps – millions of bits per second (data speed;
measure of bandwidth = total information flow
over a given time) on a telecommunication
medium
 8 bits = 1 byte
 Mb – million bits (quantity of data)
 MB – million bytes (quantity of data)
 Gbps – Billion bits per second (data speed)
 Teraflops – trillion operations per second
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Network Interface Card (NIC)
Every computer and most devices (e.g. a network
printer) is connected to network through an NIC. In
most desktop computers, this is an Ethernet card
(10, 100 or 1000 Mbps) that is plugged into a slot on
the computer motherboard.
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Network Interface Card (NIC)
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Wired NIC Connection to Network
There are two types of Ethernet
cable.
Standard Ethernet cable is used to
connect a network adapter to a
hub/switch
Crossover cable is used to connect
two PCs
Common in 100Mbps and 1Gbps,
also available in 10Gbps
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Additional Functions of a NIC
Creates, sends, and receives frames
Frame: fundamental unit of data for network
transmission and reception
Deals with frame-level errors and incomplete or
unintelligible frame structures
Manages access to medium
Acts as gatekeeper (permits inbound
communications aimed only at its computer (or
broadcast) to pass through NIC and on to CPU)
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MAC Address
NIC has unique identifier, called Media Access
Control (MAC) address
Programmed into ROM chip
48-bit number, written as six two-digit
hexadecimal numbers
First part identifies manufacturer
Second part unique to each NIC
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Integrated NICs
On-board NICs: Most PC motherboard and laptop
computer manufacturers integrate the network
interface directly on to the motherboard
Might not meet a user’s needs
Wrong media
Wrong speed
Wrong architecture
Most on-board NICs are suitable for most users’
requirements
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Wireless Adapters
Include some or all of these components:
Indoor antenna and antenna cable
Software to enable adapter to work with
particular network environment
Diagnostic software to check installation or
troubleshoot
Installation software
Used with wireless access point to add wireless
devices to existing wired network