INTRODUCTION TO NETWORK chapter 1 - part 2

1. CHAPTER 1:
INTRODUCTION TO NETWORKING
Overview A brief overview about networking
Objective 1. To explain basic of
computer network
2. To describe and know
principle of
communication in
networking
3. To create LAN using
networking devices.

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1.1 Concept of Computer Network.
A network consists of TWO (2) or more computers connected together, and they can
communicate and share resources.
A network is a set of devices (often referred to as nodes) connected by communication
links. A node can be a computer, printer, or any other device capable of sending and/or
receiving data generated by other nodes on the network.
1.1.1 Advantages of Networking
a) Sharing Information
Example :
Data communication
b) Sharing Software and Hardware
Example:
Print document
c) Centralize administration and support
Example:
Internet-based, so everyone can access the same administrative or support
application from their PCs

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1.1.2 Network Types
a) Peer-to-Peer
- Peer-to-peer network is also called workgroup
- No hierarchy among computers  all are equal
- No administrator responsible for the network
i) Advantages of peer-to-peer networks:
• Low cost
• Simple to configure
• User has full accessibility of the computer
ii) Disadvantages of peer-to-peer networks
• Difficult to uphold security policy
• Difficult to handle uneven loading
• May have duplication in resources
iii) Where peer-to-peer network is appropriate
• 10 or less users
• No specialized services required
• Security is not an issue

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• Only limited growth in the foreseeable future
b) Client and Server
i) Client (Workstation)
 Computers that request network resources or services
ii) Server
 Computers that manage and provide network resources and
services to clients
 Usually have more processing power, memory and hard disk space
than clients
 Run Network Operating System that can manage not only data, but
also users, groups, security, and applications on the network
 Servers often have a more stringent requirement on its
performance and reliability
iii) Advantages of Client and Server
 Facilitate resource sharing – centrally administrate and control
 Facilitate system backup and improve fault tolerance
 Enhance security – only administrator can have access to Server
 Support more users – difficult to achieve with peer-to-peer networks
iv) Disadvantages of client/server networks
• High cost for Servers
• Need expert to configure the network
• Introduce a single point of failure to the system
1.1.3 Network Classification
a) Local Area Network (LAN)
• Small network, short distance
• A room, a floor, a building
• Limited by no. of computers and distance covered

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• Usually one kind of technology throughout the LAN
• Serve a department within an organization
Example:
• Network inside the Student Computer Room
• Network inside your home
b) Metropolitan Area Network (MAN)
• Consists of many local area networks linked together.
• Span the distance of just a few miles.
• Is network over a larger geographical area such as the provincial
government.
c) Wide Area Network (WAN)
• A network that uses long-range telecommunication links to connect 2 or
more LANs/computers housed in different places far apart.
• Towns, states, countries
• Examples:
• Network of our Campus
• Internet

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1.1.4 Network Topologies
Three basic type of network topology:
a) Bus Topology
• Simple and low-cost
• A single cable called a trunk (backbone, segment)
• Only one computer can send messages at a time
• Passive topology - computer only listen for, not regenerate data
• A continuous coaxial cable to which all the devices are attached.
• All nodes can detect all messages sent along the bus.
b) Ring Topology
• Nodes linked together to form a circle.
• A message sent out from one node is passed along to each node in between until
the target node receives the message.
• Typical way to send data:
• Token passing
• Only the computer who gets the token can send data

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• Disadvantages
• Difficult to add computers
• More expensive
• If one computer fails, whole network fails
c) Star Topology
• Each computer has a cable connected to a single point
• More cabling, hence higher cost
• All signals transmission through the hub; if down, entire network down
• Depending on the intelligence of hub, two or more computers may send message
at the same time
How to construct a network with Bus / Star Topology?
a) Bus Topology

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b) Star Topology
1.1.5 Comparison of Bus, Ring and Star Topology
Topology/structure Advantages Disadvantages
Bus structure -easy to install
-simply expandable
-short cable lengths
-net expansion limits
-by cable interrupt the
net precipitates
-complicated access
methods
Ring structure -large net expansion -complex error tracing
-high wiring expenditure
-When disturbances net
failure
Star structure -simple cross-linking
-simple extension
-high reliability
-high wiring expenditure
-net failure in case of
failure or overloading of
the hubs

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1.1.6 Standards for networking
a) Standard Definition
– Documented agreement
– Technical specifications/precise criteria
– Stipulates design or performance of particular product or service
b) Reason Why Standards are essential in the networking world
– Wide variety of hardware and software
• Ensures network design compatibility
– Standards define minimum acceptable performance
The Organization that set standards for networking consist of:-
i) ANSI (American National Standards Institute)
ii) EIA (Electronic Industries Alliance)
iii) TIA (Telecommunications Industry Association)
iv) IEEE (Institute of Electrical and Electronics Engineers)
v) ISO (International Organization for Standardization)
vi) ITU (International Telecommunication Union)
vii) ISOC (Internet Society)
viii) IANA (Internet Assigned Numbers Authority)
ix) ICANN (Internet Corporation for Assigned Names and Numbers)
ANSI (American National Standards Institute)
• ANSI (American National Standards Institute)
o 1000+ representatives from industry and government
o Determines standards for electronics industry and other fields
• Requests voluntarily compliance with standards
• Obtaining ANSI approval requires rigorous testing
• ANSI standards documents available online
EIA (Electronic Industries Alliance)
• Trade organization
o Representatives from United States electronics manufacturing firms

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• Sets standards for its members
• Helps write ANSI standards
• Lobbies for favorable computer and electronics industries legislation
TIA (Telecommunications Industry Association)
• Formed in 1988
o EIA subgroup merged with former United States
Telecommunications Suppliers Association (USTSA)
• Focus of TIA
o Standards for information technology, wireless, satellite, fiber optics,
and telephone equipment
• TIA/EIA 568-B Series
• Guidelines for installing network cable in commercial buildings
IEEE (Institute of Electrical and Electronics Engineers)
• International engineering professionals society
• Goal of IEEE
o Promote development and education in electrical engineering and
computer science fields
• Hosts symposia, conferences, and chapter meetings
• Maintains a standards board
• IEEE technical papers and standards
o Highly respected
ISO (International Organization for Standardization)
• Headquartered in Geneva, Switzerland
• Collection of standards organizations
o Representing 57 countries
• Goal of ISO
o Establish international technological standards to facilitate global
exchange of information and barrier free trade
o Widespread authority

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ITU (International Telecommunication Union)
• Specialized United Nations agency
• Regulates international telecommunications
• Provides developing countries with technical expertise and equipment
• Founded in 1865
o Joined United Nations in 1947
• Members from 191 countries
• Focus of ITU
• Global telecommunications issues
• Worldwide Internet services implementation
ISOC (Internet Society)
• Founded in 1992
• Professional membership society
• Establishes technical Internet standards
• Current ISOC concerns
o Rapid Internet growth
o Keeping Internet accessible
o Information security
o Stable Internet addressing services
o Open standards
• ISOC oversees groups with specific missions
o IAB (Internet Architecture Board)
 Technical advisory group
 Overseeing Internet’s design and management
• IETF (Internet Engineering Task Force)
o Sets Internet system communication standards
o Particularly protocol operation and interaction
o Anyone may submit standard proposal
o Elaborate review, testing, and approval processes

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IANA and ICANN
• IP (Internet Protocol) address
– Address identifying computers in TCP/IP based (Internet) networks
– Reliance on centralized management authorities
• IP address management history
– Initially: IANA (Internet Assigned Numbers Authority)
– 1997: Three RIRs (Regional Internet Registries)
• ARIN (American Registry for Internet Numbers)
• APNIC (Asia Pacific Network Information Centre)
• RIPE (Réseaux IP Européens)
– Late 1990s: ICANN (Internet Corporation for Assigned Names and
Numbers)
• Private nonprofit corporation
• Remains responsible for IP addressing and domain name
management
• IANA performs system administration
• Users and business obtain IP addresses from ISP (Internet service provider)
1.2 Principle of Communication in Networking
1.2.1 Component
Basic Elements /Components of Data Communication:-
a) Sender
b) Receiver
c) Medium
d) Message
e) Protocol

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1.2.2 Communication Devices
The communication devices divides into two categories:-
a) Wired
-Wired communication involve Data Terminal Equipment (DTE) and Data
Communication Equipment (DCE)
DTE (Data Terminal Equipment)
• Transmits and receives data; Examples: Desktop computer, Printer
DCE (Data Communications Equipment)
• Coupled to transmission medium; Examples: Router, Modem
b) Wireless
A wireless network is defined as a network protocol that enables online content
to be viewed and accessed via wireless devices such as cell phones, laptops and
handheld devices. The Example of Wireless network is Bluetooth, GPRS, and 3G
and so on.
Bluetooth
Bluetooth is a simple type of wireless networking that allows the formation of a
small network with up to eight devices being connected at once.

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General Packet Radio Service (GPRS)
 Introduces packet data transmission
 It uses radio spectrum
3G
 A telecommunication hardware standards and general Technology for mobile
networking
 Services – wide-area wireless voice Telephone, video calls, and broadband
wireless, data all in a mobile environment
1.2.3 Basic Data Transmission Concept
a) Analog and Digital Signaling
To be transmitted, data must be transformed to electromagnetic signals. Data
can be analog or digital. The term analog data refers to information that is
continuous; digital data refers to information that has discrete states. Analog
data take on continuous values. Digital data take on discrete values.
a. Analog Signal
i. Analog signals can have an infinite number of values in a range.
b. Digital Signal
i. Digital signals can have only a limited number of values.

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b) Data Modulation
Modulation is the process of conveying a message signal, for example a digital bit
stream or an analog audio signal, inside another signal that can be physically
transmitted.
c) Simplex , Half Duplex and Full Duplex
There are three communication modes which is Simplex , Half Duplex and Full
Duplex.
Simplex Communication
Only One-way communication is possible.
Examples : TV, Radio
Half – Duplex
Two-way communication is possible, but not simultaneously.
Example – Walky Talky.

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Full – Duplex
Two-way simultaneous communication is possible.
Example – Telephone System.
d) Multiplexing
Multiplexing (also known as muxing) is a process where multiple analog message
signals or digital data streams are combined into one signal over a shared medium.
e) Point-to-Point Transmission
Point-to-point refers to a connection restricted to two endpoints that sometimes
referred as P2P that has those criteria:
 direct link
 only 2 devices share link
f) Broadcast Transmission
Broadcasting is the distribution of audio and video content to a dispersed audience
via radio, television, or other. Receiving parties may include the general public or a
relatively large subset of thereof. It could also be for purposes of private recreation,
non-commercial exchange of messages, experimentation, self-training, and
emergency communication such as amateur radio (Ham) and amateur television.

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g) Bluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data
over short distances (using short wavelength radio transmissions in the ISM band
from 2400-2480 MHz) from fixed and mobile devices, creating personal area
networks (PANs) with high levels of security. Created by telecoms vendor Ericsson
in 1994,[1]
it was originally conceived as a wireless alternative to RS-232 data
cables. It can connect several devices, overcoming problems of synchronization.
h) Throughput
In communication networks, such as Ethernet or packet radio, throughput or
network throughput is the average rate of successful message delivery over a
communication channel. This data may be delivered over a physical or logical link,
or pass through a certain network node. The throughput is usually measured in bits
per second (bit/s or bps), and sometimes in data packets per second or data
packets per time slot.
i) Bandwidth
Bandwidth is a bit rate measure of available or consumed data communication
resources expressed in bits/second or multiples of it (kilobits/s, megabits/s etc.)
1.2.4 The Common Transmission Flaws that Affecting Data Signal
a) Noise
In communication systems, the noise is an error or undesired random
disturbance of a useful information signal, introduced before or after the
detector and decoder.
The noise is a summation of unwanted or disturbing energy from natural and
sometimes man-made sources.
Noise is, however, typically distinguished from interference, (e.g. cross-talk,
deliberate jamming or other unwanted electromagnetic interference from
specific transmitters)

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b) Attenuation
 Happen where signal strength falls off with distance
 Depends on medium
 Received signal strength must be:
o Strong enough to be detected
o Sufficiently higher than noise to receive without error
 So increase strength using amplifiers/repeaters
c) Latency
In a network, latency, a synonym for delay, is an expression of how much time
it takes for a packet of data to get from one designated point to another. In
some usages, latency is measured by sending a packet that is returned to the
sender and the round-trip time is considered the latency.
1.2.5 Rules of Network Communication
Network communication considers the following item in order to determine
transmission type for wired and wireless transmission.
Five basic properties of both the physical and wireless links:
a) Type of signal communicated (analog or digital).
b) The speed at which the signal is transmitted (how fast the data travels).
c) The type of data movement allowed on the channel (one-way, two-way
taking turns, two-way simultaneously).
d) The method used to transport the data (asynchronous or synchronous
transmission).
e) Single channel (baseband) and multichannel (broadband) transmission.
1.2.6 How Signal Transmit From a Host to Destination in Network
Transmission technology refers to whether digital or analogue transmission is
Used. Most modern communication networks, in particular computer
communication networks, use digital transmission technology. However, there are

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many communication networks in operation that use analogue transmission
technology. Those networks provide the plain old telephone service
(POTS) as well as allow computers to interconnect using modem technology
which converts the digital data signal of computers into an analogue signal that
can be transmitted across an analogue telephone network.
A second aspect of transmission technology is whether networks are point-to-
point or broadcast networks. Point-to-point networks connect any two network
nodes, such as computers, telephone apparatus, switches, routers, or hubs with a
physical connection. This physical connection can be based on copper, fibre, or
radio links. To go from source to destination, data will be routed along a
path that can involve one or more intermediate machines. Broadcast networks
have a single communication channel that is shared by all network nodes.
Communication takes place by one node sending data and all or a group of nodes
receiving the data. In the first case we talk about broadcasting, in the latter about
multicasting.
In order to transmit data from source to destination, point-to-point networks
use two different transmission options. The first option establishes a dedicated
route between source and destination along which the information flows. This
route is made up of dedicated physical links, which are used solely by the
communication service in question. This transmission option is called circuit
switching. On the other hand, a logical connection can be established along which
the information, in form of packets of data, is transmitted. The logical connection
can either use a physical connection, which is shared with others, or many
different physical connections are used depending on certain circumstances. This
transmission option is called packet switching. Packet switching uses two
transmission services, connection-oriented and connectionless transmission.
Information transmission in broadcast networks would be neither circuit nor packet
switched since there is no connection between two communicating parties
necessary. Examples of broadcast networks are cable and satellite television or
CB radio communication.

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1.3 LAN Using Networking Devices
1.3.1 LAN Hardware
a) Hub
A common connection point for devices in a network. Hubs are
commonly used to connect segments of a LAN. A 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.
b) Switches
A device that receives packets from its input link, and then sorts them
and transmits them over the proper link that connects to the node
addressed. Switch function and physical quite similar to Hub Function. The
only differences between Hub and Switch are the HUB copies the packets
to the other ports, so that all segments of the LAN can see all packets.
While a SWITCH switches direct connections between the attached
devices. So a switch is an intelligent HUB, who recognise over which port
which device is connected.
c) Routers
A device that forwards data packets along networks.
A router is connected to at least two networks, commonly two LANs or
WANs or a LAN and its ISP’s network (Internet Service Provider).
Routers are located at gateways, the places where two or more networks
connect.
d) Bridge
A link between two networks that have identical rules of communication.

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e) Wireless Access Point
A simple Wireless LAN is a local network with an ACCESS POINT for
WLAN adapter (network interface cards with antenna), which is attached to
the computer or inserted.
AP Short for Access Point, a hardware device or a computer's software
that acts as a communication hub for users of a wireless device to connect
to a wired LAN. APs are important for providing heightened wireless
security and for extending the physical range of service a wireless user has
access to.
f) Mobile based station
The base station subsystem (BSS) is the section of a traditional
cellular telephone network which is responsible for handling traffic and
signaling between a mobile phone and the network switching subsystem.

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The BSS carries out transcoding of speech channels, allocation of radio
channels to mobile phones, paging, transmission and reception over the air
interface and many other tasks related to the radio network.
The base transceiver station, or BTS, contains the equipment for
transmitting and receiving radio signals (transceivers), antennas, and
equipment for encrypting and decrypting communications with the base
station controller (BSC). The functions of a BTS vary depending on the
cellular technology used and the cellular telephone provider. There are
vendors in which the BTS is a plain transceiver which receives information
from the MS (mobile station) through the Um (air interface) and then
converts it to a TDM (PCM) based interface, the Abis interface, and sends
it towards the BSC. There are vendors which build their BTSs so the
information is preprocessed, target cell lists are generated and even
intracell handover (HO) can be fully handled. The advantage in this case is
less load on the expensive Abis interface.
1.3.2 Types of Network Interface Card
Network interface cards, referred to as NICs, are PC integrate cards that give inter-
networking capabilities for a particular computing solution. There are many types of
NICs that are utilized in changeable situations. The biggest variation between cards is
depending upon their connective medium and speed capabilities. To a lesser extent,
NICs can be distinguished by their type of connectivity to PC. There are three main
areas of the physical NIC experience:-
 Bus Types
The bus type, that is, the protocol for interfacing with the PC, of an NIC can
affect the performance of the computer or server. Most common type NIC bus
type is ISA, EISA and PCI.
 Supported Media Types
Media consideration is an important factor in using and NIC; it may support
twisted-pair, 10Base2, fiber-optic, or a combination of the above.
 Advanced Features

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a) PCI NIC
PCIe NIC
PCI – Clearly the dominant bus type for NICs and is rapidly becoming the only
interface option for new PCs. PCI is preferred for faster data transfer rates,
and normally clocks in at about 33MHz. PCI NIC utilized often utilized in home
or small office setting. As name implies, they are able of speeds up to 10 or
100 megabits per second, not to be confused with megabytes per second.
These cards generally attach to PC using a PCI, PCIe or ISA motherboard
interface slot.
b) PCMCIA Adapter
PCMCIA stands for Personal Computer Memory Card International
Association, the group of companies that defined the standard. To recognized
increased scope beyond memory, and to aid in marketing, the association
acquired the rights to the simpler term "PC Card" from IBM. This was the name
of the standard from version 2 of the specification onwards. These cards are
used for wireless networks, modems, and other functions in notebook PCs.The
PCMCIA was dissolved in 2009, and all of its activities are now managed by

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the USB Implementer's Forum, according to the PCMCIA website.[2]
Another name for PCMCIA or PC Card is CardBus, the 32-bit version of the
PCMCIA PC Card standard. In addition to supporting a wider bus (32 bits
instead of 16 bits), CardBus also supports bus mastering and operation
speeds up to 33 MHz.
USB (universal serial bus) port
 Two USB standards
o Difference: speed
o USB 1.1: transfer rate of 12 Mbps
o USB 2.0: transfer rate of 480 Mbps
 Future
o USB 3.0 (SuperSpeed USB)
o Transfer rate: 4.8 Gbps
FireWire
 Firstly introduce by Apple Computer (1980s)
 Upgrade using IEEE 1394 standard (1995) for other computers.
 Traditional Firewire connection: 400 Mbps (max)
 Newer version: 3 Gbps
 Connects most peripheral types
 Connects small network
o Two or more computers using bus topology
• FireWire-connected peripherals
 Similar to USB- and PCMCIA-connected peripherals
o Simple installation
o Supported by most modern operating systems
 Two connector varieties: 4-pin and 6-pin
USB NIC

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 6-pin connector
o Two pins supply power
o Interconnect computers
c) Compact Flash NIC
 Designed by CompactFlash Association (CFA)
o Ultrasmall
o Removable data and input/output device
 Latest standard: 4.0
o Data transfer rate: 133 Mbps
 Uses
o Connects devices too small for PCMCIA slots
o Wireless connections
d) On- Board NIC
 Connect device directly to motherboard
Compact Flash NIC
FireWire connectors (4-pin and 6-pin)

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o On-board ports: mouse, keyboard
 New computers, laptops
o Use onboard NICs integrated into motherboard
 Advantages
o Saves space
o Frees expansion slots
e) Wireless NIC
Wireless NICs give similar networking capabilities as wired counterparts,
though they have their own transfer capabilities. Speeds of 54 Mb/s are usually
available to wireless NICs without teaming some NICs together to mix
bandwidths. These NICs, though give for wireless networking that permits for
freedom in PC topology and installation.
1.3.3 Built a simple peer-to-peer network
Refer Labwork
1.3.4 Built a simple LAN using two host and switch
Refer Labwork
1.3.5 Map Network drive to share file
Refer Labwork
1.3.6 Install and configure a network printer in a simple LAN
Refer Labwork
1.3.7 Define VLAN
VLANs stand for virtual local area networks. It logically separate networks
within networks, means that it groups ports into broadcast domain.

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1.3.8 Identify the characteristic of VLAN
 Broadcast domain (subnet)
o Port combination making a Layer 2 segment
 Ports rely on layer 2 device to forward broadcast frames
 Collision domain
o Remember, switches prevent collisions
o Each device is on a separate collision domain
VLAN AND TRUNKING
1.3.9 Describe the advantages of creating VLANs in networks
 Advantage of VLANs
o Flexible
 Ports from multiple switches or segments
 Use any end node type
o Reasons for using VLAN
 Separating user groups who need special security
 Isolating connections with heavy traffic

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 Identifying priority device groups
 Grouping legacy protocol devices
1.3.10 Create VLANs in network
Refer Labwork