Power Point Presentation on Computer Networking - Assignment on Networking Module of QA - Software Tester Course - Provided by Shift Education of Technology Fundamentals of Computer Networking - Rafael SA This presentation incorporates subjects such as TCP/IP, Networks Classification, OSI Model, DHCP, DNS Protocols and IPv4 and IPv6 Addressing schemes and more.

1. Fundamentals of Computer Networking
Shift Education of Technology - SSMB4
Instructor: Fathul Islam
Student: Rafael Silva Antunes

2. Topics
1. Computer Networking
2. Network Classifications
3. Topology (bus, ring, star, mesh)
4. Computer Peripherals Input Output
5. Network Components Peripherals
6. Internet Protocol terms
7. IP identification and command line tool
8. DNS – Human readable address
9. DHCP – Dynamic Host Control
10. Models and Standards – OSI + TCP.IP
11. References and suggested readings

3. Computer networking is a collection of computers or other devices linked and working simultaneously, with the purpose to
send/receive data, allowing communication channels to share resources and information.
Computer networking permits mobility, work remotely, and saving of digital space medium.
One example of a network is what is today known as Internet.
Internet is the largest known network of computers, each computer with its specifications and address. Internet can be called
network of networks and spawns all over the Globe.
Other networks smaller in scale but equally important are: Public Library Network (search book quick), Airport Terminal Screens
with flight information (arrivals and departures), POS – Points of Sale at retail stores, that credit our bank account instantly, also
done by a Banking Institution network.
1. Computer Networking Definition

4. Advantages
Reduced costs: fast
information
exchange, shared
group work, work
remotely.
share one internet
line service
Creativity,
Interactivity,
Cooperation
Security driven
design,
controlled access,
resource
management
Performance
Adjustment, "QoS"
Leisure and
recreational activity
Disadvantages
Extra costs: the
internet service, the
equipment,
specialized software
constant power line
required ( watts/per
hour)
Is required a certified
network
administrator for
supervision
Security Risk,
sensible data
Compatibility
requirements
Exposure and socio-
cultural aspects
Computer Networks facilitate a great number of activities at the expense of equipment costs, and constant qualified human
supervision for certain cases. Many Companies have always someone qualified to configure and pinpoint errors when network or
computer doesn't work.
Noteworthy computer networks benefits are: Workgroups, shared access data, staff communication and management,
Centralized points of storage, Delivery of services and products remotely. Centralization of services, or Long distance
communication.
Computer networks are important for the circulation of computerized data but many concerns or aspects need to be addressed
before deploying a group of computers, I will enumerate a few positive and negative aspects of computer networking:
1.2 Computer Networking Advantages and Disadvantages

5. Local area network (LAN) The computers are geographically close together (same network segment).
Wide area network (WAN) The computers are farther apart and are connected by telephone lines or radio waves.
Metropolitan area network (MAN) A data network designed for a town or city.
Personal area network (PAN) Personal Device Network
virtual private network (VPN) A private network able to cross WAN with special aid of software to encrypt communication.
Campus area network (CAN) College/University Network
Storage area network (SAN) A high-speed network of storage devices.
In layman's terms a regular user to go online at the public library, uses Public Library LAN, that uses a ISP (Internet Service
Provider) leased line, to get access to WAN, this ISP in turn connects various LAN's within a city, this extensive geographical
area ranging from 2 to 100 miles can be called WAN, communication is done over an extensive geographical area.
The Public Library has a LAN that is part of MAN - Metropolitan area network that has access to the WAN.
So WAN encompasses MAN that encompasses LAN, thus WAN > MAN > LAN.
2.0 NetworkClassifications
Computer Network classification names come from their functions, logical or physical
topology, scale, software architecture and configuration.
The fundamental ones is LAN, MAN and WAN in ascending order of real scale.

6. 2.1 NetworkClassifications -Local Area Network
Lan – the acronym stands for Local Area Network. LAN is a
group of computers located in the same room, on the same
floor or in the same building that are connected to form a
single network as to share resources such as disk drives,
printers, data, CPU, fax/modem, application, etc.
LAN is generally limited to specific geographical area less than 2
K.M., supporting high speed networks.
ADVANTAGES OF LAN:
It allows sharing of expensive resources such as Laser printers,
software and mass storage devices among a number of
computers, one single leased line.
LAN allows for highspeed exchange of essential information, It
contributes to increased productivity.
3. Security Risks are restricted
DISADVANTAGES OF LAN:
LAN installation needs careful study closely in the context of its
proposed contribution to the long range interest of the
organization.
LAN Office

7. 2.2 NetworkClassifications -MetropolitanArea Network
Man - short for Metropolitan area networks are large computer networks usually spanning a city, they typically use wireless or wired connections
to link their sites.
MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. Metropolitan area networks
can span up to 100 km, considering other network classifications MAN network size falls between a WAN and LAN.
MAN networks provide Internet for LANs in a metropolitan region, and connect them to Wider Area Networks like the Internet.
MAN network size can range in area of between 2 km to 100 km distance of diameter.
ADVANTAGES OF MAN:
Cover a good range of Miles, capable of including a number of blocks, or an entire city.
High-Bandwidth @ High-rates
DISADVANTAGES OF MAN:
Security Concerns due to Public Lines carrying High Volume of Public Traffic
High number of cabling
Maintenance Costs

8. 2.3 Network Classifications - Wide Area Network
Wan – short for Wide Area Network is a network system connecting cities,
countries or continents (Regions), a network that uses routers and public
communications links. The largest and most wellknown example of a WAN is
the Internet.
WANs are used to connect LANs and other types of networks together, so
that users and computers in one location can communicate with users and
computers in other locations.
Many WANs are built for one particular organization and are private. Others,
built by Internet service providers, provide connections from an
organization's LAN to the Internet.
WANs are often built using leased lines.
Advantages of WAN:
Covers large geographical area, allowing long distance networking
Supports global markets and businesses
Connects large masses of Hosts
Disadvantages of WAN:
High Equipment and maintenance Costs
Security Concerns due to High Volume Traffic
Many dependent networks
Low data rates due to latency and hop levels.
Picture at right – WAN Network of 3 Routers, connecting 3 Buildings, thousands of
Miles apart.

9. 3. Topology – Bus, Ring,Starand Mesh
Topology of a network is the position layout of components/devices in a network, there is two parts in topology, the
physical topology refers to geographical position of the network components and the logical topology handles data
flow within a network, regardless of its physical design.
The goal of topology is to find the most economical and efficient connectivity while providing QoS and a reliable
network system.
The selection of network topology cannot be done isolated, certain criteria should be studied before, for a correct
strategic installation.
In the picture below some common topologies
layouts. Green dots represent network nodes.

10. 3.1 Topology – Bus
In the bus network topology, every workstation is connected to a main cable called the bus. Each
workstation is directly connected to every other workstation in the network.
Advantages
• Very easy to connect a computer or peripheral to a linear bus
• Requires less cable length than a star topology resulting in lower costs
• It works well for small networks.
• Does not use a device to route traffic.
Disadvantages
• Entire network shuts down if there is a break in the main cable or one of the T connectors break.
• Large amount of packet collisions on the network, which results in high amounts of packet loss.
• High traffic, broadcasts on a single line.

11. 3.2 Topology – Star
On the Star network topology, there is a central computer or server to which all the workstations are directly connected.
Every workstation is indirectly connected to every other through the central computer.
Data on a star network passes through the hub, switch, or router before continuing to its destination. The hub, switch, or
router manages and controls all functions of the network.
Advantages
• If one node or its connection breaks it doesn’t affect the other computers and their connections.
• Devices can be added or removed without disturbing the network
• It's a 2-way communication
Disadvantages
• An expensive network layout to install because of the amount of cables needed
• The central hub is a single point of failure for the network

12. 3.3 Topology – Ring
On the ring network topology, each computer is connected to two other computers forming a
circle where network messages flow in a unidirectional path through the computers until
they reach the desired destination. If one computer is removed network doesn't work.
Advantages
• Very organized
• Reduced chance of traffic collision
• Traffic flows in one direction at High Speed
• No need of a HUB/Switch/Router to route traffic
Disadvantages
• Low fault tolerance
• Not scalable, hard to add new workstations or entities
• All workstations or entities have be operating for the flow of messages

13. 3.4 Topology – Mesh
On the Mesh network topology, most of the devices are connected to every other device.
There is two types of mesh topology: full and partial mesh. At logical level if one node is
broken transmission is still possible via an alternate route, this justifies its use in WAN networks.
This topology uses a routing technique for transmission and identification of receivers using a
process called self-healing algorithm. The Internet is considered a Mesh Topology network.
Advantages
• Scalable, Large Bandwidth
• High Fault tolerant
• Reliability
Disadvantages
• Complex cabling
• Skilled Administration
• Expensive installation and maintenance
http://www.networking-basics.net/mesh-topology/ - Date last accessed: March 9, 2017

14. 4. Computer Peripherals- InputOutput(I/O)
Computer peripherals is hardware devices that have I/O function for the computer or a network.
There is 3 types: INPUT only, OUTPUT only and I/O DEVICES the latter providing both. I/O stands for input output of data via
an interface using cables plugged to ports, this stream of data can also be done wirelessly. Here is some examples:
-A peripheral is "an ancillary device used to put information into and get information out of the computer".[1]
• Mouse ( input ) inputs cursor position
• Keyboard (input) input keystrokes of user
• Printer (output) provide hard copies
• Monitor (output) display image to user
• Microwave (I/O device) Does Popcorn and more
In the picture at left a surveillance system with peripheral devices
with I/O functions networking.
4 POE (power over ethernet) IP cameras (input device) connected
to a switch (I/O device), one NVR (network video recorder) I/O
device receiving image of cameras through the switch, also
connected to a Router(I/O Device) accessing Internet. Video
Surveillance can be monitored on a display (Output device)
remotely or locally.
Picture: http://www.ipworld.vn/en/giai-phap/detail/surveillance-camera-solution-149 - Date last accessed: March 9, 2017
[1] Laplante, Philip A. Dictionary of Computer Science, Engineering and Technology. ISBN 0-8493-2691-5 Date last accessed: March 9, 2017
http://www.pecktechdesigns.com/Introduction/IntroductionToPeripheralsAndConnections.asp Date last accessed: March 10, 2017

15. 1. NIC Network Interface card ( Internal I/O Device)
2. HUB
3. Switch
4. Bridge
5. Repeater
6. Router
5. NetworkComponents Peripherals
There exists hardware considered a network peripherals to assist network connectivity and communication here is a list of
common ones their characteristics and features:
1. NIC – short for network interface card – is an internal component of a computer essential for the transmission of data, the
main interface between the cable and the CPU responsible to translate electrical signal into bytes. Has one unique address and
direct access to computer memory, performs tasks on the Physical Layer of the OSI Model.
2. HUB – is a ethernet network device capable of joining various computers in a network segment, by copying the signal to other
ports. HUB handles the data type known as frame, the frame is passed along or "broadcasted" to the other ports. It doesn't
matter (doesn't know...) that the frame is destined for one port.
3. Switch – is a network device a device that filters and forwards packets between LAN segments. Switches operate at the data
link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and therefore support any packet
protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched
Ethernet LANs. [2]
[2] http://www.webopedia.com/DidYouKnow/Hardware_Software/router_switch_hub.asp - Date last accessed: March 9, 2017
NIC
HUB SWITCH

16. 5.1 Network Components Peripherals
4. Bridge – A network bridge is a computer networking device that creates a single aggregate network from multiple
communication networks or network segments. This function is called network bridging. Bridging is distinct from routing, which
allows multiple different networks to communicate independently while remaining separate.[1] Bridges operate at Layer 2 Level of
the OSI Model.
6. Router – routers are an extremely feature rich network component, router's job, as its name implies, is to route packets to
other networks, these devices are located at gateways, a point where two or more networks connect. Using headers and
forwarding tables, routers determine the best path for forwarding the packets. Routers use protocols such as ICMP to
communicate with each other and configure the best route between any two hosts. Routers typically include a 4 - 8 port
Ethernet switch (or hub) and a Network Address Translator (NAT), including a Dynamic Host Configuration Protocol (DHCP)
server, Domain Name Service (DNS) proxy server and a hardware or software-based firewall to protect the LAN from malicious
intrusion from the Internet.[2]
5. Repeater – these devices receive and amplify signal, in order to join two or more segments of networks, due signal noise,
attenuation, and strength this is optimal choice to increase network diameter.
[2] http://www.webopedia.com/DidYouKnow/Hardware_Software/router_switch_hub.asp - Date last accessed: March 9, 2017
http://www.utepo.net/tech_details.asp?id=379 - Date last accessed: March 10, 2017
Bridge – Netgear WNCE2001 Repeater - UTP7101ER
Router

17. 6. InternetProtocol Terms
Internet - is a massive network of networks, a networking infrastructure.
Internet refers to network of networks. In this network each computer is recognized by a
globally unique address known as IP address. A special computer DNS (Domain Name
Server) is used to give name to the IP Address so that user can locate a computer by a
name. [1]
Intranet - is an internal or private network accessible by authorized individuals within an
organization, or a type of network whose access is restricted by users of a corporation.
[2] https://techterms.com/definition/protocol - Date last accessed: March 9, 2017
Protocol – in networking the term Protocol defines the format and order messages are
sent and received by entities of a network. Protocol is common set of rules and
instructions that each computer follows to communicate, there are different Protocols for
different goals.[2]
e.g. FTP, HTTP, SSH, SMTP, POP, IMAP, DHCP, etc. These are names of services that widely
used in networking, each with different functions for the network operability.
[1] www.tutorialspoint.com/internet_technologies/ - Date last accessed: March 9, 2017
IPv4 – stands for Internet Protocol version 4 a core Protocol adopted to give address to
devices in a network called IP Address this is represented by 4 Bytes using dot-decimal
notation, IPv4 uses 32-bit addresses which limits the address space to 4294967296 (2 to
the power of 32) addresses. IPv4 reserves special address blocks for private networks (~18
million addresses) and multicast addresses (~270 million addresses).

18. 6.2 Internet Protocol Terms
IP Address Classes – IPv4 uses hierarchical addressing scheme,
the address is 32-bits in length, is divided into two or three parts
[picture at right] network,sub-network and host, using quad-dotted
representation a single IP address can contain information about
the network, sub-network and the host. This scheme enables the IP
Address to be hierarchical where a network can have many sub-
networks which in turn can have many hosts.[1] IPV4 has 5 classes A,
B, C, D and E, being A,B,C used for commercial purposes excluding
private ip ranges, loopback ip and APIPA addresses.
ARP – stands for Address Resolution Protocol, is a telecommunication protocol used for
resolution of Internet layer addresses into link layer addresses, a critical function in
computer networks. ARP is used for mapping a network address (e.g. an IPv4 address) to
a physical address like an Ethernet address (also named a MAC address).
MAC – A media access control address (MAC address) of a computer is a unique identifier
assigned to network interfaces for communications at the data link layer of a network
segment. MAC addresses are used as a network address for most IEEE 802 network
technologies, including Ethernet and Wi-Fi. Logically, MAC addresses are used in the
media access control protocol sublayer of the OSI reference model.[2] This is a 48 Bit
address.
[1] https://www.tutorialspoint.com/ipv4/ipv4_addressing.htm - Date last accessed: March 9, 2017
[2] https://en.wikipedia.org/wiki/MAC_address - Date last accessed: March 10, 2017

19. 7. IP identification and command line tool
-What is/are the commands to find IP Address, Subnet Mask, Default
Gateway, MAC Address, in Windows and Mac Operating Systems ?
In Windows OS: go to command line and write ipconfig /all
step 1. Windows key + R and write cmd.exe press enter.
Step 2. Now at the command line prompt> digit "ipconfig /all"
Step 3. The program outputs on the screen all information
about your network adapters. Picture at right.
In Mac OS: Go to Terminal and digit ifconfig
step 1. Go To Applications [ shift + command + A ] go to
Utilities folder to find and open Terminal app.
Step 2. Using Terminal at the prompt$ enter "ifconfig"
verify results on the Screen. Picture at right.
http://www.emaculation.com/lib/exe/detail.php/image018.gif?id=appletalk_for_sheepshave - Date last accessed: March 10, 2017

20. 8. DNS – Humanreadable address
DNS - Domain Name System
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private
network.
Translates the names of network nodes (e.g. www.facebook.com) into network addresses (numerical IP Addresses).
By providing a worldwide, distributed directory service, the Domain Name System is an essential component of the functionality of the Internet, that has been in
use since 1985.
Address Resolution
Hosts on the Internet are usually known by names, e.g., www.example.com, not primarily by their IP address, which is used for routing and network interface
identification. The use of domain names requires translating, called resolving, them to addresses and vice versa. This is analogous to looking up a phone number in
a phone book using the recipient's name. The translation between addresses and domain names is performed by the Domain Name System (DNS), a hierarchical,
distributed naming system which allows for sub delegation of name spaces to other DNS servers.
The Internet maintains two principal namespaces, the domain name hierarchy and the Internet Protocol (IP) address spaces. The Domain Name System maintains
the domain name hierarchy and provides translation services between it and the address spaces. Internet name servers and a communication protocol implement
the Domain Name System.
A DNS name server is a server that stores the DNS records for a domain; a DNS name server responds with answers to queries against its database.
Every Network adapter has 2 or more Name Server Addresses associated to it, to perform DNS Request.
1. Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for assigning IP addresses (IP address space allocation), protocol parameter
assignment, domain name system management, and root server system management functions previously performed by IANA.
2. DNS is an important protocol operating at the heart of application layer of OSI Reference MODEL, a service that uses UDP, which is part of the TCP/IP stack, DNS
Servers operate/listen on Port 53.
3. Many Protocols operating at Application Layer Level Protocol make use of this Service before initiating communication examples are: FTP, EMAIL, HTTP, SSH, etc.

21. 8.1 DNS- Human readable address
- To find the DNS or Name Servers for your network adapter
In Windows OS: go to command line and write ipconfig /all
step 1. Windows key + R and write cmd.exe press enter. Step 2.
Now at the command line prompt> digit "ipconfig /all" Step 3.
Look for DNS Servers. . . adapters. Picture at right.
In Mac OS: Go to System Preferences > Internet &
Network section, click Network.
step 1. Select the network interface and click
Advanced...
step2. Click the [DNS tab] and check the values.
Picture at right.
https://www.howtogeek.com/howto/38793/how-to-switch-mac-os-x-to-use-opendns-or-google-dns/ - Date last accessed: March 10, 2017

22. 9. DHCP – DynamicHost Control
DHCP – stands for Dynamic Host Configuration Protocol (DHCP) and is network protocol to
automate Internet Protocol (IP) networks.
The DHCP protocol uses CLIENT/SERVER communication to initiate the lease transaction,
this is controlled by a DHCP server that dynamically distributes network configuration
parameters, such as IP addresses, for interfaces and services.
A Network component commonly found and used in Households is the basic Router
with DHCP server capabilities on the LAN and Wireless Lan, attributing different IP
addresses to each device to avoid network conflicts.
-In the absence of a DHCP server, each computer or other device (eg., a printer) on the
network needs to be statically (ie., manually) assigned an IP address.
ISP uses DHCP to attributed leased lines to clients also.
DHCP Transaction initiates at the client on Port 68[bootpc] with a dhcp request via UDP
reaching DHCP SERVER on Port 67 [bootps] returning with a frame dhcp ack to client on
Port 68[bootpc], with a success transaction client receives IP Address, Subnet Mask, DNS
Servers and Default Gateway and is ready to network.
How to configure you network adapter to receive automatic configuration from a DHCP ?
method 1: open a command prompt with elevated privileges and issue this 2 commands:
netsh interface ip set dns "Local Area Connection" dhcp
netsh interface ip set address "Local Area Connection" dhcp
Where "Local Area Connection" is the name of your connection in question...
Method 2: Open > Control PanelNetwork and InternetNetwork Connections > Select the corresponding Adapter (right
mouse button) Select Properties > Select [Internet Protocol version 4 ] and click Properties Box. - In the next window.box
select both options "Obtain IP Address Automatically" and "Obtain DNS server address automatically" hit OK and close
other boxes. GO REFRESH YOUR CONNECTION TO SEE THE RESULTS...

23. 10. ModelsandStandards– OSI + TCP.IP
OSI Model – stands for Open Systems Interconnection,
OSI/ISO is a conceptual or reference model, created by
International Organization for Standardization(OSI ) in 1986,
with the aim of developing a standard unified protocol,
therefore emerged the Open Systems Interconnection
Reference Model, that allow us to understand the concept of
an unified architecture structure.
OSI has 7 Layers: Physical Layer, Data Link Layer, Network
Layer, Transport Layer, Session Layer, Presentation Layer and
Application Layer each with specific communication functions
on respective protocols. OSI Model takes on a vertical
approach where each Layer Provides service to Upper Layer
and Request service of Lower Layers.
TCP/IP Model - TCP/IP Stack or Internet Protocol Suite network
model is a four-layer reference model ( Link Layer, the Internet
Layer, Application Layer, Transport Layer). All protocols that
belong to the TCP/IP protocol suite are located in the top
three layers of this model. This model was developed prior to
the OSI Model by Department of Defense in 1960's. This
Model is more oriented at the Internet and is a protocol
dependent model, and has an horizontal approach unlike OSI
which has a vertical approach.
The Layer concept in TCP/IP and OSI helps us understand the
action that occurs during communication from one computer
to another. Therefore, easy to identify issues and then
troubleshoot.

24. References and suggested readings
1. General Reference http://networkplanet88.blogspot.com/2013/07/a-comparison-of-network-models.html Date Last Accessed: 10 March, 2017
2. General Reference http://www.differencebetween.net/technology/internet/difference-between-osi-and-tcp-ip-model/ Date Last Accessed: 10 March, 2017
3. General Reference http://spu6sem.blogspot.com/2012/12/introduction-computer-networks.html Date Last Accessed: 10 March, 2017
4. General Reference http://www.webopedia.com/quick_ref/network-fundamentals-study-guide.html#define-network Date Last Accessed: 10 March, 2017
Suggested Readings
Linux Pocket Guide 1st Edition by Daniel J. Barrett - ISBN-13: 978-0596006280 ISBN-10: 0596006284 – Available on Amazon.com
Linux Administration: A Beginner's Guide, Fifth Edition 5th Edition by Wale Soyinka ISBN-13: 978-0071545884 ISBN-10: 0071545883 – Available on
Amazon.com
Timeline Internet Hall of Fame -http://internethalloffame.org/internet-history/timeline
Computer Networking Pictures - http://computer.howstuffworks.com/computer-networking-pictures.htm