This document provides information about various computer networking concepts and components. It discusses networking faceplates, cables, connectors, routers, switches, wireless access points and controllers. It also covers networking protocols like IP addressing and topics like file downloading, uploading and network troubleshooting. The document is meant as a guide for a practical computer networking lab session.

1. COMPUTER NETWORKS
PRACTICAL 1
TG/2017/233
W. W. M. S. KARUNASENA

2. Also known as wall plates or outlet covers, networking
faceplates are plastic, or metal plates used for Cat5
cable, Cat5e or Cat6 ethernet cable installation. They
organize and keep network cables out of reach, so are
ideal for use in residential or commercial settings.
Exercise 1
• Part 1
network diagram of computer lab
o Face plate (outlet)
o Network cable
Networking cables are networking hardware used to
connect one network device to other network devices or
to connect two or more computers to share printers,
scanners etc. Different types of network cables, such as
coaxial cable, optical fiber cable, and twisted pair cables,
are used depending on the network's physical layer,
topology, and size.

3. A simple device that physically links, couples, or
connects, two things together. A male connector has
pins that fit into the sockets, or receptacles, of a female
connector, as the connectors mate. A male connector
sometimes is referred to as a plug, and a female
connector as a jack.
A router is 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. Routers are located at gateways, the
places where two or more networks connect.
o Connector
• Part 2
network diagram of server room
o Router

4. Unshielded twisted pair (UTP) is a ubiquitous type of
copper cabling used in telephone wiring and local area
networks (LANs). There are five types of UTP cables --
identified with the prefix CAT, as in category -- each
supporting a different amount of bandwidth.
Shielded twisted pair (STP) cable was originally designed
by IBM for token ring networks that include two
individual wires covered with a foil shielding, which
prevents electromagnetic interference, thereby
transporting data faster.
Fiber optic cable is a high-speed data transmission
medium. It contains tiny glass or plastic filaments that
carry light beams. Digital data is transmitted through the
cable via rapid pulses of light. The receiving end of a fiber
optic transmission translates the light pulses into binary
values, which can be read by a computer.
o Switch
o UTP - Unshielded Twisted Pair
o STP - Shielded Twisted Pair
o Fiber cable
A network switch is a hardware device that channels
incoming data from multiple input ports to a specific
output port that will take it toward its intended
destination. It is a small device that transfers data
packets between multiple network devices such as
computers, routers, servers or other switches.

5. • Part 3
o IP address
An Internet Protocol address (IP address) is a logical numeric address that is assigned to every
single computer, printer, switch, router or any other device that is part of a TCP/IP-based
network.
The IP address is the core component on which the networking architecture is built; no
network exists without it. An IP address is a logical address that is used to uniquely identify
every node in the network. Because IP addresses are logical, they can change. They are like
addresses in a town or city because the IP address gives the network node an address so that
it can communicate with other nodes or networks, just like mail is sent to friends and
relatives.
The numerals in an IP address are divided into 2 parts:
▪ The network part specifies which networks this address belongs to and
▪ The host part further pinpoints the exact location.

6. o default gateway
A default gateway is a hardware node that facilitates smooth connections between networks.
Its primary use is to serve as an access point for outbound connections to other networks,
essentially allowing one computer to communicate with another computer on a different
network.
'Default' gateway simply refers to the fact that this node will be used by default unless a
different route is specified in a request. Perhaps the most common request is when a
computer seeks to access a webpage, which is sent through the default gateway before being
sent to the internet. However, it can also be used to connect devices on one subnet with
devices on another - the gateway acting as an intermediary.
o DNS server
A DNS server is a type of name server that manages, maintains and processes Internet domain
names and their associated records. In other words, a DNS server is the primary component
that implements the DNS (Domain Name System) protocol and provisions domain name
resolution services to Web hosts and clients on an IP-based network.
o Ping
A ping is a signal sent to a host that requests a response. It serves two primary purposes:
1. to check if the host is available and
2. to measure how long the response takes.
A ping request can be performed using a ping command, which is a standard command in
most command line interfaces. Several network utilities provide a ping feature, which allows
you to ping a server by simply entering the IP address or domain name. Most ping programs
send multiple pings and provide and average of the pings at the end.
o Download
Downloading is the transmission of a file from one computer system to another, usually
smaller computer system. From the Internet user's point-of-view, to download a file is to
request it from another computer (or from a Web page on another computer) and to receive
it.
o Upload
Uploading is the process of moving digital files such as photographs or documents from your computer
and placing them on to a central server so that someone else can retrieve them or to a website so
others can see them. For example, you might save photographs from your digital camera on to your
computer and upload them on to a social network such as Facebook, where you can allow friends and
family to see them.

7. A crimping tool is a device used to conjoin two pieces of
metal by deforming one or both in a way that causes
them to hold each other. The result of the tool's work is
called a crimp. A good example of crimping is the
process of affixing a connector to the end of a cable. For
instance, network cables and phone cables are created
using a crimping tool (shown below) to join the RJ-45
and RJ-11 connectors to both ends of either phone or
Cat 5 cable.
Exercise 2
o 5 port switches
o RJ45 connector
o UTP cable
o Crimping tool
A switch used to connect only five devices to a computer
network.
RJ45 is the most common type of connector for Ethernet
networking. It's like a phone jack, but slightly wider.
Ethernet cables are also sometimes referred to as RJ45
cables because each end of the Ethernet cable has an
RJ45 connector. Switch, hub, PC, router, firewall etc. are
used to interconnect different types of devices. RJ 45 is
the most well-known and popular connectivity type in
the IT world.
UTP cables are widely used in the computer and
telecommunications industry as Ethernet cables and
telephone wires. In an UTP cable, conductors which
form a single circuit are twisted around each other in
order to cancel out electromagnetic interference (EMI)
from external sources. Unshielded means no additional
shielding like meshes or aluminum foil, which add bulk,
are used. UTP cables are often groups of twisted pairs
grouped together with color coded insulators, the
number of which depends on the purpose.

8. o Toolkit
Exercise 3
o Dial-up
Advantages Disadvantages
Security Slow connection speed (max of 56Kbps)
Include inexpensive hardware Inconvenience
Ease of setup and use Telephone line will be tied up while
accessing the Internet
Widespread availability Can’t use phone and internet at same time
unless have multiple lines
o ADSL - Asymmetric Digital Subscriber Line
A single utility program, a set of software routines or a
complete integrated set of software utilities that are
used to develop and maintain applications and
databases. There are toolkits for developing almost
anything. See tool, developer's toolkit, library, class
library and CASE.
Dial-up refers to an Internet connection that is
established using a modem. The modem connects
the computer to standard phone lines, which
serve as the data transfer medium. When a user
initiates a dial-up connection, the modem dials a
phone number of an Internet Service Provider
(ISP) that is designated to receive dial-up calls. The
ISP then establishes the connection, which usually
takes about ten seconds and is accompanied by
several beeping a buzzing sound.
The ADSL (Asymmetric Digital Subscriber Line) is a type
of technology of digital data transmission and Internet
access, which consists of the transmission through
symmetrical pairs of telephone line copper. This is, a
method of accessing the Internet through the telephone
line (Telephone Network Switched, PSTN) that does not
prevent the regular use of the line for calls.

9. Advantages Disadvantages
This represents an advantage when installing
the service in homes and companies, since it
allows the autonomy of both services,
something impossible with the dialing
method.
It is not enough to have a copper wire
telephone connection to use the ADSL, since
this technology has a limit of 3km of line
length from the emission center.
It does not require new and extensive
investments or large works, because it takes
advantage of traditional copper wiring.
In countries where this material is expensive
or scarce, the service may not be as
economical as in others.
It offers much better speed / price ratio than
the dialing methods, which in addition to
occupying the telephone line are usually at 56
kps, while the ADSL can reach 4mbps (70
times faster).
The quality of the service is subject to the
quality of the cables, the distance from the
power station and fluctuations in the service
flow.
Since it uses telephone cables, each
subscriber receives an independent and non-
transferable service directly to his home or
office.
The fiber optic connections far exceed the
ADSL stability and speed.
o Dongle
Advantages Disadvantages
Data is more secured Access Speed Limits
It is handy Users are limited to a single interface
Dongles are universal There are no greater options
Easy Installation No Traffic Maintenance
o Leased line
A dongle is a USB device which allows users to access the
internet remotely via a 3G broadband connection. This
plug-in is also referred to as Internet Stick, USB modem,
USB, USB network adapter, and mobile broadband stick
in different countries. People who are looking for a
device which they can use to access the Internet from
any location, a dongle come in handy.
leased line is a dedicated internet line that handles both
data and voice. A leased line is a symmetric circuit,
meaning you can send or receive data quickly from one
location to another (this can include multiple locations).
With a leased line, there is a dedicated connection which
results in not having to share the bandwidth with
anyone else. Essentially, your connection is not shared
so speeds will not be impacted during peak times when
others are using the same ISP (Internet Service Provider)
to full capacity.

10. Advantages Disadvantages
Leased Lines are Available at Higher Speeds Limited range of services - Only Plain Leased
Line Service, Data cards support only up to 64
kbps, no support for N x 64 Kbps.
No Slow-Down at Peak Times From Operator point of view in case of Leased
Line Circuit different boxes from different
vendors so difficult to manage & control.
Faster Uploads No Centralized Monitoring or alarm or
performance monitoring. The solution to this
is MLLN.
More Reliable
o Wi-Fi router
Usage
▪ Can use for LAN connections which means you can communicate to other devices which are connected
to the same router.
▪ You can run Webserver in router and use that Web Server as centralized memory to share files. No
need of USB to share files between devices.
▪ Can connect smoke USB censor to your router and get the information about your Air pollution in your
deployed area daily.
o Wireless access point
Usage
▪ To extend the coverage area, multiple access points are used together under a Wireless LAN
Controller.
▪ In WLC-LWAPs setup, the WLC controls and manages all LWAPs.
A wireless router is a device that performs the functions
of a router and includes the functions of a wireless
access point. It is used to provide access to the Internet
or a private computer network. Depending on the
manufacturer and model, it can function in a wired local
area network, in a wireless-only LAN, or in a mixed wired
and wireless network.
A wireless access point (WAP) is a hardware device or
configured node on a local area network (LAN) that
allows wireless capable devices and wired networks to
connect through a wireless standard, including Wi-Fi or
Bluetooth. WAPs feature radio transmitters and
antennae, which facilitate connectivity between devices
and the Internet or a network.

11. ▪ A LWAP works as the bridge between the WLC and the end device.
▪ A standalone access point works in the wireless network exactly as the switch works in the wired
network.
▪ To control the unauthorized access, Access point uses authorization.
▪ Access point connects multiple wireless devices together in a single wireless network.
o Wireless controller
Usage
▪ Load balancing: Disabled by default, high-speed load balancing can be used to connect a user to
multiple access points for better coverage and data rates.
Discussion
• Improvements in ICT Lab design
o Since cable costs a lot of money, I expect cable-free technology to be more convenient.
Troubleshooting is also easier.
o Can upgrade to a mesh-based system for faster connectivity.
• Improvements in Server Room design
o A remote-control server room needs to be set up. because If the server down, it can be repaired very
quickly from anywhere.
• Extend wireless connectivity to hostels
o Difficulties
▪ The hostel has many Internet users. Therefore, the speed of the connection is slightly reduced.
▪ Given that the hostel is located a short distance away, it is not easy to provide the connection.
o How to overcome
▪ can increase the range of the wireless connectivity using repeaters or range extenders.
▪ A series of individual nodes can be installed around the hostel. Then can access the internet without
interruption throughout the hostel.
A wireless LAN (or WLAN) controller is used in
combination with the Lightweight Access Point Protocol
(LWAPP) to manage light-weight access points in large
quantities by the network administrator or network
operations center. The wireless LAN controller is part of
the Data Plane within the Cisco Wireless Model. The
WLAN controller automatically handles the
configuration of wireless access-points.