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LAB 3 DKT

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1

PPK KOMPUTER & PERHUBUNGAN




Universiti Malaysia Perlis







DKT224 DATA COMMUNICATION & NETWORK






LAB3



NETWORK SET
-
UP












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Lab 3: Network Set
-
up



Objectives


1. To learn basics of Local Area Network (LAN)

2. To learn procedure to make Unshi
elded Twisted
-
Pair (UTP) cable

3. To learn the configuration and setting
-
up Ethernet Network Interface Card (NIC)

4. To learn the procedure to test and verify network connectivity using ping and ftp.



Background


What Is a LAN?


A
LAN
is a high
-
speed data

network that covers a relatively small geographic area. It
typically connects workstations, personal computers, printers, servers, and other devices.
LANs offer computer users many advantages, including shared access to devices and
applications, file exch
ange between connected users, and communication between users
via electronic mail and other applications.


LAN Protocols and the OSI Reference Model


LAN protocols function at the lowest two layers of the OSI reference model i.e. between
the physical layer

and the data link layer. Figure 1 illustrates how several popular LAN
protocols map to the OSI reference model.



Figure 1
:
Popular LAN Protocols Mapped to the OSI Reference Model






Network Topologies

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Some of the most common topologies in use today i
nclude:


Bus
-

Each node is daisy
-
chained (connected one right after the other) along the same
backbone, similar to Christmas lights. Information sent from a node travels along the
backbone until it reaches its destination node. Each end of a bus network m
ust be
terminated with a resistor to keep the signal that is sent by a node across the network
from bouncing back when it reaches the end of the cable.




Figure 2:
Bus network topology


Ring
-

Like a bus network, rings have the nodes daisy
-
chained. The
difference is that
the end of the network comes back around to the first node, creating a complete circuit. In
a ring network, each node takes a turn sending and receiving information through the use
of a token. The token, along with any data, is sent from

the first node to the second node,
which extracts the data addressed to it and adds any data it wishes to send. Then, the
second node passes the token and data to the third node, and so on until it comes back
around to the first node again. Only the node
with the token is allowed to send data. All
other nodes must wait for the token to come to them.



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Figure 3:
Ring network topology


Star
-

In a star network, each node is connected to a central device called a
hub
. The
hub takes a signal that comes from

any node and passes it along to all the other nodes in
the network. A hub does not perform any type of filtering or routing of the data. It is
simply a junction that joins all the different nodes together.


Star bus
-

Probably the most common network top
ology in use today, star bus
combines elements of the star and bus topologies to create a versatile network
environment. Nodes in particular areas are connected to hubs (creating stars), and the
hubs are connected together along the network backbone (like
a bus network). Quite
often, stars are nested within stars, as seen in the example in the next page.



Figure 4:
Star network topology





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LAN Transmission Methods


LAN data transmissions fall into three classifications: unicast, multicast, and broadcast.

In each type of transmission, a single packet is sent to one or more nodes. In a
unicast
transmission
, a single packet is sent from the source to a destination on a network. First,
the source node addresses the packet by using the address of the destinati
on node. The
package is then sent onto the network, and finally, the network passes the packet to its
destination. A
multicast transmission
consists of a single data packet that is copied and
sent to a specific subset of nodes on the network. First, the so
urce node addresses the
packet by using a multicast address. The packet is then sent into the network, which
makes copies of the packet and sends a copy to each node that is part of the multicast
address.

A
broadcast transmission
consists of a single data
packet that is copied and sent to all
nodes on the network. In these types of transmissions, the source node addresses the
packet by using the broadcast address. The packet is then sent on to the network, which
makes copies of the packet and sends a copy t
o every node on the network.



LAN Switch


Switches
are data link layer devices that, like bridges, enable multiple physical LAN
segments to be interconnected into a single larger network. Similar to bridges, switches
forward and flood traffic based on MAC

addresses. Any network device will create some
latency. Switches can use different forwarding techniques

two of these are store
-
and
-
forward switching and cut
-
through switching. In
store
-
and
-
forward switching
, an entire
frame must be received before it is
forwarded. This means that the latency through the
switch is relative to the frame size

the larger the frame size, the longer the delay
through the switch.

Cut
-
through switching
allows the switch to begin forwarding the frame when enough of
the frame is re
ceived to make a forwarding decision. This reduces the latency through the
switch. Store
-
and
-
forward switching gives the switch

the opportunity to evaluate the frame for errors before forwarding it. This capability to
not forward frames containing errors i
s one of the advantages of switches over hubs. Cut
-
through switching does not offer this advantage, so the switch might forward frames
containing errors. Many types of switches exist, including ATM switches, LAN switches,
and various types of WAN switches.

LAN switches
are used to interconnect multiple LAN segments. LAN switching provides
dedicated, collision
-
free communication between network devices, with support for
multiple simultaneous conversations. LAN switches are designed to switch data frames at
h
igh speeds.







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Ethernet Basics


Ethernet is a local area technology, with networks traditionally operating within a single
building, connecting devices in close proximity. At most, Ethernet devices could have
only a few hundred meters of cable between t
hem, making it impractical to connect
geographically dispersed locations. Modern advancements have increased these distances
considerably, allowing Ethernet networks to span tens of kilometers.


Ethernet Terminology


Ethernet follows a simple set of rules
that govern its basic operation. To better understand
these rules, it is important to understand the basics of Ethernet terminology.


Medium
-

Ethernet devices attach to a common medium that provides a path
along which the electronic signals will travel. H
istorically, this medium has been
coaxial copper cable, but today it is more commonly a twisted pair or fiber optic
cabling.


Segment
-

We refer to a single shared medium as an Ethernet segment.


Node
-

Devices that attach to that segment are stations or nodes.


Frame
-

The nodes communicate in short messages called frames, which are
variably sized chunks of information.


The

Ethernet protocol specifies a set of rules for constructing frames. There are explicit
minimum and maximum lengths for frames, and a set of required pieces of information
that must appear in the frame. Each frame must include, for example, both a destinat
ion
address and a source address, which identify the recipient and the sender of the message.
The address uniquely identifies the node, just as a name identifies a particular person. No
two Ethernet devices should ever have the same address.


Ethernet Medi
um


Since a signal on the Ethernet medium reaches every attached node, the destination
address is critical to identify the intended recipient of the frame.


Figure 5:
A small ethernet network


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For example, in the figure above, when
computer B

transmits to

printer C
,
computers
A

and
D

will still receive and examine the frame. However, when a station first receives a
frame, it checks the destination address to see if the frame is intended for itself. If it is
not, the station discards the frame without even
examining its contents.



CSMA/CD


The acronym CSMA/CD signifies carrier
-
sense multiple access with collision detection
and describes how the Ethernet protocol regulates communication among nodes. Ethernet
uses a process called CSMA/CD to communicate acros
s the network.


Under CSMA/CD, a node will not send out a packet unless the network is clear of traffic.
If two nodes send out packets at the same time, a collision occurs and the packets are lost.
Then both nodes wait a random amount of time and retransmi
t the packets. Any part of
the network where there is a possibility that packets from two or more nodes will
interfere with each other is considered to be part of the same collision domain. A network
with a large number of nodes on the same segment will of
ten have a lot of collisions and
therefore a large collision domain.


UTP Cable


EIA/TIA wiring standards were first published in 1991 and has been evolving ever since.
The EIA/TIA
-
568 standard defines the specification of the cable to be used as well as
s
ome installation rules. The latest version of the EIA/TIA standard is 568B, which
contains some minor enhancements to the original 1991 standard. The most popular is
Category 5, the highest
-
quality UTP cable. It is tested at 100 MHz, allowing it to run
hig
h
-
speed protocols such as 100 Mbps Fast Ethernet and FDDI. Category 5 cable also
uses either 22 or 24 AWG unshielded twisted pair wires with impedance of 100 ohms.


The IEEE demands rigid compliance of how the cable is installed with RJ
-
45 connector.
Other
wise, you will have high
-
speed data transmission problem
-

NEXT. NEXT is the
coupling of signals from one twisted pair to another. NEXT is undesired because it
represents unwanted spillover from one pair to other. The result is corrupted data or no
connect
ion at all.


Even you are using Cat 5 cable with 4 twisted pair wires, it doesn't mean that the cable is
100% compliant with EIA/TIA standard if it is not connected to RJ
-

45 in the way it
should be. The
Straight
-
through cable ("Patch cable")
connection s
hould be like
shown in figure 6:

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Figure 6:
Straight through cable connection


Here is the pin
-
out for
Crossover cable ("Uplink cable")
:



Figure 7:
Crossover cable


There is also another wiring standard
-

EIA/TIA
-
568A. Technically, there is no differen
t
between 568A and 568B in Ethernet applications. However, if Ethernet system combined
with phone system is being used, most of the people will prefer 568A standard due to the
fact that 568B may have backward compatibility problem with standard Universal
S
ervice Order Codes (USOC) hardware, which are commonly used in the telephone
infrastructure.


Figure 8:
568A and 568B Pin
-
out


Straight through cables
-

make both ends exactly the same, use only one of the two
color codes above for both ends of the cable.


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Crossover cables
-

make both ends different, one end with 568A and the other with
586B. Crossover cables have different ends, since they have the send and receive pairs
switched.


In the most general sense,

crossover cables

are used to

connect

like equip
ment, such as
two computers, or two hubs directly to each other.

Straight through cables
, on the
other hand are used to

connect a computer to a hub, router or a cable modem.

An
uplink port on a network device, such as switch or a router acts as a crossover
. In other
words, a straight through cable connected to an uplink port is the same as a crossover
cable connected to a regular port.


To further confuse consumers, some modern hubs/switches can automatically detect and
switch ports to accommodate either cr
ossover or straight
-
through cables. Although there
are 8 wires in an UTP cable, Ethernet only uses 4 of them (one pair for sending and one
pair for receiving information), the other 4 wires are actually wasted (or can be used for
another run, or other wiri
ng wonders)




Practical work


Component and equipment:
-


Item






Qty

1) Modular Plug Crimp Tool


1

2) UTP Category 5 Cable (6 feet)


5

3) RJ 45 Connector




10

4) Cable Tester & Battery



1

5) Switch (5 Ports)




1

6) Cutter





1

7) PC






3



Project Details

In this lab session, students are required to set
-
up a Local Area Network
(LAN) consists of 3 PC’s by following the procedures as in 5. This project
must be done in group.








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Task


1. Ethernet Unshielded Twisted Pair (UTP) Cable

Preparations

2 types of UTP cables:

• Straight
-
Through cables


T
-
586A standard (2 units)



T
-
586B standard (2 units)

• Crossed cables


(1 unit)

References: Appendix A
-

Patch Cable Assembly Instructions


2. Configuration and Setting
-
up Ethernet Network

Reference: Appendix B
-

Network Configuration


3. Connecting and testing connection between 2 PC’s using Crossed cable.

Connecting PC’s with switches.


4. Testing and verify network connectivity using ‘
ping
’ command for each cross cable
and straight cable.


ping <each_ip_address_in_group>
-
c4


*
-
c4 is an option to limit the ping command by 4 packets only


5.
By using straight cable, connect PC with the ‘lab network’
and verify connection using
ftp
command OR open Firefox and type at the address:


ftp://192.168.39.113

OR

ftp://192.168.39.119




Upon the completion of your project,


i. Each group must present your LAN to the lab instructor.

ii. Lab Discussion:
-

Write down a simple and b
rief discussion of what you have learnt from this
lab session.


Complete all the tasks in the given project.


Submit your report to your INSTRUCTOR. Do not copy other students work.

Make your own report.






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APPENDIX A:
Patch Cable Assembly Instructions

Patch Cable Assembly Instructions










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APPENDIX B: Network Configuration


1.

Before start network configuration, connect ALL three pc to the Ethernet switch and
switch on the Ethernet switch.


2. Next step, on your linu
x desktop environment:


a.

Right click on ‘Network connection’ on your upper right screen.

b.

Click ‘edit connection’.

c.

On ‘wired’ tab, click ‘add’ to setup a new wired connection.

d.

Rename your new connection as ‘wired connection LAN’ and disable ‘connect
automati
cally’.

e.

On ‘IPv4 Settings’ tab, change ‘method’ to ‘Link
-

Local Only’.

f.

Proceed with ‘apply’ button and then ‘close’ button.

g.

Left click on ‘network connection’ on your upper right screen and change to
‘wired connection LAN’.


3. Open Terminal <Application
s


Accessories


Terminal>


4. Type ‘ifconfig’ command to show an ip address for each pc.