ICS342-Lab4

gazecummingNetworking and Communications

Oct 26, 2013 (3 years and 11 months ago)

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LAB MANUAL

COMPUTER
NETWORK SYSTEMS



Department of Information and Computer Science

College of Computer Science and Engineering

King Fahd University of Petroleum and Minerals

2005

TABLE OF CONTENTS


LAB4

................................
................................
................................
................................
.....

1

Dynamic host configuration protocol


DHCP

................................
...........................

1

and

................................
................................
................................
................................
..........

1

network measurement

................................
................................
................................
........

1

4.

Objectives

................................
................................
................................
...............

1

4.1

Dynamic Host Configuration Protocol

................................
............................

1

4.1.1

Configure your computer

................................
................................
.............

1

4.1.2

Configure Windows 2003 as a DHCP Client

................................
...........

2

4.1.3

Configure Windows 2003 as a DHCP Server

................................
..........

2

4.1.4

Capture DHCP traffic

................................
................................
...................

5

4.2

Network Measurement

................................
................................
........................

8

4.2.1

Getting ready for measurement

................................
................................
..

8

4.2.2

Creating a Real
-
Time Performance Monitor chart

................................
..

9

4.2.3

Install the Network Monitor

................................
................................
.......

9

4.2.4

Configure the chart

................................
................................
........................

9

4.2.5

Generation of data and its representation

on the chart

........................

10

4.2.6

Summarizing performance data in a Performance Monitor report
....

10

4.2.7

Generating Alerts

................................
................................
.........................

11

4.2.8

Topology Diagrams

................................
................................
.....................

13

4.2.9

Cascade shared hubs

................................
................................
...................

14

4.2.10

Segmented LAN

................................
................................
...................

14

4.2.11

High
-
density Fast Ethernet Switched workgroup

..........................

14

4.2.12

Data
-
entry tables

................................
................................
...................

14

4.3

Analysis

................................
................................
................................
.................

17

4.4

References

................................
................................
................................
............

18





1


L AB
4

DYNAMIC HOST CONFIGU
RATION PROTOCOL


DHCP


AND

NETWORK MEASUREMENT

4.

Objectives



Configure Window
s 2003 as a DHCP Server



Capture and analyze DHCP traffic generated



Learn about different modes of network connections using hubs
and switches



Analyze the network based on different parameters

4.1

Dynamic Host Configuration Protocol

DHCP is a client/server prot
ocol that automatically provides an IP host with its IP
address and other related configuration information such as the subnet mask and default
gateway. RFCs 2131 and 2132 define DHCP as an Internet Engineering Task Force (IETF)
standard based on the Boot
Protocol (BOOTP), with which it shares many implementation
details. DHCP allows hosts to obtain all necessary TCP/IP configuration information from a
DHCP server.

4.1.1

Configure your computer

For this lab we will make all the lab computers as hosts on their re
spective network.

Thus at every computer modify the network configurations as follows:

1.

Setup the first computer in every network as a DHCP server and have the other
computers in the group point to it as DHCP clients. Thus computer 192.168.230.1


which wil
l be configured as DHCP server has static IP but all the clients get IP address


2


from the server.

2.

Make sure that the Instructor PC is not acting as a connectivity between our lab
network and the CCSE network. This is to make sure that our DHCP server does
not
provide IP address to the PC present in the CCSE network.


4.1.2

Configure
Windows 2003 as a DHCP Client

Start

Control⁐anel

Netw潲k C潮ne捴i潮s
. Right
-
click and select
Open
. Select
anyone of the
local area connections

and click. Click
Properties. Local Area

connection
properties window

appears.

Select
Internet Protocol (TCP/IP)

and click
Properties.
Internet Protocol (TCP/IP) Properties window

appears. Select the radio button
‘obtain an
IP address automatically’.


4.1.3

Configure
Windows 2003 as a DHCP Server

Sta
rt

Control Panel

Add/Remove Programs. Click on Add/Remove Windows
Components.

Select
Networking Services
and check it. Then click
Details

button. Select
DHCP

and
Simple TCP/IP Services.

Click
Ok.
Click
Next.

Click
Finish.

Start

A摭楮i獴s慴a癥v呯潬T

䑈CP⸠D
HCP M慮慧敲
appears
.
Click on the
computer
and right
-
click and select
New Scope. New Scope Wizard
appears. Enter the
name

of the


3


scope and its
description
. Enter the starting and ending IP address of the scope as instructed
by the instructor.




Click
Next
. If needed, add
exclusion range

and click
Add
. Click Next. On the
lease
duration
, click
Next
unless specified by the instructor.



4




Select
Yes
for DHCP configure options and Click
Next
. If needed specify the router [default
gateway] address and clic
k
Add
. Click
Next
.



Click
Next

[for DNS server]. Click
Next

[for WINS server]. Select
Yes

for activating the
scope. Click
Next
. Completing the new scope wizard appears. Click
Finish
. DHCP window
appears.





5




4.1.4

Capture DHCP traffic

We will use Etherea
l software to capture DHCP traffic. In order to install this software,
we need to install WinPCap software first. Then, we should install the Ethereal software. After
installation, follow these steps.

1.

Run the Ethereal software. From the
Capture

Menu clic
k
Start
. In the window that
pops up choose the appropriate network interface and Click
Ok
.

2.

Generate DHCP traffic by using the commands
ipconfig /release

and
ipconfig
/renew
at the DHCP client. Stop the DHCP capture.



6









What is the transport layer pr
otocol DHCP uses?



What is the use of port numbers 68 and 67?



Why is that the Source IP address of the DHCP Discover all 0s?



Why is that the Destination IP address of the DHCP Discover all 1s?



What is the relationship between BOOTP protocol and DHCP?



What i
s the use of physical address in DHCP?



Why is the Destination IP address of DHCP Offer all 1s?



7






Is DHCP Request a broadcast? If yes, what is the difference between DHCP Request
and DHCP Discover?



How is the server identifier filled in the Bootstrap prot
ocol?



Does the client assign the IP address it got using DHCP Offer?






Is the DHCP ACK a broadcast? Justify.



8





What does DHCP Release do?



Is DCHP Release Broadcast or Unicast? Justify.

4.2

Network Measurement

4.2.1

Getting ready for measurement

In this experiment
, you are going to collect data about network parameters such as:



Bytes sent/second



Bytes received/second



Bytes Total/second



Current Bandwidth



Packets sent Unicast/second



Packets sent non
-
unicast/second



Packets sent/second



Packets/second

These data will be

recorded for different topologies to be discussed below [Section 5]:

Reference

Name

A

Cascaded shared hubs

B

Segmented LAN

C

High
-
Density Fast Ethernet switched workgroup



9


4.2.2

Creating a Real
-
Time Performance Monitor chart

Create a chart in Performance Mon
itor to display performance data real
-
time.

Note:

For Windows 2003, you can find
Network Monitor

and
Performance Monitor

at:

Start


Programs


Administrative Tools


Network Monitor

Start


Programs


Administrative Tools


Performance


4.2.3

Install the Networ
k Monitor



Click
Start
, click
Control Panel
.



Double
-
click
Add/Remove Programs
.



Click
Add/Remove Windows Components
.



Click
Management and Monitoring Tools
, and then click
Details
.



Select the
Network Monitor Tools

check box, and then click
OK
.



Click
Nex
t
.


Note:

In Windows 2003, Microsoft Network Segment is no longer available with Performance
Monitor. So, we can’t use the
%Network Utilization

option available under Network Segment
in Windows 2003. To view
%Network Utilization,

we have to use
Network Mon
itor

[Select
the network interface and start capture]. As the value keeps on changing, we just view that value
there.


4.2.4

Configure the chart

Click the
Start
button, point to
Administrative Tools
, and then click
Performance
.

To see the
Graph
or
Histogram

or
R
eport
, you can click on
the respective button available
at
the graphical part of the screen
.

Select on
Graph
. To add entries to the chart, right
-
click on the graphical area and select
Add
Counters
.

In the
Performance
Object

box, select
Network Interface
.

Notice that
Processor

is the default object.

In the
Counter

list, to know about an
entry, select that entry and click on
Explain
.



10


Then select the
Bytes Sent/second
,
Bytes Received/second
,
Bytes Total/sec
,
Current Bandwidth
,
Packets/second
,
Packets Sent/sec
ond
,
Packets sent
unicast/second

and
Packets sent non
-
unicast/second
. We can select them at the same
time using Control key.

We have to select all the above entries for both the network cards. We can select both
the network cards in the
Instances

list usin
g Control key.

Click
Close
.

A graph appears, displaying the real
-
time activities for the processor.


4.2.5

Generation of data and its representation on the chart

Starting with topology A [Refer Section 5], for each topology [A to C], we need to
generate some t
raffic. The implementation of this part depends on the available resources for
network traffic generation in the lab. You can just use ping or view something from the server
to generate some traffic.

Example of generating traffic:

Use ping command and gen
erate continuous [repetitive]
traffic to the server [192.168.230.1] with the packet size of 65000.

ping

t

l 65000 192.168.230.1


4.2.6

Summarizing performance data in a Performance Monitor report

Use reports to view data in a non
-
graphical format. To create
a report showing the
network parameters values for the entire graph period


1.

To see the
Report
, you can click on the report button available at the graphical part of the
screen.

2.

A report with the chosen counters is displayed, showing the averages. This repo
rt shows the
values for both the network cards.

Note:

You might get zero value for one network card and some values for another network
card. This will happen if one of the cards is used for data transfer.

3.

Write down the
Average

and
Maximum

values of each
counter in the
Counter

list for the
entire graph period in the tables provided in Section 6.




11


4.2.7

Generating Alerts

In this exercise, you will generate alerts from the collected data. To generate
performance logs and alerts:

1.

On the left pane of the
Performanc
e Window
, click on
Performance Logs and
Alerts
.

2.

Select
Alert
. To add an alert, right
-
click on it.

3.

You can add an alert from a file or add a new one directly.

4.

To add an alert directly, click
New Alert Settings…

5.

Enter the name for the alert in the
Name
text
box.

6.

Click on
Add…

to add counters.

7.

Select the respective Performance Object, Counter and the instance.

8.

In the
Performance
Object

list, select
Network Interface

and

9.

In the
Counter

box, select
Bytes Total/sec

along with one interface card at the
Instances

list
.


10.

Click
Add

11.

Click
Close
if you have selected as many alert entries you need.



12



12.

If you have wrongly selected an entry, you can delete it by selecting the alter entry and
click
Remove
.

13.

Select the alert entry in Counters list, Select
Over

at
Alert whe
n the value is
. Enter
100000 as the
Limit
.

14.

Under
Action

tab, you can set the alert message to be logged on a file or display a
message or run a specific program.



Select the ‘
Log an entry in the application event log
’ option and you can view the
log using:

Administrative Tools



Event Viewer
.



Select the ‘
Send a network message to
’ option and provide the name of the machine
to which you want to see the alert pop
-
up [on your network]. Make the messenger
service is running.

15.

Under
Schedule
tab, you can select t
he time period over which you want to check for
these alerts.






13


16.

Click
OK
.

17.

A similar approach can be followed to add
Counter

or
Trace logs
.


4.2.8

Topology Diagrams

The topologies we set in this lab are the following:








14







4.2.9

Cascade shared hubs

PCs are connected to each other via hubs. Hubs can be connected directly or via patch
panel.

4.2.10

Segmented LAN

Clients are connected to the hub and the server is connected to the switch.
Hubs are
connected to the switch.


4.2.11

High
-
density Fast Ethernet Switched workgroup

PCs are connected to each other via switches. Switches can be connected directly or via
patch panel.

4.2.12

Data
-
entry tables

The description about various network parameters
is

give
n below:

Bytes Received/sec

is the rate at which bytes are received on the interface, including framing
characters.



15


Bytes Sent/sec

is the rate at which bytes are sent on the interface, including framing
characters.

Bytes Total/sec

is the rate at which byte
s are sent and received on the interface, including
framing characters.

Current Bandwidth

is an estimate of the interface's current bandwidth in bits per second
(BPS). For interfaces that do not vary in bandwidth or for those where no accurate estimation
can be made, this value is the nominal bandwidth.

Packets Sent Unicast/sec

is the rate at which packets are requested to be transmitted to
subnet
-
unicast addresses by higher
-
level protocols. The rate includes the packets that were
discarded or not sent.

P
ackets Sent Non
-
Unicast/sec

is the rate at which packets are requested to be transmitted to
non
-
unicast (i.e., subnet broadcast or subnet multicast) addresses by higher
-
level protocols. The
rate includes the packets that were discarded or not sent.

Packets

Sent/sec

is the rate at which packets are sent on the network interface.

Packets/sec

is the rate at which packets are sent and received on the network interface.



Network parameters (Average)

A

B

C

Bytes received/second




Bytes sent/second




Bytes T
otal/second




Current Bandwidth




Packets sent unicast/second




Packets sent non
-
unicast/second




Packets sent/second




Packets/second










16


Topology A

Network parameters

Average

Minimum

Maximum

Bytes received/second





Bytes sent/second





Bytes Total/second





Current Bandwidth





Packets sent unicast/second





Packets sent non
-
unicast/second





Packets sent/second





Packets/second








Topology B

Network parameters

Average

Minimum

Maximum

Bytes received/second




Bytes se
nt/second




Bytes Total/second




Current Bandwidth




Packets sent unicast/second




Packets sent non
-
unicast/second




Packets sent/second




Packets/second







17



Topology C


Network parameters

Average

Minimum

Maximum

Bytes received/second




By
tes sent/second




Bytes Total/second




Current Bandwidth




Packets sent unicast/second




Packets sent non
-
unicast/second




Packets sent/second




Packets/second





Notes:


1.

Both the switches [3Com superstack 3 switch 3300] and hubs [3Com supers
tack II
Hub 100 TX] in our lab supports both 10Mbps and 100Mbps.

2.

The number of bytes received/second and number of bytes sent/second on the clients
will be the same because ping command generates both ICMP echo request [Bytes
sent/second] and ICMP echo re
ply [Bytes received/second] that carries the same data
size. The same applies to the server also because it receives the echo request [Bytes
received/second] from the client and sends echo reply [Bytes sent/second] to the client.

3.

The hubs we have 3Com Supe
rStack II Hub 100 TX (3C250C) handles unicasts
similarly to that of switches. So, you don’t find the entries at the server and the client as
the same.

4.3

Analysis

Y
ou may think that just comparing the Current Bandwidth with the Bytes/Sec proves
that the netwo
rk is at full capacity.

On closer inspection of the Scale, you can realize what is the
difference in scale between the Current Bandwidth and Bytes/Sec.

There is one more factor;
the Current Bandwidth is in bits while the Bytes/Sec is in bytes.

1 bytes = 8
bits.

When you


18


compute all these factors, the actual network utilization can be found. For example, if the
Bytes/Sec average is 103112.


Bytes /Sec = 103,112 bytes x 8

Bytes /Sec = 894,896 bits/Sec.

Current bandwidth = 100Mbps = 100 * 10
6

bps = 100,000,000

bits/Sec

Network Utilization = 894896/100000000 = 0.82%

One of the amazing features of an Ethernet network is that only one machine can
transmit at a time.

Once the network reaches 30% capacity, pure chance means that two
machines try and end a packet at

the same instant.

The result is more and more collisions start
happening, this leads to re
-
transmissions and a slow down of network traffic.


Networks bottlenecks occur at surprisingly low levels of utilization.

40% would
normally be considered a bottlene
ck. The reason for getting a very low utilization value was that
there are fewer machines on network and the traffic generated by each machine is very
minimal.

The more machines the greater the risk of collisions from two machines wanting to
transmit at on
ce.

4.4

References

DHCP FAQ

http://www.dhcp
-
handbook.com/dhcp_faq.html

Performance Monitor

htt
p://www.windowsnetworking.com/articles_tutorials/Windows_2003_Performance_Monito
r.html

Performance Monitor


Getting Started

http://www.computerperformance.co.uk/HealthChe
ck/GettingStarted.htm