This document summarizes an OPNET lab on network design. The lab involved designing a network for a small company with 4 departments. Different scenarios were modeled and compared, including using separate servers versus one server for all services. High density cables were found to optimize network performance. Using separate servers distributed the load better than one server handling all services. Overall, the lab demonstrated fundamentals of network design and how choices like infrastructure and server configuration impact performance.
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Opnet lab 4 solutions
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Opnet Lab 4 Solutions
NETWORK DESIGN
Planning a Network with Different Users, Hosts, and Services
Haider Nafaa Nseif
ID:I201521051
9/1/2018
IRAQ
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OVERWIEW:
In this lab we developed a company's network having 4 departments. Since it was a
small network, we used LAN model. We used OPNET Guru to simulate the network
design. Once the design was done we assessed the outcome and tried to excel the
network by changing some of the hardware, such as using separate servers for
database, files and web vs. using one for all three of them. We also compared the same
network using low vs. high density cables. Thus, this lab is about the optimization of
network.
OBJECTIVE:
The main goal of this lab was to show the learning of the fundamentals of network
design. In order to doing this we took into account the users, services, and locations of
the hosts.
IMPLEMENTATION PROCEDURE:
To implement this network, we used OPNET Guru as it is one of the greatest tools in
Networking. It allows one to simulate the network with any combinations of devices and
protocols we have available today. First, we created an empty project and added objects:
Application Configuration, Profile Configuration, and a subnet as node_0, node_1 and
subnet_0 respectively. Then, we configure services for applications, namely: engineers,
researchers, salespeople, and multimedia users. Later, we configure the subnet. Then,
we create a 10-workstation star topology LAN. We do this for each of the four
departments stated above. Now, we configure all the departments. Now, we configure all
three servers based on different services needed for each followed by connecting each
department to the subnet.
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Finally, we setup the network to test for statistics about the global page and run the
simulation to assess the results. Later, we keep the same setup as in Figure 1 above and
change the background utilization to be 99 percent to create the Busy Network. And run
the simulation again. Finally, we duplicate the Busy Network and replace the low density
cables with high density to observe differences. Now you are you are ready to observe
the results and analyze the network.
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OBSERVATION AND RESULTS ANLAYSIS:
In figure 4.3 bellow, we observed that the response time of the busy network was much
higher than the simple network. Also, the system stabilizes very quick compared to the
busy network.
From figure 3, high density cables were very helpful in optimizing the results. With high
density cables we get busy network producing a response time as if it were a simple
network and it stabilizes really fast too.
It was apparent that File server stabilizes a lot faster than both the Database Server and
the Web Server. Second, Database Server fluctuate the least. It became apparent that
one server replacing the three server has the most load, so it CPU Utilization is the most
and it somewhat higher than the Web Server alone.
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QUESTION AND ANSWERS:
Question 1: Analyze the result we obtained regarding the HTTP page response time.
Collect four other statistics, of your choice, and rerun the simulation of the Simple and the
busy network scenarios. Get the graphs that compare the collected statistics. Comment
on these results.
Answer: From the HTTP response time for the simple and busy networks, the simple
network is represented in blue and the busy network is represented in the color red. The
comparison of the two time delay would result in a conclusion that the delay is much less
in the simple network as compared to the busy network.
We have considered four other scenarios for comparison and they are depicted in the
graph as below:
The first plot shows the Ethernet delay time and from the figure we could notice clearly
that the delay in the busy network is higher as compared to the simple network.
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The next plot shows the time delay comparisons of the TCP delay. We could understand
that the TCP delay for the busy network is fluctuating initially at a higher rate and then it
subsides almost even but still at a higher pace. On the other hand the simple network
has a very low fluctuating initial time delay and then it has stabilized after a period of
time.
The graph below represents the response time for the DB entry and the comparison
between the simple and busy network shows a great deal of difference. The busy
network is a bit fluctuating at the initial stage and then it commences to a stable state.
But still the delay is high over here. The simple network is having a quite stable time
responde from the beginning. This could be observed from the graph below.
The response time for the DB Query is as shown below. In this scenario also the simple
network has a quite stable time delay and very small when compared to the initial
fluctuating time delay of the busy network.
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Question 2: In the Busy Network scenario, study the utilization% of the CPUs in the
servers (Right-click on each server and select Choose Individual Statistics ? CPU ?
Utilization).
Answer: The CPU utilization during the Busy Network Scenario for the webserver,
database server, and file server are as below:
From the graphs above, it is obvious that File server stabilizes a lot faster than both the
Database Server and the Web Server. Second, Database Server fluctuate the least if you
look at the magnitude on the y-axis.
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Question 3: Create a new scenario as a duplicate of the Busy Network scenario. Name
the new scenario Q3_OneServer. Replace the three servers with only one server that
supports all required services. Study the utilization% of that server¡¯s CPU. Compare this
utilization with the three CPU utilizations you obtained in the previous question.
Answer: It is apparent from the graph that the one server replacing the three servers has
the maximum load, so its CPU Utilization is the most and it somewhat higher than the
Web Server in the previous scenario. This is because the web server was using the most
CPU time in the previous busy scenario.
Question 4: Create a new scenario as a duplicate of the Busy Network scenario. Name
the new scenario Q4_FasterNetwork. In the Q4_FasterNetwork scenario, replace all
100BaseT links in the network with 10Gbps Ethernet links and replace all 10BaseT links
with 100BaseT links. Study how increasing the bandwidth of the links affects the
performance of the network in the new scenario (e.g., compare the HTTP page response
time in the new scenario with that of the Busy Network).
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Answer: After making all the changes to the links, we have the following results:
From the results above, it is obvious that network response time is much faster and that it
stabilizes really fast too. In other words, the Q4_FastNetwork is compatible to Simple
Network instead of Busy Network only because we used high density cables.
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CONCLUSION:
In conclusion, we learned the basics of designing a network, taking into consideration the
users, services, and locations of the hosts. We learned this by using OPNET tool which is
great for simulating network systems. We also, learned that using high density cables will
optimize the network greatly and can even convert the response time of a network to be
so fast as if it were a simple network and it stabilizes the network very fast too. We also
noticed that using separate servers for different activities, such as, Database, files and
web gives better performance of CPU utilization. Thus, one should consider using high
density cables and separate servers for Databases, files and Web to avoid overloading
just one server.