Show Bid Request
Datalink layer protocols in java
Bid Request Id: 62742
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Posted by: |
jonnyr1982 (2 ratings)
(Software buyer rating 8.5 )
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Non-action Ratio: |
Very Good - 0.00%
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Buyer Security Verifications: |
Good
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Approved on: |
May 12, 2003
9:29:00 AM EDT
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Bidding Closes: |
May 15, 2003
11:00:00 AM EDT
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Viewed (by coders): |
96 times
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Deadline: |
5/16/2003 11:00:00 AM
TIME EXPIRED
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Description:
the actual questions reagrding the completion of this work are in the deliverables section. However I have included a brief introduction into the general idea of this work.
*NOTE* I have already completed the first part of this work (the designing of the code). All I require is for you to create an evaluation and testing to the code that I will supply.
Introduction:
You have been supplied with Java code which simulates an unreliable physical medium and
provides a framework for the design and implementation of your own datalink layer protocols.
Three protocols are given as part of the framework:
• ProtocolNone: passes frames between applications and the physical layer without
examining or modifying the frames in any way.
• ProtocolErrorCheck: appends a CRC checksum to application frames destined for the
physical layer and drops frames which are subsequently damaged by that physical layer.
• ProtocolPAR: implements a fully-functioning bi-directional 1-bit sliding window
protocol which drops frames which have been damaged in transit but is capable of resending
frames which have been dropped due to such damage or dropped by the
physical layer itself.
In this project, you will design and implement two protocols; Go-back N and Selective
Repeat (*NOTE THIS PART HAS ALREADY BEEN COMPLETED AND IS NOT NEEDED*). You will then assess the performance of your protocols in comparison with
ProtocolPAR, presenting the results in a final report.
Students must not modify the code framework in any way with the exception of class Project,
class ProtocolGoBackN and class ProtocolSelectiveRepeat.
Students should be aware that this is not a Java project. While code should be well structured,
marks are not given for code performance. Your code will be submitted as evidence of your
work.
Deliverables:
1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done.
2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request.
3) Complete ownership and distribution copyrights to all work purchased.
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Below is the exact work that I wish you to complete. This actual code for this work is attached below. All that is required is to create evaluation and testing procedures to the code attached.
Evaluation
You will be supplied with a modified code framework in which the Client can send a fixed
number of messages before “terminating” a processing cycle. You will be able to select this
number at the time the client object is created.
Modify the Project Class to repeatedly execute and time processing cycles, varying the
protocol (PAR, Go back N, Selective Repeat), physical layer parameters (error rate, drop rate,
bandwidth) and protocol parameters (timeout period) as required to investigate the following:
• How do the protocols perform as the error rate varies between 0% and 50%
o Keep other parameters constant (drop rate = 0%, bandwidth = 57600 bits per
second, delay = 0ms)
• How do the protocols perform as the drop rate varies between 0% and 50%)
o Keep other parameters constant (error rate = 0%, bandwidth = 57600 bits per
second, delay = 0ms)
• How do the protocols perform as the bandwidth varies between 9600 and 115200 bits
per second (typical serial link speeds)
o Keep other parameters constant (error rate = 10%, drop rate = 10%, delay = 0ms)
• How do the protocols perform as the delay rate varies between 0 and 1000ms (typical
satellite channels)
o Keep other parameters constant (error rate = 10%, drop rate = 10% , bandwidth
= 57600 bits per second)
• How do the protocols perform as the protocol timeout period varies between 0 and
1000ms
o Keep other parameters constant (error rate = 10%, drop rate = 10% , bandwidth
= 57600 bits per second, delay=200ms)
Deliverable 3: A series of five graphs presenting the results of your evaluation.
Analysis
Analyse the results obtained from your evaluation and explain the relative performance of the
three protocols (PAR, Go Back N and Selective Repeat) with reference to your graphs (what is
it about the protocol which makes it behave in the way it does).
Answer the following questions, quoting evaluation evidence for your answer in each case:
• Which protocol would you use on a physical channel with a low error rate?
• Which protocol would you use on a physical channel with a high error rate?
• Which protocol would you use on a physical channel with a low drop rate?
• Which protocol would you use on a physical channel with a high drop rate?
• Which protocol would you use on a physical channel with a low bandwidth?
• Which protocol would you use on a physical channel with a high bandwidth?
• Which protocol would you use on a physical channel with a low delay?
• Which protocol would you use on a physical channel with a high delay?
• How is protocol performance affected by its timeout period?
Deliverable 4: A report presenting the results of your analysis and all supporting evaluation
evidence.
Deliverable 5: Your Java code: Classes Project, ProtocolGoBackN, ProtocolSelectiveRepeat
and any new classes introduced.
Platform:
Program must run in java. DEADLINE IS THURSDAY 05/15/2003 18:00 CET
Must be 100% finished and received by buyer on:
May 16, 2003 11:00:00 AM EDT
Deadline legal notes: All times are expressed in the time zone of the site EDT (UT - 5). If the buyer omitted a time, then the deadline is 11:59:59 PM EDT on the indicated date.
Additional Files:
This bid request includes IMPORTANT additional attached files. Please download and read fully before bidding.
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Bidding/Comments:
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Bid Amount
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Date |
Coder Rating |
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$35 (USD)
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May 13, 2003
9:44:41 AM EDT
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10
(Excellent)
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dear buyer,
i have modified the Project.java and ran some simulation on protocol 0 and 4. protocol 4 i have checked across all 5 simulation types. you may check the sample output given below.
to clarify your reqmt, i understand that you want 'performance' or throughput analysis compared across the protocols... so i assume analysis regarding no of dropped packets, error rates, latency/delay etc is *not* required. performance data is already captured in code using timer.time(), so i don't think new code is to be written to time it.
i saw some problem running protocol 0 (probably just delay, i cut it short), barring such problems, i can provide the analysis, graphs (done in excel), and analyis report in word document. pls let me know if you want anything else.
thanks
vivek
output begin:
----------------
...
...
40 584
50 1021
Finishing simulation for error rate variation
Starting simulation for drop rate variation
0 58
1 58
2 58
3 148
4 93
5 58
6 177
7 157
8 137
9 207
10 221
15 173
20 371
30 454
40 900
50 653
Finishing simulation for drop rate variation
Starting simulation for Bandwidth rate variation
3 287
...
...
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VivekD