Assignment #5
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This page contains assignment #5 for Simulation.
This assignment is due on Monday, March 28th in class. Any solutions that
you find "on the web" must be referenced as such.
Situation:
Video can be sent across a network in packets. Video traffic requires very low
delay. We will assume that no more than 1% of packets delivered can have an
end-to-end delay greater than 10 milliseconds (corrected from 100 to 10 on
March 20, 2005). You have a three hop (three router) network with 5-Mbps
links between the routers. You would like to know how much background traffic
can be allowed on the network before video quality is compromised. Figure 1
shows your network, the video source, and video consumer.
Figure 1 - Architecture of server showing job queue, CPU, and one disk
You have made measurements and determined that:
- Background traffic arrvials are Poisson.
- Background traffic packets are uniformly distributed between 100 and 1500
bytes in length.
- Video packets are generated deterministically at a rate of 32 per second.
- All video packets are 1500 bytes in length.
Requirements:
You are to determine the maximum allowable rate of background traffic such
that no more than 1% of video packets experience delay greater than 10
milliseconds. You are also to plot the mean video packet delay and percentage
of video packets with delay more than 10 milliseconds for node utilization
ranging from 15% to 95% in steps of 10%.
Submit a hardcopy and softcopy of your program and a short report (containing
graphs!). In your report, discuss your results. That is, what do your results
mean? The quality (correctness and neatness) of your source code will
factor into your grade. Be proud of your high degree of craftsmanship!
Guidelines and hints:
Some hints are:
- The CSIM M/M/1 simulation (mm1_csim.c) discussed
in class might be helpful to you.
- You will need to use CSIM facilities, tables, and inspector functions for
this assignment.
- The service time for a queue is the packet length divided by the link
data rate (be care with bytes and bits!).
- What should the arrival rate of background traffic packets be for a given
utilization? You can determine this "theoretically".
- A template to help you get started is here...
qos_template..
Extra Credit (10 points):
Determine a reasonable (i.e., implementable) way of minimizing the effect of
reducing the effect of background traffic on video traffic and then evaluate
your idea using your simulation model.
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Last update on March 20, 2005
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