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Problem 6, Exam 2004

Hi, I tryed to solve this question but I am not sure if I am in the right path.

To compute the throughput I am using the formula that considers the packet loss ratio ( Throughput = (L/T)(C/sqrt(q)).
Should I assume that B (since it is a router) after achieving the max capacity of link 2 starts dropping packets? Then consider that the packet loss it is 80%. If this is correct this packet loss is the same for both links? And we also should asume that the packet lenght is the same?

Thank you,
Ada
Posted by Ada Lezama Lugo on Friday 10 March 2006 at 15:03
Comments
"Should I assume that B (since it is a router) after achieving the max capacity of link 2 starts dropping packets?"

YES.

"Then consider that the packet loss it is 80%".

I think you don't need a numerical value for the losses.

"If this is correct this packet loss is the same for both links?"

You can assume it is like this.

"And we also should assume that the packet lenght is the same?"
(you mean the parameter "L" in the formula you decided to use): yes.

But you think you are in the wrong path:
-the formula for the throughput that you are using, if L and q are the same for both connections, can give you the ratio between the throughput of the two connections;
-you can derive the sum of the throughput of these two connections (look at the problem)
then you can have the value of the throughput of the two connections without knowing q or L.

To sum up, don't make assumptions when you don't need them!
Hope it can help...
Posted by Gianluca Rizzo on Friday 10 March 2006 at 15:22