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Assignment 3 - packet loss

Verfasst: 24. Jan 2008 23:22
von mjp

the first milestone wants us ot print out the packet loss and it also wants us to use NetMon to visualize the packet loss. By packet loss, I assume these are packets which were dropped by the drop handler, is that correct? Or is a "packet loss" ment to be packets which do not arrive at the receiver. What I mean is: In milestone two we implement an FEC using XOR. It may happen that (in case of bad luck) two out of three messages (by that I mean e.g. message 1, message2, and a XOR message of message 1 and message 2) are dropped by the drop handler and our handler will not be able to calculate the message and therefore the receiver will not receive a message. Which assumption is correct?

The second question: This depends how the first question is answered: If a message does not arrive at the receiver, because two out of three messages (see above) where droped, how should this be displayed in our program?


Re: Assignment 3 - packet loss

Verfasst: 28. Jan 2008 20:11
von erwin.ait
The receiver should print out the loss rate observed at the receiver. If only a DropHandler is in the stack, then the measured loss rate should pretty much correspond with the loss rate set at DropHandler. If I add your FECHandler to the stack, then I should see that the measured loss rate goes down.

Yes, because DropHandler also simulates "burst errors" you may have to add a lot of redundancy to reach zero loss. (It is not a requirement to reach zero loss)