From: Janet Davis (jlnd_at_cs.washington.edu)
Date: Thu Jan 22 2004 - 17:32:30 PST
Oops: The first couple of hints are for question 2, not question 3.
Cheers,
Janet
On Thu, 22 Jan 2004, Janet Davis wrote:
> Here are a few hints on homework 1:
>
> Here's a hint for getting started on problem 3. Page 91 says, "a pair of
> single bit errors, one of which increments a word, one of which decrements
> another word by the same amount, will go undetected." So, not all two-bit
> errors are detected. What does this look like at the bit level? How can
> you characterize the probability of one bit error occuring in the right
> place to cancel another out?
>
> I was asked whether I want to see numeric probabilities for problem 3. I
> do want to see numbers, but they can be pretty approximate. To make your
> computation easier, you can make simplifying assumptions such as
>
> - Any bit in the data is equally likely to be a 1 or a 0.
> - If there are two single-bit errors, they occur in different words.
> - A burst error flips all of the bits in a single word.
>
> Be sure to state what your assumptions are.
>
> For problem 5(a), you may assume that no packets are lost, and that the
> sender always sends a new packet after receiving an acknowledgment.
> Also, you should look at the steady-state throughput, in the middle of the
> connection rather than at the beginning or end.
>
> For problem 5(b), you may assume that the TCP receiver consumes data as
> quickly as it arrives. However, the sender doesn't know that the receive
> buffer isn't filling up; it only knows the advertised window on the last
> acknowledgement it received and the amount of unacknowledged data. You may
> find the description of flow control in section 5.2.4 helpful.
>
> Cheers,
> Janet
>
> --
> Janet Davis
> jlnd_at_cs.washington.edu
> http://www.cs.washington.edu/homes/jlnd/
>
>
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-- Janet Davis jlnd_at_cs.washington.edu http://www.cs.washington.edu/homes/jlnd/ _______________________________________________ Cse461 mailing list Cse461_at_cs.washington.edu http://mailman.cs.washington.edu/mailman/listinfo/cse461
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