Full solutions for full problem please! PLEASE DO NOT ANSWER IF YOU ARE NOT GOIN

Question

Full solutions for full problem please! PLEASE DO NOT ANSWER IF YOU ARE NOT GOING TO ANSWER FULL PROBLEM (I've used a question already on this and got a completely irrelevant answer that did not apply)

5. (20 points) Why TCP can be better than stop-and-wait ARQ: Consider what is called the selective repeat ARQ scheme". Assume that each packet lasts P sec and that the sender and receiver have a buffer of W packets that is large enough so that WxP S, where S is the time needed for a packet to be correctly acknowledged by the receiver to the sender [see class notes on ARQ analysis!], as shown in the figure below for a buffer of size W -4. WP PACKET PACKET PACKET PACKET Also assume that w is so large that is in effect infinite, and that the retransmission timeout T is such that T S, and that the probability that a packet and its ACK are delivered correctly is 1 -p. Show that the efficiency of this ARQ scheme equals 1 -p Hint: Use the approach we used for stop-and-wait ARQ but be careful on considering time elapsed or attempts!

Explanation / Answer

For ideal SRP, only packets containing errors will be retransmitted .

Ideal is not realistic because sometimes packets may have to be retransmitted because their window expired. However, if the window size is set to be much larger than the timeout value then this is unlikely .

With ideal SRP, efficiency = 1 - P

P = probability of a packet error

here what we say that efficiency means no error.So effieciency =1-error probability.

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