Question

The question has parts: a,b,c,d and e.

Intro. To Telecommunications Assign#4 (d) Suppose the same situation as above but sender and receiver use Selective Repeat ARQ What frame(s) would the sender need to retransmit? Explain. 1. Suppose that a sender and a receiver are using ARQ to perform reliable data delivery. (a) In a Go-Back-N ARQ protocol, the window size is 6. Frames with sequence numbers 1, 2, 3, 4 and 5 have been sent. The sender just received an ACK for frame 1. Frames 6, 7,8, 9 and 10 are waiting to be sent Draw the time diagram showing this scenario. (e) Can Selective-Repeat ARQ use cumulative ACKs? Explain. Yes. A cumulative ACK indicates that "all frames up to n have been received And so if a receiver has recelved a contiguous block of frames ending with frame n, it can ACK them cumulatively (b) Which frame(s) can the sender send before it must wait for the next ACK from the receiver? Explain (10) What are the trade-offs between Go-Back-N ARQ and Selective-Repeat ARQ? (c) Some time later, the sender transmitted frames 20, 21, 22, 23, 24, and 26; however, frame 22 got lost. If Go-Back-N is used, what frame(s) would the sender have to retransmit? Explain.