[1] go-back-n ARQ

Consider a go-back-n ARQ system with a window size of 3. ================================================= a) Circle (or shade or bold) the sender window after frames 0 through 3 have been sent and ACK 3 has been received 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 b) Circle (or shade or bold) the sender window after frames 4 through 6 have been transmitted, ACK 5 has been received, and the timer for frame 5 has expired. 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 c) After a) and b) have occurred, which frames need to be resent? d) After a) and b) have occurred, which frames have been acknowledged? ================================================= OTA: Please explain how you arrived at your a... click for more

[2] Consider a selective- reject ARQ

Consider a selective-reject ARQ system with a window size of 3. ============================================= a) Circle (or shade or bold) the sender window after frames 0 through 3 have been sent and ACK 2 has been received 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 b) Circle (or shade or bold) the sender windows after frames 4 through 6 have been transmitted, ACK 5 and NAK 5 are received. 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 c) After a) and b) have occurred, which frames need to be resent? d) After a) and b) have occurred, which frames have been acknowledged? =============================== OTA: please explain how you arrived at your answer. Thanks...

Destination address, Data Field,

Given the first 20 bytes (in hexadecimal) of an Ethernet frame: AA AA AA AA AA AA AA AB 01 23 45 67 89 AB CD EF 02 46 8A CE 01 0A 4B 8C ================================================ a) What is the Destination Address (in hexadecimal)? b) What is the length of the data field (in hexadecimal)? c) What is the length of the data field (in decimal)? ================================================ OTA: Please give a full explanation. Thank you.

Stop and Wait Problem

A channel has a bit rate of 64 kbps and a propagation delay of 20 msec. For what range of frame sizes does stop-and-wait give a channel efficiency of at least 50%.

Pure Aloha Question

A group of N stations share a 56-kbps pure ALOHA channel. Each station outputs a 1000-bit frame on an average of once every 100 secs, even if the previous one has not yet been sent (stations are buffered). What is the maximum value of N?