3.7

Question 1

What is TCP congestion control approach?

Answer 1

additive increase, multiplicative decrease

sender increases transmission rate/window size, probing for usable bandwidth until loss occurs

additive increase: Increase cwnd by 1 MSS every RTT until loss is detected
multiplicative decrease: cut cwnd by half every loss

Question 2

How does the slow start algorithm work?

Answer 2

Increase transmission rate increases exponentially until first loss

this is by done by increment cwnd for every ack received

Question 3

What is the TCP fairness goal?

Answer 3

if K TCP sessions share same bottleneck link of bandwidth R, each should have average rate of R/K

Question 4

What are the 2 ways to calculate TCP throughput?

Answer 4

avg TCP thruput = (3/4) * (W/RTT) bytes/sec

TCP Reno throughput = 1.22 . MSS RTT/RTT sqrt( L)
where L is segment loss probability