The average round trip time AND an approximation of the mean deviation in round trip time are measured separately for every TCP connection. This is because: Correct operation of the flow control algorithm requires both parameters to be measured The round trip time and variance are both used in calculation of payload CRCs in TCP. Each source-destination pair experiences unique time-varying latency behaviour The time-out period is calculated from both of these parameters Question 10 1 / 1 pts Which of the following is NOT a valid field in the TCP header