$4.$ TCP estimates its timeout value based on measurements of packets$$ round trip time $($RTT$).$ As RTT increases, the timeout value increases as well. The variability in RTT is also factored into the calculation. If RTT is a consistent value, the timeout will be closer to the measured RTT$.$ If there is a lot of variability in RTT$,$ then then timeout will increase. TCP only tracks the RTT of a single packet at a time. When one ongoing RTT measurement finishes, a new measurement will be started when the next packet is sent. This means that RTT is not measured for every packet sent. These measurements are then combined together using a moving average, so as not to give too much weight to any one reading $($which may not be representative of the curr

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