In our discussion of tcp congestion control we implicitly assumed that the tcp sender always had data to send. consider now the case that the tcp sender sends a large amount of data and then goes idle (since it has no more data to send) at t1 . tcp remains idle for a relatively long period of time and then wants to send more data at t2. what are the advantages and disadvantages of having tcp use the cwnd and ssthresh values from t1 when starting to send data at t2 ? what alternative would you recommend? why?

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.