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Fundamentals of Communication Networks Prof. A. Pattavina IV exam – 15 July 2020 Surname and name: (upper case) Signature: (your readable signature) Matricola ID: Pag. 1/6 1 - Exercise* (9 points) Consider a file transfer from host A to host B over a TCP connection. Given the following assumptions: • Segment and ACK transmission time is negligible • All segments allowed by the send er window are instantaneously sent by the transmitter; all the ACKs sent by the receiver are sent instantaneously; segment and ACK processing time is negligible • The round trip time RTT is constant • The two hosts are connected by a radio link over a distance d = 300 km • File size B = 18 kbyte. • MSS = 200 byte • Time-out To = 2 RTT • At the beginning of the TCP session (at time t = 0): • Rwnd = 3200 byte • Ssthresh = 3600 byte • Cwnd = 400 byte • In the interval [11,13] ms, there is a temporary outage of the connection and all the segments/ACKs in flight get lost; the connection becomes available again immediately after • At time t1 = 24 ms, the receiver transmits to the sender its new window value Rwnd = 1200 byte 1) Draw in a diagram the values of Cwnd, Ssthresh and Rwnd as a function of time, normalizing time to RTT and window-size to MSS with first transmission of segments starting at t = 0 2) Compute the total transfer time Ttot of the file from start of segment transmission until the last ACK is received * Fundamentals of Communication Networks Prof. A. Pattavina IV exam – 15 July 2020 Pag. 2/6 2 - Exercise (7 points) A private company owns the following IP CIDR address block: 16.16.16.0/20 to be used in the network shown in the picture below. The company has five departments with the following requirements in terms of connected hosts: • Dept. A: 10 hosts • Dept. B: 62 hosts • Dept.…