Assume a TCP connection is established over a 1.2 Gbps link with an RTT of 4 msec.

Assume that when a group of segments is sent, only a Single Acknowledgement is

returned (i.e. cumulative). We desire to send a file of size 2MByte. The Maximum segment

length is 1 Kbyte. Congestion occurs when the number of Bytes transmitted exceeds the

Bandwidth x Delay product (expressed in Bytes). Two types of TCP congestion control

mechanisms are considered. For each type sketch the congestion window vs. RTT

diagram.

a. TCP implements AIMD (with NO slow start) starting at window size of 1 MSS. When

congestion occurs, the window size is set to half its previous value. Will congestion

occur? If Yes, when? If No, why not? Find the throughput of the session and the link

utilization in this case.

b. TCP implements slow start procedure ONLY (i.e. No congestion avoidance phase).

Again it starts with a window size of 1 MSS and doubles every RTT. When congestion

occurs, the window size is reset to 1 MSS again. Will congestion occur? If Yes, when?

If No why not? Find the throughput of the session and the link utilization in this

case.