[SOLVED] algorithm parallel network EE450: Sample Set #6: TCP Congestion Control No Solutions. Will be glad to check your work

EE450: Sample Set #6: TCP Congestion Control No Solutions. Will be glad to check your work
1. The diagram below shows two TCP senders at left and the corresponding receivers at right. Both senders use TCP Tahoe. Assume that the MSS is 1 KB, that the one- way propagation delay for both connections is 100 msec and that the link joining the two routers has a bandwidth of 16Mb/s. Let cwnd1 and cwnd2 be the values of the senders congestion windows. What is the smallest value of cwnd1 + cwnd2 for which the link joining the two routers stays busy all the time?
a. Assume that the link buffer overflows whenever cwnd1+ cwnd2600 KB and that at time 0, cwnd1= 500KB and cwnd2 = 100 KB. Approximately, what are the values of cwnd1 and cwnd2one RTT later? Also, what are the values of ss-thresh for each of the two connections? Assume that all losses are detected by triple duplicate ACKs.
b. After 20more RTTs, approximately what are the values of cwnd1 and cwnd2?
c. Approximately, how many more RTTs before cwnd1+cwnd2600KB again? What is
difference of their congestion windows at this point?
2. Two hosts A and B are communicating through a TCP connection. The maximum segment size (MSS) has been negotiated to be 1kbyte, and the size of the receiver window of B is 50 Kbytes. The network capacity is 1 MBps, the round-trip time is 20ms, and the initial threshold of the Slow Start algorithm is set to 64 Kbytes. An expiration timer of 1s is engaged at the beginning of each transmission burst.

a. If the 4th transmission round is completely lost, how long does it take to reach a congestion window of maximum size after the loss? Clearly illustrate your work (By just giving me a number will earn you NO points)
b. Now assume that the network has a capacity of 10 MBps. Find the Throughput of the session and the maximum efficiency (in the AB direction)
3. Assume that in the network shown there are two parallel TCP transmissions taking place. TCP1 is a transmission between Source A and Sink A that uses TCP Tahoe. TCP2 is a transmission between Source B and Sink B that uses TCP Reno. The Initial ssthresh for both TCP transmissions is set to 32. There are no additional delays other than propagation delays listed above each link.
a. For TCP1 transmission, draw the resulting congestion window assuming that a packet loss is detected via 3 duplicate Acks at t = 900 msec
b. For TCP2 transmission, draw the resulting congestion window assuming that a packet loss is detected via 3 duplicate Acks at t = 650 msec
4. Consider a TCP Reno flow that has exactly 50 segments to send. Assume that during the transmission, exactly five segments are lost: the 4th, 5th, 6th and 48th (due to time out expiration) and segment 22nd (due to 3-duplicate acknowledgements); no other losses occur. Plot the evolution of the congestion window as each segment is sent. Assume the RTO is set to 2RTT and assume that the RTT is 1 sec. Only lost segments are retransmitted. What is the throughput of the TCP session? Assume each segment is 1KByte long.

5.