19. TCP in action: Consider the figure below, beginning of each time unit (where

Question

19. TCP in action: Consider the figure below, beginning of each time unit (where the unit of time is equal to which plots the evolution of TCP's congestion window at the the abstract slow start, congestion avoidance, and fast retransmit. the the RTT); In at the beginning of model for this problem, TCP sends e end of the e rel of sending that flight of packets is that either (@) all packets are a triple duplime unit, (ii) there is a timeout for the first packet, or (iii) there of a "flight" of packets of size cwnd time unit. The of ACKed at th is a triple dupli at th for the first packet. In this problem, you are asked to reconstruct shown below of events (ACKs, losses) th s, losses) that resulted in the evolution of TCP's cwnd 45 40 35 30 25 20 15 10 Time unit (in RTT) onsider the evolution of TCP's congestion window in the example above and answer the ollowing questions. The initial value of cwnd is 1 and the initial value of ssthresh hown as a red +) is 8 Give or Mark the times at which TCP is in slow start, congestion avoidance and fast recovery at the start of a time slot, when the flight of packets is sent. . Give or Mark the times at which the first packet in the sent flight of packets is lupeaaketlo ple lost, and indicate w duplicate ACKs.

Explanation / Answer

a. 1-3, 18-21, 34-37 These are the times when the TCP is in slow start.

b. 3, 18, 23, 33, 38 are times when the packet is lost. The packet loss at 23 is an example of triple duplicate ack where as the rest are complete packet loss.

c. At the time of packets losses as mentioned in b. the value of ssthresh changes.

Timeout time New ssthresh 3 2 18 8 23 5 33 9 38 4

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.