TCP GCIA Practice Questions (Page 9)

Questions 41–45

1. 41expert · hard

   A network administrator is tuning a TCP connection that is transferring a large file. The connection is in congestion avoidance, and the congestion window is 64 KB. The round-trip time is 50 ms. The administrator wants to maximize throughput without causing congestion. What is the maximum throughput the connection can achieve, assuming no packet loss?

   • A1.28 Mbps
   • B5.12 Mbps
   • C20.48 Mbps
   • D10.24 Mbps
   Reveal Solution Discussion Select an answer first
2. 42application · medium

   A software developer is designing a real-time voice application that can tolerate occasional packet loss but requires low latency. Which transport protocol should the application use, and why?

   • AUDP, because it provides low overhead and no retransmission delays.
   • BTCP, because it guarantees ordered delivery and reliability.
   • CUDP, because it guarantees delivery of all packets.
   • DTCP, because it provides flow control to prevent receiver overload.
   Reveal Solution Discussion Select an answer first
4. 43application · medium

   A TCP sender transmits segments with sequence numbers 1000, 1400, and 1800. The receiver sends an ACK with acknowledgment number 1400. What does this ACK indicate?

   • AThe receiver has received all three segments and is acknowledging the last one.
   • BThe receiver has successfully received all bytes up to sequence number 1399 and expects the next byte at 1400.
   • CThe receiver is advertising a window size of 1400 bytes.
   • DThe receiver has received the segment starting at 1400 and is acknowledging it.
   Reveal Solution Discussion Select an answer first
5. 44expert · hard

   A TCP connection is in the ESTABLISHED state. The application on the server calls close(), and the server sends a FIN. The client receives the FIN and sends an ACK. The client application then also calls close(), sending its own FIN. The server receives the client's FIN and sends an ACK. Which side enters TIME_WAIT, and why?

   • AThe client, because it received the first FIN and must wait for any delayed segments.
   • BThe server, because it sent the first FIN and must ensure its final ACK is received.
   • CBoth sides enter TIME_WAIT.
   • DNeither side enters TIME_WAIT because the connection closed gracefully.
   Reveal Solution Discussion Select an answer first
6. 45expert · hard

   A security analyst is examining a TCP handshake and notices that the client's ISN is 0. The server's ISN is 1000. The analyst suspects that the client is using a predictable ISN generation algorithm. Why is a predictable ISN a security concern?

   • AIt prevents the use of window scaling and other TCP options.
   • BIt allows an attacker to predict the next sequence number and hijack the connection.
   • CIt causes the connection to be less reliable due to sequence number collisions.
   • DIt makes the connection vulnerable to denial-of-service attacks by exhausting the sequence space.
   Reveal Solution Discussion Select an answer first