Congestion Control

Which statements describe why TCP introduces high latency? (2 correct answers). TCP requires a 3-way handshake before data transfer. TCP encrypts all traffic by default. TCP needs multiple RTTs before sending application data. TCP is unreliable by design. TCP blocks all packets when congestion appears.

Why is QUIC implemented on top of UDP? (3 correct answers). UDP is easier to modify than TCP. UDP provides built-in encryption. UDP avoids strict in-order delivery. UDP allows fast deployment of new protocols. UDP guarantees congestion control.

What layers does QUIC replace? (3 correct answers). TCP. TLS. HTTP/2. IP. DNS.

Which problems of HTTP/2 over TCP does QUIC solve? (2 correct answers). Head-of-line blocking. Lack of encryption. Single connection multiplexing. Packet reordering. Slow congestion control.

What happens when a packet is lost in TCP-based HTTP/2? (1 correct answer). Only the affected stream pauses. All streams are blocked. The connection is closed. The server restarts. The packet is ignored.

What is Forward Error Correction (FEC) in QUIC? (2 correct answers). A retransmission-based mechanism. A redundancy mechanism. A network-level RAID. A congestion control algorithm. A compression technique.

What is the overhead introduced by FEC? (1 correct answer). 1%. 5%. 10%. 25%. 50%.

Why is reducing the number of packets important? (2 correct answers). Wireless RTTs are high. Routers cannot handle many packets. TCP+TLS requires many round trips. QUIC forbids retransmissions. UDP is slower than TCP.

What is the purpose of the QUIC Connection UUID? (2 correct answers). Maintain connection across IP changes. Replace DNS resolution. Avoid reconnecting after handover. Improve encryption. Reduce packet size.