TransportLayerII

Question 1

What is TCP’s main service?

Answer 1

Reliable, ordered, and error-checked delivery of a stream of bytes between applications.

Question 2

What is the TCP three-way handshake?

Answer 2

SYN (synchronize) -> SYN-ACK (synchronize-acknowledge) -> ACK (acknowledge) to establish a connection.

Question 3

What are TCP sequence numbers?

Answer 3

Numbers that identify the order of bytes sent and received in a connection.

Question 4

What is an acknowledgment (ACK) number in TCP?

Answer 4

The number of the next expected byte from the other side.

Question 5

What is flow control in TCP?

Answer 5

A mechanism to prevent sender from overwhelming receiver’s buffer space.

Question 6

How does TCP implement flow control?

Answer 6

By using the ‘window size’ field in the TCP header.

Question 7

What is congestion control in TCP?

Answer 7

Mechanisms to prevent network congestion by adjusting the rate of data transmission.

Question 8

What is slow start in TCP?

Answer 8

An algorithm that increases transmission rate exponentially until loss is detected.

Question 9

What happens during TCP fast retransmit?

Answer 9

A packet is retransmitted after receiving 3 duplicate ACKs before a timeout.

Question 10

When does TCP use timers?

Answer 10

To detect segment loss and trigger retransmissions if ACKs are not received in time.