TransportLayerI

Question 1

What is the main role of the transport layer?

Answer 1

To provide logical communication between processes running on different hosts.

Question 2

What is multiplexing and demultiplexing?

Answer 2

Multiplexing gathers data from multiple applications for transmission. Demultiplexing delivers received segments to the correct application.

Question 3

What does the transport layer use to identify processes?

Answer 3

Port numbers.

Question 4

How is a TCP socket uniquely identified?

Answer 4

By a four-tuple: Source IP, Source Port, Destination IP, Destination Port.

Question 5

What are the two main transport layer protocols?

Answer 5

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

Question 6

Key characteristics of TCP?

Answer 6

Reliable, connection-oriented, provides flow control and congestion control.

Question 7

Key characteristics of UDP?

Answer 7

Unreliable, connectionless, no congestion control, lightweight.

Question 8

What is a socket buffer?

Answer 8

Memory space where data is queued for transmission or reception.

Question 9

What happens when data is handed to TCP for transmission?

Answer 9

TCP segments the data, adds headers (sequence numbers, ports) and passes it to IP.

Question 10

What is a checksum used for in transport protocols?

Answer 10

Detecting bit errors in transmitted segments.