Computer Networks - Ch. 3 Transport Layer

What information does a host use to direct segment to the appropriate socket in a connection oriented demultiplexing service?

Host uses the 4-tuple: (source IP, source port, dest IP, dest port).

Examples of well-known port numbers.

HTTP: 80, HTTPS: 443, SMTP: 25, DNS: 53, FTP: 21.

What are the sender actions in UDP protocol?

Create segment, add UDP header, hand to IP.

What are the receiver actions in UDP protocol?

Check header, verify checksum, deliver data to socket.

What does it mean UDP is connectionless?

No handshake; each segment is independent.

Where is UDP used?

Streaming, DNS, VoIP, gaming — low latency preferred.

UDP checksum field; exercises.

Detects errors in header and data (optional in IPv4, required in IPv6).

What are acknowledgment and negative acknowledgment packets?

ACK: confirms data received correctly. NAK: indicates error/loss; retransmit needed.

Explain the stop-and-wait approach in a transport-layer protocol.

Sender transmits one packet, waits for ACK before sending next.

Explain the pipelined protocol in operation.

Sender transmits multiple packets without waiting for ACKs, improving efficiency.