CSE 4344 Quiz 2 Terms

What is the primary function of the Transport Layer?

To ensure reliable, in-order data delivery between processes on different hosts.

What are the two main protocols used in the Transport Layer?

TCP (connection-oriented, reliable) and UDP (connectionless, unreliable).

What does RDT stand for in the context of the Transport Layer?

Reliable Data Transfer.

What is the assumption made by rdt1.0?

It assumes a perfectly reliable channel with no errors or loss.

What problem does rdt2.0 introduce with ACK/NAK feedback?

ACK/NAK corruption leads to ambiguity.

How does rdt2.1 improve upon rdt2.0?

It adds sequence numbers to handle duplicate packets.

What is the key difference between rdt2.2 and rdt2.1?

rdt2.2 uses ACKs only (no NAKs) with explicit sequence numbers.

What mechanism does rdt3.0 use to handle packet loss?

It uses timeouts and retransmissions.

What is a performance issue associated with the Stop-and-Wait protocol in rdt3.0?

It is inefficient due to low utilization, resulting in only 267 Kbps throughput on a 1 Gbps link with 30ms RTT.

What is the Go-Back-N (GBN) protocol?

A protocol where the sender maintains a window of N unacknowledged packets and retransmits all unacknowledged packets on timeout.

How does Selective Repeat (SR) differ from Go-Back-N?

SR allows the receiver to buffer out-of-order packets and sends individual ACKs, retransmitting only lost packets.

What are the key features of TCP?

Connection-oriented, reliable in-order byte stream, flow control, and congestion control.

What is the purpose of the TCP 3-way handshake?

To establish a connection between two hosts.

What does the TCP segment structure include?

Sequence number, ACK number, and various flags (SYN, ACK, FIN, RST).

How does TCP handle retransmissions?

It uses timeout-based retransmission and fast retransmit triggered by 3 duplicate ACKs.

What is the function of TCP flow control?

To prevent sender overflow by having the receiver advertise the receive window (rwnd).

What is the Slow Start mechanism in TCP congestion control?

It allows exponential growth of the congestion window (cwnd) until a threshold is reached.

What does AIMD stand for in TCP congestion control?

Additive Increase Multiplicative Decrease.

What is the role of the Network Layer?

To handle forwarding and routing of packets across networks.

What are the components of router architecture?

Input ports, switching fabrics, and output ports.

What is the format of an IPv4 datagram?

It includes a 20-byte header with fields such as TTL, checksum, source/destination IP, and fragmentation fields.

What is classful addressing in IP addressing?

It categorizes IP addresses into classes A, B, C, D, and E based on the number of bits allocated for the network.

What is subnetting?

It divides a network into smaller subnets using a subnet mask.

What are special IP addresses?

Network address, broadcast address, and loopback address.

What does longest prefix matching refer to in forwarding tables?

It is the method used to map destination IP addresses to output ports based on the longest matching prefix.