07) Transport

What is the role of the transport layer?

End-to-end communication management

What does modularization do?

Breaks network tasks into layers

What layer handles routing?

Network layer

What layer handles end-to-end control?

Transport layer

What is TCP?

Connection-oriented transport protocol

What is IP?

Connectionless network protocol

What is congestion?

Demand exceeds network capacity

What happens during congestion?

Queues fill and packets drop

Who controls congestion?

Transport layer

What is end-to-end principle?

Intelligent hosts dumb network

What do ACKs do?

Confirm successful packet delivery

How are ACKs used?

Infer network conditions

What is sliding window?

Limits unacknowledged packets

What is congestion window cwnd?

Max packets in transit

What happens when ACK received?

Window slides forward

Why use sliding window?

Improve efficiency and control flow

How does TCP increase cwnd?

Additive increase

How does TCP decrease cwnd?

Multiplicative decrease

What is AIMD?

Additive increase multiplicative decrease

What is RTT?

Round trip time

What is timeout?

Wait time before assuming loss

What indicates packet loss?

No ACK within timeout

What is sequence number?

Identifies packet order

What is loss-based congestion control?

Uses packet loss as signal

What does TCP Reno do on success?

Increase cwnd by 1

What does TCP Reno do on loss?

Cut cwnd in half

What is delay-based congestion control?

Uses RTT changes

What are RTT components?

Propagation delay and queuing delay

What does TCP Vegas compare?

Current RTT vs minimum RTT