Computer Networks

What the TCP three-way handshake is, how it works, why three handshakes are needed, and SYN Flood.

What the TCP four-way connection termination is, how it works, why four handshakes are needed, and TIME_WAIT/CLOSE_WAIT states.

What TCP flow control is and how the sliding window controls the sender's sending rate.

What TCP is, why it is needed, its connection-oriented, reliable, byte-stream characteristics, message format, and comparison with UDP.

English translation of the original VNote “TCP KeepAlive”, preserving its original structure and comparison with application-level heartbeats.

What CLOSE_WAIT means, why it is a local application state after receiving FIN, and how persistent CLOSE_WAIT growth points to socket-lifecycle bugs.

What TCP congestion control is, why it is needed, and the slow start, congestion avoidance, fast retransmit, and fast recovery algorithms.

HTTP/1.0 short connections and statelessness, HTTP/1.1 persistent connections and pipelining, and HTTP/2 binary framing and header compression.

What WebSocket is, why it is needed, its role, its relationship with HTTP, and the WebSocket frame format.

English translation of the original VNote “HTTP Status Codes”, preserving the original list of status codes and explanations.