Interview Q&A / Computer Networks

INTERVIEW Q&A · 55 QUESTIONS

Computer Networks interview questions

What happens when you open a website, TCP vs UDP, DNS and HTTP.

  1. UDP is unreliable. How can an application still get reliable delivery over it?

    The application adds what it needs on top: sequence numbers to order and detect gaps, acknowledgements and retransmission for missing data, and timers. QUIC, used by HTTP/3, does exactly this over UDP, along with congestion control and encryption.

    AdvancedQuick answer1 min read
  2. What is HTTP/3, and why does it run over QUIC instead of TCP?

    HTTP/3 is HTTP carried over QUIC, a protocol built on UDP that has its own reliable streams, congestion control and built-in TLS 1.3. It avoids TCP head-of-line blocking, connects faster, and survives network changes such as moving from Wi-Fi to mobile data.

    AdvancedQuick answer1 min read