Contrast TCP vs UDP; detect loss
Company: PayPal
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: Medium
Interview Round: Technical Screen
Contrast TCP and UDP in reliability, ordering, congestion control, connection setup, and overhead. How does TCP detect packet loss and trigger retransmission (e.g., timeouts, duplicate ACKs/fast retransmit, and selective acknowledgments)?
Quick Answer: This question evaluates understanding of transport-layer protocols by contrasting TCP and UDP across reliability, ordering, congestion control, connection setup, and overhead, and it probes knowledge of how TCP detects packet loss and triggers retransmission using transport-layer mechanisms.