I went straight to broadcast latency and started talking about network topology.
Clarify that the answer depends on the network topology, protocol, and scale, then walk through common scenarios like broadcast in a LAN versus gossip in a large-scale distributed system. Use the opportunity to discuss trade-offs between latency, bandwidth, and reliability, and relate it to real-world systems like blockchain propagation.
Pro tip: Acknowledge that in real-world networks, propagation time is often dominated by protocol overhead and network congestion rather than raw speed of light, and mention that Coinbase deals with similar challenges in blockchain and exchange systems.
Ask about the network size, topology, and protocol (e.g., LAN broadcast, gossip, or blockchain P2P). This shows you consider context before diving into calculations.
Start with a small LAN: propagation time is negligible (microseconds) due to high speed and direct links. For a broadcast, it's essentially the maximum link latency.
For a large network, use a model like gossip: time grows logarithmically with number of nodes if each node forwards to a few peers. Discuss factors like fanout and round-trip time.
Compare approaches: flooding is fast but inefficient; gossip is scalable but has probabilistic delivery; structured overlays (e.g., DHT) offer predictable but higher latency.
Mention examples like Bitcoin block propagation (seconds to minutes) or exchange order propagation, highlighting how Coinbase might optimize for low latency and reliability.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.