Interview Questions/System Design/Design a Video Conferencing Platform
AdvancedSystem-Design
45 min

Design a Video Conferencing Platform

MediaRealtimeNetworkingSecurity
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Interview Question

Design a scalable video conferencing service like Zoom with low latency, adaptive quality, and security.

Key Points to Cover
  • Media servers (SFU vs MCU) trade-offs
  • Adaptive bitrate streaming and bandwidth estimation
  • Signaling: session negotiation, ICE/STUN/TURN
  • Security: E2EE, key rotation, identity
  • Scalability: regional PoPs, horizontal scaling
Evaluation Rubric
Sound media server architecture25% weight
Low-latency and adaptive streaming25% weight
Strong E2EE and identity management25% weight
Global scalability and multi-region25% weight
Hints
  • 💡Consider trade-offs between SFU and MCU.
Common Pitfalls to Avoid
  • ⚠️Over-reliance on MCU architecture for scalability, leading to server bottlenecks.
  • ⚠️Insufficiently robust bandwidth estimation, resulting in poor quality or frequent disconnections on unstable networks.
  • ⚠️Ignoring the complexities of network traversal and failing to implement STUN/TURN effectively, leading to connectivity issues.
  • ⚠️Treating security as an afterthought rather than an integral part of the design, leading to vulnerabilities.
  • ⚠️Underestimating the signaling overhead and latency implications for large group calls.
Potential Follow-up Questions
  • How to reduce join latency?
  • How to scale breakout rooms?
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