One dropped packet stalls all HTTP/2 streams. HTTP/3 streams remain independent.

What you're seeing

HTTP/2 multiplexes streams over one TCP connection. TCP guarantees in-order delivery → one lost packet blocks all streams' bytes after it.

HTTP/3 streams over QUIC are independently sequenced. A loss on stream A doesn't block streams B, C, D. Huge win on lossy networks (mobile, wifi).

★ KEY TAKEAWAY
HTTP/2 over TCP: one lost packet blocks ALL streams. HTTP/3 over QUIC: only the affected stream blocks.
▶ WHAT TO TRY
  • Click Run scenario.
  • Compare the two timelines — HTTP/2 has black bars across all streams after the loss; HTTP/3 only on stream 0.
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