Prerequisite: network layers and latency and bandwidth. Outcome: explain which delays QUIC can remove, and which delays still depend on the application or network.

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Change one condition

Use the five tabs below. The arrow keys move between tabs when a tab has keyboard focus. Nothing connects to a server. The diagrams illustrate protocol rules; they do not run a benchmark.
Open the tour in a separate page for more space. That page also shows all five explanations when JavaScript is disabled.
  1. Select Setup. Change the assumed round-trip time from 20 ms to 200 ms.
  2. Select Packet loss. Drop A2, then recover it. Observe when B2 becomes available.
  3. Select Migration. Switch networks, then validate the new path.
  4. Select Delivery. Compare both policies for position telemetry.

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What the diagrams show

The setup comparison assumes a fresh connection and TLS 1.3. It excludes DNS, loss, Retry, processing time, and TCP Fast Open. Its values show when the client can send a request, not when the response arrives.

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Explain the result

TCP setup takes one round trip before the TLS 1.3 exchange takes another. QUIC combines transport and TLS setup into one round trip under the stated assumptions. These counts do not establish that an application runs twice as fast.
No. One packet can contain data from several streams. The example deliberately loses a packet that contains only A2. QUIC can deliver B2 because stream B has no missing bytes before B2. Congestion control can still reduce the sending rate for the connection.
No. The client needs suitable resumption state, and the server can reject early data. Early data also has replay risks. Applications must restrict which operations can use it.
A missing old value can delay newer values on the same stream. Datagrams can suit replaceable position updates when the receiver detects stale data and handles missing updates. A command that must execute once needs additional application rules, regardless of transport choice.

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Sources and inspiration

The selectable concept cards and side-by-side comparisons take presentation inspiration from PosTQuic by sripad2020. The academy diagrams, text, and interactive code are original. Continue to the stream lab for four- and eight-stream experiments. Explore the 15-card QUIC carousel for more protocol mechanisms.