Intermediate LevelREST APIs & Web Services
How does HTTP/2 Flow Control handle Backpressure between client and server?
❓ Interview Prompt: Explain HTTP/2 stream flow control, `WINDOW_UPDATE` frames, backpressure handling, and preventing fast producers from overflowing slow consumer buffers.
When streaming high-volume data over HTTP/2, a fast server (producer) can easily overwhelm a slow client (consumer) network buffer (Backpressure):
HTTP/2 Flow Control Solution:
HTTP/2 implements credit-based flow control at both connection and stream levels:
1
The receiving client specifies a receive window size.
2
As the client reads data from its buffer, it sends 'WINDOW_UPDATE' frames back to the server, granting additional bytes.
3
If the client buffer fills up, it stops sending 'WINDOW_UPDATE' frames. The server detects 0 available window size and pauses streaming until the client catches up!
Code Implementation Example
http
// HTTP/2 Frame Sequence:
[DATA Frame: Stream 1, 16384 bytes] -> Client Buffer fills up
[WINDOW_UPDATE Frame: Stream 1, 65535 bytes] -> Client signals buffer capacity ready💡HTTP/2 WINDOW_UPDATE frames managing receiver buffer flow control.
🎯 Interview Key Takeaway
HTTP/2 credit-based flow control uses WINDOW_UPDATE frames to handle backpressure and prevent buffer overflow.
#HTTP/2#Flow Control#Backpressure#Intermediate
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