Timing breakdown phases explained

https://developers.google.com/web/tools/chrome-devtools/network-performance/reference#timing-explanation

Timing breakdown phases explained

Here's more information about each of the phases you may see in the Timing tab:

• Queueing. The browser queues requests when:
  • There are higher priority requests.
  • There are already six TCP connections open for this origin, which is the limit. Applies to HTTP/1.0 and HTTP/1.1 only.
  • The browser is briefly allocating space in the disk cache
• Stalled. The request could be stalled for any of the reasons described in Queueing.
• DNS Lookup. The browser is resolving the request's IP address.
• Proxy negotiation. The browser is negotiating the request with a proxy server.
• Request sent. The request is being sent.
• ServiceWorker Preparation. The browser is starting up the service worker.
• Request to ServiceWorker. The request is being sent to the service worker.
• Waiting (TTFB). The browser is waiting for the first byte of a response. TTFB stands for Time To First Byte. This timing includes 1 round trip of latency and the time the server took to prepare the response.
• Content Download. The browser is receiving the response.
• Receiving Push. The browser is receiving data for this response via HTTP/2 Server Push.
• Reading Push. The browser is reading the local data previously received.