Chrome Developer Tools - Network "Content Download" column

I've got a question about the Chrome Developer Tools - Network Tab - "Content Download" part in the waterfall column. What exactly does this mean? Is latency somehow relevant to this?

Retrieving speedtest.net configuration...
Testing from ...
Retrieving speedtest.net server list...
Retrieving information for the selected server...
Hosted by SWU TeleNet GmbH (Ulm) [517.69 km]: 19.686 ms
Testing download speed................................................................................
Download: 1384.14 Mbit/s
Testing upload speed................................................................................................
Upload: 217.22 Mbit/s

Retrieving speedtest.net configuration...
Testing from ...
Retrieving speedtest.net server list...
Retrieving information for the selected server...
Hosted by DNS:NET Internet Service GmbH (Berlin) [2.30 km]: 17.918 ms
Testing download speed................................................................................
Download: 2455.88 Mbit/s
Testing upload speed................................................................................................
Upload: 684.83 Mbit/s

1 Answer

When you request something from a web server, you (generally¹) send an HTTP request. How long it takes to send the request is measured in the "Request sent" field.

"Waiting (TTFB)" is the time between the end of the request and the start of the response form the web server. (TTFB stands for Time To First Byte.)

"Content Download" measures how long it took to download the response to the HTTP request after the latency is over.

There is more information available in the documentation.

I've seen two definitions for latency:

1. The time between the request and the response. (This would be "Waiting (TTFB)")
2. The amount of time it takes a packet to travel from the source to the destination. (This would affect "Content Download".)

¹ I say "generally" because there are also other protocols in use on the web that aren't HTTP, but HTTP requests are what you're going to see most often in loading websites and activity from JavaScript requests.