# Concepts

There are common concepts used throughout Telemetry:

- {doc}`pings <pings>` - the packets we use to submit data
- {doc}`sessions & subsessions <sessions>` - how we slice a users' time in the browser
- *measurements* - how we collect data
- *opt-in* & *opt-out* - the different sets of data we collect
- {doc}`submission <submission>` - how we send data to the servers
- {doc}`archiving <archiving>` - retaining ping data locally
- {doc}`crashes <crashes>` - the different data crashes generate

```{toctree}
:glob: true
:hidden: true
:maxdepth: 2
:titlesonly: true

pings
crashes
*
```
