Difference between Doze Mode and Sleep Mode in Android Marshmallow

Sleep Mode - means CPU will be sleeping and will not accept any command except from RIL(Radio Interface Layer) and alarms. CPU will go to sleep mode with in fraction of seconds after LCD is turned off.

Doze Mode - means that apps on your phone will have no network access, the system will ignore “wakelocks” when apps try to keep the device from going to sleep, and no background tasks will be allowed to run. That certainly makes it sound like your phone won’t do you much good, but there are a few ways Doze preserves functionality. While apps can’t wake the device up to run sync jobs and other background tasks, high-priority push messages will still show up. So for example, a Hangouts message will appear on a device that’s in Doze mode.

App Standby - an app that goes into standby loses all network access and all its background sync jobs are suspended. These restrictions are temporarily lifted when your phone is plugged in and for a few minutes every day or two. This gives suspended apps a chance to run any pending sync jobs, but they won’t be allowed to continue running. A high-priority push notification will also be able to wake an app from standby for a short time.

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