• Sure bigger MTU is better if it is available. Long writes look just like a workaround for small MTU so you can have characteristics over 20 bytes in length even without it. Maybe same memory buffer could be used for both since in reality they may be mutually exclusive? Having both features means that you can have same code logic if at least one (biger MTU or long writes) is supported by client.

    When googling, link in this post https://devzone.nordicsemi.com/f/nordic-­q-a/28388/android-sending-data-20-bytes-­by-ble would suggest long writes are supported on Android and Nordic is using this feature in nRF ToolBox

  • Yeah long writes were the go-to feature in BLE 4.0 and 4.1, since bigger MTU sizes were not available before 4.2.

    You could also combine a bigger MTU with a long write enabling you sizes up to kilobytes which is huge for a LE transport. For my special use-case bigger MTUs however would be more appealing because it would reduce the lag between a http request and its response.


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