Sending MTU Exchange Request as Server

[Thomas Ap]

Hello,

I am currently moving my ESP32 Project from the NimBLE Stack to btstack. I have setup a simple GATT Server that clients can connect to and receive data from. The client devices im working with however don't initiate the MTU Exchange themselves, but rather expect the Server to initiate (see image below for an example). With NimBLE I achieved this by using the ble_gattc_exchange_mtu function upon connection. Is there a similar function or reccomended way to handle this in btstack?

Thank you for your time.

[Matthias Ringwald]

Hi Thomas

In general, the GATT Client is supposed to trigger an MTU exchange, as you've indicated. However, the MTU is valid for both directions and you can trigger an MTU Exchange as a GATT Client - as you did with NimBLE.
With BTstack, you can call gatt_client_send_mtu_negotiation.

Chers
Matthias

> On 26 Nov 2024, at 16:06, Thomas Ap <thomas...@gmail.com> wrote:
>
> Hello,
> I am currently moving my ESP32 Project from the NimBLE Stack to btstack. I have setup a simple GATT Server that clients can connect to and receive data from. The client devices im working with however don't initiate the MTU Exchange themselves, but rather expect the Server to initiate (see image below for an example). With NimBLE I achieved this by using the ble_gattc_exchange_mtu function upon connection. Is there a similar function or reccomended way to handle this in btstack?
>

> Thank you for your time.<expected_connection.png>
>
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