How to change pdu length?

[antoine98]

Hello, 

I have a doubt with my firmware implementation. 

In my previous implementation i had no security and I was sending packets which were 244 bytes long.

Now i have implemented security through peer manager (bonding Le sc with just works). 

According to the following image:

Now i should consider also the Mic field, which is responsible for encryption. How should i consider it? Should I increase the pdu? How? should i decrease the size of my packets from 244 to 240 in order to consider this additional header? Should i decrease/increase the NRF_SDH_BLE_GATT_MAX_MTU_SIZE? It is not clear for me.

Before the implementation of security communication was correctly performed, now is not.

Thanks in advance to anyone who can help me

[Vidar Berg]

Hello,

The maximum ATT payload will remain the same whether encryption is enabled or not. The Softdevice send functions will return an error code if you attempt to send too much data.

Best regards,

Vidar