On Fri, Sep 23, 2016 at 10:02:32AM -0700, Christopher Collins wrote: [...] > If your application needs to send larger ATT packets, it needs to > negotiate a greater MTU with its peer. This is accomplished by calling > ble_gattc_exchange_mtu() > (http://mynewt.apache.org/develop/network/ble/ble_hs/ble_gattc/functions/ble_gattc_exchange_mtu/)
There is something else I forgot to add. After MTU negotiation, the connection's ATT MTU is set to the *lower* of the two peers' preferred MTU values. So, if the peer specifies a small preferred MTU, your application may still be unable to send full-sized notifications. In the worst case, the peer could specify a preferred MTU of 23 bytes. If this happens, MTU negotiation will have no effect on the maximum size ATT packets your application can send. Thanks, Chris
