Use BLE without GAP/GATT

[hberg]

I'm currently writing my thesis, and my goal is to establish a network protocol like IP. We need to transmit about 200kB of data between 2 or more nodes once every 10-30 minutes.

My current approach is to use WriteRequests and Notifications/Indications based on GATT characteristics. Basicly a custom NUS service with a application protocol on top of it for fragmentation, reliable transmission and so on.

Is it possible to completly skip GAT / GATT, designing a custom protocol directly on top of the logical link layer L2CAP?

We are using custom hardware with NRF51422 chips on it.

Thanks!

[endnode]

Yes it is, Nordic Soft Devices S13x V2 supports access to L2CAP layer through dedicated API, see more in Soft Device API on infocenter. Note that this is useful only if both parts of the link support it;)

[hberg]

Great! I'm fiddling around with sd_ble_l2cap_tx and getting an BLE_EVT_TX_COMPLETE event, but can't see any packets in the sniffer. Do you know why this is? Thank you for your help!

[hberg]

Seems the sniffer cant' detect the packets. With another board i received the BLE_L2CAP_EVT_RX event! Looks like it is working, great :-)

[hberg]

Do you know where i can find details about L2CAP implemented in the S130 softdevice? E.g. does it support flow control? Is the transmission reliable? What is the maximum packet size? How can i configure all this?

Thanks.

[endnode]

All the official documentation is on that Infocenter page, however if you write L2CAP into the search window on this forum, you will get over 100 threads on this topic. I'm sure you will find many answers there as well;)