Packet Length Extension for L2CAP data transfer

[Youssif]

Hi

From my understanding of the softdevice API, the maximum packet length is set using sd_ble_opt_set(BLE_GAP_OPT_EXT_LEN, &opt), but the actual change to the packet length happens through the function sd_ble_gattc_exchange_mtu_request() and sd_ble_gatts_exchange_mtu_reply(). It is only when these two functions are used that the event BLE_EVT_DATA_LENGTH_CHANGED is thrown with the new packet size.

However, there is no similar API for changing the packet length for L2CAP data transfer. We've tried using sd_ble_opt_set(BLE_GAP_OPT_EXT_LEN, &opt) before sd_ble_l2cap_tx(), but we do not get the BLE_EVT_DATA_LENGTH_CHANGED event nor do we see an increase in the packet length size through the BLE sniffer.

Is increasing the packet length possible for L2CAP data transfer? and if it is, what do we have to do in order to achieve it?

We are using softdevice S132 v3.0.0 on an nrf52.

[Petter Myhre]

Unfortunately, you cannot increase it directly through L2CAP, you have to go through the functions you have listed.

[Youssif]

Thanks. Are there plans to add this functionality so that it can be increased through L2CAP?

[Petter Myhre]

We do not discuss future plans here, if this is something you are interested in you should contact the regional sales manager for your area, if you don't know who it is, send me a PM with your location and I'll let you know.

[jsimmons]

Hi, Could this response be clarified a bit? It is still not clear to me.

The language uses seems to imply that the raw l2cap connection packet length is indeed increased once those functions have been called.

"you have to go through the functions you have listed"

Is this interpretation accurate? Or did you mean that it is explicitly impossible to receive extended packet length through RAW l2cap by any means?

Thank you.