how to use OOB to discovery and connect?

RE: how to use OOB to discovery and connect?

Asbjørn — Thu, 30 Oct 2014 09:05:11 GMT

Advertising is the essence of how to establish or re-establish a link in BLE. The device that advertises becomes the slave according to Bluetooth spec and the device that initiate the connection becomes the master.

That said, in BLE you are able to do directed advertising which means you're searching for one specific master that you have been connected to previously. This would be the closest you would get. May I ask what your motivation is for not wanting to advertise?

RE: how to use OOB to discovery and connect?

long — Fri, 24 Oct 2014 01:43:54 GMT

Did you see any BT headsets that used NFC to discovery and connection ? Is there any method to connect BT device that doesn't need to advertising. They can build link through some information from NFC.

RE: how to use OOB to discovery and connect?

Asbjørn — Thu, 23 Oct 2014 09:01:06 GMT

The discovery and connection is done as normal with BLE. The OOB procedure is just used to share the Temporary Key (TK) during the bonding sequence. As the TK is used to generate the STK (Short Term Key) and hence the encryption, the TK would be all that you share on the OOB. If this wasn't shared OOB you would have to share the key on the link and that would be the potential weak part of the link establishment. So the connection and bonding of two device would be very much the same, it's just the sharing of the initial TK that's done OOB and hence increases the integrity of the link.