how to use OOB to discovery and connect?

[long]

Hi, I have read the Bluetooth specification version 4.0 and found this figure

It discribled we could use OOB to disvocery and exchanged device information to connect. But I also found another picture tell about OBB pairing process.It just exchanged TK.

So I'm confused that how to use OOB to discovery a devive and connect it? I can't find any answer from the Bluetooth specification version 4.0. Would anyone give me help?

[Asbjørn]

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.

[Asbjørn]

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?