Why does L2CAP exist in BLE stack?

RE: Why does L2CAP exist in BLE stack?

JoonDong — Thu, 02 Mar 2017 08:35:26 GMT

yes it is..

RE: Why does L2CAP exist in BLE stack?

JoonDong — Tue, 28 Feb 2017 10:16:50 GMT

thank you. It's very helpful.

RE: Why does L2CAP exist in BLE stack?

endnode — Tue, 28 Feb 2017 10:01:55 GMT

And also note that L2CAP does assembly/disassembly on PDU level, ATT_MTU lives on higher layer then L2CAP so it has nothing to do with it.

RE: Why does L2CAP exist in BLE stack?

endnode — Tue, 28 Feb 2017 09:20:37 GMT

Yes. Have you read the BT SIG Core specification or at least some training slides like these? I highly recommend it, might be useful.

RE: Why does L2CAP exist in BLE stack?

JoonDong — Mon, 27 Feb 2017 09:56:59 GMT

So does the answer means that L2CAP provide some(logical channel) of original features in BLE stack e.g. except for assembly and disassembly features?

RE: Why does L2CAP exist in BLE stack?

awneil — Mon, 27 Feb 2017 09:40:34 GMT

You mean, "BLE" = Bluetooth Low Energy ?!

RE: Why does L2CAP exist in BLE stack?

endnode — Mon, 27 Feb 2017 07:56:30 GMT

Hi,

L2CAP role is to provide "logical channels" so you could run multiple protocols on top of BT LE link at the same time. However today you have basically only "ATT" and "Security Manager" messaging defined in the specification (the latter means methods used to establish and manage Secure connection, otherwise all "meaningful" communication should happen on top of "ATT". There are "free" channel IDs (CIDs) which can be dynamically assigned to other protocols but that would mean something proprietary (at least according to BT SIG v4.0/4.1) and I've never seen it. So practically L2CAP is here mainly to be able to manage Security Manager layer (and not mix it with ATTribute and higher layers).

Cheers Jan