SIG Adopted versus Vendor-specific UUID

[Tim]

Hello,

I would like to be clear on the pros/cons of registering a new SIG-adopted UUID versus a vendor-specific UUID. We are a small developer and the cost of registering a SIG-adopted ID ($2,500USD) is not insignificant. I understand one advantage of SIG-adopted is smaller advertising packets because the IDs are only 16-bit. Is this a significant advantage? Is advertising and/or connect-ability impacted in any way by the 128-bit length of vendor-specific IDs?

Any other considerations in making this decision.

Many thanks,

Tim

[ovrebekk]

Hi Tim

You more or less said it, the only real disadvantage of using a 128-bit vendor specific UUID is that they take up much more room in the advertise packet. 

With the header included a single 128-bit UUID will take up 18 bytes of your advertise packet, leaving only 13 bytes for other fields. Typically you need 3 bytes for the flags, leaving only 10 bytes for a local name etc. 

This is not necessarily a big issue. Often all you need to identify your device is the UUID, and you can also use the scan response packet to add more data to your advertiser. Most phones will scan in the active mode when you have an app running, allowing them to pick up both the advertise packet and the scan response packet from an advertising device. 

Once you connect to a device you will use a 16-bit handle rather than the UUID to address different services and characteristics, and the difference between 128-bit and 16-bit UUID's are less important. 

Best regards
Torbjørn