Definition/Use of New UUID Aliases?
Original Post: [bluetooth] SDP - UUID - Conversion (eGroups Msg.
) Date: 2000-08-18
A UUID is a unique
128-bit value to uniquely identify a service class. The predefined UUIDs
are represented as 16/32 bit aliases. All of these 16/32 bit UUID
aliases are actually offsets to the Bluetooth Base UUID
(a predefined 128 bit value, see page 337 - SDP specs). In order to
convert a 16/32 bit UUID alias
to a 128 bit UUID you just do
a simple addition of the alias value to the Bluetooth Base
UUID.
However the question arises
whether it is possible to devise new alias UUID's . For
example the "regular" profiles are usually described by 16/32
bit UUIDs. These aliases are actually just a way of reducing the
amount of bytes being transferred.
New generic profiles MUST not
define 16/32 bit UUID aliases for any 128 bit UUIDs they specify.
Instead you have to define an
ordinary 128 bit UUID to
describe the "UUID-based" attributes.
So lets say you've implemented
a SDP client app.
- When you go to search for a regular, pre-defined UUID
(i.e. using the UUID as a search parameter to location the services of
a profile), you can search using either it's 16/32 bit alias or its
full 128-bit value.
- If you have devised and implemented a new profile,
you can only search for it's 128-bit UUID. any aliases made of your
new 128-bit UUID are illegal.
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