Information Technology Reference
In-Depth Information
Since each service is identified by a universally unique identifier (UUID),
in this case the search is carried out by providing the UUID. The UUID
are universally recognized, hence they are not related to a particular
server.
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The client is not looking for a particular service, but only wants to know
what are those provided by the server. This discovery mode is named
'service browsing'.
2.5
Bluetooth profiles
Besides, the protocols that allow two units to communicate in a consistent
manner, Bluetooth also defines some
profiles
that are associated with given
applications [6]. The profiles identify which elements of the protocol are needed
in different applications. In this way, devices with limited memory or computing
resources, such as headsets or mouse, may only implement the protocols of
interest for the applications they are intended. New profiles can be added to the
Bluetooth specifications, following the introduction of new applications.
There are some well-known profiles corresponding to Bluetooth 'official
services', and, in particular, the following profiles:
The
Generic Access Profile
(GAP) is the basis on which applications
are built. Its main task is to provide a way to establish and maintain secure
connections between the master and the slave. It sets appropriate specifica-
tions for the security level, for the user interface of all Bluetooth devices and
for all the operational modes.
The
Service Discovery Application Profile
(SDAP) is used by devices to
find out what services are offered by other devices. This profile can work
either as a server (i.e. it can be queried by another device answering with
their own services) and client (querying the other devices). Each unit has all
the information about available services and supported protocols. Bluetooth
devices may use this information to verify whether the interaction with other
devices within the piconet is possible or not.
The
Serial Port Profile
(SPP) is a transport protocol that is used by most
of the other profiles. It emulates a serial link and it is useful especially with
legacy applications that need that kind of link.
The
Generic Object Exchange Profile
(GOEP) defines a client-server
relationship for data exchange. Clients start the transactions, and a slave node
can act as both client and server. As the SPP, this profile is a building block
for other profiles.
The
LAN Access Profile
(LAP) allows a Bluetooth device to connect to
a LAN.
The
Dial-up Networking Profile
(DUNP) allows a PC or laptop to connect
a modem without any wire (e.g. a mobile phone equipped with a modem).
