After a socket is created, it needs to be assigned a role. BtLibSocketCreate() also takes a callback function pointer as an argument this callback is associated with the socket and will receive all of the events for that socket. The application creates a socket by calling BtLibSocketCreate(), which allocates a socket structure and associates it with a protocol. The SDP interface uses the sockets-based API as well, but that will be discussed further in the following section.

The L2CAP and RFCOMM protocol layers are exposed in the Bluetooth API through a sockets-based interface. Given that a 10-meter distance is not far, one could yell loud enough to overcome the security barrier-unfortunately, your communication would be heard by all! The intercom profile is simpler and does not require security (it is really just an option). In such a controlled environment, bandwidth considerations (the number of users that can be supported by the gateway) can be managed effectively. For larger numbers of users, the address of the gateway could be provided to a fixed number of users. Placing the device in the non-discoverable mode also limits access to the gateway to those already cognizant of its presence (these are typically regulars that work within the same office space). Also, being deployed in a friendlier environment, the level of security used can be relaxed to Mode 2. Bandwidth considerations are not that important when compared to the convenience for potential users. Under this situation, terminal units are able to collect information about the gateway via SDP and choose to continue in establishing a connection. Also, with a fixed number of users known, gateway access may not be a concern. Mode 2 security is best used in a controlled environment such as an office where users are known.

Others that are aware of the gateways presence could connect without having to go through the discovery process. Another approach would be to enhance this security by making the gateway non-discoverable further preventing the occupation of a radio link by casual Bluetooth users. Only users that could enter the correct PIN would be able to establish a link with the gateway. In doing so, you would prevent the loss of an otherwise useful and limited resource: the radio link. Mode 3 may be appropriate, quickly keeping radio connections from being established for unauthorized users. In a public environment, a gateway may be provided for users to access the PSTN. Authentication and encryption are to be used and the bonding process is to be initiated by the terminal unit. It is mandatory to use security modes 2 or 3 you get to select. In Bluetooth Application Developer's Guide, 2002 Cordless Telephony and IntercomĪbove the L2CAP protocol layer resides the TCS module supporting cordless telephony and intercom profiles.

Wifi vs bluetooth osi model