7.3 Piconets and the Master/Slave Concept
As previously described, all devices that communicate with each other for a certain time form a piconet. As shown in Figure 7.2, the frequency hopping sequence of the channel is calculated from the hardware address of the first device that initiates a connection to another device and thus creates a new temporary piconet. Therefore, devices can communicate with each other in different piconets in the same area without disturbing each other.
A piconet consists of one master device that establishes the connection and up to seven slave devices. This seems to be a small number at first. However, as most Bluetooth applications only require point-to-point connections as described in Section 7.1, this limit is sufficient for most applications. Even if Bluetooth is used with a PC to connect with a keyboard and a mouse, there are still five more devices that can join the PC's piconet at any time.
Each device can be a master or a slave of a piconet. Per definition, the device that initiates a new piconet becomes the master device as described in the following scenario.
Consider a user who has a Bluetooth-enabled mobile phone and headset. After initial pairing (see Section 7.5.1), the two devices can establish contact with each other at any time and thus form ...