Bluetooth Profiles : LAN Access and PAN Profiles

Bluetooth LAN Access or PAN profile
Figure: LAN Access or PAN Profile
Bluetooth devices access a LAN via a Bluetooth access point.
If one computer is part of a LAN, it can be used as an access point.

Local Area Network Access Profile (LAP)

LAN Access profile enables a Bluetooth device to access a LAN, WAN, or Internet via another Bluetooth device that has physical connection to the LAN/WAN/Internet. This profile uses PPP (Point-to-Point Protocol) over RFCOMM (emulation of serial cable) for connection establishment. LAP also allows a Bluetooth device to join a Bluetooth ad-hoc network.
The LAN Access Profile is replaced by PAN profile in the new Bluetooth specification. But it is still widely supported by many legacy Bluetooth products.

Personal Area Networking (PAN) Profile

PAN profile allows a Bluetooth device to join a piconet (Personal Area Network) and access LAN resources or WAN (e.g. PSTN, ISDN, GSM, GPRS, CDMA, EV-DO, Internet) via a Bluetooth Network Access Point (NAP). A Bluetooth Network Access Point (NAP) functions as a bridge, router, or proxy that enables connection between Bluetooth devices and a LAN, WAN, or the Internet. Typically, a Bluetooth access point is designed to serve small computing devices that require network access with low power consumption, i.e. handhelds (PDAs) and mobile phones. But, it may also support laptop or desktop computers and other Bluetooth-enabled devices.

PAN profile defines three device roles, i.e. NAP, GN (Group ad-hoc Network), and PANU (PAN User). As a NAP, a Bluetooth device provides access for up to 7 active PANUs to a LAN or WAN. As a GN, a Bluetooth device interconnects up to 7 active PANUs in a group ad-hoc network (piconet). As a PANU, a Bluetooth device can access LAN/WAN via a NAP, join a PAN (piconet) via a GN, or directly connect to another PANU.

NAP, GN, and PANU roles in Bluetooth PAN profile
Figure: NAP, GN, and PANU roles in PAN profile
NAP connects the piconet to other network.
GN does not provide connection to other network.
PANU is a client to NAP or GN. Two PANUs can communicate directly.

In PAN profile, data (Ethernet) packets are encapsulated using BNEP (Bluetooth Network Encapsulation Protocol) when transferred between Bluetooth devices, therefore it is more bandwidth efficient and faster than LAN Access Profile which requires the establishment of a point-to-point link for each connection between two Bluetooth devices. In addition, the PAN profile also fully supports Internet Protocol (both IPv4 and IPv6) enabling all IP-based services to run over Bluetooth.

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