This glossary includes acronyms and terms which may be encountered in the Bluetooth® technology, and serves as a quick look-up guide.
Known Device A device for which at least the BD_ADDR is stored.
L
L Line status bits in an RFCOMM RLS commands. These are used
to signal overrun, parity, and framing errors on the RFCOMM channel.
L2CA Logical Link Control and Adaptation: the layer of the Bluetooth stack which implements L2CAP. This provides segmentation and re-assembly services to allow large packets to pass across Bluetooth links; also provides multiplexing for higher layer protocols and services.
L2CAP Logical Link Controller and Adaptation Protocol. This protocol
supports
higher level protocol multiplexing, packet segmentation and reassembly,
and the conveying of quality of service information.
L_CH Logical Channel.
LAN Local Area Network.
LAP LAN Access Point.
LAP Lower Address Part: 24 least-significant bits of a Bluetooth
address.
LC Link Controller. The Link Controller manages the link to the other
Bluetooth devices. It is the low-level baseband protocol handler.
LC Channel Link Control control channel. One of the 5 logical channels
defined for the Bluetooth system. It is mapped onto the packet header. It
control low level link control info. The LC is carried in every packet except
the ID packet which has no packet header.
LCP Link Controller Protocol.
LF Line Feed.
LFSR Linear Feedback Shift Register. Used in Bluetooth technology to generate
the HEC and CRC.
LIAC Limited Inquiry Access Code: an inquiry access code that
devices may agree to use for a short period in place of the General
Inquiry Access Code (GIAC).
Limited Discoverable A device is limited discoverable if it will respond to inquiries using the LIAC, but will not respond using the GIAC.
Link key The authentication key used to establish a link between
devices. See also bonding.
LM Link Manager. The Link Manager software entity carries out link
setup, authentication, link configuration, and other protocols.
LM Channel Link Manager control channel. One of the 5 logical channels
defined for the Bluetooth system. It carries control info exchanged between
the link managers of the master and the slave(s). It can be carried by either
the SCO or ACL link.
LMP Link Manager Protocol. The LMP is used for link setup and control.
The LMP PDU signals are interpreted and filtered out by the Link Manager
on the receiving side and are not propagated to higher layers.
LMP-authentication An LMP level procedure for verifying the identity
of a remote device. The
procedure is based on a challenge-response mechanism using a random number,
a secret key and the BD_ADDR of the non-initiating device. The secret key
used can be a previously exchanged link key or an initialization key created
based on a PIN (as used when pairing).
LMP-pairing A LMP procedure that authenticates two devices based
on a PIN and subsequently creates a common link key that can be used as
a basis for a trusted relationship or a (single) secure connection. The
procedure consists of the steps:
1: creation of an initialization key (based on a random number and a PIN),
2: LMP-authentication based on the initialization key and
3: creation of a common link key.
LocDev Local Device: the device at the near end of the Bluetooth
link. This term is used in documents dealing with service discovery.
Logical Channel There are 5 logical channels defined for the Bluetooth
system. The LC & LM control channels, and the UA, UI & US user channels.
The LC channel is carried in the packet header, all other channels are carried
in the packet payload. See the individual sections for more details.
LP Lower Protocol: often used as a generic label for lower layers
when an upper layer can be interfaced to more than one lower layer.
LSB Least Significant Bit.
M
M Master: the device that controls and coordinates a group of
Bluetooth devices (the controlled devices are known as Slaves). The
Master sets the frequency hop sequence, and decides when each slave
will be allowed to transmit.
M Mandatory: used when specifying which Bluetooth features a profile should support.
Maccess Number of repetitions of the access window. To increase reliability when messages are sent to parked Slaves in beacon slots, they can be repeated a number of times in successive access windows. So if Maccess has a high value, the parked Slaves are more likely to get a message; but of course, more bandwidth will be needed to send the message.
MAC Address 3-bit address to distinguish between units participating
in the piconet. Within Bluetooth technology, this is the AM_ADDR.
MAN Metropolitan Area Network.
MAPI Messaging Application Procedure Interface.master device A device
that initiates an action or requests a service on a piconet. Also the device
in a piconet whose clock and hopping sequence are used to synchronise all
other devices in the piconet.See also LocDev.
MIME Multiple Internet Mail Extension.
MIPS Mega-Instructions Per Second: a measure of processor speed.
Module A Bluetooth Module is a unit which implements the lower layers of the Bluetooth stack up to the Host Controller Interface (HCI). To make a complete Bluetooth device the module would need to be controlled by a host.
MMAC Multimedia Mobile Access Communication systems: a Japanese initiative to produce an ultra-high speed, high-quality Multimedia communications standard.
MMI Man Machine Interface
MS Mobile Station. A generic term for the mobile device in question
(GSM phone, Bluetooth device etc).
MSB Most Significant Bit.
MSC Message Sequence Chart.
MT Mobile Terminal, same as Mobile Station
MTU Maximum Transmission Unit: the largest size packet payload which a particular layer can handle. Used when referring to layers such as HCI and L2CAP, which can be implemented with different maximum packet sizes.
MUX Multiplexing Sublayer. A sublayer of the L2CAP layer.
N
Nacc-slots Number of Slave to Master access slots.
NACK Negative ACKnowledge: bit used to signal when a packet has been received with errors, or when a packet was expected and not received.
Name Discovery The mechanism to request and receive a device name.
NAP Non-significant Address Portion. A 16-bit section of the BD_ADDR.
See also LAP & UAP.
Nb Number of beacon slots within one beacon train.
Nb sleep Number of beacon train at which Slave wakes (it sleeps Nb sleep – 1 beacon trains).
NCRP National Council on Radiation Protection and measurements.
Non-connectable A device that does not responds to paging is said
to be in non-device connectable mode. The opposite of a non-connectable
device is a connectable device.
Non-discoverable A device that cannot respond to an inquiry is
said to be in non-device discoverable mode. The device will not enter
the inquiry response state in this mode.
Npoll Number of slots after the access window that a Slave listens after requesting unpark.
NRE Non-Recurring Expense: initial costs in product development.
NSC Non-Supportable Command: a response used by RFCOMM to initiate
that it has received a command that it does not support.
NT Network Terminal
NULL packet A 126-bit packet consisting of the CAC and packet header only. It is used to return link information to the source. The NULL packet does not have to be acknowledged .See also Bluetooth packet types.
O Optional: used when specifying which Bluetooth features a profile should support.
OBEX Object EXchange Protocol.
OCF OpCode Command Field: identifies an HCI command within a group
of commands.
OFDM Orthogonal Frequency Division Multiplexing
OGF OpCode Group Field: identifies a group of HCI commands.
OOBE Out Of Box Experience.
OpCode Operation Code: code used in signals to identify the type of information being carried in a message.
OS Operating System
OSI Operating System Interconnect