There are two types of piconet Topology, one is BR/EDRtopology and the other is LEtopology.
BR/EDR Topology
Two or more devices working on the same physical channel are connected to each other to form a piconet .
A piconet consists of a master and multiple slaves.
The master provides a reference for the clock and frequency hopping mode to desynchronize the slaves.
There may be multiple piconets in an area, and each piconet uses a different physical channel.
A device cannot act as a master in two piconets (if it can, then the two piconets will work on the same channel).
A device can act as a slave in several different piconets.
A device is in one piconet and in another piconet, then the device is in scatternet .
The Bluetooth core system does not provide such a function, which is implemented by the upper layer protocol.
In Figure 4.1 an example topology is shown that demonstrates a number of the
architectural features described below. Device A is a master in a piconet
(represented by the shaded area, and known as piconet A) with devices B, C,
D and E as slaves. Three other piconets are shown: a) one piconet with device
F as master (known as piconet F) and devices E, G and H as slaves, b) one
piconet with device D as master (known as piconet D) and device J as slave,
and c) one piconet with device M as master (known as piconet M) and device E
as a slave and many devices N as slaves.
In piconet A there are two physical channels. Devices B and C are using the
basic piconet physical channel (represented by the blue enclosure) as they do
not support adaptive frequency hopping. Devices D and E are capable of
supporting adaptive frequency hopping, and are using the adapted piconet
physical channel (represented by the red enclosure). Device A is capable of
adaptive frequency hopping, and operates in a TDM basis on both physical
channels according to which slave is being addressed.
Piconet D and piconet F are both using only a basic piconet physical channel
(represented by the cyan and magenta enclosures respectively). In the case of
piconet D this is because device J does not support the adaptive hopping
mode. Although device D supports adaptive hopping it cannot use it in this
piconet. In piconet F device F does not support adaptive hopping, and
therefore it cannot be used in this piconet.
Piconet M (represented by the orange enclosure) uses a Connectionless Slave
Broadcast physical link over the adaptive piconet physical channel to send
Profile Broadcast Data to many slave devices including E and N.
Piconet M (represented by the orange enclosure) uses a Connectionless Slave
Broadcast physical link over the adaptive piconet physical channel to send
Profile Broadcast Data to many slave devices including E and N.
Device L is shown in the same locality as the other devices. It is not currently a
member of a piconet, but is currently listening on its Synchronization scan
physical channel (represented by the brown enclosure), awaiting a
synchronization train from another device.
LE Topology
In Figure 4.2 an example topology is shown that demonstrates a number of the
LE architectural features described below. Device A is a master in a piconet
(represented by the shaded area, and known as piconet A) with devices B and
C as slaves. Unlike BR/EDR slaves, LE slaves do not share a common
physical channel with the master. Each slave communicates on a separate
physical channel with the master. One other piconet is shown with device F as
master (known as piconet F) and device G as a slave. Device K is in a
scatternet (known as scatternet K). Device K is master of device L and slave of
device M. Device O is also in a scatternet (known as scatternet O). Device O is
slave of device P and slave of device Q. Note: in the figure, solid arrows point
from master to slave; dashed arrows, indicating a connection initiation, point
from initiator to advertiser using a connectable advertising event; devices that
are advertising are indicated using stars.
There are five other groups of devices shown:
1. Device D is an advertiser and device A is also an initiator (known as group D).
2. Device E is a scanner and device C is also an advertiser (known as group C).
3. Device H is an advertiser and devices I and J are scanners (known as group H).
4. Device K is also an advertiser and device N is an initiator (known as group K).
5. Device R is an advertiser and device O is also an initiator (known as group R).
Devices A and B are using one LE piconet physical channel (represented by
the blue enclosure and a dark gray background). Devices A and C are using
another LE piconet physical channel (represented by the blue enclosure and a
lighter gray background). In group D, device D is advertising using a
connectable advertising event on the advertising physical channel
(represented by the green enclosure) and device A is an initiator. Device A can
form a connection with device D and add the device to piconet A. In group C,
device C is also advertising on the advertising physical channel (represented
by the orange enclosure) using any type of advertising events that are being
captured by device E as a scanner. Group D and group C may be using
different advertising PHY channels or different timings to avoid collisions.
In piconet F, there is one physical channel. Devices F and G are using an LE
piconet physical channel (represented by the aqua enclosure). Device F is the
master and device G is the slave.
In group H, there is one physical channel. Devices H, I and J are using an LE
advertising physical channel (represented by the purple enclosure). Device H
is an advertiser and devices I and J are scanners.
In scatternet K, devices K and L are using one LE piconet physical channel.
Devices K and M are using another LE piconet physical channel. In group K,
device K is also advertising using a connectable advertising event on the
advertising physical channel and device N is an initiator. Device N can form a
connection with device K resulting in device K being slave of two devices and
master of one device at the same time.
In scatternet O, devices O and P are using one LE piconet physical channel.
Devices O and Q are using another LE piconet physical channel. In group R,
device R is advertising using a connectable advertising event on the
advertising physical channel and device O is an initiator. Device O can form a
connection with device R resulting in device O being slave of two devices and
master of one device at the same time.
More
For more content reference: Bluetooth learning summary