Zigbee MAC layer frames

As mentioned in the zigbee protocol stack that zigbee MAC layer frame composed of MAC header,MAC payload and FCS. The diagram below depicts generic mac frame format adopted in zigbee technology at MAC layer. This part is also referred as MPDU or MAC Protocol Data Unit. This gets embedded into PPDU(physical PDU) frame of zigbee.

Generic MAC Frame format

Octets:2 1 0/2 0/2/8 0/2 0/2/8 Var 2
Frame control Sequence number Destination PAN ID Destination Address Source PAN ID Source Address Frame Payload FCS
Addressing fields
MHR MAC Payload MFR

Generic MAC layer frame has frame control field of 2 octets. It carries useful information such as frame type, source and destination addressing modes. Frame type specifies whether the frame is beacon frame,data frame, ACK of data, MAC command frame etc. The same is outlined 'Frame type subfield' table below with 3 bits.

Frame control field

Bits:
0-2
3 4 5 6 7-9 10-11 12-13 14-
15
Frame
type
security
enabled
Frame
pending
Ack.
Request
Intra
PAN
Reserved Dest.
Addre-
ssing
mode
Reserved Source
Addre-
ssing
mode

Frame type subfield

Frame type
value
(b2,b2,b0)
Description
000 Beacon
frame
001 Data
frame
010 Acknowledgement
011 MAC
command
100-111 Reserved

As shown below beacon frame carries frame control field and addressing fields along with sequence number. It is broadcasted to obtain PAN ID of nearby zigbee devices.

Beacon Frame format

Octets:2 1 4/10 2 var var var 2
Frame
control
sequence
number
Addressing
fields
Superframe
specification
GTS fields Pending
address
fields
Beacon
payload
FCS
MHR MAC Payload MFR

Once connection is established data frame carry data. The format of data frame is similar to generic mac frame format and is shown in the table below.

Data Frame format

Octets:2 1 section
7.2.2.2.1
IEEE
802.15.4
Variable 2
Frame
control
sequence
number
Addressing
fields
Data
Payload
FCS
MHR MAC Payload MFR

Acknowledgement Frame format

Octets:2 1 2
Frame control sequence number FCS
MHR MFR

MAC command Frame format

Octets:2 1 section 7.2.2.4.1 IEEE 802.15.4 1 Variable 2
Frame control sequence number Addressing fields Command Frame Identifier Command Payload FCS
MHR MAC Payload MFR

Zigbee protocol supports different command frames for difference use case as mentioned below in the table.

MAC command frames

Command Frame ID Command frame
0x01 Association request(Tx)
0x02 Association response(Rx)
0x03 Disassociation notification(Tx,Rx)
0x04 Data request(Tx)
0x05 PAN ID conflict notification(Tx)
0x06 Orphan notification(Tx)
0x07 Beacon request(Tx)
0x08 coordinator realignment(Rx)
0x09 GTS Request
0x0a-0xFF Reserved

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