Format of individual frame types

Four frame types are defined : beacon, data, acknowledgment, and MAC command.

1. Beacon Frame Format :
used by a coordinator to transmit beacons.
Figure of formatted beacon frame.
f44.jpg

Figure of formatted GTS fields :
f45.jpg

Figure of formatted Pending Address Fields :
f46.jpg

The order of the fields of the beacon frame shall conform to the order of the general MAC frame frame as illustrated

in this Figure .

1.1 Beacon frame MHR fields :
MHR for a beacon frame contain the frame control field, the sequence number field, the source PAN Identifier field,
and the source address field.
In the Frame Control field, the Frame Type subfield contain the value(000) that indicates a beacon frame,as shown in this
table , and the source addressing mode subfield shall be set as appropriate for the address of the coordinator transmitting the beacon frame.

The Sequence Number field contain the current of macBSN (BSN = Beacon Sequence Number).

The addressing fields comprise only the source address fields. The source PAN identifier and source address fields contain the PAN identifier and address, respectively, of the device transmitting the beacon.

The Auxiliary Security Header field, if present, contain the information required for security processing of the beacon frame.

1.2 Superframe Specification Field.
The superframe specification field is 2 octets (16 bits) in length. This the figure of Superframe specification field.
f47.jpg

The beacon order subfield is 4 bits in length and specify the transmission interval of the beacon.

The Superframe Order subfield is 4 bits in length and specify the length of time during which the superframe is active.

the Final CAP (Contention Access Period) slot subfield in 4 bits in length and specifies the final superframe slot utilized by the CAP. The duration of the CAP shall be greater than or equal to the value specified by aMinCAPLength.

However, an exception is allowed for the accommodation of the temporary increase in the beacon frame length needed to perform GTS maintenance.

The Battery Life Extension (BLE) subfield is 1 bit in length and shall be set to one if frames transmitter to the beaconing device during its CAP are required to start in.

The PAN coordinator subfield is 1 bit in length and shall be set to one if the beacon frame is being transmitted by the PAN coordinator.

The Association Permit subfield is 1 bit in length and shall be set to one if macAssociation Permit is set to TRUE (maksudnya jika kordinator mau menerima device lain sebagai anggota jaringannya). The assocation permit bit shall be
set to zero if the coordinator is currently not accepting association request on its network.

1.3 GTS specifications Field.
The GTS specification field is 8 bits in length, this is figure of formatted GTS specification field.
f47.jpg
The GTS descriptor count subfield is 3 bits in length and specifies the number of 3 -octet GTS descriptors contained in the GTS list field of the beacon frame (read standard to know more about this).

The GTS permit subfield is 1 bit in length and shall be set to one if macGTSPermit is equal to TRUE (for example : the PAN coordinator is accepting GTS requests).

1.4 Pending Address Specification field :
This is the figure of formatted Pending Address specification field.

2. Data Frame Format :
used for all transfers of data.
This is the figure of Data frame :
f52.jpg

2.1 Data Frame MHR field.
The MHR for a data frame shall contain the frame control field, the sequence number field, the destination PAN identifier/address field, and / or the source PAN identifier/address fields.

In frame control field, the frame type subfield shall contain the value that indicates a data frame.

The Sequence number field shall contain the current value of macDSN (DSN = data sequence number).

The addressing fields shall comprise the destination address fields and/or the source address fields.

The Auxiliary Security header field, if present, shall contain the information required for security processing of the data frame.

2.2 Data Payload field.
The payload of a data frame shall contain the sequence of octets that the next higher layer has requested the MAC
sublayer to transmit.

3. Acknoledgment frame Format :
this is the figure of acknoledgment frame format
f53.jpg

3.1 Acknowledgment frame MHR fields.
The MHR contain only Frame Control field and the sequence number field.

In the frame control field, the frame type subfield shall contain value (010) that indicates an acknowledgment frame.

The sequence number field shall contain the value of the sequence number received in the frame for which the acknowledgment is to be sent.


4. MAC command frame format

used for handling all MAC peer entity control.
This is figure of MAC command frame.
f54.jpg

4.1 MAC command frame MHR fields
The MHR shall contain the frame control field, the sequence number field, the destination PAN identifier/address
fields and/or the source PAN identifier/address fields.

In the Frame Control field, the frame Type subfield shall contain the value (011) that indicates a MAC command
frame.

The sequence number field shall contain the current value of macDSN.

The addressing fields comprise the destination address fields and/or the source address fields.

The auxiliary security header field, if present, contain the information required for security processing of the MAC
command frame.

4.2 Command Frame Identifier Field.
The command frame identifier identifies the MAC command being used. this field shall be set to one of the
nonreserved values listed in this table :
t82.jpg

4.3 command Payload field.
The command payload field contains the MAC command itself. the formats of the individual commands will be described
in the following section.

Reference :
IEEE Standard for Information technology, Specifications for WPANs 802.15.4

you must find your own research style by yourself,

January 28 2008 – Winter Vacation,
Taipei City
High Speed Network Lab

Udin Harun

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