When the length of Application Layer (APL) data packets is greater than the maximum limit
of the APL payload, the stack fragments the entire data into blocks.Figure 5-12. Fragmentation – Relevant
Header Information
The following figure illustrates the fragmentation example.
Figure 5-13. Fragmentation – Example
The sender node sends the first fragment with the block number as the total number of
blocks comprising the entire APL data. The subsequent fragments have block numbers
starting from one going up to the maximum transmission window size. The receiving node
sends an APS acknowledgment frame after receiving all blocks in the transmission window.
For more details, refer to the Zigbee Specification Revision 22 1.0 (05-3474-22).
