| 802.15.4 Header | 6lowpan | AM type | data | 802.15.4 CRC |
+-------------------+---------+------------------------------+--------------+
-AM type is the same as in a T-frame. 6lowpan is the NALP code to identify
-this as a TinyOS packet. NALP codes must be in the range of 0-63.
-TinyOS uses code 63.
+AM type is the same as in a T-frame. 6lowpan is the NALP code to
+identify this as a TinyOS packet. NALP codes must be in the range of
+0-63. TinyOS uses code 63 (0x3F).
The AM type 63 is reserved for both T-Frames and I-Frames. A TinyOS
program MUST NOT use it.