|- Receiver-Abort Header -|
+---------------------------------+-----------------+---------+
| RuleID | W=b'11 | C=b'1 |  b'11 |  0xFF (all 1's) | b'0-pad |
+--------+--------+-------+-------+-----------------+---------+
| 3 bits | 2 bits | 1 bit | 2 bit |  8 bit          | 48 bits |
          next L2 Word boundary ->| <-- L2 Word --> |