* C: Congestion notification. If a node drops a CTP data frame, it MUST set the C field on the next data frame it transmits.
* THL: Time Has Lived. When a node generates a CTP data frame, it MUST set THL to 0. When a node receives a CTP data frame, it MUST increment the THL. If a node receives a THL of 255, it increments it to 0.
* ETX: The ETX routing metric of the single-hop sender. When a node transmits a CTP data frame, it MUST put the ETX value of its route through the single-hop destination in the ETX field. If a node receives a packet with a lower gradient than its own, then it MUST schedule a routing frame in the near future.
* C: Congestion notification. If a node drops a CTP data frame, it MUST set the C field on the next data frame it transmits.
* THL: Time Has Lived. When a node generates a CTP data frame, it MUST set THL to 0. When a node receives a CTP data frame, it MUST increment the THL. If a node receives a THL of 255, it increments it to 0.
* ETX: The ETX routing metric of the single-hop sender. When a node transmits a CTP data frame, it MUST put the ETX value of its route through the single-hop destination in the ETX field. If a node receives a packet with a lower gradient than its own, then it MUST schedule a routing frame in the near future.