Techniques are described to provide ultra-reliability for cellular vehicle-to-everything (C-V2X) PC5 communications, including Network Assisted mode and Autonomous mode communications. In one example, a method includes receiving, by a radio unit of a system, a communication from a user equipment, such as a V2X-UE, wherein the communication comprises a data packet, a Layer 2 destination identifier, and an indication that the data packet is associated with a transmission type; determining whether transmission for the data packet is allowed for the transmission type; based on determining that transmission for the data packet is allowed for the transmission type, communicating a response to the UE, wherein the response provides a confirmation to the UE that the data packet was received by the radio unit and that the transmission type can be performed by the radio unit; and transmitting, by the radio unit, the data packet to one or more other UEs.