What is ARP (allocation and retention priority)?

It indicates a priority level for the allocation and retention of bearers. The mobile network uses ARP to decide whether to accept a request to establish a bearer or reject the bearer when resources are limited. It is related to the QoS of the EPS bearer. When performing admission control and network resources are limited, the network uses the ARP to prioritize establishing or modifying bearers with a higher ARP over bearers with a lower ARP.

In a 4G network, ARP priority level (PL) values range from 1 through 15, where 1 is at highest priority and 15 at lowest priority. In a 3G network, its value range from 1 to 3, where 1 is at the highest priority and 3 at lowest priority.