HAP
The Host Access Protocol (HAP) is a network layer protocol that defines the different types of host-to-network control messages and host-to-host data messages that may be exchanged over the access link connecting a host and the network packet switch node. The protocol establishes formats for these messages, and describes procedures for determining when each type of message should be transmitted and what it means when one is received.
Available to all SRX running 12.3X48+
Available to all MX running 20.2R1+
Available to all vSRX running 20.3R1+