If the device at the other end of a circuit does not support InARP, static mapping is required for that circuit. One of these two methods must be used to generate an ARP table entry for each circuit of the NBMA interface.
InARP and static mapping are complementary within an NBMA subinterface, but are not compatible with regard to individual circuits. If InARP is configured on a circuit, the corresponding virtual circuit descriptor (VCD) cannot be present in a static map applied to that interface.