This read-write INTEGER (unspecified(-1), host(1), router(2)) in the ND inspection policy table specifies the expected role of the device attached to a port or VLAN using this policy. An admin cares because ND inspection enforces different rules depending on role -- a host-role port should never legitimately send router-type neighbor discovery traffic, so setting it correctly is what lets ND inspection tell normal from malicious traffic. For example, setting this to host(1) for policy "ndi-access" on an access port ensures ND inspection treats any router-role ND traffic arriving there as suspicious.