HNB Subsystem is defined in TS 23.060
. According to the definition, a HNB subsystem consists of a HNB and a HNB GW. The HNB Subsystem appears as an RNS to the core network and is connected by means of the Iu-CS interface to the MSC and by means of the Iu-PS interface to the SGSN.
Detailed functions of HNB and HNB GW are described in TS 25.467
. To be more specific, HNB is a Customer Premise Equipment that offers the Uu Interface to the UE. It provides RAN connectivity and supports RNC like functions as well as UE registration over Iuh. HNB Gateway (HNB-GW) terminates Iuh from HNB and appears as an RNC to the existing Core network using existing Iu interface. It supports HNB registration and UE registration over Iuh.
Based on the above characteristics, this specification defines respective HNS NRM IRP requirements.
The following general and high-level requirements apply for the present IRP:
The NRM defined by this IRP:
Shall support communications for telecommunication network management purposes, including management of converged networks.
Is a member of the Federated Network Information Model (FNIM)  and its information is derived from FNIM Umbrella Information Model (UIM) 
In addition to the above, the following more specific requirements apply:
The Network Resource Model defined by this IRP shall contain HNB GW specific IOCs and related definitions.
The Network Resource Model defined by this IRP shall provide support for enabling consistency between HNB GW, HNB and related core network nodes.
The NRM specified by this IRP shall be able to view configuration information of the HNB GW entity. More detailed information is as follows:
Shall allow for the viewing of basic configuration information including version, equipment type, equipment provider and unique identification, etc.
Shall allow for the viewing of network configuration information including IP address, sub-network mask, default gateway and port configuration information, etc.
Shall allow for the viewing of service related configuration information, for example the maximum number of HNB to be registered, the maximum number of packets to be forwarded, etc.
The NRM specified by this IRP shall capture Iuh interface information of HNB GW. More detailed information is as follows:
Shall allow for the viewing of basic configuration information including Iuh identification etc.
Shall allow for the viewing of network configuration information including SCTP management information, etc.
The NRM specified by this IRP shall capture the identity of registered HNB.