 DHCP messages. 3.1 The IEEE 802.1 16m reference model security context management, radio resource management, and low power operations such as idle mode and paging functions. 3.1.2 Network Control and Management System The Network Control and Management System is not part of the IEEE 802.16 standards, and is treated as a "black box." It may be distributed with components residing on different nodes in a network. Part of the NCMS may be physically collocated with the IEEE 802.16 entity referred to as NCMS-E. The remaining part of the NCMS may be physically distributed across one or more network entities. This part of the NCMS is referred to as NCMS-N. Figure 3-5 shows the partitioning of the NCMS into NCMS-E and NCMS-N. The NCMS-E may have its own software platform and network protocol implementation, allowing it to communicate with external entities in the NCMS-N. The NCMS-E may provide an SNMP Agent compliant to IETF RFC3418 [13] and the SNMP/TCP/IP protocol stack, to allow for interactions with an SNMP manager. The NCMS-E may provide an Object Request Broker and implement a protocol stack to interact with components on other network entities within NCMS-N based CORBA architecture. iv The messages available to a manager in the NCMS-N are specified using Interface Description Language (IDL). These messages encapsulate the interactions with the MIB. The IEEE 802.16 entity can be managed through Web Services. vi [11] The decomposition of Network Control and Management System is depicted in Figure 3-6. These entities may be centrally located or distributed across the network. The exact functionality of these entities and their services is outside the scope of the IEEE 802.16 standard, but is shown here for illustration purposes and to allow description of the management and control procedures. The NCMS service manifestations on the MS and BS may have different configurations and functions. The IEEE 802.16m reference model is very similar to that of the IEEE 802.16-2009 standard, with the exception of soft classific