IBM RS/6000 - Manual (Page 184)

Figure 45. Sample Network Topology
The example above requires the definition of the following NIM objects:
NIM Master Fileset This object defines the network where the NIM Master is
connected to (network1). The Master machine object is
created automatically when the Master fileset object is
created.
Network3 This is a network object.
Standalone1 This is a machine object (NIM Client).
Additionally, two Network Install Route attributes, Gateway1 and Gateway2, must
be defined.
Note: Network2 is not immediately connected either to the NIM Master nor to the
NIM Client, and for this reason, it does not need to be defined in the NIM
160 Introduction to PCI-Based RS/6000 Servers