Configuring IP Addressing
IP Addressing Examples
IPC-52
Cisco IOS IP Configuration Guide

Figure9 Two Logical NBMA Networks over One Physical NBMA Network

The physical configuration of the five routers in Figure9 might actually be that shown in Figure 10. The source host is connected to Router A and the destination host is connected to Router E. The same switch serves all five routers, making one physical NBMA network.
Router E
Destination
host
Router C
Router D
Router A
Router B
Source
host
ip nhrp network-id 7
ip nhrp network-id 7
ip nhrp network-id 2
ip nhrp
network-id 2
ip nhrp network-id 2
ip nhrp network-id 7
= Statically configured tunnel endpoints or permanent virtual circuits
= Dynamically created virtual circuits
S3230