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Chapter 4
OSPF Areas
Configuring OSPF--Single Area (NBMA Environment)
Previously, we mentioned three different possible ways to configure NBMA
network interfaces. They are:
Broadcast
Non-broadcast
Point-to-multipoint (a version of point-to-point)
We'll outline all three methods in this section. The key configuration
statement that is common to all configuration methods is the ip ospf
network
command.
The command has the options of specifying broadcast, non-broadcast,
and point-to-multipoint network types. The IOS senses the media type for all
interfaces and assigns the default network type accordingly. If you wish to
change that assignment, you would do so via the ip ospf network
command.
Broadcast Configuration
A full mesh among all OSPF routers is required for this environment to be
configured and work properly. A full explanation of the PVC configuration
is beyond the scope of this chapter, but here is a sample configuration:
RouterA#conf t
Enter configuration commands, one per line. End with
CNTL/Z.
RouterA(config)#int serial 1
RouterA(config-if)#ip ospf network broadcast
RouterA(config-if)#encapsulation frame-relay
RouterA(config-if)#frame-relay map ip 172.16.11.2 102
broadcast
RouterA(config-if)#frame-relay map ip 172.16.11.3 103
broadcast
RouterA(config-if)#frame-relay map ip 172.16.11.4 104
broadcast
RouterA(config-if)#router ospf 1
RouterA(config-router)#network 172.16.11.0 0.0.0.255
area 0
RouterA(config-router)#^Z
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