NBMA Networks are Frame-Relay, ATM & X.25 networks.
Multiple devices are attached but are non-broadcast.
Question
Configure OSPF on R3, R4, R5 and R6 such as no DR election occurs.
Set the network type to 'point-to-multipoint'.
The DLCI is treaten as point-to-point link, so no DR/BDR election occurs.
OSPF packets are still multicast.
On R3:
!
interface Serial1/0.3456 multipoint
ip address 100.3.0.3 255.255.255.0
ip ospf network point-to-multipoint
frame-relay interface-dlci 304
frame-relay interface-dlci 305
frame-relay interface-dlci 306
!
router ospf 1
router-id 100.1.3.1
log-adjacency-changes
network 100.3.0.3 0.0.0.0 area 0
!
On R4:
!
interface Serial1/0.3456 multipoint
ip address 100.3.0.4 255.255.255.0
ip ospf network point-to-multipoint
frame-relay interface-dlci 403
!
router ospf 1
router-id 100.1.3.1
log-adjacency-changes
network 100.3.0.4 0.0.0.0 area 0
!
and so on for R5 and R6.
No DR/BDR election occurs:
R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
100.1.5.9 0 FULL/ - 00:01:37 100.3.0.5 Serial1/0.3456
100.1.4.1 0 FULL/ - 00:01:57 100.3.0.4 Serial1/0.3456
100.1.6.1 0 FULL/ - 00:01:56 100.3.0.6 Serial1/0.3456
