3Com 3032 Configuration Manual page 445

Configure DR on OSPF
Preference
c Configure the area-id of the interface and the interface type
[RouterC-ospf] quit
[RouterC] interface serial 0
[RouterC-Serial0] ospf enable area 0
[RouterC-Serial0] ospf network-type p2mp
[RouterC-Serial0] ospf peer 1.1.1.1
[RouterC-Serial0] ospf peer 1.1.1.2
4 Configure Router D:
a Configure the ip address of interface Serial0, encapsulated into frame relay and
configure frame relay mapping table.
[RouterD] interface serial 0
[RouterD-Serial0] ip address 1.1.1.4 255.0.0.0
[RouterD-Serial0] link-protocol fr
[RouterD-Serial0] fr map IP 1.1.1.5 dlci 401 broadcast
b Enable OSPF
[RouterD] router id 4.4.4.4
[RouterD] ospf enable
[RouterD-ospf] quit
c Configure the area-id of the interface and the interface type
[RouterD-Serial0] ospf enable area 0
[RouterD-Serial0] ospf network-type p2mp
[RouterD-Serial0] ospf peer 1.1.1.5
5 Configure Router E:
a Configure the ip address of interface Serial0, encapsulated into frame relay and
configure frame relay mapping table.
[RouterE] interface serial 0
[RouterE-Serial0] ip address 1.1.1.5 255.0.0.0
[RouterE-Serial0] link-protocol fr
[RouterE-Serial0] fr map IP 1.1.1.1 dlci 501 broadcast
[RouterE-Serial0] fr map IP 1.1.1.4 dlci 502 broadcast
b Enable OSPF
[RouterE-Serial0] quit
[RouterE] router id 5.5.5.5
[RouterE] ospf enable
c Configure the area-id of the interface and the interface type
[RouterE-ospf] quit
[RouterE] interface serial 0
[RouterE-Serial0] ospf enable area 0
[RouterE-Serial0] ospf network-type p2mp
[RouterE-Serial0] ospf peer 1.1.1.1
[RouterE-Serial0] ospf peer 1.1.1.4
I. Networking requirement
The following example describes the configuration of route preference of several
routers in an OSPF autonomous system. The preference of Router A is 100, the
highest on the network, therefore Router A is selected as DR. Router C is of the
second highest priority, therefore is chosen as BDR. The preference of Router B is
0, which means that it cannot be a DR. Router D has no preference, so the default
value 1 is taken.
OSPF Configuration Example 441