How to Configure OSPF Multiaccess Broadcast

 

Configure Multiarea OSPF in CIsco

R1 Initial Contigure

R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#int e0/0
R1(config-if)#no sh
R1(config-if)#ip add
R1(config-if)#ip address
*Apr 4 10:30:32.875: %LINK-3-UPDOWN: Interface Ethernet0/0, changed state to up
*Apr 4 10:30:34.159: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to up
R1(config-if)#ip address 10.1.1.1 255.0.0.0

R1(config-if)#ip ospf 10 area 0

R2 Initial Contigure

R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#int e0/0
R2(config-if)#no sh
R1(config-if)#ip add
R2(config-if)#ip address
*Apr 4 10:30:32.875: %LINK-3-UPDOWN: Interface Ethernet0/0, changed state to up
*Apr 4 10:30:34.159: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to up
R2(config-if)#ip address 20.1.1.1 255.0.0.0

R2(config-if)#ip ospf 10 area 0

R3 Initial Contigure

R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#int e0/0
R3(config-if)#no sh
R3(config-if)#ip add
R3(config-if)#ip address
*Apr 4 10:30:32.875: %LINK-3-UPDOWN: Interface Ethernet0/0, changed state to up
*Apr 4 10:30:34.159: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to up
R3(config-if)#ip address 30.1.1.1 255.0.0.0

R3(config-if)#ip ospf 10 area 0

Verification :  
The DR & BDR election can be verified by using the following commands
R2#show ip ospf neighbor
R3#show ip ospf interface
      •     Routers notify DR on 224.0.0.6
      •     DR notifies others on 224.0.0.5.
      •     Router with highest priority value is the DR
      •     Router with second highest priority value is BDR
      •     Default for interface OSPF priority is 1
      •     In case of a tie, router-id (highest) is preferred
      •     A router with priority set to 0 cannot become the DR/BDR and is called DR other
      •     DR election is non-preemptive
Setting priority for DR election
(config-if) # ip ospf priority number
                                    -Default is 1
                                    -Range is 0-255.

Related posts

Leave a Comment