Lab OSPF: Cấu hình DR-BDR-DRO
Cho sơ đồ như sau:
Các câu lệnh show:
show ip protocols
show ip ospf
show ip ospf interface
show ip ospf neighbor
show ip route
Cấu hình:
Nên cấu hình priority trước khi cấu hình OSPF!
Router có Priority cao nhất sẽ là DR, nhì là BDR, còn lại là DROther
- Default Priority là 1
- Router có Priority bằng nhau thì Router có Router-ID cao nhất là DR
Lưu ý: Priority=0 thì Router sẽ không tham gia bình bầu DR/BDR
Cách 1: Đổi priority
R1(config)#interface F0/1
R1(config-if)#ip ospf priority 100
R1(config-if)#end
R1# write
R2(config)#interface F0/1
R2(config-if)#ip ospf priority 50
R2(config-if)#end
R2# write
R3(config)#interface F0/1
R3(config-if)#ip ospf priority 1
R3(config-if)#end
R3# write
Cách 2: đổi Router-ID
router ospf 100
router-id 211.1.1.1
exit
Cách 3: Cấu hình Interface Loopback
Trên Switch:
Switch>en
Switch#conf t
Switch(config)#int range e0/0 - 2
Switch(config-if-range)#switchport
Switch(config-if-range)#end
Switch#write
Trên các router R1, R2, R3:
ip 192.168.1.11/24 192.168.1.1
ip 192.168.2.22/24 192.168.2.1
ip 192.168.3.33/24 192.168.3.1
en
conf t
hostname R1
int f0/0
no sh
ip add 192.168.1.1 255.255.255.0
exit
int f0/1
no sh
ip add 200.1.1.1 255.255.255.248
exit
do wr
en
conf t
hostname R2
int f0/0
no sh
ip add 192.168.2.1 255.255.255.0
exit
int f0/1
no sh
ip add 200.1.1.2 255.255.255.248
exit
do wr
en
conf t
hostname R3
int f0/0
no sh
ip add 192.168.3.1 255.255.255.0
exit
int f0/1
no sh
ip add 200.1.1.3 255.255.255.248
exit
do wr
Cấu hình OSPF:
router ospf 100
network 200.1.1.0 0.0.0.7 area 0
network 192.168.1.0 0.0.0.255 area 0
exit
do wr
router ospf 100
network 200.1.1.0 0.0.0.7 area 0
network 192.168.2.0 0.0.0.255 area 0
exit
do wr
router ospf 100
network 200.1.1.0 0.0.0.7 area 0
network 192.168.3.0 0.0.0.255 area 0
exit
do wr
Xem thông tin:
R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
200.1.1.3 1 FULL/DROTHER 00:00:39 200.1.1.3 FastEthernet0/1
201.2.2.2 1 FULL/BDR 00:00:31 200.1.1.2 FastEthernet0/1
R1#
R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
200.1.1.3 1 FULL/DROTHER 00:00:37 200.1.1.3 FastEthernet0/1
211.1.1.1 1 FULL/DR 00:00:37 200.1.1.1 FastEthernet0/1
R2#
R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
201.2.2.2 1 FULL/BDR 00:00:36 200.1.1.2 FastEthernet0/1
211.1.1.1 1 FULL/DR 00:00:33 200.1.1.1 FastEthernet0/1
R3#
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
200.1.1.0/29 is subnetted, 1 subnets
C 200.1.1.0 is directly connected, FastEthernet0/1
C 192.168.1.0/24 is directly connected, FastEthernet0/0
O 192.168.2.0/24 [110/20] via 200.1.1.2, 00:02:44, FastEthernet0/1
O 192.168.3.0/24 [110/20] via 200.1.1.3, 00:02:44, FastEthernet0/1
R1#