Lab 19. OSPF - Timers

Konfigurasikan OSPF pada setiap router

R1(config)#router ospf 1
R1(config-router)#network 12.12.12.0 0.0.0.255 area 0
R1(config-router)#network 1.1.1.1 0.0.0.0 area 0

R2(config)#router ospf 2
R2(config-router)#network 12.12.12.0 0.0.0.255 area 0
R2(config-router)#network 23.23.23.0 0.0.0.255 area 0
R2(config-router)#network 2.2.2.2 0.0.0.0 area 0

R3(config)#router ospf 3
R3(config-router)#network 23.23.23.0 0.0.0.255 area 0
R3(config-router)#network 3.3.3.3 0.0.0.0 area 0

Cek hello timer dan dead interval secara defulat pada ospf interface, dengan perintah

R1#show ip ospf int e0/0
Ethernet0/0 is up, line protocol is up
Internet Address 12.12.12.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 10
Topology-MTID Cost Disabled Shutdown Topology Name
0 10 no no no Base
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 12.12.12.2 Backup Designated router (ID) 1.1.1.1, Interface address
12.12.12.1
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit
5

Rubah Hello Interval nya

R1(config)#int e0/0
R1(config-if)#ip ospf hello-interval 20

Ketika hello interval di rubah yang terjadi adalah dead time juga ikut berubah menjadi 4x nilai hellonya namun tidak berlaku sebaliknya.cek kembali OSPF timernya

R1#show ip ospf int e0/0
Ethernet0/0 is up, line protocol is up
Internet Address 12.12.12.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 10
Topology-MTID Cost Disabled Shutdown Topology Name
0 10 no no no Base
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 12.12.12.2 Backup Designated router (ID) 1.1.1.1, Interface address
12.12.12.1
Timer intervals configured, Hello 20, Dead 80, Wait 40, Retransmit
5

Akan muncul pesan seperti ini

*Jun 7 06:49:27.836: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Ethernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired

kita coba samakan, rubah dead timer nya pada R2 eth0/0

R2(config)#int e0/1
R2(config-if)#ip ospf hello-interval 20

akan terjadi adjency, nah disini kita tahu bahwasannya syarat hello timer pada OSPF yaitu harus sama antar eth.sekarang kita coba rubah dead intervalnya menjadi 30 detik

R2(config)#int e0/1
R2(config-if)#ip ospf dead-interval 30

R3(config)#int e0/0
R3(config-if)#ip ospf dead-interval 30

jika dead interval dirubah hello timer akan mengukuti dead interval yang kita set.

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