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基本設定
[Base config]
RT1
en
terminal length 0
conf t
hostname RT1
int gi0/0
ip address 10.0.0.1 255.255.255.0
no shut
exit
!
router ospf 1
router-id 1.1.1.1
network 10.0.0.0 0.0.0.255 area 0
end
!
RT2
en
terminal length 0
conf t
hostname RT2
int gi0/0
ip address 10.0.0.2 255.255.255.0
no shut
exit
!
router ospf 1
router-id 2.2.2.2
network 10.0.0.0 0.0.0.255 area 0
end
!
interval変更前
RT1#sh ip ospf int gi0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.0.0.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 10.0.0.2
Backup Designated router (ID) 1.1.1.1, Interface address 10.0.0.1
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:05
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 1 msec, maximum is 1 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 2.2.2.2 (Designated Router)
Suppress hello for 0 neighbor(s)Hello 10, Dead 40, Wait 40, Retransmit 5
retransmit-interval変更
RT1(config)#int gi0/0
RT1(config-if)#ip ospf retransmit-interval 10
RT1(config-if)#
RT1(config-if)#do sh ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 1 FULL/DR 00:00:34 10.0.0.2 GigabitEthernet0/0
RT1(config-if)#
RT1(config-if)#do sh ip ospf int gi0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.0.0.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 10.0.0.2
Backup Designated router (ID) 1.1.1.1, Interface address 10.0.0.1
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 10
oob-resync timeout 40
Hello due in 00:00:00
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 1 msec, maximum is 1 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 2.2.2.2 (Designated Router)
Suppress hello for 0 neighbor(s)再送間隔が変更されてもネイバー関係は継続することを確認。
hello-interval変更（retransmit-intervalを戻してから）
RT1(config-if)#ip ospf hello-interval 20
RT1(config-if)#
*May 24 15:15:25.458: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired
RT1(config-if)#
RT1(config-if)#do sh ip ospf neighbor #OSPFネイバーが存在しない
RT1(config-if)#do sh ip ospf int gi0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.0.0.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.1.1.1, Interface address 10.0.0.1
No backup designated router on this network
Timer intervals configured, Hello 20, Dead 80, Wait 80, Retransmit 5
oob-resync timeout 80
Hello due in 00:00:15
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 1 msec, maximum is 1 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
RT1(config-if)#
RT1(config-if)#ip ospf hello-interval 10
RT1(config-if)#
*May 24 15:16:19.641: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
RT1(config-if)#do sh ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 1 FULL/DR 00:00:31 10.0.0.2 GigabitEthernet0/0
RT1(config-if)#do sh ip ospf int gi0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.0.0.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 10.0.0.2
Backup Designated router (ID) 1.1.1.1, Interface address 10.0.0.1
Flush timer for old DR LSA due in 00:02:28
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:08
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 2 msec, maximum is 2 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 2.2.2.2 (Designated Router)
Suppress hello for 0 neighbor(s)・helloを10sから20sへ変更
・なんかdeadも40sから80sに変わってる
・helloが違っているのでネイバー解消、戻すと復活
dead-interval変更
RT1(config-if)#ip ospf dead-interval 80
RT1(config-if)#
*May 24 15:22:48.287: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired
RT1(config-if)#
RT1(config-if)#do sh ip ospf neighbor
RT1(config-if)#do sh ip ospf int gi0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.0.0.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.1.1.1, Interface address 10.0.0.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 80, Wait 80, Retransmit 5
oob-resync timeout 80
Hello due in 00:00:01
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 2 msec, maximum is 2 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
RT1(config-if)#
RT1(config-if)#ip ospf dead-interval 40
RT1(config-if)#
*May 24 15:24:39.755: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
RT1(config-if)#
RT1(config-if)#do sh ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 1 FULL/DR 00:00:33 10.0.0.2 GigabitEthernet0/0
RT1(config-if)#
RT1(config-if)#do sh ip ospf int gi0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.0.0.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 10.0.0.2
Backup Designated router (ID) 1.1.1.1, Interface address 10.0.0.1
Flush timer for old DR LSA due in 00:01:21
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:08
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 1 msec, maximum is 2 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 2.2.2.2 (Designated Router)
Suppress hello for 0 neighbor(s)・deadを変更してもhelloに変化はなかった
・deadの不一致でネイバー消滅、元に戻して復活は確認
疑問
・helloが変更されたときは4hello=1deadになるようdeadも自動で変わったけど、dead変更時にはhelloは特に変化がなかった。どういう挙動？
・ネットワークエンジニアとしてには「Dead値は、Hello値の常に4倍です。」と書かれているけれども、Dead変更時はhelloが変わらなかった。なんで？
・VRRPが3hello=holdなのは知ってる。
参考
Chapter: Configuring OSPF
OSPF – ip ospf hello-interval / ip ospf dead-interval