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OSPFの基本設定 – Cisco機器での設定方法

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OSPFの基本設定 - Cisco機器での設定方法

Cisco機器でのOSPFの基本設定方法を説明します。

OSPFの基礎知識や動作原理、エリアの考え方などについては下記を参照してください。

OSPFの概要と基礎知識
OSPFの動作原理 – ルーター間の情報交換とリンクステート広告
OSPFのアーキテクチャ – ネットワークの階層構造とエリア設計
目次

ネットワーク構成

下記のネットワーク構成を例にOSPFの基本設定について説明します。

ネットワーク構成

OSPFの基本設定

STEP
OSPFの有効化（OSPFプロセスの起動）
router ospf [Process ID]

プロセスIDは、[1-65535]の値で設定します。

設定例

OSPFの有効化
Router1(config)#router ospf 1
Router2(config)#router ospf 1
STEP
ルーターIDの設定
router-id [A.B.C.D]

ルーターIDは、IPアドレス形式で設定します。
ルーターIDは、OSPFネットワーク内で各ルーターを一意に識別するために使用されます。
手動で設定しない場合、下記の順番でルーターIDが決定されます。
① ループバックインターフェースのIPアドレス(一番大きな値)
② その他のインターフェースのIPアドレス(一番大きな値) ※アクティブなインターフェス

設定例

ルーターIDの設定
Router1(config-router)#router-id 100.100.100.254
Router2(config-router)#router-id 100.100.100.253
STEP
OSPFを有効化するインターフェースの指定
network [A.B.C.D] [wildcard-mask] area [Area-ID]

OSPFを有効化するインターフェースのネットワークを指定します。
エリアIDは、[0-4294967295]の値で設定します。※バックボーンエリアは「0」

設定例

OSPFを有効化するインターフェースの指定
Router1(config-router)#network 172.16.1.0 0.0.0.255 area 0
Router1(config-router)#network 192.168.1.0 0.0.0.255 area 0
Router2(config-router)#network 172.16.1.0 0.0.0.255 area 0
Router2(config-router)#network 192.168.2.0 0.0.0.255 area 0

ワイルドカードマスクについては、下記を参照してください。

サブネットマスク・ワイルドカードマスクの対応表と説明

OSPFの設定確認・ステータス確認

OSPFの設定やステータスは、下記のコマンドで確認できます。

show run | section router ospf
show ip ospf
show ip ospf neighbor
show ip ospf interface
show ip ospf database
show ip route
(show ip route ospf)

設定確認 – show run | section router ospf

OSPFの設定を確認するには下記のコマンドを実行します。

show run | section router ospf

コマンドの出力結果 – show run | section router ospf

Router1#show run | section router ospf
router ospf 1
 router-id 100.100.100.254
 network 172.16.1.0 0.0.0.255 area 0
 network 192.168.1.0 0.0.0.255 area 0
Router2#show run | section router ospf
router ospf 1
 router-id 100.100.100.253
 network 172.16.1.0 0.0.0.255 area 0
 network 192.168.2.0 0.0.0.255 area 0

設定したコンフィグが表示されます。

OSPF起動状況の確認 – show ip ospf

OSPFの起動状況を確認するには下記のコマンドを実行します。

show ip ospf

コマンドの出力結果 – show ip ospf

Router1#show ip ospf
 Routing Process "ospf 1" with ID 100.100.100.254
 Start time: 04:17:00.372, Time elapsed: 00:51:26.302
 Supports only single TOS(TOS0) routes
 Supports opaque LSA
 Supports Link-local Signaling (LLS)
 Supports area transit capability
 Supports NSSA (compatible with RFC 3101)
 Supports Database Exchange Summary List Optimization (RFC 5243)
 Event-log enabled, Maximum number of events: 1000, Mode: cyclic
 Router is not originating router-LSAs with maximum metric
 Initial SPF schedule delay 5000 msecs
 Minimum hold time between two consecutive SPFs 10000 msecs
 Maximum wait time between two consecutive SPFs 10000 msecs
 Incremental-SPF disabled
 Minimum LSA interval 5 secs
 Minimum LSA arrival 1000 msecs
 LSA group pacing timer 240 secs
 Interface flood pacing timer 33 msecs
 Retransmission pacing timer 66 msecs
 EXCHANGE/LOADING adjacency limit: initial 300, process maximum 300
 Number of external LSA 0. Checksum Sum 0x000000
 Number of opaque AS LSA 0. Checksum Sum 0x000000
 Number of DCbitless external and opaque AS LSA 0
 Number of DoNotAge external and opaque AS LSA 0
 Number of areas in this router is 1. 1 normal 0 stub 0 nssa
 Number of areas transit capable is 0
 External flood list length 0
 IETF NSF helper support enabled
 Cisco NSF helper support enabled
 Reference bandwidth unit is 100 mbps
    Area BACKBONE(0)
        Number of interfaces in this area is 2
	Area has no authentication
	SPF algorithm last executed 00:30:19.869 ago
	SPF algorithm executed 4 times
	Area ranges are
	Number of LSA 3. Checksum Sum 0x01258D
	Number of opaque link LSA 0. Checksum Sum 0x000000
	Number of DCbitless LSA 0
	Number of indication LSA 0
	Number of DoNotAge LSA 0
	Flood list length 0
Router2#show ip ospf
 Routing Process "ospf 1" with ID 100.100.100.253
 Start time: 04:16:25.436, Time elapsed: 00:51:25.094
 Supports only single TOS(TOS0) routes
 Supports opaque LSA
 Supports Link-local Signaling (LLS)
 Supports area transit capability
 Supports NSSA (compatible with RFC 3101)
 Supports Database Exchange Summary List Optimization (RFC 5243)
 Event-log enabled, Maximum number of events: 1000, Mode: cyclic
 Router is not originating router-LSAs with maximum metric
 Initial SPF schedule delay 5000 msecs
 Minimum hold time between two consecutive SPFs 10000 msecs
 Maximum wait time between two consecutive SPFs 10000 msecs
 Incremental-SPF disabled
 Minimum LSA interval 5 secs
 Minimum LSA arrival 1000 msecs
 LSA group pacing timer 240 secs
 Interface flood pacing timer 33 msecs
 Retransmission pacing timer 66 msecs
 EXCHANGE/LOADING adjacency limit: initial 300, process maximum 300
 Number of external LSA 0. Checksum Sum 0x000000
 Number of opaque AS LSA 0. Checksum Sum 0x000000
 Number of DCbitless external and opaque AS LSA 0
 Number of DoNotAge external and opaque AS LSA 0
 Number of areas in this router is 1. 1 normal 0 stub 0 nssa
 Number of areas transit capable is 0
 External flood list length 0
 IETF NSF helper support enabled
 Cisco NSF helper support enabled
 Reference bandwidth unit is 100 mbps
    Area BACKBONE(0)
        Number of interfaces in this area is 2
	Area has no authentication
	SPF algorithm last executed 00:30:17.619 ago
	SPF algorithm executed 4 times
	Area ranges are
	Number of LSA 3. Checksum Sum 0x01258D
	Number of opaque link LSA 0. Checksum Sum 0x000000
	Number of DCbitless LSA 0
	Number of indication LSA 0
	Number of DoNotAge LSA 0
	Flood list length 0

主に以下のステータスが確認できます。

  • プロセスID
  • ルーターID
  • OSPFの起動時刻 / 起動時間

OSPFネイバー確立状況の確認 – show ip ospf neighbor

OSPFのネイバー確立状況を確認するには下記のコマンドを実行します。

show ip ospf neighbor

コマンドの出力結果 – show ip ospf neighbor

Router1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
100.100.100.253   1   FULL/BDR        00:00:36    172.16.1.2      GigabitEthernet0/0
Router2#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
100.100.100.254   1   FULL/DR         00:00:33    172.16.1.1      GigabitEthernet0/0

主に以下のステータスが確認できます。

  • ネイバーID
  • ネイバーの確立状況(2WAY/EXSTART/EXCHANGE/FULL)
  • ネイバールーターの役割(DR /BDR/DROTHER)
  • ネイバーダウンが検知されるまでの残り時間

OSPFインターフェースの状況確認 – show ip ospf interface

OSPFを有効にしたインターフェースのステータスを確認するには下記のコマンドを実行します。

show ip ospf interface

コマンドの出力結果 – show ip ospf interface

Router1#show ip ospf interface
GigabitEthernet0/1 is up, line protocol is up
  Internet Address 192.168.1.254/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 100.100.100.254, 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) 100.100.100.254, Interface address 192.168.1.254
  No backup designated router on this network
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:03
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/2/2, flood queue length 0
  Next 0x0(0)/0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)
GigabitEthernet0/0 is up, line protocol is up
  Internet Address 172.16.1.1/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 100.100.100.254, 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) 100.100.100.254, Interface address 172.16.1.1
  Backup Designated router (ID) 100.100.100.253, Interface address 172.16.1.2
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:06
  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 2
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 100.100.100.253  (Backup Designated Router)
  Suppress hello for 0 neighbor(s)
Router2#show ip ospf interface
GigabitEthernet0/1 is up, line protocol is up
  Internet Address 192.168.2.254/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 100.100.100.253, 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) 100.100.100.253, Interface address 192.168.2.254
  No backup designated router on this network
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:06
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/2/2, flood queue length 0
  Next 0x0(0)/0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)
GigabitEthernet0/0 is up, line protocol is up
  Internet Address 172.16.1.2/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 100.100.100.253, 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) 100.100.100.254, Interface address 172.16.1.1
  Backup Designated router (ID) 100.100.100.253, Interface address 172.16.1.2
  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 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 100.100.100.254  (Designated Router)
  Suppress hello for 0 neighbor(s)

主に以下のステータスが確認できます。

  • プロセスID
  • ルーターID
  • ネットワークタイプ
  • DR/BDRの情報

OSPFデータベースの状況確認 – show ip ospf database

OSPFの設定を確認するには下記のコマンドを実行します。

show ip ospf database

コマンドの出力結果 – show ip ospf database

Router1#show ip ospf database

            OSPF Router with ID (100.100.100.254) (Process ID 1)

		Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
100.100.100.253 100.100.100.253 1950        0x80000005 0x002AB3 2
100.100.100.254 100.100.100.254 1949        0x80000005 0x00F6E6 2

		Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
172.16.1.1      100.100.100.254 1963        0x80000001 0x0003F4
Router2#show ip ospf database

            OSPF Router with ID (100.100.100.253) (Process ID 1)

		Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
100.100.100.253 100.100.100.253 1947        0x80000005 0x002AB3 2
100.100.100.254 100.100.100.254 1948        0x80000005 0x00F6E6 2

		Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
172.16.1.1      100.100.100.254 1962        0x80000001 0x0003F4

LSAタイプ毎のリンクステートデータベース情報が確認できます。

ルーティングテーブルの確認 – show ip route

ルーティングテーブルの内容を確認するには下記のコマンドを実行します。

show ip route

コマンドの出力結果 – show ip route

Router1#show ip route
Codes: L - local, 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, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C        172.16.1.0/24 is directly connected, GigabitEthernet0/0
L        172.16.1.1/32 is directly connected, GigabitEthernet0/0
      192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.1.0/24 is directly connected, GigabitEthernet0/1
L        192.168.1.254/32 is directly connected, GigabitEthernet0/1
O     192.168.2.0/24 [110/2] via 172.16.1.2, 00:32:45, GigabitEthernet0/0
Router2#show ip route
Codes: L - local, 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, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C        172.16.1.0/24 is directly connected, GigabitEthernet0/0
L        172.16.1.2/32 is directly connected, GigabitEthernet0/0
O     192.168.1.0/24 [110/2] via 172.16.1.1, 00:32:44, GigabitEthernet0/0
      192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.2.0/24 is directly connected, GigabitEthernet0/1
L        192.168.2.254/32 is directly connected, GigabitEthernet0/1

ルーティングテーブルの内容が確認できます。OSPFで相手側のLANセグメントへの経路情報を学習していることがわかります。

ルーティングテーブルの確認(OSPFで学習) – show ip route ospf

OSPFで学習したルーティングテーブルの内容を確認するには下記のコマンドを実行します。

show ip route ospf

コマンドの出力結果 – show ip route ospf

Router1#show ip route ospf
Codes: L - local, 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, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

O     192.168.2.0/24 [110/2] via 172.16.1.2, 00:32:54, GigabitEthernet0/0
Router2#show ip route ospf
Codes: L - local, 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, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

O     192.168.1.0/24 [110/2] via 172.16.1.1, 00:32:53, GigabitEthernet0/0

OSPFで学習したルーティングテーブルの内容が確認できます。OSPFで相手側のLANセグメントへの経路情報を学習していることがわかります。

以上で、「OSPFの基本設定 – Cisco機器での設定方法」の説明は完了です！

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