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OSPF スタブエリアの練習
本エントリについて
Dynagen、Dynamips を使って、OSPF を練習します。
Dynagen、Dynamips の利用環境はすでに整っているものとします。
参考
基本設定
https://zenn.dev/mnod/articles/ba267c7eecabaf の続編です。
スタブエリア
下記図で area 1 をスタブエリアとします。
area0 area0 area1
eigrp1 [r1] area0 [r2] area1 [r4]
事前設定
r2、r4 でEIGRP を停止して、OSPF area 1 を追加します。
r2(config)#no router eigrp 1
r2(config)#router ospf 1
r2(config-router)#network 172.16.2.0 0.0.0.255 area 1
r4(config)#no router eigrp 1
r4(config)#router ospf 1
r4(config-router)#network 10.2.3.0 0.0.0.255 area 1
r4(config-router)#network 172.16.2.0 0.0.0.255 area 1
r4 でトポロジーテーブルとルーティングテーブルを確認します。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 32 0x80000009 0x0039FD 2
192.168.3.1 192.168.3.1 32 0x80000005 0x00F969 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 59 0x80000003 0x003DEA
10.2.1.0 172.16.2.253 59 0x80000003 0x00AFB7
172.16.0.0 172.16.2.253 59 0x80000003 0x00ED93
r4#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O IA 172.16.0.0 [110/128] via 172.16.2.253, 00:00:33, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O IA 10.2.0.0 [110/138] via 172.16.2.253, 00:00:33, Serial1/1
O IA 10.2.1.0 [110/74] via 172.16.2.253, 00:00:33, Serial1/1
r2 でトポロジーテーブルとルーティングテーブルを確認します。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 644 0x8000000B 0x007056 3
172.16.2.253 172.16.2.253 1382 0x8000000B 0x005968 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 81 0x80000001 0x002007
172.16.2.0 172.16.2.253 1378 0x80000001 0x00DBA5
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 85 0x80000009 0x0039FD 2
192.168.3.1 192.168.3.1 86 0x80000005 0x00F969 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 112 0x80000003 0x003DEA
10.2.1.0 172.16.2.253 114 0x80000003 0x00AFB7
172.16.0.0 172.16.2.253 114 0x80000003 0x00ED93
r2#show ip route ospf
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:02:00, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:01:29, Serial1/0
r1 でトポロジーテーブルとルーティングテーブルを確認します。
r1#show ip ospf database
OSPF Router with ID (172.16.1.254) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 681 0x8000000B 0x007056 3
172.16.2.253 172.16.2.253 1422 0x8000000B 0x005968 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 120 0x80000001 0x002007
172.16.2.0 172.16.2.253 1417 0x80000001 0x00DBA5
r1#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O IA 172.16.2.0 [110/128] via 172.16.0.254, 00:11:23, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.1.0 [110/74] via 172.16.0.254, 00:11:23, Serial1/0
O IA 10.2.3.0 [110/138] via 172.16.0.254, 00:02:06, Serial1/0
r1 で EIGRP 経路を再配布
r1 で EIGRP を動作させます。
EIGRP の経路をOSPFへ再配布します。
r1(config)#router eigrp 1
r1(config-router)#network 172.16.1.0 0.0.0.255
r1(config-router)#router ospf 1
r1(config-router)#redistribute eigrp 1 metric-type 1 subnets
r1 の状態を確認します。
r1#show ip eigrp topology
IP-EIGRP Topology Table for AS(1)/ID(172.16.1.254)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 172.16.1.0/24, 1 successors, FD is 2169856
via Connected, Serial1/1
r1#show ip ospf database
OSPF Router with ID (172.16.1.254) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 21 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 505 0x80000001 0x002007
172.16.2.0 172.16.2.253 1802 0x80000001 0x00DBA5
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 20 0x80000001 0x004066 0
r1#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O IA 172.16.2.0 [110/128] via 172.16.0.254, 00:17:47, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.1.0 [110/74] via 172.16.0.254, 00:17:47, Serial1/0
O IA 10.2.3.0 [110/138] via 172.16.0.254, 00:08:30, Serial1/0
r2 の状態を確認します。
Summary ASB Link States は LSA タイプ4(ASBR集約LSA) を表します。
ASBRのあるエリアのABRで生成し、ABRが知っているASBRのルータID、コスト値を含みます。スタブエリア、NSSAを除くAS全体にフラッディングします。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 81 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 59 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 563 0x80000001 0x002007
172.16.2.0 172.16.2.253 1861 0x80000001 0x00DBA5
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 568 0x80000009 0x0039FD 2
192.168.3.1 192.168.3.1 569 0x80000005 0x00F969 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 595 0x80000003 0x003DEA
10.2.1.0 172.16.2.253 596 0x80000003 0x00AFB7
172.16.0.0 172.16.2.253 596 0x80000003 0x00ED93
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
172.16.1.254 172.16.2.253 77 0x80000001 0x00E29F
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 82 0x80000001 0x004066 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:01:21, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:10:01, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:09:29, Serial1/0
r4 の状態を確認します。
タイプ4、タイプ5のLSAが見られます。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 616 0x80000009 0x0039FD 2
192.168.3.1 192.168.3.1 615 0x80000005 0x00F969 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 643 0x80000003 0x003DEA
10.2.1.0 172.16.2.253 643 0x80000003 0x00AFB7
172.16.0.0 172.16.2.253 643 0x80000003 0x00ED93
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
172.16.1.254 172.16.2.253 124 0x80000001 0x00E29F
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 129 0x80000001 0x004066 0
r4#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O IA 172.16.0.0 [110/128] via 172.16.2.253, 00:10:11, Serial1/1
O E1 172.16.1.0 [110/148] via 172.16.2.253, 00:02:03, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O IA 10.2.0.0 [110/138] via 172.16.2.253, 00:10:11, Serial1/1
O IA 10.2.1.0 [110/74] via 172.16.2.253, 00:10:11, Serial1/1
スタブエリア設定
ABRである r2 でスタブエリアの設定をします。
r2(config)#router ospf 1
r2(config-router)#area 1 stub
スタブエリアのルータであるr4でもスタブエリアの設定をします。
r4(config)#router ospf 1
r4(config-router)#area 1 stub
r4 で状態を確認します。
タイプ4、タイプ5 のLSAが見られなくなりました。
また、デフォルトルートのタイプ3 LSAが見られるようになりました。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 50 0x8000000B 0x004DEB 2
192.168.3.1 192.168.3.1 44 0x80000007 0x00144F 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 65 0x80000001 0x001D64
10.2.0.0 172.16.2.253 65 0x80000004 0x0059CF
10.2.1.0 172.16.2.253 65 0x80000004 0x00CB9C
172.16.0.0 172.16.2.253 65 0x80000004 0x000A78
r4#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O IA 172.16.0.0 [110/128] via 172.16.2.253, 00:00:41, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O IA 10.2.0.0 [110/138] via 172.16.2.253, 00:00:41, Serial1/1
O IA 10.2.1.0 [110/74] via 172.16.2.253, 00:00:41, Serial1/1
O*IA 0.0.0.0/0 [110/65] via 172.16.2.253, 00:00:41, Serial1/1
r2 で状態を確認します。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 284 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 262 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 78 0x80000001 0x002007
172.16.2.0 172.16.2.253 16 0x80000002 0x00D9A6
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 83 0x8000000B 0x004DEB 2
192.168.3.1 192.168.3.1 79 0x80000007 0x00144F 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 99 0x80000001 0x001D64
10.2.0.0 172.16.2.253 100 0x80000004 0x0059CF
10.2.1.0 172.16.2.253 100 0x80000004 0x00CB9C
172.16.0.0 172.16.2.253 100 0x80000004 0x000A78
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 285 0x80000001 0x004066 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:01:44, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:01:44, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:01:23, Serial1/0
トータリースタブエリア
エリア1 をトータリースタブエリアに設定します。
ABR である r2 の設定を変更します。
スタブエリア内のルータである r4 は設定を変更する必要はありません。
r2(config)#router ospf 1
r2(config-router)#area 1 stub no-summary
r2 で状態を確認します。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 481 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 458 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 275 0x80000001 0x002007
172.16.2.0 172.16.2.253 213 0x80000002 0x00D9A6
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 279 0x8000000B 0x004DEB 2
192.168.3.1 192.168.3.1 276 0x80000007 0x00144F 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 23 0x80000002 0x001B65
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 482 0x80000001 0x004066 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:00:31, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:00:31, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:00:31, Serial1/0
r4 でトポロジーテーブルとルーティングテーブルを確認します。
タイプ3 LSAが、デフォルトルートのもののみになりました。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 324 0x8000000B 0x004DEB 2
192.168.3.1 192.168.3.1 319 0x80000007 0x00144F 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 67 0x80000002 0x001B65
r4#show ip route ospf
O*IA 0.0.0.0/0 [110/65] via 172.16.2.253, 00:01:08, Serial1/1
Not-So-Stubby Area (NSSA)
下記図で area 1 を NSSA とします。
area0 area0 area1
eigrp1 [r1] area0 [r2] area1 [r4] eigrp1
事前設定
前項のシナリオに続いて、r4 で eigrp を動作させます。
r4(config)#router eigrp 1
r4(config-router)#network 172.16.3.0 0.0.0.255
r4(config-router)#router ospf 1
r4(config-router)#redistribute eigrp 1 metric-type 1 subnets
状態を確認します。
r4#show ip eigrp topolo
IP-EIGRP Topology Table for AS(1)/ID(192.168.3.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 172.16.3.0/24, 1 successors, FD is 2169856
via Connected, Serial1/0
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 915 0x8000000B 0x004DEB 2
192.168.3.1 192.168.3.1 910 0x80000007 0x00144F 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 658 0x80000002 0x001B65
r4#show ip route ospf
O*IA 0.0.0.0/0 [110/65] via 172.16.2.253, 00:11:22, Serial1/1
r2 で状態を確認します。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 1217 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1195 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 1012 0x80000001 0x002007
172.16.2.0 172.16.2.253 949 0x80000002 0x00D9A6
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 1016 0x8000000B 0x004DEB 2
192.168.3.1 192.168.3.1 1013 0x80000007 0x00144F 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 760 0x80000002 0x001B65
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1221 0x80000001 0x004066 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:12:52, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:12:52, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:12:52, Serial1/0
r1 で状態を確認します。
r1#show ip ospf database
OSPF Router with ID (172.16.1.254) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 1266 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1246 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 1062 0x80000001 0x002007
172.16.2.0 172.16.2.253 1000 0x80000002 0x00D9A6
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1265 0x80000001 0x004066 0
r1#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O IA 172.16.2.0 [110/128] via 172.16.0.254, 00:38:35, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.1.0 [110/74] via 172.16.0.254, 00:38:35, Serial1/0
O IA 10.2.3.0 [110/138] via 172.16.0.254, 00:17:50, Serial1/0
r2、r4で、スタブエリアの設定を解除します。
r2(config)#router ospf 1
r2(config-router)#no area 1 stub
r4(config)#router ospf 1
r4(config-router)#no area 1 stub
状態を確認します。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 60 0x8000000D 0x003102 2
192.168.3.1 192.168.3.1 56 0x80000009 0x00F765 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 82 0x80000001 0x0041E8
10.2.1.0 172.16.2.253 82 0x80000001 0x00B3B5
172.16.0.0 172.16.2.253 82 0x80000001 0x00F191
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
172.16.1.254 172.16.2.253 82 0x80000001 0x00E29F
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1414 0x80000001 0x004066 0
172.16.3.0 192.168.3.1 62 0x80000001 0x00965D 0
r4#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O IA 172.16.0.0 [110/128] via 172.16.2.253, 00:00:55, Serial1/1
O E1 172.16.1.0 [110/148] via 172.16.2.253, 00:00:55, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O IA 10.2.0.0 [110/138] via 172.16.2.253, 00:00:55, Serial1/1
O IA 10.2.1.0 [110/74] via 172.16.2.253, 00:00:55, Serial1/1
r2 で状態を確認します。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 1444 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1422 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 84 0x80000001 0x002007
172.16.2.0 172.16.2.253 1176 0x80000002 0x00D9A6
Summary ASB Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.3.1 172.16.2.253 84 0x80000001 0x008C45
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 89 0x8000000D 0x003102 2
192.168.3.1 192.168.3.1 88 0x80000009 0x00F765 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 114 0x80000001 0x0041E8
10.2.1.0 172.16.2.253 114 0x80000001 0x00B3B5
172.16.0.0 172.16.2.253 114 0x80000001 0x00F191
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
172.16.1.254 172.16.2.253 114 0x80000001 0x00E29F
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1446 0x80000001 0x004066 0
172.16.3.0 192.168.3.1 92 0x80000001 0x00965D 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:02:00, Serial1/1
O E1 172.16.3.0 [110/84] via 172.16.2.254, 00:01:32, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:02:00, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:01:32, Serial1/0
r1 で状態を確認します。
r1#show ip ospf database
OSPF Router with ID (172.16.1.254) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 1474 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1453 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 116 0x80000001 0x002007
172.16.2.0 172.16.2.253 1208 0x80000002 0x00D9A6
Summary ASB Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.3.1 172.16.2.253 116 0x80000001 0x008C45
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1473 0x80000001 0x004066 0
172.16.3.0 192.168.3.1 124 0x80000001 0x00965D 0
r1#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O IA 172.16.2.0 [110/128] via 172.16.0.254, 00:41:59, Serial1/0
O E1 172.16.3.0 [110/148] via 172.16.0.254, 00:01:55, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.1.0 [110/74] via 172.16.0.254, 00:41:59, Serial1/0
O IA 10.2.3.0 [110/138] via 172.16.0.254, 00:02:00, Serial1/0
NSSA 設定
ABR である r2 で NSSA の設定をします。
r2(config)#router ospf 1
r2(config-router)#area 1 nssa default-information-originate
NSSA のルータである r4 で NSSA の設定をします。
r4(config)#router ospf 1
r4(config-router)#area 1 nssa
r4 でトポロジーテーブルとルーティングテーブルを確認します。
Type-7 AS External Link States は LSA タイプ7(NSSA外部LSA) を表します。
NSSA の ASBR が生成し、 再配布した経路情報、コスト、ネクストホップを含みます。NSSA内にフラッディングします。
タイプ7 LSAは NSSA 内のみに存在し、ABR はタイプ5 LSAに変換して他のエリアへフラッディングします。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 39 0x8000000F 0x00D258 2
192.168.3.1 192.168.3.1 214 0x80000009 0x00F765 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 55 0x80000002 0x00E43E
10.2.1.0 172.16.2.253 55 0x80000002 0x00570B
172.16.0.0 172.16.2.253 55 0x80000002 0x0095E6
Type-7 AS External Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Tag
0.0.0.0 172.16.2.253 55 0x80000001 0x00787C 0
172.16.3.0 192.168.3.1 37 0x80000001 0x003AF1 0
r4#show ip route ospf
172.16.0.0/24 is subnetted, 3 subnets
O IA 172.16.0.0 [110/128] via 172.16.2.253, 00:00:43, Serial1/1
10.0.0.0/24 is subnetted, 3 subnets
O IA 10.2.0.0 [110/138] via 172.16.2.253, 00:00:43, Serial1/1
O IA 10.2.1.0 [110/74] via 172.16.2.253, 00:00:43, Serial1/1
O*N2 0.0.0.0/0 [110/1] via 172.16.2.253, 00:00:43, Serial1/1
r2 で状態を確認します。
172.16.3.0 のタイプ5 LSAは、NSSA 内のタイプ7 LSAが、ABR(r2)でタイプ5に変換されたものです。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 1609 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1587 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 69 0x80000001 0x002007
172.16.2.0 172.16.2.253 1341 0x80000002 0x00D9A6
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 74 0x8000000F 0x00D258 2
192.168.3.1 192.168.3.1 251 0x80000009 0x00F765 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.2.0.0 172.16.2.253 91 0x80000002 0x00E43E
10.2.1.0 172.16.2.253 92 0x80000002 0x00570B
172.16.0.0 172.16.2.253 92 0x80000002 0x0095E6
Type-7 AS External Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Tag
0.0.0.0 172.16.2.253 92 0x80000001 0x00787C 0
172.16.3.0 192.168.3.1 76 0x80000001 0x003AF1 0
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1610 0x80000001 0x004066 0
172.16.3.0 172.16.2.253 69 0x80000001 0x006185 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:01:36, Serial1/1
O N1 172.16.3.0 [110/84] via 172.16.2.254, 00:01:15, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:01:36, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:01:15, Serial1/0
r1 で状態を確認します。
r1#show ip ospf database
OSPF Router with ID (172.16.1.254) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 1638 0x8000000C 0x00744F 3
172.16.2.253 172.16.2.253 1618 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 100 0x80000001 0x002007
172.16.2.0 172.16.2.253 1372 0x80000002 0x00D9A6
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 1637 0x80000001 0x004066 0
172.16.3.0 172.16.2.253 99 0x80000001 0x006185 0
r1#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O IA 172.16.2.0 [110/128] via 172.16.0.254, 00:44:43, Serial1/0
O E1 172.16.3.0 [110/148] via 172.16.0.254, 00:01:39, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.1.0 [110/74] via 172.16.0.254, 00:44:43, Serial1/0
O IA 10.2.3.0 [110/138] via 172.16.0.254, 00:01:44, Serial1/0
トータリーNSSA
ABR である r2 でトータリーNSSA の設定をします。
NSSA のルータである r4 では特に追加設定は必要ありません。
r2(config)#router ospf 1
r2(config-router)#no area 1 nssa default-information-originate
r2(config-router)#area 1 nssa no-summary
r4 で状態を確認します。
タイプ3 LSAが、デフォルトルートのものだけになりました。
r4#show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 359 0x8000000F 0x00D258 2
192.168.3.1 192.168.3.1 535 0x80000009 0x00F765 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 41 0x80000001 0x00A4D4
Type-7 AS External Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Tag
172.16.3.0 192.168.3.1 358 0x80000001 0x003AF1 0
r4#show ip route ospf
O*IA 0.0.0.0/0 [110/65] via 172.16.2.253, 00:00:48, Serial1/1
r2 で状態を確認します。
r2#show ip ospf database
OSPF Router with ID (172.16.2.253) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 47 0x8000000D 0x007250 3
172.16.2.253 172.16.2.253 1977 0x8000000C 0x005769 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 459 0x80000001 0x002007
172.16.2.0 172.16.2.253 1731 0x80000002 0x00D9A6
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.253 172.16.2.253 464 0x8000000F 0x00D258 2
192.168.3.1 192.168.3.1 642 0x80000009 0x00F765 3
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 172.16.2.253 146 0x80000001 0x00A4D4
Type-7 AS External Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Tag
172.16.3.0 192.168.3.1 467 0x80000001 0x003AF1 0
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 49 0x80000002 0x003E67 0
172.16.3.0 172.16.2.253 460 0x80000001 0x006185 0
r2#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O E1 172.16.1.0 [110/84] via 172.16.0.253, 00:02:33, Serial1/1
O N1 172.16.3.0 [110/84] via 172.16.2.254, 00:02:33, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.0.0 [110/74] via 172.16.0.253, 00:02:33, Serial1/1
O 10.2.3.0 [110/74] via 172.16.2.254, 00:02:33, Serial1/0
r1 で状態を確認します。
r1#show ip ospf database
OSPF Router with ID (172.16.1.254) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
172.16.1.254 172.16.1.254 71 0x8000000D 0x007250 3
172.16.2.253 172.16.2.253 2 0x8000000D 0x00556A 3
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.2.3.0 172.16.2.253 486 0x80000001 0x002007
172.16.2.0 172.16.2.253 1758 0x80000002 0x00D9A6
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0 172.16.1.254 71 0x80000002 0x003E67 0
172.16.3.0 172.16.2.253 485 0x80000001 0x006185 0
r1#show ip route ospf
172.16.0.0/24 is subnetted, 4 subnets
O IA 172.16.2.0 [110/128] via 172.16.0.254, 00:51:07, Serial1/0
O E1 172.16.3.0 [110/148] via 172.16.0.254, 00:08:03, Serial1/0
10.0.0.0/24 is subnetted, 3 subnets
O 10.2.1.0 [110/74] via 172.16.0.254, 00:51:07, Serial1/0
O IA 10.2.3.0 [110/138] via 172.16.0.254, 00:08:08, Serial1/0
まとめ
Dynagen、Dynamips を使って、OSPF を練習しました。
スタブエリア、NSSA の設定によって、エリア内に配布されるLSAが少なくなり、ルーティングテーブルを小さくすることができるようになりました。
ABRは複数のエリアのLSAを処理する必要があります。ASBRのルータは複数のルーティングプロトコルを動かす必要があります。
Discussion