疑難排解開放最短路徑優先路由資料庫相關問題
簡介
本文說明當資料庫中的路由不在路由資訊庫 (RIB) 或路由表中時，如何修復 OSPF 問題。
必要條件
需求
本文檔的讀者必須瞭解以下主題：
-
開放最短路徑優先(OSPF)協定的基本知識
-
Cisco IOS®中的OSPF配置基礎知識
採用元件
本文中的資訊係根據以下軟體和硬體版本：
-
Cisco IOS軟體版本12及更新版本
-
所有思科路由器平台都支援此功能
本文中的資訊是根據特定實驗室環境內的裝置所建立。文中使用到的所有裝置皆從已清除（預設）的組態來啟動。如果您的網路運作中，請確保您瞭解任何指令可能造成的影響。
慣例
如需文件慣例的詳細資訊，請參閱思科技術提示慣例。
背景資訊
本文描述開放最短路徑優先(OSPF)的一個常見問題，即資料庫中的路由不會出現在路由資訊庫(RIB)或路由表中。在大多數情況下，OSPF會發現資料庫中的差異，因此不會在路由表中安裝路由。通常，當發生此問題時，您會在資料庫的鏈路狀態通告(LSA)上看到Adv Router is not-reachable消息（這意味著通告LSA的路由器無法通過OSPF到達）。以下是範例：
Router#show ip ospf database router 172.16.32.2
Adv Router is not-reachableLS age: 418 Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 172.16.32.2 Advertising Router: 172.16.32.2 LS Seq Number: 80000002 Checksum: 0xFA63 Length: 60 Number of Links: 3
造成此問題的原因有多種，其中大多數的原因都是配置錯誤或拓撲斷開。更正配置後，OSPF資料庫差異消失，路由顯示在路由表中。本文檔解釋了可能導致資料庫中存在差異的一些更常見原因。
本文檔中用於驗證OSPF行為的一些命令包括show ip ospf interface、show ip ospf database router、show ip ospf neighbor和show ip ospf database external。如果您的Cisco裝置輸出了這些命令中的任意一個，則可以使用Cisco CLI Analyzer顯示潛在的問題和解決方法。
原因1：網路型別不匹配
下一個網路圖用作示例：
| R4-4K |
R1-7010 |
interface Loopback0 ip address 172.16.33.1 255.255.255.255 ! interface Serial2 ip address 172.16.32.1 255.255.255.0 ip ospf network broadcast ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
interface Loopback0 ip address 172.16.30.1 255.255.255.255 ! interface Serial1/0 ip address 172.16.32.2 255.255.255.0 clockrate 64000 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
R4-4K(4)#show ip ospf interface serial 2
Serial2 is up, line protocol is up
Internet Address 172.16.32.1/24, Area 0
Process ID 20, Router ID 172.16.33.1, Network Type BROADCAST, Cost: 64
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.33.1, Interface address 172.16.32.1
Backup Designated router (ID) 172.16.32.2, Interface address 172.16.32.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:08
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 172.16.32.2 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
R1-7010(5)#show ip ospf interface serial 1/0
Serial1/0 is up, line protocol is up
Internet Address 172.16.32.2/24, Area 0
Process ID 20, Router ID 172.16.32.2, Network Type POINT_TO_POINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 172.16.33.1
Suppress hello for 0 neighbor(s)
如前面的輸出所示，路由器R4-4K配置為廣播，路由器R1-7010配置為點對點。這種網路型別不相符會導致廣告路由器無法連線。
R4-4K(4)#show ip ospf database router 172.16.32.2
Adv Router is not-reachable
LS age: 418
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.16.32.2
Advertising Router: 172.16.32.2
LS Seq Number: 80000002
Checksum: 0xFA63
Length: 60
Number of Links: 3
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 172.16.33.1
(Link Data) Router Interface address: 172.16.32.2
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 172.16.32.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 64
R1-7010(5)#show ip ospf database router 172.16.33.1
Adv Router is not-reachable
LS age: 357
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.16.33.1
Advertising Router: 172.16.33.1
LS Seq Number: 8000000A
Checksum: 0xD4AA
Length: 48
Number of Links: 2
Link connected to: a Transit Network
(Link ID) Designated Router address: 172.16.32.1
(Link Data) Router Interface address: 172.16.32.1
Number of TOS metrics: 0
TOS 0 Metrics: 64
您可以看到，對於子網172.16.32.0/24，路由器R1-7010生成一條點對點鏈路，路由器R4-4K生成一條傳輸鏈路。這會導致鏈路狀態資料庫中存在不一致，這意味著路由表中未安裝任何路由。
R1-7010(5)#show ip route 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks C 172.16.32.0/24 is directly connected, Serial1/0 C 172.16.30.1/32 is directly connected, Loopback0
解決方案
要解決此問題，請將兩台路由器配置為同一網路型別。您可以將路由器R1-7010的網路型別更改為廣播，或者將路由器R4-4K串列介面更改為點對點。
在本示例中，我們刪除了R4-4K上的network-type broadcast語句，因為兩端都是點對點高級資料鏈路控制(HDLC)封裝的介面。
R4-4K(4)#configure terminal R4-4K(4)(config)#interface serial 2 R4-4K(4)(config-if)#no ip ospf network broadcast R4-4K(4)(config-if)#end R4-4K(4)#show ip ospf interface serial 2 Serial2 is up, line protocol is up Internet Address 172.16.32.1/24, Area 0 Process ID 20, Router ID 172.16.33.1, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:04 Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 172.16.32.2 Suppress hello for 0 neighbor(s)
原因2：雙串列鏈路設定中的地址分配錯誤
請考慮以下網路圖作為範例：
| R4-4K |
R1-7010 |
interface loopback 0 ip address 172.16.35.1 255.255.255.255 ! interface Serial2 ip address 172.16.29.1 255.255.255.0 ! interface Serial3 ip address 172.16.32.1 255.255.255.0 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
interface loopback 0 ip address 172.16.30.1 255.255.255.255 ! interface Serial1/0 ip address 172.16.32.2 255.255.255.0 clockrate 64000 ! interface Serial1/1 ip address 172.16.29.2 255.255.255.0 clockrate 38400 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
您可以看到，IP地址在以前的配置中發生翻轉，導致OSPF資料庫中存在差異。但是，這些路由器仍然在Cisco IOS版本12.1之前形成鄰居，因為在點對點鏈路上，OSPF路由器不會驗證相鄰路由器是否位於同一子網中。
R4-4K(4)#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 172.16.32.2 1 FULL/ - 00:00:37 172.16.32.2 Serial2 172.16.32.2 1 FULL/ - 00:00:31 172.16.29.2 Serial3
從上面的輸出中，您可以看到Serial2用於形成IP地址為172.16.32.2的鄰居，該鄰居不在同一個子網中。雖然形成了鄰居，但路由表中未安裝任何路由：
R1-7010(5)#show ip route 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks C 172.16.32.0/24 is directly connected, Serial1/0 C 172.16.29.0/24 is directly connected, Serial1/1 C 172.16.30.1/32 is directly connected, Loopback0
解決方案
要解決此問題，請正確分配IP地址或交換串列電纜。我們已更正以下IP地址：
| R4-4K |
R1-7010 |
interface loopback 0 ip address 172.16.35.1 255.255.255.255 ! interface Serial2 ip address 172.16.32.1 255.255.255.0 ! interface Serial3 ip address 172.16.29.1 255.255.255.0 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
interface loopback 0 ip address 172.16.30.1 255.255.255.255 ! interface Serial1/0 ip address 172.16.32.2 255.255.255.0 clockrate 64000 ! interface Serial1/1 ip address 172.16.29.2 255.255.255.0 clockrate 38400 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
R4-4K(4)#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 172.16.32.2 1 FULL/ - 00:00:36 172.16.32.2 Serial2 172.16.32.2 1 FULL/ - 00:00:39 172.16.29.2 Serial3
現在它顯示了Serial 2介面的正確鄰居地址。路由表也包含這些路由：
R1-7010(5)#show ip route
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 172.16.32.0/24 is directly connected, Serial1/0
O 172.16.35.1/32 [110/65] via 172.16.32.1, 00:03:12, Serial1/0
[110/65] via 172.16.29.1, 00:03:12, Serial1/1
C 172.16.29.0/24 is directly connected, Serial1/1
C 172.16.30.1/32 is directly connected, Loopback0
原因3：錯誤的主網或子網中包含點對點鏈路的一端
請考慮以下網路圖作為範例：
這種情況產生的行為與雙串列鏈路設定中的錯誤地址分配完全相同。要解決此問題，請在兩台路由器上分配同一子網中的IP地址。
原因4：一側未編號，另一側已編號
請考慮下一個網路圖作為範例：
| R4-4K | R1-7010 |
|---|---|
interface Loopback0 ip address 172.16.35.1 255.255.255.255 ! interface Serial2 ip unnumbered Loopback0 router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
interface Loopback0 ip address 172.16.30.1 255.255.255.255 ! interface Serial1/0 ip address 172.16.32.2 255.255.255.0 clockrate 64000 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
R4-4K(4)#show interface serial 2 Serial2 is up, line protocol is up Hardware is cxBus Serial Interface is unnumbered. Using address of Loopback0 (172.16.35.1) R1-7010(5)#show interface serial 1/0 Serial1/0 is up, line protocol is up Hardware is cxBus Serial Internet address is 172.16.32.2/24
先前的輸出顯示，R4-4K Serial 2介面未編號為Loopback0（使用Loopback0 172.16.35.1的地址），而R1-7010的Serial 1/0介面為編號介面。
R4-4K(4)#show ip ospf interface serial 2
Serial2 is up, line protocol is up
Internet Address 0.0.0.0/24, Area 0
Process ID 20, Router ID 172.16.35.1, Network Type POINT_TO_POINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 172.16.32.2
Suppress hello for 0 neighbor(s)
R1-7010(5)#show ip ospf interface serial 1/0
Serial1/0 is up, line protocol is up
Internet Address 172.16.32.2/24, Area 0
Process ID 20, Router ID 172.16.32.2, Network Type POINT_TO_POINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 172.16.33.1
Suppress hello for 0 neighbor(s)
正如前面所看到的，這兩種情況中的network-type都是點對點的。問題是一端未編號，而另一端未編號，這樣會在資料庫中產生差異，如下所示。
R4-4K(4)#show ip ospf database router 172.16.30.1
OSPF Router with ID (172.16.35.1) (Process ID 20)
Router Link States (Area 0)
LS age: 202
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.16.30.1
Advertising Router: 172.16.30.1
LS Seq Number: 80000002
Checksum: 0xC899
Length: 60
Number of Links: 3
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 172.16.35.1
(Link Data) Router Interface address: 172.16.32.2
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 172.16.32.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 172.16.30.1
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
R1-7010(5)#show ip ospf database router 172.16.35.1
OSPF Router with ID (172.16.30.1) (Process ID 20)
Router Link States (Area 0)
Adv Router is not-reachable
LS age: 396
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.16.35.1
Advertising Router: 172.16.35.1
LS Seq Number: 80000003
Checksum: 0xBEA1
Length: 48
Number of Links: 2
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 172.16.30.1
(Link Data) Router Interface address: 0.0.0.3
!--- In case of an unnumbered link we use MIB-II IfIndex value which usually starts with 0.
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 172.16.35.1
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
R1-7010(5)#
您可以看到，R1-7010使用包含其介面地址的Link Data欄位為此點對點鏈路生成LSA，而R4-4K使用包含MIB-II IfIndex值的Link Data欄位為同一鏈路生成LSA(RFC 2328)。這會導致鏈路狀態資料庫中存在不一致，這意味著路由表中未安裝任何路由。
R1-7010(5)#show ip route 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks C 172.16.32.0/24 is directly connected, Serial1/0 C 172.16.30.1/32 is directly connected, Loopback0
解決方案
要解決此問題，請將兩台路由器的串列介面配置為已編號或未編號。在本例中，我們對路由器R4-4K的串列2介面進行了編號。
R4-4K(4)#configure terminal
R4-4K(4)(config)#interface serial 2
R4-4K(4)(config-if)#no ip unnumbered loopback 0
R4-4K(4)(config-if)#ip address 172.16.32.1 255.255.255.0
R4-4K(4))#show ip ospf interface serial 2
Serial2 is up, line protocol is up
Internet Address 172.16.32.1/24, Area 0
Process ID 20, Router ID 172.16.33.1, Network Type POINT_TO_POINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 172.16.32.2
Suppress hello for 0 neighbor(s)
R1-7010(5)#show ip route
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
C 172.16.32.0/24 is directly connected, Serial1/0
O 172.16.33.1/32 [110/65] via 172.16.32.1, 00:03:08, Serial1/0
C 172.16.30.1/32 is directly connected, Loopback0
原因5：全網狀幀中繼環境中的PVC斷開
請考慮以下網路圖作為範例：
| R9-2500 |
interface Loopback0 ip address 10.50.50.50 255.255.255.255 ! interface Serial0 ip address 10.10.10.5 255.255.255.0 encapsulation frame-relay ip ospf network broadcast frame-relay map ip 10.10.10.6 102 broadcast frame-relay map ip 10.10.10.7 101 broadcast ! router ospf 10 network 10.10.10.0 0.0.0.255 area 0 network 10.50.50.0 0.0.0.255 area 0 |
| R4-4K |
interface Loopback0 ip address 10.70.70.70 255.255.255.255 ! interface Serial0 ip address 10.10.10.7 255.255.255.0 encapsulation frame-relay ip ospf network broadcast frame-relay map ip 10.10.10.5 101 broadcast frame-relay map ip 10.10.10.6 100 broadcast ! router ospf 10 network 10.10.10.0 0.0.0.255 area 0 network 10.70.70.0 0.0.0.255 area 0 |
| R3-4K |
interface Loopback0 ip address 10.60.60.60 255.255.255.255 ! interface Serial0 no ip address encapsulation frame-relay ! interface Serial0.1 multipoint ip address 10.10.10.6 255.255.255.0 ip ospf network broadcast frame-relay map ip 10.10.10.5 102 broadcast frame-relay map ip 10.10.10.7 100 broadcast ! router ospf 10 network 10.10.10.0 0.0.0.255 area 0 network 10.60.60.0 0.0.0.255 area 0 |
只要幀中繼網雲是全網狀的，幀中繼上的廣播模型就可以正常工作。如果任何永久虛擬電路(PVC)損壞，它可能會在OSPF資料庫中出現問題，從而產生Adv路由器無法訪問消息。
在本示例中，R9-2500和R4-4K之間的PVC斷開，通往指定路由器(DR)的R9-2500鏈路斷開。因此，R9-2500宣告來自R3-4K（不是DR）的所有LSA不可達。您可以看到，R9-2500不會為連線到R3-4K的串列介面生成傳輸鏈路；而是生成末節鏈路，因為對於R9-2500而言，此鏈路上沒有DR。
R9-2500(3)#show ip ospf database router
OSPF Router with ID (10.50.50.50) (Process ID 10)
Router Link States (Area 0)
LS age: 148
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 10.50.50.50
Advertising Router: 10.50.50.50
LS Seq Number: 8000000B
Checksum: 0x55A
Length: 48
Number of Links: 2
Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.10.10.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.50.50.50
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
Adv Router is not-reachable
LS age: 1081
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 10.60.60.60
Advertising Router: 10.60.60.60
LS Seq Number: 80000006
Checksum: 0x4F72
Length: 48
Number of Links: 2
Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.60.60.60
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.10.10.7
(Link Data) Router Interface address: 10.10.10.6
Number of TOS metrics: 0
TOS 0 Metrics: 64
Adv Router is not-reachable
LS age: 306
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 10.70.70.70
Advertising Router: 10.70.70.70
LS Seq Number: 80000007
Checksum: 0xC185
Length: 48
Number of Links: 2
Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.70.70.70
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.10.10.7
(Link Data) Router Interface address: 10.10.10.7
Number of TOS metrics: 0
TOS 0 Metrics: 64
有關此問題的詳細資訊，請參閱幀中繼上的NBMA和廣播模式中的OSPF問題。
原因6：通過外部路由已知的轉發地址
請考慮以下網路圖作為範例：
| R2507 |
interface GigabitEthernet0/0 ip address 10.1.1.1 255.255.255.0 ! interface GigabitEthernet0/1 ip address 10.7.7.1 255.255.255.0 ! router ospf 1 network 10.1.1.1 0.0.0.0 area 0 default-information originate metric 20 ! ip route 0.0.0.0 0.0.0.0 10.7.7.2 |
| R2504 |
interface GigabitEthernet0/0 ip address 10.1.1.2 255.255.255.0 ! interface GigabitEthernet0/1 ip address 10.3.4.2 255.255.255.0 ! router ospf 1 network 10.1.1.0 0.0.0.255 area 0 network 10.0.0.0 0.255.255.255 area 1 area 1 range 10.0.0.0 255.0.0.0 |
| R2515 |
interface GigabitEthernet0/0 ip address 10.3.4.3 255.255.255.0 ! interface GigabitEthernet0/2 ip address 10.44.66.3 255.255.255.0 ! interface GigabitEthernet0/3 ip address 10.22.88.3 255.255.255.0 ! router ospf 1 redistribute eigrp 1 metric 20 subnets network 0.0.0.0 255.255.255.255 area 1 ! router eigrp 1 network 10.3.4.0 0.0.0.255 |
| R2513 |
interface GigabitEthernet0/0 ip address 10.3.4.4 255.255.255.0 ! interface GigabitEthernet0/1 ip address 10.200.1.4 255.255.255.0 ! router eigrp 1 network 10.3.4.0 0.0.0.255 network 10.200.1.0 0.0.0.255 |
R2507#show ip ospf database external 10.200.1.0 OSPF Router with ID (10.7.7.1) (Process ID 1) Type-5 AS External Link States LS age: 954 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 10.200.1.0 (External Network Number ) Advertising Router: 10.44.66.3 LS Seq Number: 80000007 Checksum: 0x46EF Length: 36 Network Mask: /24 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 20 Forward Address: 10.3.4.4 External Route Tag: 0
R2507的資料庫中包含10.200.1.0/24，但它尚未將其安裝在路由表中，因為通過OSPF外部路由獲知10.3.4.4。
R2507#show ip route 10.3.4.4
Routing entry for 10.3.4.0/24
Known via "ospf 1", distance 110, metric 20,type extern 2, forward metric 70
Redistributing via ospf 1
Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:40 ago
Routing Descriptor Blocks:
* 10.1.1.2, from 10.44.66.3, 00:00:40 ago, via GigabitEthernet0/0
Route metric is 20, traffic share count is 1
修正提及的錯誤後，輸出如下所示：
R2507#show ip route 10.3.4.4 Routing entry for 10.0.0.0/8 Known via "ospf 1", distance 110, metric 2, type inter area Last update from 10.1.1.2 on GigabitEthernet0/0, 00:01:02 ago Routing Descriptor Blocks: * 10.1.1.2, from 10.3.4.2, 00:01:02 ago, via GigabitEthernet0/0 Route metric is 2, traffic share count is 1R2507#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 10.7.7.2 to network 0.0.0.0 S* 0.0.0.0/0 [1/0] via 10.7.7.2 10.0.0.0/8 is variably subnetted, 6 subnets, 3 masks O IA 10.0.0.0/8 [110/2] via 10.1.1.2, 00:01:41, GigabitEthernet0/0 C 10.1.1.0/24 is directly connected, GigabitEthernet0/0 L 10.1.1.1/32 is directly connected, GigabitEthernet0/0 C 10.7.7.0/24 is directly connected, GigabitEthernet0/1 L 10.7.7.1/32 is directly connected, GigabitEthernet0/1 O E2 10.200.1.0/24 [110/20] via 10.1.1.2, 03:30:47, GigabitEthernet0/0
如果轉發地址也通過外部路由得知，OSPF不會將該路由安裝到路由表中。有關此問題的更多詳細資訊，請參閱OSPF轉發地址的常見路由問題。
原因7：路由被分發清單阻止
下一個網路圖用作示例：
| R4-4K | R1-7010 |
|---|---|
interface Loopback0 ip address 172.16.33.1 255.255.255.255 ! interface Serial2 ip address 172.16.32.1 255.255.255.0 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 |
interface Loopback0 ip address 172.16.30.1 255.255.255.255 ! interface Serial1/0 ip address 172.16.32.2 255.255.255.0 clockrate 64000 ! router ospf 20 network 172.16.0.0 0.0.255.255 area 0 distribute-list 1 in ! access-list 1 permit 172.16.32.0. 0.0.0.255 |
如前所述，R1-7010配置了distribute-list命令，它僅允許在路由表中安裝172.16.32.0/24地址範圍。在鏈路狀態協定中，您實際上無法使用distribute-list命令篩選LSA。LSA仍存在於資料庫中；但是LSA未安裝在路由表中。
R1-7010(5)#show ip ospf database router 172.16.33.1
LS age: 357
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.16.33.1
Advertising Router: 172.16.33.1
LS Seq Number: 8000000A
Checksum: 0xD4AA
Length: 48
Number of Links: 3
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 172.16.32.2
(Link Data) Router Interface address: 172.16.32.1
Number of TOS metrics: 0
TOS 0 Metrics: 64
R1-7010上的distribute-list配置命令過濾172.16.33.1/32網路並阻止將子網安裝到路由表中。
R1-7010(5)#show ip route 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks C 172.16.32.0/24 is directly connected, Serial1/0 C 172.16.30.1/32 is directly connected, Loopback0
解決方案
要解決此問題，請在訪問控制清單(ACL)中配置R1-7010並允許172.16.33.0/24，以便將此網路安裝到路由表中。
R1-7010(5)#configure terminal
R1-7010(5)(config)#access-list 1 permit 172.16.33.0 0.0.0.255
R1-7010(5)(config)#end
R1-7010(5)#show ip access-list 1
Standard IP access list 1
permit 172.16.32.0, wildcard bits 0.0.0.255
permit 172.16.33.0, wildcard bits 0.0.0.255
R1-7010(5)#show ip route
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
C 172.16.32.0/24 is directly connected, Serial1/0
O 172.16.33.1/32 [110/65] via 172.16.32.1, 00:00:08, Serial1/0
C 172.16.30.1/32 is directly connected, Loopback0
相關資訊
修訂記錄
| 修訂 | 發佈日期 | 意見 |
|---|---|---|
3.0 |
28-Aug-2023 |
重新認證 |
2.0 |
25-Jul-2022 |
初始版本 |
1.0 |
05-Nov-2001 |
初始版本 |
意見