使用Route-policy控制路由
拓撲圖
實驗過程
IP地址選配
| 設備名稱 | 接口 | ip地址 | 網關 |
|---|---|---|---|
| PCA | – | 10.0.1.2/24 | 10.0.1.1 |
| PCB | – | 10.0.2.2/24 | 10.0.2.1 |
| RTA | G0/0 | 10.0.1.1/24 | – |
| S5/0 | 192.168.1.1/30 | – | |
| S5/1 | 192.168.1.5/30 | – | |
| RTB | S5/0 | 192.168.1.2/30 | – |
| S5/1 | 192.168.2.1/30 | – | |
| RTC | S5/0 | 192.168.1.6/30 | – |
| S5/1 | 192.168.2.5/30 | – | |
| RTD | G0/0 | 10.0.2.1/24 | – |
| S5/0 | 192.168.2.2/30 | – | |
| S5/1 | 192.168.2.6/30 | – |
在pc及路由上配置ip地址。
設置PC IP
PCA
PCB
基本配置
RTA
<H3C>sys
<H3C>system-view
System View: return to User View with Ctrl+Z.
[H3C]hostname RTA
[RTA]int g0/0
[RTA-GigabitEthernet0/0]ip add 10.0.1.1 24
[RTA-GigabitEthernet0/0]no shu
[RTA-GigabitEthernet0/0]no shutdown
[RTA-GigabitEthernet0/0]exit
[RTA]int g5/0
[RTA-GigabitEthernet5/0]ip add 192.168.1.1 30
[RTA-GigabitEthernet5/0]no shutdown
[RTA-GigabitEthernet5/0]exit
[RTA]int g5/1
[RTA-GigabitEthernet5/1]ip add 192.168.1.5 30
[RTA-GigabitEthernet5/1]no shutdown
[RTA-GigabitEthernet5/1]exit
[RTA]
RTB
<H3C>SYS
<H3C>system-view
System View: return to User View with Ctrl+Z.
[H3C]hostname RTB
[RTB]int g5/0
[RTB-GigabitEthernet5/0]ip add 192.168.1.2 30
[RTB-GigabitEthernet5/0]no shu
[RTB-GigabitEthernet5/0]no shutdown
[RTB-GigabitEthernet5/0]exi
[RTB-GigabitEthernet5/0]exit
[RTB]int g5/1
[RTB-GigabitEthernet5/1]ip add 192.168.2.1 30
[RTB-GigabitEthernet5/1]no shu
[RTB-GigabitEthernet5/1]no shutdown
[RTB-GigabitEthernet5/1]exi
[RTB-GigabitEthernet5/1]exit
[RTB]
RTC
[H3C]hostname RTC
[RTC]int g5/0
[RTC-GigabitEthernet5/0]ip add 192.168.1.6 30
[RTC-GigabitEthernet5/0]no shu
[RTC-GigabitEthernet5/0]no shutdown
[RTC-GigabitEthernet5/0]exi
[RTC-GigabitEthernet5/0]exit
[RTC]int g5/1
[RTC-GigabitEthernet5/1]ip add 192.168.2.5 30
[RTC-GigabitEthernet5/1]no shu
[RTC-GigabitEthernet5/1]no shutdown
[RTC-GigabitEthernet5/1]exi
[RTC-GigabitEthernet5/1]exit
[RTC]
RTD
[H3C]hostname RTD
[RTD]int g0/0
[RTD-GigabitEthernet0/0]ip add 10.0.2.1 24
[RTD-GigabitEthernet0/0]no shu
[RTD-GigabitEthernet0/0]no shutdown
[RTD-GigabitEthernet0/0]exi
[RTD-GigabitEthernet0/0]exit
[RTD]int g5/0
[RTD-GigabitEthernet5/0]ip add 192.168.2.2 30
[RTD-GigabitEthernet5/0]no shu
[RTD-GigabitEthernet5/0]no shutdown
[RTD-GigabitEthernet5/0]exi
[RTD-GigabitEthernet5/0]exit
[RTD]int g5/1
[RTD-GigabitEthernet5/1]ip add 192.168.2.6 30
[RTD-GigabitEthernet5/1]no shu
[RTD-GigabitEthernet5/1]no shutdown
[RTD-GigabitEthernet5/1]exi
[RTD-GigabitEthernet5/1]exit
[RTD]
引入靜態路由
在路由器RTA、RTB、RTC上啓用RIPV2進行路由學習，並將RTB和RTC的接口s5/0的路由發佈，再RTA上配置靜態路由10.1.0.0/24 和10.1.1.0/24，並將靜態路由引入到rip協議中，並將所引入的路由缺省度量值改爲2
。
配置RTA
[RTA]ip route-static 10.1.0.0 24 10.0.1.2
[RTA]ip route-static 10.1.1.0 24 10.0.1.2
[RTA]rip
[RTA-rip-1]network 10.0.0.0
[RTA-rip-1]network 192.168.1.0
[RTA-rip-1]version 2
[RTA-rip-1]undo summary
[RTA-rip-1]import-route static
[RTA-rip-1]default cost 2
[RTA-rip-1]
配置RTB
[RTB]rip
[RTB-rip-1]ne
[RTB-rip-1]network 192.168.1.0
[RTB-rip-1]ve
[RTB-rip-1]version 2
[RTB-rip-1]un
[RTB-rip-1]undo sum
[RTB-rip-1]undo summary
[RTB-rip-1]
配置RTC
[RTC]rip
[RTC-rip-1]network 192.168.1.0
[RTC-rip-1]version 2
[RTC-rip-1]undo summary
[RTC-rip-1]
配置完成之後在RTB和RTC上查看路由表，如下所示：
[RTB]dis ip routing-table
Destinations : 20 Routes : 20
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 RIP 100 1 192.168.1.1 GE5/0
10.1.0.0/24 RIP 100 3 192.168.1.1 GE5/0
10.1.1.0/24 RIP 100 3 192.168.1.1 GE5/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.2 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.2 GE5/0
192.168.1.2/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.2 GE5/0
192.168.1.4/30 RIP 100 1 192.168.1.1 GE5/0
192.168.2.0/30 Direct 0 0 192.168.2.1 GE5/1
192.168.2.0/32 Direct 0 0 192.168.2.1 GE5/1
192.168.2.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.3/32 Direct 0 0 192.168.2.1 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTB]
[RTC]dis ip routing-table
Destinations : 20 Routes : 20
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 RIP 100 1 192.168.1.5 GE5/0
10.1.0.0/24 RIP 100 3 192.168.1.5 GE5/0
10.1.1.0/24 RIP 100 3 192.168.1.5 GE5/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 RIP 100 1 192.168.1.5 GE5/0
192.168.1.4/30 Direct 0 0 192.168.1.6 GE5/0
192.168.1.4/32 Direct 0 0 192.168.1.6 GE5/0
192.168.1.6/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.7/32 Direct 0 0 192.168.1.6 GE5/0
192.168.2.4/30 Direct 0 0 192.168.2.5 GE5/1
192.168.2.4/32 Direct 0 0 192.168.2.5 GE5/1
192.168.2.5/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.7/32 Direct 0 0 192.168.2.5 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTC]
可見RTA將引入的路由10.1.0.0/24和10.1.1.0/24發佈給RTB和RTC，度量值爲3（缺省度量值再加1）
引入的路由過濾
配置引入路由後，所有的靜態路由都獎引入到RIP路由表中，爲了有選擇性的引入所需要的路由，可以在RTA上配置ROUTE-POLICY，將引入路由10.1.0.0/24.
配置RTA
[RTA]ip prefix-list abc index 10 permit 10.1.0.0 24
[RTA]route-policy abc permit node 10
[RTA-route-policy-abc-10]if-match ip address prefix-list abc
[RTA-route-policy-abc-10]quit
[RTA]rip
[RTA-rip-1]import-route static route-policy abc
配置完成後，查看RTB和RTC的路由表，如下表示：
[RTB]dis ip routing-table
Destinations : 19 Routes : 19
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 RIP 100 1 192.168.1.1 GE5/0
10.1.0.0/24 RIP 100 3 192.168.1.1 GE5/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.2 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.2 GE5/0
192.168.1.2/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.2 GE5/0
192.168.1.4/30 RIP 100 1 192.168.1.1 GE5/0
192.168.2.0/30 Direct 0 0 192.168.2.1 GE5/1
192.168.2.0/32 Direct 0 0 192.168.2.1 GE5/1
192.168.2.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.3/32 Direct 0 0 192.168.2.1 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTB]
[RTC]dis ip routing-table
Destinations : 19 Routes : 19
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 RIP 100 1 192.168.1.5 GE5/0
10.1.0.0/24 RIP 100 3 192.168.1.5 GE5/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 RIP 100 1 192.168.1.5 GE5/0
192.168.1.4/30 Direct 0 0 192.168.1.6 GE5/0
192.168.1.4/32 Direct 0 0 192.168.1.6 GE5/0
192.168.1.6/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.7/32 Direct 0 0 192.168.1.6 GE5/0
192.168.2.4/30 Direct 0 0 192.168.2.5 GE5/1
192.168.2.4/32 Direct 0 0 192.168.2.5 GE5/1
192.168.2.5/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.7/32 Direct 0 0 192.168.2.5 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTC]
可以看到RTB、RTC路由表沒有了RTA上的10.1.1.0/24路由，因爲RTA在引入時，可以把它過濾掉了。
OSPF路由配置
在RTB、RTC和RTD上配置OSPF單區域，規劃區域爲0，並將RTB和RTC的接口在S5/1的路由發佈
配置RTB
[RTB]ospf
[RTB-ospf-1]ar
[RTB-ospf-1]area 0
[RTB-ospf-1-area-0.0.0.0]ne
[RTB-ospf-1-area-0.0.0.0]network 192.168.2.0 0.0.0.3
[RTB-ospf-1-area-0.0.0.0]
配置RTC
[RTC]OSPF
[RTC-ospf-1]area 0
[RTC-ospf-1-area-0.0.0.0]network 192.168.2.4 0.0.0.3
[RTC-ospf-1-area-0.0.0.0]
配置RTD
[RTD]ospf
[RTD-ospf-1]a
[RTD-ospf-1]area 0
[RTD-ospf-1-area-0.0.0.0]network 10.0.2.0 0.0.0.255
[RTD-ospf-1-area-0.0.0.0]network 192.168.2.0 0.0.0.3
[RTD-ospf-1-area-0.0.0.0]network 192.168.2.4 0.0.0.3
配置完成之後，查看RTA和RTD的路由表，如下所示：
[RTA]dis ip routing-table
Destinations : 22 Routes : 22
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 Direct 0 0 10.0.1.1 GE0/0
10.0.1.0/32 Direct 0 0 10.0.1.1 GE0/0
10.0.1.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.255/32 Direct 0 0 10.0.1.1 GE0/0
10.1.0.0/24 Static 60 0 10.0.1.2 GE0/0
10.1.1.0/24 Static 60 0 10.0.1.2 GE0/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.1 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.4/30 Direct 0 0 192.168.1.5 GE5/1
192.168.1.4/32 Direct 0 0 192.168.1.5 GE5/1
192.168.1.5/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.7/32 Direct 0 0 192.168.1.5 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTA]
[RTD]dis ip routing-table
Destinations : 20 Routes : 20
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.2.0/24 Direct 0 0 10.0.2.1 GE0/0
10.0.2.0/32 Direct 0 0 10.0.2.1 GE0/0
10.0.2.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.2.255/32 Direct 0 0 10.0.2.1 GE0/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.0/30 Direct 0 0 192.168.2.2 GE5/0
192.168.2.0/32 Direct 0 0 192.168.2.2 GE5/0
192.168.2.2/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.3/32 Direct 0 0 192.168.2.2 GE5/0
192.168.2.4/30 Direct 0 0 192.168.2.6 GE5/1
192.168.2.4/32 Direct 0 0 192.168.2.6 GE5/1
192.168.2.6/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.7/32 Direct 0 0 192.168.2.6 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTD]
RTA上沒有路由10.0.2.0/24，RTD上沒有路由10.0.1.0/24和10.1.0.0/24.
配置雙邊界引入
在RTB和RTC 上配置雙邊界引入，分別將ospf和rip的路由引入對方，其中，配置rtb將opsf路由引入到rip中，配置rtc將rip引入到ospf中。
配置RTB
[RTB]rip
[RTB-rip-1]import-route ospf
[RTB-rip-1]
配置RTC
[RTc]ospf
[RTC-ospf-1]import-route rip
配置完成後，再查看RTA和RTD的路由表，如下表示：
[RTA]dis ip routing-table
Destinations : 24 Routes : 24
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 Direct 0 0 10.0.1.1 GE0/0
10.0.1.0/32 Direct 0 0 10.0.1.1 GE0/0
10.0.1.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.255/32 Direct 0 0 10.0.1.1 GE0/0
10.0.2.0/24 RIP 100 1 192.168.1.2 GE5/0
10.1.0.0/24 Static 60 0 10.0.1.2 GE0/0
10.1.1.0/24 Static 60 0 10.0.1.2 GE0/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.1 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.4/30 Direct 0 0 192.168.1.5 GE5/1
192.168.1.4/32 Direct 0 0 192.168.1.5 GE5/1
192.168.1.5/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.7/32 Direct 0 0 192.168.1.5 GE5/1
192.168.2.4/30 RIP 100 1 192.168.1.2 GE5/0
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTA]
[RTD]dis ip routing-table
Destinations : 23 Routes : 23
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 O_ASE2 150 1 192.168.2.5 GE5/1
10.0.2.0/24 Direct 0 0 10.0.2.1 GE0/0
10.0.2.0/32 Direct 0 0 10.0.2.1 GE0/0
10.0.2.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.2.255/32 Direct 0 0 10.0.2.1 GE0/0
10.1.0.0/24 O_ASE2 150 1 192.168.2.5 GE5/1
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 O_ASE2 150 1 192.168.2.5 GE5/1
192.168.2.0/30 Direct 0 0 192.168.2.2 GE5/0
192.168.2.0/32 Direct 0 0 192.168.2.2 GE5/0
192.168.2.2/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.3/32 Direct 0 0 192.168.2.2 GE5/0
192.168.2.4/30 Direct 0 0 192.168.2.6 GE5/1
192.168.2.4/32 Direct 0 0 192.168.2.6 GE5/1
192.168.2.6/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.7/32 Direct 0 0 192.168.2.6 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTD]
RTA上學到了路由10.0.2.0/24，RTD上也學到了路由10.0.1.0/24和10.1.0.0/24.
路由環路產生
配置路由邊界中後，在某些情況下可能會導致路由環路或者錯誤。下面我們人爲地製造這個環路。在RTA上將靜態路由由10.1.0.0/24的優先級改爲120.
配置RTC
[RTA]ip route-static 10.1.0.0 24 10.0.1.2 preference 120
然後在RTB上將rip協議的優先級改爲200，以使RTB能夠將從RTD學到10.1.0.0/24路由向rip域內發佈。
配置RTB
[RTB]rip
[RTB-rip-1]preference 200
[RTA]dis ip routing-table
Destinations : 25 Routes : 26
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 Direct 0 0 10.0.1.1 GE0/0
10.0.1.0/32 Direct 0 0 10.0.1.1 GE0/0
10.0.1.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.255/32 Direct 0 0 10.0.1.1 GE0/0
10.0.2.0/24 RIP 100 1 192.168.1.2 GE5/0
192.168.1.6 GE5/1
10.1.0.0/24 RIP 100 1 192.168.1.2 GE5/0
10.1.1.0/24 Static 60 0 10.0.1.2 GE0/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.1 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.4/30 Direct 0 0 192.168.1.5 GE5/1
192.168.1.4/32 Direct 0 0 192.168.1.5 GE5/1
192.168.1.5/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.7/32 Direct 0 0 192.168.1.5 GE5/1
192.168.2.0/30 RIP 100 1 192.168.1.6 GE5/1
192.168.2.4/30 RIP 100 1 192.168.1.2 GE5/0
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTA]
[RTB]dis ip routing-table
Destinations : 21 Routes : 21
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 O_ASE2 150 1 192.168.2.2 GE5/1
10.0.2.0/24 O_INTRA 10 2 192.168.2.2 GE5/1
10.1.0.0/24 O_ASE2 150 1 192.168.2.2 GE5/1
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.2 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.2 GE5/0
192.168.1.2/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.2 GE5/0
192.168.1.4/30 RIP 200 1 192.168.1.1 GE5/0
192.168.2.0/30 Direct 0 0 192.168.2.1 GE5/1
192.168.2.0/32 Direct 0 0 192.168.2.1 GE5/1
192.168.2.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.3/32 Direct 0 0 192.168.2.1 GE5/1
192.168.2.4/30 O_INTRA 10 2 192.168.2.2 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTB]
可見，錯誤出現了，RTA以爲通過了RTB能到10.1.0.0/24，而RTB以爲通過RTD能到10.1.0.0/24，RTD以爲能通過RTC到10.1.0.0/24，RTC又以爲通過RTA能到10.1.0.0/24。
路由環路發生了。在RTA在查到到達 10.1.0.0/24 的路徑，如下所示：
<RTA>tra
<RTA>tracert 10.1.0.1
traceroute to 10.1.0.1 (10.1.0.1), 30 hops at most, 40 bytes each packet, press CTRL_C to break
1 * * *
2 * * *
3 * * *
4 * *
[RTD]dis ip routing-table
Destinations : 23 Routes : 23
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 O_ASE2 150 1 192.168.2.5 GE5/1
10.0.2.0/24 Direct 0 0 10.0.2.1 GE0/0
10.0.2.0/32 Direct 0 0 10.0.2.1 GE0/0
10.0.2.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.2.255/32 Direct 0 0 10.0.2.1 GE0/0
10.1.0.0/24 O_ASE2 150 1 192.168.2.5 GE5/1
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 O_ASE2 150 1 192.168.2.5 GE5/1
192.168.2.0/30 Direct 0 0 192.168.2.2 GE5/0
192.168.2.0/32 Direct 0 0 192.168.2.2 GE5/0
192.168.2.2/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.3/32 Direct 0 0 192.168.2.2 GE5/0
192.168.2.4/30 Direct 0 0 192.168.2.6 GE5/1
192.168.2.4/32 Direct 0 0 192.168.2.6 GE5/1
192.168.2.6/32 Direct 0 0 127.0.0.1 InLoop0
192.168.2.7/32 Direct 0 0 192.168.2.6 GE5/1
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
[RTD]
使用TAG選擇性引入路由
[RTA]rip
[RTA-rip-1]import-route ospf tag 10
[RTA-rip-1]quit
[RTB]route-policy abc deny node 10
[RTB-route-policy-abc-10]if-match tag 10
[RTB-route-policy-abc-10]qui
[RTB-route-policy-abc-10]quit
[RTB]route-policy abc permit node 20
[RTB-route-policy-abc-20]quit
[RTB]rip
[RTB-rip-1]import-route ospf route-policy abc
[RTB-rip-1]
<RTA>dis ip routing-table
Destinations : 25 Routes : 26
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.0/24 Direct 0 0 10.0.1.1 GE0/0
10.0.1.0/32 Direct 0 0 10.0.1.1 GE0/0
10.0.1.1/32 Direct 0 0 127.0.0.1 InLoop0
10.0.1.255/32 Direct 0 0 10.0.1.1 GE0/0
10.0.2.0/24 RIP 100 1 192.168.1.2 GE5/0
192.168.1.6 GE5/1
10.1.0.0/24 RIP 100 1 192.168.1.2 GE5/0
10.1.1.0/24 Static 120 0 10.0.1.2 GE0/0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
127.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.0/30 Direct 0 0 192.168.1.1 GE5/0
192.168.1.0/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.1/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.3/32 Direct 0 0 192.168.1.1 GE5/0
192.168.1.4/30 Direct 0 0 192.168.1.5 GE5/1
192.168.1.4/32 Direct 0 0 192.168.1.5 GE5/1
192.168.1.5/32 Direct 0 0 127.0.0.1 InLoop0
192.168.1.7/32 Direct 0 0 192.168.1.5 GE5/1
192.168.2.0/30 RIP 100 1 192.168.1.6 GE5/1
192.168.2.4/30 RIP 100 1 192.168.1.2 GE5/0
224.0.0.0/4 Direct 0 0 0.0.0.0 NULL0
224.0.0.0/24 Direct 0 0 0.0.0.0 NULL0
255.255.255.255/32 Direct 0 0 127.0.0.1 InLoop0
<RTA>
可以看到，路由10.1.0.0/24被過濾，所以RTA上僅有靜態路由了。