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Cisco ❀ 双向双点重发布

双向双点重发布的基础应用实验

Cisco ❀ 双向双点重发布_Cisco
拓普要求:
(1)在R1、R2、R4上建立RIP V2的动态协议(R2的loopback 1在RIP V2中)
(2)在R2、R3、R4上建立OSPF的动态协议,其区域为骨干区域(R4的loopback 1在OSPF的骨干区域内)
(3)在R2与R4上进行双向重发布
(RIP V2中重发布OSPF,OSPF中重发布RIP V2)
此效果必然会产生次优路径或者产生环路

我们下面要做的是解决次优路径与环路问题:
1、IP地址具体规划:
该拓扑的IPV4地址如下(IP地址可以自行设定):
R1的loopback 1的IPV4地址为1.1.1.1/32
R2的loopback 1的IPV4地址为2.2.2.2/32
R3的loopback 1的IPV4地址为3.3.3.3/32
R4的loopback 1的IPV4地址为4.4.4.4/32
R1-R2的S1/1接口的IPV4地址为12.1.1.1/24
R2-R1的S1/0接口的IPV4地址为12.1.1.2/24
R2-R3的S1/1接口的IPV4地址为23.1.1.1/24
R3-R2的S1/0接口的IPV4地址为23.1.1.2/24
R3-R4的S1/1接口的IPV4地址为34.1.1.1/24
R4-R3的S1/0接口的IPV4地址为34.1.1.2/24
R1-R4的E0/0接口的IPV4地址为14.1.1.1/24
R4-R1的E0/0接口的IPV4地址为14.1.1.2/24

2、给接口配置IPV4地址:

R1(config)#int l1
R1(config-if)#ip aadd
R1(config-if)#ip address 1.1.1.1 255.255.255.255
R1(config-if)#no shutdown//环回接口可以不使用,链路接口必须开启
R1(config-if)#exit

首先对所有路由器进行配置:

Router>en
Router#conf t
Router(config)#line c 0
Router(config-line)#exec-t 0 0
Router(config-line)#logg synchronous
Router(config-line)#no ip domain-lo
Router(config)#ho RX //RX为路由器编号,例如R1/R2/R3/R4

3、搭建RIP环境
R1的RIP V2配置:

R1(config)#router rip 
R1(config-router)#version 2
R1(config-router)#no auto-summary//建议关闭自动汇总
R1(config-router)#network 1.0.0.0
R1(config-router)#network 12.0.0.0
R1(config-router)#network 14.0.0.0
R1(config-router)#exit

R2的RIP V2配置:

R2(config)#router rip 
R2(config-router)#version 2
R2(config-router)#no auto-summary
R2(config-router)#network 2.0.0.0
R2(config-router)#network 12.0.0.0
R2(config-router)#exit

R3的RIP V2配置:

R4(config)#router rip
R4(config-router)#version 2
R4(config-router)#no auto-summary
R4(config-router)#network 14.0.0.0
R4(config-router)#exit

4、搭建OSPF环境:
R2的OSPF配置:

R2(config)#router ospf 100
R2(config-router)#router-id 2.2.2.2 (OSPF的router-id具有本地唯一性)
R2(config-router)#network 23.1.1.0 0.0.0.255 area 0 (骨干区域为area 0
R2(config-router)#exit

R3的OSPF配置:

R3(config)#router ospf 100
R3(config-router)#router-id 3.3.3.3
R3(config-router)#network 3.3.3.0 0.0.0.255 area 0
R3(config-router)#network 23.1.1.0 0.0.0.255 area 0
R3(config-router)#network 34.1.1.0 0.0.0.255 area 0
R3(config-router)#exit

R4的OSPF配置:

R4(config-if)#router os 100
R4(config-router)#router-id 4.4.4.4
R4(config-router)#network 4.4.4.0 0.0.0.255 area 0
R4(config-router)#network 34.1.1.0 0.0.0.255 area 0
R4(config-router)#exit

配置完成后可以在R1与R3上查看路由,R1上存在R2的loopback 1路由,R3上存在R4的loopback 1路由:

R1(config)#do show ip route rip
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/1] via 12.1.1.2, 00:00:27, Serial1/1
R3(config)#do show ip route ospf
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 34.1.1.2, 00:00:18, Serial1/1

5、在R2/R4上进行双向重发布配置:
R2的配置:

R2(config)#router rip 
R2(config-router)#redistribute ospf 100 metric 1//将OSPF中的静态路由重发布到RIP V2中,其metric为1
R2(config-router)#exit

R2(config)#router ospf 100
R2(config-router)#redistribute rip subnets//将RIP V2的路由重发布到OSPF中

R4的配置:

R4(config)#router rip 
R4(config-router)#redistribute ospf 100 metric 1
R4(config-router)#exit

R4(config)#router ospf 100
R4(config-router)#redistribute rip subnets

可以使用此命令刷新路由表

R1#clear ip route *

6、此时R1/R2/R3/R4上将会产生次优路径:

(1)修改R4上的次优路径:

R4#show ip route
34.0.0.0/24 is subnetted, 1 subnets
C 34.1.1.0 is directly connected, Serial1/0
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 14.1.1.1, 00:00:04, FastEthernet0/0
2.0.0.0/32 is subnetted, 1 subnets
O E2 2.2.2.2 [110/20] via 34.1.1.1, 00:01:27, Serial1/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 34.1.1.1, 00:01:27, Serial1/0
4.0.0.0/32 is subnetted, 1 subnets
C 4.4.4.4 is directly connected, Loopback1
23.0.0.0/24 is subnetted, 1 subnets
O 23.1.1.0 [110/128] via 34.1.1.1, 00:01:27, Serial1/0
12.0.0.0/24 is subnetted, 1 subnets
O E2 12.1.1.0 [110/20] via 34.1.1.1, 00:00:11, Serial1/0
14.0.0.0/24 is subnetted, 1 subnets
C 14.1.1.0 is directly connected, FastEthernet0/0

此时OE 2的路由均为次优路由
次优路由的产生原因:2.2.2.2/32的路由由RIP V2发布,其AD值为120,在R2上进行重发布到OSPF中,此时的OSPF中2.2.2.2/32路由类型为OE2,其路由的AD值为110,由于路由选择先考虑其AD值,AD值越小路由越优,所以此时路由表会加载OSPF OE2的路由,造成了次优路径的问题(12.1.1.0/24与此相同)

解决办法:
在OSPF中直接修改个别重发布路由的AD值或者修改其所有重发布路由的AD值

R4(config)#router ospf 100
R4(config-router)#distance 121 2.2.2.2 0.0.0.0//此意思为router-id为2.2.2.2的路由器所发布的OSPF路由的AD值为121

121为修改后的AD值;2.2.2.2为修改的router-id;0.0.0.0为反掩码

修改完成后,此时还会存在次优路径

2.0.0.0/32 is subnetted, 1 subnets
O E2 2.2.2.2 [121/20] via 34.1.1.1, 00:01:20, Serial1/0

由于AD值为121,证明上面的修改AD值已经生效,此时仍为次优路径的原因是:
R4在收到R2所发布的AD值为121的2.2.2.2/32路由时将其重发布给R1,当R1从F0/0接口接收到AD值为121的2.2.2.2/32路由,并且R1从S1/1接口接收到AD值为120的2.2.2.2/32路由时,R1不会将S1/1收到的AD值为120的2.2.2.2/32路由从F0/0转发给R4

解决方法:在R1上使用ACL抓取感兴趣流量(2.2.2.2/32路由),并且在RIP V2中使用offset-list进行加mitric来修改选路

R1(config)#access-list 1 permit 2.2.2.0 0.0.0.255

R1(config)#router rip
R1(config-router)#offset-list 1 in 3 f0/0

完成之后,对路由表进行刷新

34.0.0.0/24 is subnetted, 1 subnets
C 34.1.1.0 is directly connected, Serial1/0
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 14.1.1.1, 00:00:03, FastEthernet0/0
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/2] via 14.1.1.1, 00:00:03, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 34.1.1.1, 00:03:40, Serial1/0
4.0.0.0/24 is subnetted, 1 subnets
C 4.4.4.0 is directly connected, Loopback1
23.0.0.0/24 is subnetted, 1 subnets
O 23.1.1.0 [110/128] via 34.1.1.1, 00:03:40, Serial1/0
12.0.0.0/24 is subnetted, 1 subnets
R 12.1.1.0 [120/1] via 14.1.1.1, 00:00:03, FastEthernet0/0
14.0.0.0/24 is subnetted, 1 subnets
C 14.1.1.0 is directly connected, FastEthernet0/0

此时R4的路由表全为最优路由

(2)修改R2的次优路径:

R2#show ip route
34.0.0.0/24 is subnetted, 1 subnets
O 34.1.1.0 [110/128] via 23.1.1.2, 00:05:18, Serial1/1
1.0.0.0/32 is subnetted, 1 subnets
O E2 1.1.1.1 [110/20] via 23.1.1.2, 00:05:18, Serial1/1
2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback1
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 23.1.1.2, 00:05:18, Serial1/1
4.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O 4.4.4.4/32 [110/129] via 23.1.1.2, 00:05:18, Serial1/1
R 4.4.4.0/24 [120/2] via 12.1.1.1, 00:00:06, Serial1/0
23.0.0.0/24 is subnetted, 1 subnets
C 23.1.1.0 is directly connected, Serial1/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial1/0
14.0.0.0/24 is subnetted, 1 subnets
O E2 14.1.1.0 [110/20] via 23.1.1.2, 00:05:19, Serial1/1

其中OE 2类型的OSPF路由均为次优路由
解决办法:
在OSPF中直接修改个别重发布路由的AD值或者修改其所有重发布路由的AD值

R4(config)#router ospf 100
R4(config-router)#distance 121 4.4.4.4 0.0.0.0

完成之后刷新路由表:

34.0.0.0/24 is subnetted, 1 subnets
O 34.1.1.0 [110/128] via 23.1.1.2, 00:00:02, Serial1/1
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 12.1.1.1, 00:00:00, Serial1/0
2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback1
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 23.1.1.2, 00:00:02, Serial1/1
4.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O 4.4.4.4/32 [121/129] via 23.1.1.2, 00:00:02, Serial1/1
R 4.4.4.0/24 [120/2] via 12.1.1.1, 00:00:00, Serial1/0
23.0.0.0/24 is subnetted, 1 subnets
C 23.1.1.0 is directly connected, Serial1/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial1/0
14.0.0.0/24 is subnetted, 1 subnets
R 14.1.1.0 [120/1] via 12.1.1.1, 00:00:01, Serial1/0

此时R2的路由表全为最优路由

(3)修改R1的次优路径:

R1#show ip route
34.0.0.0/24 is subnetted, 1 subnets
R 34.1.1.0 [120/1] via 14.1.1.2, 00:00:00, FastEthernet0/0
[120/1] via 12.1.1.2, 00:00:00, Serial1/1
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback1
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/1] via 12.1.1.2, 00:00:00, Serial1/1
3.0.0.0/32 is subnetted, 1 subnets
R 3.3.3.3 [120/1] via 14.1.1.2, 00:00:00, FastEthernet0/0
[120/1] via 12.1.1.2, 00:00:00, Serial1/1
4.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
R 4.4.4.4/32 [120/1] via 12.1.1.2, 00:00:00, Serial1/1
R 4.4.4.0/24 [120/1] via 14.1.1.2, 00:00:00, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
R 23.1.1.0 [120/1] via 14.1.1.2, 00:00:01, FastEthernet0/0
[120/1] via 12.1.1.2, 00:00:01, Serial1/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial1/1
14.0.0.0/24 is subnetted, 1 subnets
C 14.1.1.0 is directly connected, FastEthernet0/0

7、设置负载均衡
由于R1-R3的路径可以负载均衡,其余的负载均衡都是不正确的路由

解决方法:使用ACL抓取感兴趣流量(23.1.1.0/24与34.1.1.0/24),使用offset-list进行加metric进行修改

R1(config)#access-list 5 permit 23.1.1.0 0.0.0.255
R1(config)#access-list 10 permit 34.1.1.0 0.0.0.255

R1(config)#router rip
R1(config-router)#of
R1(config-router)#offset-list 5 in 3 f0/0
R1(config-router)#offset-list 10 in 3 s1/1

完成之后,刷新路由表:

34.0.0.0/24 is subnetted, 1 subnets
R 34.1.1.0 [120/1] via 14.1.1.2, 00:00:02, FastEthernet0/0
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback1
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/1] via 12.1.1.2, 00:00:02, Serial1/1
3.0.0.0/32 is subnetted, 1 subnets
R 3.3.3.3 [120/1] via 14.1.1.2, 00:00:02, FastEthernet0/0
[120/1] via 12.1.1.2, 00:00:02, Serial1/1
4.0.0.0/32 is subnetted, 1 subnets
R 4.4.4.4 [120/1] via 14.1.1.2, 00:00:02, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
R 23.1.1.0 [120/1] via 12.1.1.2, 00:00:02, Serial1/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial1/1
14.0.0.0/24 is subnetted, 1 subnets
C 14.1.1.0 is directly connected, FastEthernet0/0

此时的R1路由表全为最优路由

(4)修改R3的次优路由:

R3#show ip route 
34.0.0.0/24 is subnetted, 1 subnets
C 34.1.1.0 is directly connected, Serial1/1
1.0.0.0/32 is subnetted, 1 subnets
O E2 1.1.1.1 [110/20] via 34.1.1.2, 00:08:29, Serial1/1
[110/20] via 23.1.1.1, 00:08:29, Serial1/0
2.0.0.0/32 is subnetted, 1 subnets
O E2 2.2.2.2 [110/20] via 34.1.1.2, 00:08:29, Serial1/1
[110/20] via 23.1.1.1, 00:08:29, Serial1/0
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback1
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 34.1.1.2, 00:07:26, Serial1/1
23.0.0.0/24 is subnetted, 1 subnets
C 23.1.1.0 is directly connected, Serial1/0
12.0.0.0/24 is subnetted, 1 subnets
O E2 12.1.1.0 [110/20] via 34.1.1.2, 00:08:30, Serial1/1
[110/20] via 23.1.1.1, 00:08:30, Serial1/0
14.0.0.0/24 is subnetted, 1 subnets
O E2 14.1.1.0 [110/20] via 34.1.1.2, 00:08:30, Serial1/1
[110/20] via 23.1.1.1, 00:08:30, Serial1/0

由于R3-R1的路由可以负载均衡,其余的负载均衡全是不正确的路由

解决方法:
使用route-map进行修改(在重发布的位置进行调用)
可以修改OSPF路由类型(优先级:OE 1 > OE 2)
可以修改metric(默认OE 2类型metric为20)

使用ACL抓取感兴趣流量(2.2.2.2/32与12.1.1.0/24、14.1.1.0/24)

R2(config)#access-list 5 permit 2.2.2.0 0.0.0.255
R2(config)#access-list 5 permit 12.1.1.0 0.0.0.255
R2(config)#access-list 10 permit 14.1.1.0 0.0.0.255

R2(config)#route-map ccie permit 10
R2(config-route-map)#match ip address 5
R2(config-route-map)#set metric 19 (修改ACL 5抓取的流量metric为19)
R2(config)#route-map ccie permit 20
R2(config-route-map)#match ip address 10
R2(config-route-map)#set metric-type type-1 (修改ACL 10抓取的流量类型为OE 1
R2(config-route-map)#exit
R2(config)#route-map ccie permit 30 (空语句,route-map内含拒绝所有)
R2(config-route-map)#exit

调用route-map来修改R3的路由

R2(config)#router ospf 100
R2(config-router)#redistribute rip subnets route-map ccie

完成之后,刷新路由表:

34.0.0.0/24 is subnetted, 1 subnets
C 34.1.1.0 is directly connected, Serial1/1
1.0.0.0/32 is subnetted, 1 subnets
O E2 1.1.1.1 [110/20] via 34.1.1.2, 00:00:04, Serial1/1
[110/20] via 23.1.1.1, 00:00:04, Serial1/0
2.0.0.0/32 is subnetted, 1 subnets
O E2 2.2.2.2 [110/19] via 23.1.1.1, 00:00:04, Serial1/0
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback1
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 34.1.1.2, 00:00:04, Serial1/1
23.0.0.0/24 is subnetted, 1 subnets
C 23.1.1.0 is directly connected, Serial1/0
12.0.0.0/24 is subnetted, 1 subnets
O E2 12.1.1.0 [110/19] via 23.1.1.1, 00:00:05, Serial1/0
14.0.0.0/24 is subnetted, 1 subnets
O E1 14.1.1.0 [110/84] via 23.1.1.1, 00:00:05, Serial1/0

此时R3的路由表全为最优路由

创作者:Eric· Charles


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