多点双向重分布后次优路径的解决方法 推荐

概念预习:

什么是多点双向路由重发布?

不同路由协议相互之间通过重发布相互传递各自的路由信息,承担重发布工作ASBR路由器数量多于一台.ASBR在每个路由协议内都能够收到相互间重发布通告的路由信息。

一:实验拓扑:





二:实验目的:

双点:为了路由条目的冗余,Down掉任何一台ASBR路由器都不影响两个AS的通信;

双向:不同AS的路由能够相互学习。

三:实验描述:

R1,R2,R3运行OSPF,并将1.1.1.1重分布进OSPF[redistribute connected subnet]

R2,R3,R4运行EIGRP,并将4.4.4.4重分布进EIGRP[redistribute connected subnet]

四:实验要求:

R1能够学到EIGRP的路由,并且到4.4.4.4是负载均衡

R4能够学到OSPF的路由,并且到1.1.1.1是负载均衡

五:实验过程:

1:基本接口的配置:

R1(config)#int s0/1

R1(config-if)#ip add 12.0.0.1 255.255.255.0

R1(config-if)#no sh

R1(config-if)#int s0/2

R1(config-if)#ip add 13.0.0.1 255.255.255.0

R1(config-if)#no sh

R1(config-if)#int lo 0

R1(config-if)#ip add 1.1.1.1 255.255.255.0

R2(config)#int s0/1

R2(config-if)#ip add 12.0.0.2 255.255.255.0

R2(config-if)#no sh

R2(config-if)#int e1/0

R2(config-if)#ip add 10.0.234.2 255.255.255.0

R2(config-if)#no sh

R2(config-if)#int lo 0

R2(config-if)#ip add 2.2.2.2 255.255.255.0

R2(config-if)#^Z

R3(config)#int s0/2

R3(config-if)#ip add 13.0.0.3 255.255.255.0

R3(config-if)#no sh

R3(config-if)#int e1/0

R3(config-if)#ip add 10.0.234.3 255.255.255.0

R3(config-if)#no sh

R3(config-if)#int lo 0

R3(config-if)#ip add 3.3.3.3 255.255.255.0

R4(config)#int e0/0

R4(config-if)#ip add 10.0.234.4 255.255.255.0

R4(config-if)#no sh

R4(config-if)#int lo 0

R4(config-if)#ip add 4.4.4.4 255.255.255.0

R4(config-if)#no sh

2:路由的配置:

R1(config)#router os 1

R1(config-router)#net 12.0.0.0 0.0.0.255 a 0

R1(config-router)#net 13.0.0.0 0.0.0.255 a 0

R1(config-router)#redistribute connected subnets

R2(config)#router os 1

R2(config-router)#net 12.0.0.0 0.0.0.255 a 0

R2(config-router)#net 2.2.2.0 0.0.0.255 a 0

R2(config-router)#exit

R2(config)#router eigrp 1

R2(config-router)#net 10.0.234.0 0.0.0.255

R2(config-router)#no au

R3(config)#router os 1

R3(config-router)#net 13.0.0.0 0.0.0.255 a 0

R3(config-router)#net 3.3.3.0 0.0.0.255 a 0

R3(config-router)#exit

R3(config)#router eigrp 1

R3(config-router)#net 10.0.234.0 0.0.0.255

R3(config-router)#no au

R4(config)#router eigrp 1

R4(config-router)#net 10.0.234.0 0.0.0.255

R4(config-router)#redistribute connected

R1#sho ip route

1.0.0.0/24 is subnetted, 1 subnets

C 1.1.1.0 is directly connected, Loopback0

2.0.0.0/32 is subnetted, 1 subnets

O 2.2.2.2 [110/65] via 12.0.0.2, 00:01:58, Serial0/1

3.0.0.0/32 is subnetted, 1 subnets

O 3.3.3.3 [110/65] via 13.0.0.3, 00:01:58, Serial0/2

12.0.0.0/24 is subnetted, 1 subnets

C 12.0.0.0 is directly connected, Serial0/1

13.0.0.0/24 is subnetted, 1 subnets

C 13.0.0.0 is directly connected, Serial0/2

R4#sho ip route

4.0.0.0/24 is subnetted, 1 subnets

C 4.4.4.0 is directly connected, Loopback0

10.0.0.0/24 is subnetted, 1 subnets

C 10.0.234.0 is directly connected, Ethernet0/0

//发现R1和R4不能相互学习路由,下来我们在E2和R3上实现双向重分布。

3:双向重分布的配置:

R2(config)#router os 1

R2(config-router)#redistribute eigrp 1 subnets

R2(config-router)#exit

R2(config)#router eigrp 1

R2(config-router)#redistribute ospf 1 metric 100000 1 255 1 1500

R3(config)#router os 1

R3(config-router)#redistribute eigrp 1 subnets

R3(config-router)#router eigrp 1

R3(config-router)#redistribute ospf 1 metric 100000 1 255 1 1500

R4#sho ip route eigrp

1.0.0.0/24 is subnetted, 1 subnets

D EX 1.1.1.0 [170/281856] via 10.0.234.3, 00:04:57, Ethernet0/0

[170/281856] via 10.0.234.2, 00:04:57, Ethernet0/0

2.0.0.0/24 is subnetted, 1 subnets

D 2.2.2.0 [90/409600] via 10.0.234.2, 00:06:15, Ethernet0/0

3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/409600] via 10.0.234.3, 00:06:15, Ethernet0/0

12.0.0.0/24 is subnetted, 1 subnets

D EX 12.0.0.0 [170/281856] via 10.0.234.3, 00:04:57, Ethernet0/0

[170/281856] via 10.0.234.2, 00:04:57, Ethernet0/0

13.0.0.0/24 is subnetted, 1 subnets

D EX 13.0.0.0 [170/281856] via 10.0.234.3, 00:04:57, Ethernet0/0

[170/281856] via 10.0.234.2, 00:04:57, Ethernet0/0

//发现R4上有到达R1的负载均衡的路由。

R1#sho ip route

1.0.0.0/24 is subnetted, 1 subnets

C 1.1.1.0 is directly connected, Loopback0

2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

O 2.2.2.2/32 [110/65] via 12.0.0.2, 00:01:34, Serial0/1

O E2 2.2.2.0/24 [110/20] via 13.0.0.3, 00:01:34, Serial0/2

3.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

O 3.3.3.3/32 [110/65] via 13.0.0.3, 00:01:34, Serial0/2

O E2 3.3.3.0/24 [110/20] via 12.0.0.2, 00:01:34, Serial0/1

4.0.0.0/24 is subnetted, 1 subnets

O E2 4.4.4.0 [110/20] via 12.0.0.2, 00:01:33, Serial0/1

10.0.0.0/24 is subnetted, 1 subnets

O E2 10.0.234.0 [110/20] via 13.0.0.3, 00:01:34, Serial0/2

[110/20] via 12.0.0.2, 00:01:34, Serial0/1

12.0.0.0/24 is subnetted, 1 subnets

C 12.0.0.0 is directly connected, Serial0/1

13.0.0.0/24 is subnetted, 1 subnets

C 13.0.0.0 is directly connected, Serial0/2

//发现R1上没有到4.4.4.0的负载均衡的路由,Why?

我们查看一下两台ASBR路由器上的路由表:

R3#sho ip route

1.0.0.0/24 is subnetted, 1 subnets

O E2 1.1.1.0 [110/20] via 13.0.0.1, 00:02:47, Serial0/2

2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

O 2.2.2.2/32 [110/129] via 13.0.0.1, 00:02:47, Serial0/2

D EX 2.2.2.0/24 [170/281856] via 10.0.234.2, 00:08:55, Ethernet1/0

3.0.0.0/24 is subnetted, 1 subnets

C 3.3.3.0 is directly connected, Loopback0

4.0.0.0/24 is subnetted, 1 subnets

O E2 4.4.4.0 [110/20] via 13.0.0.1, 00:02:47, Serial0/2

10.0.0.0/24 is subnetted, 1 subnets

C 10.0.234.0 is directly connected, Ethernet1/0

12.0.0.0/24 is subnetted, 1 subnets

O 12.0.0.0 [110/128] via 13.0.0.1, 00:02:47, Serial0/2

13.0.0.0/24 is subnetted, 1 subnets

C 13.0.0.0 is directly connected, Serial0/2

发现R3上没有4.4.4.4的EIGRP路由，取而代之的是OSPF路由,按理来说应该通过EIGRP好,但现在选的是OSPF,原因是R3从EIGRP学到的4.4.4.0的路由是外部路由,管理距离为170,R3从R2（将EIGRP重分布过来的）OSPF学过来的到达4.4.4.0的路由管理距离为110,R3取管理距离小的放入它的路由表,从而导致R3将EIGRP重分布到OSPF时本地EIGRP表没有4.4.4.0的路由,因此R1上没有到达4.4.4.0的负载均衡的路由。

解决方法:修改AD

将R2从R3上学习到的OSPF路由的管理距离改的比外部EIGRP(170)的管理距离还高,

将R3从R2上学到的EIGRP的路由的管理距离改的比外部EIGRP的管理距离还高即可解决。

R2(config)#router ospf 1

R2(config-router)#distance 180 3.3.3.3 0.0.0.0

//R2从3.3.3.3学过来的OSPF的路由修改管理距离为180

R3(config)#router os 1

R3(config-router)#distance 180 2.2.2.2 0.0.0.0

//R3从2.2.2.2学过来的路由修改管理距离为180

查看R2和R3上的路由表:

R2#sho ip route

1.0.0.0/24 is subnetted, 1 subnets

O E2 1.1.1.0 [110/20] via 12.0.0.1, 00:00:58, Serial0/1

2.0.0.0/24 is subnetted, 1 subnets

C 2.2.2.0 is directly connected, Loopback0

3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/409600] via 10.0.234.3, 00:16:50, Ethernet1/0

4.0.0.0/24 is subnetted, 1 subnets

D EX 4.4.4.0 [170/281856] via 10.0.234.4, 00:00:35, Ethernet1/0

10.0.0.0/24 is subnetted, 1 subnets

C 10.0.234.0 is directly connected, Ethernet1/0

12.0.0.0/24 is subnetted, 1 subnets

C 12.0.0.0 is directly connected, Serial0/1

13.0.0.0/24 is subnetted, 1 subnets

O 13.0.0.0 [110/128] via 12.0.0.1, 00:00:59, Serial0/1

R3#sho ip route

1.0.0.0/24 is subnetted, 1 subnets

O E2 1.1.1.0 [110/20] via 13.0.0.1, 00:01:21, Serial0/2

2.0.0.0/24 is subnetted, 1 subnets

D 2.2.2.0 [90/409600] via 10.0.234.2, 00:13:37, Ethernet1/0

3.0.0.0/24 is subnetted, 1 subnets

C 3.3.3.0 is directly connected, Loopback0

4.0.0.0/24 is subnetted, 1 subnets

D EX 4.4.4.0 [170/281856] via 10.0.234.4, 00:01:20, Ethernet1/0

10.0.0.0/24 is subnetted, 1 subnets

C 10.0.234.0 is directly connected, Ethernet1/0

12.0.0.0/24 is subnetted, 1 subnets

O 12.0.0.0 [110/128] via 13.0.0.1, 00:01:21, Serial0/2

13.0.0.0/24 is subnetted, 1 subnets

C 13.0.0.0 is directly connected, Serial0/2

//发现两台ABR上已经解决了次优路由的问题,再看R1和R4的负载均衡问题。

R1#sho ip route ospf

2.0.0.0/24 is subnetted, 1 subnets

O E2 2.2.2.0 [110/20] via 13.0.0.3, 00:17:02, Serial0/2

[110/20] via 12.0.0.2, 00:17:02, Serial0/1

3.0.0.0/24 is subnetted, 1 subnets

O E2 3.3.3.0 [110/20] via 13.0.0.3, 00:17:02, Serial0/2

[110/20] via 12.0.0.2, 00:17:02, Serial0/1

4.0.0.0/24 is subnetted, 1 subnets

O E2 4.4.4.0 [110/20] via 13.0.0.3, 00:02:29, Serial0/2

[110/20] via 12.0.0.2, 00:02:29, Serial0/1

10.0.0.0/24 is subnetted, 1 subnets

O E2 10.0.234.0 [110/20] via 13.0.0.3, 00:17:02, Serial0/2

[110/20] via 12.0.0.2, 00:17:02, Serial0/1

R4#sho ip route eigrp

1.0.0.0/24 is subnetted, 1 subnets

D EX 1.1.1.0 [170/281856] via 10.0.234.3, 00:02:42, Ethernet0/0

[170/281856] via 10.0.234.2, 00:02:42, Ethernet0/0

2.0.0.0/24 is subnetted, 1 subnets

D 2.2.2.0 [90/409600] via 10.0.234.2, 00:18:45, Ethernet0/0

3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/409600] via 10.0.234.3, 00:18:45, Ethernet0/0

12.0.0.0/24 is subnetted, 1 subnets

D EX 12.0.0.0 [170/281856] via 10.0.234.3, 00:02:42, Ethernet0/0

[170/281856] via 10.0.234.2, 00:02:42, Ethernet0/0

13.0.0.0/24 is subnetted, 1 subnets

D EX 13.0.0.0 [170/281856] via 10.0.234.3, 00:03:05, Ethernet0/0

[170/281856] via 10.0.234.2, 00:03:05, Ethernet0/0

//发现已经实现了负载均衡。