15.1 概念
- 一个网络中存在两种不同路由协议,如RIP和OSPF;
- 一个网络中存在两种不同路由进程,如OSPF,同一台路由器两个接口运行两个不同OSPF进程,这是两个进程路由相互独立;
- 如R2路由器两个接口分别运行RIP和OSPF协议,两端完全独立,互不知道;
- 将一种动态路由选择协议信息注入到另一种动态路由选择协议中,从而达到同步全网的信息。
路有重发布是有方向的。
15.2 路由回馈
- 动态路由选择域范围是针对接口的;
- 如将直连网段192.168.1.0注入到RIP中,所有激活RIP的接口上接收。
对于R3和R4,都会学习到RIP的1921.68.1.0的路由,这时在R3上做路由重发布,注入OSPF。
R3将RIP路由注入OSPF,R3想R1更新,即5类LSA,R1同步LSDB,同步给R2,R2同步给R4。但是R3路由器本身就有RIP的该网段路由,同时R3又通过OSPF从R2获取到了该网点的路由。即两种不同的路由协议学习到了去往同一个网络的路由。
R4去往192.168.1.0时,如果比较AD小,则OSPF会更好,这时R4去192.168.1.0会从R2->R1->R3的方向走,绕远路走。
15.3 度量值
15.4 试验
路由器R1配置,配置接口地址和LOOPBACK地址
R1#conf t
R1(config-if)#ip address 192.168.12.1 255.255.255.0
R1(config-if)#no shutdown
R1(config)#interface loopback 0
R1(config-if)#ip address 1.1.1.1 255.255.255.0
R1(config-if)#no shutdown
将接口和LOOPBACK发布到RIP
R1(config)#router rip
R1(config-router)#version 2
R1(config-router)#network 192.168.12.0
R1(config-router)#network 1.1.1.1
路由器R1配置,配置接口地址和LOOPBACK地址
R2#conf t
R2(config)#interface serial 0/0
R2(config-if)#ip address 192.168.12.2 255.255.255.0
R2(config-if)#no shutdown
R2(config)#interface serial 0/1
R2(config-if)#ip address 192.168.23.2 255.255.255.0
R2(config-if)#no shutdown
R2(config)#interface loopback 0
R2(config-if)#ip address 2.2.2.2 255.255.255.0
R2(config-if)#no shutdown
将接口发布到RIP和OSPF
R2(config)#router rip
R2(config-router)#version 2
R2(config-router)#network 192.168.12.0
R2(config)#router ospf 1
R2(config-router)#network 192.168.23.2 0.0.0.0 area 0
路由器R1配置,配置接口地址和LOOPBACK地址
R3#conf t
R3(config)#interface serial 0/1
R3(config-if)#ip address 192.168.23.3 255.255.255.0
R3(config-if)#no shutdown
R3(config)#interface loopback 0
R3(config-if)#ip address 3.3.3.3 255.255.255.0
R3(config-if)#no shutdown
将接口和LOOPBACK发布到OSPF
R3(config)#router ospf 1
R3(config-router)#network 192.168.23.3 0.0.0.0 area 0
R3(config-router)#network 3.3.3.3 0.0.0.0 area 0
R3(config)#interface loopback 0
R3(config-if)#ip ospf network point-to-point
R2能正常学习到RIP和OSPF路由了
R2#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial1/0
R 1.0.0.0/8 [120/1] via 192.168.12.1, 00:00:09, Serial1/0
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
O 3.3.3.0 [110/65] via 192.168.23.3, 00:00:19, Serial1/1
C 192.168.23.0/24 is directly connected, Serial1/1
但是R3并没有学习到任何路由,因为没有重分发,就不会把左右边告诉OSPF进程
R3#show ip route
Codes: 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
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial1/1
R1同样也没有OSPF的路由
R1#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial1/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
这时就需要借助重发布了
15.4.1 重发布RIP路由
首先将RIP注入注入到OSPF中,进入OSPF进程,将RIP重发布,这时可以不设置METRIC值,则默认为20
R2(config)#router ospf 1
R2(config-router)#redistribute rip subnets
路由器多了两条OE2路由,即外部路由
R3#show ip route
Codes: 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
Gateway of last resort is not set
O E2 192.168.12.0/24 [110/20] via 192.168.23.2, 00:00:24, Serial1/1
O E2 1.0.0.0/8 [110/20] via 192.168.23.2, 00:00:24, Serial1/1
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial1/1
由于重发布时单向的,这时对于R1来说,依旧没有变化
R1#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial1/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
15.4.2 重发布OSPF路由
继续在R2上,将OSPF路由注入到RIP中。
R2#conf t
R2(config)#router rip
R2(config-router)#redistribute ospf 1
R1依旧没有,因为向RIP中注入是,如果不设定METRIC值,则视为无穷大,这时充分发失败。
R1#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial1/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
重分发时,加上METRIC值
R2(config)#router rip
R2(config-router)#redistribute ospf 1 metric 2
R1就学到了OSPF路由了
R1#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial0/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
R 3.0.0.0/8 [120/2] via 192.168.12.2, 00:00:05, Serial0/0
R 192.168.23.0/24 [120/2] via 192.168.12.2, 00:00:05, Serial0/0
在R2上配置静态路由,由于METRIC小,会覆盖
R2(config)#ip route 1.0.0.0 255.0.0.0 null 0
R2的路由表中1.0..0.0变成了静态路由
R2#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial0/0
S 1.0.0.0/8 is directly connected, Null0
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
O 3.3.3.0 [110/65] via 192.168.23.3, 00:10:49, Serial0/1
C 192.168.23.0/24 is directly connected, Serial0/1
这时R3中没有了1.0.0.0的路由了,因为没有重发布静态路由。
R3#show ip route
Codes: 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
Gateway of last resort is not set
O E2 192.168.12.0/24 [110/20] via 192.168.23.2, 00:11:20, Serial0/1
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial0/1
去除测试路由
R2(config)#no ip route 1.0.0.0 255.0.0.0 null 0
15.4.3 重发布直连接口
将R3的LOOPBACK地址从OSPF中去除,已重发布的方式注入
R3(config)#router ospf 1
R3(config-router)#no network 3.3.3.3 0.0.0.0 area 0
这时R2中就没有3.3.3.3的路由了
R2#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial0/0
S 1.0.0.0/8 is directly connected, Null0
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial0/1
在R3上重分发本地所有直连接口,要求物理和协议上都是UP状态。
R3(config)#router ospf 1
R3(config-router)#redistribute connected subnets metric 10 metric-type 1
这时R2上就有了3.3.3.3的路由
R2#show ip route
Codes: 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
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, Serial0/0
S 1.0.0.0/8 is directly connected, Null0
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
O E1 3.3.3.0 [110/74] via 192.168.23.3, 00:00:07, Serial0/1
C 192.168.23.0/24 is directly connected, Serial0/1
15.4.4 重分发静态路由
在R1上去除RIP
R1(config)#no router rip
在R2上去除RIP
R2(config)#no router rip
这时R3中就不会有去往1.1.1.1的路由了
R2上配置静态路由
R2(config)#ip route 1.1.1.0 255.255.255.0 192.168.12.1
重发布静态路由
R2(config)#router ospf 1
R2(config-router)#redistribute static subnets
R3就有1.1.1.1的路由了
R3#show ip route
Codes: 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
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
O E2 1.1.1.0 [110/20] via 192.168.23.2, 00:00:13, Serial0/1
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial0/1
15.5 重分发模型
15.5.1 单点单向重分发
引发次优路由的问题
15.5.2 单点双向重发布
如试验的R2路由器,两边重发布
15.5.3 多点重发布
边界同时做重发布,R3和R4都做重发布。
R3上重发布后,如果在R4重发布,容易引发失败,因为R3重发布后,R4已经有了,R4再重发布,相当于重发布已经存在的,所以失败。
15.5.4 多点双向重发布
R2和R3朝两个方向都重发布;
15.6 配置
需要先进入路由选择进程。然后选择该进程下需要做重发布的路由。
15.6.1 重分发RIP
.
如需要重发布到RIP,进入RIP进程,然后选择需要将重分发的协议。
需要设置METRIC,否则会失败。
需要配置METRIC,默认默认无穷大。
15.6.2 重分发OSPF
这个可以不需要METRIC,用默认值,但是需要加subnets,否则只能发布主类路由。
15.6.3 重分发EIGRP
需要完整的指定5个元素