路由引入造成环路

1、. .背景需求：在现实中，有可能在网络中同时运行了多种路由协议，同时到达网络物理层存在备份效果，甚至采用多边界的方法。在多协议、多边界设备网络环境下，需要进展路由协议间的引入和策略，才能实现全网通信、环路杜绝。6.2.2 拓扑图、需求：要求如图配置，使得全网互通在R2上ospf引入rip，R5上rip引入ospf。同时保证当R1上192路由down时，网络不能存在环路提示：使用tag标记 + 路由策略实现沈相宇r1:interface LoopBack0ip address 00 55interface GigabitEthernet0/1/1p

2、ort link-mode routeip address interface GigabitEthernet0/1/2port link-mode routeip address ospf 1area network 00 network 55network 55r2:interface GigabitEthernet0/1/0ip address

3、interface GigabitEthernet0/1/1ip address ospf 1import-route directimport-route rip 1 cost 20 tag 20area network 55rip 1undo summaryversion 2network r3:interface GigabitEthernet0/1/0ip address interface GigabitEthernet0/1/2ip

4、address rip 1undo summaryversion 2network network r5:interface GigabitEthernet0/1/0ip address interface GigabitEthernet0/1/2ip address ospf 1area network 55rip 1undo summaryversion 2network 35.0.

5、0.0import-route directimport-route ospf 1 route-policy qweroute-policy qwe deny node 10if-match tag 20route-policy qwe permit node 20齐海涛R1配置#ospf 1area network 00 network 55network 55R2配置#ospf 1import-route rip 1 route-policy lxsbarea n

6、etwork 55#rip 1undo summaryversion 2network #route-policy lxsb deny node 1if-match tag 20route-policy lxsb permit node 2R3配置#rip 1undo summaryversion 2network network R5配置#ospf 1area network 55#rip 1undo summaryversion 2network i

7、mport-route ospf 1 tag 20192路由没有down掉R3路由表r3dis ip rouRouting Tables: PublicDestinations : 8Routes : 8Destination/Mask ProtoPreCostNextHopInterface/24RIP 100GE0/1//24Direct 0 0GE0/1/0/32Direct 0 0 InLoop0/24Direct 0 0GE0/1//

8、32Direct 0 0 InLoop0/8Direct 0 0 InLoop0/32Direct 0 0 InLoop000/32 RIP 100GE0/1/2192路由down掉R3路由表r3dis ip rouRouting Tables: PublicDestinations : 7Routes : 7Destination/Mask ProtoPreCostNextHopInterface/24RIP 100GE0/1/2

9、/24Direct 0 0GE0/1/0/32Direct 0 0 InLoop0/24Direct 0 0GE0/1//32Direct 0 0 InLoop0/8Direct 0 0 InLoop0/32Direct 0 0 InLoop0各路由配置如下：R1interface LoopBack1ip address 00 55#inter

10、face GigabitEthernet0/1/1ip address #          interface GigabitEthernet0/1/2ip address #ospf 1area   network 00   network 55  network

11、 55R2interface GigabitEthernet0/1/0ip address #interface GigabitEthernet0/1/1ip address #ospf 1import-route directimport-route rip 1 tag 9area   network 55#rip 1undo summaryversion 2network #R3#interf

12、ace GigabitEthernet0/1/0ip address #interface GigabitEthernet0/1/2ip address #rip 1        undo summaryversion 2network network R5#interface GigabitEthernet0/1/0ip address #inter

13、face GigabitEthernet0/1/2ip address #ospf 1area   network 55#rip 1  undo summaryversion 2      network import-route direct route-policy filtero2rimport-route ospf 1 route-policy filtero2r#route-pol

14、icy filtero2r deny node 5if-match tag 9route-policy filtero2r permit node 10此时R1上loopback正常，查看路由表R1 R3 此时R1上loopback接口shutdown，各路由器上该条路由消失R1 R3R5路由表.JPG(45.26 KB, 下载次数: 0)R3n.JPG(35.12 KB, 下载次数: 0)李鑫R1interface GigabitEthernet0/1/1ip address interface GigabitEther

15、net0/1/2ip address ospf 1 router-id area network 00 network 55network 55R2为OSPF引入的RIP路由打上Tag标签为5.interface GigabitEthernet0/1/0ip address interface GigabitEthernet0/1/1ip address 255.255

16、.255.0ospf 1 router-id import-route directimport-route rip 1 cost 2 type 1tag 5area network 55rip 1undo summaryversion 2network R3interface GigabitEthernet0/1/0ip address interface GigabitEthernet0/1/2ip address rip 1un

17、do summaryversion 2network network R5在R5上做路由策略，过滤Tag标签为5的路由。interface GigabitEthernet0/1/0ip address interface GigabitEthernet0/1/2ip address ospf 1 router-id area network 55rip 1undo summaryversion 2network 35.0

18、.0.0import-route directimport-route ospf 1 route-policyotrroute-policy otr deny node 10if-match tag 5route-policy otr permit node 20DOWN掉R1的192网段，检查R3路由表，无此路由解决环路。r3dis ip rouRouting Tables: Public Destinations : 8Routes : 8Destination/Mask Proto PreCostNextHopInterface/24RIP 100 GE

19、0/1//24RIP 100 GE0/1//24Direct 0 0GE0/1/0/32Direct 0 0 InLoop0/24Direct 0 0GE0/1//32Direct 0 0 InLoop0/8Direct 0 0 InLoop0/32Direct 0 0 InLoop0多进程OSPF发布LSA形成路由环路的躲避方法2021-10-20 2

20、2:29小大来源:.ming4.转发至：1. 【问题】上图中，GSYYB_WN_DS01和GSYYB_WN_DS02为锐捷两台交换机，GS1_WN_DS01和GS1_WN_DS02为H3CS8512交换机。为实现省行数据中心与营业部和同城网点间的网络互通，在OSPF100和OSPF 1间进展了路由的相互引入，具体为将OSPF 100内的路由引入到OSPF1中，在营业部两台核心交换机GSYYB_WN_DS01和GSYYB_WN_DS02上针对营业部的生产和办公配置了一样的会聚静态路由，在同城路由器上配置了到网点的会聚静态路由，并且将该路由引入到OSPF1中(类型为TYPE 2，GSYYB_WN_

21、DS01上注入时设置COST 为20，GSYYB_WN_DS02上注入时设置COST 为100，同城路由器上注入时设置COST为20)，然后在GS1_WN_DS01和GS1_WN_DS02上将该路由重分发到OSPF 100中。当将省行GS_WN_DS01和营业部GSYYB_WN_DS01间的线路DOWN掉，此时到营业部无法正常省行数据中心。2. 【问题原因】通过在GS1_WN_DS01和GS1_WN_DS02上查看到营业部的路由发现，在GS1_WN_DS01和GS1_WN_DS02上形成了如下路由环路，从而导致营业部无法正常省行数据中心。dis ip routing-table 10.154.

22、32.18Destination/Mask Protocol Pre Cost Nexthop Interface/23 O_ASE 190 20 78 Vlan-interface819dis ip routing-table 8Destination/Mask Protocol Pre Cost Nexthop Interface/23 O_ASE 190 100 Vlan-interface8013. 【问题分析】根据演练前保存的S8512的路由表信息，在GS1_WN_DS

23、01和GS1_WN_DS02查看到营业部的一条路由信息如下：dis ip routing-table 8/23 O_ASE 190 20 42 Vlan-interface881dis ip routing-table 8/23 O_ASE 190 100 Vlan-interface801此时营业部的业务是正常的，但此时S8512上路由已经与规划的不一致，根据规划在GS1_WN_DS01和GS1_WN_DS02查看到营业部的一条路由信息应该如下：dis i

24、p routing-table 8/23 O_ASE 190 20 42 Vlan-interface881dis ip routing-table 8/23 O_ASE 190 20 Vlan-interface882当将省行GS_WN_DS01和营业部GSYYB_WN_DS01间的线路DOWN掉，此时在GS1_WN_DS01和GS1_WN_DS02查看在营业部交换机上引入到OSPF1中的路由信息如下：dis ip routing-table 10.154

25、.32.18Destination/Mask Protocol Pre Cost Nexthop Interface/23 O_ASE 190 20 78 Vlan-interface819dis ip routing-table 8Destination/Mask Protocol Pre Cost Nexthop Interface/23 O_ASE 190 100 Vlan-interface801此时在GS_WN_DS01和GS_WN_DS01间出现了路由环路，从而导致营业部无法正常省行数据中心，出现上述异常现象的原因如下：1、由于口字型组网和ospf路由的引入，导致在2台85上对于GSYYB_WN_DS01在ospf 1中引入的静态路由在2个ospf进程(OSPF 1 和 OSPF 100)中都可以学到。举例如下：对于GSYYB_WN_DS01的静态路由：/23 ，引入到ospf 1中，那么GS1_WN_DS01在ospf 1中学习到了该路由，因在GS1_WN_DS01上将ospf 1 引入到os