交换路由CCIE之路――路由策略

1、 实验 路由策略一实验拓扑图1 实验一 实验要求：原本网络使用EIGRP现在要求用OSPF来发现网络拓扑。实验分析：要是网络平滑过渡可先将OSPF配置好，然后理由改变EIGRP的管理距离使OSPF替换EIGRP进路由表，等到全网为OSPF后，去掉EIGRP.实验操作及结果：首先全网为EIGRP如下r1#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsD 192.16

2、8.23.0 90/ via 192.168.12.2, 00:01:48, Serial0/0C 192.168.1.0/24 is directly connected, Ethernet3/0D 192.168.3.0/24 90/ via 192.168.12.2, 00:00:13, Serial0/0r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.23.0/30 is subnetted, 1 subnets

3、C 192.168.23.0 is directly connected, Serial0/2D 192.168.1.0/24 90/ via 192.168.12.1, 00:02:56, Serial0/0D 192.168.3.0/24 90/ via 192.168.23.2, 00:01:16, Serial0/2r3#show ip route 192.168.12.0/30 is subnetted, 1 subnetsD 192.168.12.0 90/ via 192.168.23.1, 00:01:21, Serial0/0 192.168.23.0/30 is subne

4、tted, 1 subnetsC 192.168.23.0 is directly connected, Serial0/0D 192.168.1.0/24 90/ via 192.168.23.1, 00:01:21, Serial0/0C 192.168.3.0/24 is directly connected, Ethernet3/0现在在每个路由器都配置OSPF能发现都建立邻居，但没进路由表r1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface192.168.23.1 0 FULL/ - 00

5、:00:32 192.168.12.2 Serial0/0r2#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface192.168.23.2 0 FULL/ - 00:00:35 192.168.23.2 Serial0/2192.168.12.1 0 FULL/ - 00:00:31 192.168.12.1 Serial0/0r3#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface192.168.23.1 0

6、FULL/ - 00:00:32 192.168.23.1 Serial0/0r1#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsD 192.168.23.0 90/ via 192.168.12.2, 00:01:48, Serial0/0C 192.168.1.0/24 is directly connected, Ethernet3/0D 192.168.3

7、.0/24 90/ via 192.168.12.2, 00:00:13, Serial0/0r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is directly connected, Serial0/2D 192.168.1.0/24 90/ via 192.168.12.1, 00:02:56, Serial0/0D 192

8、.168.3.0/24 90/ via 192.168.23.2, 00:01:16, Serial0/2r3#show ip route 192.168.12.0/30 is subnetted, 1 subnetsD 192.168.12.0 90/ via 192.168.23.1, 00:01:21, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is directly connected, Serial0/0D 192.168.1.0/24 90/ via 192.168.23.1, 00:01:21,

9、 Serial0/0C 192.168.3.0/24 is directly connected, Ethernet3/0主要原因是OSPF管理距离比EIGRP大，所以没有进入路由表，这时候将EIGRP的管理距离加大到120，这时候路由表就发生改变了，但EIGRP邻居依然存在r1(config)#router eigrp 10r1(config-router)#distance eigrp 120 170 /将eigrp内部管理距离改为120110r1(config-router)#exitr2(config)#router eigrp 10r2(config-router)#distance

10、 eigrp 120 170r3(config)#router eigrp 10r3(config-router)#distance eigrp 120 170r3(config-router)#exit重新查看路由表，发现OSPF进了路由表r1#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsO 192.168.23.0 110/128 via 192.168.1

11、2.2, 00:03:18, Serial0/0C 192.168.1.0/24 is directly connected, Ethernet3/0O 192.168.3.0/24 110/138 via 192.168.12.2, 00:03:18, Serial0/0r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is di

12、rectly connected, Serial0/2O 192.168.1.0/24 110/74 via 192.168.12.1, 00:02:00, Serial0/0O 192.168.3.0/24 110/74 via 192.168.23.2, 00:02:00, Serial0/2r3#show ip route 192.168.12.0/30 is subnetted, 1 subnetsO 192.168.12.0 110/128 via 192.168.23.1, 00:01:48, Serial0/0 192.168.23.0/30 is subnetted, 1 su

13、bnetsC 192.168.23.0 is directly connected, Serial0/0O 192.168.1.0/24 110/138 via 192.168.23.1, 00:02:05, Serial0/0C 192.168.3.0/24 is directly connected, Ethernet3/0EIGRP邻居依然存在，说明该进程依旧在运行r1#show ip eigrp neighbors IP-EIGRP neighbors for process 10H Address Interface Hold Uptime SRTT RTO Q Seq (sec)

14、(ms) Cnt Num0 192.168.12.2 Se0/0 12 00:01:16 114 684 0 17 r2#show ip eigrp neighbors IP-EIGRP neighbors for process 10H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num0 192.168.23.2 Se0/2 10 00:00:59 1553 5000 0 101 192.168.12.1 Se0/0 12 00:01:12 144 864 0 8r3#show ip eigrp neighbors

15、 IP-EIGRP neighbors for process 10H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num0 192.168.23.1 Se0/0 12 00:00:48 120 720 0 19这时候实现了路由的平滑过渡，可以删掉EIGRP了。实验二实验要求：将172.16.0.0/16所有网段宣告进OSPF 但希望R3学不到172.16.4.0/24这条路由实验分析： 可利用ACL直接将该路由在R3上拒绝，因为是链路状态协议故只能在本路由器IN方向拒绝，它拒绝的是路由而不是LSA，因此必须这样做。实

16、验操作及结果：在没有采取任何措施时，将所有网段全部发布进OSPF R3路由表如下r3#show ip route 192.168.12.0/30 is subnetted, 1 subnetsO 192.168.12.0 110/128 via 192.168.23.1, 00:00:06, Serial0/0 172.16.0.0/32 is subnetted, 5 subnetsO 172.16.4.0 110/129 via 192.168.23.1, 00:00:06, Serial0/0O 172.16.5.0 110/129 via 192.168.23.1, 00:00:06,

17、 Serial0/0O 172.16.1.0 110/129 via 192.168.23.1, 00:00:06, Serial0/0O 172.16.2.0 110/129 via 192.168.23.1, 00:00:06, Serial0/0O 172.16.3.0 110/129 via 192.168.23.1, 00:00:06, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is directly connected, Serial0/0O 192.168.1.0/24 110/138 via

18、192.168.23.1, 00:00:06, Serial0/0C 192.168.3.0/24 is directly connected, Ethernet3/0这时候在R3上拒绝4.0网段进路由表，只能在R3进接口上拒绝它，因为所能拒绝的是路由，LSA还是能过来的，R3通过LSA能产生4.0的路由，但因为接口采用了分发列表控制了这条路由的进入，因此它进不了路由表。结果如下r3(config)#access-list 10 deny host 172.16.1.0 r3(config)#access-list 10 permit any r3(config)#router ospf 1r

19、3(config-router)#distribute-list 10 in s0/0 /拒绝了的所有的172.16.1.0这时候查路由表不会有1.0网段了r3#show ip route 192.168.12.0/30 is subnetted, 1 subnetsO 192.168.12.0 110/128 via 192.168.23.1, 00:00:04, Serial0/0 172.16.0.0/32 is subnetted, 4 subnetsO 172.16.4.0 110/129 via 192.168.23.1, 00:00:04, Serial0/0O 172.16.5

20、.0 110/129 via 192.168.23.1, 00:00:04, Serial0/0O 172.16.2.0 110/129 via 192.168.23.1, 00:00:04, Serial0/0O 172.16.3.0 110/129 via 192.168.23.1, 00:00:04, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is directly connected, Serial0/0O 192.168.1.0/24 110/138 via 192.168.23.1, 00:00:

21、04, Serial0/0C 192.168.3.0/24 is directly connected, Ethernet3/0实验三实验要求：将172.16.0.0/16所有网段宣告为RIP并重发布进来，但172.16.4.0/24不能宣告进OSPF实验分析：一可以直接在边界拒绝掉该网段进入，二可以采用route-map进行匹配从而拒绝。由于重发布汇总会产生一条反馈路由，这时也要拒绝掉。实验操作及结果：在ASBR重发布RIP进OSPF时将4.0网段直接拒绝发布， 如下r1(config)#access-list 10 deny 172.16.4.0 r1(config)#access-lis

22、t 10 permit anyr1(config)#router ospf 1r1(config-router)#distribute-list 10 out rip /拒绝4.0从RIP出来r1(config-router)#redistribute rip subnetsr2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 172.16.0.0/32 is subnetted, 4 subnetsO E2 172.16.5.0 110/2

23、0 via 192.168.12.1, 00:00:03, Serial0/0O E2 172.16.1.0 110/20 via 192.168.12.1, 00:00:03, Serial0/0O E2 172.16.2.0 110/20 via 192.168.12.1, 00:00:03, Serial0/0O E2 172.16.3.0 110/20 via 192.168.12.1, 00:00:03, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is directly connected, Ser

24、ial0/2O 192.168.1.0/24 110/74 via 192.168.12.1, 00:00:03, Serial0/0O 192.168.3.0/24 110/74 via 192.168.23.2, 00:00:03, Serial0/2第二种方法在重发布中用route-map进行匹配发布 也能得到想要的结果r1(config)#access-list 10 deny 172.16.4.0 /此处deny为不匹配 r1(config)#access-list 10 permit anyr1(config)#route-map fuckjiuge permit 10 r1(co

25、nfig-route-map)#match ip ad 10 r1(config-route-map)#exitr1(config)#router ospf 1r1(config-router)#redistribute rip subnets route-map fuckjiuge /匹配相应的route-map信息r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 172.16.0.0/32 is subnetted, 4 subnet

26、sO E2 172.16.5.0 110/20 via 192.168.12.1, 00:06:35, Serial0/0O E2 172.16.1.0 110/20 via 192.168.12.1, 00:06:35, Serial0/0O E2 172.16.2.0 110/20 via 192.168.12.1, 00:06:35, Serial0/0O E2 172.16.3.0 110/20 via 192.168.12.1, 00:06:35, Serial0/0 192.168.23.0/30 is subnetted, 1 subnetsC 192.168.23.0 is d

27、irectly connected, Serial0/2O 192.168.1.0/24 110/74 via 192.168.12.1, 00:06:35, Serial0/0O 192.168.3.0/24 110/74 via 192.168.23.2, 00:06:35, Serial0/2关于反馈路由问题r2(config)#router ospf 1r2(config-router)#summary-address 172.16.0.0 255.255.0.0 /在边界将网段进行汇总这时候ASBR会产生一条汇总信息r2#show ip route 192.168.12.0/30 i

28、s subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masksO 172.16.0.0/16 is a summary, 00:00:14, Null0R 172.16.1.0/24 120/1 via 192.168.12.1, 00:00:17, Serial0/0R 172.16.2.0/24 120/1 via 192.168.12.1, 00:00:17, Serial0/0 192.168.23.

29、0/30 is subnetted, 1 subnetsC 192.168.23.0 is directly connected, Serial0/2在将OSPF重发布进RIP时，汇总信息会重发布进来，从而形成了反馈路由r1#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masksR 172.16.0.0/16 120/5 via 192.1

30、68.12.2, 00:00:20, Serial0/0 /反馈路由C 172.16.1.0/24 is directly connected, Ethernet3/0C 172.16.2.0/24 is directly connected, Ethernet3/1 192.168.23.0/30 is subnetted, 1 subnetsR 192.168.23.0 120/5 via 192.168.12.2, 00:00:24, Serial0/0为了避免反馈路由，可以拒绝汇总的重发布出去r2(config)#access-list 10 deny host 172.16.0.0

31、r2(config)#access-list 10 permit anyr2(config)#router ripr2(config-router)#distribute-list 10 out ospf 1r1#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 172.16.0.0/24 is subnetted, 2 subnetsC 172.16.1.0 is directly connected, Ethernet3/0C 172.16

32、.2.0 is directly connected, Ethernet3/1 192.168.23.0/30 is subnetted, 1 subnetsR 192.168.23.0 120/5 via 192.168.12.2, 00:00:01, Serial0/0 当然也可以通过route-map进行匹配然后重发布出去实验四实验要求：R2 R3执行双向重发布，R1不希望收到R4的RIP信息，R4不希望收到R1的RIP信息实验分析：可以在边界上先标记发布进来的路由，然后到另一边用route-map过滤掉。由于路由条目过多所用标记的方法能简化配置。实验操作及结果：将RIP发布进路由表时打

33、上标识r2(config)#router ospf 1r2(config-router)#redistribute rip subnets tag 50在另一个边界上用route-map把匹配有标识的过滤掉就可以阻止其发布了r3(config)#route-map fuckjiuge deny 10r3(config-route-map)#match tag 50 /拒绝的动作时标记为50的r3(config-route-map)#exit r3(config)#route-map fuckjiuge permit 20 /由于route-map也有默认拒绝所有，所以这一条要加上r3(conf

34、ig-route-map)#exitr3(config)#router ripr3(config-router)#redistribute ospf 1 metric 5 route-map fuckjiuger4#show ip route 172.1.0.0/32 is subnetted, 5 subnetsC 172.1.5.0 is directly connected, Loopback4C 172.1.4.0 is directly connected, Loopback3C 172.1.1.0 is directly connected, Loopback0C 172.1.3.

35、0 is directly connected, Loopback2C 172.1.2.0 is directly connected, Loopback1 192.168.23.0/30 is subnetted, 1 subnetsR 192.168.23.0 120/5 via 192.168.34.1, 00:00:03, Serial0/1 192.168.34.0/30 is subnetted, 1 subnetsC 192.168.34.0 is directly connected, Serial0/1R 192.168.3.0/24 120/5 via 192.168.34

36、.1, 00:00:03, Serial0/1这时候就不会有关于172.16.0.0的相关信息了。实验五实验拓扑 实验要求：实验过程中先重发布R2,在发布R3,分析R2 R3 R4关于RIP发布过来的路由，并分析次佳路由产生的原因，及解决方法。实验分析：首先分析没进行重发布时R2 R3 关于RIP的路由 ，这时候由于没有外部路由影响应该都有各自的RIP信息。当R2进行重发布后路由 R3会收到10.10.1.0及12.0/3013.0/30的5类OSPF信息，通过与自己的路由比较，发现关于RIP 的信息由于管理距离大于OSPF因此会被取代，因此这时候应该将10.10.1.0和12.0/30的RI

37、P路由变为OSPF E2，由于13.0/30为直连不会变当R3也发布后路由时，这个时候R3关于RIP的只有13.0/30这条直连的了所以只会发布13.0/30的5类OSPF到R2,R2收到后发现自己有一条13.0/30的RIP就被取代为OSPF了。 这个时候产生了次佳路由，R3本来时直接由R1到10.10.1.0网段的现在却是经过R4再到R2再到R1，之所以会产生次佳路由是由于路由重发布的规则，路由重发布是发布在路由表中存在的该进程的所有路由以及该进程的直连路由。当R2先发布时会把外部OSPF路由发到R3，而R3本身是RIP 管理距离比OSPF 高，所以会被OSPF路由所代替，这时候在重发布的

38、话就只会发布它的一条直连，因此就会产生次佳路由。要解决的办法一是改变外部进来的OSPF的管理距离使其大于RIP二是进行路由过滤。实验操作及结果：在没有进行重发布是R2 R3的路由表内都应该有各自的RIP信息如下 r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.13.0/30 is subnetted, 1 subnetsR 192.168.13.0 120/1 via 192.168.12.1, 00:00:25, Se

39、rial0/0 192.168.24.0/30 is subnetted, 1 subnetsC 192.168.24.0 is directly connected, Serial0/2 10.0.0.0/24 is subnetted, 1 subnetsR 10.10.1.0 120/1 via 192.168.12.1, 00:00:25, Serial0/0 192.168.34.0/30 is subnetted, 1 subnetsO 192.168.34.0 110/128 via 192.168.24.2, 00:00:37, Serial0/2r3#show ip rout

40、e 192.168.12.0/30 is subnetted, 1 subnetsR 192.168.12.0 120/1 via 192.168.13.1, 00:00:23, Serial0/0 192.168.13.0/30 is subnetted, 1 subnetsC 192.168.13.0 is directly connected, Serial0/0 192.168.24.0/30 is subnetted, 1 subnetsO 192.168.24.0 110/128 via 192.168.34.2, 00:01:19, Serial0/1 10.0.0.0/24 i

41、s subnetted, 1 subnetsR 10.10.1.0 120/1 via 192.168.13.1, 00:00:23, Serial0/0 192.168.34.0/30 is subnetted, 1 subnetsC 192.168.34.0 is directly connected, Serial0/1当将R2重发布进OSPF 后r2(config)#router ospf 1r2(config-router)#redistribute rip subnets r2(config-router)#exitR2不会有变化，R3与R4变了 r3#show ip route

42、192.168.12.0/30 is subnetted, 1 subnetsO E2 192.168.12.0 110/20 via 192.168.34.2, 00:00:02, Serial0/1 192.168.13.0/30 is subnetted, 1 subnetsC 192.168.13.0 is directly connected, Serial0/0 192.168.24.0/30 is subnetted, 1 subnetsO 192.168.24.0 110/128 via 192.168.34.2, 00:00:02, Serial0/1 10.0.0.0/24

43、 is subnetted, 1 subnetsO E2 10.10.1.0 110/20 via 192.168.34.2, 00:00:02, Serial0/1 192.168.34.0/30 is subnetted, 1 subnetsC 192.168.34.0 is directly connected, Serial0/1r4#show ip route 192.168.12.0/30 is subnetted, 1 subnetsO E2 192.168.12.0 110/20 via 192.168.24.1, 00:00:27, Serial0/0 192.168.13.

44、0/30 is subnetted, 1 subnetsO E2 192.168.13.0 110/20 via 192.168.24.1, 00:00:27, Serial0/0 192.168.24.0/30 is subnetted, 1 subnetsC 192.168.24.0 is directly connected, Serial0/0 10.0.0.0/24 is subnetted, 1 subnetsO E2 10.10.1.0 110/20 via 192.168.24.1, 00:00:27, Serial0/0 192.168.34.0/30 is subnette

45、d, 1 subnetsC 192.168.34.0 is directly connected, Serial0/1这时将R3也发布进去，再观察R2 R4的路由表r3(config)#router ospf 1r3(config-router)#redistribute rip subnets r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.13.0/30 is subnetted, 1 subnetsO E2 192

46、.168.13.0 110/20 via 192.168.24.2, 00:00:05, Serial0/2 192.168.24.0/30 is subnetted, 1 subnetsC 192.168.24.0 is directly connected, Serial0/2 10.0.0.0/24 is subnetted, 1 subnetsR 10.10.1.0 120/1 via 192.168.12.1, 00:00:15, Serial0/0 192.168.34.0/30 is subnetted, 1 subnetsO 192.168.34.0 110/128 via 1

47、92.168.24.2, 00:00:05, Serial0/2r4#show ip route 192.168.12.0/30 is subnetted, 1 subnetsO E2 192.168.12.0 110/20 via 192.168.24.1, 00:02:54, Serial0/0 192.168.13.0/30 is subnetted, 1 subnetsO E2 192.168.13.0 110/20 via 192.168.34.1, 00:02:51, Serial0/1 /对比没发布R3时的路由会发现下一跳变了，这是因为R2在路由表中已经没有关于这一条的RIP路由

48、了 192.168.24.0/30 is subnetted, 1 subnetsC 192.168.24.0 is directly connected, Serial0/0 10.0.0.0/24 is subnetted, 1 subnetsO E2 10.10.1.0 110/20 via 192.168.24.1, 00:02:54, Serial0/0 192.168.34.0/30 is subnetted, 1 subnetsC 192.168.34.0 is directly connected, Serial0/1为了避免次佳路由的产生可以通过改变OSPF外部路由的管理距离

49、使其大于RIPr3(config)#router ospf 1r3(config-router)#distance ospf external 130 /将外部OSPF管理距离变为130，内部并没有改变r2#r2(config)#router ospf 1r2(config-router)#distance ospf external 130这时候路由回复正常 r2#show ip route 192.168.12.0/30 is subnetted, 1 subnetsC 192.168.12.0 is directly connected, Serial0/0 192.168.13.0/3

50、0 is subnetted, 1 subnetsR 192.168.13.0 120/1 via 192.168.12.1, 00:00:11, Serial0/0 192.168.24.0/30 is subnetted, 1 subnetsC 192.168.24.0 is directly connected, Serial0/2 10.0.0.0/24 is subnetted, 1 subnetsR 10.10.1.0 120/1 via 192.168.12.1, 00:00:11, Serial0/0 192.168.34.0/30 is subnetted, 1 subnet

51、sO 192.168.34.0 110/128 via 192.168.24.2, 00:00:17, Serial0/2r3#show ip route 192.168.12.0/30 is subnetted, 1 subnetsR 192.168.12.0 120/1 via 192.168.13.1, 00:00:10, Serial0/0 192.168.13.0/30 is subnetted, 1 subnetsC 192.168.13.0 is directly connected, Serial0/0 192.168.24.0/30 is subnetted, 1 subnetsO 192.168.24.0 110/128 via 192.168.34.2, 00:00:38, Serial0/1 10.0.0.0/24 is subnetted, 1 subnetsR 10.10.1.0 12