EIGRP路由协议的配置拓扑图

1. R1(config)#router eigrp 100
2. R1(config-router)#no auto-summary //关闭自动汇总
3. R1(config-router)#net 192.168.1.0 //宣告路由条目
4. R1(config-router)#end
5.  
6. R2(config)#router eigrp 100
7. R2(config-router)#no auto-summary
8. R2(config-router)#net 192.168.1.0
9. R2(config-router)#net 10.1.0.0 0.0.255.255 //宣告路由条目
10. R2(config-router)#end
11.  
12. R3(config)#router eigrp 100
13. R3(config-router)#no auto-summary
14. R3(config-router)#net 192.168.1.0
15. R3(config-router)#net 172.16.0.0 0.0.255.255
16. R3(config-router)#end

检查：

1. R1#show ip eigrp neighbors //查看eigrp 邻居表，发现并没有邻居
2. IP-EIGRP neighbors for process 100
3.  
4. R1#show ip eigrp topology //查看EIGRP 拓扑表，并没有学习到任何的路由
5. IP-EIGRP Topology Table for AS(100)/ID(192.168.1.1)
6.  
7. Codes: P – Passive, A – Active, U – Update, Q – Query, R – Reply,
8. r – reply Status, s – sia Status
9.  
10. P 192.168.1.0/24, 1 successors, FD is 2169856
11. via Connected, Serial0/0

因为帧中继默认为NBMA 模式，也就是非广播的多路访问模式，它会阻止广播数据和组播数据，我们在接口配置过程中，帧中继的DLCI 号和IP 映射时也没有配置broadcast 参数，而EIGRP 路由协议通过组播地址224.0.0.10 来发送相应的路由信息（比如hello、update 等数据包），所以R1 并没有发现任何的邻居路由器。
为了能让EIGRP的路由信息通过帧中继传播，在没有配置broadcast 参数的情况下，我们可以通过单播的形式来发送EIGRP 数据包，我们对以上的配置进行改进：

1. R1(config)#router eigrp 100
2. R1(config-router)#neighbor 192.168.1.2 serial 0/0 //手工指定邻居，实现单播方式
3. R1(config-router)#neighbor 192.168.1.3 serial 0/0
4. R1(config-router)#end
5.  
6. R2(config)#router eigrp 100
7. R2(config-router)#neighbor 192.168.1.1 serial 0/0 //手工指定邻居，实现单播方式
8. R2(config-router)#end
9.  
10. R3(config)#router eigrp 100
11. R3(config-router)#neighbor 192.168.1.1 serial 0/0 //手工指定邻居，实现单播方式
12. R3(config-router)#end

验证：

1. *Mar 1 00:29:18.955: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.2 (Serial0/0) is up: new adjacency
2. *Mar 1 00:29:19.115: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.3 (Serial0/0) is up: new adjacency
3. R1#show ip eigrp neighbors
4. IP-EIGRP neighbors for process 100
5. H Address Interface Hold Uptime SRTT RTO Q Seq
6. (sec) (ms) Cnt Num
7. 1 192.168.1.3 Se0/0 156 00:01:19 99 594 0 3
8. 0 192.168.1.2 Se0/0 154 00:01:19 137 822 0 3
9.  
10. R2#
11. *Mar 1 00:29:18.979: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.1 (Serial0/0) is up: new adjacency
12. R2#
13. R2#show ip eigrp neighbor
14. IP-EIGRP neighbors for process 100
15. H Address Interface Hold Uptime SRTT RTO Q Seq
16. (sec) (ms) Cnt Num
17. 0 192.168.1.1 Se0/0 138 00:02:31 171 1026 0 7

R1#show ip route eigrp 100 //查看路由表，可以看到R1 能够学习到R2 和R3 相应的网络

1. 172.16.0.0/24 is subnetted, 4 subnets
2. D 172.16.0.0 [90/2297856] via 192.168.1.3, 00:03:45, Serial0/0
3. D 172.16.1.0 [90/2297856] via 192.168.1.3, 00:03:45, Serial0/0
4. D 172.16.2.0 [90/2297856] via 192.168.1.3, 00:03:45, Serial0/0
5. D 172.16.3.0 [90/2297856] via 192.168.1.3, 00:03:45, Serial0/0
6. 10.0.0.0/24 is subnetted, 4 subnets
7. D 10.1.3.0 [90/2297856] via 192.168.1.2, 00:03:45, Serial0/0
8. D 10.1.2.0 [90/2297856] via 192.168.1.2, 00:03:45, Serial0/0
9. D 10.1.1.0 [90/2297856] via 192.168.1.2, 00:03:45, Serial0/0
10. D 10.1.0.0 [90/2297856] via 192.168.1.2, 00:03:45, Serial0/0

R1#ping 10.1.0.1 //验证是否可以访问R2 的网络

1. Type escape sequence to abort.
2. Sending 5, 100-byte ICMP Echos to 10.1.0.1, timeout is 2 seconds:
3. !!!!!
4. Success rate is 100 percent (5/5), round-trip min/avg/max = 20/56/104 ms
5. R1#ping 172.16.0.1 //验证是否可以访问R3 的网络
6.  
7. Type escape sequence to abort.
8. Sending 5, 100-byte ICMP Echos to 172.16.0.1, timeout is 2 seconds:
9. !!!!!
10. Success rate is 100 percent (5/5), round-trip min/avg/max = 8/52/124 ms

查看R2 的路由表：

1. R2#show ip route
2. Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP
3. D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
4. N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
5. E1 – OSPF external type 1, E2 – OSPF external type 2
6. i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
7. ia – IS-IS inter area, * – candidate default, U – per-user static route
8. o – ODR, P – periodic downloaded static route
9.  
10. Gateway of last resort is not set
11.  
12. 10.0.0.0/24 is subnetted, 4 subnets
13. C 10.1.3.0 is directly connected, Loopback3
14. C 10.1.2.0 is directly connected, Loopback2
15. C 10.1.1.0 is directly connected, Loopback1
16. C 10.1.0.0 is directly connected, Loopback0
17. C 192.168.1.0/24 is directly connected, Serial0/0
18. 发现R2 并没有学习到R3 的172.16.0.0 网络， R1 通过S0/0 接口学习到R3 宣告的172.16.0.0网络，因为R1 s0/0 接口的水平分割机制导致R1 不会再由这个接口S0/0 发布出去，所以R2无法学习到R3 宣告的网络，同理，R3 也无法学习到R2 宣告的网络。
    对帧中继配置进行修正，使用broadcast 参数：
    
    1. R1(config)#router eigrp 100
    2. R1(config-router)#no neighbor 192.168.1.2 s0/0 //取消手工指定邻居
    3. *Mar 1 00:42:29.807: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.2 (Serial0/0) is down:
    4. R1(config-router)#no neighbor 192.168.1.3 s0/0
    5. *Mar 1 00:42:32.623: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.3 (Serial0/0) is down:
    6. R1(config-router)#exit
    7. R1(config)#int s0/0
    8. R1(config-if)#no fram map ip 192.168.1.2 102 //取消之前不带broadcast 参数的静态映射
    9. R1(config-if)#no fram map ip 192.168.1.3 103
    10. R1(config-if)#frame map ip 192.168.1.2 102 broadcast
    11. R1(config-if)#frame map ip 192.168.1.3 103 broadcast
    12. R1(config-if)#end
    13.  
    14. R2(config)#router eigrp 100
    15. R2(config-router)#no neighbor 192.168.1.1 Serial0/0
    16. R2(config-router)#int s0/0
    17. R2(config-if)#no frame-relay map ip 192.168.1.1 201
    18. R2(config-if)# frame-relay map ip 192.168.1.1 201 broadcast
    19.  
    20. R3(config)#router eigrp 100
    21. R3(config-router)#no neighbor 192.168.1.1 Serial0/0
    22. R3(config-router)#int s0/0
    23. R3(config-if)#no
    24. *Mar 1 00:47:58.943: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.1 (Serial0/0) is up: new adjacency
    25. R3(config-if)#no frame-relay map ip 192.168.1.1 301
    26. R3(config-if)#frame-relay map ip 192.168.1.1 301 broadcast
    27. R3(config-if)#end
    验证结果：
    可以看到添加了broadcast 后，帧中继可以正常的传递组播数据了，R1 就可以和R2 和R3 建立邻居关系并正常学习到路由。
    
    1. R1#show ip eigrp neighbors
    2. IP-EIGRP neighbors for process 100
    3. H Address Interface Hold Uptime SRTT RTO Q Seq
    4. (sec) (ms) Cnt Num
    5. 1 192.168.1.3 Se0/0 178 00:00:03 906 5000 0 7
    6. 0 192.168.1.2 Se0/0 178 00:01:57 1040 5000 0 6
    7. R1#show ip route eigrp 100
    8. 172.16.0.0/24 is subnetted, 4 subnets
    9. D 172.16.0.0 [90/2297856] via 192.168.1.3, 00:00:53, Serial0/0
    10. D 172.16.1.0 [90/2297856] via 192.168.1.3, 00:00:53, Serial0/0
    11. D 172.16.2.0 [90/2297856] via 192.168.1.3, 00:00:53, Serial0/0
    12. D 172.16.3.0 [90/2297856] via 192.168.1.3, 00:00:53, Serial0/0
    13. 10.0.0.0/24 is subnetted, 4 subnets
    14. D 10.1.3.0 [90/2297856] via 192.168.1.2, 00:02:46, Serial0/0
    15. D 10.1.2.0 [90/2297856] via 192.168.1.2, 00:02:46, Serial0/0
    16. D 10.1.1.0 [90/2297856] via 192.168.1.2, 00:02:46, Serial0/0
    17. D 10.1.0.0 [90/2297856] via 192.168.1.2, 00:02:46, Serial0/0
    查看R3 的路由表，发现R3 并没有学习到R2 的网络，这是因为R1 默认情况下接口有水平。
    
    1. R3#show ip route
    2. Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP
    3. D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
    4. N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
    5. E1 – OSPF external type 1, E2 – OSPF external type 2
    6. i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
    7. ia – IS-IS inter area, * – candidate default, U – per-user static route
    8. o – ODR, P – periodic downloaded static route
    9.  
    10. Gateway of last resort is not set
    11.  
    12. 172.16.0.0/24 is subnetted, 4 subnets
    13. C 172.16.0.0 is directly connected, Loopback0
    14. C 172.16.1.0 is directly connected, Loopback1
    15. C 172.16.2.0 is directly connected, Loopback2
    16. C 172.16.3.0 is directly connected, Loopback3
    17. C 192.168.1.0/24 is directly connected, Serial0/0
    将R1 接口的水平分割关闭：
    
    1. R1(config)#interface serial 0/0
    2. R1(config-if)#no ip split-horizon eigrp 100
    3. R1(config-if)#end
    当R1 的水平分割关闭后，EIGRP 进程会出现相应提示：
    
    1. *Mar 1 00:52:25.055: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.3 (Serial0/0) is resync: split horizon changed
    2. *Mar 1 00:52:25.055: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.1.2 (Serial0/0) is resync: split horizon changed
    查看R1 接口S0/0 的情况：
    
    1. R1#show ip int s0/0 | include Split
    2. Split horizon is disabled
    查看R2 的路由表：
    
    1. R2#show ip route eigrp 100
    2. 172.16.0.0/24 is subnetted, 4 subnets
    3. D 172.16.0.0 [90/2809856] via 192.168.1.1, 00:08:03, Serial0/0
    4. D 172.16.1.0 [90/2809856] via 192.168.1.1, 00:08:03, Serial0/0
    5. D 172.16.2.0 [90/2809856] via 192.168.1.1, 00:08:03, Serial0/0
    6. D 172.16.3.0 [90/2809856] via 192.168.1.1, 00:08:03, Serial0/0
    虽然R2 路由表中有172.16.2.0/24 网络，但R2 并没有ping 通，这是什么原因？
    因为R3 的串行口帧中继配置时，只做了IP 192.168.1.1 和DLCI 号的对应，没有做IP 192。168.1.2 和DLCI 号的映射，所以R2 ping 172.16.2.1 时，采用的源地址为192.168.1.2，通过路由表发现目的地址172.16.2.1 具有符合的条目，转发接口为192.168.1.1，于是由R1 转发到R3，R3 在回包过程时，源地址为172.16.2.1，而目标地址为192.168.1.2，但它不知道这个地址怎么转发于是就丢弃。
    
    1. R3(config)#int s0/0
    2. R3(config-if)#frame-relay map ip 192.168.1.2 301 broadcast
    3. R2(config-if)#end
    4.  
    5. R2(config)#int s0/0
    6. R2(config-if)#frame-relay map ip 192.168.1.3 201 broadcast
    7. R2(config-if)#end
    验证结果：
    
    1. R2#ping 172.16.1.1
    2.  
    3. Type escape sequence to abort.
    4. Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:
    5. !!!!!
    6. Success rate is 100 percent (5/5), round-trip min/avg/max = 44/88/160 ms
    帧中继的配置结束了，验证结果大家已经清楚地看到，所以如上所述内容是一个很有说明力度的实例，对于读者了解EIGRP路由协议的配置是很有帮助的。更多内容请读者阅读：
    帧中继交换机和路由器模拟配置和CCNP：EIGRP带宽实例配置解析