CCNA--LAB-3：配置EIGRP路由協議

拓補如上：

R1:
Router>en
Router#conf t
Router(config)#hostname R1
R1(config)#interface f0/0
R1(config-if)#ip address 192.168.1.254 255.255.255.0
R1(config-if)#no sh
R1(config-if)#int f0/1
R1(config-if)#ip address 12.1.1.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#router eigrp 100     --進入並啓用EIGRP配置,自治系統號100（兩臺自治系統號需同樣，否則不能創建鄰居關係）
R1(config-router)#no auto-summary      --不要自動彙總
R1(config-router)#network 12.1.1.0 0.0.0.255     --宣告直連網段，反掩碼
R1(config-router)#network 192.168.1.0 0.0.0.255
R1(config-router)#end
R1#

查看路由表：
R1#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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

     12.0.0.0/24 is subnetted, 1 subnets
C       12.1.1.0 is directly connected, FastEthernet0/1
C    192.168.1.0/24 is directly connected, FastEthernet0/0
D    192.168.2.0/24 [90/30720] via 12.1.1.2, 00:01:36, FastEthernet0/1

注：D 192.168.2.0/24 [90/30720] via 12.1.1.2, 00:01:36, FastEthernet0/1

D表示經過EIGRP學習到的， [90/30720]表示管理距離/度量值

R2:
Router>en
Router#conf t
Router(config)#hostname R2
R2(config)#interface f0/0
R2(config-if)#ip address 192.168.2.254 255.255.255.0
R2(config-if)#no sh
R2(config-if)#int f0/1
R2(config-if)#ip address 12.1.1.2 255.255.255.0
R2(config-if)#no sh
R2(config-if)#exit
R2(config)#router eigrp 100
R2(config-router)#no auto-summary
R2(config-router)#network 12.1.1.0 0.0.0.255
R2(config-router)#network 192.168.2.0 0.0.0.255
R2(config-router)#end
R2#

查看路由表：
R2#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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

     12.0.0.0/24 is subnetted, 1 subnets
C       12.1.1.0 is directly connected, FastEthernet0/1
D    192.168.1.0/24 [90/30720] via 12.1.1.1, 00:02:20, FastEthernet0/1
C    192.168.2.0/24 is directly connected, FastEthernet0/0
R2#

驗證在PC0上拼PC1：

PC>ping 192.168.2.1

Pinging 192.168.2.1 with 32 bytes of data:

Reply from 192.168.2.1: bytes=32 time=40ms TTL=126
Reply from 192.168.2.1: bytes=32 time=33ms TTL=126
Reply from 192.168.2.1: bytes=32 time=27ms TTL=126
Reply from 192.168.2.1: bytes=32 time=23ms TTL=126

Ping statistics for 192.168.2.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 23ms, Maximum = 40ms, Average = 30ms

PC>

總結：

Eigrp 的彌散更新算法
1:記錄從鄰居處收到的路由。
2:100%無環路。
3:若是最好路由不可用且存在次好路由，它將會把次好路由變成最好路由。
4:若是最好路由不可用且不存在次好路由，它將會向鄰居發送查詢信息。
保證路由100%無環路的機理：AD<FD

EIGRP優勢：它的收斂速度極快，並且支持非等價負載均衡，支持認證。

缺點：沒有區域的概念，不適於大型網絡，眀是CISCO私有協議。