启用EIGRP(Enabling EIGRP)

R1(config)#router eigrp 10           //启用eigrp路由协议，设置自治系统号为10
R1(config-router)#network 10.1.1.0 0.0.0.255 
R1(config-router)#network 10.2.2.0 0.0.0.31
R1(config-router)#network 10.3.3.0 0.0.0.255
R1(config-router)#no auto-summary     //取消自动汇总
R1(config-router)#exit

R2(config)#router eigrp 10
R2(config-router)#network 10.3.3.0 0.0.0.255
R2(config-router)#network 172.16.3.0 0.0.0.255
R2(config-router)#no auto-summary
R2(config-router)#exit

R3(config)#router eigrp 10
R3(config-router)#network 172.16.3.0 0.0.0.255
R3(config-router)#network 172.16.1.0 0.0.0.255
R3(config-router)#network 172.16.2.0 0.0.0.31
R3(config-router)#no auto-summary
R3(config-router)#exit

注：这里的自治系统号10，三台路由器必须相同。

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

     172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
D       172.16.1.0/24 [90/2809856] via 10.3.3.2, 00:00:11, Serial1/1
D       172.16.2.0/27 [90/2809856] via 10.3.3.2, 00:00:11, Serial1/1
D       172.16.3.0/24 [90/2681856] via 10.3.3.2, 00:00:11, Serial1/1
     10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C       10.3.3.0/24 is directly connected, Serial1/1
C       10.2.2.0/27 is directly connected, Loopback1
C       10.1.1.0/24 is directly connected, Loopback0

R1#show ip eigrp topology 
IP-EIGRP Topology Table for AS(10)/ID(10.2.2.1)

Codes:  P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status 

P 10.3.3.0/24, 1 successors, FD is 2169856
        via Connected, Serial1/1
P 10.2.2.0/27, 1 successors, FD is 128256
        via Connected, Loopback1
P 10.1.1.0/24, 1 successors, FD is 128256
        via Connected, Loopback0
P 172.16.0.0/16, 1 successors, FD is 2681856
        via 10.3.3.2 (2681856/2169856), Serial1/1

R1#show ip eigrp neighbors 
IP-EIGRP neighbors for process 10
H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq
                                            (sec)         (ms)       Cnt Num
0   10.3.3.2                Se1/1             11 00:00:37  126   756  0  5