测试关闭R1的E1和重新启用后路有变化情况。

r1-2514#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, 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

C    1.0.0.0/8 is directly connected, Loopback0
     172.16.0.0/24 is subnetted, 2 subnets
O E2    172.16.1.0 [110/100] via 10.0.3.3, 00:00:25, Ethernet0
O E2    172.16.3.0 [110/100] via 10.0.3.3, 00:00:25, Ethernet0
     10.0.0.0/24 is subnetted, 5 subnets
C       10.0.2.0 is directly connected, Serial1
C       10.0.3.0 is directly connected, Ethernet0
C       10.0.1.0 is directly connected, Ethernet1
O       10.0.4.0 [110/20] via 10.0.3.3, 00:00:25, Ethernet0
O       10.0.5.0 [110/84] via 10.0.3.3, 00:00:26, Ethernet0
r1-2514#ping 10.0.2.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 184/184/184 ms
r1-2514#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
r1-2514(config)#int e0
r1-2514(config-if)#shut
r1-2514(config-if)#
*Mar  1 00:04:15.191: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on Ethernet0 from FULL to DOWN, Neighbor Down: Interface down or detached
r1-2514(config-if)#
*Mar  1 00:04:17.183: %LINK-5-CHANGED: Interface Ethernet0, changed state to administratively down
*Mar  1 00:04:18.183: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0, changed state to down
r1-2514(config-if)#end
r1-2514#show ip 
*Mar  1 00:04:20.823: %SYS-5-CONFIG_I: Configured from console by console
r1-2514#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, 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

C    1.0.0.0/8 is directly connected, Loopback0
     172.16.0.0/24 is subnetted, 2 subnets
O E2    172.16.1.0 [110/100] via 10.0.2.2, 00:00:06, Serial1
O E2    172.16.3.0 [110/100] via 10.0.2.2, 00:00:06, Serial1
     10.0.0.0/24 is subnetted, 4 subnets
C       10.0.2.0 is directly connected, Serial1
C       10.0.1.0 is directly connected, Ethernet1
O       10.0.4.0 [110/138] via 10.0.2.2, 00:00:06, Serial1
O       10.0.5.0 [110/128] via 10.0.2.2, 00:00:06, Serial1
r1-2514#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
r1-2514(config)#int e0
r1-2514(config-if)#no shu
r1-2514(config-if)#
*Mar  1 00:04:48.251: %LINK-3-UPDOWN: Interface Ethernet0, changed state to up
*Mar  1 00:04:49.251: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0, changed state to up
r1-2514(config-if)#end
r1-2514#
*Mar  1 00:04:53.171: %SYS-5-CONFIG_I: Configured from console by console
r1-2514#
*Mar  1 00:04:56.299: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on Ethernet0 from LOADING to FULL, Loading Done
r1-2514#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, 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

C    1.0.0.0/8 is directly connected, Loopback0
     172.16.0.0/24 is subnetted, 2 subnets
O E2    172.16.1.0 [110/100] via 10.0.3.3, 00:00:02, Ethernet0
O E2    172.16.3.0 [110/100] via 10.0.3.3, 00:00:02, Ethernet0
     10.0.0.0/24 is subnetted, 5 subnets
C       10.0.2.0 is directly connected, Serial1
C       10.0.3.0 is directly connected, Ethernet0
C       10.0.1.0 is directly connected, Ethernet1
O       10.0.4.0 [110/20] via 10.0.3.3, 00:00:02, Ethernet0
O       10.0.5.0 [110/84] via 10.0.3.3, 00:00:03, Ethernet0
r1-2514#