要求：
1、 R1、R2、R5、R6的環回172.16.0.0/16之間互訪通過R3, 192.16.0.0/16環回互訪通過R4
2、 R3和R4互爲備份
3、 R3和R4的網段出現問題時通過R7,不然不走R7
主要配置：
R1
interface Loopback0
ip address 172.16.1.1 255.255.255.0
interface Loopback1
ip address 192.168.1.1 255.255.255.0
interface Loopback2
ip address 1.1.1.1 255.255.255.0
interface Serial0/0
ip address 12.1.1.1 255.255.255.0
interface Serial0/1
ip address 13.1.1.1 255.255.255.0
router eigrp 90
network 0.0.0.0
offset-list 1 in 1 Serial0/1
access-list 1 permit 192.168.0.0 0.0.255.255
R2
interface Loopback0
ip address 172.16.2.2 255.255.255.0
interface Loopback1
ip address 192.168.2.2 255.255.255.0
interface Loopback2
ip address 2.2.2.2 255.255.255.0
interface Serial0/0
ip address 12.1.1.2 255.255.255.0
interface Serial0/1
ip address 24.1.1.1 255.255.255.0
router eigrp 90
network 0.0.0.0
offset-list 1 in 1 Serial0/1
access-list 1 permit 172.16.0.0 0.0.255.255
R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0
interface Serial0/0
ip address 13.1.1.2 255.255.255.0
interface Serial0/1
ip address 34.1.1.1 255.255.255.0
interface Serial0/2
ip address 35.1.1.1 255.255.255.0
interface Serial0/3
ip address 37.1.1.1 255.255.255.0
router eigrp 90
network 0.0.0.0
offset-list 1 in 1024001 Serial0/0
offset-list 1 in 1024001 Serial0/2
access-list 1 permit 192.168.0.0 0.0.255.255
R4
interface Loopback0
ip address 4.4.4.4 255.255.255.0
interface Serial0/0
ip address 24.1.1.2 255.255.255.0
interface Serial0/1
ip address 34.1.1.2 255.255.255.0
interface Serial0/2
ip address 46.1.1.1 255.255.255.0
interface Serial0/3
ip address 47.1.1.1 255.255.255.0
router eigrp 90
network 0.0.0.0
offset-list 1 in 1024001 Serial0/2
offset-list 1 out 1 Serial0/0
offset-list 1 in 1024001 Serial0/0
access-list 1 permit 172.16.0.0 0.0.255.255
R5
interface Loopback0
ip address 172.16.5.5 255.255.255.0
ip address 192.168.5.5 255.255.255.0
interface Loopback2
ip address 5.5.5.5 255.255.255.0
interface Serial0/0
ip address 35.1.1.2 255.255.255.0
interface Serial0/1
ip address 56.1.1.1 255.255.255.0
interface Serial0/2
ip address 57.1.1.1 255.255.255.0
router eigrp 90
network 0.0.0.0
offset-list 1 in 1 Serial0/0
access-list 1 permit 192.168.0.0 0.0.255.255
R6
interface Loopback0
ip address 172.16.6.6 255.255.255.0
interface Loopback1
ip address 192.168.6.6 255.255.255.0
interface Loopback2
ip address 6.6.6.6 255.255.255.0
interface Serial0/0
ip address 46.1.1.2 255.255.255.0
interface Serial0/1
ip address 56.1.1.2 255.255.255.0
interface Serial0/2
ip address 67.1.1.1 255.255.255.0
router eigrp 90
network 0.0.0.0
offset-list 1 in 1 Serial0/0
!
access-list 1 permit 172.16.0.0 0.0.255.255
R7
interface Loopback0
ip address 7.7.7.7 255.255.255.0
interface Serial0/0
ip address 37.1.1.2 255.255.255.0
ip summary-address eigrp 90 172.16.0.0 255.255.0.0
ip summary-address eigrp 90 192.168.0.0 255.255.0.0
interface Serial0/1
ip address 47.1.1.2 255.255.255.0
ip summary-address eigrp 90 172.16.0.0 255.255.0.0
ip summary-address eigrp 90 192.168.0.0 255.255.0.0
interface Serial0/2
ip address 57.1.1.2 255.255.255.0
ip summary-address eigrp 90 172.16.0.0 255.255.0.0
ip summary-address eigrp 90 192.168.0.0 255.255.0.0
interface Serial0/3
ip address 67.1.1.2 255.255.255.0
ip summary-address eigrp 90 172.16.0.0 255.255.0.0
ip summary-address eigrp 90 192.168.0.0 255.255.0.0