一，拓扑
二，要求
1，R6为ISP只能配置IP地址，R1-R5的环回为私有网段
2，R1/4/5为全连的MGRE结构，R1/2/3为星型的拓扑结构，
3，R1为中心站点所有私有网段可以互相通讯，私有网段使用osPF完成
三，配置
r1
IP配置：
[r1]interface GigabitEthernet 0/0/0
[r1-GigabitEthernet0/0/0]ip address 16.0.0.1 24
[r1]interface GigabitEthernet 0/0/1
[r1-GigabitEthernet0/0/1]ip address 17.0.0.1 24
[r1]interface LoopBack 0
[r1-LoopBack0]ip address 192.168.1.1 24
缺省路由：
[r1]ip route-static 0.0.0.0 0 16.0.0.2
[r1]ip route-static 0.0.0.0 0 17.0.0.2
隧道接口配置：
[r1]interface Tunnel 0/0/0
[r1-Tunnel0/0/0]ip address 10.1.1.1 24
[r1-Tunnel0/0/0]tunnel-protocol gre p2mp
[r1-Tunnel0/0/0]source 16.0.0.1
[r1-Tunnel0/0/0]ospf network-type broadcast //修改接口类型
[r1-Tunnel0/0/0]nhrp entry multicast dynamic//开启伪广播来实现OSPF的组播功能
隧道接口配置：
[r1]interface Tunnel 0/0/1
[r1-Tunnel0/0/1]shutdown //关闭接口，方便配置实现
[r1-Tunnel0/0/1]ip address 10.1.2.1 24
[r1-Tunnel0/0/1]tunnel-protocol gre p2mp
[r1-Tunnel0/0/1]source GigabitEthernet 0/0/1
[r1-Tunnel0/0/1]nhrp entry 10.1.2.2 46.0.0.1 register
[r1-Tunnel0/0/1]nhrp entry 10.1.2.3 56.0.0.1 register
[r1-Tunnel0/0/1]ospf network-type broadcast
OSPF配置：
[r1]ospf 1 router-id 1.1.1.1
[r1-ospf-1]are
[r1-ospf-1]area 0
[r1-ospf-1-area-0.0.0.0]net
[r1-ospf-1-area-0.0.0.0]network 10.1.1.0 0.0.0.255
[r1-ospf-1-area-0.0.0.0]network 10.1.2.0 0.0.0.255
[r1-ospf-1-area-0.0.0.0]network 192.168.1.0 0.0.0.255
[r1]interface Tunnel 0/0/1 //开启接口
[r1-Tunnel0/0/1]undo shutdown
r2
IP配置：
[r2]interface GigabitEthernet 0/0/0
[r2-GigabitEthernet0/0/0]ip address 26.0.0.1 24
[r2]interface LoopBack 0
[r2-LoopBack0]ip address 192.168.2.1 24
缺省路由：
[r2]ip route-static 0.0.0.0 0 26.0.0.2
隧道接口配置：
[r2]interface Tunnel 0/0/0
[r2-Tunnel0/0/0]ip address 10.1.1.2 24
[r2-Tunnel0/0/0]tunnel-protocol gre p2mp
[r2-Tunnel0/0/0]source GigabitEthernet 0/0/0
[r2-Tunnel0/0/0]nhrp entry 10.1.1.1 16.0.0.1 register
[r2-Tunnel0/0/0]ospf network-type broadcast
[r2-Tunnel0/0/0]ospf dr-priority 0
OSPF配置：
[r2]ospf 1 router-id 2.2.2.2
[r2-ospf-1]area 0
[r2-ospf-1-area-0.0.0.0]network 10.1.1.0 0.0.0.255
[r2-ospf-1-area-0.0.0.0]network 192.168.2.0 0.0.0.255
r3
IP配置：
[r3]interface GigabitEthernet 0/0/0
[r3-GigabitEthernet0/0/0]ip address 36.0.0.1 24
[r3]interface LoopBack 0
[r3-LoopBack0]ip address 192.168.3.1 24
缺省路由：
[r3]ip route-static 0.0.0.0 0 36.0.0.2
隧道接口配置：
[r3]interface Tunnel 0/0/0
[r3-Tunnel0/0/0]ip address 10.1.1.3 24
[r3-Tunnel0/0/0]tunnel-protocol gre p2mp
[r3-Tunnel0/0/0]source GigabitEthernet 0/0/0
[r3-Tunnel0/0/0]nhrp entry 10.1.1.1 16.0.0.1 register
[r3-Tunnel0/0/0]ospf network-type broadcast
OSPF配置：
[r3]ospf 1 router-id 3.3.3.3
[r3-ospf-1]area 0
[r3-ospf-1-area-0.0.0.0]network 192.168.3.0 0.0.0.255
[r3-ospf-1-area-0.0.0.0]network 10.1.1.0 0.0.0.255
r4
IP配置：
[r4]interface GigabitEthernet 0/0/0
[r4-GigabitEthernet0/0/0]ip address 46.0.0.1 24
[r4]interface LoopBack 0
[r4-LoopBack0]ip address 192.168.4.1 24
缺省路由：
[r4]ip route-static 0.0.0.0 0 46.0.0.2
隧道接口配置：
[r4]interface Tunnel 0/0/0
[r4-Tunnel0/0/0]shutdown
[r4-Tunnel0/0/0]ip address 10.1.2.2 24
[r4-Tunnel0/0/0]tunnel-protocol gre p2mp
[r4-Tunnel0/0/0]source GigabitEthernet 0/0/0
[r4-Tunnel0/0/0]nhrp entry 10.1.2.1 17.0.0.1 register
[r4-Tunnel0/0/0]nhrp entry 10.1.2.3 56.0.0.1 register
[r4-Tunnel0/0/0]ospf network-type broadcast
OSPF配置：
[r4]ospf 1 router-id 4.4.4.4
[r4-ospf-1]area 0
[r4-ospf-1-area-0.0.0.0]network 192.168.4.0 0.0.0.255
[r4-ospf-1-area-0.0.0.0]network 10.1.2.0 0.0.0.255
开启接口
[r4]interface Tunnel 0/0/0
[r4-Tunnel0/0/0]undo shutdown
r5IP配置：
[r5]interface GigabitEthernet 0/0/0
[r5-GigabitEthernet0/0/0]ip address 56.0.0.1 24
[r5]interface LoopBack 0
[r5-LoopBack0]ip address 192.168.5.1 24
缺省路由：
[r5]ip route-static 0.0.0.0 0 56.0.0.2
隧道接口配置：
[r5]interface Tunnel 0/0/0
[r5-Tunnel0/0/0]shutdown
[r5-Tunnel0/0/0]ip address 10.1.2.3 24
[r5-Tunnel0/0/0]tunnel-protocol gre p2mp
[r5-Tunnel0/0/0]source GigabitEthernet 0/0/0
[r5-Tunnel0/0/0]nhrp entry 10.1.2.1 17.0.0.1 register
[r5-Tunnel0/0/0]nhrp entry 10.1.2.2 46.0.0.1 register
[r5-Tunnel0/0/0]ospf network-type broadcast
OSPF配置：
[r5]ospf 1 router-id 5.5.5.5
[r5-ospf-1]area 0
[r5-ospf-1-area-0.0.0.0]network 192.168.5.0 0.0.0.255
[r5-ospf-1-area-0.0.0.0]network 10.1.2.0 0.0.0.255
[r5]interface Tunnel 0/0/0
[r5-Tunnel0/0/0]undo shutdown
r6
IP配置：
[r6]interface GigabitEthernet 4/0/0
[r6-GigabitEthernet4/0/0]ip address 17.0.0.2 24
[r6]interface GigabitEthernet 0/0/0
[r6-GigabitEthernet0/0/0]ip address 16.0.0.2 24
[r6]interface GigabitEthernet 0/0/1
[r6-GigabitEthernet0/0/1]ip address 26.0.0.2 24
[r6]interface GigabitEthernet 0/0/2
[r6-GigabitEthernet0/0/2]ip address 36.0.0.2 24
[r6]interface GigabitEthernet 2/0/0
[r6-GigabitEthernet2/0/0]ip address 46.0.0.2 24
[r6]interface GigabitEthernet 3/0/0
[r6-GigabitEthernet3/0/0]ip address 56.0.0.2 24
四，测试
