一、R6为ISP只能配置IP地址，R1-R5的环回为私有网段
1.首先给各个设备分配IP并设置缺省使全网可达，并用ping命令检查
二，R1/2/3为星型的拓扑结构（MGRE），R1为中心站点
R1
[r1]int Tunnel 0/0/0 [r1-Tunnel0/0/0]ip add 192.168.7.1 24 [r1-Tunnel0/0/0]tunnel-protocol gre p2mp [r1-Tunnel0/0/0]source 16.0.0.1 Sep 18 2022 18:43:45-08:00 r1 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/0 has entered the UP state. [r1-Tunnel0/0/0]nhrp network-id 100
R2
[r2]int t0/0/0 [r2-Tunnel0/0/0]ip add 192.168.7.2 24 [r2-Tunnel0/0/0]tunnel-protocol gre p2mp [r2-Tunnel0/0/0]source GigabitEthernet 0/0/0 Sep 18 2022 18:44:47-08:00 r2 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/0 has entered the UP state. [r2-Tunnel0/0/0]nhrp network-id 100 [r2-Tunnel0/0/0]nhrp entry 192.168.7.1 16.0.0.1 register
R3
[r3]int t0/0/0 [r3-Tunnel0/0/0]ip add 192.168.7.3 24 [r3-Tunnel0/0/0]tunnel-protocol gre p2mp [r3-Tunnel0/0/0]source GigabitEthernet 0/0/0 Sep 18 2022 18:46:16-08:00 r3 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/0 has entered the UP state. [r3-Tunnel0/0/0]nhrp network-id 100 [r3-Tunnel0/0/0]nhrp entry 192.168.7.1 16.0.0.1 register
三，R1/4/5为全连的MGRE结构
1.以R1为中心
R1配置
[r1]int t0/0/1 [r1-Tunnel0/0/1]ip add 192.168.8.1 24 [r1-Tunnel0/0/1]tunnel-protocol gre p2mp [r1-Tunnel0/0/1]source 61.0.0.1 Sep 18 2022 19:00:23-08:00 r1 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/1 has entered the UP state. [r1-Tunnel0/0/1]nhrp network-id 200
R4
[r4]int t0/0/1 [r4-Tunnel0/0/1]ip add 192.168.8.2 24 [r4-Tunnel0/0/1]tunnel-protocol gre p2mp [r4-Tunnel0/0/1]source g0/0/0 Sep 18 2022 19:02:34-08:00 r4 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/1 has entered the UP state. [r4-Tunnel0/0/1]nhrp network-id 200 [r4-Tunnel0/0/1]nhrp entry 192.168.8.1 61.0.0.1 register
R5
[r5]int t0/0/1 [r5-Tunnel0/0/1]ip add 192.168.8.3 24 [r5-Tunnel0/0/1]tunnel-protocol gre p2mp [r5-Tunnel0/0/1]source g0/0/0 Sep 18 2022 19:03:48-08:00 r5 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/1 has entered the UP state. [r5-Tunnel0/0/1]nhrp network-id 200 [r5-Tunnel0/0/1]nhrp entry 192.168.8.1 61.0.0.1 register
2.以R4为中心
R4
[r4-Tunnel0/0/1]source 46.0.0.1 [r4-Tunnel0/0/1]nhrp network-id 400
R1
[r1-Tunnel0/0/1]source g0/0/0 [r1-Tunnel0/0/1]nhrp network-id 400 [r1-Tunnel0/0/1]nhrp entry 192.168.8.2 46.0.0.1 register
R5
[r5-Tunnel0/0/1]source g0/0/0 [r5-Tunnel0/0/1]nhrp network-id 400 [r5-Tunnel0/0/1]nhrp entry 192.168.8.2 46.0.0.1 register
3.以R5为中心
R5
[r5-Tunnel0/0/1]source 56.0.0.1 [r5-Tunnel0/0/1]nhrp network-id 500
R1
[r1-Tunnel0/0/1]nhrp network-id 500 [r1-Tunnel0/0/1]nhrp entry 192.168.8.3 56.0.0.1 register
R4
[r4-Tunnel0/0/1]nhrp network-id 500 [r4-Tunnel0/0/1]nhrp entry 192.168.8.3 56.0.0.1 register
四，所有私有网段可以互相通讯，使用OSPF完成
## 由于MGRE环境不支持组播，所以需要开启伪广播 [r1-Tunnel0/0/0]nhrp entry multicast dynamic ## 在R1-5上开启OSPF ## 由于通道p2p为点到点所以改为 broadcast ospf network-type broadcast # 需进入每个接口修改
最后查看路由表且所有私有网段可互相通讯
