第一步：给R1,R2,R3,R4配IP
R1-GigabitEthernet0/0/0ip address 192.168.1.1 24
R1-Serial4/0/0ip address 15.0.0.1 24
R2-GigabitEthernet0/0/0ip address 192.168.2.1 24
R2-Serial4/0/0ip address 25.0.0.1 24
R3-GigabitEthernet0/0/0ip address 192.168.3.1 24
R3-Serial4/0/0ip address 35.0.0.1 24
R4-GigabitEthernet0/0/0ip address 192.168.4.1 24
第二步：认证配置
给R1和R5间使用PPP的PAP认证;
ISP设密码
ISP-aaalocal-user huawei password cipher 123456
定义服务对象：
ISP-aaalocal-user huawei service-type ppp
ISP-Serial3/0/0ppp authentication-mode pap、
重新协商链路：
R1-Serial4/0/0shutdown
R1-Serial4/0/0undo shutdown
协议层面（protocol）是down就密码和账号就建立成功了
s 40/0/0认证成功
补全认证
R1-Serial4/0/0ppp pap local-user huawei password cipher 12345
R1-Serial4/0/0shutdown
R1-Serial4/0/0undo shutdown
s 4/0/0 都up，认证成功。
R2与R5之间使用PPP的chap认证，R5为主认证方：
R2-Serial4/0/0ppp chap user huawei 创建账号
R2-Serial4/0/0ppp chap password cipher 123456 设密码
R1-Serial4/0/0shutdown
R1-Serial4/0/0undo shutdown 认证
都up,认证成功
R3与R5之间使用HDLC封装
ISP-Serial4/0/0link-protocol hdlc
第三步：构建MGRE环境
配置静态路由
R1ip route-static 0.0.0.0 0 15.0.0.2
R2ip route-static 0.0.0.0 0 25.0.0.2
R3ip route-static 0.0.0.0 0 35.0.0.2
R4ip route-static 0.0.0.0 0 45.0.0.2
建立隧道
R1int t0/0/0
R1-Tunnel0/0/0ip address 192.168.5.1 24
R1-Tunnel0/0/0tunnel-protocol gre p2mp
R1-Tunnel0/0/0shutdown
R1-Tunnel0/0/0source 15.0.0.1
R1-Tunnel0/0/0nhrp network-id 100
R2int t0/0/0
R2-Tunnel0/0/0ip address 192.168.5.2 24
R2-Tunnel0/0/0tunnel-protocol gre p2mp
R2-Tunnel0/0/0shutdown
R2-Tunnel0/0/0source s4/0/0
R2-Tunnel0/0/0nhrp network-id 100
R2-Tunnel0/0/0nhrp entry 192.168.5.1 15.0.0.1 register
R3int t0/0/0
R3-Tunnel0/0/0ip address 192.168.5.3 24
R3-Tunnel0/0/0tunnel-protocol gre p2mp
R3-Tunnel0/0/0shutdown
R3-Tunnel0/0/0source s4/0/0
R3-Tunnel0/0/0nhrp network-id 100
R3-Tunnel0/0/0nhrp entry 192.168.5.1 15.0.0.1 register
R1-Tunnel0/0/0int t0/0/1
R1-Tunnel0/0/1ip address 192.168.6.1 24
R1-Tunnel0/0/1tunnel-protocol gre
R1-Tunnel0/0/1shutdown
R1-Tunnel0/0/1source 15.0.0.1
R1-Tunnel0/0/1description 45.0.0.1
R4int t0/0/0
R4-Tunnel0/0/0ip address 192.168.6.2 24
R4-Tunnel0/0/0tunnel-protocol gre
R4-Tunnel0/0/0shutdown
R4-Tunnel0/0/0source 45.0.0.1
R4-Tunnel0/0/0description 15.0.0.1
第四步：rip全网可达
R1rip
R1-rip-1version 2
R1-rip-1ne 192.168.1.0
R1-rip-1ne 192.168.5.0
R1-rip-1ne 192.168.6.0
R2rip
R2-rip-1version 2
R2-rip-1network 192.168.5.0
R2-rip-1network 192.168.2.0
R3rip
R3-rip-1verify-source
R3-rip-1version 2
R3-rip-1network 192.168.3.0
R3-rip-1network 192.168.5.0
R4rip
R4-rip-1version 2
R4-rip-1network 192.168.4.0
R1-Tunnel0/0/0nhrp entry multicast dynamic
R1-Tunnel0/0/0undo rip split-horizon
第五步：可访问R5环回
R1acl 2000
R1-acl-basic-2000rule 5 permit source 192.168.1.0 0.0.0.255
R1int s4/0/0
R1-Serial4/0/0nat out
R1-Serial4/0/0nat outbound 2000
