实验需求
根据上图可得，实验需求为：
1.R5作为ISP：其上只能配置IP地址；R4作为企业边界路由器，出口公网地址需要通过PPP协议获取，并进行CHAP认证。（PS：因PPP协议尚未学习，在此次实验中不使用）
2.每个OSPF邻居ID 基于IP地址172.16.0.0/16划分；
3.所有设备均可访问R5的环回；
4.减少LSA的数量，加快收敛，保障更新安全；
5.全网可达。
实验思路
1.首先确定网络拓扑结构，根据实验需求搭建网络拓扑图，确定每台路由器的接口以及互联关系。
2.子网划分与OSPF配置
基于IP地址划分OSPF邻居ID：
根据IP地址172.16.0.8/16划分OSPF区域，确保每个邻居ID唯一。
配置OSPF路由协议，并在每个路由器上配置相应的网络命令。
3.配置R5作为ISP
4.网络优化
减少LSA数量：
通过合理规划OSPF区域，使用区域划分来减少LSA的数量。
使用路由汇总来减少LSA的数量。
加快收敛：
配置OSPF的快速收敛特性，如调整Hello和Dead间隔。
确保网络中无环路，避免不必要的路由更新。
保障更新安全：
使用OSPF的认证功能，如明文认证或MD5认证，来保障路由更新安全。
5.配置NAT保证私网能正常访问公网
6.确保全网可达
测试连通性：
使用Ping命令测试网络中每个设备之间的连通性。
确认所有设备均能访问R5的环回接口。
具体划分如下所示：
172,16.64.0 19--area 2
/24
172.16.64.0 24
172.16.65.0 24
172.16.66.0 24
...
P2P---
172.16.64.0 24 -30
172.16.64.0 30
172.16.64.4 30
...
MA
172.16.65.0 24
172.16.65.0 29
172.16.65.8 29
172.16.65.16 29
用户
172.16.66.0 /24
172.16.67.0 /24
配置如下：
AR3配置：
interface GigabitEthernet 0/0/1
ip address 172.16.0.1 30
interface GigabitEthernet 0/0/0
ip address 172.16.32.3 29
interface LoopBack0
ip address 172.16.35.1 24
ospf router-id 3.3.3.3
area 1
network 172.16.32.0 0.0.31.255
area 0
network 172.16.0.1 0.0.0.0
arp-ping
asbr-summary
area 1
stub
stub no-summary
interface GigabitEthernet 0/0/0
ospf timer hello 2
authentication-mode md5 1 cipher 123456
AR4配置：
interface GigabitEthernet 0/0/1
ip address 172.16.0.2 30
interface GigabitEthernet 0/0/2
ip address 172.16.0.5 30
interface GigabitEthernet 0/0/0
ip address 172.16.0.9 30
ospf router-id 4.4.4.4
area 0
network 172.16.0.0 0.0.31.255
interface Serial4/0/0
ppp chap user huawei
ppp chap password cipher 123456
ip address ppp-negotiate
undo shutdown
acl 2000
rule permit source 172.16.0.0 0.0.255.255
interface Serial4/0/0
nat outbound 2000
default-route-advertise always
ip route-static 0.0.0.0 0 45.0.0.2
interface GigabitEthernet 0/0/2
ospf network-type p2p
AR6配置：
interface GigabitEthernet 0/0/1
ip address 172.16.0.6 30
interface LoopBack0
ip address 172.16.2.1 24
interface GigabitEthernet 0/0/0
ip address 172.16.64.1 30
ospf router-id 6.6.6.6
area 0
network 172.16.0.0 0.0.31.255
area 2
network 172.16.64.0 0.0.31.255
abr-summary 172.16.64.0 255.255.224.0
nssa no-import-route
nssa no-summary
interface GigabitEthernet 0/0/1
ospf network-type p2p
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR7配置：
interface GigabitEthernet 0/0/0
ip address 172.16.0.10 30
interface LoopBack0
ip address 172.16.3.1 24
interface GigabitEthernet 0/0/1
ip address 172.16.96.1 30
ospf router-id 7.7.7.7
area 0
network 172.16.0.0 0.0.31.255
area 3
network 172.16.96.0 0.0.31.255
abr-summary 172.16.96.0 255.255.224.0
nssa no-import-route
nssa no-summary
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR1配置：
interface GigabitEthernet 0/0/0
ip address 172.16.32.1 29
interface LoopBack0
ip address 172.16.33.1 24
ospf 1 router-id 1.1.1.1
area 1
network 172.16.0.0 0.0.255.255
interface GigabitEthernet 0/0/0
ospf timer hello 2
authentication-mode md5 1 cipher 123456
AR2配置：
interface GigabitEthernet 0/0/0
ip address 172.16.32.2 29
interface LoopBack0
ip address 172.16.34.1 24
ospf router-id 2.2.2.2
area 1
network 172.16.32.0 0.0.31.255
interface GigabitEthernet 0/0/0
ospf timer hello 2
authentication-mode md5 1 cipher 123456
AR11配置：
interface GigabitEthernet 0/0/0
ip address 172.16.64.2 30
interface GigabitEthernet 0/0/1
ip address 172.16.64.5 30
interface LoopBack0
ip address 172.16.65.1 24
ospf router-id 11.0.0.1
area 2
network 172.16.64.0 0.0.31.255
nssa
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR12配置：
interface GigabitEthernet 0/0/0
ip address 172.16.64.6 30
interface LoopBack0
ip address 172.16.160.1 24
interface LoopBack1
ip address 172.16.161.1 24
ospf router-id 12.0.0.1
area 2
network 172.16.64.0 0.0.31.255
import-route rip
version 2
network 172.16.0.0
asbr-summary 172.16.160.0 255.255.224.0
nssa
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR8配置：
interface GigabitEthernet 0/0/0
ip address 172.16.96.2 30
interface GigabitEthernet 0/0/1
ip address 172.16.96.5 30
interface LoopBack0
ip address 172.16.97.1 24
ospf router-id 8.8.8.8
area 3
network 172.16.96.0 0.0.31.255
nssa
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR9配置：
interface GigabitEthernet 0/0/0
ip address 172.16.96.6 30
interface GigabitEthernet 0/0/1
ip address 172.16.128.1 30
interface LoopBack0
ip address 172.16.129.1 24
ospf router-id 9.9.9.9
area 3
network 172.16.96.0 0.0.31.255
area 4
network 172.16.128.0 0.0.31.255
import-route ospf 2
asbr-summary 172.16.128.0 255.255.224.0
nssa
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR10配置：
interface GigabitEthernet 0/0/0
ip address 172.16.128.2 30
interface LoopBack0
ip address 172.16.130.1 24
ospf router-id 10.0.0.1
area 4
network 172.16.128.0 0.0.31.255
interface GigabitEthernet 0/0/0
ospf timer hello 2
AR5配置：
interface Serial4/0/0
ip address 45.0.0.2 24
local-user huawei password cipher 123456
local-user huawei service-type ppp
interface Serial4/0/0
ppp authentication-mode chap
remote address 54.0.0.1