一需求
1.除了R5的环回地址固定5.5.5.0/24，其他网段基于192.168.1.0/24进行合理划分；
2.R1-R4每个路由器存在两个环回接口，模拟PC，地址也在192.168.1.0/24网络内；
3.R1-R4不能直接编写到达5.5.5.0/24的静态路由，但依然可以访问；
4.全网可达，尽量减少每台路由器路由条目数量，避免环路；
5.R4与R5间，正常1000M链路通信，故障时自动改为100M；
二分析
1.基于192.168.1.0/24进行合理划分，查看广播域，一共有几个网段
2.R1-R4每个路由器存在两个环回接口，模拟PC，有8个环回网段
3.R1-R4不能直接编写到达5.5.5.0/24的静态路由，但依然可以访问；用缺省路由解决
4..全网可达，尽量减少每台路由器路由条目数量，避免环路，路由汇总和ip route-static 10.1.0.0 20 null0 黑洞路由解决
5..R4与R5间，正常1000M链路通信，故障时自动改为100M；用优先级解决
三
IP地址分配
8个环回网段
6个骨干链路网段
将192.168.1.0/24划分为两个子网
192.168.1.0/25 给骨干链路使用
192.168.1.128/25给环回网段使用
先做骨干链路的需求：
192.168.1.0 00000 00 192.168.1.0/30
192.168.1.0 00001 00 192.168.1.4/30
192.168.1.0 00010 00 192.168.1.8/30
192.168.1.0 00011 00 192.168.1.12/30
192.168.1.0 00100 00 192.168.1.16/30
192.168.1.0 00101 00 192.168.1.20/30
环回网段：
192.168.1.128/25 划分为四个子网，每个子网再分别换分为两个子网
192.168.1.1 00 00000 192.168.1.128/27 给R1的环回使用
192.168.1.1 01 00000 192.168.1.160/27 给R2的环回使用
192.168.1.1 10 00000 192.168.1.192/27 给R3的环回使用
192.168.1.1 11 00000 192.168.1.224/27 给R4的环回使用
R1的两个环回：192.168.1.128/28 192.168.1.144/28
R2的两个环回：192.168.1.160/28 192.168.1.176/28
R3的两个环回：192.168.1.192/28 192.168.1.208/28
R4的两个环回：192.168.1.224/28 192.168.1.240/28
四配置
1.ip地址配置
r1：
interface GigabitEthernet0/0/0
ip address 192.168.1.1 255.255.255.252
#
interface GigabitEthernet0/0/1
ip address 192.168.1.5 255.255.255.252
#
interface LoopBack0
ip address 192.168.1.129 255.255.255.240
#
interface LoopBack1
ip address 192.168.1.145 255.255.255.240
#
r2：
#
interface GigabitEthernet0/0/0
ip address 192.168.1.2 255.255.255.252
#
interface GigabitEthernet0/0/1
ip address 192.168.1.9 255.255.255.252
#
interface GigabitEthernet0/0/2
#
interface LoopBack0
ip address 192.168.1.161 255.255.255.240
#
interface LoopBack1
ip address 192.168.1.177 255.255.255.240
#
r3：
#interface GigabitEthernet0/0/0
ip address 192.168.1.13 255.255.255.252
#
interface GigabitEthernet0/0/1
ip address 192.168.1.6 255.255.255.252
#
interface GigabitEthernet0/0/2
#
interface NULL0
#
interface LoopBack0
ip address 192.168.1.193 255.255.255.240
#
interface LoopBack1
ip address 192.168.1.209 255.255.255.240
#
r4：
interface GigabitEthernet0/0/0
ip address 192.168.1.10 255.255.255.252
#
interface GigabitEthernet0/0/1
ip address 192.168.1.14 255.255.255.252
#
interface GigabitEthernet0/0/2
ip address 192.168.1.17 255.255.255.252
#
interface GigabitEthernet4/0/0
ip address 192.168.1.21 255.255.255.252
interface LoopBack0
ip address 192.168.1.225 255.255.255.240
#
interface LoopBack1
ip address 192.168.1.241 255.255.255.240
#
r5：
#interface GigabitEthernet0/0/0
ip address 192.168.1.18 255.255.255.252
#
interface GigabitEthernet0/0/1
ip address 192.168.1.22 255.255.255.252
interface LoopBack0
ip address 5.5.5.5 255.255.255.0
2.配置静态路由，在通向r5时用缺省路由完成
r1：
ip route-static 0.0.0.0 0.0.0.0 192.168.1.2
ip route-static 0.0.0.0 0.0.0.0 192.168.1.6
ip route-static 192.168.1.8 255.255.255.252 192.168.1.2
ip route-static 192.168.1.12 255.255.255.252 192.168.1.2
ip route-static 192.168.1.16 255.255.255.252 192.168.1.2
ip route-static 192.168.1.20 255.255.255.252 192.168.1.2
ip route-static 192.168.1.160 255.255.255.224 192.168.1.2
ip route-static 192.168.1.192 255.255.255.224 192.168.1.2
ip route-static 192.168.1.224 255.255.255.224 192.168.1.2
r2：
ip route-static 0.0.0.0 0.0.0.0 192.168.1.10
ip route-static 5.5.5.0 255.255.255.240 192.168.1.10
ip route-static 192.168.1.4 255.255.255.252 192.168.1.1
ip route-static 192.168.1.12 255.255.255.252 192.168.1.10
ip route-static 192.168.1.16 255.255.255.252 192.168.1.10
ip route-static 192.168.1.20 255.255.255.252 192.168.1.10
ip route-static 192.168.1.128 255.255.255.224 192.168.1.1
ip route-static 192.168.1.192 255.255.255.224 192.168.1.1
ip route-static 192.168.1.224 255.255.255.224 192.168.1.10
r3：
ip route-static 0.0.0.0 0.0.0.0 192.168.1.14
ip route-static 5.5.5.0 255.255.255.240 192.168.1.14
ip route-static 192.168.1.0 255.255.255.252 192.168.1.5
ip route-static 192.168.1.8 255.255.255.252 192.168.1.14
ip route-static 192.168.1.16 255.255.255.252 192.168.1.14
ip route-static 192.168.1.20 255.255.255.252 192.168.1.14
ip route-static 192.168.1.128 255.255.255.224 192.168.1.5
ip route-static 192.168.1.160 255.255.255.224 192.168.1.2
ip route-static 192.168.1.224 255.255.255.224 192.168.1.14
#
r4：
ip route-static 0.0.0.0 0.0.0.0 192.168.1.18
ip route-static 0.0.0.0 0.0.0.0 192.168.1.22
ip route-static 5.5.5.0 255.255.255.240 192.168.1.18
ip route-static 5.5.5.0 255.255.255.240 192.168.1.22
ip route-static 192.168.1.0 255.255.255.252 192.168.1.9
ip route-static 192.168.1.4 255.255.255.252 192.168.1.13
ip route-static 192.168.1.128 255.255.255.224 192.168.1.9
ip route-static 192.168.1.128 255.255.255.224 192.168.1.13
ip route-static 192.168.1.160 255.255.255.224 192.168.1.9
ip route-static 192.168.1.192 255.255.255.224 192.168.1.13
r5：
ip route-static 192.168.1.0 255.255.255.252 192.168.1.17
ip route-static 192.168.1.0 255.255.255.252 192.168.1.21
ip route-static 192.168.1.4 255.255.255.252 192.168.1.17
ip route-static 192.168.1.4 255.255.255.252 192.168.1.21
ip route-static 192.168.1.8 255.255.255.252 192.168.1.17
ip route-static 192.168.1.8 255.255.255.252 192.168.1.21
ip route-static 192.168.1.12 255.255.255.252 192.168.1.17
ip route-static 192.168.1.12 255.255.255.252 192.168.1.21
ip route-static 192.168.1.128 255.255.255.224 192.168.1.7
ip route-static 192.168.1.128 255.255.255.224 192.168.1.21
ip route-static 192.168.1.160 255.255.255.224 192.168.1.7
ip route-static 192.168.1.160 255.255.255.224 192.168.1.21
ip route-static 192.168.1.192 255.255.255.224 192.168.1.17
ip route-static 192.168.1.192 255.255.255.224 192.168.1.21
ip route-static 192.168.1.224 255.255.255.224 192.168.1.17
ip route-static 192.168.1.224 255.255.255.224 192.168.1.21
#
3.r1-r4的防环
ip route-static 192.168.1.128 27 null0
ip route-static 192.168.1.160 27 null0
ip route-static 192.168.1.192 27 null0
ip route-static 192.168.1.224 27 null0
4.正常1000M链路通信，故障时自动改为100M；先用优先级低的，故障时用优先级高的一条
ip route-static 192.168.1.0 255.255.255.252 192.168.1.21 preference 61
ip route-static 192.168.1.4 255.255.255.252 192.168.1.21 preference 61
ip route-static 192.168.1.8 255.255.255.252 192.168.1.21 preference 61
ip route-static 192.168.1.12 255.255.255.252 192.168.1.21 preference 61
ip route-static 192.168.1.128 255.255.255.224 192.168.1.21 preference 61
ip route-static 192.168.1.160 255.255.255.224 192.168.1.21 preference 61
ip route-static 192.168.1.192 255.255.255.224 192.168.1.21 preference 61
ip route-static 192.168.1.224 255.255.255.224 192.168.1.21 preference 61验证：
五实验验证：
全网通：
、
俩条线路1000m故障时，另一条可用：
