(1)拓扑图
2）需求：
-实现PC1和PC2的通信
3）配置步骤：
-配置接口IP地址
-开启ISIS---类似于在OSPF中创建进程
-配置NET地址---类似于在OSPF中创建区域，指定Router-id
-在接口上启用ISIS--类似于在OSPFv2中用network 宣告
-验证邻居是否建立成功
[R1]isis 1
[R1-isis-1]network-entity 49.0010.0000.0000.0001.00
[R1]int g0/0/0
[R1-GigabitEthernet0/0/0]ip add 192.168.10.1 24
[R1-GigabitEthernet0/0/0]isis enable 1
[R1]int g0/0/1
[R1-GigabitEthernet0/0/1]ip add 192.168.1.254 24
[R1-GigabitEthernet0/0/1]isis enable 1
[R2]isis 1
[R2-isis-1]network-entity 49.0010.0000.0000.0002.00
[R2]int g0/0/0
[R2-GigabitEthernet0/0/0]ip add 192.168.10.2 24
[R2-GigabitEthernet0/0/0]isis enable 1
[R2]int g0/0/1
[R2-GigabitEthernet0/0/1]ip add 192.168.20.2 24
[R2-GigabitEthernet0/0/1]isis enable 1
[R3]isis 1
[R3-isis-1]network-entity 49.0020.0000.0000.0003.00
[R3]int g0/0/0
[R3-GigabitEthernet0/0/0]ip add 192.168.20.3 24
[R3-GigabitEthernet0/0/0]isis enable 1
[R3]int g0/0/1
[R3-GigabitEthernet0/0/1]ip add 192.168.30.3 24
[R3-GigabitEthernet0/0/1]isis enable 1
[R4]isis 1
[R4-isis-1]network-entity 49.0020.0000.0000.0004.00
[R4]int g0/0/0
[R4-GigabitEthernet0/0/0]ip add 192.168.30.4 24
[R4-GigabitEthernet0/0/0]isis enable 1
[R4]int g0/0/1
[R4-GigabitEthernet0/0/1]ip add 192.168.2.254 24
[R4-GigabitEthernet0/0/1]isis enable 1
4）验证：
-配置ISIS后，通过验证，PC1可以与PC2通信
-有L1和L2的邻居关系
-有L1和L2的链路状态数据库
-有L1和L2的路由条目
