R1配置：
isis 1
is-level level-2
//本区域只启用level-2级别
cost-style wide
//默认为narrow窄度量，开销只能最大63，并且不能打tag，wide宽度量的tlv和narrow不匹配，不能相互计算路由，两边都要改。
network-entity 49.0001.0000.0000.0001.00
is-name r1
//重命令后，查看lsdb时就比较直观。但查看的具体明细的时间要带上is-name，侞dis isis lsdb is-name r2.00-00 verbose
interface GigabitEthernet0/0/0
ip address 10.0.12.1 255.255.255.0
isis enable 1
isis circuit-type p2p
//改为pep链路
isis ppp-negotiation 3-way only
//强制使用3次握手，默认是2次不可靠。
interface GigabitEthernet0/0/1
ip address 10.0.13.1 255.255.255.0
isis enable 1
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
isis enable 1
r2配置：
isis 1
is-level level-2
cost-style wide
network-entity 49.0001.0000.0000.0002.00
is-name r2
interface GigabitEthernet0/0/0
ip address 10.0.12.2 255.255.255.0
isis enable 1
isis circuit-type p2p
isis ppp-negotiation 3-way only
interface GigabitEthernet0/0/1
ip address 10.0.24.2 255.255.255.0
isis enable 1
interface GigabitEthernet0/0/2
ip address 10.0.26.2 255.255.255.0
isis enable 1
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
isis enable 1
R3配置：
isis 1
cost-style wide
network-entity 49.0002.0000.0000.0003.00
is-name r3
import-route isis level-2 into level-1
//isis路由渗透，把level-2中的明细路由渗透到level-1中去
interface Serial1/0/0
link-protocol ppp
ip address 10.0.35.3 255.255.255.0
isis enable 1
isis circuit-level level-1
//由于设备使用的是默认level-1-2，此接口开启isis enable后会发level-1和level-2两种包，但2包不用，只用1，所以为了性能不发2包。
isis cost 100 level-1
//R5有两条路走，可走R3和R4，所以改去往R3和R5的接口的开销，让其它走R4一条路
isis ppp-negotiation 3-way only
interface Serial1/0/1
link-protocol ppp
interface GigabitEthernet0/0/0
ip address 10.0.13.3 255.255.255.0
isis enable 1
isis circuit-level level-2
//这个接口只连接的是level-2不用level-1的包，所以过滤掉，提高性能
interface GigabitEthernet0/0/1
ip address 10.0.34.3 255.255.255.0
isis enable 1
//R3和R4互联就用默认的level-1-2两个级别都连接，一是可以实验上面骨干区域备用互联，二是可以解决次优路径，避免R3到R4的数据包走R5绕行
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
isis enable 1
R4配置：
isis 1
cost-style wide
network-entity 49.0002.0000.0000.0004.00
is-name r4
import-route isis level-2 into level-1
//同样做路由渗透
interface GigabitEthernet0/0/0
ip address 10.0.34.4 255.255.255.0
isis enable 1
//R3和R4互联就用默认的level-1-2两个级别都连接，一是可以实验上面骨干区域备用互联，二是可以解决次优路径，避免R3到R4的数据包走R5绕行
interface GigabitEthernet0/0/1
ip address 10.0.24.4 255.255.255.0
isis enable 1
isis circuit-level level-2
//只需发level-2包
interface GigabitEthernet0/0/2
ip address 10.0.45.4 255.255.255.0
isis enable 1
isis circuit-level level-1
//只需发level-1的包
interface LoopBack0
ip address 4.4.4.4 255.255.255.255
isis enable 1
R5配置：
isis 1
is-level level-1
//本设备只需level-1
cost-style wide
network-entity 49.0002.0000.0000.0005.00
is-name r5
interface Serial1/0/0
link-protocol ppp
ip address 10.0.35.5 255.255.255.0
isis enable 1
isis cost 100 level-1
//和R3对接口子改开销为100，用于走R4上去。
isis ppp-negotiation 3-way only
interface GigabitEthernet0/0/1
ip address 10.0.45.5 255.255.255.0
isis enable 1
interface LoopBack0
ip address 5.5.5.5 255.255.255.255
isis enable 1
R6配置：
isis 1
cost-style wide
network-entity 49.0003.0000.0000.0006.00
is-name r6
interface GigabitEthernet0/0/0
ip address 10.0.26.6 255.255.255.0
isis enable 1
isis circuit-level level-2
//上联口只需开level-2，提高性能
interface GigabitEthernet0/0/1
ip address 10.0.67.6 255.255.255.0
isis enable 1
isis circuit-level level-1
//下联口只需开level-1，提高性能
interface LoopBack0
ip address 6.6.6.6 255.255.255.255
isis enable 1
R7配置：
isis 1
is-level level-1
cost-style wide
network-entity 49.0003.0000.0000.0007.00
is-name r7
import-route direct level-1
//level-1设备就和total-nssa区域原理一样，可以导入外部路由
import-route static level-1
//导入静态路由
interface GigabitEthernet0/0/0
ip address 10.0.67.7 255.255.255.0
isis enable 1
interface GigabitEthernet0/0/1
ip address 10.0.0.110 255.255.255.0
interface LoopBack0
ip address 7.7.7.7 255.255.255.255
isis enable 1
ip route-static 70.0.0.0 255.255.255.0 NULL0
//用于测试导入路由实验
查看本设备哪些口子连接了level-1设备：
伪节点查看：
p2p和广播两种链路区分，R1上查看：
在R5上看哪些是通过渗透学到的：
