[RT2-isis-1]network-entity 10.0001.0001.0001.00 [RT2-isis-1]is-level level-1 [RT2-isis-1]quit
[RT2]interface LoopBack 1 [RT2-LoopBack1]isis enable
[RT2-LoopBack1]isis circuit-level level-1 [RT2-LoopBack1]quit [RT2]interface Serial 0/2/2 [RT2-Serial0/2/2]isis enable
[RT2-Serial0/2/2]isis circuit-level level-1 [RT2-Serial0/2/2]quit RT3路由器配置： [H3C]sysname RT3 [RT3]interface s0/2/0
[RT3-Serial0/2/0]ip address 10.1.1.2 24 [RT3-Serial0/2/0]quit [RT3]interface Serial 0/2/2
[RT3-Serial0/2/2]ip address 20.1.1.1 24 [RT3-Serial0/2/2]quit [RT3]isis
[RT3-isis-1]network-entity [RT3-isis-1]is-level level-1-2
10.0002.0002.0002.00
[RT3-isis-1]quit [RT3]
[RT3]interface Serial 0/2/0 [RT3-Serial0/2/0]isis enable
[RT3-Serial0/2/0]isis circuit-level level-1 [RT3-Serial0/2/0]quit [RT3]interface Serial 0/2/2 [RT3-Serial0/2/2]isis enable
[RT3-Serial0/2/2]isis circuit-level level-2 [RT3-Serial0/2/2]quit RT4路由器配置如下： [H3C]sysname RT4
[RT4]interface Serial 0/2/0
[RT4-Serial0/2/0]ip address 20.1.1.2 24 [RT4-Serial0/2/0]quit [RT4]interface LoopBack 1
[RT4-LoopBack1]ip address 4.4.4.4 32 [RT4-LoopBack1]quit [RT4]isis
[RT4-isis-1]network-entity 20.0003.0003.0003.0003.00 [RT4-isis-1]is-level level-2 [RT4-isis-1]quit
[RT4]interface Serial 0/2/0 [RT4-Serial0/2/0]
[RT4-Serial0/2/0]isis enable
[RT4-Serial0/2/0]isis circuit-level level-2 [RT4-Serial0/2/0]quit [RT4]interface LoopBack 1 [RT4-LoopBack1]isis enable
[RT4-LoopBack1]isis circuit-level level-2 [RT4-LoopBack1]quit [RT4]
配置好了之后查看RT4的路由表，发现可以学到RT2和RT3上的路由： [RT4]display ip routing-table Routing Tables: Public
Destinations : 8 Routes : 8
Destination/Mask Proto Pre Cost NextHop Interface
2.2.2.2/32 ISIS 15 20 20.1.1.1 S0/2/0
4.4.4.4/32 Direct 0 0 127.0.0.1 InLoop0
10.1.1.0/24 ISIS 15 20 20.1.1.1 S0/2/0
20.1.1.0/24 Direct 0 0 20.1.1.2 S0/2/0
20.1.1.1/32 Direct 0 0 20.1.1.1 S0/2/0
20.1.1.2/32 Direct 0 0 127.0.0.1 InLoop0
127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0
127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0
7. 路由策略和路由引入：
如图所示，三台路由器，RT2和RT3上配置了OSPF，RT3和RT4上配置了ISIS。在ISIS的RT4上宣告192.168.0.1和192.168.1.1。这时路由器RT3上可以学习到这两个网段，RT2因为配置的是
OSPF，所以学习不到这个网段，配置路由引入，把OSPF网段引入给ISIS，把ISIS网段引入给OSPF。在把ISIS引入到OSPF的时候更改引入的两个路由信息的cost值，改成20。 路由引入的配置如下： RT2的配置： [H3C]sysname RT2
[RT2]interface LoopBack 1
[RT2-LoopBack1]ip address 2.2.2.2 32 [RT2-LoopBack1]quit [RT2]interface Serial 0/2/2
[RT2-Serial0/2/2]ip address 10.1.1.1 24 [RT2-Serial0/2/2]quit [RT2]ospf router-id 2.2.2.2 [RT2-ospf-1]area 0
[RT2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0 [RT2-ospf-1-area-0.0.0.0]network 10.1.1.0 0.0.0.255 [RT2-ospf-1-area-0.0.0.0]quit [RT2-ospf-1]quit [RT2]
RT3路由器配置如下： [H3C]sysname RT3
[RT3]interface Serial 0/2/0