router isis
net 01.0000.ca02.1a84.001d.00
is-type level-1
---------------------------------------------------------------------------------------------
Zagreb:
interface FastEthernet1/1
ip address 172.16.4.2 255.255.255.0
ip router isis
interface Serial3/1
ip address 172.16.8.2 255.255.255.0
ip router isis
router isis
net 01.0000.ca03.8a98.001d.00
is-type level-1
---------------------------------------------------------------------------------------------
Prague:
interface Serial3/0
ip address 172.16.22.2 255.255.255.0
ip router isis
interface Serial3/1
ip address 172.16.21.2 255.255.255.0
ip router isis
interface Serial3/2
ip address 172.16.11.2 255.255.255.0
ip router isis
interface Serial3/3
ip address 172.16.10.2 255.255.255.0
ip router isis
router isis
net 01.0000.ca04.3144.001d.00
redistribute isis ip level-2 into level-1 distribute-list 100
access-list 100 permit ip 172.16.23.0 0.0.0.255 any
---------------------------------------------------------------------------------------------
Bucharest:
interface Serial3/0
ip address 172.16.5.2 255.255.255.0
ip router isis
interface Serial3/1
ip address 172.16.8.1 255.255.255.0
ip router isis
interface Serial3/2
ip address 172.16.11.1 255.255.255.0
ip router isis
interface Serial3/3
ip address 172.16.9.1 255.255.255.0
ip router isis
router isis
net 01.0000.ca05.6d7c.001d.00
---------------------------------------------------------------------------------------------
Budapest:
interface Serial3/2
ip address 172.16.10.1 255.255.255.0
ip router isis
interface Serial3/3
ip address 172.16.9.2 255.255.255.0
ip router isis
router isis
net 02.0000.ca06.84e0.001d.00
---------------------------------------------------------------------------------------------
分析：
查看Belgrade的isis数据库
图中Prague和Bucharest的ATT=1，Prague和Bucharest为L1/L2路由器
查看Belgrade的的isis路由
Belgrade到达外部区域有两条路径
在Belgrade使用traceroute172.16.23.1
在Belgrade使用扩展ping 172.16.23.1，到达172.16.23.1有两条路径，分别为Prague，Bucharest。
就拓扑来看，到达172.16.23.1的最优路由为：
Belgrade---->Prague----->Warsaw(172.16.23.1)，此时，需要使用路由泄露。
路由泄露：把L2的路由通告到L1路由器。
路由泄露配置方式：
1.创建一个包含所要通告到该区域的地址列表，使用ACL抓取地址
2.配置这个列表分发到L1路由器
Prague上的配置：
access-list 100 permit ip 172.16.23.0 0.0.0.255 any
router isis
net 01.0000.ca04.3144.001d.00
redistribute isis ip level-2 into level-1 distribute-list 100
在Belgrade上traceroute
泄露到L1的路由在路由表中会有ia的标识，观察Belgrade的路由表
在Belgrade的isis数据库中泄露的地址会有IP-Interarea标识
