1、实验拓扑图
2、实验目的
R1、R2、R3之间构建LEVEL-1关系，R3、R4、R5之间构建LEVEL-S关系，R3为LEVEL-1-2路由器（边界路由器）；默认情况下，R3产生ATT置位为1的LSP，另LEVEL-1路由器收到ATT为1的LSP后产生下一跳指向R3的缺省路由；之后再验证对ATT比特位进行手动配置产生的后续结果
3、配置
[r3]display current-configuration
[V200R003C00]
#
sysname r3
#
snmp-agent local-engineid 800007DB03000000000000
snmp-agent
#
clock timezone China-Standard-Time minus 08:00:00
#
portal local-server load flash:/portalpage.zip
#
drop illegal-mac alarm
#
wlan ac-global carrier id other ac id 0
#
set cpu-usage threshold 80 restore 75
#
aaa
authentication-scheme default
authorization-scheme default
accounting-scheme default
domain default
domain default_admin
local-user admin password cipher %$%$K8m.Nt84DZ}e#<0`8bmE3Uw}%$%$
local-user admin service-type http
#
isis 100
cost-style wide
network-entity 49.0001.0030.0300.3003.00
//LEVEL-1必须是同一个area
#
firewall zone Local
priority 15
#
interface GigabitEthernet0/0/0
ip address 20.1.1.2 255.255.255.0
isis enable 100
#
interface GigabitEthernet0/0/1
ip address 30.1.1.1 255.255.255.0
isis enable 100
#
interface GigabitEthernet0/0/2
#
interface NULL0
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
#
user-interface con 0
authentication-mode password
idle-timeout 0 0
user-interface vty 0 4
user-interface vty 16 20
#
wlan ac
#
return
[r3]
4、实验结果
ATT默认值为1，会为level-1区域添加默认路由
5、修改参数
isis 1
attached-bit advertise never
#配置 IS-IS LSP 报文的 ATT比特位置位规则为永不置位
isis 1
import-route isis level-2 into level-1
