FRR（Fast Reroute，快速重路由） 旨在当网络中链路或者节点失效后，为这些重要的节点或链路提供备份保护，实现快速重路由，减少链路或节点失效时对流量的影响，使流量实现快速恢复。
1、核心知识
1、为重要节点或链路提供备份保护
2、核心节点配置
1）ospf 100
FRR
loop-free-alternate
2、核心设备配置
<r1>display current-configuration
[V200R003C00]
#
sysname r1
#
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
#
firewall zone Local
priority 15
#
interface GigabitEthernet0/0/0
ip address 10.1.1.1 255.255.255.0
ospf cost 5
#
interface GigabitEthernet0/0/1
ip address 20.1.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/2
#
interface NULL0
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ospf 100 router-id 1.1.1.1
frr
loop-free-alternate
area 0.0.0.0
network 10.1.1.0 0.0.0.255
network 20.1.1.0 0.0.0.255
#
user-interface con 0
authentication-mode password
idle-timeout 0 0
user-interface vty 0 4
user-interface vty 16 20
#
wlan ac
#
return
<r1>
测试结果
