BFD

1.BFD

配置双向转发检测(Bidirectional Forwarding Deteletion，BFD)实现链路故障快速检测和静态路由的自动切换。

以R3为例配置R3和R2之间的BFD会话
[R3]BFD //配置BFD
[R3-bfd] quit 
[R3]bfd 1 bind peer-ip 10.23.0.1 source-ip 10.23.0.3 auto //配置R3和R2之间的BFD会话
[R3-bfd-session-1]commit //提交配需
[R3-bfd-session-1]quit 

\\配置去往服务器网段的浮动静态路由，优先选择经R1路由器转发，而将经R3路由器转发作为备份链路
[R2]ip route-static 10.2.2.0 0.255.255.255 10.12.0.1 
[R2]ip route-static 10.2.2.0 0.255.255.255 10.23.0.3 preference 100 

\\
[R1] ip route-static 0.0.0.0 0.0.0.0 GigabitEthemet2/0/1 10.12.12.2 track bfd-session R1 to R2 //配置R1的缺省路由，联动BFD使得R1到2的流量优先走R1->S1->R2链路，当此链路发生故障时、流量切换到R1->R3->R2链路上
[R1] ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet2/0/2 10.13.13.3 preference 100 //该条命令的作用(5)