1，拓扑图
2，
R1
ip sla 1 icmp-echo 12.1.1.2 source-ip 12.1.1.1 frequency 5 ip sla schedule 1 life forever start-time now
track 8 ip sla 1 reachability
ip route 4.4.4.4 255.255.255.255 12.1.1.2 track 8 ip route 4.4.4.4 255.255.255.255 13.1.1.3 10
原文：https://www.cnblogs.com/xiaomai-rhce/p/13576338.html