i'm running ip sla for isp failover/failback on an isr 1900 with below configuration:
track 1 ip sla 1 reachability
delay down 180
ip sla 1
icmp-echo 184.108.40.206 source-interface FastEthernet0/0
ip sla schedule 1 life forever start-time now
When i do a cable pull test(pulling cable from isp1 interface and put back)failover/failback works fine. Sometimes, during actual outages, it fails over fine but does not failback. Does running icmp-echo instead of another method effect this? Is it better to make the icmp target the isp modem instead of a dns server on the internet?