Heartbeats depends, if is the server do when HA heartbeat have 2 root, because the server can't VRRP protocol, a piece of cable is used to check whether the main equipment, detection means such as ping, another line is the line of RS232 or 485 is used to control the main equipment in the problems make it shut down, to prevent the master half-dead business affected, if used in the network, such as the image below in the firewall, the firewall if two downstream equipment for passthrough (similar to the 2 firewall under a single switch), can need not heartbeats, message VRRP interaction, through the bottom allied switches used to examine the main equipment is live, and if bottom allied equipment for multiple switch equipment, just need to add a line separately for exchange of VRRP packet, check whether the master device is alive,