How Gateway redundancy works (Summary)
VRRP (virtual router redundancy protocol) is an industry standard gateway redundancy protocol, while HSRP (hot standby router protocol) and GLBP (gateway load balance protocol) are CISCO proprietary protocols.
Set the same virtual IP address on two or more gateway devices (and they each have a physical interface IP address), and the gateway of the end host points to this virtual IP address. The primary and standby gateway devices are specified by setting priority. Under normal circumstances, network traffic goes to the primary gateway device, and when the primary gateway device fails, it goes to the standby gateway device.
