Key benefits of active gateway compared to VRRP
Configuration overhead: For VRRP, you must configure the VRIDs on per VLAN basis and designate their priorities. Then, you must decide if you have to use an Interface IP address as master IP or configure a new backup IP address.
With an active gateway, the configuration overhead is simplified. Only the configuration of a virtual IP and a virtual MAC on an interface VLAN is required.
Protocol overhead: With VRRP, the primary VRRP router keeps sending advertisements every second to the backups, which result in a VLAN flood that goes to all nodes in the subnet. The sending of these advertisements helps the backup VRRP router know that the primary VRRP router is still alive.
With active gateway, there is no protocol advertisement as the configurations are static. Active gateway is active-active so each device does not have to know if the peer device is active from an active gateway perspective.
Datapath: VRRP is an active-standby protocol. If the backup VRRP router receives traffic that must be routed across to the other subnets, the VRRP router bridges it to the primary VRRP router. The primary VRRP router then does the actual forwarding.
With an active gateway, both devices are ready to forward layer 3 traffic to the other subnets individually. This method avoids the extra bridged hop from the backup to the primary VRRP router.