VLAN aggregation is a very specific application, and the following properties apply to its operation:
All broadcast and unknown traffic remains local to the subVLAN and does not cross the subVLAN boundary. All traffic within the subVLAN is switched by the subVLAN, allowing traffic separation between subVLANs (while using the same default router address among the subVLANs).
Hosts can be located on the superVLAN or on subVLANs. Each host can assume any IP address within the address range of the superVLAN router interface. Hosts on the subVLAN are expected to have the same network mask as the superVLAN and have their default router set to the IP address of the superVLAN.
All IP unicast traffic between subVLANs is routed through the superVLAN. For example, no ICMP redirects are generated for traffic between subVLANs, because the superVLAN is responsible for subVLAN routing. Unicast IP traffic across the subVLANs is facilitated by the automatic addition of an ARP entry (similar to a proxy ARP entry) when a subVLAN is added to a superVLAN. This feature can be disabled for security purposes.