When an internet connection has prefix delegation enabled, the gateway can request a prefix (in addition to an IP address) from the server and configure an internal network DHCPv6 server that uses this prefix. Connected devices are then routable without the need to use NAT.
These connection types support prefix delegation:
PPPoE-IPv6
LAN-IPv6
VLAN
Switch
Bridge
For more information, see Configuring Internet Connectivity.