A system and method for use at an intermediate network device employs Virtual Local Area Network (VLAN) designations as Internet Protocol version 6 (IPv6) link identifiers, and maps VLAN designations to IPv6 site identifiers (IDs). The system also generates a compacted look-up address based on the destination address specified within a received network message, such as an IPv6 packet. For a network message having a link-local unicast destination address, the VLAN ID associated with the port on which the message was received is encoded within the corresponding look-up address. For a network message having a site-local unicast address, the VLAN ID associated with the port on which the message was received is used to derive a site ID which is then encoded within the corresponding look-up address. For a network message having a multicast destination address, if the address's scope value is between hexadecimal "2" and "4" inclusive, the VLAN ID associated with the port on which the message was received is encoded within the corresponding look-up address. If the scope value is between hexadecimal "5" and "D", inclusive, the VLAN ID associated with the port on which the message was received is used to derive a site ID which is then encoded within the corresponding look-up address. The look-up addresses are applied to a forwarding information base (FIB) to derive the outbound interface(s) from which the message is to be forwarded.