next level aggregation (IPv6) (NLA)
Next Level Aggregation (NLA) is a 24-bitdata field in the IPv6 header. The NLA data field originally consisted of an 8-bit reserved data field( RES) intended for longer top- level domains(TLDs).
Next Level Aggregation identifies the second level within the addressing space of IPv6 and follows the Top Level Aggregation( TLA) data field. Due to the division of the address space into Top Level Aggregation (TLA), Next Level Aggregation (NLA) and Site Level Aggregation( SLA), the IPv6 protocol 's routingeffort is limited to the relevant address part in the respective level aggregation.