They specify the prefix information included in the RA message to hosts for 
generating their IPv6 address. 
They specify the Advertisement Valid Lifetime and Advertisement Preferred Lifetime. 
When the preferred lifetime expires, the use of the prefix is not encouraged, but not 
prohibited. When the valid lifetime expires, the prefix becomes invalid. 
 
The valid lifetime must be greater than or equal to the preferred lifetime. 
It specifies whether the router advertisement is on the link. 
It specifies whether the prefix in the router advertisement can be used to generate 
IPv6 address. 
They specify the Recursive DNS Server (RDNSS) addresses assigned to IPv6 hosts for 
DNS information configuration. 
It specifies whether to enable the Unique Local Address (ULA). 
The purpose of ULA resembles that of the private network address in IPv4. It is only 
used within the private network and increases stability for the IPv6 host and its use of 
services. 
They specify the ULA prefix information advertised by the ONT to hosts for generating 
unique local addresses. 
ULA Prefix Valid 
Lifetime 
They specify the valid lifetime and preferred lifetime of ULA prefix. 
When the preferred lifetime expires, the use of the ULA prefix is not encouraged, but 
not prohibited. When the valid lifetime expires, the ULA prefix becomes invalid. 
 
The valid lifetime must be greater than or equal to the preferred lifetime. 
ULA Prefix Preferred 
Lifetime 
9.2.3  DHCPv6 
IPv6 hosts may automatically generate IP addresses internally using Stateless Address 
Autoconfiguration (SLAAC), or they may be assigned configuration with Dynamic Host 
Configuration Protocol version 6 (DHCPv6). When the DHCPv6 server is enabled, the ONT can 
assign IPv6 hosts with IP addresses, IP prefixes and other configurations required for IPv6 internet 
access. 
To access the page, log in to the web UI of the ONT and choose Advance > IPv6 > DHCPv6.