Preserving and restoring IPv6 prefixes assigned using DHCPv6 Prefix Delegation

When IPv6 addresses are assigned using DHCPv6 Prefix Delegation, you can configure the router to preserve and restore a subscriber's delegated prefix through multiple logins. This feature prevents an IA-PD change, which triggers renegotiation for all hosts attached to the residential gateway. This feature requires the use of Agent-Circuit-IDs (ACIs) to identify subscribers.