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Ross Chandler
Between the options of dynamic and static there is also the possibility of dynamic but sticky DHCPv6 PD leases. With sticky leases the DHCP server remembers the client had a lease for a configurable longer period after the expiration of the valid-lifetime that is advertised to CPE DHCP server. Normally the sticky lease will be deleted if the DHCP client sends a release message. For even greater stickiness it can be possible to ignore these releases. If the PD changes the CPE needs to follow RFC 7084 L-13 for the old prefix.