Address/prefix lease renewal
An IPv6 address/prefix assigned by a DHCPv6 server has a valid lifetime. After the valid lifetime expires, the DHCPv6 client cannot use the IPv6 address/prefix. To use the IPv6 address/prefix, the DHCPv6 client must renew the lease time.
Figure 64: Using the Renew message for address/prefix lease renewal
As shown in Figure 64, at T1, the DHCPv6 client sends a Renew message to the DHCPv6 server. The recommended value of T1 is half the preferred lifetime. The DHCPv6 server responds with a Reply message, informing the client whether the lease is renewed.
Figure 65: Using the Rebind message for address/prefix lease renewal
As shown in Figure 65:
If the DHCPv6 client does not receive a response from the DHCPv6 server after sending a Renew message at T1, it multicasts a Rebind message to all DHCPv6 servers at T2. Typically, the value of T2 is 0.8 times the preferred lifetime.
The DHCPv6 server responds with a Reply message, informing the client whether the lease is renewed.
If the DHCPv6 client does not receive a response from any DHCPv6 server before the valid lifetime expires, the client stops using the address/prefix.
For more information about the valid lifetime and the preferred lifetime, see "Configuring basic IPv6 settings."