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Figure 50 Assignment involving four messages
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 51 Using the Renew message for address/prefix lease renewal
As shown in
, 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 52 Using the Rebind message for address/prefix lease renewal
As shown in
:
•
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 IPv6 basics configuration
in
Layer 3—IP Services Configuration Guide
.
