F3726, F3211, F3174, R5135, R3816-HP Firewalls and UTM Devices Network Management Configuration Guide-6PW100

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Figure 365 Rapid assignment involving two messages
849BAssignment involving four messages
2887HFigure 366 shows the process of IPv6 address/prefix assignment involving four messages.
Figure 366 Assignment involving four messages
The assignment involving four messages operates as follows:
1. The DHCPv6 client sends out a Solicit message, requesting an IPv6 address/prefix and other
configuration parameters.
2. If the Solicit message does not contain a Rapid Commit option, or if the DHCPv6 server does not
support rapid assignment even though the Solicit message contains a Rapid Commit option, the
DHCPv6 server responds with an Advertise message, informing the DHCPv6 client of the
assignable address/prefix and other configuration parameters.
3. The DHCPv6 client may receive multiple Advertise messages offered by different DHCPv6 servers.
It then selects an offer according to the receiving sequence and server priority, and sends a
Request message to the selected server for the confirmation of assignment.
4. The DHCPv6 server sends a Reply message to the client, confirming that the address/prefix and
other configuration parameters are assigned to the client.
231B
Address/prefix lease renewal
The IPv6 address/prefix assigned by the DHCPv6 server has a lease time, which depends on the valid
lifetime. When the valid lifetime of the IPv6 address/prefix expires, the DHCPv6 client cannot use the
IPv6 address/prefix any longer. To continue using the IPv6 address/prefix, the DHCPv6 client has to
renew the lease time.
As shown in
2888HFigure 367, at T1, the DHCPv6 client sends a Renew message to the DHCPv6 server. The
recommended value of T1 is half the preferred lifetime. Then the DHCPv6 server responds with a Reply
message, informing the client about whether or not the lease is renewed.