H3C Technologies H3C SecPath F1000-E - Manual (Page 81)

2
1. The DHCPv6 client sends out a Solicit message that contains a Rapid Commit option, requesting
that rapid assignment of address/prefix and other configuration parameters should be preferred.
2. If the DHCPv6 server supports rapid assignment, it responds with a Reply message containing the
assigned IPv6 address/prefix and other configuration parameters. If the DHCPv6 server does not
support rapid assignment,
Assignment Involving Four Messages is implemented.
Assignment Involving Four Messages
Figure 2 shows the process of IPv6 address/prefix assignment involving four messages.
Figure 2 Assignment involving four messages
The process of assignment involving four messages is 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 the DHCPv6 server does not
support rapid assignment though a Rapid Commit option is contained, 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.
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 use the IPv6 address/prefix longer, the DHCPv6 client has to renew
the lease time.