Renumbering

Precondition
All IPv6 nodes have address auto-configuration
Each IPv6 node can obtain multiple IPv6 addresses
IPv6 addresses have two timers
preferred lifetime and valid lifetime
Renumbering procedure:
An old address

(A new prefix is announced)
A new address, the old address

(The first timer is expired)
<The old address is not used as a source address>

(The second timer is expired)
The new address