However this is not always the case,
so in order to be sure there is no collision it uses ICMPv6’s
Duplicate Address Detection, which asks to the nodes on the
network if this address already exists using a Neighbor
Solicitation packet. If it does exist, it stops the autoconfiguration
and needs manual configuration, otherwise it
uses this address. For global addresses it uses the network
prefix the router advertised to the machine instead of the linklocal
prefix. This process has been depicted in figure 1.