The popularity of the internet has led to a very rapid growth of IPv4 (Internet Protocol v4) users. This caused a shortage of IP addresses, so it was created a new version – IPv6 (Internet Protocol v6). Currently, there are two versions of IP for IPv4 and IPv6. Due to the large differences in addressing the protocols IPv4 and IPv6 are incompatible. It is therefore necessary to find ways to move from IPv4 to IPv6. To facilitate the transition from one version to another are developed various mechanisms and strategies. Comparative analysis is done for dual stack, 6to4 tunnel and NAT64 mechanisms in this work. It has helped to reveal the shortcomings of these mechanisms and their application in selection of realization decisions.