Abstract: The problem of interconnecting and communicating between IPv4 network and IPv6 network in need to be solved while transiting from IPv4 to IPv6. To connect IPv4 islands through IPv6 network, an IPv4 over IPv6 tunnel solution based on User Datagram Protocol (UDP) called BoIP is proposed. BoIP uses high bandwidth of IPv6 and runs simply and low-costly. Working processes and implementation are described. Experiment results on the test-bed show that BoIP can transparently connect two IPv4 networks through IPv6 network.