AFTR is a segment in the ISP’s core network. From the B4 AFTR conclude the IPv6 tunnel. The IPv6 burrow is framed between B4 for the supporter reason. An AFTR is an ISP device to remove IPv4-in-IPv6 tunnel data from packets. AFTR remove IPv6 packets getting from B4 to recover the subscribers’ original IPv4 packets. It transfers the IPv4 packets to the LSN component. LSN routes IPv4 packets, performing port translation and sending them to destiny. Then AFTR utilizes its AFTR tunnel endpoint address to IPv6 source and gets IPv6 from B4.