With the popularization of the wireless and wired networks, this paper will regard WiFi, WiMAX and CATV (DOCSIS) as the research objects, focus on the relevant technology of seamless layer 2 framework for heterogeneous networks. Seamless communication is the most important topic of this paper, beside it, routing cost and QoS guarantees, will also be important problems that must be considered in the future. This paper will combine Wi-Fi, WiMAX and DOCSIS into family's heterogeneous networks, and propose the seamless integration mechanism named Seamless Residential Gateway (SRG). SRG can offer formats and QoS mapping of heterogeneous networks, to promote and improve the connection quality of family's heterogeneous networks at present.