The revolutionary advances in the wireless communication technologies are inspiring the researchers to envision the next generation wireless networking architectures, i.e., Next Generation Wireless Internet (NGWI), InterPlaNetary (IPN) Internet, and Wireless Sensor Networks (WSN). There exist significant technological challenges for the realization of these envisioned next generation network architectures. NGWI will be the convergence of the Internet and heterogeneous wireless architectures, which have diverse characteristics and hence pose different sets of research challenges, to achieve anywhere, anytime seamless service to the mobile users. Similarly, the unique characteristics and challenges posed by deep space communications call for novel networking protocols to realize the IPN Internet objective. Furthermore, in order to realize the potential gains of WSN, it is imperative that communication challenges imposed by resource constraints of sensor nodes must be efficiently addressed with novel solutions tailored to the WSN paradigm. The objective of this research is to develop new advanced transport protocols for reliable data transport and real-time multimedia delivery in the next generation heterogeneous wireless network architectures. More specifically, the analytical rate control (ARC) protocol for real-time multimedia delivery is first proposed for wired/wireless hybrid networks. Next, a new rate control scheme (RCS) is proposed to achieve high throughput performance and fairness for real-time multimedia traffic over the satellite links. The unified adaptive transport layer (ATL) suite and its protocols for both reliable data transport (TCP-ATL) and real-time multimedia delivery (RCP-ATL) are introduced for the NGWI. A new reliable transport protocol for data transport in the IPN Internet (TP-Planet) is then proposed to address the unique challenges of the IPN Internet backbone links. A new integrated tranmission protocol (ITP) is then proposed for reliable data transport over multihop IPN Internet paths. Finally, the event-to-sink reliable transport (ESRT) protocol is proposed to achieve reliable event transport with minimum energy expenditure in WSN.