One major pattern of cultural interaction between Nomadic and Sedentary societies in Afro Eurasia before 1450 CE is Expansion and intensification of Communication and Exchange Networks . The results were unprecedented concentrations of wealth and the intensification of cross-cultural exchanges. Innovations in transportation, state policies, and mercantile practices contributed to the expansion and development of commercial networks, which in turn served as conduits for cultural, technological, and biological diffusion within and between various societies.Pastoral or nomadic groups played a key role in creating and sustaining these networks.Expanding networks fostered greater interregional exchanges while at the same time sustaining regional diversity.A deepening and widening of networks of human interaction within and across regions contributed to cultural, technological, and biological diffusion within and between various societies.