[Boost-users] iostreams or sockets?

hi, in the asio examples there are two daytime examples , one use iostreams and the other one sockets, what criteria do i have to follows to choose one or the other? i've not really clear this concept? thanks -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain