This paper presents two approaches to efficient service development for Internet Telephony. In first approach we consider services ranging from core call signaling features and media control as stated in ITU-T's H.323 to end user services that supports user interaction. The second approach supports IETF's SIP protocol. We compare these from differing architectural perspectives, economy of network and terminal development, and propose efficient architecture models for both protocols. In their design, the main criteria were component independence, lightweight operation and portability in heterogeneous end-to-end environments. In proposed architecture, the vertical division of call signaling and streaming media control logic allows for using the components either individually or combined, depending on the level of functionality required by an application.