Combinaçao de pilhas de protocolo para a construçao de um softphone SIP

Through the identification of requirements to be matched by a protocol stack in order to implement a VoIP application, many SIP stacks are studied, analyzed and compared. Arguments in favor of using ReSIProcate and OpenSIPStack libraries to implement a SIP softphone are detailed. An API is constructed to integrate both stacks and allow easy and modular application programming. Softphone programming procedures using this API are discussed.