A COMPARATIVE STUDY OF IN-BAND AND OUT-OF-BAND VOIP PROTOCOLS IN LAYER 3 AND LAYER 2.5 ENVIRONMENTS

摘要: For more than a century the classic circuit-switched telephony in form of PSTN (Public Service Telephone Network) has dominated world phone communications (Varshney et al., 2002). The alternative solution VoIP (Voice over Internet Protocol) or increased dramatically its share years though. Originally started among computer enthusiasts, nowadays it become huge research area both academic community as well industry (Karapantazis and Pavlidou, 2009). Therefore, many technologies have emerged order to offer services. However, performance these is key issue for sound quality that end-users receive. When making reference still stands benchmark. Against this background, aim project evaluate different signalling protocols terms their metrics impact security packet transport mechanisms on them. In reach in-band out-ofband are reviewed along with existing techniques which protect calls network relay voice packet-switched systems. addition, various methods tools used carry out measurements examined together open source Asterisk platform. findings literature review then design implement novel experimental framework which employed evaluation out-of-band respect networks. major though lack fine-grained clock synchronisation required achieve ultra precise measurements. valid results extracted. These show highly optimised outperform certain areas. Furthermore, use specific introduces just minor overhead whereas Layer 2.5 against 3 routing does not improve protocols.