Bandung, Y., Machbub, C., R. Langi, A. Z. and Supangkat, S. H. (2013) “Optimizing Low Speed VoIP Network for Rural Next Generation Network (R-NGN)”, Journal of ICT Research and Applications, 1(2), pp. 117-131. doi: 10.5614/itbj.ict.2007.1.2.4.