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