Avoiding Voice Traffic Degradation in IP Enterprise Networks Using CAoS
Paulo D S Maribondo, Natalia Castro Fernandes · 2016
In this paper we propose a new method for Codec Adaptation Over Software-defined networks: CAoS. This is based on a software-defined network architecture and implements an efficient and innovator approach for voice degradation avoidance in enterprise networks. Enterprise scarce WAN links queue voice traffic and also limit it to a certain number of calls by performing QoS and CAC on border elements. This study proposes the use of an existing centralized SDN controller to monitor real-time voice traffic and to avoid voice congestion. We implement a codec adaptation to VoIP peers that are competing for scarce throughput. Differently from other approaches, a SDN-based network already counts on a centralized controller, which can perform other type of features, like CAoS, without adding any other hardware to the network, optimizing company CAPEX. Emulation tests were performed using Mininet, POX controller and programmable VoIP clients. CAoS module was added to the software-based controller and it was divided in two sub-modules: monitoring and decision modules. Programmable VoIP clients received a third module, called SIP module, which is responsible for effectively updating the codec in use. The results show that quality of voice increases significantly when congestion occurs in a link and CAoS is running.