Performance Evaluation of the QoS for VoIP using Different CODECS

Abstract

Voice over Internet Protocol (VoIP) service is growing very fast and supported by many applications. Its interactive nature makes it very attractive service. VoIP requires a precise level of quality to be utilized. Quality of Service (QoS) is determined by factors like jitter, traffic sent, traffic received and end-to-end delay. In this paper, we study the performance of different scheduling schemes, like: FIFO, PQ, and WFQ for different codec formats. The implementation of the schemes was carried out using OPNET. VoIP service is deployed using the internet implementing the Resource Reservation Protocol ( I. INTRODUCTIONNowadays, very huge amounts of voice traffic are transferred between millions of people across the world using different social media applications. Using VoIP over the Internet connection, we should be aware about the quality of the VoIP service. VoIP service requires a precise level of quality to be utilized. The end user perception of the quality is determined by subjective testing as a function of the network impairments such as delay, jitter, packet loss, and blocking probability. The amount of impairment introduced by a packet network depends on the particular QoS mechanism implemented [1] Quality of Service (QoS) is determined by factors like the delay the packet delay variation (jitter), and the data loss rate [2]. The greatest technical problem in supporting multimedia services over IP is that real-time traffic must reach its destination within a preset time interval (delay) and with some tolerance of the delay variation (jitter). This is difficult because the original UDP/IP operates on a best-effort basis and permits dropping of packets on the way to a destination [3]. The simulation model was done using OPNET Modeler [4] [5]. OPNET has gained considerable popularity in academia as it is being offered free of charge to academic institutions. That has given OPNET an edge over DES NS2 in both market place and academia [6]. In this paper, we studied the performance of the most popular scheduling schemes, like: First-In First-Out (FIFO), priority Queuing (PQ), and Weighted Fair Queuing (WFQ). A comparison is carried out between different codecs (G.711, G.729A and G.723.15) which are the most appropriate to improve QoS for VoIP. The rest of the paper is organized as follows. Section II presents a typical WAN network topology that uses RSVP protocol to be used as a case study for deploying VoIP service. Section III describes the VoIP service and its parameters. Section IV presents the OPNET-based simulation approach for deploying VoIP service. Section V describes the results and analysis of the simulation study. Then section VI conclusion.

Performance Analysis of G.711 and G.729 Codec Schemes under Various Queuing Techniques in Voice over Internet Protocol Transmissions

“…A wired Local Area Network with multiple traffic types was designed in [17] focusing on enhancing network performance and Quality of Service (QoS), performance metrics like average end-to-end delay, jitter and traffic received were compared under three queuing techniques namely; FIFO, PQ and WFQ. WFQ and PQ are seen to have the highest amount of VoIP traffic received with FIFO having the lowest amount.…”

“…The same amount of voice traffic was received in CQ, PQ, and WFQ while FIFO received less. . 9 is an extract from the results of [17] showing the average end-to-end delay experienced by different codec schemes as the number of VoIP connections in a LAN was increased. This was done using NS-2 simulation tool and did not consider queuing techniques.…”

“…Figure. 9 is an extract from the results of [17] showing the average end-to-end delay experien schemes as the number of VoIP connections in a LAN was increased. This was done using NS-2 not consider queuing techniques.…”