Optimizing DSCP Marking to Ensure VoIP’s QoS over HFC Network

Abstract

Three major factors that can affect Voice over Internet Protocol (VoIP) phone services' quality, these include packet delay, packet loss, and jitter. The focus of this study is specific to the VoIP phone services offered to customers by cable companies that utilize broadband hybrid fiber coaxial (HFC) networks. HFC networks typically carry three types of traffic that include voice, data, and video. Unlike data and video, some delays or packet loss can result in a noticeable degraded impact on a VoIP's phone conversation. We will examine various differentiated services code point (DSCP) marking, then analyze and assess their impact on VoIP's quality of service (QoS). This study mimics the production environment. It examines the relationship between specific DSCP marking's configuration. This research avoids automated test calls and rather focuses on human made call testing. This study relies on users' experience and the captured data to support this research's findings.

A Comprehensive Study of Dscp Markings’ Impact on Voip Qos in Hfc Networks

“…The highest packet loss is 0.27%, and the highest latency value is 54 ms. Examining the values of each of the dependent variables under Table 2 indicates that each of the values was within specifications which lead to good and clear phone conversations between both parties [1,2].…”

“…Packet loss is 0%, and there is no indication of any latency. Examining the values of each of the dependent variables under Table 11 indicate that each of the values was within specifications that lead to good and clear phone calls between both parties [1,2]. Figure 4 illustrates the mean values of latencies for each of the 10 test cases.…”

“…The mean value for the interpacket arrival time associated with each of the 10 test cases is 20 ms. This value goes hand-in-hand with the VoIP standards of good interpacket arrival time of 20 ms[1,2].…”

“…The lowest mean value for MOS is 4.392 which belong to the CS0 marking of the SS7 based manual test calls.This value refers to a good quality VoIP phone conversation. According to VoIP standards; any MOS value between 4 and 5 indicates a good quality phone conversation[1,2].…”

A Comprehensive Study of DSCP Markings’ Impact on VOIP QoS in HFC Networks

“…This research may benefit the different VoIP carriers to improve the quality of their VoIP traffic offered to their subscribers. Carriers can request and negotiate with other carriers in the telecommunications industry to prioritize their carried VoIP traffic [1,2].…”