Volume 11, Number 5

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


Shaher Daoud and Yanzhen Qu, Colorado Technical University, USA


Various factors can have a significant degrading impact on the residential Voice over Internet Protocol (VoIP) phone services’ quality. Hybrid fibre- coaxial (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. This paper will analyze and assess VoIP traffic prioritization and its impact on VoIP’s quality of service (QoS) based on the concept of differentiated services code point (DSCP) markings. Call testing examines two types of calls. The first set of tests focus on calls that originate from a VoIP network and terminate on a signalling system 7 (SS7) network. The second experiment focuses on calls that originate from SS7 network and terminate on a VoIP network. The research results provide DSCP markings configurations that can improve phone conversations’ quality.


QoS , VoIP, DSCP Marking , jitter, HFC Network, MOS.