Impact of hybrid queuing disciplines on the VoIP traffic delay

The paper presents different combinations of queuing methods and their impact on the VoIP traffic delay within the network. In our experiment we combined three of the most useful queuing methods where we put together priority queuing (PQ) with class-based weighted fair queuing (CBWFQ), custom queuing (CQ) with CBWFQ and weighted fair queuing (WFQ) with CBWFQ. Each hybrid method is compared with the basic method. For example, the PQ-CBWFQ method is compared with the priority queuing method, and so on. All the hybrid queuing disciplines are tested using an OPNET Modeler simulation tool. Our intention is to show the reader, how queuing combinations affect VoIP traffic quality, especially, with regard to Ethernet delay and jitter. Using results of our research-based simulations, we prove usefulness of our combination concept for Ethernet delay decreasing. Ethernet delay was rapidly decreased by using the WFQ-CBWFQ queuing combination. Though such combination (WFQ-CBWFQ) most strongly affects the jitter delay, and it is still within the set limits. Using the proposed queuing combination, it is possible to minimize the Ethernet delay for IP-based time-sensitive applications, including VoIP.