Performance evaluation of legacy QCN for multicast and multiple unicast traffic transmission

Abstract

A multicast congestion control scheme is an interesting feature to control group communication applications such as teleconferencing tools and information dissemination services. This paper addresses a comparison between multiple unicast and multicast traffic congestion control for Carrier Ethernet. In this work, we proposed to study the Quantized Congestion Notification (QCN), which is a Layer 2 congestion control scheme, in the case of multicast traffic and multiple unicast traffic. Indeed, the QCN has recently been standardized as the IEEE 802.1Qau Ethernet Congestion Notification standard. This scheme is evaluated through simulation experiments, which are implemented by the OMNeT++ framework. This paper evaluates the Reaction Point (RP) start time congestion detection, feedback rate, loss rate, stability, fairness and scalability performance of the QCN for multicast traffic transmission and multiple unicast traffic transmission. This paper also draws a parallel between QCN for multicast traffic transmission and that for multiple unicast traffic transmission. Despite the benefit of integrating the multicast traffic, results show that performance could degrade when the network scales up. The evaluation results also show that it is probable that the feedback implosion problem caused by the bottlenecks could be solved if we choose to set the queue parameter Qeq threshold value at a high value, 3/4 of the queue capacity for instance.

Comparative study of congestion notification techniques for hop‐by‐hop‐based flow control in data centre Ethernet

“…However, IEEE 802.1Qau lacks certain qualities because, similar to the IEEE 802.3x, IEEE 802.1Qau was unable to support the priority implementation that was much needed in modern day data centres. IEEE 802.1Qau multicast communication has also been studied in [61,62]. It was shown that in a multiple-bottleneck situation IEEE 802.1Qau occasionally improves fairness issues but it cannot resolve the unfair condition to long-hop flow [62].…”

Enhanced ethernet congestion management scheme for multicast traffic

“…One of our previous works compared QCN performance for multicast traffic with that for multiple unicast traffic . While our previous work proposed to solve the feedback implosion problem by setting a high Qeq threshold value (for instance 75% of the queue capacity) , the proposed enhancement for QCN, in this paper, could solve the feedback implosion problem at low Qeq threshold values (25% of the queue capacity). Thus, our proposition for enhancement could fit the recommendation of the QCN standard (i.e.…”