QOS for SDN-based fat-tree networks

Abstract

Software-defined Networks (SDNs) are the new network paradigm providing, programmability, agility, and centralized management. In this paper, we show how to leverage the SDN centralized controller to improve the network utilization and the traffic performance. On top of the SDN controller, new modules are added to help finding single and multi-path routes between communicating devices. Flow rules are automatically installed into the designated switches to provide the required paths. The behavior and performance of different types of traffic, namely, UDP, TCP, VOIP, and a Big-data application traffic are investigated. The traffic forwarding is based on either the controller built in layer 2 switching “odl-l2switch” feature or single/multi-path selection based on the supplemented modules. Experimental results based on metrics such as delay, jitter and packet drops are presented for each forwarding option. The results disclosed the advantage of having the developed modules on top of the controller for all traffic types. The OpenDaylight controller for OpenFlow switches, in a fat-tree network, is used for experiments. For a fair comparison of different traffic types, a monitoring module is built on top of the controller for collecting ports statistics, analyzing and monitoring.