NDTwin Application

Use two NDTwin existing applications (for energy-saving and traffic-engineering purposes, respectively) as concrete examples to demonstrate how to run up NDTwin Apps and how they optimize the operations of a network for different purposes.

Energy-Saving App

This energy-saving application will dynamically power off a switch when the average bandwidth utilization of its links drops below a low-watermark threshold and will power it on again when its average link utilization exceeds a high-watermark threshold. For a network whose topology is like that of a datacenter network with many redundnt switches to increase the total capacity of the network and reliability, this energy-saving application can dynamically and iteratively power off many under-utilized switches to greatly reduce the energy consumption of the network without degrading the Quality of Service (QoS) of the network.

Traffic-Engineering App

This traffic-enginerring application will dynamically perform load-balancing among the output ports of any Equal-Cost Multi-Path (ECMP) group in the network. In the ECMP scheme, flows are dispatched to the output ports of an ECMP group based on the hash function used by ECMP and the five-tuple infomation (i.e., the source and destination IP addresses, the source and destination port numbers, and the protocol type) in their packet headers. When the load dispatched to the output ports of many ECMP groups is imbalanced in the network, this application can significantly improve the utilization of the network.