QoS differentiation and Internet neutrality

Internet neutrality is a debate controversial to a tiered, application-aware Internet. Bandwidth and end-to-end delay of connections across the Internet may vary by several orders of magnitude, therefore unequal data handling per node is commonly applied to achieve differentiated QoS. This practice contradicts Internet neutrality if it is not restricted to pure application awareness. A strict separation of network operation from service provisioning would perfectly fit to achieve Internet neutrality. But this may lack economic business models for network operators, especially in a flat-rate world. This paper provides a review on differentiated quality requirements, discusses the different viewpoints of network and content providers, and closes with a discussion on potential differentiated charging intended to achieve a fair, autonomous, and cost-related revenue distribution among stakeholders.