A Brief History of Per-Flow QoS in the Internet

In this paper, we review the development of fine-grained quality of service (QoS) models for the Internet protocol stack. We discuss the major developments and milestones arising from substantial research work in both signalling and packet scheduling. These approaches were often coupled with the aim of providing effective multicast group communication in the network layer. However, despite significant intellectual contributions and technological advancements, production networks evolved in a different direction. The paper reflects on the driving forces for this development. The aim is to summarize these developments, provide longer-term insight that might help in assessing current research, as well as highlight the work that originated in Ralf Steinmetz’s group at TU Darmstadt.