A Migration Path for the Internet: From Best-Effort to a QoS Capable Infrastructure by Means of Localized Admission Control

Abstract

Looking back at many proposals appeared on the scene in these years, a fundamental lesson to be learned is that their success or failure is strictly tied to their backward compatibility with existing infrastructures. In this paper, we consider the problem of providing explicit admission control decisions for QoS aware services. We rely the decision to admit a new flow upon the successful and timely delivery, through the Internet, of probe packets independently generated by the end points. Our solution, called GRIP (Gauge&Gate Realistic Internet Protocol), is fully distributed and scalable, as admission control decisions are taken at the edge network nodes, and no coordination between routers, which are stateless and remain oblivious to individual flows, is required. The performance of GRIP are related to the capability of routers to locally take decisions about the degree of congestion in the network, and suitably block probe packets when congestion conditions are expected. The key message of this paper is that GRIP is a novel reservation paradigm which can be seamlessly applied to the existing Diffserv (and even legacy) Internet, although a marginal increase in QoS is envisioned in these existing scenarios. Indeed, GRIP opens up a future smooth migration path toward gradually improved QoS, as routers in different domain will be upgraded with better measurement-based admission decision criteria. The enabling factor is that router decision criteria are localized and do not involve any coordination. This guarantees that they can be enhanced without losing inter-operability with installed devices.