A case for Predictive DiffServ on mobile networks

Differentiated service is intended to achieve scalable service differentiation within the network. A protocol with its QoS semantics left up to off-line service level agreements (SLAs) between the network and application, it is inapplicable to mobile environments: (1) lacks real-time QoS feedback from the network to the application; (2) cannot guarantee SLAs under dynamically changing network conditions; (3) forces the application to actively probe the network for QoS measurements thereby needlessly consuming bandwidth; and (4) can only provide network conditions information in the near past, thereby diminishing its utility. We introduce predictive DiffServ, a novel missing design point in the space of QoS network services, as an adaptable mechanism intended to provide the application with real-time, in-band predictions of network conditions, and enable the application to autonomously reconfigure its requirements in response to these conditions. Contributions include the concept, properties, architecture and API of predictive DiffServ. Additionally, we identify newly enabled application services, and portray quantitative results.