We study a priority service where users are free to choose the priority of their traffic, but are charged accordingly by the network. We assume that each user chooses priorities to maximize its own net benefit, and model the resulting interaction among users as a noncooperative game. We show that there exists an unique equilibrium for this game and that in equilibrium the bandwidth allocation is weighted max-min fair.

This paper studies the quality of service (QoS) provision problem in noncooperative networks where applications or users are selfish and routers implement generalized processor sharing (GPS)-based packet scheduling. First, we formulate a model of QoS provision in noncooperative networks where users are given the freedom to choose both the service classes and traffic volume allocated, and heterogenous QoS preferences are captured by individual utility functions. We present a comprehensive analysis of the noncooperative multi-class QoS provision game, giving a complete characterization of Nash equilibria and their existence criteria, and show under what conditions they are Pareto and system optimal. We show that, in general, Nash equilibria need not exist, and when they do exist, they need not be Pareto nor system optimal. However, we show that for certain "resource-plentiful" systems, the world indeed can be nice with Nash equilibria, Pareto optima, and system optima collapsing into a s...

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This paper presents an adaptive end-to-end protocol for quality of service-sensitive transport of real-time MPEG video using packet-level forward error correction in dynamic networks. The objective is to facilitate a user-specified QoS end-to-end - i.e., without special network support - for real-time MPEG video whose timing constraints rule out the use of retransmission-based congestion control and QoS provisioning schemes. The degree of redundancy - overcode in forward error correction - injected into the network is adjusted as a function of network state, decreasing when the network is well-behaved to minimize unnecessary network resource consumption, and increasing when it is not to compensate for adverse network effects so as to maintain an invariant level of end-to-end QoS. We describe an adaptive packet-level FEC protocol called AFEC and analyze its properties with respect to optimality and stability. The optimal control problem is nontrivial due to the fact that increased redundancy, b...

This paper presents an architecture for multi-class quality of service (QoS) provision in wide area networks. Users or applications are assumed to be selfish and end-to-end QoS is determined by the service levels received by an application traffic flow at each router or switch along a path. In previous work, we have given a comprehensive analysis of the noncooperative multi-class QoS provision game for single-switch systems showing when Nash equilibria exist and under what conditions they are Pareto and/or system optimal. In this paper, we propose a specific network architecture for facilitating noncooperative QoS provision in many-switch systems such as the Internet with emphasis on realizability. We shield the user from having to choose the service classes on the switches along a route---a hard combinatorial optimization problem even assuming perfect knowledge about network state---while preserving the basic premise of selfishness. This is achieved by employing a set of QoS agents in...

Architecting networks capable of providing scalable, efficient, and fair services to users with diverse QoS requirements is a challenging problem. The differentiated services framework has advanced a set of building blocks comprised of per-hop and access point behaviors with the aim of facilitating scalable services through aggregate-flow control inside the network and per-flow traffic control at the edge. In spite of recent efforts, little is known about how to select "good" per-hop and edge controls, in part, due to a lack of cohesive criteria with respect to which the choices can be effectively reasoned, evaluated, and justified. In this paper, we provide a theoretical framework for reasoning about differentiated services networks, constrained to be implementable in IP networks. The control framework incorporates assumptions, albeit weak, about selfish user behavior and service provider behavior. This is necessitated by the essential role they play in influencing end-to-end QoS, wi...

The relative differentiation architecture does not require per-flow state at the network core or edges, nor admission control, but it can only provide higher classes with better service than lower classes. A central premise in this context is that users with absolute QoS requirements should dynamically search for an appropriate class. We investigate this Dynamic Class Selection (DCS) framework, and illustrate that, under certain conditions, DCS-capable users can meet absolute QoS requirements, even though the network only offers relative differentiation. For a single link model, we can examine whether it is feasible to satisfy all users, and when this is the case, compute the minimum acceptable class selection for each user. Users converge in a distributed manner to this minimum acceptable class, if the DCS equilibrium is unique. However, suboptimal DCS equilibria may also exist. Simulations of a delay-based DCS algorithm show the relation between class differentiation and DCS, and demonstrate how to control the trade-off between the performance and cost of a flow.

Packet-switched network technology is expected to form the integration layer for future multi-service networks. The trend to integrate voice and data traffic can already be observed in the Internet and is expected to carry on until the full integration of all media types is achieved. At the same time it becomes obvious that the business model employed for current Internet usage is probably not sustainable for the creation of an infrastructure suitable to support a diverse and ever-increasing range of application services. Currently, the Internet provides only a single class of best-effort service and prices are mainly built on flat-fee, access-based schemes. However, the large and increasing differentiation of demand for quality of transmission services creates the necessity to differentiate service provision and, consequently, charging for network communications. In this article, we survey relevant service models and motivate the need for appropriate charging mechanisms. We give an overview on requirements for a charging system, its technical components, and issues for future business models that might by employed by service providers.

End-to-end QoS control over best-effort and differentiated service networks which exhibit variability in their exported service properties looms as an important challenge. In previous work, we have shown how packet-level adaptive FEC can be used in dynamic networks to facilitate invariant user-specified QoS in an end-to-end manner. This paper addresses two important problems---self-similar burstiness and performance degradation of reactive controls subject to long feedback loops---complementing the stability/optimality considerations studied earlier. First, for adaptive redundancy control to be effective, its susceptibility to correlated packet drops and queueing delays stemming from selfsimilar burstiness must be fortified. Second, to preserve FEC's viability over ARQ when transporting real-time traffic in WANs, proactivity must be injected to offset the performance degradation of reactive feedback controls when subject to long RTTs. In this paper, we use the recently advanced multi...

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