Router mechanisms designed to achieve fair bandwidth allocations, like Fair Queueing, have many desirable properties for congestion control in the Internet. However, such mechanisms usually need to maintain state, manage buffers, and/or perform packet scheduling on a per flow basis, and this complexity may prevent them from being cost-effectively implemented and widely deployed. In this paper, we propose an architecture that significantly reduces this implementation complexity yet still achieves approximately fair bandwidth allocations. We apply this approach to an island of routers -- that is, a contiguous region of the network -- and we distinguish between edge routers and core routers. Edge routers maintain per flow state; they estimate the incoming rate of each flow and insert a label into each packet header based on this estimate. Core routers maintain no per flow state; they use FIFO packet scheduling augmented by a probabilistic dropping algorithm that uses the packet labels an...

Router mechanisms designed to achieve fair bandwidth allocations, like Fair Queueing, have many desirable properties for congestion control in the Internet. However, such mechanisms usually need to maintain state, manage buffers, and/or perform packet scheduling on a per flow basis, and this complexity may prevent them from being cost-effectively implemented and widely deployed. In this paper, we propose an architecture that significantly reduces this implementation complexity yet still achieves approximately fair bandwidth allocations. We apply this approach to an island of routers -- that is, a contiguous region of the network -- and we distinguish between edge routers and core routers. Edge routers maintain per flow state; they estimate the incoming rate of each flow and insert a label into each packet header based on this estimate. Core routers maintain no per flow state; they use FIFO packet scheduling augmented by a probabilistic dropping algorithm that uses the packet labels and an estimate of the aggregate traffic at the router. We call the scheme Core-Stateless Fair Queueing. We present simulations and analysis on the performance of this approach.

In this document we study the application of weighted proportional fairness to data flows in the Internet. We let the users set the weights of their connections in order to maximise the utility they get from the network. When combined with a pricing scheme where connections are billed by weight and time, such a system is known to maximise the total utility of the network. Our study case is a national Web cache server connected to long distance links. We propose two ways of weighting TCP connections by manipulating some parameters of the protocol and present results from simulations and prototypes. We finally discuss how proportional fairness could be used to implement an Internet with differentiated services. 1 Introduction 1.1 Fairness Fairness is among the most important properties of data flows in the Internet. Fairness implies that whenever there is congestion at a bottleneck, each flow going through that bottleneck gets a fair share of the available bandwidth. TCP flo...

Today’s Internet provides one simple service: best effort datagram delivery. This minimalist service allows the Internet to be stateless, that is, routers do not need to maintain any fine grained information about traffic. As a result of this stateless architecture, the Internet is both highly scalable and robust. However, as the Internet evolves into a global commercial infrastructure that is expected to support a plethora of new applications such as IP telephony, interactive TV, and e-commerce, the existing best effort service will no longer be sufficient. In consequence, there is an urgent need to provide more powerful services such as guaranteed services, differentiated services, and flow protection. Over the past decade, there has been intense research toward achieving this goal. Two classes of solutions have been proposed: those maintaining the stateless property of the original Internet (e.g., Differentiated Services), and those requiring a new stateful architecture (e.g., Integrated Services). While stateful solutions can provide more powerful and flexible services such as per flow bandwidth and delay guarantees, they are less scalable than stateless solutions. In particular, stateful solutions require each router to maintain and manage per flow state on the control path, and to perform per flow classification, scheduling, and buffer management on the data path. Since today’s routers can

In this paper, we study the Assured Service model proposed by Clark and Wroclawski [3, 4]. While existing schemes use service profiles that are defined in terms of absolute bandwidth, it is difficult, if not impossible, to design provisioning algorithms that achieve simultaneously good service quality and high resource utilization for such services with large spatial granularities. We propose an Assured Service model, called LIRA (Location Independent Resource Accounting), in which service profiles are defined in units of resource tokens, rather than absolute bandwidth. The number of resource tokens charged for each in-profile packet is a dynamic function of the path it traverses and the congestion level. Defining service profile in terms of resource tokens allows more dynamic and flexible network control algorithms that can simultaneously achieve high utilization and ensure high probability delivery of in-profile packets. We present an integrated set of algorithms that implement the m...

The number of heterogeneous networked applications is constantly increasing. It is likely that network resources will have to be partitioned according to the different Quality of Service (QoS) demands made by the users of these applications. One way of implementing a partitioned network -- favored in technical literature - is in terms of quality-based pricing (e.g.[1],[2],[3]). Most published proposals for partitioned networks assume users' assessments of the quality they receive mirrors the objective quality delivered at the network level (measurable through characteristics such as packet loss and delay). It is also assumed that users are prepared to pay more for higher levels of objective QoS when they need it. In this paper, we demonstrate that these assumptions may not be correct. We report an experiment in which users' QoS requirements for interactive audio were investigated. During the experiment the QoS received was linked to an expendable resource. We also established participa...

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With the grown popularity of the Internet and the increasing use of business and multimedia applications the users' demand for higher and more predictable quality of service has risen. A first improvement to offer better than best-effort services was made by the development of the integrated services architecture and the RSVP protocol. But this approach proved only suitable for smaller IP networks and not for Internet backbone networks. In order to solve this problem the concept of differentiated services has been discussed in the IETF, setting up a working group in 1997. While RSVP classifies packets according to application flow properties, differentiated services are based on the idea that the user negotiates a service profile with his Internet service provider (ISP) for specially marked packets and then transmits marked packets over the ISP network. A further significant difference to RSVP consists in the fact that for scaling reasons the service profile is only negotiated and poli...

Current charging mechanisms in the Internet are restricted mainly to volume and time of the day. Links or network clouds can have weights which may be dynamic, e.g. based on congestion level. The weight information must travel from the sender to the receiver. We provide a mechanism, which sends a message down the multicast tree for collecting the necessary information. This information can be used in the edges and the core of the network for charging. We also discuss how charging could be implemented by using these weights along links or network clouds from edge to edge. Keywords Charging, Differentiated Services, Fair Distribution of Costs, Internet Protocol, Multicast Border Router. 1 Introduction Multicasting offers an important Internet service to a variety of applications, such as conferencing, collaborative group work, or software update distributions. As the growth of the Internet in terms of traffic volume, users, hosts, links, and routers does not appear to be slowing down...

This paper describes and evaluates a probabilistic packet scheduling (PPS) algorithm for providing different levels of service to TCP flows. With our approach, each router defines a local currency in terms of tickets and assigns tickets to its inputs based on contractual agreements with its upstream routers. A flow is tagged with tickets to represent the relative share of bandwidth it should receive at each link. When multiple flows share the same bottleneck, the bandwidth that each flow obtains is proportional to the relative tickets assigned to that flow. Simulations show that PPS does a better job of proportionally allocating bandwidth than DiffServ and weighted CSFQ. In addition, PPS accommodates flows that cross multiple currency domains.