This paper concerns the use of Active Queue Management (AQM) to reduce queuing delay. It offers insight into why it has proved hard for a Proportional Integral (PI) controller to remain both responsive and stable while controlling `Classic' TCP flows, such as TCP Reno and Cubic. Due to their non-linearity, the controller's adjustments have to be smaller when the target drop probability is lower. The PI Enhanced (PIE) algorithm attempts to solve this problem by scaling down the adjustments of the controller using a look-up table. Instead, we control an internal variable that is by definition linearly proportional to the load, then post-process it into the required Classic drop probability---in fact we show that the output simply needs to be squared. This allows tighter control, giving responsiveness and stability better or no worse than PIE achieves, but without all its corrective heuristics.

This demo dramatically illustrates how replacing 'Classic' TCP congestion control (Reno, Cubic, etc.) with a 'Scalable' alternative like Data Centre TCP (DCTCP) keeps queuing delay ultra-low; not just for a select few light applications like voice or gaming, but even when a variety of interactive applications all heavily load the same (emulated) Internet access. DCTCP has so far been confined to data centres because it is too aggressive---it starves Classic TCP flows. To allow DCTCP to be exploited on the public Internet, we developed DualQ Coupled Active Queue Management (AQM), which allows the two TCP types to safely co-exist. Visitors can test all these claims. As well as running Web-based apps, they can pan and zoom a panoramic video of a football stadium on a touch-screen, and experience how their personalized HD scene seems to stick to their finger, even though it is encoded on the fly on servers accessed via an emulated delay, representing 'the cloud'. A pair of VR goggles can be used at the same time, making a similar point. The demo provides a dashboard so that visitors can not only experience the interactivity of each application live, but they can also quantify it via a wide range of performance stats, updated live. It also includes controls so visitors can configure different TCP variants, AQMs, network parameters and background loads and immediately test the effect.

Ideally, everyone should be free to use as much of the Internet resource pool as they can take. But, whenever too much load meets too little capacity, everyone's freedoms collide. We show that attempts to isolate users from each other have corrosive side-effects - discouraging mutually beneficial sharing of the resource pool and harming the Internet's evolvability. We describe an unusual form of traffic policing which only pushes back against those who use their freedom to limit the freedom of others. This offers a vision of how much better the Internet could be. But there are subtle aspects missing from the current Internet architecture that prevent this form of policing being deployed. This paper aims to shift the research agenda onto those issues, and away from earlier attempts to isolate users from each other.

This paper introduces a novel feedback arrangement, termed re-feedback. It ensures metrics in data headers such as time to live and congestion notification will arrive at each relay carrying a truthful prediction of the remainder of their path. We propose mechanisms at the network edge that ensure the dominant selfish strategy of both network domains and end-points will be to set these headers honestly and to respond correctly to path congestion and delay, despite conflicting interests. Although these mechanisms influence incentives, they don't involve tampering with end-user pricing. We describe a TCP rate policer as a specific example of this new capability. We show it can be generalised to police various qualities of service. We also sketch how a limited form of re-feedback could be deployed incrementally around unmodified routers without changing IP.

We present a model based on congestion pricing for resource control in wireless CDMA networks carrying traffic streams that have fixed-rate requirements, but can adapt their signal quality. Our model considers the resource usage constraint in the uplink of CDMA networks, and does not differentiate users based on their distance from the base station. We compare our model with other economic models that have appeared in the literature, identifying their similarities and differences. Our investigations include the effects of a mobile's distance and the wireless network's load on the target signal quality, the transmission power, and the user benefit.

A chargeable session on the Internet may consist of more than one underlying chargeable service. Typically there will be two, one at the network layer and one at the session layer. Since different applications can have different demands from the network, a generic charging scheme has to separate the service provided by the network from the service provided by an application/service provider. In this paper we propose a pricing model which is session-based and we look at the impact of this on real-time multimedia conferencing over the Internet. In this model, we are trying to allow for the optional integration of charging at the network layer with charging at the session layer, while keeping the underlying technologies still cleanly apart. This paper also highlights the fact that the main problem of pricing application on the Internet is not just a simple case of analyzing the most technically feasible pricing mechanism but also making the solution acceptable to users. We take the position that session-based pricing is easier for end users to accept and understand and show why this is the case in this paper.

Article Nark: receiver-based multicast non-repudiation and key management Share on Authors: Bob Briscoe BT Research, B54/74, BT Adastral Park, Martlesham Heath, Ipswich, IP5 3RE, England BT Research, B54/74, BT Adastral Park, Martlesham Heath, Ipswich, IP5 3RE, EnglandView Profile , Ian Fairman BT Research, c/o B54/74, BT Adastral Park, Martlesham Heath, Ipswich, IP5 3RE, England BT Research, c/o B54/74, BT Adastral Park, Martlesham Heath, Ipswich, IP5 3RE, EnglandView Profile Authors Info & Claims EC '99: Proceedings of the 1st ACM conference on Electronic commerceNovember 1999 Pages 22–30https://doi.org/10.1145/336992.336999Online:01 November 1999Publication History 18citation569DownloadsMetricsTotal Citations18Total Downloads569Last 12 Months2Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access