The need for simple, scalable, and incrementally deployable router-level mechanisms to support end-to-end congestion control has been well recognized in the literature. Specifically, mechanisms for early congestion detection and fair packet dropping, such as RED, have been proposed and extensively studied. It has been shown that RED does not scale well with the number of flows, is difficult to tune dynamically, and can degenerate into tail dropping behavior under a variety of conditions. To address these problems while still retaining the robust and simple of RED, we propose a new mechanism called load adaptive fair drop (LAFD), that has no tunable parameters, and adapts effectively to the offered load and the number of flows without maintaining any pre-flow state.

Article Free Access Share on An application-level multicast architecture for multimedia communications (poster session) Authors: Kang-Won Lee Coordinated Science Laboratory, University of Illinois at Urbana-Champaign Coordinated Science Laboratory, University of Illinois at Urbana-ChampaignView Profile , Sungwon Ha Coordinated Science Laboratory, University of Illinois at Urbana-Champaign Coordinated Science Laboratory, University of Illinois at Urbana-ChampaignView Profile , Jia-Ru Li Coordinated Science Laboratory, University of Illinois at Urbana-Champaign Coordinated Science Laboratory, University of Illinois at Urbana-ChampaignView Profile , Vaduvur Bharghavan Coordinated Science Laboratory, University of Illinois at Urbana-Champaign Coordinated Science Laboratory, University of Illinois at Urbana-ChampaignView Profile Authors Info & Claims MULTIMEDIA '00: Proceedings of the eighth ACM international conference on MultimediaOctober 2000 Pages 398–400https://doi.org/10.1145/354384.354544Published:30 October 2000Publication History 3citation357DownloadsMetricsTotal Citations3Total Downloads357Last 12 Months11Last 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 SiteeReaderPDF

This paper describes a programmable switch architecture that can be dynamically tuned to support flexible quality of service metrics for flows in the Internet. The switch architecture consists of six key components: scheduling, flow aggregation, queueing, packet-level admission control, packet dropping, and feedback. We show that it is possible to achieve a wide range of QoS behavior ranging from strict per-flow rate and delay guarantees to coarse per-class rate assurances by programming the components appropriately.

Single-rate reliable multicast protocols are known to have scalability problems in the presence of a large number of receivers because the sender cannot distinguish independent packet losses at different receivers from multiple packet losses at the same receiver. In the presence of a large number of receivers, the sender may perceive a large aggregate packet loss even if no individual receiver is highly congested. Consequently, the multicast session progresses at a much slower rate than its desired sending rate. In order to solve this problem, we argue for decoupling of the mechanisms to achieve congestion control and reliability in reliable multicast protocols, and present a very simple "loss notification"-based multicast congestion control mechanism that can be used to augment both ACK-based and NAK-based reliable multicast protocols and solve the independent packet loss problem. We illustrate the efficacy of our approach via simulations using the ns2 simulator.

The Illinois Reliable Multicast Architecture (IRMA) is a reliable multicast architecture that guarantees reliable, sequenced, and loosely synchronized delivery of multicast streams. IRMA provides ACK-based reliability, hybrid local server-initiated and sender-initiated loss recovery, and support for end-to-end flow control and congestion control. Unlike most contemporary work, IRMA supports TCP as the reliable multicast transport protocol at the end host without modifications. IRMA has been instantiated in a laboratory testbed, and its performance has been measured in various scenarios. Preliminary performance results show that IRMA is efficient and adaptive to the dynamics of the network.

We present a new transport protocol called HPF for effectively supporting heterogeneous packet flows in the Internet environment. The following are the key features of HPF: HPF supports packet flows where different packets in the same transport connection have different quality-of service requirements in term of reliability, priority, and deadlines. HPP supports application-level framing, and provides APIs for applications to specify the priority, reliability and timing requirements of each frame. HPF enables the use of application-specified priorities as hints for network routers to preferentially drop low-priority packets during congestion. This ensures that 'important data' gets through preferentially during congestion. HPF decouples the congestion control and reliability mechanisms in order to support congestion control for unreliable and heterogeneous packet flows. Preliminary performance measurements in our experimental testbed show that HPF can provide effective support for heterogeneous packet flows in the presence of dynamic network resources.

This paper studies the performance of a large class of scheduling algorithms, and investigates the interaction between the application and the network to improve performance under congestion. The following key ideas are presented in this paper: (a) we show the performance and scalability trade-offs between providing separation and multiplexing among flows; (b) we show that a bounded buffer FIFO scheduler performs approximately as well as a weighted round robin scheduler with per-flow queues in most practical situations, but requires significantly less overhead in terms of per-flow state; and (c) we show how link layer schedulers can use application-level hints in order to increase the perceived goodness of connections at higher layers.