A Survey of PCN-Based Admission Control and Flow Termination

Pre-congestion notification (PCN) provides feedback\ud about load conditions in a network to its boundary nodes. The PCN working group of the IETF discusses the use of PCN to implement admission control (AC) and flow termination (FT) for prioritized realtime traffic in a DiffServ domain. Admission control (AC) is a well-known flow control function that blocks admission requests of new flows when they need to be carried over a link whose admitted PCN rate already exceeds an admissible rate. Flow termination (FT) is a new flow control function that terminates some already admitted flows when they are carried over a link whose admitted PCN rate exceeds a supportable rate. The latter condition can occur in spite of AC, e.g., when traffic is rerouted due to network failures.\ud This survey gives an introduction to PCN and is a primer for\ud this new technology. It presents and discusses the multitude of architectural design options in an early stage of the standardization process in a comprehensive and streamlined way before only a subset of them is standardized by the IETF. It brings PCN from the IETF to the research community and serves as historical record

Analytical Study of Pre-Congestion Notification (PCN) Techniques

Maintaining the quality of service (QOS) and controlling the network congestion are quite complicated tasks. They cause degrading the performance of the network, and disturbing the continuous communication process. To overcome these issues, one step towards this dilemma has been taken in form of Pre-congestion notification (PCN) technique. PCN uses a packet marking technique within a PCN domain over IP networks. It is notified by egress node that works as guard at entry point of network. Egress node gives feedback to communicating servers whether rate on the link is exceeded than configured admissible threshold or within the limit. Based on this feedback, admission decisions are taken to determine whether to allow/block new coming flows or terminate already accepted. The actual question is about selection of right algorithm for PCN domain. In this paper, we investigate the analytical behavior of some known PCN algorithms. We make slide modifications in originality of PCN algorithms without disquieting working process in order to employ those within similar types of scenarios. Our goal is to simulate them either in highly congested or less congested realistic scenarios. On the basis of simulation done in ns2, we are able to recommend each PCN algorithm for specific conditions. Finally, we develop a benchmark that helps researchers and scientific communities to pick the right algorithm. Furthermore, the benchmark is designed to achieve specific objectives according to the users’ requirements without congesting the network

Protecting video service quality in multimedia access networks through PCN

The growing popularity of video-based services and their corresponding unpredictable bursty behavior makes the design of an admission control system an important research challenge. The pre-congestion notification (PCN) mechanism is a measurement-based approach, recently standardized by the IETF, optimized toward the admission of inelastic flows, where the number of flows is sufficiently large that individual bursts of flows can be compensated by silence periods of others. In this article, we discuss the implications of applying PCN to protect video services, which have less predictable behavior. Several algorithms for protecting video services in multimedia access networks are described. Through performance evaluation, we show the impact of these algorithms on the network utilization and video quality, and present guidelines on how to configure a PCN system

Pre-Congestion Notification (PCN) Architecture

This document describes a general architecture for flow admission and termination based on pre-congestion information in order to protect the quality of service of established, inelastic flows within a single Diffserv domain.\u

Joint in-network video rate adaptation and measurement-based admission control: algorithm design and evaluation

The important new revenue opportunities that multimedia services offer to network and service providers come with important management challenges. For providers, it is important to control the video quality that is offered and perceived by the user, typically known as the quality of experience (QoE). Both admission control and scalable video coding techniques can control the QoE by blocking connections or adapting the video rate but influence each other's performance. In this article, we propose an in-network video rate adaptation mechanism that enables a provider to define a policy on how the video rate adaptation should be performed to maximize the provider's objective (e.g., a maximization of revenue or QoE). We discuss the need for a close interaction of the video rate adaptation algorithm with a measurement based admission control system, allowing to effectively orchestrate both algorithms and timely switch from video rate adaptation to the blocking of connections. We propose two different rate adaptation decision algorithms that calculate which videos need to be adapted: an optimal one in terms of the provider's policy and a heuristic based on the utility of each connection. Through an extensive performance evaluation, we show the impact of both algorithms on the rate adaptation, network utilisation and the stability of the video rate adaptation. We show that both algorithms outperform other configurations with at least 10 %. Moreover, we show that the proposed heuristic is about 500 times faster than the optimal algorithm and experiences only a performance drop of approximately 2 %, given the investigated video delivery scenario