Intra-session Fairness Research Articles

An adaptive and predictive approach for autonomic multirate multicast networks

Autonomic communications aim at easing the burden of managing complex and dynamic networks, and designing adaptive, self-turning and self-stabilizing networks to provide much needed flexibility and functional scalability. With the ever-increasing number of multicast applications made recently, considerable efforts have been focused on the design of adaptive flow control schemes for autonomic multicast services. The main difficulties in designing an adaptive flow controller for autonomic multicast service are caused by heterogeneous multicast receivers, especially those with large propagation delays, since the feedback arriving at the source is somewhat outdated and can be harmful to the control operations. To tackle the preceding problem, this article describes a novel, adaptive, and autonomic multicast scheme, the so-called Proportional, Integrative, Derivative plus Neural Network (PIDNN) predictive technique, which consists of two components: the Proportional Integrative plus Derivative (PID) controller and the Back Propagation BP Neural Network (BPNN). In this integrated scheme, the PID controllers are located at the next upstream main branch nodes of the multicast receivers, and have explicit rate algorithms to regulate the receiving rates of the receivers; while the BPNN is located at the multicast source, and predicts the available bandwidth of those longer delay receivers to compute the expected rates of the longer delay receivers. The ultimate sending rate of the multicast source is the maximum of the aforesaid receiving rates that can be accommodated by its participating branches. This network-assisted property is different from the existing control schemes, in that the PIDNN controller can release the irresponsiveness of a multicast flow caused by those long propagation delays from the receivers. By using BPNN, this active scheme makes the control more responsive to the receivers with longer propagation delay. Thus the rate adaptation can be performed in a timely manner, for the sender to respond to network congestion quickly. We analyze the theoretical aspects of the proposed algorithm, show how the control mechanism can be used to design a controller to support multirate multicast transmission based on feedback of explicit rates, and verify this matching using simulations. Simulation results demonstrate that the proposed PIDNN controller avoids overflow of multicast traffic, and performs better than the existing scheme PNN [Tan et al. 2005] and the multicast schemes based on control theory. Moreover, it also performs well in the sense that it achieves high link utilization, quick response, good scalability, high unitary throughput, intra-session fairness and inter-session fairness.

A Distributed Efficient Flow Control Scheme for Multirate Multicast Networks

This paper proposes a novel and efficient distributed flow control scheme for multirate multicast (MR-M), based on the well-known Proportional Integral and Derivative (PID) controllers. The PID controller at each router computes its expected incoming rate and feed backs this rate to its upstream router, such that the local buffer occupancy can be stabilized at an appropriate value. We give the theoretical analysis of the proposed PID controller in terms of system stability. The proposed MR-M controller achieves the fairness in two aspects: 1) The intrasession fairness, i.e., the receivers from the same source within the same multicast session can receive data at different rates, if they subscribe networks with different capacities; 2) The intersession fairness, i.e., the link bandwidth is fairly shared among multiple multicast sessions from different sources. Extensive simulations have been conducted and the results have demonstrated a superior performance of the proposed scheme in terms of system stability, high link utilization, and high throughput.

Intra-Session Fairness in Multicast Communications

Multicast communication achieves scalability by sending data to multiple receivers at the same time. Receivers in a multicast session usually share the fate with each other, even though their processing speed and the capacity of the path they use can be quite different. A conventional multicast session usually consists of a single multicast group and the problem is how to set the group rate so that it is fair to both fast and slow receivers, to some extent. In a replicated multicast service, receivers are divided into groups based on their capacities and a multicast session can consist of multiple multicast groups. The question is how to divide receivers into groups exactly and set appropriate group rates so that it is fair to all the receivers. Most of current work focuses on optimizing the social welfare represented as a sum of some performance measures of receivers [Kar et al., 2002; Stoenescu et al., 2003]. In this paper, we define a new concept called intra-session fairness and give an optimal solution that can achieve fairness among receivers in the same session. The goal is to maximize the minimum fairness value of the receivers. The novelty of the framework is that it is independent of the specific definition of the fairness function on individual receivers. We illustrate a layering method to implement the max-min intra-session fair allocation and demonstrate the significant difference in fairness achieved by the maximal social welfare algorithm and the max-min intra-session fairness algorithm.

Congestion control scheme for reliable multicast improving intrasession fairness with network support

AbstractIn reliable multicast, the same information is transmitted to specified receiving nodes while maintaining reliability, with the information rate aligned to the receiving node with the lowest throughput by end‐to‐end control. However, the consideration of the receiving node with the lowest throughput produces the problem that other receiving nodes belonging to the same multicast group are limited to a considerably lower throughput than their own reception limits. This is a problem inherent to multicast communications, where the receiving nodes generally differ in congestion status. This fairness problem for receiving nodes is called intrasession fairness. In reliable multicast, it is impossible to realize intrasession fairness by using only end‐to‐end control. The purpose of this paper is to realize intrasession fairness by a scheme in which servers independently apply congestion control to the downlink by placing servers in the network and providing network support. The proposed scheme is evaluated by simulation. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(2): 61–70, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10125