Rajesh K. Pankaj

QoSMIC: quality of service sensitive multicast Internet protocol

In this paper, we present, QoSMIC, a multicast protocol for the Internet that supports QoS-sensitive routing, and minimizes the importance of a priori configuration decisions (such as core selection). The protocol is resource-efficient, robust, flexible, and scalable. In addition, our protocol is provably loop-free.Our protocol starts with a resources-saving tree (Shared Tree) and individual receivers switch to a QoS-competitive tree (Source-Based Tree) when necessary. In both trees, the new destination is able to choose the most promising among several paths. An innovation is that we use dynamic routing information without relying on a link state exchange protocol to provide it. Our protocol limits the effect of pre-configuration decisions drastically, by separating the management from the data transfer functions; administrative routers are not necessarily part of the tree. This separation increases the robustness, and flexibility of the protocol. Furthermore, QoSMIC is able to adapt dynamically to the conditions of the network.The QoSMIC protocol introduces several new ideas that make it more flexible than other protocols proposed to date. In fact, many of the other protocols, (such as YAM, PIMSM, BGMP, CBT) can be seen as special cases of QoSMIC. This paper presents the motivation behind, and the design of QoSMIC, and provides both analytical and experimental results to support our claims.

THE EFFECT OF ASYMMETRY ON THE ON-LINE MULTICAST ROUTING PROBLEM

In this paper, we study the problem of multicast routing on directed graphs. We define the asymmetry of a graph to be the maximum ratio of weights on opposite directed edges between a pair of nodes for all node-pairs. We examine three types of problems according the membership behavior: (i) the static, (ii) the join-only, (iii) the join-leave problems. We study the effect of the asymmetry on the worst case performance of two algorithms: the Greedy and Shortest Paths algorithms. The worst case performance of Shortest Paths is poor, but it is affected by neither the asymmetry nor the membership behavior. In contrast, the worst case performance of Greedy is a proportional to the asymmetry in a some cases. We prove an interesting result for the join-only problem: the Greedy algorithm has near-optimal on-line performance.

Admission control for cellular networks with direct QoS monitoring

This paper proposes an admission control algorithm for cellular networks based on the direct and dynamic monitoring of quality of services (QoS) performance metrics—both system delay tail and residual throughput. The main purpose of directly monitoring these QoS performance metrics is to more precisely meet the QoS requirements. The delay tail is efficiently estimated by the proposed algorithm and the total residual throughput is determined based on the total achieved throughput and total required throughput. With the estimated delay tails and measured residual throughput, the admission or rejection of a new user is determined at each base station. By doing so, the admission control algorithm improves resource utilization by guaranteeing the QoS. Additionally, the cellular system becomes more robust against the time-varying fading channel environment. The simulation results of the long term evolution downlink system show that the proposed algorithm can achieve a significant improvement in results compared to those of reference schemes. A general Neyman–Pearson-like framework is also used in evaluating the various admission control mechanisms.

QoS Performance Based Admission Control in Cellular Networks

In this paper. we consider an admission control algorithm for cellular networks. It is based on direct/dynamic monitoring of the QoS performances -- the delay tail of the admitted users. The main purpose of the direct monitoring of QoS performances is to guarantee the required QoS provision more precisely. The system delay tail is effectively computed by the proposed delay tail estimation algorithm. With the estimated delay tails, each base station determines the admission or rejection for a new user to the system. By doing so, the admission control algorithm becomes more robust against time-varying fading channel environment. Simulation results in OFDMA cellular system shows that the proposed algorithm can provide substantial capacity gains in offering QoS. We also use a general Neyman-Pearson-like framework in evaluating various admission control mechanisms.