Topic
Network topology
About: Network topology is a research topic. Over the lifetime, 52259 publications have been published within this topic receiving 1006627 citations.
Papers published on a yearly basis
Papers
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TL;DR: The results of the topological analysis of protein structures as molecular networks describing their small‐world character are reviewed, and the role of hubs and central network elements in governing enzyme activity, allosteric regulation, protein motor function, signal transduction and protein stability is reviewed.
217 citations
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05 Dec 2005
TL;DR: A novel layered graph is proposed to model the temporarily available spectrum bands, called spectrum opportunities (SOPs), and this layered graph model is used to develop effective and efficient routing and interface assignment algorithms to form near-optimal topologies for DSA networks.
Abstract: This paper studies a fundamental problem in dynamic spectrum access (DSA) networks: given a set of detected spectrum bands that can be temporarily used by each node in a DSA network, how to form a topology by selecting spectrum bands for each radio interface of each node, called topology formation in this paper. We propose a novel layered graph to model the temporarily available spectrum bands, called spectrum opportunities (SOPs) in this paper, and use this layered graph model to develop effective and efficient routing and interface assignment algorithms to form near-optimal topologies for DSA networks. We have evaluated the performance of our layered graph approach and compared it to a sequential interface assignment algorithm. The numerical results show that the layered graph approach significantly outperforms the sequential interface assignment
217 citations
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TL;DR: This work formalizes the map of the Internet problem as a combinatorial optimization problem and considers it for two different models characterized by different types of measurements, giving several upper and lower bounds on the competitive ratio and the approximation ratio in both models.
Abstract: Due to its fast, dynamic, and distributed growth process, it is hard to obtain an accurate map of the Internet. In many cases, such a map-representing the structure of the Internet as a graph with nodes and links-is a prerequisite when investigating properties of the Internet. A common way to obtain such maps is to make certain local measurements at a small subset of the nodes, and then to combine these in order to "discover" (an approximation of) the actual graph. Each of these measurements is potentially quite costly. It is thus a natural objective to minimize the number of measurements which still discover the whole graph. We formalize this problem as a combinatorial optimization problem and consider it for two different models characterized by different types of measurements. We give several upper and lower bounds on the competitive ratio (for the online network discovery problem) and the approximation ratio (for the offline network verification problem) in both models. Furthermore, for one of the two models, we compare four simple greedy strategies in an experimental analysis
217 citations
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TL;DR: A systematic, organized overview of the alternative architectures for and design approaches to local networks, as well as comparing the current status of standards, is presented.
Abstract: The rapidly evolving field of local network technology has produced a steady stream of local network products in recent years. The IEEE 802 standards that are now taking shape, because of their complexity, do little to narrow the range of alternative technical approaches and at the same time encourage more vendors into the field. The purpose of this paper is to present a systematic, organized overview of the alternative architectures for and design approaches to local networks.The key elements that determine the cost and performance of a local network are its topology, transmission medium, and medium access control protocol. Transmission media include twisted pair, baseband and broadband coaxial cable, and optical fiber. Topologies include bus, tree, and ring. Medium access control protocols include CSMA/CD, token bus, token ring, register insertion, and slotted ring. Each of these areas is examined in detail, comparisons are drawn between competing technologies, and the current status of standards is reported.
216 citations
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20 Nov 2000TL;DR: This paper borrows the idea of fair queueing from wireline networks and defines the "fairness index" for ad-hoc network to quantify the fairness, so that the goal of achieving fairness becomes equivalent to minimizing the fairness index.
Abstract: The Medium Access Control (MAC) protocol through which mobile stations can share a common broadcast channel is essential in an ad-hoc network. Due to the existence of hidden terminal problem, partially-connected network topology and lack of central administration, existing popular MAC protocols like IEEE 802.11 Distributed Foundation Wireless Medium Access Control (DFWMAC) [1] may lead to "capture" effects which means that some stations grab the shared channel and other stations suffer from starvation. This is also known as the "fairness problem". This paper reviews some related work in the literature and proposes a general approach to address the problem. This paper borrows the idea of fair queueing from wireline networks and defines the "fairness index" for ad-hoc network to quantify the fairness, so that the goal of achieving fairness becomes equivalent to minimizing the fairness index. Then this paper proposes a different backoff scheme for IEEE 802.11 DFWMAC, instead of the original binary exponential backoff scheme. Simulation results show that the new backoff scheme can achieve far better fairness without loss of simplicity.
216 citations