We analyze the betweenness centrality (BC) of nodes in large complex networks. In general, the BC is increasing with connectivity as a power law with an exponent $\eta$. We find that for trees or networks with a small loop density $\eta=2$ while a larger density of loops leads to $\eta<2$. For scale-free networks characterized by an exponent $\gamma$ which describes the connectivity distribution decay, the BC is also distributed according to a power law with a non universal exponent $\delta$. We show that this exponent $\delta$ must satisfy the exact bound $\delta\geq (\gamma+1)/2$. If the scale free network is a tree, then we have the equality $\delta=(\gamma+1)/2$.

Betweenness Centrality in Large Complex Networks

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work.

/pdf/exploiting-the-power-of-multiplicity-a-holistic-survey-of-4te6h529h5.pdf

Exploiting the Power of Multiplicity: A Holistic Survey of Network-Layer Multipath

Low latency and energy efficient routing tree for wireless sensor networks with multiple mobile sinks

Recent advances in pervasive computing have caused a rapid growth of the Smart Home market, where a number of otherwise mundane pieces of technology are capable of connecting to the Internet and interacting with other similar devices. However, with the lack of a commonly adopted set of guidelines, several IT companies are producing smart devices with their own proprietary standards, leading to highly heterogeneous Smart Home systems in which the interoperability of the present elements is not always implemented in the most straightforward manner. As such, understanding the cyber risk of these cyber-physical systems beyond the individual devices has become an almost intractable problem. This paper tackles this issue by introducing a Smart Home reference architecture which facilitates security analysis. Being composed by three viewpoints, it gives a high-level description of the various functions and components needed in a domestic IoT device and network. Furthermore, this document demonstrates how the architecture can be used to determine the various attack surfaces of a home automation system from which its key vulnerabilities can be determined.

/pdf/cyber-security-of-smart-homes-development-of-a-reference-2cgiil6gxz.pdf

Cyber security of smart homes: development of a reference architecture for attack surface analysis

QoE-centric service delivery

The Internet of Things (IoT) revolution is expected to drive change in our society in an unprecedented way. It will help us collect exponentially more data in a continuous manner and get deeper insights derived from such data. There are several surveys done in the area of IoT in terms of enabling technologies, application domains, applications, protocols, and open issues. Among the open issues discussed are important concerns such as security and privacy. The low capabilities of IoT devices in terms of their energy and computing capabilities, the unreliable nature of the wireless channel, and physical vulnerability are among the contributing factors to some unique security vulnerabilities. This chapter summarizes recent research results in the area of IoT security. It emphasizes the challenges of privacy and security in IoT. The discussion considers open challenges in security and data privacy such as (1) scale and constrained network elements, (2) privacy in data collection as well as data sharing and management, and (3) identity management and authentication. The chapter presents existing literature, a critical assessment of the work that has been done, develops a perspective on the area, and evaluates trends. It also presents taxonomy of IoT security risks, attacks, and mechanisms.

Security and privacy in the Internet of Things

A Centrality Entropy Maximization Problem in Shortest Path Routing Networks

Various Centrality measures such as Degree, Closeness, and Betweenness were introduced in order to analyze networks and understand both the global dynamics of the networks and the roles played by individual nodes. It will be worthwhile to rank the centrality measures of each node and an index of the distribution of centrality measures in the entire network. In this paper, we define the notion of entropy of centrality measures, which extends the concept of centrality to the whole network. We show that this measure has wide range of applications, in network design, from designing maximally efficient networks to identifying dominance of one node or link in the context of entire network. In particular, we present an application to tactical wireless networks.

Application of entropy of centrality measures to routing in tactical wireless networks

Network topology discovery is the basis for any network management application. The problem of estimating internal structure and link-level performance from end-to-end measurements is known as network tomography. This paper proposes a novel approach to discover network characteristics, in particular, tree topology from the hop count metric (distance) between OD (Origin — Destination) pairs. The proposed method is based on Prufer encoding and decoding techniques of trees using this metric. The method also has the potential to minimize and avoid reliance on ICMP.

https://www.cse.iitm.ac.in/%7Ekamala/NCC2010_Topology_Inference_V1_1.pdf

Network (tree) topology inference based on Prüfer sequence

In the context of an IP network, we investigate an interesting case of the inverse shortest path problem using the concept of network centrality. For a given network, the centrality distribution associated with the links of a network can be determined based on the number of shortest paths passing through each link. An entropy measure for this distribution is defined, and we then forumulate the inverse shortest problem in terms of maximizing this entropy. We then obtain a centrality distribution that is as broadly distributed as possible subject to the topology constraints. An appropriate change in the weight of a link alters the number of shortest paths that pass through it, thereby modifying the centrality distribution. The idea is to obtain a centrality distribution that maximizes the entropy. This problem is shown to be NP-hard, and a heuristic approach is proposed. An application to handling link failure scenarios in Open Shortest Path First routing is discussed.

Vanniarajan Chellappan

Papers

Security and privacy in the Internet of Things

A Centrality Entropy Maximization Problem in Shortest Path Routing Networks

Application of entropy of centrality measures to routing in tactical wireless networks

Network (tree) topology inference based on Prüfer sequence

An entropy maximization problem in shortest path routing networks