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For a (single-source) multicast network, the size of a base field is the most known and studied algebraic identity that is involved in characterizing its linear solvability over the base field. In this paper, we design a new class \mathcal N of multicast networks and obtain an explicit formula for the linear solvability of these networks, which involves the associated coset numbers of a multiplicative subgroup in a base field. The concise formula turns out to be the first that matches the topological structure of a multicast network and algebraic identities of a field other than size. It further facilitates us to unveil infinitely many new multicast networks linearly solvable over GF( q ) but not over GF( q' ) with q < q' , based on a subgroup order criterion. In particular: 1) for every k\geq 2 ) but not over GF( 2^{2k+1} ) and 2) for arbitrary distinct primes p and p' , there are infinitely many k and k' ) but not over GF( p'^k' ) with p^k < p'^k' . [ABSTRACT FROM PUBLISHER]

A fibre memory is a serial connection of fibre-switch blocks, each combining fibre delay lines with one optical switch. With enhanced flexibility in processing fluid optical data, fibre memories allow ramified applications in the existing literature. This study concentrates on the implementations of timeslot interchangers (TSIs) by fibre memories based on a special type of low-complexity switches, called rotators, under periodic switching control. The proposed TSI structure achieves an economic tradeoff between control and component complexities in the construction of large-scale optical TSIs. [ABSTRACT FROM AUTHOR]

The flexible and cost-effective service provided by cloud computing has led to the development of a vast array of applications in smart cities. Nevertheless, their traditional security approaches presented the concept of a static target for attacks, leading to an asymmetric situation between defenders and attackers. Adaptive cyber defense (ACD) has, therefore, recently emerged as a game-changer to reverse this asymmetry by reconfiguring the system according to the network scenario. Analyzing and quantifying the effectiveness of these ACDs are of high importance. Previous research on ACD analysis focused more on either studying the system properties using experiment-based approaches or on evaluating its effectiveness by different mathematical modeling approaches. However, little effort has been made to overcome the problems of isolated solutions. In this paper, we described the defensive process as a racing game between the attacker and the defender. On this basis, we conducted a thorough ACD effectiveness evaluation and suggested a comparison strategy using three methods, namely semi-Markov, stochastic reward net, and experimental methods. The obtained simulation results were approximate, and the error rate was less than 3.36% reflecting the reliability of the proposed methods. Based on the assessments, we finally summarized the features of these methods to specify and deduce different scenarios and their corresponding suitable evaluation method. [ABSTRACT FROM AUTHOR]

In order to guarantee data reliability, erasure codes have been used in distributed storage systems. Nevertheless, this mechanism suffers from the repair problem that excess data are needed to repair a single failure, causing both high bandwidth consuming for the network and heavy computing load on the replacement node. To reduce repair traffic, researchers pointed out the tradeoff between storage and repair traffic and proposed regenerating codes by combining network coding. However, the combination only focuses on the storage terminal and the construction of the codes is quite complicated. Therefore, this paper further combines network coding with network structure and proposes a repair tree model based on general erasure codes to simplify the repair procedure. By decomposing repair computing and distributing it among the tree nodes, our model can mitigate the computing tension. The performance of repair tree is analyzed and evaluated by preliminary emulation. The result shows it can make about three times faster computing than conventional measure and the repair throughput is doubled if there are network bottlenecks. For proper topology, it can significantly reduce the repair traffic. We present algorithms to generate trees across the network topology. At last, we present the idea of extending repair tree to repair multiple failures. [ABSTRACT FROM AUTHOR]

Scheduling algorithms are crucial for most existing switches to improve the throughput. However, the delay of the switching fabric cannot be guaranteed with such scheduling algorithms. This paper aims to design a novel load-balanced wire-speed multicast switching fabric along with the attractive merits of network coding. We adopt a two-phase self-routing switching fabric constructed by Boolean-multicast concentrators (SRBMCs), where the first SRBMC distributes the incoming cells to its outputs uniformly and the second allows the distributed cells to be self-routed and multicast to their destinations concurrently. To further improve the switching performance, linear network coding is smoothly combined with SRBMC to reduce the packet loss rate. Theoretical analysis and numerical simulation demonstrate that the proposed switching fabric cannot only achieve wire-speed multicast switching but also be recursively constructed into an indefinite large-scale one with such merits as no internal buffers, low complexity, and guarantee in switching delay. Finally, we implement the proposed fabric on Field-Programmable Gate Array and verify its performance in multicast switching. [ABSTRACT FROM AUTHOR]