Interdependent Multi-Layer Networks: Modeling and Survivability Analysis with Applications to Space-Based Networks

Abstract

This article develops a novel approach and algorithmic tools for the modeling and survivability analysis of networks with heterogeneous nodes, and examines their application to space-based networks. Space-based networks (SBNs) allow the sharing of spacecraft on-orbit resources, such as data storage, processing, and downlink. Each spacecraft in the network can have different subsystem composition and functionality, thus resulting in node heterogeneity. Most traditional survivability analyses of networks assume node homogeneity and as a result, are not suited for the analysis of SBNs. This work proposes that heterogeneous networks can be modeled as interdependent multi-layer networks, which enables their survivability analysis. The multi-layer aspect captures the breakdown of the network according to common functionalities across the different nodes, and it allows the emergence of homogeneous sub-networks, while the interdependency aspect constrains the network to capture the physical characteristics of each node. Definitions of primitives of failure propagation are devised. Formal characterization of interdependent multi-layer networks, as well as algorithmic tools for the analysis of failure propagation across the network are developed and illustrated with space applications. The SBN applications considered consist of several networked spacecraft that can tap into each other's Command and Data Handling subsystem, in case of failure of its own, including the Telemetry, Tracking and Command, the Control Processor, and the Data Handling sub-subsystems. Various design insights are derived and discussed, and the capability to perform trade-space analysis with the proposed approach for various network characteristics is indicated. The select results here shown quantify the incremental survivability gains (with respect to a particular class of threats) of the SBN over the traditional monolith spacecraft. Failure of the connectivity between nodes is also examined, and the results highlight the importance of the reliability of the wireless links between spacecraft (nodes) to enable any survivability improvements for space-based networks.

The structure and dynamics of multilayer networks

“…Beyond power grids, it is worth noticing the completely different problem tackled in Ref. [445]. There, Authors introduced space-based networks, i.e.…”

“…the Telemetry, Tracking and Command (TTC): when one of them fails, the corresponding spacecraft can rely on the other to backup that function, and to fulfill its mission. Source: Reprinted figure from Ref [445]…”

An Interdependent Multi-Layer Model: Resilience of International Networks

“…Whatever their nature, as technology progresses we are becoming more dependent on networks and networks are simultaneously becoming more interdependent (Burger et al 2014;Rinaldi et al 2001). The organisation and growth of a network determines its success or failure and consequently influences other interdependent networks (Castet and Saleh 2013). For instance, over the last 15 years we have witnessed the exponential growth of the World Wide Web; this virtual network has transformed numerous other networks, including transportation, commerce and supply chains.…”

Identification of K most vulnerable nodes in multi-layered network using a new model of interdependency

“…For example, a i may be alive if (i) b j and b k and b l are alive, or (ii) b m and b n are alive, or (iii) b p is alive. The graph based interdependency models proposed in the literature [3], [4], [5], [9], [6], [7] including [1], [2] cannot capture such complex interdependency between entities of multilayer networks. In order to capture such complex interdependency, we propose a new model using Boolean logic.…”