Network softwarization has revitalized the interest of the network community towards emulation as an effective mechanism for network experimentation. Relevant platforms automate the deployment of virtual network topologies on a host, providing users the ability to manually run experimental scenarios. Whilst this may suit prototyping, modern development and deployment practices such as CI/CD depend on fully automated testing processes, built around high-level testing APIs and abstracting the challenges involved with synchronizing complex node interaction scenarios. In this paper, we present Network Emulation System (NES): a cloud-native, and highly-parallelizable Network Emulation as a Service (NEaaS) platform designed from the ground up to facilitate codeless experiment specification and to automate network testing workflows in cloud CI/CD environments. We demonstrate that NES offers a 8x speedup improvement in topology instantiation times in comparison to existing emulation platforms, and its life-cycle model can automate testing processes for complex service configurations using existing CI/CD platforms such as GitHub Actions.

The physical assets within a critical infrastructure system are pivotal to its efficient performance and protection and that of other dependent systems. This is particularly the case for communication systems where network protection strategies usually involve asset redundancy. Although such redundancy is well-modelled in the literature, there is a gap in knowledge from a network science perspective in terms of its implications for network modelling and performance assessment. This paper presents a multilayer complex network framework that takes into account the heterogeneity of the redundant infrastructure for realistic network modelling and further analysis, a step change from using a single network model. Key performance indicators (KPIs) for communication networks (i.e., latency and jitter, bandwidth and throughput, queue depth and packet drops) are redefined to evaluate key important features of a long-haul backbone network such as network capacity and average use. In addition, these KPIs are adapted to deal with the aforementioned redundancy and so inform network managers with values defined over a model closer to the real system. The paper analyses the use case of a nationwide core and metro network infrastructure of one of the main UK internet service providers. The results of the analysis of KPIs showcase the advantage of the proposed multilayer complex network framework over the traditional single network model. Critical network elements within different dimensions of a communication network are identified based on their performance for prioritising network management measures.

An optical space switch based on D-fibers has been fabricated and its use in switching networks investigated. The characteristics of a switching network depend not only on the nature of the switches used, but also on the architecture utilized. In general, architectural complexity can be used in a trade with switch specification to achieve a given network behavior. Several architectures are reviewed and their consequences on the switch specification evaluated. The principles of a D-fiber space switch are described, and the switching characteristics predicted and measured. The characteristics of the switch, within its optimum architecture, enable a fully transparent network, i.e. totally nonblocking with minimum restriction on optical bandwidth, to be realized. The limits to the size of such a network are calculated using the measured characteristics of a switch fabricated in the laboratory.>

A radically new approach to optical fiber cable design and installation is described. Packages containing a number of optical fibers were drawn into preinstalled empty bores (tubes) using the viscous drag of air. The drag force acting on the fiber package is distributed along its length, which makes it possible to introduce fibers into complicated routes, with low strain. In this paper, we will concentrate mainly on the design of the fiber package, first from the point of view of the hydrodynamic forces acting on it during installation. This leads to a theoretical model for the installation process. Second, we shall consider the package as a subminiature optical fiber cable, and examine its optical performance during manufacture and temperature cycling, which leads to a theoretical model of the temperature performance of the package. Finally, we will describe a trial field installation using this cabling technique.