Distributed Network Emulator Research Articles

Fidelity-aware large-scale distributed network emulation

The design and development of new network protocols, architectures, and technologies requires an evaluation phase where the researcher must provide empirical evidence for the performance of their contributions, potentially in comparison to existing solutions. In this context, network emulation has proven to be an attractive approach as it offers more flexibility compared to traditional testing platforms, and more realism compared to simulation. Network emulators provide contained, customisable, and scalable testing environments both for researchers to evaluate their contributions and for the community to reproduce their results. However, two limitations to network emulation have been identified and well documented in the literature: its scalability limits and its accuracy issues. This paper11This journal paper is an extension of a shorter paper (Elbouanani et al., 2023 [1]) previously presented in the TASIR (Testbeds for Advanced Systems Implementation and Research) workshop of Comsnets 2023 conference, and published in its proceedings. documents our attempts to address these concerns. Our findings are distilled into Hifinet: a lightweight scalable and fidelity-aware distributed network emulator. We particularly show how Hifinet outperforms its state-of-the-art counterparts in terms of scalability and efficiency by working around the flaws of their design principles and the technological limitations of the tools they rely on. Hifinet is also fidelity-enhanced, in that it implements a well-theorised fidelity monitoring framework, which passively monitors emulated packet delays to evaluate realism of network emulation and accuracy of results. Another asset of Hifinet is its ability to infer underlying causes in case of erroneous emulation and guide the user through fixing them. This is achieved by using delay tomography algorithms and heuristics.

Troubleshooting distributed network emulation

Troubleshooting distributed network emulation

Improving the Scalability of Distributed Network Emulations: An Algorithmic Perspective

By deploying virtualized network elements (hosts, switches, routers, links, etc.) on clusters of commodity machines, distributed network emulations (DNE) closely mimic the behaviors of network systems and provide real-time interactions and analysis for network service management. However, DNE encounters scalability challenges when faced with large network topologies. These challenges can be boiled down to the assignment problem: to which physical machine each virtualized network element should be assigned so that the largest possible network topology can be emulated? In this paper, we tackle this problem from an algorithmic perspective. We first propose TBR (topology balancing relaxation) as the relaxation of the assignment problem. TBR tries to maintain a balance of the hardware resource consumption, by minimizing the maximum inter-machine bandwidth. We further develop TBS (topology balancing solver), which combines mathematical techniques with multi-level algorithms to solve TBR efficiently. We integrate TBR and TBS into MaxiNet, a famous distributed network emulator. Experimental results show that with the same available physical resources, TBR and TBS can improve emulation scalability by up to 4.7× compared to baselines.

An Approach to Remote Update Embedded Systems in the Internet of Things

There is a growing initiative on the part of regulatory bodies to employ control over firmware emissions destined for Internet of Things (IoT) devices. In this scenario, this paper presents a new approach, called SOTARU, which proposes the use of a consortium Blockchain among embedded system manufacturers as a way to allow access to the update history of devices from multiple manufacturers through a single infrastructure. The security and robustness of the proposal were evaluated with the help of the Common Open Research Emulator (CORE) distributed network emulator. As a result, it was found that SOTARU stands out in terms of security when compared to other approaches proposed in the literature, as well as being functional even in high latency scenarios.

Passive delay measurement for fidelity monitoring of distributed network emulation

Emulation has become a popular approach for the validation and evaluation of network research. It provides researchers with a contained, customizable, and scalable testing environment, which can be easily packaged and published for potential readers to reproduce their results. However, as the network components are only virtual, emulation lacks the inherent realism of physical testbeds. In light of this, monitoring specific metrics of the emulated network has been proposed as a solution to mitigate to some degree inaccuracies caused by emulation. While this is not difficult to implement in a single-machine setting (e.g. with Mininet), monitoring is limited by the lack of time synchronization in scenarios where the emulation is distributed over multiple physical machines (e.g., Distrinet). In this paper we tackle the case of packet delay monitoring, to which we propose a methodology for passively measuring one-way delays with underlying assumptions about time synchronization, and round-trip delays otherwise. For an efficient implementation of our methodology, we propose an eBPF-based packet measurement tool that performs better than current packet sniffers under emulation-specific assumptions. We implement and evaluate our system in an open testbed and show that it can reach results within few microseconds of perfect accuracy and precision.