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The main issue related to Software-Defined Network emulators is how to replicate real behavior in experiments. Mininet and others SDN emulators have an architecture that limits both the scope of experiments and the fidelity of networking tests. Consequently, the serialization, contention, and load of background processes may produce delays that compromise the operation of events such as transmitting a packet or completing a computation, possibly invalidating the performance evaluation of a network emulation. To address these problems, this paper presents vSDNEmul, a network emulator based on Docker container virtualization. Different from Mininet, vSDNEmul isolates each node in a container and interconnects the nodes through virtual or tunnel links. By using containers, vSDNEmul allows autonomous and flexible creation of independent network elements, resulting in more realistic emulations. This paper reports performance evaluations comparing vSDNEmul and Mininet. The results obtained with the vSDNEmul emulator are more realistic and present higher accuracy.

We present results from deep and very spatially extended CTIO/DECam $g$ and $r$ photometry (reaching out to $\sim$ 2 mag below the oldest MSTO and covering $\sim$ 20 deg$^2$) around the Sextans dSph. We use this data-set to study the structural properties of Sextans overall stellar population and its different stellar evolutionary phases, as well as to search for signs of tidal disturbance from the MW, which would indicate departure from dynamical equilibrium. We perform the most accurate structural analysis to-date of Sextans' stellar components by applying Bayesian MCMC methods to the individual stars' positions. Surface density maps are built by decontaminating the sample through a matched filter analysis of the CMD, and then analysed for departures from axisymmetry. Sextans is found to be considerably less spatially extended than early studies suggested. No significant distortions or tidal disturbances are found down to a surface brightness of $\sim$ 31.8 mag/arcsec$^{-2}$ in V-band. We identify an overdensity in the central regions that may correspond to previously reported kinematic substructure(s). In agreement with previous findings, old $\&$ metal-poor stars such as BHB stars cover a much larger area than stars in other evolutionary phases, and bright BSs are less spatially extended than faint ones. However, the different spatial distribution of bright and faint BSs appears consistent with the general age/metallicity gradients found in Sextans' stellar component. This is compatible with BSs having formed by evolution of binaries and not necessarily due to the presence of a central disrupted globular cluster, as suggested in the literature. We provide structural parameters for the various populations analyzed and make publicly available the photometric catalogue of point-sources as well as a catalogue of literature spectroscopic measurements with updated membership probabilities., Comment: 21 pages, 14 figures, 9 tables, accepted for publication in Astronomy & Astrophysics (A&A), the associated photometric and spectroscopic catalogues will be available at CDS, abstract abridged for arXiv