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Research on VANETs (vehicular ad hoc networks) date back to the beginning of the 2000s. The possibility of enabling communication between vehicles through a wireless network stimulated the creation of new protocols, devices, and diverse utilization scenarios. Due to the intrinsic difficulties of using a real testbed to evaluate these research contributions, several simulators were developed at the time. Recently, with the advent of autonomous vehicles and the emergence of novel technologies (e.g., 5G and edge computing), new research challenges on VANETs are coming into sight. Therefore, revisiting VANET simulators is required to identify if they are still capable of evaluating these new scenarios. This paper presents an updated review of VANET simulators, showing their current state and capabilities to assess novel scenarios in VANET research. Based on this analysis, we identify open research challenges that should be addressed in current and future VANET simulators.

Network virtualization can potentially limit the impact of attacks by isolating traffic from different networks. However, routers and links are still vulnerable to attacks on the underlying network. Specifically, should a physical link be compromised, all embedded virtual links will be affected. Previous work protects virtual networks by setting aside backup resources. Although effective, this solution tends to be expensive as backup resources usually remain idle. In this paper, we present a novel virtual network allocation approach which explores the trade-off between resilience to attacks and efficiency in resource utilization. Our approach is composed of two complementary strategies, one preventive and the other reactive. The former embeds virtual links into multiple substrate paths, while the latter attempts to reallocate any capacity affected by an underlying DoS attack. Both strategies are modeled as optimization problems. Numerical results show the level of resilience to attacks and the low cost demanded by our approach.

Abstract. Network Functions Virtualization (NFV) is an emerging initiative where virtualization is used to consolidate Network Functions (NFs) onto high volume servers (HVS), switches, and storage. In addition, NFV provides flexibility as Virtual Network Functions (VNFs) can be moved to different locations in the network. One of the major challenges of NFV is the allocation of demanded network services in the network infrastructures, commonly referred to as the Network Functions Virtualization -Resource Allocation (NFV-RA) problem. NFV-RA is divided into three stages: (i) Service Function Chain (SFC) composition, (ii) SFC embedding and (iii) SFC scheduling. Up to now, existing NFV-RA approaches have mostly tackled the SFC embedding stage taking the SFC composition as an assumption. Few approaches have faced the composition of the SFCs using heuristic approaches that do not guarantee optimal solutions. In this paper, we solve the first stage of the problem by characterizing the service requests in terms of NFs and optimally building the SFC using an Integer Linear Programming (ILP) approach.