Vehicles such as cars are expected to use communication technologies for retrieving different kinds of information and exchanging information with other vehicles for safety and infotainment purposes. This results in vehicular networks, where vehicles can connect to other vehicles or communication infrastructures such as Road Side Units. The Recursive Inter- Network Architecture (RINA) has been proposed as a Future Internet architecture. This paper investigates and analyses how vehicular networks can be supported by RINA and how a RINA based vehicular network architecture can be designed to support efficient management of mobile vehicles.

With the increasing usage of cloud computing and dependence on a diverse set of distributed applications, users are reliant on consistent outcomes from a shared infrastructure. This drives the need for improved QoS guarantees for heterogeneous communication requirements over shared networks. The Recursive Inter-Network Architecture (RINA) is a fundamental programmable network architecture that provides a consistent model for supporting QoS across multiple layers. In this work we evaluate the performance outcomes provided by such polyservice RINA networks in conjunction with per-layer ΔQ-based resource allocation policies. ΔQ provides a resource allocation model able to enforce strict statistical limits on the maximum experienced losses and delays through the smart utilization of traffic policing and shaping strategies, together with an analytical pre-dimensioning of buffer thresholds. Our target scenario is a backbone network that prioritizes communications among geographically distributed datacentres using resources shared with best-effort background traffic. Results obtained with the RINASim simulation software show that a ΔQ-enabled RINA network can yield the desired absolute QoS guarantees to the assured traffic classes without negatively impacting the rest, unlike current MPLS-based VPN solutions.

With the proliferation of cloud computing and the expected requirements of future Internet of Things (IoT) and 5G network scenarios, more efficient and scalable Data Centers (DCs) will be required, offering very large pools of computational resources and storage capacity cost-effectively. Looking at todays' commercial DCs, they tend to rely on well-defined leaf-spine Data Center Network (DCN) topologies that not only offer low latency and high bisectional bandwidth, but also enhanced reliability against multiple failures. However, routing and forwarding solutions in such DCNs are typically based on IP, thus suffering from its limited routing scalability. In this work, we quantitatively evaluate the benefits that the Recursive InterNetwork Architecture (RINA) can bring into commercial DCNs. To this goal, we propose rule-based topological routing and forwarding policies tailored to the characteristics of publicly available Google's and Facebook's DCNs. These policies can be programmed in a RINA-enabled environment, enabling fast forwarding decisions in most scenarios with merely neighboring node information. Upon DCN failures, invalid forwarding rules are overwritten by exceptions. Numerical results show that the scalability of our proposal depends on the number of concurrent failures in the DCN rather than its size (e.g., number of nodes/links), dramatically reducing the total amount of routing and forwarding information to be stored at nodes. Furthermore, as routing information is only disseminated upon failures across the DCN, the associated communication cost of our proposals largely outperforms that of the traditional IP-based solutions.

Rigid fixed-grid wavelength division multiplexing (WDM) optical networks can no longer keep up with the emerging bandwidth-hungry and highly dynamic services in an efficient manner. As the available spectrum in optical fibers becomes occupied and is approaching fundamental limits, the research community has focused on seeking more advanced optical transmission and networking solutions that utilize the available bandwidth more effectively. To this end, the flexible/elastic optical networking paradigm has emerged as a way to offer efficient use of the available optical resources. In this work, we provide a comprehensive view of the different pieces composing the “flexible networking puzzle” with special attention given to capturing the occurring interactions between different research fields. Only when these interrelations are clearly defined, an optimal network-wide solution can be offered. Physical layer technological aspects, network optimization for flexible networks, and control plane aspects are examined. Furthermore, future research directions and open issues are discussed.

Elastic flexgrid optical networks (FG-ON) are considered a very promising solution for next-generation optical networks. In this article we focus on lightpath adaptation under variable traffic demands in FG-ON. Specifically, we explore the elastic spectrum allocation (SA) capability of FG-ON and, in this context, we study the effectiveness of three alternative SA schemes in terms of the network performance. To this end, we formulate a Multi-Hour Routing and Spectrum Allocation (MH-RSA) optimization problem and solve it by means of both Integer Linear Programming (ILP) and efficient heuristic algorithms. Since, as numerical results show, the effectiveness of SA schemes highly depends on the traffic demand profile, we formulate some indications on the applicability of elastic SA in FG-ON.

The existing dimensioning strategy for translucent, sub-wavelength switching architectures relies on over-provisioning, and consequently, overuse of costly, power-consuming optical-electrical-optical (O/E/O) regenerators. In addition, due to a variety of external phenomena, many physical layer impairments are time-varying, and hence, can strongly degrade network performance. In this work, we introduce a Cross-Layer Optical Network Element (CLONE) used for the dynamic management of physical layer impairments in the network. We investigate the impact of real-time impairment aware routing in a CLONE-enabled optical network with sub-wavelength switching. Simulation results show that the CLONE-enabled network architecture provides improvements in: (1) energy efficiency by optimizing the usage of regenerators, and (2) network performance in terms of the packet loss probability.

Advances in optical transmission technology are driving the evolution from legacy opaque toward transparent backbone networks. Aiming at reducing the costs and energy consumption, transparent networks allow the data to be kept optical end to end and thus removing the majority of the expensive optical-electrical-optical (OEO) devices. Nonetheless, physical impairments accumulate on the signal along optical transparent paths, therefore limiting the system reach and the overall network performance. Furthermore, failures propagate in a transparent network environment and they cannot be easily localized and isolated. So then, transparent networks need to deal with a number of challenges impacting both planning and operation phases. Such challenges require the use of cross-layer approaches, which involve dynamic interactions between the physical layer and the network layer to enable the compensation for mismatching of requirements and resources. In this paper, we aim to provide an overview of such challenges, reporting comparative analysis with a selection of existing solutions and to cast a glance at the open issues for future research.

Compact routing schemes address the fundamental tradeoff between the memory space required to store the routing table entries and the length of the routing paths that these schemes produce. This paper introduces the first known nameindependent, leaf-initiated dynamic compact routing scheme that allows the distribution of traffic from any source to any set of leaf nodes along a multicast routing path that defines a distribution tree. By means of the proposed scheme, a multicast distribution tree dynamically evolves according to the arrival of leaf-initiated join/leave requests. To evaluate the performance we consider the following metrics: the stretch of the produced routing paths, the size and the number of routing table entries, and the communication cost. The results obtained by simulation on synthetic power law graphs (modeling the Internet topology) show that our scheme can successfully handle leaf-initiated dynamic setup of multicast distribution trees. Two reference multicast routing schemes (the Shortest Path Tree and the Steiner Tree algorithm) are used to compare the performance of the proposed scheme. While increasing the communication cost compared to the Shortest Path Tree, the proposed scheme achieves considerable reduction of the routing table size compared to both reference schemes. Moreover, the stretch of the resulting multicast routing paths show limited deterioration compared to the minimum value obtained with Steiner Trees.

In this paper, we deal with the physical layer impairments (PLIs) in optical burst switching (OBS). In particular we present a formulation of the routing and regenerator placement and dimensioning (RRPD) problem for a feasible translucent OBS (T-OBS) network architecture. Since addressing the joint RRPD problem results in an extremely complex undertaking, we decouple the problem, and hence, we eventually provide formal models to solve routing and RPD separately in the socalled R+RPD problem. Thus, making use of mixed integer linear programming (MILP) formulations, we first address the routing problem with the aim of minimizing congestion in bottleneck network links, and second, we tackle the issue of performing a sparse placement of electrical regenerators in the network. Since the RPD formulation requires high computational effort for large problem instances, we also propose two alternative heuristic strategies that provide good near-optimal solutions within reasonable time limits. To be precise, we evaluate the trade-off between optimality and complexity provided by these methods. Finally, we conduct a series of simulation experiments on the T-OBS network that prove that the R+RPD strategies effectively deal with burst losses caused by the impact of PLIs, and therefore, ensure that the overall T-OBS network performance remains unaffected.

This paper introduces a Generalized Multi-Protocol Label Switching (GMPLS)-enabled Optical Burst Switched (OBS) network architecture featuring end-to-end QoS-aware burst transport services. The proposed GMPLS/OBS architecture guarantees specific burst loss probability requirements, independently of the offered network load. This is achieved through the configuration of burst Label Switched Paths (LSPs) over the network which are set-up at the GMPLS control plane level only, while it is the OBS node controller the responsible for eventually committing data plane resources upon burst arrival. In such a way, statistical multiplexing feature is preserved and, at the same time, the end-user QoS demands are met by tightly dimensioning the LSPs. A Mixed Integer Linear Programming (MILP) model is devised to provide the optimal burst LSPs dimensioning according to the offered network load and QoS requirements. Moreover, GMPLS-driven capacity reconfigurations are dynamically triggered whenever unfavorable network conditions are detected. The performance of the proposed architecture is extensively assessed on several network scenarios. Future work on the topic is finally outlined.

Energy consumption and the concomitant Green House Gases (GHG) emissions of network infrastructures are becoming major issues in the Information and Communication Society (ICS). Current optical network infrastructures (routers, switches, line cards, signal regenerators, optical amplifiers, etc.) have reached huge bandwidth capacity but the development has not been compensated adequately as for their energy consumption. Renewable energy sources (e.g. solar, wind, tide, etc.) are emerging as a promising solution both to achieve drastically reduction in GHG emissions and to cope with the growing power requirements of network infrastructures. The main contribution of this paper is the formulation and the comparison of several energy-aware static routing and wavelength assignment (RWA) strategies for wavelength division multiplexed (WDM) networks where optical devices can be powered either by renewable or legacy energy sources. The objectives of such formulations are the minimization of either the GHG emissions or the overall network power consumption. The solutions of all these formulations, based on integer linear programming (ILP), have been observed to obtain a complete perspective and estimate a lower bound for the energy consumption and the GHG emissions attainable through any feasible dynamic energy-aware RWA strategy and hence can be considered as a reference for evaluating optimal energy consumption and GHG emissions within the RWA context. Optimal results of the ILP formulations show remarkable savings both on the overall power consumption and on the GHG emissions with just 25% of green energy sources.

Most research works in optical burst switching (OBS) networks do not take into account the impact of physical layer impairments (PLIs) either by considering fully transparent (i.e., using optical 3R regeneration) or opaque (i.e., electrical 3R regeneration) networks. However, both solutions are not feasible for different reasons. In this paper, we propose a novel translucent OBS network architecture which aims at bridging the gap between the transparent and opaque solutions. In order to evaluate its performance, two different joint regenerator placement and routing heuristics are provided. Simulation results show that our translucent network model achieves performance results as good as those obtained with an opaque solution but with considerably less regenerators.

This paper investigates routing algorithms that compute paths along which combined unicast and multicast traffic can be forwarded altogether, i.e., over the same path. For this purpose, the concept of AnyTraffic group is introduced that defines a set of nodes capable to process both unicast and multicast traffic received from the same (AnyTraffic) tree. The resulting scheme is referred to as AnyTraffic routing. This paper defines a heuristic algorithm to accommodate the AnyTraffic group and to find the proper set of branch nodes of the tree. The algorithm supports dynamic changes of the leaf node set during multicast session lifetime by adapting the corresponding tree upon deterioration threshold detection. Studies are performed for both static and dynamic traffic scenarios to i) determine the dependencies of the algorithm (node degree, clustering coefficient and group size); and ii) evaluate its performance under dynamic conditions. Initial results show that the AnyTraffic algorithm can successfully handle dynamic requests while achieving considerable reduction of forwarding state consumption with small increase in bandwidth utilization compared to the Steiner Tree algorithm.

The high capacity provided by packet-switched networks is supporting the proliferation of bandwidth intensive multimedia applications which require multicasting capability. As a consequence on today's networks, unicast and multicast traffic compete for shared resources where a router must maintain both unicast and multicast forwarding states. Pursuing a forwarding state reduction, in this paper we introduce the novel concept of Any Traffic data group which consists of a group of nodes receiving both unicast and multicast traffic over the same single minimum-cost network entity. A novel heuristic algorithm is specifically defined to accommodate such data group and has been compared with the standard shortest path (SP) algorithm - the optimal case for unicast routing - and a classical Sterner tree (ST) heuristic algorithm - the optimal case for multicast routing. Exhaustive experiments have been performed to validate the proposed algorithm.

Optical burst switching architectures without buffering capabilities are sensitive to burst congestion. The existence of a few highly congested links may seriously aggravate the network throughput. Proper network routing may help in congestion reduction. The authors focus on adaptive routing strategies to be applied in labelled OBS networks, that is, with explicit routing paths. In particular, two isolated alternative routing algorithms that aim at network performance improvement because of reactive route selection are studied. Moreover, a nonlinear optimisation method for multi-path source-based routing, which aims at proactive congestion reduction is proposed. Comparative performance results are provided and some implementation issues are discussed.

This paper focuses on the problem of quality of service (QoS) provisioning in optical burst switching (OBS) networks. OBS is a promising photonic network technology aiming at efficient transport of IP traffic by means of statistical multiplexing. The lack of optical memories, however, makes this operation quite complicated. Problems such as unfairness in access to the shared transmission resources, facility in adopting alternative and backup routing, scheduling complexity and so on arise in the conventional OBS architecture. In this paper we proposed the offset-time emulated OBS (E-OBS) architecture, which overcomes all these drawbacks by means of distributed provisioning of the offset time in core nodes. Nonetheless it is still difficult to guarantee a certain level of service quality. Burst preemption mechanism, which, alongside with offset-time differentiation, was proven to be the most effective technique for QoS provisioning in OBS networks. The general drawback of any burst preemption-based mechanism is that, in case of successful preemption, either the resources reserved for the preempted bursts on outgoing path are wasted or an additional signaling procedure should be carried out in order to release them. In order to avoid wasted resources reservation, we also proposed the preemption Window (PW) mechanism which enhances the E-OBS for efficient QoS support. In this paper we evaluate exhaustively the performance of the resulting architecture showing all its advantageous with respect to other solutions.

This papers reports the advances in optical core networks research coordinated in the framework of the e- photon/ONe and e-photon/ONe+ networks of excellence.

This paper considers an optical packet-switched node with limited buffer capabilities and subject to asynchronous, variable-length packets and connection-oriented operation. In such a scenario, we address the problem of providing QoS. While existing solutions focus on applying some form of resources reservation on top of the contention resolution algorithm, here we propose a novel method: given a set of K categories of service to be provided in the network, K different contention resolution algorithms are implemented to cope with the requirements of such service categories. In this paper, we define three different OPS service categories based on three different contention resolution algorithms, we design an ad-hoc pool of fiber delay lines for such a scheme, and evaluate its performance by simulation. The obtained results indicate the merits of our method which opens up future interesting developments for a whole network scenario studies.

The data and voice integration over dense wavelength-division-multiplexing (DAVID) project proposes a metro network architecture based on several wavelength-division-multiplexing (WDM) rings interconnected via a bufferless optical switch called Hub. The Hub provides a programmable interconnection among rings on the basis of the outcome of a scheduling algorithm. Nodes connected to rings groom traffic from Internet protocol routers and Ethernet switches and share ring resources. In this paper, we address the problem of designing efficient centralized scheduling algorithms for supporting multiclass traffic services in the DAVID metro network. Two traffic classes are considered: a best-effort class, and a high-priority class with bandwidth guarantees. We define the multiclass scheduling problem at the Hub considering two different node architectures: a simpler one that relies on a complete separation between transmission and reception resources (i.e., WDM channels) and a more complex one in which nodes fully share transmission and reception channels using an erasure stage to drop received packets, thereby allowing wavelength reuse. We propose both optimum and heuristic solutions, and evaluate their performance by simulation, showing that heuristic solutions exhibit a behavior very close to the optimum solution.