Communication networks are subject to many challenges leading to single or multiple failures of its elements. Example failure scenarios include unintentional
failures due to scheduled maintenance activities or massive failures caused by disaster-induced events. Therefore, it is crucial to enhance the networks with redundancy and resilience mechanisms able to maintain the availability of network services after a failure. As these problems are often inherently hard to solve to optimality, the role of time-efficient approximation schemes is essential. In this paper, we highlight the selected problems of communication networks resilience addressed in this issue of Networks.
In case of maritime communications, we observe a growing interest in deployment of multitask satellite-based solutions and development of new maritime-specific systems intended for improvements in safety of e-navigation. Analysis of different types of currently used maritime communication systems leads, however, to a conclusion that neither global and still very expensive satellite systems nor cheaper, but short-ranged transmission technologies can, on their own, fully meet the today's expectations and quality requirements formulated for broadband maritime systems. This lack of reliable solutions, offering high throughput and ubiquitous availability of coverage to a wide audience at a relatively low price is one of the main barriers in a widespread implementation of e-navigation initiatives.
This issue is addressed in the netBaltic project with the objective to design, deploy and validate in a real maritime environment a non-satellite wireless communication system enabling ship-to-ship and ship-to-shore information exchange via a multi-hop network composed of onshore base stations, maritime vessels and other transit elements such as buoys.
In the paper, the idea of a heterogeneous wireless maritime system is presented. Details of the proposed netBaltic node architecture are described highlighting the solutions introduced in the project as a response to specific maritime communication requirements. Numerical results of communication area coverage are presented for four different scenarios utilizing different wireless transmission technologies. In particular, they indicate that when using appropriate wireless communication solutions, the number of vessels being able to connect to Internet is significantly increased as compared to traditional wireless systems (capable of one-hop communication) from 14% for short-range transmission technologies up to as high as 127% in case when relatively long-range transmission technologies are employed within the system.
Network communications and the Internet pervade our daily activities so deeply that we strongly depend on the availability and quality of the services they provide. For this reason, natural and technological disasters, by affecting network
and service availability, have a potentially huge impact on our daily lives. Ensuring adequate levels of resiliency is hence a key issue that future network paradigms, such as 5G, need to address.
This paper provides an overview of the main avenues of research on this topic within the context of the RECODIS COST Action.
This paper gives an overview of the most important
issues on resilience and security in Software Defined Networking
Communication networks have become a fundamental part of many critical infrastructures, playing an important role in information delivery in various failure scenarios triggered e.g., by forces of nature (including earthquakes, tornados, fires, etc.), technology-related disasters (for instance due to power blackout), or malicious human activities. A number of recovery schemes have been defined in the context of network resilience (with the primary focus on communication possibility in failure scenarios including access to a particular host, or information exchange between a certain pair of end nodes). However, because end-users are becoming more and more interested in information itself (regardless of its physical location in the network), it is appropriate to complement the well-defined framework of network resilience with one that addresses information resilience, and to introduce definitions of relevant disciplines and measures, as proposed in this paper.
Internet designed over 40 years ago was originally focused on host-to-host message delivery in a best-effort manner. However, introduction of new applications over the years have brought about new requirements related with throughput, scalability, mobility, security, connectivity, and availability among others. Additionally, convergence of telecommunications, media, and information technology was responsible for transformation of the Internet into an integrated system enabling accessing, distributing, processing, storing, and managing the payload of these messages.
Users are now visibly more interested in receiving / accessing information independently of the network location of its host. This consideration in turn revived the interest in named data-driven networking (a.k.a. Information-Centric Networking - ICN). Instead of assuming that networks are limited to the manipulation of network locator space, the basic assumption underneath is that information can be named, addressed, and matched independently of its network location leaving in turn the possibility to match message delivery delay requirements.
In this paper, we summarize our research conducted in order to bring a completely different view / perspective of network resilience, originally defined as the ability of a network to assure an acceptable level of service in the face of various faults and challenges to normal operation. That is, instead of maintaining network reachability independently of its actual utility to the “end-points”, our research aimed at exchanging and confronting the key principles that would enable an information-driven resilience (networked) scheme. More precisely, knowing that the user utility function is mainly driven nowadays by information-related criteria such as accessibility (reachability), how to design network resilience schemes that would be directed toward that goal. The main challenge is thus: can one design resilience schemes that combine maximization of end-point utility function and minimization of the network-related cost?
Power network resilience is increasingly dependent on communication networks. Besides traditional generation, power networks need to accommodate increasingly high penetration levels of dispersed micro generation, mostly based on renewable sources, and increasing and challenging demand, such as electric vehicles. At the same time the deployment of enabling technologies throughout the power grid makes available new demand resources and storage capacity. These resources have to be jointly managed for efficient and resilient operation. Therefore a resilient communication network is mandatory for the smart control of these different resources. Communication networks in turn also rely on the power networks in spite of some power backup that they may have. This interdependence is especially critical in bad weather conditions where both networks can be severely affected, even more when they strongly depend on each other. This work describes ongoing research related with the interdependence between both networks regarding resilience, cascading failure effects, applicable models and simulation techniques.
Redakcja naukowa materiałów konferencji ITST 2017
Utilization of alternate communication paths is a common technique to provide protection of transmission against failures of network nodes/links. However, a noticeable delay is encountered when calculating the relevant sets of disjoint paths using the available algorithms (e.g., using Bhandari’s approach). This, in turn, may have a serious impact on the ability of a network to serve dynamic demands (i.e., characterized by a relatively short duration time). To provide a solution to this problem, in this article we introduce an approach to pre-compute the sets of disjoint paths in advance to be able to start serving the demands shortly after their arrival. Our approach is based on the observation that the issue of establishing a set of node-disjoint paths is equivalent to the problem of determining the cheapest cycle in the network topology traversing the end nodes of a demand. In particular, we propose a generalization of this scheme assuming that any pair of node-disjoint paths can be obtained by means of merging a number of basic cycles defined for a network topology. A new method to calculate the cheapest end-to-end cycles based on the so called basic cycles is introduced, which, as verified for real network topologies, reduces up to 70% the time needed to establish node-disjoint paths (compared with the results obtained for the reference Bhandari’s scheme).
This article presents a new approach related with end-to-end routing, which, owing to quantum-inspired mecha-nisms of prediction of availability of network resources, results in improved blocking probability of incoming requests to establish transmission paths. The proposed scheme has been analyzed for three network topologies and several scenarios of network load. Obtained results show a significant (even twofold) reduction of blocking probability in comparison to results characteristic to the reference solution.