The fifth-generation (5G) mobile networks are expected to bring higher capacity, higher density of mobile devices, lower battery consumption and improved coverage. 5G entails the convergence of wireless and wired communications in a unified and efficient architecture. Mobile nodes, as defined in fourth-generation era, are transformed in heterogeneous networks to make the front-haul wireless domains flexible and intelligent. This work highlights a set of critical challenges in advancing 5G networks, fuelled by the utilisation of the network function virtualisation, the software defined radio and the software defined networks techniques. Furthermore, a novel conceptual model is presented in terms of control and management planes, where the inner architectural components are introduced in detail.

Network service orchestration across heterogeneous networks needs an open marketplace where the services advertised by the providers in different domains can be purchased for short-term or long-term time scales. The authors present two design paradigms and evaluate two corresponding prototypes which provide a framework for network services to be purchased. They compare the two prototypes from the point of view of how effective they are in addressing some of the challenges posed by heterogeneous 5G networks namely programmability, scalability and innovation. They present a network service orchestration algorithm which is advertised as a network service in the marketplace.

Software-defined networking (SDN) already has an established presence in the networking industry as an emerging paradigm for designing network architectures, decoupling the control from the forwarding plane and offering a centralised way of network management. Cloud and enterprise infrastructure engineers have already adopted such techniques for building up their environments, deliberating the cost and flexibility advantages gained from this technology. However, smaller companies may choose a progressive replacement of their equipment due to operational and budget constraints. Hence, mixing equipment could lead up to hybrid SDN environments making network management even more complex. In this study, an event-based generic topology discovery algorithm, capable of providing an efficient packet discovery mechanism using existing protocols in SDN networks, is proposed. For testing and evaluation purposes, address resolution protocol and link layer discovery protocol are being used to extract the information needed and reconstruct the topology to the controller. Implementation is accomplished using Internet Engineering Task Force's ForCES framework.

Secure and stable routing is a critical issue in a conventional network environment, as the control and data planes are integrated. An intelligent routing is highly essential to provide an attack free network to its intended users. The programmable software defined network is an emerging network paradigm in which the security policies and the forwarding rules are implemented in the controller via North Bound Interface. This study incorporates a cognitive neural network learning algorithm namely restricted Boltzmann machine (RBM), to detect the routing-based distributed denial of service attacks in dynamic source routing (DSR) protocol. RBM is a stochastic and unsupervised learning algorithm that self-learns the network conditions by using its reasoning capability and segregates malicious routes in the route cache using context-aware trust metrics such as reputation and energy consumption implemented in North Bound Application Programming Interface. The results show that a cognitive DSR protocol provides secure routing by increased packet delivery ratio, decreased end-to-end delay, reduced energy consumption and accurate detection of malicious routes compared with the conventional DSR protocol.

In opportunistic networks (OppNets), routing and data forwarding among mobile devices are facilitated by relays or next-hop forwarders. To guarantee end-to-end data delivery it is important to provide participation. However, in sparsely connected OppNets, it is extremely challenging to monitor the behaviour of the relays and identify selfish/malicious relays cooperating with each other in order to forge routing information or drop useful data. Cooperation enforcement schemes are seen as a lightweight alternative to conventional secure forwarding techniques that involve cryptographically signed certificate exchanges, providing a ‘softer’ security layer to protect basic networking operations. In general, cooperation enforcement schemes fall into two broad categories: trust establishment via a reputation system and pricing or credit-based schemes. This study offers a comprehensive survey of representative cooperation enforcement schemes that exploit a reputation system. The authors analyse their distinct features, identify and discuss critical challenges that should be efficiently addressed when designing such mechanisms, indicating at the same time potential solutions and provide an informative table to display the authors’ findings. From this analysis, they examine issues and concerns surrounding the field of cooperation enforcement in OppNets, and provide guidelines and directions for future researchers.

In modern call centres 60–70% of the operational costs come in the form of the human agents who take the calls. Ensuring that the call centre operates at lowest cost and maximum efficiency involves a trade-off of the cost of agents against lost revenue and increased customer dissatisfaction due to lost calls. Modelling the performance characteristics of a call centre in terms of the agent queue alone misses key performance influencers, specifically the interaction between channel availability at the media gateway and the time a call is queued. A blocking probability at the media gateway, as low as 0.45%, has a significant impact on the degree of queuing observed and therefore the cost and performance of the call centre.

Our analysis also shows how abandonment impacts queuing delay. However, the call centre manager has less control over this than the level of contention at the media gateway. Our commercial assessment provides an evaluation of the balance between abandonment and contention, and shows that the difference in cost between the best and worst strategy is £130K per annum, however this must be balanced against a possible additional £2.98 m exposure in lost calls if abandonment alone is used.

Video content is increasingly being consumed on the move using mobile devices such as smart phones and tablets. In order to deal with the challenges of heterogeneity of network access technologies and fluctuating resources, which are inherent features of mobile communication, HTTP adaptive streaming (HAS) is becoming the default technology for online video streaming. However, little research has been carried out to better understand the impact of handover schemes of the various mobility management protocols on the video quality of HAS. In this study, the authors present a comprehensive experimental measurement of the impact of handover on three representative HAS players. First, they implement three existing mobility management protocols, MIPv6, LISP-MN and PMIPv6, on a network testbed. Using the fluid flow mobility model, the impact of frequent handover on the average video quality, the bandwidth utilisation and stability of the players was investigated. Their results show a degradation of all the observed parameters in all the reviewed players.

Cognitive radio networks (CRNs) are prone to emerging coexistence security threats such as primary user emulation attack (PUEA). Specifically, a malicious CRN may mimic licensees' [primary users (PUs)] signal characteristics to force another CRN to vacate its channels thinking that PUs have returned. While existing schemes are promising to some extent on detecting PUEAs, they are not able to prevent the attacks. In this article, the authors propose a PUEA deterrent (PUED) algorithm that can provide PUEAs' commission details: offender CRNs and attacks' time and bandwidth. There are many similarities between PUED and closed-circuit television (CCTV) in terms of: deterrence strategy, reason for use, surveillance characteristics, surveillance outcome, and operation site. According to the criminology literature, robust CCTV systems have shown a significant reduction in visible offences (e.g. vehicle theft), reducing crime rates by 80%. Similarly, PUED will contribute the same effectiveness in deterring PUEAs. Furthermore, providing PUEAs' details will prevent the network's cognitive engine from considering the attacks as real PUs, consequently avoiding devising unreliable spectrum models for the attacked channels. Extensive simulations show the effectiveness of the PUED algorithm in terms of improving CRNs' performance.

The sensor nodes of wireless sensor networks (WSNs) are usually positioned in remote or inaccessible areas and hence the physical maintenance such as battery replacement is more difficult. One of the core challenges of WSN is to increase the network life time, meaning that the efficiency of power utilisation should be the maximum. The major reasons for high power consumption are drawn out transmission path to reach sink, work load add-ons on nodes closer to storage medium, and the energy necessary for storage. This study proposes a novel method of data storage and retrieval for WSN environment to improve the network lifetime by minimising the energy consumption. The proposed method accomplishes this milestone using four novel algorithms, namely weighted optimum storage-node placement(SNP), efficient and energetic wireless recharging, efficient rule-based node rotation and critical-state-data passing. The areas of influence of this proposed method are SNP, wireless recharging, node rotation and cooperative multi-input–multi-output clustering/routing. Simulation results claim that the proposed method multiplies the WSN topology lifetime ratio by a significant level and outperforms the earlier versions significantly.

Wireless sensor and actuator networks (WSAN) have greatly benefited from the latest development in real-time Internet of Things standardisation efforts. Specifically, the Internet Engineering Task Force Constrained Application Protocol (CoAP) is one of the preferred mechanisms that provide session transport in the context of low-power low-rate networks in general and WSAN in particular. CoAP, that relies on traditional user datagram protocol, introduces a particular mode of operation, known as non-confirmable, that minimises latency but it is highly sensitive to network packet loss. The use of forced forward error correction (FEC), although efficient at reducing packet loss, excessively increases the session throughput. The authors introduce an algorithm that dynamically manages FEC minimising application layer packet loss while keeping throughput under control. The mechanism is evaluated through an experimental framework where traditional CoAP, forced FEC CoAP and dynamic FEC CoAP implementations are compared.

Deep packet inspection (DPI) represents the major process in network intrusion detection and prevention systems. In DPI each security threat is represented as a signature, and the payload of every incoming data packet is matched against the set of current signatures. Moreover, DPI is also used for other networking applications such as packet classification, quality of service techniques, protocol identification and so on. DPI exhausts extra central processing unit and memory resources, and as a result, several attempts have been proposed to improve this process. In this study, the authors proposed a fast two-dimensional (2D) filter with low false positive (FP) rate for DPI purposes. It consists of 2D array that employs single hash function and has very low FP rate. Using this filter as an identification tool in a DPI technique will result in more accurate and higher throughput than other systems that employ Bloom (BFs) and quotient filters (QFs). Our experiments show that the proposed solution has time improvement up to 94% over others that employ BFs or QFs and the achieved average throughput is 1.8 Gbps.