# Deploying CPU-Intensive Applications on MEC in NFV Systems: The Immersive Video Use Case
## 1 Introduction  
The recent rise of data-intensive services, such as video streaming, social networking, and gaming, has triggered an explosion of mobile traffic, with the specific need to achieve higher data rates per user. Concurrently, novel business segments--e.g., automotive, smart manufacturing, and healthcare--have contributed significantly to the demand for ultra-reliable low-latency and massive machine-type communications. Forthcoming 5 th Generation (5G) mobile networks are being designed to satisfy such requirements, and to take advantage of the convergence of the telecom world with the Cloud Computing paradigm [1; 2]. The adoption of Cloud Computing in communication infrastructures addresses the need of telecom operators to cut operational costs, improve flexibility, and reduce service deployment time. In this context, Network Function Virtualization (NFV) and Software-Defined Networking (SDN) play a crucial role by enabling the deployment of network services as cloud applications in large, centralized data centers, usually located in the network core [3]. On the other hand, this widely acclaimed approach can provide unsatisfactory results whenever a service requires low response times and/or high data rates, due to bottlenecks in the data-path to or from end users. Thus, pushed by the need to process data in proximity to consumers, network operators are carefully considering the deployment of Information Technology (IT) resources at the network edge, as envisioned by the Edge Computing paradigm [4]. Edge Computing makes it possible to minimize transmission delay and achieve high data rates locally. Furthermore, applications running at the edge can exploit specific real-time information provided by the Radio Access Network, such as radio link status or the geographic location of consumers [4; 5]. To promote the adoption of Edge Computing, in 2014 the European Telecommunications Standards Institute (ETSI) launched the Mobile Edge Computing Industry Specification Group (ISG) Mobile Edge Computing (renamed Multi-access Edge Computing in 2016), which is releasing guidelines for the deployment of MEC systems in 4G and, in perspective, in 5G networks [6; 7; 8]. In this context, a topic of significant interest is the integration of MEC with NFV. Mobile network operators, in fact, aim to consolidate Virtual Network Functions (VNFs) and Mobile Edge (ME) apps on top of the same infrastructure, to maximize their return of investment in virtualization technology [9; 10]. However, despite the considerable amount of work already done, the development of an MEC in an NFV system can still present many challenges, some of which (to the best of the authors' knowledge) have not been adequately addressed yet. The first difficulties typically encountered--as results clearly from Reference [10]--are at the architectural level, due to some known problems in integrating the MEC and NFV frameworks in accordance with the corresponding reference standards. Presently, ETSI Standardization groups focus on a list of fourteen MEC in NFV integration open issues, some of which could even require changes to the current MEC specifications [10]. Nonetheless, industrial players need to find practical solutions to such problems in the short term, to rapidly respond to the rising demand for commercial ME systems. A second important aspect concerning MEC is how end users can effectively access the services offered by ME apps. Recently, consumers' preferences have shown a shift from standard voice calls and text messaging to advanced video activities and social networking, carried out through their tablets or smartphones [11; 12]. During sporting events, concerts, or in touristic locations, consumers increasingly often wish to originate and share media contents in groups of peers, rather than merely receiving them from a centralized media distribution system.