Network Services Chaining in the 5G Vision
IEEE Communications Magazine
A mong all the propositions for the future Internet, the fi fth generation (5G) seems to be very well positioned for becoming a reality in the near future. The 5G network aims to converge mobile and fi xed networks for supporting end-to-end applications and services. 5G will be resilient, secure, and available at all times. It is unthinkable to build such a convergent network without slicing at all levels: from the physical (slicing is enforced by the integration of several radio access
... gies) to application levels. Slicing will be achieved thanks to service chaining: data processing will become a sequence of services, potentially managed by different stakeholders. This will require more collaboration between stakeholders and/or greater openness of the off ered services. There are a number of required 5G features that pose real challenges to network service chaining: • 5G will count massive concurrent sessions, even in small cells, since mobile edge computing (MEC) is needed to be the running space for many applications with ultralow latency requirements. Thus, services in 5G should be modular (which will increase the importance of approaches such as micro-services) and distributed in the heterogeneous network. • 5G will build multi-operator heterogeneous scenarios, where management will be distributed. Therefore, management will be based on service chaining, including virtual network functions and external management applications. Two main scopes of management will be the separation between data storage and processing, and distributed management (e.g., operators' dashboards should be visible to other operators). Multi-technology and multi-operator scenarios bring important challenges to service chaining since concatenated services may be of diff erent natures and have different scopes. An example of the latter is how to localize an error in one slice that spans diff erent domains. • Agile network operations of the radio are necessary in 5G, so radio access is mainly based on virtualizing and chaining the services (cloud radio access network [C-RAN], virtualized RAN, etc.). The slicing at the physical layer and at the service layer for RAN functions makes the integration more difficult. Moreover, auto-mation in radio access services is necessary so that they may be self-managed and more dynamic (real-time management and control). • 5G requires dynamicity, understood as the capacity of offering ad hoc solutions, some of them managed by the customer. This requires fl exibility in service chaining, so new solutions must be provided. Fault, confi guration, accounting, performance, and security management should be modular and open to core and/or access ad hoc services defi ned by customers (enterprises). All these features will require the use of non-monolithic developments of service chaining, based more on reusable (micro-) services. Services will be much more abstract (developed in an out-of-context way) and service chains much more modular. In an all-layers slicing architecture such as 5G, service chain orchestration takes on significant importance. Orchestration must consider the service chain reliability, which is a challenging requirement due to multi-nature (diff erent procedures and scopes) services. Applicability of advanced service chains in 5G networks is presented in the articles of this Feature Topic. The authors' research shows foresight of networking into the future Internet for the readers. The article "Network Service Chaining in the Fog and Cloud Computing for the 5G Environment: Data Management and Security Challenges" presents a novel architecture for providing cloud and fog facilities in 5G networks. The presented architecture makes use of advances in network functions virtualization and software defi ned networking (SDN) in order to provide access to data analytics and processing in case the end user is on the move. A similar approach is defended by Datsika et al. in the article "Software Defi ned Network Service Chaining for OTT Service Providers in 5G Networks," where the authors analyze the position of overthe-top (OTT) service providers in heterogeneous environments and propose prioritization of network service chaining for OTT applications based on SDN. For their part, Qiu et al. present the problem of massive data collection with ultra-low latency and low energy consumption requirements in "A Lifetime-Enhanced Data Collecting Scheme for the Internet of Things," and propose a solution for improving routing decisions to data storage.