Special issue on Software‐Defined Networking and Network Functions Virtualization for flexible network management

Abstract

Economical and operational aspects motivate the demand for fundamental changes towards more flexible network management solutions. This trend is stimulated by network virtualization and Software-Defined Networks (SDNs) that emerged in recent years. These technologies allow networks to be operated and managed in a more flexible and cost-efficient manner. As an emerging topic, Network Functions Virtualization (NFV) allows even further flexibility by virtualizing network functions, for example, Dynamic Host Configuration Protocol, Point to Point Protocol over Ethernet, Firewalls or Deep Packet Inspection from dedicated hardware to software components running on commodity hardware. Virtualized network functions are appealing to network operators because they can be migrated and flexibly adapted to current demands. To this end, the goal of this special issue of the International Journal on Network Management (IJNM) on ‘SDN/NFV for Flexible Network Management’ is to address the newly achieved flexibility in network management, particularly for NFV, which opens a set of currently unresolved key questions concerning (i) techno-economic aspects, (ii) security (iii), reliability and (iv) performance. The following key questions are currently very relevant: How to operate virtualized network functions in a reliable manner by providing redundancy and load balancing? Can virtualized network functions provide performance guarantees required for network operations, and how can such virtualized services be benchmarked and compared? Where should network functions be placed to optimize the network subject to different design criteria? How can services be efficiently orchestrated? How can network monitoring in such flexible networks be used to dynamically manage them? A total of 22 submissions were received for this special issue, for which we wish to thank all authors. After extensive review and discussion, four papers were finally selected for publication. The authors of these papers were given the time to update their paper and take thoroughly the review comments and suggestions into account. The selected four papers fall into two areas that play an important role in future programmable networks: (i) network security and (ii) techno-economic analysis of a SDN/NFV-based architectures. In the first area on network security, Röpke et al. (On Network Operating System Security) present an approach to securing the network operating system or SDN controller from malicious third-party applications with the use of sandboxing and access control policies. They motivate the need for their work by presenting selected experiments that show the potential impact that malicious programs could have on a number of contemporary OpenFlow controllers. Experimental results are shown that indicate the authors' solution is effective at mitigating the demonstrated threats and has minimal impact on performance. This paper is complemented by the work of Basile et al. (Inter-function Anomaly Analysis for Correct SDN/NFV Deployment), which contributes a methodology for middlebox/forwarding rule anomaly detection and resolution. This aspect has become relevant again with the recent introduction of SDN/NFV, which allows network operators to flexibly instantiate new middleboxes and thus impact pre-existing rules. In the second area focusing on techno-economic analyses, Zhang et al. (Cost Efficiency of Mobile in-Network Caching) investigate the cost efficiency of in-network caching in an SDN-based LTE network. Network and gateway load reductions are estimated using simulations, which are then used as input for a cost model. In addition to the load reductions, the authors derive realistic estimates for the overall costs of in-network caching. The cost estimates are based on information on capital expenditures and operational expenditures gathered through interviews with technology experts. The work of Zhang et al. thus provides a novel angle that enriches and augments related work. This study is complemented by the work of Naudts et al. (How Can a Mobile Service Provider Reduce Costs with Software-Defined Networking and Network Function Virtualization) that presents a complete cost comparison of legacy Evolved Packet Core versus SDN/NFV-enabled Evolved Packet Core. In their work, the authors show that SDN/NFV enables network operators to run their networks in a more cost-efficient manner. The guest editors of this special issue would like to express their thanks to the authors who submitted their papers as well as to the reviewers for the effort they have spent to provide highly qualified reviews. Moreover, the editors would like to extend their gratitude to the editorial board of IJNM, and in particular to James Won-Ki Hong and Filip De Turck for the great opportunity to serve as Guest Editors for this special issue on SDN/NFV for Flexible Network Management. Finally, the editors wish to acknowledge support in parts by the European Union (FP7/#317846, SmartenIT, H2020/#644866, SSICLOPS) and the DFG as part of the CRC 1053 MAKI, as well as the expertise provided by members of these projects from which the editors have benefited.