A Survey on Fault Management in Software-Defined Networks

Software-defined networking (SDN) is an emerging paradigm that has become increasingly popular in recent years. The core idea is to separate the control and data planes, allowing the construction of network applications using high-level abstractions that are translated to network devices through a southbound interface. SDN architecture is composed of three layers: 1) infrastructure layer, responsible exclusively for data forwarding; 2) control layer, which maintains the network view and provides core network abstractions; and 3) application layer, which uses abstractions provided by the control layer to implement network applications. SDN provides features, such as flexibility and programmability, that are key enablers to meet current network requirements (e.g., multi-tenant cloud networks and elastic optical networks). However, along with its benefits, SDN also brings new issues. In this survey we focus on issues related to fault management. Different fault management threat vectors are introduced by each layer, as well as by the interface between layers. Nevertheless, besides addressing fault management issues of its architecture, SDN also must handle the same problems faced by legacy networks. However, programmability and centralized management might be used to provide flexibility to deal with those issues. This paper presents an overview of fault management in SDN. The major contributions of this paper are as follows: 1) identification of the main fault management issues in SDN and classification according to the affected layers; 2) survey of efforts that address those issues and classification according to the affected planes, issues concerned, general approaches, and features; and 3) discussion about trade-offs of different approaches and their suitability for different scenarios.