att_abstract={{Network Functions Virtualization (NFV) is an emerging technology that can significantly improve the flexibility of network service provisioning and offer potential cost savings. However, when virtualizing network functions and moving them from proprietary hardware appliances to commercial servers and switches, how to guarantee their reliability and availability becomes a major concern of network  operators, especially for efficient network and service management. Moreover, the decoupling of software implementation from underlying hardware also shifts more resiliency demands to network operators; while traditionally vendors are more responsible for the resiliency of the bundled network equipment. In this article, we explain the resiliency requirements for Virtual Network Functions (VNFs) in order to provide carrier grade services, summarize the existing solutions in the literature, highlight several research challenges, and present a concrete case study to demonstrate how to decompose a type of virtual router and thus enhance its resiliency. }},
	att_authors={bh1729, vg7777, kk0563, as1818},
	att_copyright_notice={{This version of the work is reprinted here with permission of IEEE for your personal use. Not for redistribution. The definitive version was published in IEEE Communications Magazine  {{, 2017-07-01}}
	att_tags={Network functions virtualization,  virtual network functions,  resiliency,  network management,  reliability,  availability},
	author={Bo Han and Vijay Gopalakrishnan and Gnanavelkandan Kathirvel and Aman Shaikh},
	institution={{IEEE Communications Magazine }},
	title={{On the Resiliency of Virtual Network Functions}},