Integrated NFV/SDN Architectures: A Systematic Literature Review

ion (one GNF Agent per device) C lo u d S e rv er Fig. 7. The GNF platform [47]. In addition, Sonkoly et al. (2015) [35] extended the UNIFY architecture (see Section 5.1) to create a service function chaining control plane. This solution aims to support SFC in distributed cloud ACM Computing Surveys, Vol. 0, No. 0, Article 0. Publication date: 0000. Integrated NFV/SDN Architectures: A Systematic Literature Review 0:15 scenarios, where VNFs from the same SFC can run in di erent NFVI-PoPs. A prototype framework, called Extensible Service Chain Prototyping Environment (ESCAPE), was implemented in Python on top of a POX Controller. This prototype works with two domains in the Infrastructure Layer (IL): Cloud and OpenFlow. The OpenStack Cloud Platform [33] and the OpenDaylight Controller [34] perform the management of Cloud domains while VNFs are deployed as KVM virtual machines (running a Click process). The OpenFlow domains handle transport networks with Linux nodes running Open vSwitches (OpenFlow support). The POX Controller [49] (network management) and the NETCONF/YANG (VNF management) manage these domains while VNFs are deployed as distinct processes (Linux cgroups) and run network functions implemented in Click Modular Router. Finally, Deng et al. (2015) [43] proposed the VNGuard framework that uses NFV to provide fast and dynamic virtual rewalls in a cloud environment, for the protection of Virtual Networks. Aimed at considering VN’s changeable topology (VMs dispersion and migration), this framework uses SDN to provide fast and exible tra c steering to virtual rewalls. They used OpenStack as a VIM and ClickOS for VNF development. CloudLab6 is a testbed that provides an Infrastructure as a Service (IaaS) for cloud-based experiments. 5.4 Virtualized Customers Premises Equipment (vCPE) CPE (Customers Premises Equipment) means any equipment (router, modem, etc.) within the customer domain that receives a communication service. CPEs have been a barrier to the current goals of both telecommunications companies and service providers, due to the high cost of maintenance, management di culties, and the impossibility of remote upgrades. As an alternative, a solution is the CPE virtualization using an NFV architecture, also known as Virtualized CPE (vCPE) [50]. According to an IHS Markit Survey7, published in 2016, 100% of consulted service providers said they intend to deploy NFV at some point. 81% expect to roll out this deployment by 2017. Most service providers (more than 80%) have a preference for deploying vCPE. vCPE is a service in which some or all of the functions associated with CPE are virtualized [50]. One of the main problems related to CPEs virtualization is how to instantiate network services in distributed infrastructures (using multiple NFVI-PoPs) [51]. In this type of scenario (see Figure 8), also called Distributed NFV [52], the VNFs are placed either in the service provider Cloud platform (Cloud CPE) or the on-premise CPE, depending on where they are most e cient regarding latency, available resources, etc. SDN has been the technology adopted to implement the communication management of di erent scenarios (e.g., Cloud, CPE, and WAN) to provide Distributed NFV. Data Center Customer Site