Wrapping up the NFVI layer, we’ll move on to the Virtualized Infrastructure Manager (VIM). The VIM manages the NFVI and the serves as a conduit for control-path interaction between VNFs and NFVI. Broadly speaking, the VIM inventories, provisions, de-provisions and manages virtual compute, storage and networking while also communicating with the underlying physical resources. The VIM is responsible for operational aspects such as logs, metrics, alerts, root cause analysis, policy enforcement, service assurance etc. It is also responsible for interacting with the orchestration layer (MANO) and SDN controller (for this report we are breaking out the SDN controller as a distinct item separate from the VIM).
Unlike the NFVI which consists of numerous technologies that can be assembled independently, the VIM comes in the form of complete software stacks. There are two main VIM software stacks prevalent in NFV: OpenStack® and VMware vRealize (1). Other candidates like CloudStack have not been prominent in the last 2-3 years in the NFV space.
VIM – OpenStack
To get a handle on OpenStack, which is growing in popularity among NFV deployments at carriers worldwide, let’s see what the OpenStack Foundation, which shepherds the development and growth of the software stack says about OpenStack:
OpenStack is open source software for managing telecommunications infrastructure for NFV, 5G, IoT and business applications. Global telecoms including AT&T, China Mobile, Orange, NTT DOCOMO and Verizon deploy OpenStack as an integration engine with APIs to orchestrate bare metal, virtual machine and container resources on a single network. OpenStack is a global community of more than 70,000 individuals across 183 countries supported by the OpenStack Foundation.
OpenStack is one of the largest open source projects in the world, and is seven years old on its 15th release, Ocata. Ocata was developed by 1,925 community members from 285 organizations. To give a sense of the expansive scope, OpenStack has 6 core projects and 54 optional services. Beyond these 60 projects, there are numerous “community” projects that are affiliated with OpenStack. OpenStack is well represented by a vibrant community with 8 platinum members, 21 gold members, 125 corporate sponsors and over 500 supporting organizations. The governance of the OpenStack Foundation allows for transparency and meritocracy; and many of the DevOps related infrastructure innovations by the OpenStack community have been copied by many other projects. However, the decentralized nature of the organization also results in a lack of consistency between projects, inadequately staffed projects and increasing complexity of the overall stack.