This article talks about the VNF LCM Emulator that has been developed by the ETSI Industry Specification Group for Network Functions Virtualization (ISG NFV) and its Solutions (SOL) Working Group with an aim to facilitate a “try-and-learn” approach to understanding lifecycle management (LCM) of Virtual Network Functions (VNFs)


Network Functions Virtualization (NFV) has transformed the Telco core networks over the past few years. The traditional, monolithic networking nodes have been replaced by Virtualised Network Functions (VNFs) running on commercial off-the-shelf (COTS) hardware using Cloud Computing technologies such as OpenStack, Kubernetes, etc. Management and orchestration components are used for managing the lifecycle of these VNFs in large-scale, fully automated NFV cloud deployments.

These components are crucial in realizing a move toward zero-touch service orchestration and fully automated network management. Gaining insights into how these management and orchestration components work; how they communicate internally; and which APIs they expose for crucial lifecycle management operations become all too important for developers and researchers working on different parts of the NFV Cloud stack in order to develop standards-conformant NFV products and solutions.

As part of its continuous efforts for promoting interoperability by enabling the adoption of standard specifications, the ETSI Industry Specification Group for Network Functions Virtualisation (ISG NFV) and its Solutions (SOL) Working Group have developed a “VNF LCM Emulator” with an aim to facilitate a better understanding of NFV Management and Orchestration (NFV-MANO)  by giving insight into how an NFV Orchestrator (NFVO) and a Virtualised Network Function Manager (VNFM) intercommunicate for VNF lifecycle management (LCM).

The VNF LCM Emulator is essentially a server-side implementation of the VNF LCM API, a REST API specified by ETSI using the OpenAPI description language, offering users to interact with the API producer, i.e., a VNFM emulation. Users can publicly access the tool, perform CRUD operations on VNF instances and Lifecycle Management (LCM) operations on created VNFs such as instantiate, scale, terminate, etc.

By interacting with the Emulator, users can gain a deeper understanding of VNF LCM functionality provided by the VNFM inside NFV-MANO, see what goes on inside the upper layers of the NFV stack and better understand the origin story of the messages that are exchanged between a VNFM and a Virtualised Infrastructure Manager (VIM), e.g., OpenStack, for VNF Lifecycle Management.

Combined with ETSI Group Specification ‘NFV-SOL 003’ and the associated OpenAPI descriptions, the VNF LCM Emulator can be very helpful for NFV solution developers and testers to gain a deeper understanding of VNF LCM workflows, operation sequences, standard responses and LCM operation occurrence notifications that are generated as a result of VNF LCM operations.

The VNF LCM Emulator tool is publicly available and a user guide can be found here to help users familiarize themselves with the tool through its user interface.

A short demo of how to use the VNF LCM Emulator is available. The demo covers how to instantiate a VNF instance, perform scaling, and then terminate the instance. Other LCM workflows such as scale to level, operate, change VNF flavour, etc. are also supported by the Emulator.

We encourage users to play around with the tool and perform different LCM operations on created VNF instances (dummy VNFs) to understand the interactions between VNFM and NFVO.