To help guide the reader, this glossary provides an introduction to the terminology used within this document. These definitions are, with a few exceptions, based on the ETSI GR NFV 003 V1.5.1 [1] definitions. In a few cases, they have been modified to avoid deployment technology dependencies only when it seems necessary to avoid confusion.

Software Layer Terminology

  • Cloud Infrastructure: A generic term covering NFVI, IaaS and CaaS capabilities - essentially the infrastructure on which a Workload can be executed.

Note: NFVI, IaaS and CaaS layers can be built on top of each other. In case of CaaS some cloud infrastructure features (e.g.: HW management or multitenancy) are implemented by using an underlying IaaS layer.

  • Cloud Infrastructure Profile: The combination of the Cloud Infrastructure Software Profile and the Cloud Infrastructure Hardware Profile that defines the capabilities and configuration of the Cloud Infrastructure resources available for the workloads.

  • Cloud Infrastructure Software Configuration: a set of settings (Key:Value) that are applied/mapped to cloud infrastructure SW deployment.

  • Cloud Infrastructure Software Profile: defines the behaviour, capabilities and metrics provided by a Cloud Infrastructure Software Layer on resources available for the workloads.

  • Cloud Native Network Function (CNF): A cloud native network function (CNF) is a cloud native application that implements network functionality. A CNF consists of one or more microservices. All layers of a CNF is developed using Cloud Native Principles including immutable infrastructure, declarative APIs, and a “repeatable deployment process”.

    Note: This definition is derived from the Cloud Native Thinking for Telecommunications Whitepaper (, which also includes further detail and examples.

  • Compute flavour: defines the sizing of the virtualised resources (compute, memory, and storage) required to run a workload.

    Note: used to define the configuration/capacity limit of a virtualised container.

  • Hypervisor: a software that abstracts and isolates workloads with their own operating systems from the underlying physical resources. Also known as a virtual machine monitor (VMM).

  • Instance: is a virtual compute resource, in a known state such as running or suspended, that can be used like a physical server. Used interchangeably with Compute Node and Server.

    Note: Can be used to specify VM Instance or Container Instance.

  • Network Function (NF): functional block or application that has well-defined external interfaces and well-defined functional behaviour.

  • Within NFV, a Network Function is implemented in a form of Virtualised NF (VNF) or a Cloud Native NF (CNF).

  • Network Function Virtualisation (NFV): The concept of separating network functions from the hardware they run on by using a virtual hardware abstraction layer.

  • Network Function Virtualisation Infrastructure (NFVI): The totality of all hardware and software components used to build the environment in which a set of virtual applications (VAs) are deployed; also referred to as cloud infrastructure.

    Note: The NFVI can span across many locations, e.g. places where data centres or edge nodes are operated. The network providing connectivity between these locations is regarded to be part of the cloud infrastructure. NFVI and VNF are the top-level conceptual entities in the scope of Network Function Virtualisation. All other components are sub-entities of these two main entities.

  • Network Service (NS): composition of Network Function(s) and/or Network Service(s), defined by its functional and behavioural specification, including the service lifecycle.

  • Software Defined Storage (SDS): An architecture which consists of the storage software that is independent from the underlying storage hardware. The storage access software provides data request interfaces (APIs) and the SDS controller software provides storage access services and networking.

  • Virtual Application (VA): A general term for software which can be loaded into a Virtual Machine.

    Note: a VNF is one type of VA.

  • Virtual CPU (vCPU): Represents a portion of the host’s computing resources allocated to a virtualised resource, for example, to a virtual machine or a container. One or more vCPUs can be assigned to a virtualised resource.

  • Virtual Machine (VM): virtualised computation environment that behaves like a physical computer/server.

    Note: A VM consists of all of the components (processor (CPU), memory, storage, interfaces/ports, etc.) of a physical computer/server. It is created using sizing information or Compute Flavour.

  • Virtual Network Function (VNF): a software implementation of a Network Function, capable of running on the Cloud Infrastructure.

    • VNFs are built from one or more VNF Components (VNFC) and, in most cases, the VNFC is hosted on a single VM or Container.

  • Virtual resources:

    • Virtual Compute resource (a.k.a. virtualisation container): partition of a compute node that provides an isolated virtualised computation environment.

    • Virtual Storage resource: virtualised non-volatile storage allocated to a virtualised computation environment hosting a VNFC.

    • Virtual Networking resource: routes information among the network interfaces of a virtual compute resource and physical network interfaces, providing the necessary connectivity.

  • Workload: an application (for example VNF, or CNF) that performs certain task(s) for the users. In the Cloud Infrastructure, these applications run on top of compute resources such as VMs or Containers. Most relevant workload categories in the context of the Cloud Infrastructure are:

    • Data Plane Workloads: that perform tasks related to packet handling of the end-to-end communication between applications. These tasks are expected to be very I/O and memory read/write operations intensive.

    • Control Plane Workloads: that perform tasks related to any other communication between NFs that is not directly related to the end-to-end data communication between applications. For example, this category includes session management, routing or authentication.

    • Storage Workloads: that perform tasks related to disk storage (either SSD or HDD or other). Examples range from non-intensive router logging to more intensive database read/write operations.

Hardware Layer Terminology

  • Cloud Infrastructure Hardware Configuration: a set of settings (Key:Value) that are applied/mapped to Cloud Infrastructure HW deployment.

  • Cloud Infrastructure Hardware Profile: defines the behaviour, capabilities, configuration, and metrics provided by a cloud infrastructure hardware layer resources available for the workloads.

    • Host Profile: is another term for a Cloud Infrastructure Hardware Profile.

  • CPU Type: A classification of CPUs by features needed for the execution of computer programs; for example, instruction sets, cache size, number of cores.

  • Hardware resources: Compute/Storage/Network hardware resources on which the cloud infrastructure platform software, virtual machines and containers run on.

  • Physical Network Function (PNF): Implementation of a network function via tightly coupled dedicated hardware and software system.

    Note: This is a physical cloud infrastructure resource with the NF software.

  • Simultaneous Multithreading: Simultaneous multithreading (SMT) is a technique for improving the overall efficiency of superscalar CPUs with hardware multithreading. SMT permits multiple independent threads of execution on a single core to better utilise the resources provided by modern processor architectures.

Operational and Administrative Terminology

  • Cloud service user: Natural person, or entity acting on their behalf, associated with a cloud service customer that uses cloud services.

    Note Examples of such entities include devices and applications.

  • Compute Node: An abstract definition of a server. Used interchangeably with Instance and Server.

    Note: A compute node can refer to a set of hardware and software that support the VMs or Containers running on it.

  • External Network: External networks provide network connectivity for a cloud infrastructure tenant to resources outside of the tenant space.

  • Fluentd ( An open source data collector for unified logging layer, which allows data collection and consumption for better use and understanding of data. Fluentd is a CNCF graduated project.

  • Kibana: An open source data visualisation system.

  • Multi-tenancy: feature where physical, virtual or service resources are allocated in such a way that multiple tenants and their computations and data are isolated from and inaccessible by each other.

  • Prometheus: An open-source monitoring and alerting system.

  • Quota: An imposed upper limit on specific types of resources, usually used to prevent excessive resource consumption by a given consumer (tenant, VM, container).

  • Resource pool: A logical grouping of cloud infrastructure hardware and software resources. A resource pool can be based on a certain resource type (for example, compute, storage and network) or a combination of resource types. A Cloud Infrastructure resource can be part of none, one or more resource pools.

  • Service Assurance (SA): collects alarm and monitoring data. Applications within SA or interfacing with SA can then use this data for fault correlation, root cause analysis, service impact analysis, SLA management, security, monitoring and analytic, etc.

  • Tenant: cloud service users sharing access to a set of physical and virtual resources ITU (Y.3500: Information technology - Cloud computing - Overview and vocabulary).

    Note Tenants represent an independently manageable logical pool of compute, storage and network resources abstracted from physical hardware.

  • Tenant Instance: refers to a single Tenant.

  • Tenant (Internal) Networks: Virtual networks that are internal to Tenant Instances.

Other Referenced Terminology

  • Anuket Assured Program (AAP): An open source, community-led program to verify compliance of the telecom applications and the cloud infrastructures with the Anuket specifications.

  • Carrier Grade: Carrier grade refers to network functions and infrastructure that are characterised by all or some of the following attributes: High reliability allowing near 100% uptime, typically measured as better than “five nines”; Quality of Service (QoS) allowing prioritization of traffic; High Performance optimized for low latency/packet loss, and high bandwidth; Scalability to handle demand growth by adding virtual and/or physical resources; Security to be able to withstand natural and man-made attacks.

  • Monitoring (Capability): Monitoring capabilities are used for the passive observation of workload-specific traffic traversing the Cloud Infrastructure. Note, as with all capabilities, Monitoring may be unavailable or intentionally disabled for security reasons in a given cloud infrastructure instance.

  • NFV Orchestrator (NFVO): Manages the VNF lifecycle and Cloud Infrastructure resources (supported by the VIM) to ensure an optimised allocation of the necessary resources and connectivity.

  • Platform: A cloud capabilities type in which the cloud service user can deploy, manage and run customer-created or customer-acquired applications using one or more programming languages and one or more execution environments supported by the cloud service provider. Adapted from ITU (Y.3500: Information technology - Cloud computing - Overview and vocabulary).

    Note: This includes the physical infrastructure, Operating Systems, virtualisation/containerisation software and other orchestration, security, monitoring/logging and life-cycle management software.

  • Vendor Implementation: A commercial implementation of a cloud platform.

  • Virtualised Infrastructure Manager (VIM): Responsible for controlling and managing the Network Function Virtualisation Infrastructure compute, storage and network resources.