9 The term refers to network service providers and Virtual Network
10 Function (VNF) providers.
13 The term refers to a subscriber of the Operator's services.
16 The term refers to a service provided by an Operator to its
17 end-users using a set of (virtualized) Network Functions
19 Infrastructure Services
20 The term refers to services provided by the NFV Infrastructure to the VNFs
21 as required by the Management & Orchestration functions and especially the VIM.
22 I.e. these are the virtual resources as perceived by the VNFs.
25 The term refers to an upgrade that results in no service outage
29 The term refers to an upgrade strategy, which upgrades a node or a subset
30 of nodes at a time in a wave style rolling through the data centre. It
31 is a popular upgrade strategy to maintain service availability.
33 Parallel Universe Upgrade
34 The term refers to an upgrade strategy, which creates and deploys
35 a new universe - a system with the new configuration - while the old
36 system continues running. The state of the old system is transferred
37 to the new system after sufficient testing of the new system.
39 Infrastructure Resource Model
40 The term refers to the representation of infrastructure resources,
41 namely: the physical resources, the virtualization
42 facility resources and the virtual resources.
45 The term refers to a piece of hardware in the NFV infrastructure that may
46 also include firmware enabling this piece of hardware.
49 The term refers to a resource, which is provided as services built on top
50 of the physical resources via the virtualization facilities; in particular,
51 virtual resources are the resources on which VNFs are deployed. Examples of
52 virtual resources are: VMs, virtual switches, virtual routers, virtual disks.
54 Visualization Facility
55 The term refers to a resource that enables the creation
56 of virtual environments on top of the physical resources, e.g.
57 hypervisor, OpenStack, etc.
60 The term refers to a choreography that describes how the upgrade should
61 be performed in terms of its targets (i.e. upgrade objects), the
62 steps/actions required of upgrading each, and the coordination of these
63 steps so that service availability can be maintained. It is an input to an
64 upgrade tool (Escalator) to carry out the upgrade.
67 The duration of an upgrade characterized by the time elapsed between its
68 initiation and its completion. E.g. from the moment the execution of an
69 upgrade campaign has started until it has been committed. Depending on
70 the upgrade strategy, the state of the configuration and the upgrade target
71 some parts of the system may be in a more vulnerable state with respect to
75 The period of time during which a given service is not provided is referred
76 as the outage of that given service. If a subsystem or the entire system
77 does not provide any service, it is the outage of the given subsystem or the
78 system. Smooth upgrade means upgrade with no outage for the user plane, i.e.
79 no VNF should experience service outage.
82 The term refers to a failure handling strategy that reverts the changes
83 done by a potentially failed upgrade execution one by one in a reverse order.
84 I.e. it is like undoing the changes done by the upgrade.
87 The term refers to data persisted to a storage, so that it can be used to
88 restore the system or a given part of it in the same state as it was when the
89 backup was created assuming a cold restart. Changes made to the system from
90 the moment the backup was created till the moment it is used to restore the
91 (sub)system are lost in the restoration process.
94 The term refers to a failure handling strategy that reverts the changes
95 done, for example, by an upgrade by restoring the system from some backup
96 data. This results in the loss of any change and data persisted after the
97 backup was been taken. To recover those additional measures need to be taken
98 if necessary (e.g. rollforward).
101 The term refers to a failure handling strategy applied after a restore
102 (from a backup) opertaion to recover any loss of data persisted between
103 the time the backup has been taken and the moment it is restored. Rollforward
104 requires that data that needs to survive the restore operation is logged at
105 a location not impacted by the restore so that it can be re-applied to the
106 system after its restoration from the backup.
109 The term refers to an upgrade in which an earlier version of the software
110 is restored through the upgrade procedure. A system can be downgraded to any
111 earlier version and the compatibility of the versions will determine the
112 applicable upgrade strategies and whether service outage can be avoided.
113 In particular any data conversion needs special attention.
119 The term is an abbreviation for Network Function Virtualization
120 Infrastructure; sometimes it is also referred as data plane in this
121 document. The NFVI provides the virtual resources to the virtual
122 network functions under the control of the VIM.
125 The term is an abbreviation for Virtual Infrastructure Manager;
126 sometimes it is also referred as control plane in this document.
127 The VIM controls and manages the NFVI compute, network and storage
128 resources to provide the required virtual resources to the VNFs.