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- Management of the application-specific functionality of a VNF is envisioned as being outside of the scope of ETSI NFVO and VNFM functionality. ETSI NFV is currently silent about how such application level management is to be performed for a given VNF, but the assumption seems to be that it will be performed by OSS/BSS (e.g., SM/NM) or EM. This can be seen by the lack of specification of the EM to VNF interactions in Fig 5-1 below, as well as in the delegation of application configuration to the EM in the highlighted portions of the figure labeled B.3.2.2 below. (Figures taken from ETSI GS NFV-MAN 001 V1.1.1, 2014-12).
- In other words, it seems that the ETSI NFV community took the perspective that there were already well-established systems, precedence and standards around the tools (e.g., BSS/OSS/SM/NM/EM) needed to manage traditional Network Functions (i.e., PNFs), and the need of ETSI NFV was to put standards around that which was new: how to instantiate and managed "Virtualized" Network Functions to the point that they can look to the established systems (SM/NM/EM) indistinguishable from "traditional Network Functions".
- Alternative Text: ETSI NFV is currently silent about how application level data is managed for a given VNF, but provides elements in the VNF descriptor which are intended to hold this application level data. The ETSI SOL003 Or-Vnfm interface between the NFVO and the VNFM provides mechanisms to pass this data to the VNF but alternative mechanisms such as direct communication from the OSS/BSS (e.g., SM/NM) or EM. The common alternative of using the vendor's EM is highlighted in the the figure labeled B.3.2.2 below. (Figures taken from ETSI GS NFV-MAN 001 V1.1.1, 2014-12).
- In other words, it seems that the ETSI NFV community took the perspective that there were already well-established systems, precedence and standards around the tools (e.g., BSS/OSS/SM/NM/EM) needed to manage traditional Network Functions (i.e., PNFs), and the need of ETSI NFV was to put standards around that which was new: how to instantiate and managed "Virtualized" Network Functions to the point that they can look to the established systems (SM/NM/EM) indistinguishable from "traditional Network Functions".
- Therefore, in the context of Figure B.3.2.2 above, "deployment specific parameters" should be understood as that subset of VNF configuration data that must be applied in the VNF in order to make it an endpoint capable of being managed by the non-ETSI NFV OSS/BSS/SM/NM/EM.
- Thus, an ETSI Network Function Descriptor (VNF or PNF) would be expected to formally capture only those management requirements for the "deployment aspects" of that Network Function, and not the "application aspects".
- Alternative Text: An ETSI Network Function Descriptor (VNF or PNF) would be expected to formally capture those management requirements for the "deployment aspects" of that Network Function, and optionally also formally capture the management requirements for the "application aspects" of the VNF "application".
- Similarly, an ETSI Network Service Descriptor would be expected to formally capture only those management requirements for the "deployment aspects" of that Network Service, and not the "application management aspects".
- Alternative Text: Similarly, an ETSI Network Service Descriptor would be expected to formally capture the management requirements for the "deployment aspects" of that Network Service, and optionally also the "application management aspects".
- Certain Service Providers may already have the necessary BSS/OSS/SM/NM/EM systems in place to manage the "application aspects" of an ETSI NS and associated NFs, and look to ONAP only to manage the "deployment aspects" of such a NS and NFs. Such Service Providers should have the option to have ONAP perform only the equivalent functionality that would be performed by an NFVO/VNFM given that same NSD/NFD collection. Through the principle of "least astonishment", such a Service Provider would expect to elicit such behavior from ONAP by onboarding the corresponding NSD/NFD collection into SDC without any substantial extensions to that information content needing to be entered into SDC.
- However, other Service Providers may not have or want to leverage
- Therefore, in the context of Figure B.3.2.2 above, "deployment specific parameters" should be understood as that subset of VNF configuration data that must be applied in the VNF in order to make it an endpoint capable of being managed by the non-ETSI NFV OSS/BSS/SM/NM/EM.
- Thus, an ETSI Network Function Descriptor (VNF or PNF) would be expected to formally capture only those management requirements for the "deployment aspects" of that Network Function, and not the "application aspects".
- Similarly, an ETSI Network Service Descriptor would be expected to formally capture only those management requirements for the "deployment aspects" of that Network Service, and not the "application management aspects".
- Certain Service Providers may already have the necessary BSS/OSS/SM/NM/EM systems in place for this purpose, but rather look to ONAP to manage the "application aspects" of an ETSI NS and associated NFs, and look to ONAP only to manage the "deployment aspects" of such a NS and NFs. Such Service Providers should have the option to have ONAP perform only the equivalent functionality that would be performed by an NFVO/VNFM given that same NSD/NFD collection. Through the principle of "least astonishment", such a Service Provider would expect to elicit such behavior from ONAP by onboarding the corresponding NSD/NFD collection into SDC without any substantial extensions to that information content needing to be entered into SDC.VNFs and Services. These Service Providers should have this option as ONAP was envisioned to be able to do just this, such as perform application level configuration of VNFs within the context of their Services, and to perform control loop functionality on application level telemetry. However, because the ETSI Descriptors as currently defined would not be expected to formally contain information as to the application management needs of the NS/NFs, a Service Provider that onboarded such descriptors into SDC would reasonably expect to have to provide substantial additional information content to SDC regarding the "application management aspects" of the "extended" Service and Network Functions.
- Alternative Text: However, other Service Providers may not have or want to leverage BSS/OSS/SM/NM/EM systems for this purpose, but rather look to ONAP to manage the "application aspects" of VNFs and Services. These Service Providers should have this option as ONAP was envisioned to be able to do just this, such as perform application level configuration of VNFs within the context of their Services, and to perform control loop functionality on application level telemetry.
- If the provided ETSI Descriptors
- do not formally contain information as to the application management needs of the NS/NFs, a Service Provider that onboarded such descriptors into SDC would reasonably expect to have to provide substantial additional information content to SDC regarding the "application management aspects" of the "extended" Service and Network Functions. If the the ETSI Descriptor does formally include information as to the application management needs of the NS/NFs, a Service Provider that onboarded such descriptors into SDC would reasonably expect to have SDC accept the information regarding the "application management aspects" of the NS/NFs.
- Even in the case that the Service Provider chooses to leverage ONAP's "application configuration" capabilities, that does not mean that no additional configuration of the corresponding NFs will take place "out of band", outside of the purview of ONAP. For example, after ONAP has completed its application level configuration of the VNF, it may be the case that another system or person would access the VNF to perform additional configuration, e.g., via another system's direct configuration API to the VNF, or via a URL/GUI that the VNF exposes directly as a user portal. In such a case, ONAP should remain unaware of and unconcerned (in a separation of concerns sense) with whether such configuration should or should not take place, and what specific information should be or has been configured into such VNF.
- ONAP should support the ETSI construct of "nested Services", such that one ServiceA is composed of another "inner" ServiceB. ONAP should support this construct irrespective of whether the Service Provider chose to have ONAP manage the "application aspects" of both the "inner" and "outer" Service, just one of the same, or neither. This affords the Service Provider with maximum flexibility.
- In addition to this, ONAP should support the ability to support Service nesting patterns such that management of an "inner" Service is delegated to an external manager via a southbound interface. ONAP should support various external manager types, including patterns where the external manager is another ONAP instance (e.g., from a partner Service Provider) or an ETSI NFVO.
- In order to maintain separation of concerns in such a delegation pattern, ONAP would view an "inner" nested Service as being opaque, delegating all aspects of internal management to the external manager. For example, ONAP would understand how to interact with the peer external manager to request an instance of such a delegated "inner" Service, and ONAP would know what input parameters must be supplied to the external manager as part of this request. However, ONAP should not understand how those input parameters are used by the external manager to configure that "inner" Service. Certainly ONAP should remain unaware of and unconcerned with whether an additional configuration should or should not take place outside the purview of this external manager, whether by another system's direct configuration API or via a URL/GUI exposed as a user portal. ONAP's responsibility for instantiation/configuration of such a delegated Service would end with successful handoff to the external manager.
- This separation of concerns approach should be such as to allow Service Provider to migrate management of the delegated "inner" nested Service from one external manager type to another, as long as the externally visible aspects of the "inner" nested Service (e.g., the input parameters required to request an instance of such Service) remain unchanged. E.g., a Service Provider with an ETSI NFVO/VNFM installation may want to migrate management of a NS to ONAP, or vice versa. To avoid complexity of such migration, our goal should be an architecture such that ONAP interactions across its southbound API with various external managers are adaptable to the various supported external managers.
- In light of the separation of concerns delegation approach described above, and in order to preserve the flexibility to switch between external managers, the interactions between ONAP and such adaptors on its southbound interface should be fundamentally the same irrespective of whether the external manager is an ONAP that is fully responsible for all aspects of application configuration and management of the "inner" Service, an ONAP that is responsible for some aspects of application configuration and management with other aspects being handled "out of band", or an ONAP that is responsible only for managing the "deployment aspects" of the "inner" Service. The last example being functionally equivalent to an ETSI NFVO/VNFM, it follows that ONAP interactions across its southbound API with an external manager should be fundamentally the same irrespective of whether the external manager is an ONAP or an NFVO.
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