Topology and Orchestration Specification for Cloud Applications (TOSCA) and Netconf/YANG are standards for setting up virtual networks and/or physical networks using data models that can help with the orchestration of network-based services. The industry often thinks in terms of using TOSCA vs. Netconf/YANG for configuring networks for cloud applications, but the truth is these tools can often work together and have slightly different roles.
TOSCA was put together by industry group OASIS, to enable the portability of cloud applications and related IT services for telecom operators. Netconf and YANG are standards developed at the Internet Engineering Task Force (IETF).
TOSCA vs. Netconf/YANG
TOSCA targets the orchestration of cloud applications. In the service provider world, it can also be used to configure network functions virtualization (NFV) applications. TOSCA abstracts configuration data away from specific hardware or services to make cloud services more interoperable and portable.
Users of TOSCA believe it can deliver portability of services that are TOSCA compatible. The data model also enables easier migration of applications, bursting of service levels, and portability among multiple clouds or hybrid cloud platforms. The broad application of such standards can benefit consumers while enabling growth of the cloud market as a whole.
NETCONF is a protocol that works with YANG, a network data modeling language defined by the IETF. Think of NETCONF as the protocol that operates on data modeled with YANG. Netconf provides a runtime API for virtual network functions (VNFs) and communications directly with the element management systems (EMSs) of physical networking hardware. Therefore, Netconf and YANG, typically used together, are perceived as having a strength in configuring physical networking hardware.
TOSCA, Netconf/YANG, and NFV
TOSCA can also be used to configure applications being used as VNFs in the ETSI model for NFV. However, other configuration information may be needed in a service provider network, such as how the VNF interacts with operation support systems (OSSs) and business support systems (BSSs). Netconf/YANG can also be used in NFV, providing a way of sharing information between the OSSs and the network devices using the EMS.
TOSCA and Netconf/YANG may in many cases work together. For example, TOSCA could hand instructions to Netconf/YANG to define the configuration of hardware being used for an application. The OSS may also use Netconf/YANG to communicate with the EMSs, which coordinate physical hardware.
To summarize, it’s best to think of TOSCA as an applications orchestration tool that works primarily with software, while Netconf/YANG provides a direct interface to configuring physical hardware via the EMS. Both TOSCA and Netconf/YANG can be used in different network application scenarios, sometimes in complementary roles. They can both be used to improve the automation needed to set up and orchestrate new cloud-based applications.