ONVIF profiles make it easy to recognize how ONVIF-conformant devices and clients are compatible with one another. An ONVIF profile has a fixed set of features that must be supported by a conformant device and client.
It ensures that a client conforming to Profile S, for example, will work with another device that also conforms to Profile S. There are also conditional features, which are features that shall be implemented by an ONVIF device or ONVIF client if it supports that feature in any way, including any proprietary way. The underlying functions of the features included in a profile are defined in the ONVIF Network Interface Specifications.
Some clients and devices can support more than one ONVIF profile. For instance, a network camera with local storage can conform to both Profile S and G.
Conformance to profiles is the only way that ensures compatibility between ONVIF conformant products, therefore, only registered products with conformance to a profile are considered to be ONVIF conformant.