OpenVAS is a framework of several services and tools offering a comprehensive and powerful vulnerability scanning and vulnerability management solution. The powerful and comprehensive solution is available as Free Software and maintained on a daily basis. The manager controls the Scanner via OTP (OpenVAS Transfer Protocol) and itself offers the XML-based, stateless OpenVas Management Protocol (OMP) All intelligence is implemented in the Manager so that it is possible to implement various lean clients that will behave consistently. The Manager also controls a SQL database where all configuration and scan result data is centrally stored.
Source: https://thehackernews.com/2011/10/openvas-advanced-open-source.html