Purpose and Scope The purpose of this memo is to describe an additional OPTIONAL function and feature for TWAMP [RFC5357]. The scope of the memo is limited to specifications of the following features: 1. extension of the modes of operation through assignment of a new value in the Modes field to communicate feature capability and use@ 2. the definitions of augmented start session and stop session commands (with corresponding acknowledgements)@ and 3. the definition of related procedures for TWAMP entities. The motivation for this feature is the ability to start and stop individual test sessions at will@ using a single TWAMP-Control connection. When the Server and Control-Client have agreed to use the Individual Session Control mode during control connection setup@ then the Control-Client@ the Server@ the Session-Sender@ and the Session- Reflector MUST all conform to the requirements of that mode@ as identified below. The original TWAMP-Control Start and Stop commands MUST NOT be used.