2.1 Core Protocol (0)

The Energistics Core protocol (also referred to as Protocol 0) has the following responsibilities:

• Establishes the WebSocket connection.
• Manages session life cycle.

• Negotiates the subprotocols to be used in the session.

The Core protocol also defines common messages, which may be used in any protocol (such as the Exception message). These messages have a MessageTypeId >= 1000. When these messages are used, the protocol field in the message header will not necessarily be 0; it will be the appropriate value for the protocol that is using the common message (e.g., a ProtocolException on the Discovery protocol would use a value of 3).