2.2.3 Messages

The messages described in the following sections each contain the CommonHeader structure (section 2.2.2.2) that specifies the message type and length, and zero or more other structures as defined in section 2.2.2. In an implementation, the messages MUST contain all defined fields unless a field is marked as (optional). Optional fields MAY be included as required by the implementation.

When a message contains more than one structure, the location of the structures within the message MUST be in increasing numeric order as indicated by the value of the TypeId enumeration (section 2.2.1.3). Unless otherwise specified, a message MUST NOT contain multiple structures with the same TypeId (section 2.2.1.3) value.

Messages MAY contain structures that are not defined in this protocol. However, implementations of this protocol MUST ignore all message structures that are not specified in this specification [MS-TCC] to enable compatibility with future protocol versions.