3.1.5.2.4 Context Cancellation Binding

The contents of a received message that conforms to the syntax specified in section 2.2.2.1.4 MAY<7> be ignored by the client. Otherwise, the client MUST process a received message conforming to the syntax specified in section 2.2.2.1.4.

Exactly one message MUST be processed as part of the context cancellation binding. Additional messages MUST be rejected.