有谁知道 LTE X2 的协议中，Presence的值M、 O是什么意思 ？

chestthinker

IE/Group Name	Presence	Range	IE type and reference	Semantics description
Procedure Code	O		INTEGER (0..255)	Procedure Code is to be used if Criticality Diagnostics is part of Error  Indication procedure, and not within the response message of the same procedure  that caused the error.
Triggering Message	O		ENUMERATED(initiating  message, successful outcome, unsuccessful outcome)	The Triggering  Message is used only if the Criticality Diagnostics is part of Error  Indication procedure.
Procedure  Criticality	O		ENUMERATED(reject,  ignore, notify)	This Procedure  Criticality is used for  reporting the Criticality of the Triggering message (Procedure).
Information  Element Criticality Diagnostics		0 ..  <maxNrOfErrors>
>IE Criticality	M		ENUMERATED(reject,  ignore, notify)	The IE  Criticality is used for  reporting the criticality of the triggering IE. The value "ignore'" shall not be used.
>IE ID	M		INTEGER (0..65535)	The IE ID of the not understood or missing IE
>Type Of Error	M		ENUMERATED(not  understood, missing, …)