38.331中信令后面的标签是什么意思？

xiangchina12

不理解这些便签是什么意思，虽然协议前面有说明，翻译过来还是不清楚协议想表达个什么意思，协议原文摘录如下
        

Abbreviation

      

Meaning

  
      

Cond conditionTag

   

Conditionally present

  

Presence of the field is specified in a tabular form following the ASN.1 segment.

     

CondC conditionTag

   

Configuration condition

  

Presence of the field is conditional to other configuration settings.

     

CondM conditionTag

   

Message condition

  

Presence of the field is conditional to other fields included in the  message.

     

Need S

   

Specified

  

Used for (configuration) fields, whose field description or procedure specifies the UE behavior performed  upon receiving a message with the field absent (and not if field description  or procedure specifies the UE behavior when field is not configured).

     

Need M

   

Maintain

  

Used for (configuration) fields that are stored by the UE i.e. not  one-shot. Upon receiving a message with the field absent, the UE maintains  the current value.

     

Need N

   

No action (one-shot  configuration that is not maintained)

  

Used for (configuration) fields that are not stored and whose presence  causes a one-time action by the UE. Upon receiving message with the field  absent, the UE takes no action.

     

Need R

   

Release

  

Used for (configuration) fields that are stored by the UE i.e. not  one-shot. Upon receiving a message with the field absent, the UE releases the  current value.