Canreinvite question

Hi ,

I have a question about the canreinvite option in the sip extention configuration.

If i understand correctly the canreinvite option of an extention will enable
asterisk to connect 2 extentions directly instead of passing the audio via asterisk. ( and if needed it can reinvite those extentions in order to pass the audio channel through the pbx ), this seems like a good option in order to take the load off asterisk and also to avoid some bandwidth problems in case the extentions are “far” from the PBX.

my questions:

  1. What if i want an extention to be able to use this option for local ( inside network calls ) and for other calls not to be able to do that… ?

  2. Am i right about the canreinvite option ? how often is it used ?