FreeSWITCH pins the media by default without the need to use proxy media, proxy media was created to move formats thru FreeSWITCH that it doesn't know about, like G729, various pass thru video codecs and t.38 before we had full support.

So I recommend you not use proxy media as it may go away in the future.

Anything you've read that states performance improvements using proxy media are all false, the performance characteristics can't really be gauged on most modern systems. 

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b