I see a lot of these hitting FS continuously - where would they be originating from? (The IP x.x.x.x is the local IP)

2017-01-19 12:06:07.773935 [NOTICE] switch_channel.c:1077 New Channel sofia/internal/123456@x.x.x.x [6ed9ba7d-4357-460d-a0b7-ff94bf871e7e]