I once designed and configured a satellite-microwave hybrid network for a large US customer with field offices around Borneo. I’ll never forget making the leased line handoffs back in Jakarta. I had exactly zero experience doing this so I googled around and read that BGP is what you would use to connect between our OSPF/UBNT net and their IGRP/Cisco corporate WAN. When asked to configure BGP on their routers, the guys from Tata were like “what do you think you are AT&T or something?” We did kind of feel that way until one season of lightning strikes took out most of our AirFibers.