When they were conceiving GOOSE as part of UCA2, they knew that they had to make it as good or better in performance and reliability than the existing wired practice and it needed to come at a lower cost too. While not a day one objective this is what they were aiming for. The requirements were derived from the protection practice of using a relay's contact output to drive the next device’s opto-isolator input. There were lots of naysayers, but the engineers kept thinking that if protection and control engineers drove the requirements, without sacrificing our principals, they would get it right. And they clearly did