From what I understand from talking to ACT lighting, HES, and our companies network tech is that the MAnet and Artnet are two different protocols that are running down the same line. Just like a server at a business.

Now this is were I could be wrong... but I believe the Grandma is outputting the two different protocols with separate I.P. addresses. But, as I said, that is my feeble mind coming up with that hypothesis.