I didn’t say “OSI protocol”. In fact is there even such thing as an “OSI protocol”? There are OSI layers. Those layers will have protocols and other such standards attached. Of which MAC addresses are a standard which sits inside a sub-layer of the datalink layer. And UPnP is a protocol that utilises HTTP, which itself resides in the application layer of OSI. But I don’t recall ever hearing the term “OSI protocol” before. However I’m also not a networking specialist.