Scenario: Ethernet: - AppleTV (fully updated) - Macbook Air (fully updated) Mountain Lion (via Thunderbolt Display) - Mac Pro iTunes server (fully updated) Regular Lion - All on the same network (192.168.1.*, same subnet 255.255.255.0) - Homesharing and AppleTV appear in iTunes library - Linksys E2000 Router These all play nice and homesharing and airplay mirroring work as expected. WiFi: - Macbook Air (fully updated) Mountain Lion. Same as above, but now unplugged from Ethernet - Still on same network (192.168.1.*, 255.255.255.0). Internet and file sharing stil work. Doesn't see the AppleTV for airplay mirroring, doesn't see the AppleTV in itunes. Internet and network still work. Thoughts on how/if this can be resolved?