EDIT: Checked Multicast/RTP: it appears the aforementioned plugin for Apple AirTunes forces the Multicast/RTP settings. Enabling Multicast/RTP independently of Apple AirTunes support yields same results. My apologies for the numerous comments.
EDIT: Checked Multicast/RTP: it appears the aforementioned plugin for Apple AirTunes forces the Multicast/RTP settings. Enabling Multicast/RTP independently of Apple AirTunes support yields same results. My apologies for the numerous comments.