Informacast has been successfully tested with thousands of phones. The actual messages are broadcast via multicast while phone control is sent via unicast. The multicast message is made available on a stream on the network and must remain available until the last phone on the network has received the message. In an installation of thousands of phones the stream must remain available on the network until the last phone is activated via unicast phone control. This means that the first phones that are activated are forced to get the message for the entire time the stream is available, thus you get some phones that repeat the message.