We are trying to share a printer for use by iPad users. The printer is dire= ctly connected to a Mac running Printopia. Both the Mac and all of the iPad= s are connected to the same WLAN. It's working fine at one location, but no= t at all at another location (iPads cannot see the printer). The location i= t works at has standalone APs (mostly 1131AGs). The site it does not work a= t has lightweight APs (4402 WLC running 6.0.199.4, also with 1131AGs). The = controller has multicast enabled, has multicast mode set to 'multicast', an= d has a multicast address set to 239.21.0.1 (I've also tried 224.0.0.1). Th= e Mac and iPads all have normal connectivity. What might the problem be?