You can initiate TCP socket connections from AIR (No UDP or
server sockets though). I don't think there are any existing
actionscript APIs for SIP, though you could write your own. You may
want to check out
It's not possible to integrate LIB or OCX stuff into AIR. AIR
supports decompression using the ZLIB and DEFLATE algorithms (check
out flash.utils.ByteArray). No support for CAB files though.