优质博客：
[1]
http://hubpages.com/topics/technology/communications/voiceover-ip/5387
[2] voip开发包:
http://www.voip-sip-sdk.com/
云通信平台
http://cn.technode.com/post/2013-02-26/40049574594
星谷科技
http://info.secu.hc360.com/2011/07/150819535302.shtml
oatos
http://www.oatos.com/whatisoatos/