说明：  PPT转pdf.想学IMS和SIP但是感觉资料太多,不知从何看起,也没有那么多时间.那就来看看这个ppt,花1个小时浏览一下,那你也是专家了.
(PPT to pdf. , Like IMS and SIP But feeling too much data, I do not know where to begin. is not so much time. then look at the ppt, spent an hour visit it, where you are also experts.)