说明：  gprs协议栈代码.所谓协议栈就是对信息进行多次封装和解封的过程，以便能够在不同的实体间传送信息。本源代码来自Indian Institute of Technology
(gprs protocol stack code. The so-called agreement is the right information Stack several Packaging, and the course was cleared, to the various entities to disseminate information. Source code from the Indian Institute of Technology)