Early study of tunneling techniques by the author and his colleagues had shown that the application of tunneling technique should have much broad potentials than those defined by the previous protocols ( e . g . l2f and pptp for version 1 and l2tp for version 2 ) , which is exactly the reason stimulated this research work 本论文作者及研究小组的其他同学对早期的第二层隧道协议的分析研究表明：隧道中继的思想可以比第一版( l2f 、 l2tp )和第二版( l2tpv2 )定义的范围有更广泛的应用前景。
This dissertation presented a theoretical work as well as an experimental implementation of the l2tp carried out at the sichuan network communication key laboratory . this project was spurred by idea of extending the application of the tunneling technique to a broad area as a result of a preliminary study on tunneling techniques , especially on l2f , pptp and l2tp ( commonly referred to as l2tpv2 ) 本论文所反映的工作，是四川省网络通信技术重点实验室“二层隧道协议课题组”的共同成果，该项目起因是试图对早期版本的隧道传输技术( l2f 、 pptp和l2tp )的非对称应用模式推广到对称应用模式，以及将该思想应用于其他层协议的隧道传输。
This is achieved by allowing the user to tunnel through the internet or another public network using a protocol such as microsoft point - to - point tunneling protocol pptp available with the microsoft windows nt version 4 . 0 or microsoft windows 2000 operating system , or layer two tunneling protocol l2tp available with the windows 2000 operating system 其实现方法是允许用户使用如microsoft windows nt 4 . 0或microsoft windows 2000操作系统中的microsoft点对点隧道协议( pptp )或者windows 2000操作系统中的第二层隧道协议( l2tp ) ，将internet或另一公用网络作为通道。
