Developing network software in embedded systems, such as digital set-top boxes, requires coding under limited computing resources. This paper presents the porting of Point-to-point Protocol (PPP) software, PPPD, to an embedded system. The PPP is the most popular link layer protocol for the information appliance, to an embedded system. In order to achieve this, problems to be solved for the porting were identified and methods to solve the problems were described. First, PPP source codes were divided into modules. Next, functions of each module were analyzed and interfaces between the modules were delineated. With the analysis results, porting to the embedded system was described. The normal operation of the ported software was verified with the help of a network packet analyzer. Finally, experiences during the porting were presented. The method developed in th paper can be applied to the porting of software to an embedded system as well as the porting of network software.