TCP/IP and Dial-up Support
Windows Mobile implements dial-up networking with Remote Access Service (RAS) and Point-to-Point Protocol (PPP).
Dial-up networking allows a Windows Mobile device to access network resources from a remote location.
RAS connects a client to a host computer, known as a remote access server. A Windows Mobile device running RAS connects to a remote access server using PPP.
PPP is a member of the TCP/IP protocol suite. It specifies an industry-standard suite of control protocols that were designed to facilitate communication between two computers through a serial, network, or infrared interface in a dynamically changing network. A Windows Mobile device running Remote Access Service (RAS) uses PPP to package data packets from multiple protocols and forward them to a server over point-to-point links. PPP is an improvement over Serial Line Internet Protocol (SLIP) in its error detection capability and its ability to handle both synchronous and asynchronous communication.