Applies To: Windows Server 2008, Windows Server 2008 R2
RRAS connections that run over a physical device (such as an ISDN adapter or analog modem) that is installed on both the calling and answering routers are known as dial-up connections. These connections differ from traditional WAN links in that they use existing telephone lines instead of dedicated lines. A dial-up connection differs from a VPN connection in that it does not cross the Internet.
In some areas, where DSL and cable modems are unavailable, using existing phone lines can reduce connection costs, especially where traffic volume between sites is low. Instead of paying for a permanent WAN connection 24 hours a day, you can configure the link to disconnect when no traffic crosses the connection for a specified period of time. For example, customers who use ISDN typically pay by the minute or by the byte, so configuring the call to hang up when the connection is idle reduces cost.
To keep data transmission secure, a dial-up connection uses private, dedicated lines or circuits across a carrier’s network. In addition, the connection uses Point-to-Point Protocol (PPP) user authentication and MPPE for data encryption.