Point to Point

Written by: Les Harper - Jan 9, 2009

PPP (Point-to-Point Protocol):

PPP, Point-to-Point Protocol, is the standard remote access protocol in use today. PPP is actually a family of protocols that work together to provide connection services. PPP is commonly used to act as a data link layer (layer two of the OSI model) protocol for connection over synchronous and asynchronous circuits, where it has largely superseded the older, non-standard Serial Line Internet Protocol (SLIP) Because PPP is an industry standard, it offers interoperability between different software vendors in various remote access implementations. PPP provides a number of security enhancements compared to regular SLIP. PPP allows remote clients and servers to negotiate data encryption methods and authentication methods and support new technologies. PPP even gives administrators the ability to choose which particular local area network (LAN) protocol to use over a remote link. For example, administrators can choose among NetBIOS Extended User Interface (NetBEUI), AppleTalk, or TCP/IP. PPP is capable of operating across any DTE (Data Terminal Equipment and refers to an end instrument that converts user information into signals for transmission)/DCE (Data Communications Equipment) interface. PPP does not impose any restriction regarding transmission rate other than those imposed by the particular DTE/DCE interface in use. PPP allows a user with a personal computer, such a Macintosh or a PC, and a modem to connect to the Internet, without having to first log on to a remote machine. This capability enables the user to make use of Internet applications and tools such as telnet, file transfer (ftp), electronic mail, and graphical web browsers directly on his or her personal computer. A computer with a PPP connection is able to simulate a direct connection to the Internet. To accomplish this, the user needs: ? A computer and modem ? A PPP account with his or her Internet Service Provider ? PPP software and TCP/IP software installed on the user's computer. ? An IP address - this may be permanently assigned to the user's computer by the provider or assigned dynamically at the time of the connection. A user's modem dials up a remote computer at an Internet Service Provider (ISP). The PPP software requests a PPP connection. Once the connection is made, the service provider assigns the user's computer an IP address (in the case of a service provider who assigns IP addresses dynamically). The TCP/IP software on the user's computer "takes over" and manages the flow of data between the Internet and the user's computer. During the establishment of a PPP connection between the remote system and the server, the remote server needs to authenticate the remote user and does so by using the PPP authentication protocols. PPP accommodates a number of authentication protocols, and it's possible on many systems to configure more than one authentication protocol. The protocol used in the authentication process depends on the security configurations established between the remote user and the server. A PPP connection allows a user to take full advantage of the Internet, because it enables the user's computer to simulate a direct connection to the Internet; because it makes it possible to use Internet applications and tools directly on the user's computer; because it allows the user access to the graphics, sound, multimedia etc. available on the Internet.