*** In this Article we will make a fast review about Point-to-Point Protocol and the steps of links establishment***
The Point-to-Point Protocol (PPP) is a data link protocol commonly used in establishing a direct connection between two networking nodes. It can provide connection authentication, transmission encryption , and compression.
PPP was designed to provide layer 2 connectivity over variety of serial links and other physical technologies, We might ask why is it important for us or service providers to use PPP protocol for remote dail-in users, it is all concerns about security and authentication.  For example, suppose you connect two machines in your computer lab together with a serial cable and want to run PPP between them. When one of these initiates a PPP link with the other, you don’t really need to worry about “who’s calling”. On the other hand, consider the Internet Service Providers using PPP for remote dial-in users. They generally want to allow only their customers to connect, not just anyone.
PPP allows us to use optional authentication protocol for links where authentication is important. During basic link setup by Link Control Protocol (LCP) devices can negotiate the use of an authentication protocol. If they agree, after the LCP link is set up a series of authentication messages are sent to verify the identity of the device initiating the link. Only if authentication is successful can the link configuration proceed.
The PPP suite initially defined two common different authentication protocols: the Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP). also Extensible Authentication Protocol (EAP) which is not frequently used.
After the link has been established, additional network (layer 3) configuration may take place. Most commonly, the Internet Protocol Control Protocol (IPCP) is used, although Internetwork Packet Exchange Control Protocol (IPXCP) and AppleTalk Control Protocol (ATCP) were once very popular. Internet Protocol Version 6 Control Protocol (IPv6CP) will see extended use in the future, when IPv6 replaces IPv4’s position as the dominant layer-3 protocol.
In the upcoming topic/article we will talk about the authentication protocols/methods of the PPP in brief, keep with us 🙂
Osama Aboelfath
Osama Aboelfath is co-founder at Recursive-lookup. Osama is a network engineer and developer with over 10 years of production network engineering, deployment & operation.
