18-03-2011, 06:31 PM
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| M.Arsalan Qureshi | | Join Date: Oct 2008 Location: Garden Town, Multan Cantt
Posts: 616
Program / Discipline: BSTS Class Roll Number: 09-31 | |
Multiple Access Multiple Access * The Point-to-Point Protocol (PPP) was designed to provide a dedicated line for users who need Internet access via a telephone line or a cable TV connection. * A PPP connection goes through these phases: idle, establishing, authenticating (optional), networking, and terminating. * At the data link layer, PPP employs a version of HDLC. * The Link Control Protocol (LCP) is responsible for establishing, maintaining, configuring, and terminating links. * Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP) are two protocols used for authentication in PPP. * PAP is a two-step process. The user sends authentication identification and a password. The system determines the validity of the information sent. * CHAP is a three-step process. The system sends a value to the user. The user manipulates the value and sends its result. The system verifies the result. * Network Control Protocol (NCP) is a set of protocols to allow the encapsulation of data coming from network layer protocols; each set is specific for a network layer protocol that requires the services of PPP. * Internetwork Protocol Control Protocol (IPCP), an NCP protocol, establishes and terminates a network layer connection for IP packets.
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