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CCNA 4 v3.0 Module 3 PPP
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Objectives
• Serial point-to-point links
• PPP authentication
• Configuring PPP
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Introduction to Serial Communication
Some of the many serial communications standards include the following:
RS-232-E V.35 High-Speed Serial Interface (HSSI)
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Time-Division Multiplexing
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Demarcation Point
The point in the network where the responsibility of the service provider or "telco" ends.
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DTE-DCE
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Serial Connection Options
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HDLC Encapsulation
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Configuring HDLC Encapsulation
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Troubleshooting a Serial Interface
• Five possible problem states can be identified in the interface status line of the show interface serial display:
Serial x is down, line protocol is down.
Serial x is up, line protocol is down.
Serial x is up, line protocol is up (looped).
Serial x is up, line protocol is down (disabled).
Serial x is administratively down, line protocol is down.
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PPP Layered Architecture
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PPP and the Data Link Layer
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PPP and the Network Layer
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Establishing a PPP Session
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PPP Operation
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LCP Options
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PPP Configuration Options
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NCP
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PPP Authentication Protocols
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PPP Authentication
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Password Authentication Protocol (PAP)
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Challenge Handshake Authentication Protocol (CHAP)
CHAP provides protection against playback attack through the use of a variable challenge value that is unique and unpredictable.
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PPP Encapsulation and Authentication Process
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CHAP Authentication Process
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Configuring PPP
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Configuring PPP Authentication
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PAP Configuration
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CHAP Configuration
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Verifying PPP
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PPP Configuration Commands
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Debug PPP Authentication