CCNA 4 v3.1 Module 3
PPP
1
Objectives
2
Introduction to Serial Communication
Transmission system encodes bits into electrical
voltage using methods like NRZ-L or AMI
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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DTE/DCE Interface
• The DTE/DCE interface for a particular standard
defines the following specifications:
Mechanical/physical - Number of pins and connector
type
Electrical - Defines voltage levels for 0 and 1
Functional - Specifies the functions that are performed
by assigning meanings to each of the signaling lines in
the interface
Procedural - Specifies the sequence of events for
transmitting data
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HDLC Encapsulation
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Configuring HDLC Encapsulation
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Troubleshooting a Serial Interface
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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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Link Control Protocol Options
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PPP Configuration Options
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Network Control Protocol
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PPP Authentication Protocols
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PPP Authentication Protocols
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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
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Summary
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