Exploration Accessing WAN Chapter2a

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 © 2006 Cisco Syst ems, I nc . All right s res er ve d. Ci sco Publ ic ITE I Chapter 6 1 Point-to-Point Protocol (PPP) Accessing the WAN Chapter 2

Transcript of Exploration Accessing WAN Chapter2a

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 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE I Chapter 6 1

Point-to-Point Protocol

(PPP)

Accessing the WAN–

Chapter 2

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 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 2

Objectives

Describe the fundamental concepts of point-to-point serialcommunication including TDM, demarcation point, DTE-DCEfunctions, HDLC encapsulation, and serial interfacetroubleshooting.

Describe PPP concepts including PPP layered architecture, PPPframe structure, PPP session establishment, multiprotocol

encapsulation support, link control protocol (LCP), networkcontrol protocol (NCP), and Internet Protocol Control Protocol(IPCP).

Configure PPP on a serial interface including enabling PPPencapsulation, verifying the PPP connection and troubleshooting

encapsulation problems. Configure PPP authentication including explaining PAP and

CHAP authentication protocols, configuring PPP authenticationusing PAP and CHAP, and troubleshooting PPP authenticationproblems.

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 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 3

Fundamental Concepts of Point-to-PointSerial Communication Concept of serial communication as the basis of WAN

technologies

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 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 4

Fundamental Concepts of Point-to-PointSerial Communication

TDM and STDM

STDM uses a variable time slot length allowingchannels to compete for any free slot space.

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Fundamental Concepts of Point-to-PointSerial Communication

Demarcation point

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Fundamental Concepts of Point-to-PointSerial Communication

DTE and DCE

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Fundamental Concepts of Point-to-PointSerial Communication

WAN Protocols

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Fundamental Concepts of Point-to-PointSerial Communication

Configure HDLC encapsulation on a router

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Fundamental Concepts of Point-to-PointSerial Communication Troubleshooting a serial connection

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Fundamental Concepts of Point-to-PointSerial Communication Troubleshooting a serial connection

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Fundamental Concepts of Point-to-PointSerial Communication Troubleshooting a serial connection

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Point-to-Point Concepts

PPP in terms of its use in WAN links

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Point-to-Point Concepts

General function of each layer of PPP architecture

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Point-to-Point Concepts

Purpose and format of each of the fields in a PPPframe

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Point-to-Point Concepts

Three phases of PPP session establishment

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Point-to-Point Concepts

Role of the LCP in PPP

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Point-to-Point Configuration Options

LCP Options

Authentication - Peer routers exchange authentication messages. Two authentication choices arePassword Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol(CHAP). Authentication is explained in the next section.Compression - Increases the effective throughput on PPP connections by reducing the amount ofdata in the frame that must travel across the link. The protocol decompresses the frame at itsdestination. Two compression protocols available in Cisco routers are Stacker and Predictor.

Error detection - Identifies fault conditions. The Quality and Magic Number options help ensure areliable, loop-free data link. The Magic Number field helps in detecting links that are in a looped-back condition. Until the Magic-Number Configuration Option has been successfully negotiated, theMagic-Number must be transmitted as zero. Magic numbers are generated randomly at each endof the connection.

Multilink - Cisco IOS Release 11.1 and later supports multilink PPP. This alternative provides load

balancing over the router interfaces that PPP uses. Multilink PPP (also referred to as MP, MPPP,MLP, or Multilink) provides a method for spreading traffic across multiple physical WAN links whileproviding packet fragmentation and reassembly, proper sequencing, multivendor interoperability,and load balancing on inbound and outbound traffic. Multilink is not covered in this course.

PPP Callback - To enhance security, Cisco IOS Release 11.1 and later offers callback over PPP.With this LCP option, a Cisco router can act as a callback client or a callback server. The clientmakes the initial call, requests that the server call it back, and terminates its initial call. The callback

router answers the initial call and makes the return call to the client based on its configurationstatements. The command is ppp callback [accept | request].

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Configure PPP on a Serial Interface

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Configure PPP on a Serial Interface

Output of the show interfaces serial command

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Configure PPP on a Serial Interface

Output of the debug ppp command

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Configuring PPP with Authentication

Differentiate between PAP and CHAP

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Configuring PPP with Authentication

How to use PAP to authenticate a PPP connection

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Configuring PPP with Authentication

How to use CHAP to authenticate a PPP connection

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Configuring PPP with Authentication

Outline the PPP encapsulation and authenticationprocess on a flow chart

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Configuring PPP with Authentication

How to configure a PPP connection with authentication

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Configuring PPP with Authentication

Output of the debug ppp authentication command

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