Post on 07-Apr-2018
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 1/27
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE I Chapter 6 1
Point-to-Point Protocol
(PPP)
Accessing the WAN–
Chapter 2
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 2/27
© 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.
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 3/27
© 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
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 4/27
© 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.
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 5/27
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 5
Fundamental Concepts of Point-to-PointSerial Communication
Demarcation point
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 6/27
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 6
Fundamental Concepts of Point-to-PointSerial Communication
DTE and DCE
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 7/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 7
Fundamental Concepts of Point-to-PointSerial Communication
WAN Protocols
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 8/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 8
Fundamental Concepts of Point-to-PointSerial Communication
Configure HDLC encapsulation on a router
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 9/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 9
Fundamental Concepts of Point-to-PointSerial Communication Troubleshooting a serial connection
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 10/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 10
Fundamental Concepts of Point-to-PointSerial Communication Troubleshooting a serial connection
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 11/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 11
Fundamental Concepts of Point-to-PointSerial Communication Troubleshooting a serial connection
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 12/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 12
Point-to-Point Concepts
PPP in terms of its use in WAN links
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 13/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 13
Point-to-Point Concepts
General function of each layer of PPP architecture
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 14/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 14
Point-to-Point Concepts
Purpose and format of each of the fields in a PPPframe
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 15/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 15
Point-to-Point Concepts
Three phases of PPP session establishment
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 16/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 16
Point-to-Point Concepts
Role of the LCP in PPP
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 17/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 17
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].
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 18/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 18
Configure PPP on a Serial Interface
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 19/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 19
Configure PPP on a Serial Interface
Output of the show interfaces serial command
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 20/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 20
Configure PPP on a Serial Interface
Output of the debug ppp command
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 21/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 21
Configuring PPP with Authentication
Differentiate between PAP and CHAP
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 22/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 22
Configuring PPP with Authentication
How to use PAP to authenticate a PPP connection
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 23/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 23
Configuring PPP with Authentication
How to use CHAP to authenticate a PPP connection
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 24/27 © 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 24
Configuring PPP with Authentication
Outline the PPP encapsulation and authenticationprocess on a flow chart
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 25/27
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 25
Configuring PPP with Authentication
How to configure a PPP connection with authentication
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 26/27
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicITE 1 Chapter 6 26
Configuring PPP with Authentication
Output of the debug ppp authentication command
8/6/2019 Exploration Accessing WAN Chapter2a
http://slidepdf.com/reader/full/exploration-accessing-wan-chapter2a 27/27