Services in a Converged
WAN
Accessing the WAN – Chapter 1
ITE I Chapter 6
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Objectives
 Describe how the Cisco Enterprise Composite
Model (ECNM) provides integrated services
over an Enterprise network.
 Describe the key WAN technology concepts.
 Identify the appropriate WAN technologies to
use when matching ECNM best practices with
typical enterprise requirements for WAN
communications.
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Describe How ECNM Provides Integrated
Services over an Enterprise Network
 Explain the purpose and function of WANs
ITE 1 Chapter 6
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Describe How ECNM Provides Integrated
Services over an Enterprise Network
 Business growth
ITE 1 Chapter 6
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Describe How ECNM Provides Integrated
Services over an Enterprise Network
 Cisco Enterprise Network Architecture Modules
ITE 1 Chapter 6
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Describe How ECNM Provides Integrated
Services over an Enterprise Network
 Explain the purpose of Cisco Enterprise Architectures
ITE 1 Chapter 6
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Describe the Key WAN Technology
Concepts
 Describe WAN functions in terms of the OSI Reference
Model
ITE 1 Chapter 6
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Describe the Key WAN Technology
Concepts
ITE 1 Chapter 6
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WAN Data-Link-Layer protocols
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Describe the Key WAN Technology
Concepts
 Describe the switching technologies used for WANs in
an Enterprise setting
ITE 1 Chapter 6
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Connecting subscribers to WAN link
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Select the Appropriate WAN Technology to meet
ECNM Requirements
 Describe how Enterprises use leased line services to
provide a WAN connection
ITE 1 Chapter 6
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Circuit Switching options
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Packet switching options
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Factors to consider in WAN
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Summary
 A WAN is defined as
A data communications network that operates beyond the
geographic scope of a LAN
 WAN primarily operate on layer 1 & 2 of the OSI model
 WAN technologies include
–Leased line
–ISDN
–Frame relay
–X.25
–ATM
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Summary
 Cisco Enterprise Architecture
–This is an expansion of the hierarchical model that further
divides the enterprise network into
•Physical areas
•Logical areas
•Functional areas
 Selecting the appropriate WAN technology requires
considering some of the following:
–WAN’s purpose
–Geographic scope of WAN
–Traffic requirements
–If WAN uses a public or private infrastructure
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ITE 1 Chapter 6
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Point-to-Point Protocol
(PPP)
Accessing the WAN – Chapter 2
ITE I Chapter 6
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Objectives

Describe the fundamental concepts of point-to-point serial
communication including TDM, demarcation point, DTE-DCE
functions, HDLC encapsulation, and serial interface
troubleshooting.

Describe PPP concepts including PPP layered architecture, PPP
frame structure, PPP session establishment, multiprotocol
encapsulation support, link control protocol (LCP), network
control protocol (NCP), and Internet Protocol Control Protocol
(IPCP).

Configure PPP on a serial interface including enabling PPP
encapsulation, verifying the PPP connection and troubleshooting
encapsulation problems.

Configure PPP authentication including explaining PAP and
CHAP authentication protocols, configuring PPP authentication
using PAP and CHAP, and troubleshooting PPP authentication
problems.
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Describe the Fundamental Concepts of
Point-to-Point Serial Communication
 Describe the concept of serial communication as the
basis of WAN technologies
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Describe the Fundamental Concepts of
Point-to-Point Serial Communication
 Explain how two or more data streams are transported
across a single physical connection using TDM
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Describe the Fundamental Concepts of
Point-to-Point Serial Communication
 Define the location of the demarcation point relative to
customer and service provider networks
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Describe the Fundamental Concepts of
Point-to-Point Serial Communication
 Explain the terms DTE and DCE with relative to the
location of devices in a network
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Describe the Fundamental Concepts of
Point-to-Point Serial Communication
 Describe how high-level data link control (HDLC) uses
one of three frame types to encapsulate data
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Describe the Fundamental Concepts of
Point-to-Point Serial Communication
 Explain when and how to configure HDLC
encapsulation on a router
ITE 1 Chapter 6
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Describe Point-to-Point Concepts
 Describe PPP in terms of its use in WAN links
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Describe Point-to-Point Concepts
 Describe the general function of each layer of PPP
architecture
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Describe Point-to-Point Concepts
 Define the three phases of PPP session establishment
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Describe Point-to-Point Concepts
 Explain the role of the LCP in PPP
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Describe Point-to-Point Concepts
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Configuring PPP with Authentication
 Differentiate between PAP and CHAP
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Configuring PPP with Authentication
 Describe how to use PAP to authenticate a PPP
connection
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Configuring PPP with Authentication
 Describe how to use CHAP to authenticate a PPP
connection
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Configuring PPP with Authentication
 Outline the PPP encapsulation and authentication
process on a flow chart
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Configuring PPP
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Configuring PPP with Authentication
 Explain how to configure a PPP connection with
authentication
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Configuring PPP with PAP Authentication
Left(config)# interface Serial 0/0
Left(config-if)# ip address 192.168.1.1 255.255.255.252
Left(config-if)# encapsulation ppp
Left(config-if)# ppp authentication pap
Right(config)# interface Serial 0/0
Right(config-if)# ip address 192.168.1.2 255.255.255.252
Right(config-if)# encapsulation ppp
Right(config-if)# ppp authentication pap
Configuration of Serial interface, addressing scheme
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Configuring PPP with PAP Authentication
Left(config)# interface Serial 0/0
Left(config-if)# ip address 192.168.1.1 255.255.255.252
Left(config-if)# encapsulation ppp
Left(config-if)# ppp authentication pap
Right(config)# interface Serial 0/0
Right(config-if)# ip address 192.168.1.2 255.255.255.252
Right(config-if)# encapsulation ppp
Right(config-if)# ppp authentication pap
Activation of PPP encapsulation, specify authentication type
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Configuring PPP with PAP Authentication
Left(config-if)# encapsulation ppp
Left(config-if)# ppp authentication pap
Left(config-if)# ppp pap sent-username Left password LE
Right(config-if)# encapsulation ppp
Right(config-if)# ppp authentication pap
Right(config-if)# ppp pap sent-username Right password RI
Set credentials that are sent during authentication
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Configuring PPP with PAP Authentication
Left(config-if)# encapsulation ppp
Left(config-if)# ppp authentication pap
Left(config-if)# ppp pap sent-username Left password LE
Left(config)# username Right password RI
Right(config-if)# encapsulation ppp
Right(config-if)# ppp authentication pap
Right(config-if)# ppp pap sent-username Right password RI
Right(config)# username Left password LE
Set credentials, that are verified during authentication
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Configuring PPP with CHAP Authentication
Left(config-if)# encapsulation ppp
Left(config-if)# ppp authentication chap
Left(config-if)# ppp chap hostname Left
Left(config-if)# ppp chap password LE
Left(config)# username Right password RI
What is the difference when
Configuring the same witch CHAP?
Right(config-if)# encapsulation ppp
Right(config-if)# ppp authentication chap
Right(config-if)# ppp chap hostname Right
Right(config-if)# ppp chap password RI
Right(config)# username Left password LE
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Configure PPP on a Serial Interface
 Explain the output of the show interfaces serial
command
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Configure PPP on a Serial Interface
 Explain the output of the debug ppp command
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Debugging PPP
 Explain the output of the debug ppp authentication
command
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Summary
 PPP is a widely used WAN protocol
 PPP provides multi-protocol LAN to WAN connections
 PPP session establishment – 4 phases
Link establishment
Link quality determination
Network layer protocol configuration negotiation
Link termination
 WAN Encapsulation
–HDLC default encapsulation
–PPP
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Summary
 PPP authentication
–PAP
•2 way handshake
–CHAP
•3 way handshake
–Use debug ppp authentication to confirm authentication
configuration
 PPP configuration
–Done on a serial interface
 After PPP configuration, use show interfaces command
to display:
–LCP state
–NCP state
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ITE 1 Chapter 6
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