|  |  | Summary

Now that you have completed this chapter, you should have a firm understanding of the following: PPP is the most widely used WAN protocol. PPP addresses the problems of Internet connectivity by providing a LCP and a family of NCPs to negotiate optional configuration parameters and facilities. A PPP session has four phases: Link establishment Link quality determination Network-layer protocol configuration Link termination. You can select PAP or CHAP when configuring PPP authentication. PAP is not a strong authentication protocol. CHAP provides protection against playback attacks through the use of a variable challenge value that is unique and unpredictable. You configure the interface for PPP encapsulation by using the encapsulation ppp command. When PPP is configured, you can check its LCP and NCP states by using the show interfaces command.
| Threaded Case Study
Washington School District Project Task: PPP

In this chapter, you learned concepts and configuration processes that will help you configure PPP in the Washington School District network. As part of the configuration, you need to complete the following tasks:

1. Apply PPP to the existing WAN designs and describe the effects.
2. Document the router commands necessary to implement PPP on the router interfaces and how the router configuration changes.
3. Describe the benefits of PPP as a layer 2 WAN protocol versus other options.
4. Apply the CCNA Certification Exam Learning Objectives to your specific design. This will require a paragraph on how the learning objectives relate to your design. Learning objectives can be grouped together for the purpose of explanation. In this way, you will be studying for your CCNA Certification Exam as you work through the case study.

CCNA Certification Exam Learning Objectives
(*** are explicit CCNA Exam objectives; unmarked are knowledge assumed by the exam):

OSI Model

- Describe the OSI model layer(s) at which the Point to Point Protocol (PPP) operates and its function at those layers.

Point to Point Protocol

- Describe what major types of WAN links are supported by PPP.
- Describe what the function of the Network Control Protocol (NCP ) is within PPP.
- Describe what the function of the Link Control Protocol (LCP) is within PPP.
- Describe the functions of PAP and CHAP in a PPP implementation.
- Identify PPP operations to encapsulate WAN data on Cisco Routers***

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