1. CCNA 5.0 Planning Guide
Chapter 3: Point-to-Point Connections

2. Chapter 3: Objectives In this chapter, you will be able to:
Explain the fundamentals of point-to-point serial communication across a WAN.
Configure HDLC encapsulation on a point-to-point serial link.
Describe the benefits of using PPP over HDLC in a WAN.
Describe the PPP layered architecture and the functions of LCP and NCP.
Explain how a PPP session is established.
Configure PPP encapsulation on a point-to-point serial link.
Configure PPP authentication protocols.
Use show and debug commands to troubleshoot PPP. 2

3. Chapter 3: Overview
This chapter covers the terms, technology, and protocols used in serial connections.
The HDLC and Point-to-Point Protocols (PPP) are introduced.
PPP is a protocol that is able to handle authentication, compression, error detection, monitor link quality, and logically bundles multiple serial connections together to share the load. 3

4. Chapter 3: Activities
What activities are associated with this chapter?
Class Activity – PPP Persuasion
Activity - Identify the Serial Communications Terminology
Syntax Checker – Troubleshooting a Serial Interface
Packet Tracer – Troubleshooting Serial Interfaces
Activity – Identify PPP Features and Operations
Activity – Identify the Steps in the LCP Link Negotiation Process
Syntax Checker – PPP Link Quality Monitoring Command
Syntax Checker – PAP and CHAP Authentication Configuration
Packet Tracer – Configuring PAP and CHAP Authentication
Lab – Configuring Basic PPP with Authentication 4

5. Chapter 3: Activities (cont.)
What activities are associated with this chapter?
Packet Tracer – Troubleshooting PPP with Authentication
Lab – Troubleshooting Basic PPP with Authentication
Class Activity – PPP Validation
Packet Tracer – Skills Integration Challenge 5

6. Chapter 3: Packet Tracer Activity Password
The password for all the Packet Tracer activities in this chapter is: PT_ccna5 6

7. Chapter 3: Assessment
Students should complete the Chapter 3 Exam after completing Chapter 3.
Worksheets, labs and quizzes can be used to informally assess student progress. 7

8. Chapter 3: New Terms
What terms and commands are introduced in this chapter?
Point-to-point Connection
Serial Communication
Parallel Communication
RS-232
V.35
HSSI
Multiplexing
Time-division Multiplexing
Multiplexer
Statistical Time-division Multiplexing
Synchronous Optical Network (SONET)
Synchronous Digital Hierarchy (SDH)
Local Loop
Customer Premises Equipment (CPE)
Demarcation Point
CSU/DSU
Network Terminating Unit (NTU) 8

9. Chapter 3: New Terms (cont.)
What terms and commands are introduced in this chapter?
DTE
DCE
Electronics Industry Association (EIA)
International Telecommunication Union Telecommunications Standardization Sector (ITU-T)
null modem
DB9
DB60
EIA/TIA-232
EIA/TIA-449
X.21
EIA/TIA-530
Smart serial cable
DS0, DS1, etc.
T1/T3
E1/E3
OC-X 9

10. Chapter 3: New Terms (cont.)
What terms and commands are introduced in this chapter?
HDLC
PPP
Serial Line Internet Protocol (SLIP)
X.25/Link Access Procedure Balanced (LAPB)
Frame Relay
PAP
CHAP
ATM
Circuit-switched
Packet-switched
Information Frames (I-frames)
Supervisory Frames (S-frames)
Unnumbered Frames (U-frames)
show controllers serial command
Link Control Protocol (LCP)
Network Control Protocols (NCPs)
IPv4, IPv6, Novell IPX, AppleTalk Control Protocol 10

11. Chapter 3: New Terms (cont.)
What terms and commands are introduced in this chapter?
Password Authentication Protocol (PAP)
Challenge Handshake Authentication Protocol (CHAP)
Frame Check Sequence (FCS)
Link Establishment And Configuration Negotiation
Link Quality Determination
Network Layer Protocol Configuration Negotiation
Configure-Request
Configure-Ack
Configure-Nak
Configure-Reject
Code-Reject
Protocol-Reject
Echo-Request
Echo-Reply
Discard-Request
Terminate-Request
Terminate-Ack
Code Identifier 11

12. Chapter 3: New Terms (cont.)
What terms and commands are introduced in this chapter?
Compression
Multilink
Stacker
Predictor
Error Detection
Magic Number
PPP Callback
encapsulation ppp command
compress predictor command
ppp quality percentage command
interface multilink 1 command
ppp multilink command
ppp multilink group 1 command
show ppp multilink command
ppp authentication pap command
Message Digest 5 (MD5)
ppp authentication chap command
username name password password command 12

13. Chapter 3: New Terms (cont.)
What terms and commands are introduced in this chapter?
debug ppp command
debug ppp packet command
debug ppp negotiation command
debug ppp error command
debug ppp authentication command 13

14. Chapter 3: Best Practices
Prior to teaching Chapter 3, the instructor should:
Complete Chapter 3 Assessment.
Ensure all activities are completed. This is a very important concept and hands-on time is vital.
Provide the students many PPP troubleshooting activities.
Encourage students to login with their cisco.com login and download 14

15. Chapter 3: Additional Help
For additional help with teaching strategies, including lesson plans, analogies for difficult concepts, and discussion topics, visit the CCNA Community at
If you have lesson plans or resources that you would like to share, upload them to the CCNA Community to help other instructors. 15

16. Chapter 3: Topics Not in ICND2 200-101
This section lists topics covered by this chapter that are NOT listed in the ICND Blueprint. Those topics are posted at
Instructors could skip these sections; however, they should provide additional information and fundamental concepts to assist the student with the topic.
ALL TOPICS IN CHAPTER 3 ARE OBJECTIVES OF THE ICND2. 16