1 2004, Cisco Systems, Inc. All rights reserved. CCNA 4 v3.1 Module 3 PPP 222 2004, Cisco Systems, Inc. All rights reserved. Objectives 333 2004, Cisco Systems, Inc. All rights reserved. Introduction to Serial Communication Transmission system encodes bits into electrical voltage using methods like NRZ-L or AMI Some of the many serial communications standards include the following: RS-232-E V.35 High-Speed Serial Interface (HSSI) 444 2004, Cisco Systems, Inc. All rights reserved. Time-Division Multiplexing 555 2004, Cisco Systems, Inc. All rights reserved. Demarcation Point The point in the network where the responsibility of the service provider or "telco" ends. 666 2004, Cisco Systems, Inc. All rights reserved. DTE-DCE 777 2004, Cisco Systems, Inc. All rights reserved. Serial Connection Options 888 2004, Cisco Systems, Inc. All rights reserved. DTE/DCE Interface The DTE/DCE interface for a particular standard defines the following specifications: Mechanical/physical - Number of pins and connector type Electrical - Defines voltage levels for 0 and 1 Functional - Specifies the functions that are performed by assigning meanings to each of the signaling lines in the interface Procedural - Specifies the sequence of events for transmitting data 999 2004, Cisco Systems, Inc. All rights reserved. HDLC Encapsulation 10 2004, Cisco Systems, Inc. All rights reserved. Configuring HDLC Encapsulation 11 2004, Cisco Systems, Inc. All rights reserved. Troubleshooting a Serial Interface 12 2004, Cisco Systems, Inc. All rights reserved. Troubleshooting a Serial Interface Five possible problem states can be identified in the interface status line of the show interface serial display: Serial x is down, line protocol is down. Serial x is up, line protocol is down. Serial x is up, line protocol is up (looped). Serial x is up, line protocol is down (disabled). Serial x is administratively down, line protocol is down. 13 2004, Cisco Systems, Inc. All rights reserved. PPP Layered Architecture 14 2004, Cisco Systems, Inc. All rights reserved. PPP and the Data Link Layer 15 2004, Cisco Systems, Inc. All rights reserved. PPP and the Network Layer 16 2004, Cisco Systems, Inc. All rights reserved. Establishing a PPP Session 17 2004, Cisco Systems, Inc. All rights reserved. PPP Operation 18 2004, Cisco Systems, Inc. All rights reserved. Link Control Protocol Options 19 2004, Cisco Systems, Inc. All rights reserved. PPP Configuration Options 20 2004, Cisco Systems, Inc. All rights reserved. Network Control Protocol 21 2004, Cisco Systems, Inc. All rights reserved. PPP Authentication Protocols 22 2004, Cisco Systems, Inc. All rights reserved. PPP Authentication Protocols 23 2004, Cisco Systems, Inc. All rights reserved. Password Authentication Protocol (PAP) 24 2004, Cisco Systems, Inc. All rights reserved. Challenge Handshake Authentication Protocol (CHAP) CHAP provides protection against playback attack through the use of a variable challenge value that is unique and unpredictable. 25 2004, Cisco Systems, Inc. All rights reserved. PPP Encapsulation and Authentication Process 26 2004, Cisco Systems, Inc. All rights reserved. CHAP Authentication Process 27 2004, Cisco Systems, Inc. All rights reserved. Configuring PPP 28 2004, Cisco Systems, Inc. All rights reserved. Configuring PPP Authentication 29 2004, Cisco Systems, Inc. All rights reserved. PAP Configuration 30 2004, Cisco Systems, Inc. All rights reserved. CHAP Configuration 31 2004, Cisco Systems, Inc. All rights reserved. Verifying PPP 32 2004, Cisco Systems, Inc. All rights reserved. PPP Configuration Commands 33 2004, Cisco Systems, Inc. All rights reserved. Debug PPP Authentication 34 2004, Cisco Systems, Inc. All rights reserved. Summary