Ccna routing and Switching Complete Study Guide

PPP Session Establishment

When PPP connections are started, the links go through three phases of session 

establishment, as shown in Figure 21.13:

f i g u r e   21.13     PPP session establishment

PPP Session Establishment

1. Link establishment phase

2. Authentication phase (optional)

3. Network layer protocol phase

PPP

Link-establishment phase    LCP packets are sent by each PPP device to configure and test 

the link. These packets contain a field called Configuration Option that allows each device 

to see the size of the data, the compression, and authentication. If no Configuration Option 

field is present, then the default configurations will be used.