RFC 1548 The Point-to-Point Protocol December 1993 Table of Contents 1. Introduction ................................................3 1.1 Specification of Requirements ...............................4 1.2 Terminology .................................................5 2. PPP Encapsulation ...........................................5 3. PPP Link Operation ..........................................8 3.1 Overview ....................................................8 3.2 Phase Diagram ...............................................8 3.3 Link Dead (physical-layer not ready) ........................9 3.4 Link Establishment Phase ....................................9 3.5 Authentication Phase ........................................9 3.6 Network-Layer Protocol Phase ................................10 3.7 Link Termination Phase ......................................10 4. The Option Negotiation Automaton ............................11 4.1 State Diagram ...............................................12 4.2 State Transition Table ......................................14 4.3 A Day in the Life ...........................................15 4.4 States ......................................................16 4.5 Events ......................................................19 4.6 Actions .....................................................23 4.7 Loop Avoidance ..............................................26 4.8 Counters and Timers .........................................26 5. LCP Packet Formats ..........................................27 5.1 Configure-Request ...........................................29 5.2 Configure-Ack ...............................................30 5.3 Configure-Nak ...............................................31 5.4 Configure-Reject ............................................33 5.5 Terminate-Request and Terminate-Ack .........................34 5.6 Code-Reject .................................................35 5.7 Protocol-Reject .............................................36 5.8 Echo-Request and Echo-Reply .................................37 5.9 Discard-Request .............................................39 6. LCP Configuration Options ...................................40 6.1 Maximum-Receive-Unit ........................................41 6.2 Async-Control-Character-Map .................................42 6.3 Authentication-Protocol .....................................43 6.4 Quality-Protocol ............................................45 6.5 Magic-Number ................................................46 6.6 Protocol-Field-Compression ..................................49 6.7 Address-and-Control-Field-Compression .......................50 APPENDIX A. LCP Recommended Options ..............................51 SECURITY CONSIDERATIONS ..........................................51 REFERENCES .......................................................52 ACKNOWLEDGEMENTS .................................................52 CHAIR'S ADDRESS ..................................................52 EDITOR'S ADDRESS .................................................53 Simpson