Network Working Group D. Perkins
Request for Comments: 1134 CMU
November 1989
The Point-to-Point Protocol: A Proposal for Multi-Protocol
Transmission of Datagrams Over Point-to-Point Links
Table of Contents
Status of this Memo ................................... 2
Abstract .............................................. 2
1. Introduction ....................................... 2
1.1 Motivation ........................................ 2
1.2 Overview of PPP ................................... 3
1.3 Organization of the document ...................... 4
2. Physical Layer Requirements ........................ 4
3. The Data Link Layer ................................ 4
3.1 Frame Format ...................................... 5
4. The PPP Link Control Protocol (LCP) ................ 8
4.1 The LCP Automaton ................................. 9
4.1.1 Overview ........................................ 9
4.1.2 State Diagram ................................... 10
4.1.3 State Transition Table .......................... 12
4.1.4 Events .......................................... 12
4.1.5 Actions ......................................... 14
4.1.6 States .......................................... 16
4.2 Loop Avoidance .................................... 19
4.3 Packet Format ..................................... 19
4.3.1 Configure-Request ............................... 21
4.3.2 Configure-Ack ................................... 21
4.3.3 Configure-Nak ................................... 22
4.3.4 Configure-Reject ................................ 24
4.3.5 Terminate-Request and Terminate-Ack ............. 25
4.3.6 Code-Reject ..................................... 26
4.3.7 Protocol-Reject ................................. 27
4.3.8 Echo-Request and Echo-Reply ..................... 28
4.3.9 Discard-Request ................................. 29
4.4 Configuration Options ............................. 30
4.4.1 Format .......................................... 31
5. A PPP Network Control Protocol (NCP) for IP ........ 32
5.1 Sending IP Datagrams .............................. 33
APPENDICES ............................................ 33
A. Asynchronous HDLC .................................. 33
B. Fast Frame Check Sequence (FCS) Implementation ..... 35
B.1 FCS Computation Method ............................ 35
B.2 Fast FCS table generator .......................... 36
Perkins