RFC 1172 (rfc1172) - Page 1 of 38
Point-to-Point Protocol (PPP) initial configuration options
Alternative Format: Original Text Document
Network Working Group D. Perkins
Request for Comments: 1172 CMU
R. Hobby
UC Davis
July 1990
The Point-to-Point Protocol (PPP) Initial Configuration Options
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet
community.
Please refer to the current edition of the "IAB Official Protocol
Standards" for the standardization state and status of this protocol.
This proposal is the product of the Point-to-Point Protocol Working
Group of the Internet Engineering Task Force (IETF). Comments on
this memo should be submitted to the IETF Point-to-Point Protocol
Working Group chair.
Distribution of this memo is unlimited.
Abstract
The Point-to-Point Protocol (PPP) provides a method for transmitting
datagrams over serial point-to-point links. PPP is composed of
1) a method for encapsulating datagrams over serial links,
2) an extensible Link Control Protocol (LCP), and
3) a family of Network Control Protocols (NCP) for establishing
and configuring different network-layer protocols.
The PPP encapsulating scheme, the basic LCP, and an NCP for
controlling and establishing the Internet Protocol (IP) (called the
IP Control Protocol, IPCP) are defined in The Point-to-Point Protocol
(PPP) [1].
This document defines the intial options used by the LCP and IPCP. It
also defines a method of Link Quality Monitoring and a simple
authentication scheme.
Perkins & Hobby [Page i]
RFC 1172 PPP Initial Options July 1990
Table of Contents
1. Introduction .......................................... 1
2. Link Control Protocol (LCP) Configuration Options ..... 1
2.1 Maximum-Receive-Unit ............................ 2
2.2 Async-Control-Character-Map ..................... 3
2.3 Authentication-Type ............................. 5
2.4 Magic-Number .................................... 7
2.5 Link-Quality-Monitoring ......................... 10
2.6 Protocol-Field-Compression ...................... 11
2.7 Address-and-Control-Field-Compression ........... 13
3. Link Quality Monitoring ............................... 15
3.1 Design Motivation ............................... 15
3.2 Design Overview ................................. 15
3.3 Processes ....................................... 16
3.4 Counters ........................................ 18
3.5 Measurements, Calculations, State Variables ..... 19
3.6 Link-Quality-Report Packet Format ............... 21
3.7 Policy Suggestions .............................. 25
3.8 Example ......................................... 25
4. Password Authentication Protocol ...................... 27
4.1 Packet Format ................................... 27
4.2 Authenticate .................................... 29
4.3 Authenticate-Ack ................................ 31
4.4 Authenticate-Nak ................................ 32
5. IP Control Protocol (IPCP) Configuration Options ...... 33
5.1 IP-Addresses .................................... 34
5.2 Compression-Type ................................ 36
REFERENCES ................................................... 37
SECURITY CONSIDERATIONS ...................................... 37
AUTHOR'S ADDRESS ............................................. 37
Perkins & Hobby [Page ii]
RFC 1172 PPP Initial Options July 1990
1. Introduction
The Point-to-Point Protocol (PPP) [1] proposes a standard method of
encapsulating IP datagrams, and other Network Layer protocol
information, over point-to-point links. PPP also proposes an
extensible Option Negotiation Protocol. [1] specifies only the
protocol itself; the initial set of Configuration Options are
described in this document. These Configuration Options allow MTUs
to be changed, IP addresses to be dynamically assigned, header
compression to be enabled, and much more.
This memo is divided into several sections. Section 2 describes
Configuration Options for the Link Control Protocol. Section 3
specifies the use of the Link Quality Monitoring option. Section 4
defines a simple Password Authentication Protocol. Finally, Section 5
specifies Configuration Options for the IP Control Protocol.
2. Link Control Protocol (LCP) Configuration Options
As described in [1], LCP Configuration Options allow modifications to
the standard characteristics of a point-to-point link to be
negotiated. Negotiable modifications proposed in this document
include such things as the maximum receive unit, async control
character mapping, the link authentication method, etc.
The initial proposed values for the LCP Configuration Option Type
field (see [1]) are assigned as follows:
1 Maximum-Receive-Unit
2 Async-Control-Character-Map
3 Authentication-Type
4 NOT ASSIGNED
5 Magic-Number
6 Link-Quality-Monitoring
7 Protocol-Field-Compression
8 Address-and-Control-Field-Compression
Perkins & Hobby
