Network Working Group G. McGregor
Request for Comments: 1332 Merit
Obsoletes: RFC 1172 May 1992
The PPP Internet Protocol Control Protocol (IPCP)
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet
community, and requests discussion and suggestions for improvements.
Please refer to the current edition of the "IAB Official Protocol
Standards" for the standardization state and status of this protocol.
Distribution of this memo is unlimited.
Abstract
The Point-to-Point Protocol (PPP) [1] provides a standard method of
encapsulating Network Layer protocol information over point-to-point
links. PPP also defines an extensible Link Control Protocol, and
proposes a family of Network Control Protocols (NCPs) for
establishing and configuring different network-layer protocols.
This document defines the NCP for establishing and configuring the
Internet Protocol [2] over PPP, and a method to negotiate and use Van
Jacobson TCP/IP header compression [3] with PPP.
This RFC is a product of the Point-to-Point Protocol Working Group of
the Internet Engineering Task Force (IETF).
McGregor [Page i]
RFC 1332 PPP IPCP May 1992
Table of Contents
1. Introduction .......................................... 1
2. A PPP Network Control Protocol (NCP) for IP ........... 2
2.1 Sending IP Datagrams ............................ 2
3. IPCP Configuration Options ............................ 4
3.1 IP-Addresses .................................... 5
3.2 IP-Compression-Protocol ......................... 6
3.3 IP-Address ...................................... 8
4. Van Jacobson TCP/IP header compression ................ 9
4.1 Configuration Option Format ..................... 9
APPENDICES ................................................... 11
A. IPCP Recommended Options .............................. 11
SECURITY CONSIDERATIONS ...................................... 11
REFERENCES ................................................... 11
ACKNOWLEDGEMENTS ............................................. 11
CHAIR'S ADDRESS .............................................. 12
AUTHOR'S ADDRESS ............................................. 12
McGregor [Page ii]
RFC 1332 PPP IPCP May 1992
1. Introduction
PPP has three main components:
1. A method for encapsulating datagrams over serial links.
2. A Link Control Protocol (LCP) for establishing, configuring,
and testing the data-link connection.
3. A family of Network Control Protocols (NCPs) for establishing
and configuring different network-layer protocols.
In order to establish communications over a point-to-point link, each
end of the PPP link must first send LCP packets to configure and test
the data link. After the link has been established and optional
facilities have been negotiated as needed by the LCP, PPP must send
NCP packets to choose and configure one or more network-layer
protocols. Once each of the chosen network-layer protocols has been
configured, datagrams from each network-layer protocol can be sent
over the link.
The link will remain configured for communications until explicit LCP
or NCP packets close the link down, or until some external event
occurs (an inactivity timer expires or network administrator
intervention).
McGregor [Page 1]RFC 1332 PPP IPCP May 19922. A PPP Network Control Protocol (NCP) for IP
The IP Control Protocol (IPCP) is responsible for configuring,
enabling, and disabling the IP protocol modules on both ends of the
point-to-point link. IPCP uses the same packet exchange machanism as
the Link Control Protocol (LCP). IPCP packets may not be exchanged
until PPP has reached the Network-Layer Protocol phase. IPCP packets
received before this phase is reached should be silently discarded.
The IP Control Protocol is exactly the same as the Link Control
Protocol [1] with the following exceptions:
Data Link Layer Protocol Field
Exactly one IPCP packet is encapsulated in the Information field
of PPP Data Link Layer frames where the Protocol field indicates
datatracker.ietf.org