Network Working Group D. Katz
Request for Comments: 1377 cisco
November 1992
The PPP OSI Network Layer Control Protocol (OSINLCP)
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 OSI
Network Layer Protocols.
This memo 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-ppp@ucdavis.edu mailing list.
Table of Contents
1. Introduction .......................................... 2
1.1 OSI Network Layer Protocols over PPP .................. 2
2. A PPP Network Control Protocol (NCP) for OSI .......... 5
2.1 Sending OSI NPDUs ..................................... 6
2.2 NPDU Alignment ........................................ 6
2.3 Network Layer Addressing Information .................. 6
3. OSINLCP Configuration Options ......................... 7
3.1 Align-NPDU ............................................ 7
REFERENCES ................................................... 9
ACKNOWLEDGEMENTS ............................................. 9
SECURITY CONSIDERATIONS ...................................... 10
CHAIR'S ADDRESS .............................................. 10
AUTHOR'S ADDRESS ............................................. 10
Katz [Page 1]
RFC 1377 PPP OSINLCP November 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).
1.1. OSI Network Layer Protocols over PPP
A number of protocols have been defined for the Network Layer of OSI,
including the Connectionless Network Layer Protocol (CLNP, ISO 8473)
[3], the End System to Intermediate System routing protocol (ES-IS,
ISO 9542) [4], the Intermediate System to Intermediate System routing
protocol (IS-IS, ISO 10589) [5], and the Inter-Domain Routeing
Protocol (IDRP, CD 10747) [6]. Generally, these protocols were
designed to run over non-reliable data link protocols such as PPP.
Network Layer Protocol Identifier (NLPID)
OSI Network Layer protocols can be discriminated according to the
first octet in each Network Protocol Data Unit (NPDU, that is,
packet), known as the Network Layer Protocol Identifier (NLPID),
which is defined in ISO/TR 9577 [7]. This allows the various
protocols to be run over a common data link without any
discriminator below the network layer.
Katz [Page 2]
RFC 1377 PPP OSINLCP November 1992
Inactive Network Layer Protocol
ISO/TR 9577 reserves a NLPID value of zero to represent the
"Inactive Network Layer Protocol", as defined in ISO 8473. The
datatracker.ietf.org