Network Working Group M. Allen
Internet Draft Novell, Inc.
June, 1992
IPX PPP Internetwork Packet Exchange Control Protocol [IPXCP]
Status of this Memo
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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-
ppp@ucdavis.edu mailing list. The expiration date is 12/15/92.
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 IPX protocol over PPP and MUST be used in
conjunction with the Informational RFC "Novell IPX Over
Various WAN Media", June 1992, Michael Allen.
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1. Introduction
PPP has three main components:
a. A method for encapsulating datagrams over serial links.
b. A Link Control Protocol (LCP) for establishing,
configuring, and testing the data-link connection.
c. A family of Network Control Protocols (NCPs) for
establishing and configuring different network-layer
protocols. PPP is designed to allow the simultaneous
use of multiple 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).
2. IPX PPP Network Control Protocol (NCP)
The IPX Control Protocol (IPXCP) is responsible for
configuring, enabling, and disabling the IPX protocol
modules on both ends of the point-to-point link. IPXCP uses
the same packet exchange mechanism as the Link Control
Protocol (LCP). IPXCP packets may not be exchanged until
PPP has reached the Network-Layer Protocol phase. IPXCP
packets received before this phase is reached should be
silently discarded.
The IPX Control Protocol is exactly the same as the Link
Control Protocol [1] with the following exceptions:
Data Link Layer Protocol Field
Exactly one IPXCP packet is encapsulated in the
Information field of PPP Data Link Layer frames where
the Protocol field indicates type hex 802B (IPX
Control Protocol).
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Code field
Only Codes 1 through 7 (Configure-Request, Configure-
Ack, Configure-Nak, Configure-Reject, Terminate-
Request, Terminate-Ack and Code-Reject) are used.
Other Codes should be treated as unrecognized and should
result in CodeRejects.
Timeouts
IPXCP packets may not be exchanged until PPP has
reached the Network- Layer Protocol phase. An
implementation should be prepared to wait for
Authentication and Link Quality Determination to finish
before timing out waiting for a Configure-Ack or other
response. It is suggested that an implementation give
up only after user intervention or a configurable amount
of time.
Configuration Option Types
Since IPX is intended to use a variety of data link
mechanisms transparently (emulated or otherwise), end-
to-end knowledge of IPX specifics are included in the IPX
WAN protocol defined in [Ref 5] (which includes use over
PPP). Therefore no configuration options are used.
Sending IPX Datagrams
Before any IPX packets may be communicated, PPP must
reach the Network-Layer Protocol phase, and the IPX
Control Protocol must reach the Opened state.
Exactly one IPX packet is encapsulated in the
Information field of PPP Data Link Layer frames where
the Protocol field indicates type hex 002B (IPX Protocol).
The maximum length of an IPX packet transmitted over a
PPP link is the same as the maximum length of the
Information field of a PPP data link layer frame.
3. IPXCP Configuration Options
There are currently no configuration options defined for the
IPX Control Protocol.
4. Security Considerations
Security issues are not discussed in this memo.
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5. References
[1] Simpson, W. A., "The Point-to-Point Protocol for the
Transmission of Multi-Protocol of Datagrams Over Point-
toPoint Links", RFC 1331, May 1992.
[2] Postel, J., "Internet Protocol", RFC 791,
USC/Information Sciences Institute, September 1981.
[3] Reynolds, J., Postel,J., "Assigned Numbers", RFC 1060,
USC/Information Sciences Institute, March 1990.
[4] Novell, Inc., "NetWare System Interface Technical
Overview", Novell Part Number 883-001143-001
[5] Allen, M., "Novell IPX Over Various WAN Media", Novell,
Inc., June 1992.
6. Acknowledgments
Most of the text in this document was taken from RFC 1331,
May 1992.
7. Obsoletes
This document obsoletes an earlier document produced in
January 1992 which limited this Internet Draft to IPX with a
RIP/SAP only routing protocol. This document does not impose
this restriction, but instead references an Informational RFC
describing how Novell operates over ALL WAN media and
negotiates the routing protocol at an IPX level using IPX
packets [Ref 5].
8. Expiration Date
The expiration date of this document is 12/15/92.
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9. Contact Points
Chair's Address:
The working group can be contacted via the current chair:
Brian Lloyd
Lloyd & Associates
3420 Sudbury Road
Cameron Park, California 95682
Phone: (916) 676-1147
EMail: brian@ray.lloyd.com
Author's Address:
Michael Allen
Novell, Inc.,
2180, Fortune Drive,
San Jose, CA 95131
EMail: MALLEN@NOVELL.COM
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