Network Working Group W. Simpson
Request for Comments: 2153 DayDreamer
Updates: RFCs 1661, 1962 May 1997
Category: Informational
PPP Vendor Extensions
Status of this Memo
This document provides information for the Internet community. It
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
Abstract
The Point-to-Point Protocol (PPP) [1] provides a standard method for
transporting multi-protocol datagrams over point-to-point links. PPP
defines an extensible Link Control Protocol (LCP) for establishing,
configuring, and testing the data-link connection; and a family of
Network Control Protocols (NCPs) for establishing and configuring
different network-layer protocols.
This document defines a general mechanism for proprietary vendor
extensions.
Simpson Informational [Page i]
RFC2153 PPP vendor extensions May 1997
Table of Contents
1. Control Packets ....................................... 1
1.1 Vendor Specific Packet .......................... 1
2. Configuration Options ................................. 3
2.1 Vendor-Specific Option .......................... 3
3. Organizationally Unique Identifiers ................... 4
SECURITY CONSIDERATIONS ...................................... 5
REFERENCES ................................................... 5
CONTACTS ..................................................... 6
Simpson Informational [Page ii]
RFC2153 PPP vendor extensions May 1997
1. Control Packets
The Packet format and basic facilities are already defined for LCP
[1] and related NCPs.
Up-to-date values of the LCP Code field are specified in the most
recent "Assigned Numbers" [2]. This document concerns the following
values:
0 Vendor Specific
1.1. Vendor Specific Packet
Description
Some implementors might not need nor want to publish their
proprietary algorithms and attributes. This mechanism is
available to specify these without encumbering the IANA with
proprietary number requests.
Vendor Specific packets MAY be sent at any time, including before
LCP has reached the Opened state.
The sender transmits a LCP or NCP packet with the Code field set
to 0 (Vendor Specific), the Identifier field set, the local
Magic-Number (if any) inserted, the OUI and Kind fields set, and
the Value(s) field filled with any desired data, but not exceeding
the default MRU minus twelve.
Receipt of a Vendor Specific packet causes the RXR or RUC event.
The response to the Vendor Specific packet is vender specific.
Receipt of a Code-Reject for the packet SHOULD generate the RXJ+
(permitted) event.
Rationale:
This is defined as general feature of all PPP Control Protocols,
to avoid future conflicts in vendor secretly self-assigned Code
numbers.
A summary of the Vendor Specific packet format is shown below. The
fields are transmitted from left to right.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Code Identifier Length
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Magic-Number
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
OUI Kind
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Value(s) ...
+-+-+-+-+-+-+-+-+
Code
0 for Vendor Specific
Identifier
The Identifier field MUST be changed for each Vendor Specific
packet sent.
Length
>= 12
When the Length is twelve, no Value(s) field is present.
Magic-Number
The Magic-Number field is four octets and aids in detecting links
that are in the looped-back condition. Until the Magic-Number
Configuration Option has been successfully negotiated, the Magic-
Number MUST be transmitted as zero. See the Magic-Number
Configuration Option for further eXPlanation.
OUI
three octets. The vendor"s Organizationally Unique Identifier.
The bits within the octet are in canonical order, and the most
significant octet is transmitted first.
Kind
one octet. Indicates a sub-type for the OUI. There is no
standardization for this field. Each OUI implements its own
values.
The Kind field may be extended by the vendor to include zero or
more octets of the Value(s) field.
Value(s)
Zero or more octets. The details are implementation specific.
2. Configuration Options
The Configuration Option format and basic options are already defined
for LCP [1].
Up-to-date values of the LCP Option Type field are specified in the
most recent "Assigned Numbers" [2]. This document concerns the
following values:
0 Vendor-Specific
2.1. Vendor-Specific Option
Description
Some implementors might not need nor want to publish their
proprietary algorithms and attributes. This mechanism is
available to specify these without encumbering the IANA with
proprietary number requests.
Before accepting this option, the implementation must verify that
the Organizationally Unique Identifier and Kind specify a known
mechanism, and that any vendor specific negotiation values are
fully understood.
Rationale:
This is defined as general feature of all PPP Control Protocols,
to avoid future conflicts in vendor secretly self-assigned Type
numbers.
A summary of the Vendor-Specific Configuration Option format is shown
below. The fields are transmitted from left to right.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Length OUI
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... Kind Value(s) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Type
0
Length
>= 6
When the Length is six, no Value(s) field is present.
OUI
three octets. The vendor"s Organizationally Unique Identifier.
The bits within the octet are in canonical order, and the most
significant octet is transmitted first.
Kind
one octet. Indicates a sub-type for the OUI. There is no
standardization for this field. Each OUI implements its own
values.
The Kind field may be extended by the vendor to include zero or
more octets of the Value(s) field.
Value(s)
Zero or more octets. The details are implementation specific.
3. Organizationally Unique Identifiers
The three-octet Organizationally Unique Identifier (OUI) identifies
an organization that administers the meaning of the message. This
OUI is based on IEEE 802 vendor assignments.
IEEE contact details for assignment of an OUI are given in [RFC-
1700]. Vendors that desire to use their IEEE 802 OUI for PPP Vendor
Extensions should also register the OUI with IANA.
In the alternative, a vendor that does not otherwise need an IEEE
assigned OUI can request a PPP specific OUI from IANA. This OUI
shall be assigned from the "CF0000" series. This has both the
"locally-assigned" and "broadcast/multicast" bits set to 1; that is,
the least significant two bits of the most significant octet are both
set to 1.
Appearance in memory, bits transmitted right-to-left within octets,
octets transmitted left-to-right:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1 1 0 0 1 1 1 1x x x x x x x xx x x x x x x x
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Multicast
Local
Rationale:
This is defined for vendors that are not able to use IEEE
assignments, such as software-only vendors.
It is not clear how the IEEE assigns blocks. In some instances,
the "locally-assigned" bit is known to have been used.
However, multicast has no meaning in PPP. Therefore, an IEEE
assigned OUI would have the multicast bit cleared to 0.
The "CF0000" series was arbitrarily chosen to match the PPP NLPID
"CF", as a matter of mnemonic convenience.
Security Considerations
Security issues are not discussed in this document.
References
[1] Simpson, W., Editor, "The Point-to-Point Protocol (PPP)", STD
51, RFC1661, DayDreamer, July 1994.
[2] Reynolds, J.K., Postel, J.B., "Assigned Numbers", RFC-1700,
July 1992.
Contacts
Comments about this document should be discussed on the ietf-
ppp@merit.edu mailing list.
This document was reviewed by the Point-to-Point Protocol Working
Group of the Internet Engineering Task Force (IETF). The working
group can be contacted via the current chair:
Karl Fox
Ascend Communications
655 Metro Place South, Suite 379
Dublin, Ohio 43017
karl@Ascend.com
Questions about this document can also be directed to:
William Allen Simpson
DayDreamer
Computer Systems Consulting Services
1384 Fontaine
Madison Heights, Michigan 48071
wsimpson@UMich.edu
wsimpson@GreenDragon.com (preferred)