RFC 2153

PPP Vendor Extensions

📅 published May 1997, from ietf

RFC 2153: PPP Vendor Extensions 🎀

Okay bestie, let's start with the paperwork 💅 This is RFC 2153, written by W. Simpson of DayDreamer in May 1997. It's Informational, so it's an FYI for the Internet community and not an official standard 🫶 It updates RFCs 1661 and 1962 ✨

Status of this Memo 📋

This document is for information only, so it's not specifying any kind of Internet standard 🌸 Distribution of this memo is unlimited 🦋

Abstract 🌈

Okay, so the Point-to-Point Protocol (PPP) [1] is the standard way to shove multi-protocol datagrams across point-to-point links 🚀 It has an extensible Link Control Protocol (LCP) for setting up, configuring, and testing the data-link connection, plus a whole family of Network Control Protocols (NCPs) for setting up and configuring different network-layer protocols 💜

This document defines a general mechanism for proprietary vendor extensions 🧚 It's the vendor's own little secret menu, and it's giving main character energy 👑

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

1. Control Packets 📦

Okay so the Packet format and basic facilities are already defined for LCP [1] and the related NCPs 🌟

The up-to-date values of the LCP Code field are in the latest "Assigned Numbers" [2] 📚 This document is only about this one value:

    0      Vendor Specific

1.1. Vendor Specific Packet 💖

Description

Some implementors might not need or want to publish their proprietary algorithms and attributes, and that's valid 💅 This mechanism lets them specify all of that without making the IANA handle a pile of proprietary number requests 🫶

Vendor Specific packets MAY be sent at any time, including before LCP has reached the Opened state ✨

Here's how the sender builds one: it transmits an 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 whatever data you want. Just don't go past the default MRU minus twelve 🔥

When a Vendor Specific packet is received, that causes the RXR or RUC event. The response to a Vendor Specific packet is vendor specific 🙈

If a Code-Reject comes back for the packet, that SHOULD generate the RXJ+ (permitted) event 🍓

Rationale

This is defined as a general feature of all PPP Control Protocols, so vendors can't secretly self-assign Code numbers and cause future conflicts 🌸

Here's the summary of the Vendor Specific packet format. The fields go 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 every Vendor Specific packet you send 💅

Length

>= 12

When the Length is twelve, there's no Value(s) field 🦋

Magic-Number

The Magic-Number field is four octets, and it helps detect 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 the full scoop 💜

OUI

Three octets: this is 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. It indicates a sub-type for the OUI. There's no standardization for this field, so each OUI implements its own values 🎀

The vendor is allowed to extend the Kind field 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 ⚙️

Okay, so the Configuration Option format and basic options are already defined for LCP [1] 🌸

The up-to-date values of the LCP Option Type field are in the most recent "Assigned Numbers" [2] 📖 This document is only about this one value:

    0      Vendor-Specific

2.1. Vendor-Specific Option 🦋

Description

Same energy as before: some implementors might not need or want to publish their proprietary algorithms and attributes, and this mechanism lets them specify those things 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 a general feature of all PPP Control Protocols, so vendors can't secretly self-assign Type numbers and cause future conflicts 🌟

Here's the summary of the Vendor-Specific Configuration Option format. The fields go from left to right 💖

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |              OUI
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          ...      |     Kind      |  Value(s) ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

Type

0

Length

>= 6

When the Length is six, there's no Value(s) field 🧚

OUI

Three octets: this is 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. It indicates a sub-type for the OUI. There's no standardization for this field, so each OUI implements its own values 🎀

The vendor is allowed to extend the Kind field 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 the organization that administers the meaning of the message 💜 This OUI is based on IEEE 802 vendor assignments 🌸

For IEEE contact details on getting an OUI, check [RFC-1700] 📬 Vendors that want to use their IEEE 802 OUI for PPP Vendor Extensions should also register the OUI with IANA 🦋

Or, if a vendor doesn't otherwise need an IEEE-assigned OUI, they can request a PPP-specific OUI from IANA instead 🍓 That OUI shall be assigned from the 'CF0000' series. It has both the "locally-assigned" and "broadcast/multicast" bits set to 1. In other words, the least significant two bits of the most significant octet are both set to 1 🌈

Here's how it looks in memory, with bits transmitted right-to-left within octets and octets transmitted left-to-right 🎀

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |1 1 0 0 1 1 1 1|x x x x x x x x|x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                | |
                | Multicast
                Local

Rationale

This is defined for vendors that can't use IEEE assignments, like software-only vendors 💻

It's 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, RFC 1661, 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) 👑

📦 where this page comes from

ietf: rfc2153 1997-05
💖 girlified by claude-haiku-5-5 on 2026-10-15: a language model's rewrite of the original, under its terms