RFC 4937

IANA Considerations for PPP over Ethernet (PPPoE)

📅 published June 2007, from ietf

RFC 4937: IANA Considerations for PPP over Ethernet (PPPoE) 🎀

okay bestie, this one's a short and sweet IANA doc, and it's giving "keep the registries tidy" energy 💅

  • Request for Comments: 4937
  • Network Working Group
  • Authors: P. Arberg (Redback Networks) and V. Mammoliti (Cisco Systems) 🧚
  • Category: Informational
  • Date: June 2007
  • Obsoletes / Updates: the header doesn't list any, so this one doesn't obsolete or update anything else 🌸

Status of This Memo ✨

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

Copyright (C) The IETF Trust (2007).

Abstract 🦋

This document describes the IANA considerations for the PPP over Ethernet (PPPoE) protocol.

Table of Contents 💜

1. Introduction ....................................................2
   1.1. Terminology ................................................2
   1.2. Specification of Requirements ..............................2
2. IANA Considerations .............................................2
   2.1. Registration Policies for PPPoE TAG Values .................2
   2.2. Reserved PPPoE TAG Values ..................................3
   2.3. Registration Policies for PPPoE Code Fields ................3
   2.4. Reserved PPPoE Code fields .................................4
3. Security Considerations .........................................4
4. References ......................................................4
   4.1. Normative References .......................................4
   4.2. Informative References .....................................4

1. Introduction 🌸

okay so this doc is basically the guidance for IANA (the folks who keep the official number lists) on registering values for PPP over Ethernet, which is PPPoE as defined in [RFC2516]. it's done following BCP 26, [RFC2434]. it also reserves the PPPoE TAG values and PPPoE packet Code fields that are already out there being used on the Internet. iconic behavior 🔥

1.1. Terminology 🧚

these terms have the meanings BCP 26 gives them: "name space" and "registration".

the policy here is also borrowed from BCP 26: "First Come First Served".

1.2. Specification of Requirements 💅

the doc uses a handful of words to signal what the spec requires, and they're usually capitalized. the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be read as described in [RFC2119]. 🫶

2. IANA Considerations 👑

PPPoE, as defined in [RFC2516], has two name spaces that need registration: the PPPoE TAG and the PPPoE Code field. two things to keep track of, periodt 💖

2.1. Registration Policies for PPPoE TAG Values 🎀

IANA has set up a registry called "PPPoE TAG Values". these are 16-bit values. any TAG values already in use are reserved in this document. every other TAG value between 0 and 65535 gets assigned by IANA under the "First Come First Served" policy from [RFC2434]. ✨

a TAG-Name, a description of the usage, and a point of contact MUST be provided for any assignment from this registry. a document reference SHOULD also be provided. 🌈

2.2. Reserved PPPoE TAG Values 💜

here's the reserved list, copied exactly as it appears:

TAG Value     TAG Name              Tag Description         Reference
-----------   -------------------   ---------------------   ---------
0    0x0000   End-Of-List           See the reference       [RFC2516]

257  0x0101   Service-Name          See the reference       [RFC2516]
258  0x0102   AC-Name               See the reference       [RFC2516]
259  0x0103   Host-Uniq             See the reference       [RFC2516]
260  0x0104   AC-Cookie             See the reference       [RFC2516]
261  0x0105   Vendor-Specific       See the reference       [RFC2516]
262  0x0106   Credits               See the reference       [RFC4938]
263  0x0107   Metrics               See the reference       [RFC4938]
264  0x0108   Sequence Number       See the reference       [RFC4938]

272  0x0110   Relay-Session-Id      See the reference       [RFC2516]
273  0x0111   HURL                  See the reference       [CARREL]
274  0x0112   MOTM                  See the reference       [CARREL]

288  0x0120   PPP-Max-Payload       See the reference       [RFC4638]
289  0x0121   IP_Route_Add          See the reference       [CARREL]

513  0x0201   Service-Name-Error    See the reference       [RFC2516]
514  0x0202   AC-System-Error       See the reference       [RFC2516]
515  0x0203   Generic-Error         See the reference       [RFC2516]

2.3. Registration Policies for PPPoE Code Fields 🦋

IANA has set up a registry called PPPoE Active Discovery Code fields. these are 8-bit values. any PPPoE Code fields already in use are reserved in this document. every other Code value between 0 and 255 gets assigned by IANA under the "First Come First Served" policy from [RFC2434]. 🍓

a PPPoE Active Discovery packet name, a description of the usage, and a point of contact MUST be provided for any assignment from this registry. 🙈

a document reference SHOULD also be provided. 💅

2.4. Reserved PPPoE Code fields 💖

and the reserved Code list:

Code      PPPoE Packet Name              Description        Reference
--------  -----------------------------  -----------------  ---------
0   0x00  PPP Session Stage              See the reference  [RFC2516]

7   0x07  PADO, Offer                    See the reference  [RFC2516]
9   0x09  PADI, Initiation               See the reference  [RFC2516]

10  0x0a  PADG, Session-Grant            See the reference  [RFC4938]
11  0x0b  PADC, Session-Credit Response  See the reference  [RFC4938]
12  0x0c  PADQ, Quality                  See the reference  [RFC4938]

25  0x19  PADR, Request                  See the reference  [RFC2516]
101 0x65  PADS, Session-confirmation     See the reference  [RFC2516]

167 0xa7  PADT, Terminate                See the reference  [RFC2516]

211 0xd3  PADM, Message                  See the reference  [CARREL]
212 0xd4  PADN, Network                  See the reference  [CARREL]

3. Security Considerations 🔥

ok this part is serious, so read it closely 🙈 This document focuses on IANA considerations for the PPPoE protocol, and as such, should help remove the possibility of the same PPPoE code field and PPPoE TAG value being used for different functionalities. so the registries are the security story here, lowkey clutch 💀

4. References 🧚

4.1. Normative References 🌈

  • [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
  • [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
  • [RFC2516] Mamakos, L., Lidl, K., Evarts, J., Carrel, D., Simone, D., and R. Wheeler, "A Method for Transmitting PPP Over Ethernet (PPPoE)", RFC 2516, February 1999.

4.2. Informative References 💜

  • [CARREL] Carrel D., Simone D., Ho C. and T. Stoner, "Extensions to a Method for Transmitting PPP Over Ethernet (PPPoE)", Work in Progress.
  • [RFC4938] Berry, B. and H. Holgate, "PPP Over Ethernet (PPPoE) Extensions for Credit Flow and Link Metrics", RFC 4938, June 2007.
  • [RFC4638] Arberg, P., Kourkouzelis, D., Duckett, M., Anschutz, T., and J. Moisand, "Accommodating a Maximum Transit Unit/Maximum Receive Unit (MTU/MRU) Greater Than 1492 in the Point-to-Point Protocol over Ethernet (PPPoE)", RFC 4638, September 2006.

Authors' Addresses 🫶

Peter Arberg Redback Networks, Inc. 300 Holger Way San Jose, CA 95134 USA EMail: parberg@redback.com

Vince Mammoliti Cisco Systems, Inc. 181 Bay Street, Suite 3400 Toronto, Ontario, M5J 2T3 Canada EMail: vince@cisco.com

Copyright (C) The IETF Trust (2007).

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