Accommodating a Maximum Transit Unit/Maximum Receive Unit (MTU/MRU) Greater Than 1492 in the Point-to-Point Protocol over Ethernet (PPPoE)
RFC 4638

Approval announcement
Draft of message to be sent after approval:

From: The IESG <>
To: IETF-Announce <>
Cc: Internet Architecture Board <>,
    RFC Editor <>, 
    pppext mailing list <>, 
    pppext chair <>
Subject: Document Action: 'Accommodating an MTU/MRU greater than 
         1492 in PPPoE' to Informational RFC 

The IESG has approved the following document:

- 'Accommodating an MTU/MRU greater than 1492 in PPPoE '
   <draft-arberg-pppoe-mtu-gt1492-04.txt> as an Informational RFC

This document is the product of the Point-to-Point Protocol Extensions 
Working Group. 

The IESG contact persons are Mark Townsley and Jari Arkko.

A URL of this Internet-Draft is:

Technical Summary
   Point-to-Point Protocol Over Ethernet (PPPoE), as described in RFC
   2516 [1], mandates a maximum negotiated MRU of 1492. This document 
   outlines a solution to relax that restriction and allow a maximum 
   negotiated MRU greater than 1492 to minimize fragmentation in next 
   generation broadband networks. 
Working Group Summary
   "The consensus seems relatively weak to me, with a handful of
   PPPoE advocates strongly voicing support for the draft, and
   relative skepticism or apathy elsewhere.  As it seems to be a
   minor change to an Informational protocol, and in general should
   enable some folks who are currently plagued with MTU problems to
   have a better experience, I think it's mostly helpful."

Protocol Quality
   This spec was reviewed by the pppext WG and Mark Townsley.

Note to RFC Editor


    No IANA action is required.


   This document defines a new value in a space that currently has no
   IANA registry.  There is work in progress to define a registry [IANA],
   and that document already contains the value assigned here.  No IANA
   action is required for this document.

Please include an informative reference to draft-arberg-pppoe-iana-01.txt for


This allows it to test that the receiving side and any intermediate
equipment can handle such packet size.


This allows it to test that the receiving side and any intermediate
Ethernet segments and equipment can handle such packet size.


... jumbo frames on Ethernet segments


... frames with Ethernet packet format, but exceeding the maximum packet
lengthas defined by [REFERENCE - IEEE 802.3]

Please include the following reference for the above change:
[802.3-2005]   Institute of Electrical and Electronic Engineers, IEEE
   Std 802.3-2005, "IEEE Standard for Carrier Sense Multiple Access with
   Collision Detection (CSMA/CD) Access Method and Physical Layer
   Specifications - Draft amendment to - Information technology -
   Telecommunications and information exchange between systems - Local
   and metropolitan area networks - Specific requirements - Part 3:
   Carrier sense multiple access with collision detection (CSMA/CD)
   access method and physical layer specifications - Media Access
   Control Parameters, Physical Layers and Management Parameters",
   December 2005.


    As of this writing, no current IEEE standard supports the use of
    "jumbo frames" (MTU greater than 1500).  Although this document
    contains recommended mechanisms to detect problems in the path,
    interoperability and reliability of non-standard extensions cannot
    be assured.  Both implementors and users of the protocol described
    here should exercise caution in its use.