IP Fragmentation Considered Fragile
draft-ietf-intarea-frag-fragile-17

Document Type Active Internet-Draft (intarea WG)
Last updated 2019-10-10 (latest revision 2019-09-30)
Replaces draft-bonica-intarea-frag-fragile
Stream IETF
Intended RFC status Best Current Practice
Formats plain text xml pdf htmlized bibtex
Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Joel Halpern
Shepherd write-up Show (last changed 2019-07-09)
IESG IESG state RFC Ed Queue
Consensus Boilerplate Yes
Telechat date
Responsible AD Suresh Krishnan
Send notices to Joel Halpern <joel.halpern@ericsson.com>, Joel Halpern <jmh@joelhalpern.com>
IANA IANA review state Version Changed - Review Needed
IANA action state No IANA Actions
RFC Editor RFC Editor state MISSREF
Internet Area WG                                               R. Bonica
Internet-Draft                                          Juniper Networks
Intended status: Best Current Practice                          F. Baker
Expires: April 2, 2020                                      Unaffiliated
                                                               G. Huston
                                                                   APNIC
                                                               R. Hinden
                                                    Check Point Software
                                                                O. Troan
                                                                   Cisco
                                                                 F. Gont
                                                            SI6 Networks
                                                      September 30, 2019

                  IP Fragmentation Considered Fragile
                   draft-ietf-intarea-frag-fragile-17

Abstract

   This document describes IP fragmentation and explains how it
   introduces fragility to Internet communication.

   This document also proposes alternatives to IP fragmentation and
   provides recommendations for developers and network operators.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 2, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Bonica, et al.            Expires April 2, 2020                 [Page 1]
Internet-Draft          IP Fragmentation Fragile          September 2019

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  IP Fragmentation  . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Links, Paths, MTU and PMTU  . . . . . . . . . . . . . . .   3
     2.2.  Fragmentation Procedures  . . . . . . . . . . . . . . . .   6
     2.3.  Upper-Layer Reliance on IP Fragmentation  . . . . . . . .   6
   3.  Increased Fragility . . . . . . . . . . . . . . . . . . . . .   7
     3.1.  Virtual Reassembly  . . . . . . . . . . . . . . . . . . .   7
     3.2.  Policy-Based Routing  . . . . . . . . . . . . . . . . . .   8
     3.3.  Network Address Translation (NAT) . . . . . . . . . . . .   9
     3.4.  Stateless Firewalls . . . . . . . . . . . . . . . . . . .   9
     3.5.  Equal Cost Multipath, Link Aggregate Groups and Stateless
           Load-Balancers  . . . . . . . . . . . . . . . . . . . . .  10
     3.6.  IPv4 Reassembly Errors at High Data Rates . . . . . . . .  11
     3.7.  Security Vulnerabilities  . . . . . . . . . . . . . . . .  11
     3.8.  PMTU Blackholing Due to ICMP Loss . . . . . . . . . . . .  12
       3.8.1.  Transient Loss  . . . . . . . . . . . . . . . . . . .  13
       3.8.2.  Incorrect Implementation of Security Policy . . . . .  13
       3.8.3.  Persistent Loss Caused By Anycast . . . . . . . . . .  14
       3.8.4.  Persistent Loss Caused By Unidirectional Routing  . .  14
     3.9.  Blackholing Due To Filtering or Loss  . . . . . . . . . .  14
   4.  Alternatives to IP Fragmentation  . . . . . . . . . . . . . .  15
     4.1.  Transport Layer Solutions . . . . . . . . . . . . . . . .  15
     4.2.  Application Layer Solutions . . . . . . . . . . . . . . .  17
   5.  Applications That Rely on IPv6 Fragmentation  . . . . . . . .  17
     5.1.  Domain Name Service (DNS) . . . . . . . . . . . . . . . .  18
     5.2.  Open Shortest Path First (OSPF) . . . . . . . . . . . . .  18
     5.3.  Packet-in-Packet Encapsulations . . . . . . . . . . . . .  18
     5.4.  UDP Applications Enhancing Performance  . . . . . . . . .  19
Show full document text