IP Fragmentation Considered Fragile
draft-ietf-intarea-frag-fragile-04

Document Type Active Internet-Draft (intarea WG)
Last updated 2018-11-27
Replaces draft-bonica-intarea-frag-fragile
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Internet Area WG                                               R. Bonica
Internet-Draft                                          Juniper Networks
Intended status: Best Current Practice                          F. Baker
Expires: May 31, 2019                                       Unaffiliated
                                                               G. Huston
                                                                   APNIC
                                                               R. Hinden
                                                    Check Point Software
                                                                O. Troan
                                                                   Cisco
                                                                 F. Gont
                                                            SI6 Networks
                                                       November 27, 2018

                  IP Fragmentation Considered Fragile
                   draft-ietf-intarea-frag-fragile-04

Abstract

   This document describes IP fragmentation and explains how it reduces
   the reliability of 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
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   This Internet-Draft will expire on May 31, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Bonica, et al.            Expires May 31, 2019                  [Page 1]
Internet-Draft          IP Fragmentation Fragile           November 2018

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  IP Fragmentation  . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Links, Paths, MTU and PMTU  . . . . . . . . . . . . . . .   3
     2.2.  Fragmentation Procedures  . . . . . . . . . . . . . . . .   5
     2.3.  Upper-Layer Reliance on IP Fragmentation  . . . . . . . .   6
   3.  Requirements Language . . . . . . . . . . . . . . . . . . . .   7
   4.  Reduced Reliability . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Policy-Based Routing  . . . . . . . . . . . . . . . . . .   7
     4.2.  Network Address Translation (NAT) . . . . . . . . . . . .   8
     4.3.  Stateless Firewalls . . . . . . . . . . . . . . . . . . .   8
     4.4.  Stateless Load Balancers  . . . . . . . . . . . . . . . .   9
     4.5.  IPv4 Reassembly Errors at High Data Rates . . . . . . . .  10
     4.6.  Security Vulnerabilities  . . . . . . . . . . . . . . . .  10
     4.7.  Blackholing Due to ICMP Loss  . . . . . . . . . . . . . .  11
       4.7.1.  Transient Loss  . . . . . . . . . . . . . . . . . . .  12
       4.7.2.  Incorrect Implementation of Security Policy . . . . .  12
       4.7.3.  Persistent Loss Caused By Anycast . . . . . . . . . .  13
     4.8.  Blackholing Due To Filtering  . . . . . . . . . . . . . .  13
   5.  Alternatives to IP Fragmentation  . . . . . . . . . . . . . .  14
     5.1.  Transport Layer Solutions . . . . . . . . . . . . . . . .  14
     5.2.  Application Layer Solutions . . . . . . . . . . . . . . .  15
   6.  Applications That Rely on IPv6 Fragmentation  . . . . . . . .  16
     6.1.  DNS . . . . . . . . . . . . . . . . . . . . . . . . . . .  16
     6.2.  OSPF  . . . . . . . . . . . . . . . . . . . . . . . . . .  17
     6.3.  Packet-in-Packet Encapsulations . . . . . . . . . . . . .  17
     6.4.  Licklider Transmission Protocol (LTP) . . . . . . . . . .  17
   7.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .  18
     7.1.  For Application Developers  . . . . . . . . . . . . . . .  18
     7.2.  For System Developers . . . . . . . . . . . . . . . . . .  18
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