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Close Encounters of the ICMP Type 2 Kind (Near Misses with ICMPv6 Packet Too Big (PTB)) (RFC7690) Disclosure Number: IPCOM000245042D
Original Publication Date: 2016-Jan-01
Included in the Prior Art Database: 2016-Feb-06
Document File: 18 page(s) / 19K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. Byerly: AUTHOR [+3]


Operators of popular Internet services face complex challenges associated with scaling their infrastructure. One scaling approach is to utilize equal-cost multipath (ECMP) routing to perform stateless distribution of incoming TCP or UDP sessions to multiple servers or to middle boxes such as load balancers. Distribution of traffic in this manner presents a problem when dealing with ICMP signaling. Specifically, an ICMP error is not guaranteed to hash via ECMP to the same destination as its corresponding TCP or UDP session. A case where this is particularly problematic operationally is path MTU discovery (PMTUD) [RFC1981].

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Internet Engineering Task Force (IETF)                         M. Byerly Request for Comments: 7690                                        Fastly Category: Informational                                          M. Hite ISSN: 2070-1721                                                 Evernote                                                               J. Jaeggli                                                                   Fastly                                                             January 2016

                 Close Encounters of the ICMP Type 2 Kind              (Near Misses with ICMPv6 Packet Too Big (PTB))


   This document calls attention to the problem of delivering ICMPv6    type 2 "Packet Too Big" (PTB) messages to the intended destination    (typically the server) in ECMP load-balanced or anycast network    architectures.  It discusses operational mitigations that can be    employed to address this class of failures.

Status of This Memo

   This document is not an Internet Standards Track specification; it is    published for informational purposes.

   This document is a product of the Internet Engineering Task Force    (IETF).  It represents the consensus of the IETF community.  It has    received public review and has been approved for publication by the    Internet Engineering Steering Group (IESG).  Not all documents    approved by the IESG are a candidate for any level of Internet    Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,    and how to provide feedback on it may be obtained at

 Byerly, et al.                Informational                     [Page 1]
 RFC 7690                 Misses with ICMPv6 PTB             January 2016

 Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the    document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal    Provisions Relating to IETF Documents    ( 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 Lice...