Architectural Considerations of IP Anycast
draft-iab-anycast-arch-implications-11

The information below is for an old version of the document
Document Type Active Internet-Draft
Last updated 2013-10-21
Stream IAB
Intended RFC status Informational
Formats plain text pdf html bibtex
Additional URLs
Stream IAB state Community Review
Consensus Boilerplate Unknown
RFC Editor Note (None)
Internet Engineering Task Force                             D. McPherson
Internet-Draft                                            Verisign, Inc.
Intended status: Informational                                   D. Oran
Expires: April 25, 2014                                    Cisco Systems
                                                               D. Thaler
                                                   Microsoft Corporation
                                                            E. Osterweil
                                                          Verisign, Inc.
                                                        October 22, 2013

               Architectural Considerations of IP Anycast
                 draft-iab-anycast-arch-implications-11

Abstract

   This memo discusses architectural implications of IP anycast, and
   provides some historical analysis of anycast use by various IETF
   protocols.

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 25, 2014.

Copyright Notice

   Copyright (c) 2013 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
   (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

McPherson, et al.        Expires April 25, 2014                 [Page 1]
Internet-Draft      Arch Considerations of IP Anycast       October 2013

   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.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Anycast History . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Anycast in IPv6 . . . . . . . . . . . . . . . . . . . . .   6
     2.3.  DNS Anycast . . . . . . . . . . . . . . . . . . . . . . .   6
     2.4.  BCP 126 on Operation of Anycast Services  . . . . . . . .   8
   3.  Principles  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     3.1.  Layering and Resiliency . . . . . . . . . . . . . . . . .   8
     3.2.  Anycast Addresses as Destinations . . . . . . . . . . . .   9
     3.3.  Anycast Addresses as Sources  . . . . . . . . . . . . . .  10
     3.4.  Service Discovery . . . . . . . . . . . . . . . . . . . .  10
   4.  Analysis  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     4.1.  Regarding Widespread Anycast Use  . . . . . . . . . . . .  11
     4.2.  Transport Implications  . . . . . . . . . . . . . . . . .  12
     4.3.  Stateful Firewalls, Middleboxes and Anycast . . . . . . .  12
     4.4.  Security Considerations . . . . . . . . . . . . . . . . .  12
     4.5.  Deployment Considerations . . . . . . . . . . . . . . . .  15
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   6.  Conclusions . . . . . . . . . . . . . . . . . . . . . . . . .  17
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  17
   8.  Informative References  . . . . . . . . . . . . . . . . . . .  17
   Appendix A.  IAB Members at the Time of Approval  . . . . . . . .  20
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

1.  Overview

   IP anycast is a technique with a long legacy, with interesting
   engineering challenges associated with it.  However, at its core it
   is a relatively simple concept.  As described in BCP 126 [RFC4786],
   the general form of IP anycast is the practice of making a particular
   Service Address available in multiple, discrete, autonomous
   locations, such that datagrams sent are routed to one of several
   available locations.

McPherson, et al.        Expires April 25, 2014                 [Page 2]
Internet-Draft      Arch Considerations of IP Anycast       October 2013

   IP anycast is used for at least one critical Internet service, that
Show full document text