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Using Only Link-Local Addressing Inside an IPv6 Network
draft-ietf-opsec-lla-only-07

Document type: Active Internet-Draft (opsec WG)
Document stream: IETF
Last updated: 2014-04-13 (latest revision 2014-02-13)
Intended RFC status: Informational
Other versions: plain text, xml, pdf, html

IETF State: Submitted to IESG for Publication
Consensus: Yes
Document shepherd: Gunter Van de Velde
Shepherd Write-Up: Last changed 2014-03-13

IESG State: Waiting for AD Go-Ahead::AD Followup
IANA Review State: IANA OK - No Actions Needed
IANA Action State: None
Responsible AD: Joel Jaeggli
Send notices to: opsec-chairs@tools.ietf.org, draft-ietf-opsec-lla-only@tools.ietf.org

OPsec Working Group                                         M. Behringer
Internet-Draft                                                 E. Vyncke
Intended status: Informational                                     Cisco
Expires: August 17, 2014                               February 13, 2014

        Using Only Link-Local Addressing Inside an IPv6 Network
                      draft-ietf-opsec-lla-only-07

Abstract

   In an IPv6 network it is possible to use only link-local addresses on
   infrastructure links between routers.  This document discusses the
   advantages and disadvantages of this approach to help the decision
   process for a given network.

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 August 17, 2014.

Copyright Notice

   Copyright (c) 2014 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
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   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.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Using Link-Local Address on Infrastructure Links  . . . . . .   2
     2.1.  The Approach  . . . . . . . . . . . . . . . . . . . . . .   2
     2.2.  Advantages  . . . . . . . . . . . . . . . . . . . . . . .   3
     2.3.  Caveats . . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.4.  Internet Exchange Points  . . . . . . . . . . . . . . . .   6
     2.5.  Summary . . . . . . . . . . . . . . . . . . . . . . . . .   7
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   6.  Informative References  . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   An infrastructure link between a set of routers typically does not
   require global or unique local addresses [RFC4193].  Using only link-
   local addressing on such links has a number of advantages.  For
   example, that routing tables do not need to carry link addressing,
   and can therefore be significantly smaller.  This helps to decrease
   failover times in certain routing convergence events.  An interface
   of a router is also not reachable beyond the link boundaries,
   therefore reducing the attack horizon.

   This document discusses the advantages and caveats of this approach.

2.  Using Link-Local Address on Infrastructure Links

   This document discusses the approach of using only link-local
   addresses (LLA) on all router interfaces on infrastructure links.
   Routers don't typically need to receive packets from hosts or nodes
   outside the network.  For a network operator, there may be reasons to
   use greater than link-local scope addresses on infrastructure
   interfaces for certain operational tasks, such as pings to an
   interface or traceroutes across the network.  This document discusses
   such cases and proposes alternative procedures.

2.1.  The Approach

   In this approach neither globally routed IPv6 addresses nor unique
   local addresses are configured on infrastructure links.  In the
   absence of specific global or unique local address definitions, the
   default behavior of routers is to use link-local addresses notably
   for routing protocols.

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