Internet Engineering Task Force                            E. Jankiewicz
Internet-Draft                                   SRI International, Inc.
Obsoletes: 4294 (if approved)                                J. Loughney
Intended status: Informational                                     Nokia
Expires: December 2, 2011                                      T. Narten
                                                         IBM Corporation
                                                            May 31, 2011


                         IPv6 Node Requirements
                  draft-ietf-6man-node-req-bis-11.txt

Abstract

   This document defines requirements for IPv6 nodes.  It is expected
   that IPv6 will be deployed in a wide range of devices and situations.
   Specifying the requirements for IPv6 nodes allows IPv6 to function
   well and interoperate in a large number of situations and
   deployments.

   This document obsoletes RFC4294.

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 December 2, 2011.

Copyright Notice

   Copyright (c) 2011 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



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   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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.


































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Table of Contents

   1.  Requirements Language  . . . . . . . . . . . . . . . . . . . .  5
   2.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
     2.1.  Scope of This Document . . . . . . . . . . . . . . . . . .  6
     2.2.  Description of IPv6 Nodes  . . . . . . . . . . . . . . . .  6
   3.  Abbreviations Used in This Document  . . . . . . . . . . . . .  6
   4.  Sub-IP Layer . . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  IP Layer . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     5.1.  Internet Protocol Version 6 - RFC 2460 . . . . . . . . . .  8
     5.2.  Neighbor Discovery for IPv6 - RFC 4861 . . . . . . . . . .  8
     5.3.  Default Router Preferences and More-Specific Routes -
           RFC 4191 . . . . . . . . . . . . . . . . . . . . . . . . .  9
     5.4.  SEcure Neighbor Discovery (SEND) - RFC 3971  . . . . . . . 10
     5.5.  IPv6 Router Advertisement Flags Option - RFC 5175  . . . . 10
     5.6.  Path MTU Discovery and Packet Size . . . . . . . . . . . . 10
       5.6.1.  Path MTU Discovery - RFC 1981  . . . . . . . . . . . . 10
     5.7.  IPv6 Jumbograms - RFC 2675 . . . . . . . . . . . . . . . . 11
     5.8.  ICMP for the Internet Protocol Version 6 (IPv6) - RFC
           4443 . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.9.  Addressing . . . . . . . . . . . . . . . . . . . . . . . . 11
       5.9.1.  IP Version 6 Addressing Architecture - RFC 4291  . . . 11
       5.9.2.  IPv6 Stateless Address Autoconfiguration - RFC 4862  . 11
       5.9.3.  Privacy Extensions for Address Configuration in
               IPv6 - RFC 4941  . . . . . . . . . . . . . . . . . . . 12
       5.9.4.  Default Address Selection for IPv6 - RFC 3484  . . . . 12
       5.9.5.  Stateful Address Autoconfiguration (DHCPv6) - RFC
               3315 . . . . . . . . . . . . . . . . . . . . . . . . . 13
     5.10. Multicast Listener Discovery (MLD) for IPv6  . . . . . . . 13
   6.  DHCP vs. Router Advertisement Options for Host
       Configuration  . . . . . . . . . . . . . . . . . . . . . . . . 14
   7.  DNS and DHCP . . . . . . . . . . . . . . . . . . . . . . . . . 15
     7.1.  DNS  . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     7.2.  Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
           - RFC 3315 . . . . . . . . . . . . . . . . . . . . . . . . 15
       7.2.1.  Other Configuration Information  . . . . . . . . . . . 15
       7.2.2.  Use of Router Advertisements in Managed
               Environments . . . . . . . . . . . . . . . . . . . . . 15
     7.3.  IPv6 Router Advertisement Options for DNS
           Configuration - RFC 6106 . . . . . . . . . . . . . . . . . 15
   8.  IPv4 Support and Transition  . . . . . . . . . . . . . . . . . 16
     8.1.  Transition Mechanisms  . . . . . . . . . . . . . . . . . . 16
       8.1.1.  Basic Transition Mechanisms for IPv6 Hosts and
               Routers - RFC 4213 . . . . . . . . . . . . . . . . . . 16
   9.  Application Support  . . . . . . . . . . . . . . . . . . . . . 16
     9.1.  Textual Representation of IPv6 Addresses - RFC 5952  . . . 16
     9.2.  Application Program Interfaces (APIs)  . . . . . . . . . . 16
   10. Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . 17



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   11. Security . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     11.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 18
     11.2. Transforms and Algorithms  . . . . . . . . . . . . . . . . 19
   12. Router-Specific Functionality  . . . . . . . . . . . . . . . . 19
     12.1. IPv6 Router Alert Option - RFC 2711  . . . . . . . . . . . 19
     12.2. Neighbor Discovery for IPv6 - RFC 4861 . . . . . . . . . . 19
     12.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 . . 19
   13. Network Management . . . . . . . . . . . . . . . . . . . . . . 20
     13.1. Management Information Base Modules (MIBs) . . . . . . . . 20
       13.1.1. IP Forwarding Table MIB  . . . . . . . . . . . . . . . 20
       13.1.2. Management Information Base for the Internet
               Protocol (IP)  . . . . . . . . . . . . . . . . . . . . 20
   14. Security Considerations  . . . . . . . . . . . . . . . . . . . 20
   15. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 21
   16. Authors and  Acknowledgments . . . . . . . . . . . . . . . . . 21
     16.1. Authors and Acknowledgments (Current Document) . . . . . . 21
     16.2. Authors and Acknowledgments From RFC 4279  . . . . . . . . 21
   17. Appendix: Changes from One ID version to Another . . . . . . . 22
     17.1. Appendix: Changes from -10to -11 . . . . . . . . . . . . . 22
     17.2. Appendix: Changes from -09 to -10  . . . . . . . . . . . . 22
     17.3. Appendix: Changes from -08 to -09  . . . . . . . . . . . . 22
     17.4. Appendix: Changes from -07 to -08  . . . . . . . . . . . . 22
     17.5. Appendix: Changes from -06 to -07  . . . . . . . . . . . . 23
     17.6. Appendix: Changes from -05 to -06  . . . . . . . . . . . . 23
     17.7. Appendix: Changes from -04 to -05  . . . . . . . . . . . . 23
     17.8. Appendix: Changes from -03 to -04  . . . . . . . . . . . . 24
   18. Appendix: Changes from RFC 4294  . . . . . . . . . . . . . . . 24
   19. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
     19.1. Normative References . . . . . . . . . . . . . . . . . . . 25
     19.2. Informative References . . . . . . . . . . . . . . . . . . 28
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31




















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1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].


2.  Introduction

   This document defines common functionality required from both IPv6
   hosts and routers.  Many IPv6 nodes will implement optional or
   additional features, but this document collects and summarizes
   requirements from other published Standards Track documents in one
   place.

   This document tries to avoid discussion of protocol details, and
   references RFCs for this purpose.  This document is intended to be an
   Applicability Statement and provide guidance as to which IPv6
   specifications should be implemented in the general case, and which
   specification may be of interest to specific deployment scenarios.
   This document does not update any individual protocol document RFCs.

   Although the document points to different specifications, it should
   be noted that in many cases, the granularity of a particular
   requirement will be smaller than a single specification, as many
   specifications define multiple, independent pieces, some of which may
   not be mandatory.  In addition, most specifications define both
   client and server behavior in the same specification, while many
   implementations will be focused on only one of those roles.

   This document defines a minimal level of requirement needed for a
   device to provide useful internet service and considers a broad range
   of device types and deployment scenarios.  Because of the wide range
   of deployment scenarios, the minimal requirements specified in this
   document may not be sufficient for all deployment scenarios.  It is
   perfectly reasonable (and indeed expected) for other profiles to
   define additional or stricter requirements appropriate for specific
   usage and deployment environments.  For example, this document does
   not mandate that all clients support DHCP, but some deployment
   scenarios may deem it appropriate to make such a requirement.  For
   example, government agencies in the USA have defined profiles for
   specialized requirements for IPv6 in target environments [DODv6] and
   [USGv6].

   As it is not always possible for an implementer to know the exact
   usage of IPv6 in a node, an overriding requirement for IPv6 nodes is
   that they should adhere to Jon Postel's Robustness Principle:




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   Be conservative in what you do, be liberal in what you accept from
   others [RFC0793].

2.1.  Scope of This Document

   IPv6 covers many specifications.  It is intended that IPv6 will be
   deployed in many different situations and environments.  Therefore,
   it is important to develop the requirements for IPv6 nodes to ensure
   interoperability.

   This document assumes that all IPv6 nodes meet the minimum
   requirements specified here.

2.2.  Description of IPv6 Nodes

   From the Internet Protocol, Version 6 (IPv6) Specification [RFC2460],
   we have the following definitions:

   Description of an IPv6 Node

   - a device that implements IPv6.

   Description of an IPv6 router

   - a node that forwards IPv6 packets not explicitly addressed to
   itself.

   Description of an IPv6 Host

   - any node that is not a router.


3.  Abbreviations Used in This Document

      ATM Asynchronous Transfer Mode
      AH Authentication Header
      DAD Duplicate Address Detection
      ESP Encapsulating Security Payload
      ICMP Internet Control Message Protocol
      IKE Internet Key Exchange
      MIB Management Information Base
      MLD Multicast Listener Discovery
      MTU Maximum Transfer Unit
      NA Neighbor Advertisement







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      NBMA Non-Broadcast Multiple Access
      ND Neighbor Discovery
      NS Neighbor Solicitation
      NUD Neighbor Unreachability Detection
      PPP Point-to-Point Protocol
      PVC Permanent Virtual Circuit
      SVC Switched Virtual Circuit


4.  Sub-IP Layer

   An IPv6 node must include support for one or more IPv6 link-layer
   specifications.  Which link-layer specifications an implementation
   should include will depend upon what link-layers are supported by the
   hardware available on the system.  It is possible for a conformant
   IPv6 node to support IPv6 on some of its interfaces and not on
   others.

   As IPv6 is run over new layer 2 technologies, it is expected that new
   specifications will be issued.  In the following, we list some of the
   link-layers for which an IPv6 specification has been developed.  It
   is provided for information purposes only, and may not be complete.

   -  Transmission of IPv6 Packets over Ethernet Networks [RFC2464]
   -  IPv6 over ATM Networks [RFC2492]
   -  Transmission of IPv6 Packets over Frame Relay Networks
      Specification [RFC2590]
   -  Transmission of IPv6 Packets over IEEE 1394 Networks [RFC3146]
   -  Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP)
      Packets over Fibre Channel [RFC4338]
   -  Transmission of IPv6 Packets over IEEE 802.15.4 Networks [RFC4944]
   -  Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE
      802.16 Networks [RFC5121]
   -  IP version 6 over PPP [RFC5072]

   In addition to traditional physical link-layers, it is also possible
   to tunnel IPv6 over other protocols.  Examples include:

   -  Teredo: Tunneling IPv6 over UDP through Network Address
      Translations (NATs) [RFC4380]
   -  Section 3 of "Basic IPv6 Transition Mechanisms" [RFC4213]


5.  IP Layer







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5.1.  Internet Protocol Version 6 - RFC 2460

   The Internet Protocol Version 6 is specified in [RFC2460].  This
   specification MUST be supported.

   Any unrecognized extension headers or options MUST be processed as
   described in RFC 2460.

   The node MUST follow the packet transmission rules in RFC 2460.

   Nodes MUST always be able to send, receive, and process fragment
   headers.  All conformant IPv6 implementations MUST be capable of
   sending and receiving IPv6 packets; the forwarding functionality MAY
   be supported.  Overlapping fragments MUST be handled as described in
   [RFC5722].

   RFC 2460 specifies extension headers and the processing for these
   headers.

   An IPv6 node MUST be able to process these headers.  An exception is
   Routing Header type 0 (RH0) which was deprecated by [RFC5095] due to
   security concerns, and which MUST be treated as an unrecognized
   routing type.

5.2.  Neighbor Discovery for IPv6 - RFC 4861

   Neighbor Discovery is defined in [RFC4861] and was updated by
   [RFC5942].  Neighbor Discovery SHOULD be supported.  RFC4861 states:

      Unless specified otherwise (in a document that covers operating IP
      over a particular link type) this document applies to all link
      types.  However, because ND uses link-layer multicast for some of
      its services, it is possible that on some link types (e.g., NBMA
      links) alternative protocols or mechanisms to implement those
      services will be specified (in the appropriate document covering
      the operation of IP over a particular link type).  The services
      described in this document that are not directly dependent on
      multicast, such as Redirects, Next-hop determination, Neighbor
      Unreachability Detection, etc., are expected to be provided as
      specified in this document.  The details of how one uses ND on
      NBMA links is an area for further study.

   Some detailed analysis of Neighbor Discovery follows:

   Router Discovery is how hosts locate routers that reside on an
   attached link.  Hosts MUST support Router Discovery functionality.

   Prefix Discovery is how hosts discover the set of address prefixes



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   that define which destinations are on-link for an attached link.
   Hosts MUST support Prefix discovery.

   Hosts MUST also implement Neighbor Unreachability Detection (NUD) for
   all paths between hosts and neighboring nodes.  NUD is not required
   for paths between routers.  However, all nodes MUST respond to
   unicast Neighbor Solicitation (NS) messages.

   Hosts MUST support the sending of Router Solicitations and the
   receiving of Router Advertisements.  The ability to understand
   individual Router Advertisement options is dependent on supporting
   the functionality making use of the particular option.

   All nodes MUST support the Sending and Receiving of Neighbor
   Solicitation (NS) and Neighbor Advertisement (NA) messages.  NS and
   NA messages are required for Duplicate Address Detection (DAD).

   Hosts SHOULD support the processing of Redirect functionality.
   Routers MUST support the sending of Redirects, though not necessarily
   for every individual packet (e.g., due to rate limiting).  Redirects
   are only useful on networks supporting hosts.  In core networks
   dominated by routers, redirects are typically disabled.  The sending
   of redirects SHOULD be disabled by default on backbone routers.  They
   MAY be enabled by default on routers intended to support hosts on
   edge networks.

   "IPv6 Host-to-Router Load Sharing" [RFC4311] includes additional
   recommendations on how to select from a set of available routers.
   RFC 4311 SHOULD be supported.

5.3.  Default Router Preferences and More-Specific Routes - RFC 4191

   "Default Router Preferences and More-Specific Routes" [RFC4191]
   provides support for nodes attached to multiple (different) networks
   each providing routers that advertise themselves as default routers
   via Router Advertisements.  In some scenarios, one router may provide
   connectivity to destinations the other router does not and choosing
   the "wrong" default router can result in reachability failures.  In
   such cases, RFC4191 can help.

   Small Office/Home Office (SOHO) deployments supported by routers
   adhering to [RFC6204], use [RFC4191] to advertise routes to certain
   local destinations.  Consequently, nodes that will be deployed in
   SOHO environments SHOULD implement [RFC4191].







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5.4.  SEcure Neighbor Discovery (SEND) - RFC 3971

   SEND [RFC3971] and Cryptographically Generated Address (CGA)
   [RFC3972] provide a way to secure the message exchanges of Neighbor
   Discovery.  SEND is a new technology, in that it has no IPv4
   counterpart but it has significant potential to address certain
   classes of spoofing attacks.  While there have been some
   implementations of SEND, there has been only limited deployment
   experience to date in using the technology.  In addition, the IETF
   working group Cga & Send maIntenance (csi) is currently working on
   additional extensions intended to make SEND more attractive for
   deployment.

   At this time, SEND is considered optional and IPv6 nodes MAY provide
   SEND functionality.

5.5.  IPv6 Router Advertisement Flags Option - RFC 5175

   Router Advertisements include an 8-bit field of single-bit Router
   Advertisement flags.  The Router Advertisement Flags Option extends
   the number of available flag bits by 48 bits.  At the time of this
   writing, 6 of the original 8 bit flags have been assigned, while 2
   remain available for future assignment.  No flags have been defined
   that make use of the new option, and thus strictly speaking, there is
   no requirement to implement the option today.  However,
   implementations that are able to pass unrecognized options to a
   higher level entity that may be able to understand them (e.g., a
   user-level process using a "raw socket" facility), MAY take steps to
   handle the option in anticipation of a future usage.

5.6.  Path MTU Discovery and Packet Size

5.6.1.  Path MTU Discovery - RFC 1981

   "Path MTU Discovery" [RFC1981] SHOULD be supported.  From [RFC2460]:

      It is strongly recommended that IPv6 nodes implement Path MTU
      Discovery [RFC1981], in order to discover and take advantage of
      path MTUs greater than 1280 octets.  However, a minimal IPv6
      implementation (e.g., in a boot ROM) may simply restrict itself to
      sending packets no larger than 1280 octets, and omit
      implementation of Path MTU Discovery.

   The rules in [RFC2460] and [RFC5722] MUST be followed for packet
   fragmentation and reassembly.

   One operational issue with Path MTU discovery occurs when firewalls
   block ICMP Packet Too Big messages.  Path MTU discovery relies on



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   such messages to determine what size messages can be successfully
   sent.  Packetization Layer Path MTU Discovery [RFC4821] avoids having
   a dependency on Packet Too Big messages.

5.7.  IPv6 Jumbograms - RFC 2675

   IPv6 Jumbograms [RFC2675] are an optional extension that allow the
   sending of IP datagrams larger than 65.535 bytes.  IPv6 Jumbograms
   make use of IPv6 hop-by-hop options and are only suitable on paths in
   which every hop and link are capable of supporting Jumbograms (e.g.,
   within a campus or datacenter).  To date, few implementations exist
   and there is essentially no reported experience from usage.
   Consequently, IPv6 Jumbograms [RFC2675] remain optional at this time.

5.8.  ICMP for the Internet Protocol Version 6 (IPv6) - RFC 4443

   ICMPv6 [RFC4443] MUST be supported.  "Extended ICMP to Support Multi-
   Part Messages" [RFC4884] MAY be supported.

5.9.  Addressing

5.9.1.  IP Version 6 Addressing Architecture - RFC 4291

   The IPv6 Addressing Architecture [RFC4291] MUST be supported.

5.9.2.  IPv6 Stateless Address Autoconfiguration - RFC 4862

   Hosts MUST support IPv6 Stateless Address Autoconfiguration as
   defined in [RFC4862].  Configuration of static address(es) may be
   supported as well.

   Nodes that are routers MUST be able to generate link local addresses
   as described in RFC 4862 [RFC4862].

   From 4862:

      The autoconfiguration process specified in this document applies
      only to hosts and not routers.  Since host autoconfiguration uses
      information advertised by routers, routers will need to be
      configured by some other means.  However, it is expected that
      routers will generate link-local addresses using the mechanism
      described in this document.  In addition, routers are expected to
      successfully pass the Duplicate Address Detection procedure
      described in this document on all addresses prior to assigning
      them to an interface.

   All nodes MUST implement Duplicate Address Detection.  Quoting from
   Section 5.4 of RFC 4862:



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      Duplicate Address Detection MUST be performed on all unicast
      addresses prior to assigning them to an interface, regardless of
      whether they are obtained through stateless autoconfiguration,
      DHCPv6, or manual configuration, with the following [exceptions
      noted therein].

   "Optimistic Duplicate Address Detection (DAD) for IPv6" [RFC4429]
   specifies a mechanism to reduce delays associated with generating
   addresses via stateless address autoconfiguration [RFC4862].  RFC
   4429 was developed in conjunction with Mobile IPv6 in order to reduce
   the time needed to acquire and configure addresses as devices quickly
   move from one network to another, and it is desirable to minimize
   transition delays.  For general purpose devices, RFC 4429 remains
   optional at this time.

5.9.3.  Privacy Extensions for Address Configuration in IPv6 - RFC 4941

   Privacy Extensions for Stateless Address Autoconfiguration [RFC4941]
   addresses a specific problem involving a client device whose user is
   concerned about its activity or location being tracked.  The problem
   arises both for a static client and for one that regularly changes
   its point of attachment to the Internet.  When using Stateless
   Address Autoconfiguration [RFC4862], the Interface Identifier portion
   of formed addresses stays constant and is globally unique.  Thus,
   although a node's global IPv6 address will change if it changes its
   point of attachment, the Interface Identifier portion of those
   addresses remain the same, making it possible for servers to track
   the location of an individual device as it moves around, or its
   pattern of activity if it remains in one place.  This may raise
   privacy concerns as described in [RFC4862].

   In such situations, RFC4941 SHOULD be implemented.  In other cases,
   such as with dedicated servers in a data center, RFC4941 provides
   limited or no benefit.

   Implementers of "RFC4941 should be aware that certain addresses are
   reserved and should not be chosen for use as temporary addresses.
   Consult "Reserved IPv6 Interface Identifiers" [RFC5453] for more
   details.

5.9.4.  Default Address Selection for IPv6 - RFC 3484

   The rules specified in the Default Address Selection for IPv6
   [RFC3484] document MUST be implemented.  IPv6 nodes will need to deal
   with multiple addresses configured simultaneously.






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5.9.5.  Stateful Address Autoconfiguration (DHCPv6) - RFC 3315

   DHCPv6 [RFC3315] can be used to obtain and configure addresses.  In
   general, a network may provide for the configuration of addresses
   through Router Advertisements, DHCPv6 or both.  There will be a wide
   range of IPv6 deployment models and differences in address assignment
   requirements, some of which may require DHCPv6 for address
   assignment.  Consequently all hosts SHOULD implement address
   configuration via DHCPv6.

   In the absence of a router, IPv6 nodes using DHCP for address
   assignment MAY initiate DHCP to obtain IPv6 addresses and other
   configuration information, as described in Section 5.5.2 of
   [RFC4862].

5.10.  Multicast Listener Discovery (MLD) for IPv6

   Nodes that need to join multicast groups MUST support MLDv1
   [RFC2710].  MLDv1 is needed by any node that is expected to receive
   and process multicast traffic.  Note that Neighbor Discovery (as used
   on most link types -- see Section 5.2) depends on multicast and
   requires that nodes join Solicited Node multicast addresses.

   MLDv2 [RFC3810] extends the functionality of MLDv1 by supporting
   Source-Specific Multicast.  The original MLDv2 protocol [RFC3810]
   supporting Source-Specific Multicast [RFC4607] supports two types of
   "filter modes".  Using an INCLUDE filter, a node indicates a
   multicast group along with a list of senders for that group it wishes
   to receive traffic from.  Using an EXCLUDE filter, a node indicates a
   multicast group along with a list of senders it wishes to exclude
   receiving traffic from.  In practice, operations to block source(s)
   using EXCLUDE mode are rarely used, but add considerable
   implementation complexity to MLDv2.  Lightweight MLDv2 [RFC5790] is a
   simplified subset of the original MLDv2 specification that omits
   EXCLUDE filter mode to specify undesired source(s).

   Nodes SHOULD implement either MLDv2 [RFC3810] or Lightweight MLDv2
   [RFC5790].  Specifically, nodes supporting applications using Source-
   Specific Multicast that expect to take advantage of MLDv2's EXCLUDE
   functionality [RFC3810] MUST support MLDv2 as defined in [RFC3810],
   [RFC4604] and [RFC4607].  Nodes supporting applications that expect
   to only take advantage of MLDv2's INCLUDE functionality as well as
   Any-Source Multicast will find it sufficient to support MLDv2 as
   defined in [RFC5790].

   If a node only supports applications that use Any-Source Multicast
   (i.e, they do not use source-specific multicast), implementing MLDv1
   [RFC2710] is sufficient.  In all cases, however, nodes are strongly



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   encouraged to implement MLDv2 or Lightweight MLDv2 rather than MLDv1,
   as the presence of a single MLDv1 participant on a link requires that
   all other nodes on the link operate in version 1 compatibility mode.

   When MLDv1 is used, the rules in the Source Address Selection for the
   Multicast Listener Discovery (MLD) Protocol [RFC3590] MUST be
   followed.


6.  DHCP vs. Router Advertisement Options for Host Configuration

   In IPv6, there are two main protocol mechanisms for propagating
   configuration information to hosts: Router Advertisements and DHCP.
   Historically, RA options have been restricted to those deemed
   essential for basic network functioning and for which all nodes are
   configured with exactly the same information.  Examples include the
   Prefix Information Options, the MTU option, etc.  On the other hand,
   DHCP has generally been preferred for configuration of more general
   parameters and for parameters that may be client-specific.  That
   said, identifying the exact line on whether a particular option
   should be configured via DHCP vs. an RA option has not always been
   easy.  Generally speaking, however, there has been a desire to define
   only one mechanism for configuring a given option, rather than
   defining multiple (different) ways of configuring the same
   information.

   One issue with having multiple ways of configuring the same
   information is that if a host chooses one mechanism, but the network
   operator chooses a different mechanism, interoperability suffers.
   For "closed" environments, where the network operator has significant
   influence over what devices connect to the network and thus what
   configuration mechanisms they support, the operator may be able to
   ensure that a particular mechanism is supported by all connected
   hosts.  In more open environments, however, where arbitrary devices
   may connect (e.g., a WIFI hotspot), problems can arise.  To maximize
   interoperability in such environments hosts would need to implement
   multiple configuration mechanisms to ensure interoperability.

   Originally in IPv6, configuring information about DNS servers was
   performed exclusively via DHCP.  In 2007, an RA option was defined,
   but was published as Experimental [RFC5006].  In 2010, "IPv6 Router
   Advertisement Options for DNS Configuration" [RFC6106] was published
   as a Standards Track Document.  Consequently, DNS configuration
   information can now be learned either through DHCP or through RAs.
   Hosts will need to decide which mechanism (or whether both) should be
   implemented.  Specific guidance regarding DNS server discovery is
   discussed in Section 7.




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7.  DNS and DHCP

7.1.  DNS

   DNS is described in [RFC1034], [RFC1035], [RFC3363], and [RFC3596].
   Not all nodes will need to resolve names; those that will never need
   to resolve DNS names do not need to implement resolver functionality.
   However, the ability to resolve names is a basic infrastructure
   capability that applications rely on and most nodes will need to
   provide support.  All nodes SHOULD implement stub-resolver [RFC1034]
   functionality, as in RFC 1034, Section 5.3.1, with support for:

      - AAAA type Resource Records [RFC3596];
      - reverse addressing in ip6.arpa using PTR records [RFC3596];
      - EDNS0 [RFC2671] to allow for DNS packet sizes larger than 512
      octets.

   Those nodes are RECOMMENDED to support DNS security extensions
   [RFC4033], [RFC4034], and [RFC4035].

   Those nodes are NOT RECOMMENDED to support the experimental A6
   Resource Records [RFC3363].

7.2.  Dynamic Host Configuration Protocol for IPv6 (DHCPv6) - RFC 3315

7.2.1.  Other Configuration Information

   IPv6 nodes use DHCP [RFC3315] to obtain address configuration
   information (See Section 5.8.5) and to obtain additional (non-
   address) configuration.  If a host implementation supports
   applications or other protocols that require configuration that is
   only available via DHCP, hosts SHOULD implement DHCP.  For
   specialized devices on which no such configuration need is present,
   DHCP may not be necessary.

   An IPv6 node can use the subset of DHCP (described in [RFC3736]) to
   obtain other configuration information.

7.2.2.  Use of Router Advertisements in Managed Environments

   Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
   are expected to determine their default router information and on-
   link prefix information from received Router Advertisements.

7.3.  IPv6 Router Advertisement Options for DNS Configuration - RFC 6106

   Router Advertisements have historically limited options to those that
   are critical to basic IPv6 functioning.  Originally, DNS



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   configuration was not included as an RA option and DHCP was the
   recommended way to obtain DNS configuration information.  Over time,
   the thinking surrounding such an option has evolved.  It is now
   generally recognized that few nodes can function adequately without
   having access to a working DNS resolver.  RFC 5006 was published as
   an experimental document in 2007, and recently, a revised version was
   placed on the Standards Track [RFC6106].

   Implementations SHOULD implement the DNS RA option [RFC6106].


8.  IPv4 Support and Transition

   IPv6 nodes MAY support IPv4.

8.1.  Transition Mechanisms

8.1.1.  Basic Transition Mechanisms for IPv6 Hosts and Routers - RFC
        4213

   If an IPv6 node implements dual stack and tunneling, then [RFC4213]
   MUST be supported.


9.  Application Support

9.1.  Textual Representation of IPv6 Addresses - RFC 5952

   Software that allows users and operators to input IPv6 addresses in
   text form SHOULD support "A Recommendation for IPv6 Address Text
   Representation" [RFC5952].

9.2.  Application Program Interfaces (APIs)

   There are a number of IPv6-related APIs.  This document does not
   mandate the use of any, because the choice of API does not directly
   relate to on-the-wire behavior of protocols.  Implementers, however,
   would be advised to consider providing a common API, or reviewing
   existing APIs for the type of functionality they provide to
   applications.

   "Basic Socket Interface Extensions for IPv6" [RFC3493] provides IPv6
   functionality used by typical applications.  Implementers should note
   that RFC3493 has been picked up and further standardized by POSIX
   [POSIX].

   "Advanced Sockets Application Program Interface (API) for IPv6"
   [RFC3542] provides access to advanced IPv6 features needed by



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   diagnostic and other more specialized applications.

   "IPv6 Socket API for Source Address Selection" [RFC5014] provides
   facilities that allow an application to override the default Source
   Address Selection rules of [RFC3484].

   "Socket Interface Extensions for Multicast Source Filters" [RFC3678]
   provides support for expressing source filters on multicast group
   memberships.

   "Extension to Sockets API for Mobile IPv6" [RFC4584] provides
   application support for accessing and enabling Mobile IPv6 features.
   [RFC3775]


10.  Mobility

   Mobile IPv6 [RFC3775] and associated specifications [RFC3776]
   [RFC4877] allow a node to change its point of attachment within the
   Internet, while maintaining (and using) a permanent address.  All
   communication using the permanent address continues to proceed as
   expected even as the node moves around.  The definition of Mobile IP
   includes requirements for the following types of nodes:

      - mobile nodes
      - correspondent nodes with support for route optimization
      - home agents
      - all IPv6 routers

   At the present time, Mobile IP has seen only limited implementation
   and no significant deployment, partly because it originally assumed
   an IPv6-only environment, rather than a mixed IPv4/IPv6 Internet.
   Recently, additional work has been done to support mobility in mixed-
   mode IPv4 and IPv6 networks[RFC5555].

   More usage and deployment experience is needed with mobility before
   any specific approach can be recommended for broad implementation in
   all hosts and routers.  Consequently, [RFC3775], [RFC5555], and
   associated standards such as [RFC4877] are considered a MAY at this
   time.


11.  Security

   This section describes the specification for security for IPv6 nodes.

   Achieving security in practice is a complex undertaking.  Operational
   procedures, protocols, key distribution mechanisms, certificate



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   management approaches, etc. are all components that impact the level
   of security actually achieved in practice.  More importantly,
   deficiencies or a poor fit in any one individual component can
   significantly reduce the overall effectiveness of a particular
   security approach.

   IPsec provides channel security at the Internet layer, making it
   possible to provide secure communication for all (or a subset of)
   communication flows at the IP layer between pairs of internet nodes.
   IPsec provides sufficient flexibility and granularity that individual
   TCP connections can (selectively) be protected, etc.

   Although IPsec can be used with manual keying in some cases, such
   usage has limited applicability and is not recommended.

   A range of security technologies and approaches proliferate today
   (e.g., IPsec, TLS, SSH, etc.)  No one approach has emerged as an
   ideal technology for all needs and environments.  Moreover, IPsec is
   not viewed as the ideal security technology in all cases and is
   unlikely to displace the others.

   Previously, IPv6 mandated implementation of IPsec and recommended the
   key management approach of IKE.  This document updates that
   recommendation by making support of the IP Security Architecture [RFC
   4301] a SHOULD for all IPv6 nodes.  Note that the IPsec Architecture
   requires (e.g., Sec. 4.5 of RFC 4301) the implementation of both
   manual and automatic key management.  Currently the default automated
   key management protocol to implement is IKEv2 [RFC5996].

   This document recognizes that there exists a range of device types
   and environments where other approaches to security than IPsec can be
   justified.  For example, special-purpose devices may support only a
   very limited number or type of applications and an application-
   specific security approach may be sufficient for limited management
   or configuration capabilities.  Alternatively, some devices my run on
   extremely constrained hardware (e.g., sensors) where the full IP
   Security Architecture is not justified.

11.1.  Requirements

   "Security Architecture for the Internet Protocol" [RFC4301] SHOULD be
   supported by all IPv6 nodes.  Note that the IPsec Architecture
   requires (e.g., Sec. 4.5 of RFC 4301) the implementation of both
   manual and automatic key management.  Currently the default automated
   key management protocol to implement is IKEv2.  As required in
   [RFC4301], IPv6 nodes implementing the IPsec Architecture MUST
   implement ESP [RFC4303] and MAY implement AH [RFC4302].




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11.2.  Transforms and Algorithms

   The current set of mandatory-to-implement algorithms for the IP
   Security Architecture are defined in 'Cryptographic Algorithm
   Implementation Requirements For ESP and AH' [RFC4835].  IPv6 nodes
   implementing the IP Security Architecture MUST conform to the
   requirements in [RFC4835].  Preferred cryptographic algorithms often
   change more frequently than security protocols.  Therefore
   implementations MUST allow for migration to new algorithms, as
   RFC4835 is replaced or updated in the future.

   The current set of mandatory-to-implement algorithms for IKEv2 are
   defined in 'Cryptographic Algorithms for Use in the Internet Key
   Exchange Version 2 (IKEv2)' [RFC4307].  IPv6 nodes implementing IKEv2
   MUST conform to the requirements in [RFC4307] and/or any future
   updates or replacements to [RFC4307].


12.  Router-Specific Functionality

   This section defines general host considerations for IPv6 nodes that
   act as routers.  Currently, this section does not discuss routing-
   specific requirements.

12.1.  IPv6 Router Alert Option - RFC 2711

   The IPv6 Router Alert Option [RFC2711] is an optional IPv6 Hop-by-Hop
   Header that is used in conjunction with some protocols (e.g., RSVP
   [RFC2205] or MLD [RFC2710]).  The Router Alert option will need to be
   implemented whenever protocols that mandate its usage (e.g., MLD) are
   implemented.  See Section 5.9.

12.2.  Neighbor Discovery for IPv6 - RFC 4861

   Sending Router Advertisements and processing Router Solicitation MUST
   be supported.

   Section 7 of RFC 3775 includes some mobility-specific extensions to
   Neighbor Discovery.  Routers SHOULD implement Sections 7.3 and 7.5,
   even if they do not implement Home Agent functionality.

12.3.  Stateful Address Autoconfiguration (DHCPv6) - RFC 3315

   A single DHCP server ([RFC3315] or [RFC4862]) can provide
   configuration information to devices directly attached to a shared
   link, as well as to devices located elsewhere within a site.
   Communication between a client and a DHCP server located on different
   links requires the use of DHCP relay agents on routers.



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   In simple deployments, consisting of a single router and either a
   single LAN, or multiple LANs attached to the single router, together
   with a WAN connection, a DHCP server embedded within the router is
   one common deployment scenario (e.g., [RFC6204]).  However, there is
   no need for relay agents in such scenarios.

   In more complex deployment scenarios, such as within enterprise or
   service provider networks, the use of DHCP requires some level of
   configuration, in order to configure relay agents, DHCP servers, etc.
   In such environments, the DHCP server might even be run on a
   traditional server, rather than as part of a router.

   Because of the wide range of deployment scenarios, support for DHCP
   server functionality on routers is optional.  However, routers
   targeted for deployment within more complex scenarios (as described
   above) SHOULD support relay agent functionality.  Note that "Basic
   Requirements for IPv6 Customer Edge Routers" [RFC6204] requires
   implementation of a DHCPv6 server function in IPv6 CE routers.


13.  Network Management

   Network Management MAY be supported by IPv6 nodes.  However, for IPv6
   nodes that are embedded devices, network management may be the only
   possible way of controlling these nodes.

13.1.  Management Information Base Modules (MIBs)

   The following two MIB modules SHOULD be supported by nodes that
   support an SNMP agent.

13.1.1.  IP Forwarding Table MIB

   IP Forwarding Table MIB [RFC4292] SHOULD be supported by nodes that
   support an SNMP agent.

13.1.2.  Management Information Base for the Internet Protocol (IP)

   IP MIB [RFC4293] SHOULD be supported by nodes that support an SNMP
   agent.


14.  Security Considerations

   This document does not directly affect the security of the Internet,
   beyond the security considerations associated with the individual
   protocols.




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   Security is also discussed in Section 10 above.


15.  IANA Considerations

   This document has no requests for IANA.


16.  Authors and  Acknowledgments

16.1.  Authors and Acknowledgments (Current Document)

   For this version of the IPv6 Node Requirements document, the authors
   would like to thank Hitoshi Asaeda, Brian Carpenter, Tim Chown, Ralph
   Droms, Sheila Frankel, Sam Hartman, Bob Hinden, Paul Hoffman, Pekka
   Savola, Yaron Sheffer and Dave Thaler for their comments.

16.2.  Authors and Acknowledgments From RFC 4279

   The original version of this document (RFC 4279) was written by the
   IPv6 Node Requirements design team:

      Jari Arkko
      jari.arkko@ericsson.com
      Marc Blanchet
      marc.blanchet@viagenie.qc.ca
      Samita Chakrabarti
      samita.chakrabarti@eng.sun.com
      Alain Durand
      alain.durand@sun.com
      Gerard Gastaud
      gerard.gastaud@alcatel.fr
      Jun-ichiro itojun Hagino
      itojun@iijlab.net
      Atsushi Inoue
      inoue@isl.rdc.toshiba.co.jp
      Masahiro Ishiyama
      masahiro@isl.rdc.toshiba.co.jp
      John Loughney
      john.loughney@nokia.com
      Rajiv Raghunarayan
      raraghun@cisco.com
      Shoichi Sakane
      shouichi.sakane@jp.yokogawa.com







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      Dave Thaler
      dthaler@windows.microsoft.com
      Juha Wiljakka
      juha.wiljakka@Nokia.com

   The authors would like to thank Ran Atkinson, Jim Bound, Brian
   Carpenter, Ralph Droms, Christian Huitema, Adam Machalek, Thomas
   Narten, Juha Ollila, and Pekka Savola for their comments.  Thanks to
   Mark Andrews for comments and corrections on DNS text.  Thanks to
   Alfred Hoenes for tracking the updates to various RFCs.


17.  Appendix: Changes from One ID version to Another

   RFC Editor: Please remove this section upon publication.

17.1.  Appendix: Changes from -10to -11

   1.  Editorial cleanups.
   2.  Added section on DHCPv6 for servers.  SHOULD implement relay
       agent functionality, MAY implement servers.

17.2.  Appendix: Changes from -09 to -10

   1.  With changes in requirements for IPsec and Routing Headers,
       clarified language regarding processing of unknown options, and
       removed paragraph lising which extension headers were required to
       be implemented.
   2.  Removed "RFC4292-bis" from title.
   3.  Expanded the text on Jumbograms.
   4.  Changed recommendation of DHCPv6 from MAY to SHOULD.
   5.  Expanded the text on RFC4191, and changed recommendation from MAY
       to SHOULD.

17.3.  Appendix: Changes from -08 to -09

   1.  Updated MLD section to include reference to Lightweight MLD
       [RFC5790]

17.4.  Appendix: Changes from -07 to -08

   1.  Dropped reference to "Transmission of IPv6 over IPv4 Domains
       without Explicit Tunnels" [RFC2429] in favor of a reference to
       tunneling via Basic IPv6 Transition Mechanisms (RFC4313).
   2.  Added reference to "Default Router Preferences and More-Specific
       Routes" [RFC4191] as a MAY.





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   3.  Added reference to "Optimistic Duplicate Address Detection (DAD)
       for IPv6" (RFC4429).
   4.  Added reference to RFC4941 "Reserved IPv6 Interface Identifiers"
   5.  Added Section on APIs.  References are FYI, and none are
       required.
   6.  Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311]
       SHOULD be implemented
   7.  Added reference to RFC5722 (Overlapping Fragments), made it a
       MUST to implement.
   8.  Made "A Recommendation for IPv6 Address Text Representation"
       [RFC5952] a SHOULD.

17.5.  Appendix: Changes from -06 to -07

   1.  Added recommendation that routers implement Section 7.3 and 7.5
       of RFC 3775.
   2.  "IPv6 Router Advertisement Options for DNS Configuration" (RFC
       6106) has been published.
   3.  Further clarifications to the MLD recommendation.
   4.  "Extended ICMP to Support Multi- Part Messages" [RFC4884] added
       as a MAY.
   5.  Added pointer to subnet clarification document (RFC 5942).
   6.  Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311]
       SHOULD be implemented
   7.  Added reference to RFC5722 (Overlapping Fragments), made it a
       MUST to implement.
   8.  Made "A Recommendation for IPv6 Address Text Representation"
       [RFC5952] a SHOULD.

17.6.  Appendix: Changes from -05 to -06

   1.  Completely revised IPsec/IKEv2 section.  Text has been discussed
       by 6man and saag.
   2.  Added text to introduction clarifying that this document applies
       to general nodes and that other profiles may be more specific in
       their requirements
   3.  Editorial cleanups in Neighbor Discovery section in particular.
       Text made more crisp.
   4.  Moved some of the DHCP text around.  Moved stateful address
       discussion to Section 5.8.5.
   5.  Added additional nuance to the redirect requirements w.r.t.
       default configuration setting.

17.7.  Appendix: Changes from -04 to -05

   1.  Cleaned up IPsec section, but key questions (MUST vs. SHOULD)
       still open.




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   2.  Added background section on DHCP vs. RA options.
   3.  Added SHOULD recommendation for DNS configuration vi RAs
       (RFC5006bis).
   4.  Cleaned up DHCP section, as it was referring to the M&O bits.
   5.  Cleaned up the Security Considerations Section.

17.8.  Appendix: Changes from -03 to -04

   1.  Updated the Introduction to indicate document is an applicability
       statement
   2.  Updated the section on Mobility protocols
   3.  Changed Sub-IP Layer Section to just list relevant RFCs, and
       added some more RFCs.
   4.  Added Section on SEND (make it a MAY)
   5.  Redid Section on Privacy Extensions (RFC4941) to add more nuance
       to recommendation
   6.  Redid section on Mobility, and added additional RFCs.


18.  Appendix: Changes from RFC 4294

   1.   There have been many editorial clarifications as well as
        significant additions and updates.  While this section
        highlights some of the changes, readers should not rely on this
        section for a comprehensive list of all changes.
   2.   Updated the Introduction to indicate document is an
        applicability statement and that this document is aimed at
        general nodes.
   3.   Significantly updated the section on Mobility protocols, adding
        references and downgrading previous SHOULDs to MAY.
   4.   Changed Sub-IP Layer Section to just list relevant RFCs, and
        added some more RFCs.
   5.   Added Section on SEND (it is a MAY)
   6.   Revised Section on Privacy Extensions (RFC4941) to add more
        nuance to recommendation.
   7.   Completely revised IPsec/IKEv2 Section, downgrading overall
        recommendation to a SHOULD.
   8.   Upgraded recommendation of DHCPv6 to SHOULD.
   9.   Added background section on DHCP vs RA options, added SHOULD
        recommendation sfor DNS configuration via RAs (RFC 6106),
        cleaned up DHCP recommendations
   10.  Added recommendation that routers implement Section 7.3 and 7.5
        of RFC 3775.
   11.  Added pointer to subnet clarification document (RFC 5942).
   12.  Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311]
        SHOULD be implemented





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   13.  Added reference to RFC5722 (Overlapping Fragments), made it a
        MUST to implement.
   14.  Made "A Recommendation for IPv6 Address Text Representation"
        [RFC5952] a SHOULD.
   15.  Removed mention of "DNAME" from the discussion about RFC-3363.
   16.  Numerous updates to reflect newer versions of IPv6 documents,
        including 4443, 4291, 3596, 4213.
   17.  Removed discussion of "Managed" and "Other" flags in RAs.  There
        is no consensus at present on how to process these flags and
        discussion of their semantics was removed in the most recent
        update of Stateless Address Autoconfiguration (RFC 4862).
   18.  Added many more references to optional IPv6 documents.
   19.  Made "A Recommendation for IPv6 Address Text Representation"
        [RFC5952] a SHOULD.
   20.  Added reference to RFC5722 (Overlapping Fragments), made it a
        MUST to implement.
   21.  Updated MLD section to include reference to Lightweight MLD
        [RFC5790]
   22.  Added SHOULD recommendation for "Default Router Preferences and
        More-Specific Routes" [RFC4191].


19.  References

19.1.  Normative References

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, November 1987.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, November 1987.

   [RFC1981]  McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
              for IP version 6", RFC 1981, August 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC2671]  Vixie, P., "Extension Mechanisms for DNS (EDNS0)",
              RFC 2671, August 1999.

   [RFC2710]  Deering, S., Fenner, W., and B. Haberman, "Multicast
              Listener Discovery (MLD) for IPv6", RFC 2710,
              October 1999.




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   [RFC2711]  Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
              RFC 2711, October 1999.

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC3590]  Haberman, B., "Source Address Selection for the Multicast
              Listener Discovery (MLD) Protocol", RFC 3590,
              September 2003.

   [RFC3596]  Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
              "DNS Extensions to Support IP Version 6", RFC 3596,
              October 2003.

   [RFC3736]  Droms, R., "Stateless Dynamic Host Configuration Protocol
              (DHCP) Service for IPv6", RFC 3736, April 2004.

   [RFC3810]  Vida, R. and L. Costa, "Multicast Listener Discovery
              Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.

   [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "DNS Security Introduction and Requirements",
              RFC 4033, March 2005.

   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              RFC 4034, March 2005.

   [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Protocol Modifications for the DNS Security
              Extensions", RFC 4035, March 2005.

   [RFC4213]  Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
              for IPv6 Hosts and Routers", RFC 4213, October 2005.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC4292]  Haberman, B., "IP Forwarding Table MIB", RFC 4292,
              April 2006.

   [RFC4293]  Routhier, S., "Management Information Base for the
              Internet Protocol (IP)", RFC 4293, April 2006.




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   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, December 2005.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, December 2005.

   [RFC4307]  Schiller, J., "Cryptographic Algorithms for Use in the
              Internet Key Exchange Version 2 (IKEv2)", RFC 4307,
              December 2005.

   [RFC4311]  Hinden, R. and D. Thaler, "IPv6 Host-to-Router Load
              Sharing", RFC 4311, November 2005.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, "Internet Control
              Message Protocol (ICMPv6) for the Internet Protocol
              Version 6 (IPv6) Specification", RFC 4443, March 2006.

   [RFC4604]  Holbrook, H., Cain, B., and B. Haberman, "Using Internet
              Group Management Protocol Version 3 (IGMPv3) and Multicast
              Listener Discovery Protocol Version 2 (MLDv2) for Source-
              Specific Multicast", RFC 4604, August 2006.

   [RFC4607]  Holbrook, H. and B. Cain, "Source-Specific Multicast for
              IP", RFC 4607, August 2006.

   [RFC4835]  Manral, V., "Cryptographic Algorithm Implementation
              Requirements for Encapsulating Security Payload (ESP) and
              Authentication Header (AH)", RFC 4835, April 2007.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, September 2007.

   [RFC5095]  Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
              of Type 0 Routing Headers in IPv6", RFC 5095,
              December 2007.

   [RFC5453]  Krishnan, S., "Reserved IPv6 Interface Identifiers",
              RFC 5453, February 2009.

   [RFC5722]  Krishnan, S., "Handling of Overlapping IPv6 Fragments",



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              RFC 5722, December 2009.

   [RFC5790]  Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet
              Group Management Protocol Version 3 (IGMPv3) and Multicast
              Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790,
              February 2010.

   [RFC5942]  Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet
              Model: The Relationship between Links and Subnet
              Prefixes", RFC 5942, July 2010.

   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", RFC 5952, August 2010.

   [RFC5996]  Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
              "Internet Key Exchange Protocol Version 2 (IKEv2)",
              RFC 5996, September 2010.

   [RFC6106]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
              "IPv6 Router Advertisement Options for DNS Configuration",
              RFC 6106, November 2010.

   [RFC6204]  Singh, H., Beebee, W., Donley, C., Stark, B., and O.
              Troan, "Basic Requirements for IPv6 Customer Edge
              Routers", RFC 6204, April 2011.

19.2.  Informative References

   [DODv6]    DISR IPv6 Standards Technical Working Group, "DoD IPv6
              Standard Profiles For IPv6 Capable Products Version 5.0",
              July 2010,
              <http://jitc.fhu.disa.mil/apl/ipv6/pdf/disr_ipv6_50.pdf>.

   [POSIX]    IEEE, "IEEE Std. 1003.1-2001 Standard for Information
              Technology -- Portable Operating System Interface (POSIX),
              ISO/IEC 9945:2002", December 2001,
              <http://www.opengroup.org/austin>.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, September 1981.

   [RFC2205]  Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997.

   [RFC2429]  Bormann, C., Cline, L., Deisher, G., Gardos, T., Maciocco,
              C., Newell, D., Ott, J., Sullivan, G., Wenger, S., and C.
              Zhu, "RTP Payload Format for the 1998 Version of ITU-T



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              Rec. H.263 Video (H.263+)", RFC 2429, October 1998.

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, December 1998.

   [RFC2492]  Armitage, G., Schulter, P., and M. Jork, "IPv6 over ATM
              Networks", RFC 2492, January 1999.

   [RFC2590]  Conta, A., Malis, A., and M. Mueller, "Transmission of
              IPv6 Packets over Frame Relay Networks Specification",
              RFC 2590, May 1999.

   [RFC2675]  Borman, D., Deering, S., and R. Hinden, "IPv6 Jumbograms",
              RFC 2675, August 1999.

   [RFC3146]  Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets
              over IEEE 1394 Networks", RFC 3146, October 2001.

   [RFC3363]  Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
              Hain, "Representing Internet Protocol version 6 (IPv6)
              Addresses in the Domain Name System (DNS)", RFC 3363,
              August 2002.

   [RFC3493]  Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
              Stevens, "Basic Socket Interface Extensions for IPv6",
              RFC 3493, February 2003.

   [RFC3542]  Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
              "Advanced Sockets Application Program Interface (API) for
              IPv6", RFC 3542, May 2003.

   [RFC3678]  Thaler, D., Fenner, B., and B. Quinn, "Socket Interface
              Extensions for Multicast Source Filters", RFC 3678,
              January 2004.

   [RFC3775]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
              in IPv6", RFC 3775, June 2004.

   [RFC3776]  Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to
              Protect Mobile IPv6 Signaling Between Mobile Nodes and
              Home Agents", RFC 3776, June 2004.

   [RFC3971]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
              Neighbor Discovery (SEND)", RFC 3971, March 2005.

   [RFC3972]  Aura, T., "Cryptographically Generated Addresses (CGA)",
              RFC 3972, March 2005.




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   [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
              More-Specific Routes", RFC 4191, November 2005.

   [RFC4302]  Kent, S., "IP Authentication Header", RFC 4302,
              December 2005.

   [RFC4338]  DeSanti, C., Carlson, C., and R. Nixon, "Transmission of
              IPv6, IPv4, and Address Resolution Protocol (ARP) Packets
              over Fibre Channel", RFC 4338, January 2006.

   [RFC4380]  Huitema, C., "Teredo: Tunneling IPv6 over UDP through
              Network Address Translations (NATs)", RFC 4380,
              February 2006.

   [RFC4429]  Moore, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", RFC 4429, April 2006.

   [RFC4584]  Chakrabarti, S. and E. Nordmark, "Extension to Sockets API
              for Mobile IPv6", RFC 4584, July 2006.

   [RFC4821]  Mathis, M. and J. Heffner, "Packetization Layer Path MTU
              Discovery", RFC 4821, March 2007.

   [RFC4877]  Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
              IKEv2 and the Revised IPsec Architecture", RFC 4877,
              April 2007.

   [RFC4884]  Bonica, R., Gan, D., Tappan, D., and C. Pignataro,
              "Extended ICMP to Support Multi-Part Messages", RFC 4884,
              April 2007.

   [RFC4944]  Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
              "Transmission of IPv6 Packets over IEEE 802.15.4
              Networks", RFC 4944, September 2007.

   [RFC5006]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
              "IPv6 Router Advertisement Option for DNS Configuration",
              RFC 5006, September 2007.

   [RFC5014]  Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6
              Socket API for Source Address Selection", RFC 5014,
              September 2007.

   [RFC5072]  S.Varada, Haskins, D., and E. Allen, "IP Version 6 over
              PPP", RFC 5072, September 2007.

   [RFC5121]  Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S.
              Madanapalli, "Transmission of IPv6 via the IPv6



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              Convergence Sublayer over IEEE 802.16 Networks", RFC 5121,
              February 2008.

   [RFC5555]  Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
              Routers", RFC 5555, June 2009.

   [USGv6]    National Institute of Standards and Technology, "A Profile
              for IPv6 in the U.S. Government - Version 1.0", July 2008,
              <http://www.antd.nist.gov/usgv6/usgv6-v1.pdf>.


Authors' Addresses

   Ed Jankiewicz
   SRI International, Inc.
   1161 Broad Street - Suite 212
   Shrewsbury, NJ  07702
   USA

   Phone: 443-502-5815
   Email: edward.jankiewicz@sri.com


   John Loughney
   Nokia
   955 Page Mill Road
   Palo Alto  94303
   USA

   Phone: +1 650 283 8068
   Email: john.loughney@nokia.com


   Thomas Narten
   IBM Corporation
   3039 Cornwallis Ave.
   PO Box 12195
   Research Triangle Park, NC  27709-2195
   USA

   Phone: +1 919 254 7798
   Email: narten@us.ibm.com









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