draft-ietf-ipv6-node-requirements-08.txt

非常好的dns解析软件

IPv6 Working Group                                 John Loughney (ed)
Internet-Draft                                                  Nokia
                                                     January 14, 2004

Expires: July 14, 2004



                         IPv6 Node Requirements
                draft-ietf-ipv6-node-requirements-08.txt




Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   Drafts.

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Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

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.





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Table of Contents

   1.   Introduction
   1.1 Requirement Language
   1.2  Scope of this Document
   1.3  Description of IPv6 Nodes
   2.   Abbreviations Used in This Document
   3.   Sub-IP Layer
   3.1  Transmission of IPv6 Packets over Ethernet Networks - RFC2464
   3.2  IP version 6 over PPP - RFC2472
   3.3  IPv6 over ATM Networks - RFC2492
   4.   IP Layer
   4.1  Internet Protocol Version 6 - RFC2460
   4.2  Neighbor Discovery for IPv6 - RFC2461
   4.3  Path MTU Discovery & Packet Size
   4.4  ICMP for the Internet Protocol Version 6 (IPv6) - RFC2463
   4.5  Addressing
   4.6  Multicast Listener Discovery (MLD) for IPv6 - RFC2710
   5.   Transport and DNS
   5.1  Transport Layer
   5.2  DNS
   5.3  Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
   6.   IPv4 Support and Transition
   6.1  Transition Mechanisms
   7.   Mobility
   8.   Security
   8.1  Basic Architecture
   8.2  Security Protocols
   8.3  Transforms and Algorithms
   8.4  Key Management Methods
   9.   Router Functionality
   9.1  General
   10.  Network Management
   10.1 MIBs
   11.  Security Considerations
   12.  References
   12.1 Normative
   12.2 Non-Normative
   13.  Authors and Acknowledgements
   14.  Editor's Address
   Notices










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1. Introduction

   The goal of this document is to define the common functionality
   required from both IPv6 hosts and routers.  Many IPv6 nodes will
   implement optional or additional features, but all IPv6 nodes can be
   expected to implement the mandatory requirements listed in this
   document.

   This document tries to avoid discussion of protocol details, and
   references RFCs for this purpose.  In case of any conflicting text,
   this document takes less precedence than the normative RFCs, unless
   additional clarifying text is included in this document.

   Although the document points to different specifications, it should
   be noted that in most cases, the granularity of requirements are
   smaller than a single specification, as many specifications define
   multiple, independent pieces, some of which may not be mandatory.

   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:

      Be conservative in what you do, be liberal in what you accept from
      others [RFC-793].

1.1 Requirement 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 [RFC-2119].

1.2 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, in order
   to ensure interoperability.

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

1.3 Description of IPv6 Nodes

   From Internet Protocol, Version 6 (IPv6) Specification [RFC-2460] we
   have the following definitions:

      Description of an IPv6 Node




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       - 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.

2. 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

   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

3. Sub-IP Layer



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   An IPv6 node must include support for one or more IPv6 link-layer
   specifications.  Which link-layer specifications are included 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.  This section highlights some major
   layer 2 technologies and is not intended to be complete.

3.1 Transmission of IPv6 Packets over Ethernet Networks - RFC2464

   Nodes supporting IPv6 over Ethernet interfaces MUST implement
   Transmission of IPv6 Packets over Ethernet Networks [RFC-2464].

3.2 IP version 6 over PPP - RFC2472

   Nodes supporting IPv6 over PPP MUST implement IPv6 over PPP [RFC-
   2472].

3.3 IPv6 over ATM Networks - RFC2492

   Nodes supporting IPv6 over ATM Networks MUST implement IPv6 over ATM
   Networks [RFC-2492].  Additionally, RFC 2492 states:

      A minimally conforming IPv6/ATM driver SHALL support the PVC mode
      of operation. An IPv6/ATM driver that supports the full SVC mode
      SHALL also support PVC mode of operation.

4. IP Layer

4.1 Internet Protocol Version 6 - RFC2460

   The Internet Protocol Version 6 is specified in [RFC-2460]. This
   specification MUST be supported.

   Unrecognized options in Hop-by-Hop Options or Destination Options
   extensions 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 receving IPv6 packets; forwarding functionality MAY be
   supported

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



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      A full implementation of IPv6 includes implementation of the
      following extension headers: Hop-by-Hop Options, Routing (Type 0),
      Fragment, Destination Options, Authentication and Encapsulating
      Security Payload. [RFC-2460]

   An IPv6 node MUST be able to process these headers.  It should be
   noted that there is some discussion about the use of Routing Headers
   and possible security threats [IPv6-RH] caused by them.

4.2 Neighbor Discovery for IPv6 - RFC2461

   Neighbor Discovery SHOULD be supported.  RFC 2461 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. Router Discovery MUST be supported for
   implementations.

   Prefix Discovery is how hosts discover the set of address prefixes
   that define which destinations are on-link for an attached link.
   Prefix discovery MUST be supported for implementations. Neighbor
   Unreachability Detection (NUD) MUST be supported for all paths
   between hosts and neighboring nodes. It is not required for paths
   between routers.  However, when a node receives a unicast Neighbor
   Solicitation (NS) message (that may be a NUD's NS), the node MUST
   respond to it (i.e. send a unicast Neighbor Advertisement).

   Duplicate Address Detection MUST be supported on all links supporting
   link-layer multicast (RFC2462 section 5.4 specifies DAD MUST take
   place on all unicast addresses).

   A host implementation MUST support sending Router Solicitations.

   Receiving and processing Router Advertisements MUST be supported for



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   host implementations. The ability to understand specific Router
   Advertisement options is dependent on supporting the specification
   where the RA is specified.

   Sending and Receiving Neighbor Solicitation (NS) and Neighbor
   Advertisement (NA) MUST be supported. NS and NA messages are required
   for Duplicate Address Detection (DAD).

   Redirect functionality SHOULD be supported. If the node is a router,
   Redirect functionality MUST be supported.

4.3 Path MTU Discovery & Packet Size

4.3.1 Path MTU Discovery - RFC1981

   Path MTU Discovery [RFC-1981] SHOULD be supported, though minimal
   implementations MAY choose to not support it and avoid large packets.
   The rules in RFC 2460 MUST be followed for packet fragmentation and
   reassembly.

4.3.2 IPv6 Jumbograms - RFC2675

   IPv6 Jumbograms [RFC-2675] MAY be supported.

4.4  ICMP for the Internet Protocol Version 6 (IPv6) - RFC2463

   ICMPv6 [RFC-2463] MUST be supported.

4.5 Addressing

4.5.1 IP Version 6 Addressing Architecture - RFC3513

   The IPv6 Addressing Architecture [RFC-3513] MUST be supported.

4.5.2 IPv6 Stateless Address Autoconfiguration - RFC2462