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Versions: (draft-behringer-autonomic-addressing) 00 01 02 03

ANIMA                                                       M. Behringer
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                           June 18, 2015
Expires: December 20, 2015

                  An Autonomic IPv6 Addressing Scheme


   This document describes a generic IPv6 addressing scheme which is
   suitable for autonomic nodes, where node addressing must not depend
   on a centrally managed scheme.  It assumes a unique domain name and
   device name, and automatically derives a unique IPv6 address from
   those.  The scheme allows for a flat address hierarchy as well as
   optionally, when required, the definition of zones which are

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on December 20, 2015.

Copyright Notice

   Copyright (c) 2015 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
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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements and Assumptions  . . . . . . . . . . . . . . . .   2
   3.  Fundamental Concepts of Autonomic Addressing  . . . . . . . .   3
   4.  The Base Addressing Scheme  . . . . . . . . . . . . . . . . .   4
   5.  Possible Sub-Schemes  . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Sub-Scheme 1  . . . . . . . . . . . . . . . . . . . . . .   5
     5.2.  Sub-Scheme 2  . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Address Hierarchy . . . . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   In an Autonomic Network, as defined in
   [I-D.irtf-nmrg-autonomic-network-definitions], and specified in more
   detail in [I-D.behringer-anima-reference-model], one of the design
   goals is to minimise central functions.  Address management
   traditionally is a centralised function, where addresses are assigned
   to nodes.  In this document we assume that each node has already been
   assigned with a unique node name, and a domain name.  We introduce an
   addressing scheme and an algorithm that allows the calculation of a
   unique IPv6 ULA address inside a domain.  In other words, once a
   device has a unique node and domain name, this addressing scheme and
   algorithm allows for distributed self-management of addressing inside
   a network.

   The addressing scheme described here is specifically designed for
   both the data plane of a network, as well as the Autonomic Control
   Plane (ACP; see [I-D.behringer-autonomic-control-plane]).  It is for
   communication inside the domain only, specifically to support self-
   management functions.

2.  Requirements and Assumptions

   An autonomic addressing scheme has the following requirements:

   o  Zero-touch for simple networks: Simple networks should have
      complete self-management of addressing, and not require any
      central address management, tools, or address planning.

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   o  Low-touch for complex networks: If complex networks require
      operator input for autonomic address management, it should be
      limited to high level guidance only, expressed in Intent.

   o  Flexibility: The addressing scheme must be flexible enough for
      nodes to be able to move around, for the network to grow, split
      and merge.

   o  Robustness: It should be as hard as possible for an administrator
      to negatively affect addressing (and thus connectivity) in the
      autonomic context.

   o  Support for virtualization: Autonomic Nodes may support Autonomic
      Service Agents in different virtual machines or containers.  The
      addressing scheme should support this architecture.

   o  Simplicity: To make engineering simpler, and to give the human
      administrator an easy way to trouble-shoot autonomic functions.

   o  Scale: The proposed scheme should work in any network of any size.

   o  Upgradability: The scheme must be able to support different
      addressing concepts in the future.

   We assume that each node has a unique domain name and a unique node
   name inside that domain, for example "node17.domain.com".

3.  Fundamental Concepts of Autonomic Addressing

   IPv6 only: Autonomic processes should use exclusively IPv6, for
   simplicity reasons.

   Usage: Autonomic addresses are exclusively used for self-management
   functions inside a trusted domain.  They are not used for user
   traffic.  Communications with entities outside the trusted domain use
   another address space, for example normally managed routable address

   Separation: Autonomic address space is used separately from user
   address space and other address realms.  This supports the robustness

   Loopback-only: Only loopback interfaces of autonomic nodes carry a
   routable address; all other interfaces exclusively use IPv6 link
   local for autonomic functions.  The usage of IPv6 link local
   addressing is discussed in [RFC7404].

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   Use-ULA: For loopback interfaces of autonomic nodes, we use Unique
   Local Addresses (ULA), as specified in [RFC4193].  An alternative
   scheme was discussed, using assigned ULA addressing.  The consensus
   was to use standard ULA, because it was deemed to be sufficient.

   No external connectivity: They do not provide access to the Internet.
   If a node requires further reaching connectivity, it should use
   another, traditionally managed address scheme in parallel.

4.  The Base Addressing Scheme

   The Base ULA addressing scheme for autonomic nodes has the following

     8      40          3                     77
   |FD| hash(domain) | Type |             (sub-scheme)                 |

                     Figure 1: Base Addressing Scheme

   The first 48 bits follow the ULA scheme, as defined in [RFC4193], to
   which a type field is added:

   o  "FD" identifies a locally defined ULA address.

   o  The "global ID" is set here to be a hash of the domain name, which
      results in a pseudo-random 40 bit value.  It is calculated as the
      first 40 bits of the MD5 hash of the domain name, in the example

   o  Type: Set to 000 (3 zero bits).  This field allows different
      address sub-schemes in the future.  The goal is to start with a
      minimal number of sub-scheme initially, but to allow for
      extensions later if and when required.  This addresses the
      "upgradability" requirement.  Assignment of types for this field
      should be maintained by IANA.

5.  Possible Sub-Schemes

   The sub-schemes listed here are not intended to be all supported
   initially, but are listed for discussion.  The final document should
   define ideally only a single sub-scheme for now, and leave the other
   "types" for later assignment.

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5.1.  Sub-Scheme 1

             51                 13                    64
   |    (base scheme)       | Zone ID |         Device ID              |

                       Figure 2: Addressing Scheme 1

   The fields are defined as follows: [Editor's note: The lengths of the
   fields is for discussion.]

   o  Zone ID: If set to all zero bits: Flat addressing scheme.  Any
      other value indicates a zone.  See section Section 6 on how this
      field is used in detail.

   o  Device ID: A unique value for each device.

   The device ID is derived as follows: In an Autonomic Network, a
   registrar is enrolling new devices.  As part of the enrolment process
   the registrar assigns a number to the device, which is unique for
   this registrar, but not necessarily unique in the domain.  The 64 bit
   device ID is then composed as:

   o  48 bit: Registrar ID, a number unique inside the domain that
      identifies the registrar which assigned the name to the device.  A
      MAC address of the registrar can be used for this purpose.

   o  16 bit: Device ID, a number which is unique for a given registrar,
      to identify the device.  This can be a sequentially assigned

   The "device ID" itself is unique in a domain (i.e., the Zone-ID is
   not required for uniqueness).  Therefore, a device can be addressed
   either as part of a flat hierarchy (zone ID = 0), or with an
   aggregation scheme (any other zone ID).  A address with zone-ID could
   be interpreted as an identifier, with another zone-ID as a locator.

5.2.  Sub-Scheme 2

             51                 13                    64-V           ?
   |    (base scheme)       | Zone ID |         Device ID          | V |

                       Figure 3: Addressing Scheme 2

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   The fields are defined as follows: [Editor's note: The lengths of the
   fields is for discussion.]

   o  Zone ID: As in sub-scheme 1.

   o  Device ID: As in sub-scheme 1.

   o  V: Virtualization bit(s): 1 or more bits that indicate a virtual
      context on an autonomic node.

   In addition the scheme 1 (Section 5.1), this scheme allows the direct
   addressing of specific virtual containers / VMs on an autonomic node.
   An increasing number of hardware platforms have a distributed
   architecture, with a base OS for the node itself, and the support for
   hardware blades with potentially different OSs.  The VMs on the
   blades could be considered as separate autonomic nodes, in which case
   it would make sense to be able to address them directly.  Autonomic
   Service Agents (ASAs) could be instantiated in either the base OS, or
   one of the VMs on a blade.  This addressing scheme allows for the
   easy separation of the hardware context.

   The location of the V bit(s) at the end of the address allows to
   announce a single prefix for each autonomic node, while having
   separate virtual contexts addressable directly.

6.  Address Hierarchy

   The "zone ID" allows for the definition of a simple address
   hierarchy.  If set to zero, the address scheme is flat.  In this
   case, the addresses primarily act as identifiers for the nodes.  Used
   like this, aggregation is not possible.

   If aggregation is required, the 13 bit value allows for up to 8191
   zones.  (Theoretically, the 13 bits for the zone ID would allow also
   for two levels of zones, introducing a sub-hierarchy.  We do not
   think this is required at this point, but a new type could be used in
   the future to support such a scheme.)

   Another way to introduce hierarchy is to use sub-domains in the
   naming scheme.  The node names "node17.subdomainA.domain.com" and
   "node4.subdomainB.domain.com" would automatically lead to different
   ULA prefixes, which can be used to introduce a routing hierarchy in
   the network, assuming that the subdomains are aligned with routing

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7.  IANA Considerations

   The type field in the base addressing scheme should be maintained by

8.  Security Considerations


9.  Acknowledgements

   The following people have been involved in developing this scheme:
   Toerless Eckert, Steinthor Bjarnason, BL Balaji, Ravi Kumar

10.  References

              Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
              and B. Liu, "A Reference Model for Autonomic Networking",
              draft-behringer-anima-reference-model-02 (work in
              progress), June 2015.

              Behringer, M., Bjarnason, S., BL, B., and T. Eckert, "An
              Autonomic Control Plane", draft-behringer-autonomic-
              control-plane-00 (work in progress), June 2014.

              Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
              Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
              Networking - Definitions and Design Goals", draft-irtf-
              nmrg-autonomic-network-definitions-07 (work in progress),
              March 2015.

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, October 2005.

   [RFC7404]  Behringer, M. and E. Vyncke, "Using Only Link-Local
              Addressing inside an IPv6 Network", RFC 7404, November

Author's Address

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   Michael H. Behringer
   Cisco Systems
   Building D, 45 Allee des Ormes
   Mougins  06250

   Email: mbehring@cisco.com

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