Internet DRAFT - draft-behringer-autonomic-addressing
draft-behringer-autonomic-addressing
ANIMA M. Behringer
Internet-Draft Cisco Systems
Intended status: Standards Track April 21, 2015
Expires: October 23, 2015
An Autonomic IPv6 Addressing Scheme
draft-behringer-autonomic-addressing-00
Abstract
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
aggregatable. This document is for discussion right now; the final
addressing scheme should probably move into
[I-D.behringer-anima-reference-model].
Status of This Memo
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This Internet-Draft will expire on October 23, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. The Addressing Scheme . . . . . . . . . . . . . . . . . . . . 3
3. Algorithm to Calculate Unique Addresses . . . . . . . . . . . 3
4. Address Hierarchy . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
In an Autonomic Network, as defined in
[I-D.irtf-nmrg-autonomic-network-definitions], 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.
This scheme targets exclusively loopback addresses of nodes. We
assume that link-local addressing is used on the interfaces of links.
The addressing scheme allows the definitions of zones for the purpose
of aggregation of address space. This makes it possible to start
with a flat address scheme, and introduce a hierarchy later if and
when required.
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2. The Addressing Scheme
We assume that each node has two unique properties:
o A domain name: All devices in a domain share the same domain name.
o A node name: This name MUST be unique inside the domain.
An example of a full node name is "node17.domain.com", where "node17"
is the node name and "domain.com" is the domain name. Inside
"domain.com" "node17" MUST be unique.
The addressing scheme follows the ULA address definition, as
specified in [RFC4193], and has the following format:
8 40 3 13 64
+--+--------------+------+---------+--------------------------------+
|FD| hash(domain) | Type | Zone ID | Device ID |
+--+--------------+------+---------+--------------------------------+
Figure 1: Address Scheme
The fields are defined as follows:
o FD: The prefix to indicate that the address is a ULA prefix.
o hash(domain): A pseudo-random 40 bit value representing the
domain. See Section 3 for details on the way this value is
derived.
o Type: Set to 000. This field allows different address sub-types
in the future.
o Zone ID: If set to all zero bits: Flat addressing scheme. Any
other value indicates a zone. See section Section 4
o Device ID: A unique 64 bit value for the device. See Section 3
for details on the way this value is derived.
3. Algorithm to Calculate Unique Addresses
The "hash(domain)" part of the address is calculated as the first 40
bits of the MD5 hash of the domain name, in the example "domain.com".
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
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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
number.
If required, other schemas can be defined in the future, using a new
"type" value.
4. 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
areas.
5. Security Considerations
tbc
6. Acknowledgements
The following people have been involved in developing this scheme:
Toerless Eckert, Steinthor Bjarnason, BL Balaji, Ravi Kumar
Vadapalli.
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7. References
[I-D.behringer-anima-reference-model]
Behringer, M., Carpenter, B., and T. Eckert, "A Reference
Model for Autonomic Networking", draft-behringer-anima-
reference-model-00 (work in progress), October 2014.
[I-D.behringer-autonomic-control-plane]
Behringer, M., Bjarnason, S., BL, B., and T. Eckert, "An
Autonomic Control Plane", draft-behringer-autonomic-
control-plane-00 (work in progress), June 2014.
[I-D.irtf-nmrg-autonomic-network-definitions]
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.
Author's Address
Michael H. Behringer
Cisco Systems
Building D, 45 Allee des Ormes
Mougins 06250
France
Email: mbehring@cisco.com
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