Considerations For Using Unique Local Addresses
draft-ietf-v6ops-ula-usage-considerations-02
Internet Engineering Task Force B. Liu
Internet-Draft S. Jiang
Intended status: Informational Huawei Technologies
Expires: September 14, 2017 March 13, 2017
Considerations For Using Unique Local Addresses
draft-ietf-v6ops-ula-usage-considerations-02
Abstract
This document provides considerations for using IPv6 Unique Local
Addresses (ULAs). Based on an analysis of different ULA usage
scenarios, this document identifies use cases where ULA addresses are
helpful as well as potential problems caused by using them.
Status of This Memo
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Liu & Jiang Expires September 14, 2017 [Page 1]
Internet-Draft ULA Usage March 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. General Considerations For Using ULAs . . . . . . . . . . . . 3
3.1. Do Not Treat ULA Equal to RFC1918 . . . . . . . . . . . . 3
3.2. Using ULAs in a Limited Scope . . . . . . . . . . . . . . 4
4. Analysis and Operational Considerations for Scenarios Using
ULAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. ULA-only in Isolated Networks . . . . . . . . . . . . . . 4
4.2. ULA+PA in Connected Networks . . . . . . . . . . . . . . 5
4.3. ULA-Only in Connected Networks . . . . . . . . . . . . . 7
4.4. Some Specific Use Cases . . . . . . . . . . . . . . . . . 8
4.4.1. Special Routing . . . . . . . . . . . . . . . . . . . 8
4.4.2. Used as Identifier . . . . . . . . . . . . . . . . . 8
4.5. IPv4 Co-existence Considerations . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
Unique Local Addresses (ULA) is defined in [RFC4193], and it is an
alternative to site-local address (deprecated in [RFC3879]). ULAs
have the following features:
- Automatically Generated
ULA prefixes can be automatically generated using the algorithms
described in [RFC4193]. This feature allows automatic prefix
allocation. Thus one can get a network working immediately
without applying for prefix(es) from an RIR/LIR (Regional Internet
Registry/Local Internet Registry).
- Globally Unique
ULAs are defined as a global scope address space. However, they
are not intended to be used globally on the public Internet; in
contrast, they are mostly used locally, for example, in isolated
networks, internal networks, or VPNs.
ULAs are intended to have an extremely low probability of
collision. The randomization of 40 bits in a ULA prefix is
considered sufficient enough to ensure a high degree of uniqueness
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