Internet DRAFT - draft-liu-ula-site-anycast
draft-liu-ula-site-anycast
v6ops B. Liu
Internet-Draft Huawei Technologies
Intended status: Best Current Practice October 27, 2014
Expires: April 30, 2015
ULAs Used for Site-Local Anycast Addresses
draft-liu-ula-site-anycast-00
Abstract
This document proposes to use ULAs for the anycast addresses based on
site-local addresses which have been deprecated.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 30, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. ULA Alternatives . . . . . . . . . . . . . . . . . . . . . . 2
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
6.1. Normative References . . . . . . . . . . . . . . . . . . 3
6.2. Informative References . . . . . . . . . . . . . . . . . 3
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
Anycast is a new type of address along with unicast and multicast in
IPv6. Different nodes could be assigned with one same anycast
address. When a packet's destination is the anycast address, a could
be delivered to the "nearest" interface among all the interfaces
assigned to the anycast address. This kind of delivery is achieved
by notion of "distance" determined by the routing protocols in use.
An anycast address may be used to allow nodes to access one of a
collection of servers providing a well-known service, without manual
configuration in each node of the list of servers. The most typical
application is in Domain Name System [RFC1035] that Most of the root
DNS server have used anycast addresses. As well as the root servers,
[RFC4339] section 3.3 discusses the approach of using a well-known
anycast address in DNS recursive resolvers.
However, since site-local IPv6 addresses are deprecated by [RFC3879],
the site-local well-know anycast use case becomes unvalid as well.
This document proposes to use ULAs as alternatives for site-local
anycast use cases.
2. ULA Alternatives
There are mainly two reasons to use ULAs as the alternatives:
o ULAs are normally used within a site scope. The famous ULA prefix
could ensure the ULAs could be easily filtered by the site
boudary. This feature fits the site-scoped DNS recursive
resolvers very well.
o ULAs are provider independent so that stable site-local
communications could be enabled regardless of renumbering caused
by the ISPs.
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3. Security Considerations
TBD.
4. IANA Considerations
This document requires no action of IANA.
5. Acknowledgements
This topic was originally raised by Dave Thaler. Useful comments
were received from Brian Carpenter, Alexandru Petrescu and Lorenzo
Colitti on this topic.
This document was produced using the xml2rfc tool [RFC2629].
6. References
6.1. Normative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC3879] Huitema, C. and B. Carpenter, "Deprecating Site Local
Addresses", RFC 3879, September 2004.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, October 2005.
6.2. Informative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2902] Deering, S., Hares, S., Perkins, C., and R. Perlman,
"Overview of the 1998 IAB Routing Workshop", RFC 2902,
August 2000.
[RFC4339] Jeong, J., "IPv6 Host Configuration of DNS Server
Information Approaches", RFC 4339, February 2006.
[RFC7094] McPherson, D., Oran, D., Thaler, D., and E. Osterweil,
"Architectural Considerations of IP Anycast", RFC 7094,
January 2014.
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Author's Address
Bing Liu
Huawei Technologies
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: leo.liubing@huawei.com
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