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. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 30, 2015. Copyright Notice Copyright (c) 2014 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 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Liu Expires April 30, 2015 [Page 1] Internet-Draft draft-liu-ula-site-anycast-00 October 2014 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. Liu Expires April 30, 2015 [Page 2] Internet-Draft draft-liu-ula-site-anycast-00 October 2014 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. Liu Expires April 30, 2015 [Page 3] Internet-Draft draft-liu-ula-site-anycast-00 October 2014 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 Liu Expires April 30, 2015 [Page 4]