Goals for IPv6 Site-Multihoming Architectures
RFC 3582
Document | Type | RFC - Informational (August 2003; No errata) | |
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Authors | Joe Abley , Vijay Gill , Benjamin Black | ||
Last updated | 2015-10-14 | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3582 (Informational) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Randy Bush | ||
Send notices to | <smd@ab.use.net> |
Network Working Group J. Abley Request for Comments: 3582 ISC Category: Informational B. Black Layer8 Networks V. Gill AOL Time Warner August 2003 Goals for IPv6 Site-Multihoming Architectures Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document outlines a set of goals for proposed new IPv6 site- multihoming architectures. It is recognised that this set of goals is ambitious and that some goals may conflict with others. The solution or solutions adopted may only be able to satisfy some of the goals presented here. 1. Introduction Site-multihoming, i.e., connecting to more than one IP service provider, is an essential component of service for many sites which are part of the Internet. Current IPv4 site-multihoming practices have been added on to the CIDR architecture [1], which assumes that routing table entries can be aggregated based upon a hierarchy of customers and service providers. However, it appears that this hierarchy is being supplanted by a dense mesh of interconnections [6]. Additionally, there has been an enormous growth in the number of multihomed sites. For purposes of redundancy and load-sharing, the multihomed address blocks are introduced into the global table even if they are covered by a provider aggregate. This contributes to the rapidly-increasing size of both the global routing table and the turbulence exhibited within it, and places stress on the inter-provider routing system. Abley, et al. Informational [Page 1] RFC 3582 IPv6 Site-Multihoming Goals August 2003 Continued growth of both the Internet and the practice of site- multihoming will seriously exacerbate this stress. The site- multihoming architecture for IPv6 should allow the routing system to scale more pleasantly. 2. Terminology A "site" is an entity autonomously operating a network using IP, and in particular, determining the addressing plan and routing policy for that network. This definition is intended to be equivalent to "enterprise" as defined in [2]. A "transit provider" operates a site that directly provides connectivity to the Internet to one or more external sites. The connectivity provided extends beyond the transit provider's own site. A transit provider's site is directly connected to the sites for which it provides transit. A "multihomed" site is one with more than one transit provider. "Site-multihoming" is the practice of arranging a site to be multihomed. The term "re-homing" denotes a transition of a site between two states of connectedness due to a change in the connectivity between the site and its transit providers' sites. 3. Multihoming Goals 3.1. Capabilities of IPv4 Multihoming The following capabilities of current IPv4 multihoming practices should be supported by an IPv6 multihoming architecture. 3.1.1. Redundancy By multihoming, a site should be able to insulate itself from certain failure modes within one or more transit providers, as well as failures in the network providing interconnection among one or more transit providers. Infrastructural commonalities below the IP layer may result in connectivity which is apparently diverse, sharing single points of failure. For example, two separate DS3 circuits ordered from different suppliers and connecting a site to independent transit providers may share a single conduit from the street into a building; in this case, physical disruption (sometimes referred to as "backhoe-fade") of both circuits may be experienced due to a single incident in the street. The two circuits are said to "share fate". Abley, et al. Informational [Page 2] RFC 3582 IPv6 Site-Multihoming Goals August 2003 The multihoming architecture should accommodate (in the general case, issues of shared fate notwithstanding) continuity of connectivity during the following failures: o Physical failure, such as a fiber cut, or router failure, o Logical link failure, such as a misbehaving router interface, o Routing protocol failure, such as a BGP peer reset, o Transit provider failure, such as a backbone-wide IGP failure, and o Exchange failure, such as a BGP reset on an inter-providerShow full document text