IPv4 Multihoming Practices and Limitations
RFC 4116
Document | Type | RFC - Informational (July 2005; No errata) | |
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Authors | Joe Abley , Elwyn Davies , Vijay Gill , Kurt Lindqvist , Benjamin Black | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4116 (Informational) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | David Kessens | ||
Send notices to | brc@zurich.ibm.com |
Network Working Group J. Abley Request for Comments: 4116 ISC Category: Informational K. Lindqvist Netnod Internet Exchange E. Davies Independent Researcher B. Black Layer8 Networks V. Gill AOL July 2005 IPv4 Multihoming Practices and Limitations 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 (2005). Abstract Multihoming is an essential component of service for many Internet sites. This document describes some implementation strategies for multihoming with IPv4 and enumerates features for comparison with other multihoming proposals (particularly those related to IPv6). Abley, et al. Informational [Page 1] RFC 4116 IPv4 Multihoming July 2005 Table of Contents 1. Introduction ....................................................3 2. Terminology .....................................................3 3. IPv4 Multihoming Practices ......................................4 3.1. Multihoming with BGP .......................................4 3.1.1. Addressing Considerations ...........................4 3.1.2. AS Number Considerations ............................6 3.2. Multiple Attachments to a Single Transit Provider ..........6 3.3. NAT- or RFC2260-based Multihoming ..........................7 4. Features of IPv4 Multihoming ....................................7 4.1. Redundancy .................................................7 4.2. Load Sharing ...............................................8 4.3. Performance ................................................8 4.4. Policy .....................................................8 4.5. Simplicity .................................................9 4.6. Transport-Layer Survivability ..............................9 4.7. Impact on DNS ..............................................9 4.8. Packet Filtering ...........................................9 4.9. Scalability ................................................9 4.10. Impact on Routers ........................................10 4.11. Impact on Hosts ..........................................10 4.12. Interactions between Hosts and the Routing System ........10 4.13. Operations and Management ................................10 4.14. Cooperation between Transit Providers ....................10 5. Security Considerations ........................................10 6. Acknowledgements ...............................................10 7. Informative References .........................................11 Abley, et al. Informational [Page 2] RFC 4116 IPv4 Multihoming July 2005 1. Introduction Multihoming is an important component of service for many Internet sites. Current IPv4 multihoming practices have been added on to the Classless Inter Domain Routing (CIDR) architecture [RFC1519], which assumes that routing table entries can be aggregated based upon a hierarchy of customers and service providers. Multihoming is a mechanism by which sites can satisfy a number of high-level requirements. It is widely used in the IPv4 Internet. There are some practical limitations, however, including concerns as to how it would scale with future Internet growth. This document aims to document common IPv4 multihoming practices and enumerate their features for comparison with other multihoming approaches. There are a number of different ways to route and manage traffic in and out of a multihomed site: the majority rely on the routing policy capabilities of the inter-domain routing protocol, the Border Gateway Protocol, version 4 (BGP) [RFC1771]. This document also discusses a multi-homing strategy which does not rely on the capabilities of BGP. 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 toShow full document text