Scalable Support for Multi-homed Multi-provider Connectivity (RFC2260)
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
T. Bates: AUTHOR [+1]
This document describes addressing and routing strategies for multi- homed enterprises attached to multiple Internet Service Providers (ISPs) that are intended to reduce the routing overhead due to these enterprises in the global Internet routing system. This memo provides information for the Internet community. It does not specify an Internet standard of any kind.
Network Working Group T. Bates Request for Comments: 2260 Cisco Systems Category: Informational Y. Rekhter Cisco Systems January 1998
Scalable Support for Multi-homed Multi-provider Connectivity
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 (C) The Internet Society (1998). All Rights Reserved.
This document describes addressing and routing strategies for multi- homed enterprises attached to multiple Internet Service Providers (ISPs) that are intended to reduce the routing overhead due to these enterprises in the global Internet routing system.
An enterprise may acquire its Internet connectivity from more than one Internet Service Provider (ISP) for some of the following reasons. Maintaining connectivity via more than one ISP could be viewed as a way to make connectivity to the Internet more reliable. This way when connectivity through one of the ISPs fails, connectivity via the other ISP(s) would enable the enterprise to preserve its connectivity to the Internet. In addition to providing more reliable connectivity, maintaining connectivity via more than one ISP could also allow the enterprise to distribute load among multiple connections. For enterprises that span wide geographical area this could also enable better (more optimal) routing.
The above considerations, combined with the decreasing prices for the Internet connectivity, motivate more and more enterprises to become multi-homed to multiple ISPs. At the same time, the routing overhead that such enterprises impose on the Internet routing system becomes more and more significant. Scaling the Internet, and being able to support a growing number of such enterprises demands mechanism(s) to contain this overhead. This document assumes that an approach where routers in the "default-free" zone of the Internet would be required
Bates & Rekhter Informational [Page 1]
RFC 2260 Multihoming January 1998
to maintain a route for every multi-homed enterprise that is connected to multiple ISPs does not provide an adequate scaling. Moreover, given the nature of the Internet, this document assumes that any approach to handle routing for such enterprises should minimize the amount of coordination among ISPs, and especially the ISPs that are not directly connected to these enterprises.
There is a difference of opinions on whether the driving factors behind multi-homing to multiple ISPs could be adequately addressed by multi-homing just to a single ISP, which would in turn eliminate the negative impact of multi-homing on the Internet routing system. Discussion of this topic is beyond the scope of this document.
The focus of this document is on the routing and addressing strategies that could reduce the routing overhead due to multi-homed enterprises connected to multiple ISPs in the Internet routing system.
The strategies descri...