Autonomous confederations (RFC0975)
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2019-Feb-14
Internet Society Requests For Comment (RFCs)
This RFC proposes enhancements to the Exterior Gateway Protocol (EGP) to support a simple, multiple-level routing capability while preserving the robustness features of the current EGP model. The enhancements generalize the concept of core system to include multiple communities of autonomous systems, called autonomous confederations. Discussion and suggestions for improvement are requested.
Network Working Group D. L. Mills Request for Comments: 975 M/A-COM Linkabit February 1986
Status of This Memo
This RFC proposes certain enhancements of the Exterior Gateway Protocol (EGP) to support a simple, multiple-level routing capability while preserving the robustness features of the current EGP model. It requests discussion and suggestions for improvements. Distribution of this memo is unlimited.
The enhancements, which do not require retrofits in existing implementations in order to interoperate with enhanced implementations, in effect generalize the concept of core system to include multiple communities of autonomous systems, called autonomous confederations. Autonomous confederations maintain a higher degree of mutual trust than that assumed between autonomous systems in general, including reasonable protection against routing loops between the member systems, but allow the routing restrictions of the current EGP model to be relaxed.
The enhancements involve the "hop count" or distance field of the EGP Update message, the interpretation of which is not covered by the current EGP model. This field is given a special interpretation within each autonomous confederation to support up to three levels of routing, one within the autonomous system, a second within the autonomous confederation and an optional third within the universe of confederations.
1. Introduction and Background
The historical development of Internet exterior-gateway routing algorithms began with a rather rigid and restricted topological model which emphasized robustness and stability at the expense of routing dynamics and flexibility. Evolution of robust and dynamic routing algorithms has since proved extraordinarily difficult, probably due more to varying perceptions of service requirements than to engineering problems.
The original exterior-gateway model suggested in RFC-827  and subsequently refined in RFC-888  severely restricted the Internet topology essentially to a tree structure with root represented by the BBN-developed "core" gateway system. The most important characteristic of the model was that debilitating resource-consuming routing loops between clusters of gateways (called autonomous
Mills [Page 1]
RFC 975 February 1986 Autonomous Confederations
systems) could not occur in a tree-structured topology. However, the administrative and enforcement difficulties involved, not to mention the performance liabilities, made widespread implementation impractical.
1.1. The Exterior Gateway Protocol
Requirements for near-term interoperability between the BBN core gateways and the remainder of the gateway population implemented by other organizations required that an interim protocol be developed with the capability of exchanging reachability information, but not necessarily the capability to function as a true routing algorithm. This protocol is called the Exterior Gateway Protocol (EGP) and is documented in RFC-904 .