The Border Gateway Protocol, version 4, (BGP4) provides the means to
advertise reachability for IP prefixes. This reachability
information is propagated in a peer-to-peer topology. Routes may be
announced to neighbors, contrary to the receiver's local peering
policy. If that occurs, those routes may then be propagated
indiscriminantly, once they have been accepted.
This document considers the situations that can lead to routes being
leaked, and tries to find acceptable definitions for describing these
The purpose of these definitions is to facilitate analysis of what a
route leak is, and what the scope of the problem space for route
This, in turn, is intended to inform a requirements document for
detection of (and prevention of) route leaks. And finally, the
definitions and requirements are intended to allow proposed solutions
which meet these criteria, and to facilitate evaluation of proposed
The ultimate goal is to "solve the route leaks problem".