I-D ACTION:draft-white-pathconsiderations-07.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Considerations in Validating the Path in BGP
	Author(s)	: R. White, et al.
	Filename	: draft-white-pathconsiderations-07.txt
	Pages		: 16
	Date		: 2006-8-1

A good deal of thought has gone into, and is currently being given
to, validating the path to a destination advertised by BGP.  The
purpose of this work is to explain the issues in validating a BGP AS
Path, in the expectation that it will help in the evaluation of
schemes seeking to improve path validation.  The first section
defines at least some of the types of questions a BGP speaker
receiving an update from a peer not in the local autonomous system
(AS) could ask about the information within the routing update.  The
sections following examine the answers to these questions in
consideration of specific deployments of BGP.

The examples given in this draft are intended to distill deployments
down to their most critical components, making the examples easier to
understand and consider.  In many situations, the specific path taken
in the example may not be relevant, but that does not nullify the
principles considered in each example.  It has been suggested that
these examples are "red herrings," because they do not illustrate
actual problems with specific policies.  On the contrary, these
examples are powerful because they are simple.  Any topology in which
one of these example topologies is a subtopology will exhibit the
characteristics explained in this draft.  Rather than focusing on a
specific topology, then dismissing that single topology as a "corner
case," this draft shows the basic issues with assertions about the AS
Path attribute within BGP.  These generalized issues can then be
applied to more specific cases.

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