The Multi-Level Path Vector Routing Scheme

			Bala Rajagopalan
			AT&T Bell Labs
		  (email: braja@qsun.att.com)


			Paul Francis
			  Bellcore
		(email: francis@thumper.bellcore.com)


			March, 19, 1993



			ABSTRACT

This document describes protocols that are part of the Multi-Level Path Vector 
(MLPV) routing scheme being developed for use in PIP internets. MLPV is a 
hierarchical routing scheme.  It allows an arbitrary number of levels in the 
topological hierarchy and arbitrary interconnections within and across levels.
Conceptually, the execution of MLPV in a PIP router consists of
running multiple, independent instances of a path vector routing
algorithm, one for each level of the hierarchy that routes are being
computed. This document describes the MLPV topological model and
specifies the basic path vector routing schemes used at various
levels of the hierarchy.