The current BGP-4 protocol specification [RFC4271] states that the
selection process chooses the best path for a given route which is
added to the Loc-Rib and advertised to all peers.
Previous versions [RFC1771] of the specification defined a different
rule for Internal BGP Updates. Given that Internal paths are not re-
advertised to Internal peers, it was specified that the best of the
external paths, as determined by the path selection tie breaking
algorithm, would be advertised to Internal peers.
This document extends that procedure to operate in environments where
Route Reflection [RFC4456] or Confederations [RFC5065] are used and
explains why advertising the additional routing information can
improve convergence time without causing routing loops.
Additional benefits include reduction of inter-domain churn and
avoidance of permanent route oscillation.