Advertisement of the best external route in BGP

Document Type Expired Internet-Draft (idr WG)
Last updated 2012-07-06 (latest revision 2012-01-03)
Replaces draft-marques-idr-best-external
Stream IETF
Intended RFC status (None)
Expired & archived
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Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


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.


Pedro Marques (
Rex Fernando (
Enke Chen (
Pradosh Mohapatra (
Hannes Gredler (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)