How BGP finds the Best Path

Ignore routes with an inaccessible next hop address!

  1. Prefer the path with the highest WEIGHT (Cisco proprietary and only of local significance).
  2. Prefer the path the with highest LOCAL_PREF.
  3. Prefer the path that was locally originated via a network command.
  4. Prefer the path with the shortest AS_PATH. **
  5. Prefer the path with the lowest origin type.
  6. Prefer the path with the lowest multi-exit discriminator (MED)
  7. Prefer eBGP over iBGP paths.
  8. Prefer the path with the lowest IGP metric to the BGP hop.
  9. Determine if multiple paths require installation in the routing table for BGP Multipath.
  10. When both paths are external, prefer the path that was received first (the oldest one).
  11. Prefer the route that omces from the BGP router with the lowest router ID.
  12. If the originator or router ID is the same for multiple paths, prefer the path with the minimum cluster list length.
  13. Prefer the path that comes from the lowest neighbor address.

** This attribute is the normal tie-breaker if all settings are left at default.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.