BGP sessions

A BGP session refers to the established adjacency between two BGP routers. BGP sessions are always point-to-point and are categorized into two types:
  • Internal BGP (IBGP): Sessions established with an IBGP router that are in the same AS. IBGP prefixes are assigned an administrative distance (AD) of 200 upon installing into the router routing information base (RIB).

  • External BGP (EBGP): Sessions established with a BGP router that are in a different AS. EBGP prefixes are assigned an AD of 20 upon installing into the router RIB.