BGP Routing Information Bases (RIBs)

Adj-RIBs-In

• Description: The Adjacency RIB-In (Adj-RIBs-In) is the routing database that contains all unprocessed BGP routing information received from BGP peers.
• Count: There is typically one Adj-RIBs-In per BGP neighbor or peer.
• Role in BGP Best Path Selection: The BGP Best Path Selection Algorithm uses the information in this table to determine "the best" route among the received routes.
• Viewing Routes: You can see the routes in the Adj-RIBs-In with commands such as:
  • show ip bgp neighbor x.x.x.x received-routes
  • show bgp ipv4 unicast neighbor x.x.x.x received-routes

BGP Loc-RIB

• Description: The BGP Local Routing Information Base (BGP Loc-RIB) is the main BGP routing table where "the best" route is determined and displayed. It also contains information about alternative routes.
• Route Selection: This is where the BGP Best Path Selection Algorithm determines and displays "the best" route.
• Viewing Routes: You can see the routes in the BGP Loc-RIB by running commands like:
  • show ip bgp
  • show bgp ipv4 unicast

Adj-RIBs-Out

• Description: The Adjacency RIB-Out (Adj-RIBs-Out) is the routing database that contains all the processed outgoing BGP routing information to be advertised to BGP peers.
• Count: There is typically one Adj-RIBs-Out per BGP neighbor.
• Viewing Routes: You can see the routes in the Adj-RIBs-Out by running commands such as:
  • show ip bgp neighbor x.x.x.x advertised-routes
  • show bgp ipv4 unicast neighbor x.x.x.x advertised-routes

BGP RIBs play a crucial role in the BGP routing process by storing and managing routing information for decision-making and routing updates. Understanding these RIBs is essential for managing BGP routes effectively.


Image source: INE and Travis Bonfigli