The BGP Tables

BGP uses three tables for maintaining a network prefix and the path attributes (PA)
associated with each path for a prefix.

Table Name Description
Adj-RIB-in Contains the NLRI (network prefix and prefix-length) and BGP PAs in the original form that they are received from a BGP peer.
The Adj-RIB-in table is purged after all route policies are processed to save memory.

# show ip bgp neighbor x.x.x.x received-routes
Loc-RIB Contains all the NLRIs that originate locally or that came from the Adj-RIB-in table after passing any inbound route policy processing.
Note that BGP PAs in the Loc-RIB might have been modified by the router’s inbound route policies for a specific neighbor.

After NLRIs pass the validity and next-hop reachability check, the BGP best path algorithm selects the best path for a specific prefix.
The Loc-RIB table is the table used for presenting routes to the IP routing table.

# show bgp ipv4 unicast / show ip bgp
Adj-RIB-out Contains the NLRIs after outbound route policies have processed.
Different outbound route policies could exist between neighbors, so the Adj-RIB-out keeps track of the neighbors and the NLRIs for each neighbor.
Outbound route policies could modify PAs for a specific neighbor.

# show ip bgp neighbor x.x.x.x advertised-routes
bgp tables

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