3.7.a Describe implement and troubleshoot peer relationships

from rfc 4271:

3.2.  Routing Information Base

The Routing Information Base (RIB) within a BGP speaker consists of
three distinct parts:

a) Adj-RIBs-In: The Adj-RIBs-In stores routing information learned
from inbound UPDATE messages that were received from other BGP
speakers.  Their contents represent routes that are available
as input to the Decision Process.

b) Loc-RIB: The Loc-RIB contains the local routing information the
BGP speaker selected by applying its local policies to the
routing information contained in its Adj-RIBs-In.  These are
the routes that will be used by the local BGP speaker.  The
next hop for each of these routes MUST be resolvable via the
local BGP speaker’s Routing Table.

c) Adj-RIBs-Out: The Adj-RIBs-Out stores information the local BGP
speaker selected for advertisement to its peers.  The routing
information stored in the Adj-RIBs-Out will be carried in the
local BGP speaker’s UPDATE messages and advertised to its
peers.

In summary, the Adj-RIBs-In contains unprocessed routing information
that has been advertised to the local BGP speaker by its peers; the
Loc-RIB contains the routes that have been selected by the local BGP
speaker’s Decision Process; and the Adj-RIBs-Out organizes the routes
for advertisement to specific peers (by means of the local speaker’s
UPDATE messages).