Refer to topology diagram. The Rl, R2, R3, and R4 routers are not able to establish a full mesh of
IBGP peering sessions using the loopback interface as the IBGP neighbor IP address.
Drag the required troubleshooting steps on the left and drop them in the boxes on the right, with
the lowest OSI layer as the topmost box .Place the steps from the lowest to the highest layer,
using a bottom-up a approach.
Building Cisco Service Provider Next- Generation Networks