The required troubleshooting steps of IBGP peering sessions.
  • Routers are not able to establish a full mesh of IBGP peering sessions using the loopback interface as the IBGP neighbor IP address.
    The required troubleshooting steps, with the lowest OSI layer as the topmost, The steps from the lowest to the highest layer, using a bottom-up approach.

    A. Check if each router can ping the loopback interface of all the other routers.
    Check the router interface status to see if it is in the up/up state.
    Check the BGP configurations on all the routers.
    Check if the routers are learning the loopback interface of the other routers via the IGP.
    B. Check the router interface status to see if it is in the up/up state.
    Check if each router can ping the loopback interface of all the other routers.
    Check if the routers are learning the loopback interface of the other routers via the IGP.
    Check the BGP configurations on all the routers.
    C. Check if each router can ping the loopback interface of all the other routers.
    Check if the routers are learning the loopback interface of the other routers via the IGP.
    Check the BGP configurations on all the routers.
    Check the router interface status to see if it is in the up/up state.
    D. Check if the routers are learning the loopback interface of the other routers via the IGP.
    Check the BGP configurations on all the routers.
    Check the router interface status to see if it is in the up/up state.
    Check if each router can ping the loopback interface of all the other routers. 8)