The entity hierarchy for the Routing module is:

                      _Destination_Area
                     |                        _Adjacency
                     |                       |_IP_Address_Translation
                     |_Circuit_______________|_IP_Adjacency
                     |                       |_IP_Reachable_Address
                     |                       |_Reachable_Address
    Node___Routing___|
                     |_EGP_Group_______________EGP_Neighbor
                     |_Destination_Node
                     |_IP_Destination_Address
                     |_Port
                     |_Permitted_Neighbor

    The ROUTING entity is the top-level entity in the Routing module
    hierarchy of entities. The Routing module controls the operation
    of network routing within a node.

    A ROUTING DESTINATION AREA entity contains information about a
    destination area or reachable address prefix. These entities are
    created and deleted dynamically by the Routing module.

    Destination areas exist only on nodes that are level 2 routers.
    The address-prefix is the destination area managed by this
    command.

    A ROUTING CIRCUIT entity represents a data link to another node.
    The circuit-name refers the circuit managed by this command.

    A ROUTING CIRCUIT ADJACENCY entity describes an adjacency,
    which is a neighboring node that is accessible via a particular
    circuit. The circuit-name refers to the circuit associated
    with the specified adjacency. The adjacency-name refers to the
    adjacency managed by this command.

    The create and delete commands are allowed only if circuit
    is csma-cd and type is L1router or L2router. In addition, the
    delete command is allowed on end systems only for x25 da circuit
    adjacencies.

    A ROUTING CIRCUIT IP ADDRESS TRANSLATION entity describes the
    mapping between the IP address of an IP adjacency on a broadcast
    circuit and its LAN address. This entity is supported only
    on systems that support dual routing. ip address translation
    entities are created automatically, but can be deleted manually.

    A ROUTING CIRCUIT IP REACHABLE ADDRESS entity describes a
    manually entered subnet address that is accessible by way of
    a specified circuit. An IP reachable address allows a level 2
    router at the boundary of a routing domain to include information
    about the address and reachability of subnetworks outside the
    domain. IP reachable addresses exist only on level 2 routers that
    support dual routing.

    A ROUTING CIRCUIT REACHABLE ADDRESS entity describes information
    about a manually entered address prefix accessible over that circuit.
    It exists only on L2 routers and end nodes. On L2 routers the
    type may be outbound or inbound.

    A reachable address of type outbound (default) describes address
    prefixes in an external domain that are reachable by outbound
    traffic over this circuit. For end systems, the circuit can be
    either an X.25 DA circuit or a broadcast circuit on L2 routers.
    The routing information contained in the reachable address is
    entered directly into the L2 decision process. When
    ManualL2Algorithm has the value routing vector, only reachable
    addresses with address prefixes corresponding to Phase IV areas are
    fed into the decision process.

    On an L2 router, an inbound reachable address describes address
    prefixes corresponding to Phase IV areas which are reachable
    through the local node by inbound traffic over this circuit. The
    routing information contained in the reachable address (area and cost)
    is entered into a Phase IV routing vector message, which is
    transmitted periodically over this circuit.

    On an end system the type may be outbound or (for a broadcast
    circuit only) filter. A reachable address of type outbound behaves
    in a similar way to that on an L2 router except that the routing
    information is used to control the operation of the ES cache. A
    reachable address of type filter (for a broadcast circuit only)
    specifies the permitted LAN addresses of routers on the LAN that
    will be used by the cache algorithm.

    For either outbound or filter type, the mapping attribute should be
    set to manual because the default is X.121.

    A ROUTING DESTINATION NODE entity contains information about a
    particular destination node within the same area as this node.
    These entities are created and deleted automatically by the
    Routing module. Destination nodes exist only on nodes that are
    level 1 or level 2 routers.

    A ROUTING EGP GROUP entity defines a set of systems in the
    same autonomous system with which this system may exchange
    EGP messages. This entity is supported only on level 2 routers
    that support dual routing (and, in particular, the EGP routing
    protocol).

    A ROUTING EGP GROUP EGP NEIGHBOR entity defines one of the
    systems in the autonomous group defined by the owning egp
    group entity. This entity is supported only on level 2 routers
    that support dual routing (and, in particular, the EGP routing
    protocol).

    A ROUTING IP DESTINATION ADDRESS entity describes IP routing
    information in the shortest paths database. This entity is
    supported only on routers that support dual routing.

    A ROUTING PERMITTED NEIGHBOR entity represents a neighboring node
    on a nonbroadcast circuit that is permitted to connect to this
    node. The neighbor-name is the name of the permitted neighbor
    managed by this command.

    A ROUTING PORT entity represents a client of the Routing module,
    and presents information associated with that client. The port-
    name refers to the port managed by this command.