The entity hierarchy of the X25 Relay module is:

    Node___X25_Relay____Client
                      |
                      |_PVC

    An X25 RELAY CLIENT entity provides a set of default values to be
    used to set up a relay between an incoming call and an outgoing
    call.

    An X25 RELAY PVC entity provides a set of default values to
    be used to establish a connection to a client over a permanent
    virtual circuit.