Library /sys$common/syshlp/nclhelp.hlb set, routing, circuit, originating_queue_limit  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Support: L1,L2
    Default: 2             Value: 1-50

    Maximum number of data PDUs originated by this node that can
    be on this circuit's transmit queue. This should be set to the
    minimum number required to keep the data link from idling. You
    can modify this characteristic to a higher value when the entity
    is disabled; you can never modify it to a lower value.