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

    Default: 100           Value: 0-65535

    Specifies the guaranteed number of buffers for forwarding. More
    buffers may be used if they are available.  You can only increase
    the characteristic value.