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

    Support: All
    Default: 63            Value: 2-255

    Value to be placed in the "lifetime" field of originating data
    packets. This value should be greater than the maximum number of
    hops in any path in the network, plus the maximum packet lifetime
    in half-seconds.