Library /sys$common/syshlp/ncphelp.hlb SET, EXECUTOR, MAXIMUM BUFFERS number  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Specifies the maximum number of buffers in the transmit buffer pool.
 DECnet normally allocates only what it needs.  At minimum, use a value
 that is 15 times the square root of the number of lines.  Increase
 this value if you experience congestion loss.  The default value
 is 100.