In a local area network, a node is definied as each PC that executes A-Shell.  In UNIX/Linux systems, a node is defined as a user login, and each such logon counts as one node.

These definitions cover most situations and should give you enough information to comply with the intent of the A-Shell license agreement.  Some special circumstances are described below.

Background tasks (UNIX only):  All background tasks together, whether spawned via an XCALL or SUBMITted, count as one node.  This means that a station running background tasks needs two A-Shell nodes: one for the foreground job, and one for all (not each) of the background jobs.

Telnet (UNIX only): Each telnet session is a node, even if multiple sessions originate from same PC.

If using ATSD to telnet into Windows, we allow multiple sessions originating from the same IP to count as "logical" (not counting against the node license, as opposed to "physical", which do).  There is a limit to this largesse though: you cannot have more than the maximum node license from any one IP address (or 5, whichever is greater.)  This is to prevent people from buying a N-user license,  and then connecting N*M users via a telnet proxy to it.

Multi-tasking (UNIX only): Each user session generated by a multi-tasking utility, such as FacetTerm, counts as a node.  PolyShell is exempted from this requirement.