gtps2m12 | ACF/SNA Data Communications Reference |
SNA commands (VTAM VARY NET) are used to control the network. In SNA processing, this is accomplished via the nodename of the NCP, the SNA line, and the physical and logical units. As SNA does not have a node name for ALC terminals, they must be addressed via an LEID.
The user controls the assignment of the LEID to each ALC terminal.
Normal ALC command support is not provided for NEF/AX.25 devices except for terminals. This portion of the network is not controlled or displayed via the ZL--type command. It is not considered a true high speed line.
Command support for terminals falls into two categories:
The convert node name (ZNCVT), alter/display CRAS (ZACRS/ZDCRS), and 1052 fallback functions fall into the category of 3270 SDLC support. Here, LEID is used to locate the resource vector table (RVT) entry. See TPF Operations for more information on each of these commands.
An NEF/AX.25/XALCI terminal operator can operate from either a prime or alternate CRAS. Therefore, an entry is placed in the computer room agent table (CRAT). As a result of this, a terminal operator can log into application SMPx (where x is the symbolic CPU ID) and enter Z-type commands to the system message processor (CSMP).
The Terminal Reset function (ZLRST), applicable only to NEF support, requires special interfaces. Here, it is necessary to use the pseudo ALC address (LEID) to locate the SNA resource vector table, rather than the system communication keypoints. Normally this is done when the package detects what appears to be an invalid symbolic line number. The terminal reset function allows a system operator to reset a 1980-24 printer's buffer (see CVTR). NEF support does not provide for the terminal interchange (TI) reset function. This function can only be performed from the owning VTAM CMC by activating the physical unit (ACTPU) of that terminal interchange. ACTPU, in turn, causes NEF in the 37x5 to generate a configuration report. This configuration report gives TPF the information about the correlation between the NEF logical unit (represented by an entry in the RVT) and the NEF terminals (LEIDs, entries in WGTA).