gtps2m13 | ACF/SNA Data Communications Reference |
NEF support must be present in any TPF host that communicates with a NEF terminal. A VTAM CMC host owns all NEF resources (lines, physical units, logical units). TPF hosts cannot own any NEF resources, but a given terminal can communicate with any one of the hosts provided that the terminal is defined (in WGTA) to that host.
Multiple host support requires two basic items:
To accommodate an SNA multiple host environment, a NEF LU is defined for each host. Figure 22 illustrates a multiple host network.
Each NEF terminal has a single address (LEID) that is known in each of the hosts. Therefore, user-assigned LEIDs for NEF terminals must define the first byte of the LEID outside the range of the symbolic line numbers in all of the hosts. Because the terminal has a direct link to each host, it is known to each host via its address, LEID, and the CPU ID of that host.