This value hands out the next available SNA (Systems Network Architecture) session ID; each time a management station reads it, it returns a free ID that the client should immediately write back via an SNMP SET to actually reserve that session. Administrators and SNA client applications use this test-and-increment mechanism so multiple SNA clients running at once don't collide on the same session ID, with error responses covering cases like the ID being taken already or the session table being full. For example, an SNA gateway management app might read this object, get back session ID 47, then SET the value 47 back to claim and initialize that session's event database.