With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
tn3270sStatsSpareSess
tn3270s Stats Spare Sess
1.3.6.1.4.1.9.9.54.1.2.1.1.4
Spare number of TN3270 sessions available for connect at query time.
Back to CISCO-TN3270SERVER-MIB MIB page.
IPHost Network monitor allows you to monitor tn3270sStatsSpareSess on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.