With IPHost Network Monitor you can run simple snmp requests against a IBM device in your network.
ibmdlswTConnGroupOperJoinTime
ibmdlsw T Connection Group Operation Join Time
1.3.6.1.4.1.2.6.119.4.3.1.1.3
The amount of time (in hundredths of a second) since this DLSw node last became a member of this group.
Back to ibm-ibmiroc MIB page.
IPHost Network monitor allows you to monitor ibmdlswTConnGroupOperJoinTime on IBM device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring IBM switches right now.