With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cgkLocalZoneStatsUnRegistrationTable
Cisco Gatekeeper Local Zone Stats Un Registration Table
1.3.6.1.4.1.9.10.40.1.1.4.4
This table contains the information about UnRegistration statistics data for a local zone managed by this Gatekeeper. If cgkZoneLocalZone is 'false' for a particular zone, there will be no entry in this table for that cgkZoneIndex.
Back to CISCO-GATEKEEPER-MIB MIB page.
IPHost Network monitor allows you to monitor cgkLocalZoneStatsUnRegistrationTable on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco switches right now.